Dave Grant: The Straits of Florida, March 3, 2012

NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: March 3, 2012

Weather Data from the Bridge

Position:30 deg 37 min North Latitude & 79 deg 29 min West Longitude
Windspeed: 30 knots
Wind Direction: North
Air Temperature: 14.1 deg C / 57.4 deg F
Water Temperature: 25.6 deg C / 78.4 deg F
Atm Pressure: 1007.2 mb
Water Depth:740 meters / 2428 feet
Cloud Cover: 85%
Cloud Type: Cumulonimbus and Stratus

Science/Technology Log:

Entering the  Gulf Stream and Straits of Florida

“There is in the world no other such majestic flow of waters.
Its current is more rapid than the Mississippi or the Amazon.
Its waters, as far out from the Gulf as the Carolina coasts, are of an indigo blue.
They are so distinctly marked that their line of junction with the common sea-water
may be traced by the eye.”

Matthew Maury – The Physical Geography of the Sea

 While our cruise could hardly be called leisurely, most sampling has been spread out between sites, sometimes involving day-long periods on station while the CTD and moorings are recovered from great depths (5,000 meters). However, Chief Scientist Dr. Baringer regularly reminds us that west of the Bahamas in the Gulf Stream transect, our stations are in much shallower water (≤800 meters) and close together (The Florida Straits are only about 50 miles wide), so we should anticipate increased activity on deck and in the lab. In addition to the hydrology measurements, we will deploy a specialized net to sample those minute creatures that live at the surface film of the water – the neuston.

The Neuston net is deployed for a 10-minute tow.

The Neuston net is deployed for a 10-minute tow.

Now that we have crossed the Bahama Banks and are on-station, the routine is, as expected, very condensed, and there is little time to rest. What I did not anticipate was the great flow of the Gulf Stream and the challenge to the crew to keep the Brown on our East-West transect line as the current forces us north.  Additionally, as Wordsworth wrote, “with ships the sea was sprinkled far and wide”  and  we had to avoid many other craft, including another research ship sampling in the same area.

Ben Franklin is famous for having produced the first chart of this great Western Boundary Current, but naval officer Matthew Maury – America’s Scientist of the Sea – and author of what is recognized as the first oceanography text, best described it.  Remarkably, in The Physical Geography of the Sea, first published in 1855, he anticipates the significance of this major climate study project and summarizes it in a short and often-quoted paragraph:

“There is a river in the ocean. In the severest of droughts it never fails,
and in the mightiest floods it never overflows.
Its banks and its bottom are of cold water, while its current is of warm.
The Gulf of Mexico is its fountain, and its mouth is the Arctic seas.
It is the Gulf Stream.”

 

Gulf Stream water

CTD data from the Straits of Florida
1. Note that temperature (Red) decreases steadily with depth from about 26-degrees C at the surface,
to less than 10-degrees C at 700 meters. (Most of the ocean’s waters are cool where not warmed by sunlight).
2. Dissolved Oxygen (Green) varies considerably from a maximum at the surface, with a sharp decline at about 100 meters, and a more gradual decline to about 700 meters. (Phytoplankton in surface water produce excess oxygen through photosynthesis during daylight hours. At night and below about 100 meters, respiration predominates and organisms reduce the level of dissolved oxygen.)
3. Salinity (Blue) is related to atmospheric processes (Precipitation and Evaporation) and also varies according to depth, being saltiest at about 150 meters.

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“Ron Brown: Phone Home!”

At Midnight, just within sight of the beam of the Jupiter Inlet Lighthouse (And to the relief of the home-sick sailors on board – “Finally –  after  more than two weeks, we are within the range of cell phone towers!”) we began our studies of the Straits of Florida and the Gulf Stream. Nine stations in rapid order – standing-by for a CTD cast, and then turning into the current to set the neuston net for a ten-minute tow.

The purpose of the net is to sample creatures that live on or visit the interface between air and water, so the mouth of the net is only half submerged. Neuston comes from the Greek for swimming and in warm waters a variety of invertebrates and even some young mesopelagic fishes rise within a few centimeters of the surface at night to filter phytoplankton and bacteria, and feed upon other zooplankton and even drowned terrestrial insects that have been blown out to sea.

On the upper side of this water/atmosphere interface, a smaller variety of floating invertebrates, notably Physalia  and Velella (Portuguese man-of-war and By-the-wind-sailor) use gas-filled buoyancy chambers or surface tension to ride the winds and currents. This much smaller group of seafarers is further classified by oceanographers as Pleuston.

Prior to this cruise, my experience with such a sampling device was limited – Years ago, spending miserable nights sailing in choppy seas off of Sandy Hook, NJ searching  for fishes eggs and larva rising to the surface after dark; and later, much more enjoyable times studying water striders – peculiar insects that spend their lives utilizing surface tension to skate along the surface of Cape Cod ponds.

Our CTD and net casts are complicated by rising winds and chop, but some great samples were retrieved. Once the net is recovered, we rinse it down with the seawater hose, collect everything from the bottle at the cod end, rinse off and separate the great mass of weed (Sargassum) and pickle the neuston in bottles of alcohol for analysis back at the lab.

Midnight shift: Recovering the net by moonlight.

Midnight shift: Recovering the net by moonlight.

Midnight shift: Recovering the net by moonlight.

Midnight shift: Recovering the net by moonlight.

Since much of the zooplankton community rises closer to the surface at night where phytoplankton is more concentrated and the chances of being preyed upon are slimmer, there are some noticeable differences in the samples taken then and during daylight hours. Unavoidably, both samples contain great quantities of Sargassum but the weed-colored carapaces of the different crustaceans are a clue to which specimens are from the Sargassum community and which are not.

Gulfweed Shrimp - Latreutes

Gulfweed Shrimp – Latreutes

We hit the jackpot early; snaring a variety of invertebrates and fishes, including the extraordinarily well-camouflaged Sargassum fish – a piscatorial phenomenon I’ve hoped to see ever since I was a kid reading William Beebe’s classic The Arcturus Adventure. What a tenuous existence for such a vulnerable and weak swimmer, hugging the Sargassum as it is dashed about in the waves. Even with its weed-like disguise and ability to blend in with the plants, it must lead a challenging life.

A unique member of the otherwise bottom-dwelling frogfishes, the Histrio histrio has smooth skin, and spends its life hitch-hiking along in the gulf-weed forest. Like other members of the family Antennariidae, it is an ambush predator, luring other creatures to their doom by angling with its fleshy fins.

The Sargassum fish (Histrio)

The Sargassum fish (Histrio)

Needlefish and Sargassum fish

Needlefish and Sargassum fish

Another highlight for me is the water striders we found in several samples. These “true bugs” (Hemiptera) are remarkable for several reasons. Most varieties of these “pond-skaters” (Or Jesus Bugs if you are from Texas) are found on calm freshwater lakes and streams, but a few members of this family (Gerridae) are the only true marine insects – representing a tentative Arthropod reinvasion of the sea after their splendid foray onto land hundreds of millions of years ago.

Two great finds: Sygnathus pelagicus– A Sargassum pipefish – a cousin of the sea horse. Halobates – the water strider. An example of the Pleuston community.

Two great finds:
Sygnathus pelagicus– A Sargassum pipefish – a cousin of the sea horse.
Halobates – the water strider. An example of the Pleuston community.

Using surface tension to their advantage, they “skate” along by flicking their middle and hind legs, and can even “communicate” with each other by vibrating the surface of the water with the hair-like setae on their feet. On lakes their prey is other insects like mosquito larvae, confined to the surface. How they manage to find food and communicate at the surface of the raging sea is a mystery, but whatever the means, they are adept at it, and we recovered them in half of the samples.

The ocean's insect: The  remarkable water stride

The ocean’s insect: The remarkable water stride

The scientists who provided the net are generally more interested in ichthyoplankton to monitor fish eggs and larvae to predict population trends, and monitor impacts like oil spills; so this is why samples are preserved to return to the lab in Miami.

Before packing up things after our marathon sampling spree I was able to examine our catch and observed a few things:
1. I am the “High-Hook” on the cruise – catching far more fishes (albeit tiny ones) than the rest of the crew with their fishing poles. (Needlefish, sargassum fish, pipe fish, filefish and several larval species)
2. Depending on the time of day the samples were taken, there is a marked difference in the quantity and composition of organisms that have separated from the Sargassum and settled in the sample jars – (Noticeably more at night than during daylight hours).
3. There appears to be a greater variety of sea grasses present (Turtle grass, etc.) on the eastern (Bahamas side) of the Straits. We observed one seabean – drift seeds and fruits (or disseminules) from terrestrial plants.
4. Plastic bits are present in all samples – particularly plastic ties (Table 1.)

Settled organisms in sample jars.

Settled organisms in sample jars.

Sargassum fauna: Portunid crab – with eggs on her belly.
(Portunus was a Roman god – Protector of harbors and gates,
who supposedly also invented navigation)

Belly view of a Caridean shrimp

Belly view of a Caridean shrimp

A tiny fish egg ready to hatch!

A tiny fish egg ready to hatch!

A larval fish begins its perilous journey in the Gulf Stream.

A larval fish begins its perilous journey in the Gulf Stream.

Site/Local time

Notable Contents*

Biomass Site Depth
8 Day 17:48 Weed, Grasses(3 spp) 3.0 mm 79˚12’ 485 m
7 Day 16:10 Grasses(4 spp) 2.0 mm 79˚17’ 616 m
6 Day 14:30 Grasses(2 spp) Fish eggs and larva Trace 79˚22’ 708 m
5 Day 12:45 Water striders, Grass (1 spp) Trace 79˚30’ 759 m
4 Day 10:13 Crustacean larva, shrimp (large), 7.0 mm 79˚36’ 646 m
3 Dawn 07:53 Crustacean larva, shrimp (large), water striders Trace 79˚41’ 543 m
2 Night 05:10 Crustacean larva, shrimp (small), Pipefish, water striders 7.0 mm 79˚46’ 388 m
1 Night 02:48 Crustacean larva, shrimp, needlefish, Sargassum fish, Herring(?), Portunid crabs, shrimp (large), Copepods 13 mm 79˚51’ 264 m
0 Night 00:37 Crustacean larva, shrimp, Copepods 25 mm 79˚56’ 148 m

*Plastic bits and Sargassum weed and its endemic epibionts are present in all samples.

Table 1.   Contents in sample jars.

There is a marked difference in the quantity and composition of organisms collected at night (Left).

There is a marked difference in the quantity and composition of organisms collected at night (Left).

There is a marked difference in the quantity and composition of organisms collected at night (Left) and during the day (Right).

There is a marked difference in the quantity and composition of organisms collected during the day (Right).

With sampling completed we steer north to ride the Gulf Stream towards the Brown’s home-port,  and turn away from the bright lights of Florida …

“Where the spent lights quiver and gleam;
Where the salt weed sways in the stream;
Where the sea-beasts rang’d all around
Feed in the ooze of their pasture ground:”

Matthew Arnold

"Red sky at morning...sailor take warning!"

“Red sky at morning…sailor take warning!”

Homeward bound:

A storm battering the Midwest will impede our progress back north to Charleston and threatens to bring us the only foul weather of the cruise. Note the location of the cold front over the Florida Straits.

“Now the great winds shoreward blow;
Now the salt tides seaward flow;
Now the wild white horses play,
Champ and chafe and toss the spray.”
Matthew Arnold

As the sailors say: "The sheep are grazing." A gale is brewing and kicking up whitecaps as we sail north to Charleston.

As the sailors say: “The sheep are grazing.”
A gale is brewing and kicking up whitecaps as we sail north to Charleston.

Dave Grant: The “River in the Ocean”, March 2, 2012

NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: March 2, 2012

Weather Data from the Bridge

Position: 26 degrees 19 minutes North Latitude & 79 degrees 55 minutes West Longitude
Windspeed: 14 knots
Wind Direction: South
Air Temperature: 25.4 deg C / 77.7 deg F
Water Temperature: 26.1 deg C / 79 deg F
Atm Pressure: 1014.7 mb
Water Depth: 242 m / 794 feet
Cloud Cover: none
Cloud Type: NA

“The moment one gives close attention to anything, even a blade of grass,
it becomes a mysterious, awesome, indescribably magnificent world in itself.”

Henry Miller

My evenings looking through the microscope are a short course in invertebrate zoology. Every drop of water filtered through the plankton net reveals new and mystifying creatures. Perhaps 90% of marine invertebrates, like newly hatched mollusks and crustaceans, spend part of their life in a drifting stage – meroplankton; as opposed to holoplankton – organisms that are planktonic throughout their life cycle.

MOLLUSK LARVAE

Bivalve

Bivalve

 Univalve

Univalve

The lucky individuals that escape being eaten, and are near a suitable substrate at the right moment, settle out into a sedentary life far from their place of origin. For the long distance travelers swept up in the Gulf Stream, the most fortunate waifs of the sea that survive long enough might make it all the way to Bermuda. The only hope for the remainder is to attach to a piece of flotsam or jetsam, or an unnatural and unlikely refuge like the electronic picket fence of moorings the Ron Brown is servicing east of the Bahamas.

“The gaudy, babbling, and remorseful day,
Is crept into the bosom of the sea.”
Shakespeare

A league and a half* of cable, sensors and a ton of anchor chain are wrestled on deck during a day-long operation in the tropical heat. (*A mariner’s league equals three nautical miles or 3041 fathoms [18,246 feet])

It is easy to be humbled by the immensity of the sea and the scope of the mooring project while observing miles of cable and buoys stretched towards the horizon, about to be set in place with a ton of anchor chain gingerly swung off the stern for its half-hour trip to the bosom of the sea.

Thanks to the hard labor and alert eyes of our British and French (“And Irish”) colleagues retrieving and deploying the attached temperature and salinity sensors, I am regularly directed to investigate “something crawling out of the gear” or to photograph bite marks from deep sea denizens on very expensive, but sturdy equipment.

A retrieved sensor with bite marks.

A retrieved sensor with bite marks.

To my surprise, other than teeth marks, very little evidence of marine life is present on the miles of lines and devices strung deeper than about 200 meters. This may be due in part to the materials of which they are constructed and protective coatings to prevent bio-fouling, but sunlight or more precisely, the attenuation of it as one goes deeper, is probably the most important factor.

Fireworm (Drawings and images by Dave Grant - NOAA Ron Brown)

Fireworm
(Drawings and images by Dave Grant – NOAA Ron Brown)

Handle with care! Close-up of worm spines

Handle with care! Close-up of worm spines

The first discovery I was directed to was a striking red bristle worm wiggling out of the crevice in a buoy.  It appears to be one of the reef-dwelling Amphinomids – the aptly-named fireworms that SCUBA divers in the Caribbean avoid because of their venomous spines; so I was cautious when handling it.  This proved to be the deepest-dwelling organism we found, along with some minute growths of stony and soft corals.

Five o’clock shadow” on a buoy – A year’s growth of fouling organisms – only an inch tall.

On shallower buoys and equipment, there are sparse growths of brown and blue-green algae, small numbers of goose barnacles, tiny coiled limey tubes of Serpulid worms like the Spirobis found on the floating gulfweed, some non-descript bivalves (Anomia?) covered with other fouling growth, skeleton shrimp creeping like inch-worms, and of course the ubiquitous Bryozoans. Searching through this depauperate community not as challenging as the plankton samples, but not surprising since our distance from land, reefs or upwelling areas – and especially clear water and lack of seabirds and fishes; are all indicators that this is a nutrient-deficient, less productive part of the ocean.

   

Bio-fouling – “on the half-shell.”                       Skeleton shrimp (Caprellidae)

The Ron Brown is the largest workhorse in the NOAA fleet and its labs and decks are intentionally cleared of equipment between cruises so that visiting scientists can bring aboard their own gear that is best suited to their specific project needs. NOAA’s physical oceanographers from Miami arrived with a truckload of crates holding Niskin water sampling bottles for the CTD and their chemistry equipment for DO (Dissolved Oxygen) and salinity measurements; and in a large shipping container (“Ship-tainer”) from England, the British and French (“and Irish”) scientists transported their own remote sensing gear, buoys, and (quite literally) tons of massive chain and cables to anchor their moorings. (I am surprised to learn from the “Brits” that the heavy chain is shipped all the way from England because it is increasingly hard to acquire. )

In the lab: Scores of sensors serviced and ready for deployment

In the lab: Scores of sensors serviced and ready for deployment

This is how most science is facilitated on the Brown and it requires many months of planning and pre-positioning of materials. I am lucky and can travel light – and with little advanced preparation. I am using simple methods to obtain plankton samples and images via a small portable microscope, digital camera and plankton net which I can cram into my backpack for any trips that involve large bodies of water. The little Swift* scope has three lens (4x, 10x, 40x) with a 10x ocular, and I get great resolution at 40x, and can get decent resolution to 100x. Using tips from Dave Bulloch (Handbook for the Marine Naturalist) I am able to push that somewhat with a simple Nikon Coolpix* point-and-shoot camera – but lose some of the sharpness with digital zoom.  As you might suspect, the ship’s movement and engine vibration can be a challenge when peering through the scope, but is satisfactory for some preliminary identification. (*These are not commercial endorsements, but I can be bought if either company is willing to fund my next cruise!)

PHYTOPLANKTON

Centric diatom - Coscinodiscus

Centric diatom – Coscinodiscus

    

Dinoflagellates –  Different Ceratium species

ZOOPLANKTON

A Plankton précis

Collecting specimens would be much more difficult without the cooperation of the Brown’s crew and visiting scientists, and their assistance is always reliable and appreciated. The least effective method of collection has been by filtering the deep, cold bottom water brought up in the Niskin bottles. As mentioned earlier, no live specimens were recovered; only fragments of diatom and Silicoflagellate skeletons surviving the slow drift to the bottom, which I have been able to identify through deep sea core images posted at the Consortium for Ocean Leadership website.

Needless to say, the most indiscriminate method of collection and the most material collected is through the large neuston net. The greatest biomass observed on the trip is the millions of tons of Sargassum weed, which covers the surface in great slacks around us that are even visible in satellite images.

Although the continuous flow of ocean water pumped into the wet lab and through my plankton net is effective and the most convenient collection method, the most surprising finds are from the saltwater intake screens that the engineer directed me to. This includes bizarre crystal-clear, inch-long, and paper-thin Phylosoma – larvae of tropical lobsters – that I initially mistook for pieces of plastic.

Inch-long Phylosoma larvae on a glass slide. (One of the tropical lobsters.)

Inch-long Phylosoma larvae on a glass slide. (One of the tropical lobsters.)

“All the ingenious men, and all the scientific men, and all the fanciful men in the world …
…could never invent anything so curious and so ridiculous, as a lobster.”

Charles Kingsley -The Water-Babies

Plankton communities are noticeably different between the Gulf Stream, inshore, and offshore in the pelagic waters east of the Bahamas.  Near the coast, either the shallower Bahama Banks or the neritic waters over the continental shelf closer to Charleston, the plankton is larger, more familiar to me and less challenging to sort, including: copepods, mollusk larvae and diatoms. Steaming over the shelf waters at night, the ship’s wake is often phosphorescent, and dinoflagellates, including the “night-light” Noctiluca are common in those samples.

Dinoflagellate - Noctiluca

Dinoflagellate – Noctiluca

 The waters east of the Bahamas along the transect line are notable for their zooplankton, including great numbers and varieties of Foraminifera, and some striking amphipod shrimp. Compared to cooler waters I am familiar with, subtropical waters here have over a dozen species of Forams, and some astonishingly colorful shrimp that come up nightly from deeper water.

It’s not all work and no play on the Ron Brown, and there are entertaining moments like decorating foam cups with school logos to send down with the CTD to document the extreme pressure at the bottom. Brought back to class, these graphically illustrate to younger students the challenges of deep sea research.

Foam cup:  Before-and-after a trip to 5,000 meters

Foam cup: Before-and-after a trip to 5,000 meters

Navigating by Dead-reckoning

On calm days while we are being held on-station by the Brown’s powerful thrusters, I can measure current speeds using Sargassum clumps as Dutchman’s logs as they drift by. Long before modern navigation devices, sailors would have to use dead-reckoning techniques to estimate their progress.  One method used a float attached to a measured spool of knotted line (A log-line), trailing behind the moving vessel. The navigator counted the number of knots that passed through his hands as the line played out behind the ship to estimate the vessel’s speed (in knots). Since nothing is to be tossed off the Brown, I rely on a simpler method by following the progress of the Sargassum as it drifts by stem-to-stern while we are stationary at our sampling site. Since I know the length of the Brown at the waterline (~100-meters), I can estimate current speed by observing drifting Sargassum.

Watching sargassum, I wonder if a swimmer could keep pace with the currents in these waters. When in college
my brothers and would strive to cover a 100-meter race by swimming it in under a minute. Here is the data from east of the Bahamas. See if you can determine the current speed there and if a good swimmer could keep pace.

ESTIMATING CURRENT SPEED

Data on currents:
Average of three measurements of Sargassum drifting  the length of the Ron Brown = 245 seconds.
Length of the Ron Brown – 100-meters.

1. How many meters per second is the current east of the Bahamas?
2. As a swimmer in college – with my best time in the 100-meters freestyle of one minute – could I have kept up with the Ron Brown… or been swept away towards the Bahamas?

For more on currents, visit my site at the college:
http://ux.brookdalecc.edu/staff/sandyhook/Student%20Page%201/TUTS-2-09-1/Index.html

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Other navigational exercises I try to include determining Latitude and Longitude. Latitude is easy as long as you can shoot the sun at midday or find the altitude of Polaris in the night sky; and sailors have done that for centuries. The ship’s navigator will get out the sextant for this, or, since the width of one’s fist is about 10-degrees of sky, I can estimate the height of both of these navigational beacons by counting the number of fists between the star and the horizon.

ESTIMATING LATITUDE

Data:
Night observation (Shooting the North Star) – Number of Fists from the Northern horizon to Polaris = 3
Day observation (Shooting the Sun) – Number of Fists from the Southern horizon to the Sun = 5.5

If the width of a fist is equal to about 10-degrees of horizon, our estimate of Latitude using Polaris is 30-degrees (3 x 10).
Not too bad an estimate on a rocking ship at night, compared to our actual location (See Data from the Bridge at the top.).

Shooting the Sun at its Zenith at 12:30 that day gives us its altitude as 55-degrees – which seems too high unless we consider the earth’s tilt (23.5-degrees). So if we deduct that (55 – 23.5) we get 31.5, which is closer to our actual position. And if we consult an Almanac, we know that the sun is still about six degrees below the Equator on its seasonal trip North; so by deducting that (31.5 – 6) we end up with an estimate of 25.5-degrees. This is an even better estimate of our Latitude.

Here is the dreaded word problem:

By shooting the Sun, our best estimate of Latitude is 25.5 degrees (25 degrees/30 minutes)
The actual Latitude of the ship using GPS is 26-degrees/19 minutes.
If there are 60 minutes to a degree of Latitude – each of those minutes representing a Nautical Mile – how many Nautical Miles off course does our estimate place us on the featureless sea?

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Longitude is much harder to determine if you don’t have an accurate timepiece to compare local time with universal time (The time at Greenwich, England), and an accurate ship’s chronometer wasn’t in use until the mid-1700’s.
To understand the challenge of designing a precise timepiece that reliably will function at sea, I used two crucial clock mechanisms:  a pendulum and a spring. Finding a spring was easy, since “Doc” had a scale at Sick Bay. For the pendulum I fashioned a small weight swinging on a string)

Using the scale to observe the ship’s motion.

Using the scale to observe the ship’s motion.

Standing on the scale and swinging the pendulum even in calm weather quickly demonstrated three things:

First: I have developed my sea legs, and no longer notice the regular motion of the ship.
Second: Even when the sea feels calm, the scale’s spring mechanism swings back and forth under my weight; adding and deducting 20 pounds to my real weight and reflecting the ship’s rocking that I no longer notice.
Three: On rough days, even if I can hold still, the ship’s heaving, pitching and rolling alters my pendulum’s reliable swing – its movements reflecting the ship’s indicator in the lab. Experimenting helps me appreciate clock-maker John Harrison, and his massive, 65-pound No. 1 Ship’s Chronometer  he presented to the Royal Navy in 1728.

Ship movement as recorded by the computer

Ship movement as recorded by the computer

Doc: Always on duty -  Sick Bay on the Ron Brown

Doc: Always on duty – Sick Bay on the Ron Brown

Besides having very well-provisioned Sick Bays, NOAA ships have experienced and very competent medical officers.  Our “Doc” received his training at Yale, and served as a medic during the Gulf War.

Especially alert to anyone who exhibits even the mildest symptoms of sea-sickness, Christian is available 24-hours for emergencies – and in spite of the crew constantly wrestling with heavy equipment on a rocking deck, we’ve only experienced a few minor bumps and bruises. He has regular office hours every day, and is constantly on the move around the ship when not on duty there.

Besides keeping us healthy, he helps keep the ship humming by testing the drinking water supply (The Brown desalinates seawater when underway, but takes on local water while in port); surveys all departments for safety issues; and with the Captain, has the final word if-or-when a cruise is to be terminated if there is a medical emergency.

Since a storm pounding the Midwest will head out to sea and cross our path when we head north to Charleston, he is reminding everyone that remedies for sea sickness are always available at his office door, and thanks to NASA and the space program, if the motion sickness pills don’t work, he has available stronger medicine. So far we have been blessed with relatively calm weather and a resilient crew.

                          The warm  (Red) Gulf Stream waters viewed from a satellite iamge.

The warm (Red) Gulf Stream waters viewed from a satellite image.

 Contact: The edge of the Gulf Stream - Matthew Maury’s  River in the Ocean

Contact: The edge of the Gulf Stream – Matthew Maury’s River in the Ocean

Birdwatching on the Ron Brown

For the time being I take advantage of the calm seas to scrutinize what’s under the microscope, and when on break, look for seabirds. East of the Bahamas, as anticipated after consulting ornithologist Poul Jespersen’s map of Atlantic bird sightings, I only spotted two birds over a two-week stretch at sea (storm petrels). This is very much in contrast to the dozens of species and hundreds of seabirds spotted in the rich waters of the Humboldt Current off of Chile , where I joined the Brown in 2008.
(http://ux.brookdalecc.edu/staff/Web%2012-2-04/seabirds/Brown%20terns%202/Terns%20%20fixed/SEPacific.html)

Passing through Bahamian waters was no more rewarding, but now that we are west and in the Florida Straits there are several species of gulls during the day, and at night more storm petrels startled by the ship’s lights. One windy night a large disoriented bird (Shearwater?) suddenly fluttered out of the dark and brushed my head before bumping a deck light and careening back out into the darkness. Throughout the day a cohort of terns has taken up watch on the forward mast of the Brown and noisily, they juggle for the best positions at the bow – resting until the ship flushes a school of flying fishes, and then swooping down across the water trying and snatch one in mid-air.  Like most fishermen, they are successful only about 10% of the time.

Royal tern "on station" at the jack mast.

Caspian tern “on station” at the jack mast.

Royal tern "on station" at the jack mast.

Royal tern “on station” at the jack mast.

  

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Despite the dreary forecast from the Captain, Wes and I are enthusiastic about all we have done on the cruise and formulated a list of why NOAA’s Teacher At Sea program is so rewarding.

Top Ten Reasons:
Why be a Teacher At Sea?

10. Fun and excitement exploring the oceans!

9. Meeting dedicated and diligent scientists and crew from around the world!

8. Bragging rights in the Teachers’ Room – and endless anecdotes!

7. Cool NOAA t-shirts, pins and hats from the Ship’s Store!

6. Great meals, three times a day…and FREE laundry!

5. Amazing sunsets, sunrises and star-watches!

4. Reporting on BIG science to students…and in real-time!

3. Outstanding and relevant knowledge brought back to students and colleagues!

2. First-hand experience that relates to your students’ career objectives!

1. Rewarding hours in the lab and fieldremembering why you love science and sharing it with students!

Powerpoint:
Shots from the deck and under the microscope

(Drawings and images by Dave Grant – NOAA Ron Brown)

Dave Grant: Fast, Flat and Flying Fishes, March 1, 2012

NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Gulf Stream waters
Date: March 1, 2012

Weather Data from the Bridge
Position: 26.30N Latitude – 79. 23W Longitude
Wind speed:  Calm
Wind direction: Calm
Air Temperature:  76E F
Atm Pressure: 1013. mb
Water Depth: 750 meters
Cloud Cover: 20%
Cloud Type: Cumulus

Personal Log

Our most persistent travel companions on the cruise are the flying fish and today they are the most abundant in the entire trip. Sit at the bow while we are plunging into the swells and it is impossible not to be mesmerized by what issues from the sea surface when old Triton blows his wreathed horn.

Over the eons, fishes have experimented with many different avenues of escape from predators and competition, and soaring out of the water is arguably the most dramatic and effective. There are scores of species in the family Exocoetidae, which comes from Greek roots and refers to “sleeping outside” – which was logical to ancient mariners who believed the flying fishes left the ocean to sleep on the shoreline. I check the Ron Brown’s deck each morning, hoping one has inadvertently landed on it, but without luck so far.

We flush them from both sides of the ship while underway.  Like birds of a feather flocking together, some escaping groups are about a foot long with a wing span (Oversized pectoral fins to be exact) about the same spread. Juveniles in other schools look no larger than the silver dollar George Washington threw across the Delaware River(Or did he skip it for greater distance like these little fishes do off the crests of waves?).

Between the sky, sea and sunsets, I thought I had seen all the shades of blue on this cruise, up to the moment we had a perfect view of a flying fish that soared past the railing and then steered off towards the horizon. Flying fish exhibit all the colors of the near end of the spectrum as their attitude and altitude change in flight. Taking advantage of the mesoscale winds generated between swells, the fishes launch off wave crests and can soar farther than a football field; sustaining the flight time by sweeping their tail laterally in the water.

Flying fish are harvested throughout the warmer waters of the ocean by man and beast, and are an important staple to island cultures. Barbados – to our south – is called the  “land of the flying fish” and on the reverse side of a dollar coin that I kept after a Caribbean trip, one finds the fish in flight.  When we are closer to land, I hope to see one of their main aerial opponents flying out to meet us – frigate birds.

Impossible to photograph, for the time being, I’ll be content to admire their flights during the day, and at night, watch them dodge the attacks of mahi-mahi under the ship’s lights.

Flying fish off the bow!

Mahi-Mahi

Our British colleagues remembered to bring fishing poles and the mahi-mahi is the most sought after and elusive creature out here when the ship is “on-station” doing sampling. Fishes and squid routinely come to the surface and congregate under the stern lights, and occasionally a large mahi will lurk in the shadows and dart in close to us chasing prey.

Also called dolphin-fish, our fishermen have learned only that the Hawaiian name Mahi-Mahi (Many Polynesian words are repeated) means “strong” since the hooked fishes have broken their fishing lines and escaped.

Mahi is popular in restaurants and is a light, mild tasting fish. Swimming under the lights they look pale and eel-like, but when landed in a boat they exhibit a range of shades from blue and green that fades to golden – hence the Spanish name Dorado.

A Mahi rises to the surface alongside the Ron Brown

Fish ON!

Finally the fishermen had some luck and landed a jack – but without a fish guide, that’s as far as I can go in identifying it (Although the term “tuna” is loosely applied to most things that swim by.)  Fortunately, I was able to get off an email and photo to Jeff Dement of the American Littoral Society (www.littoralsociety.org).

When not fishing, Jeff runs the largest independent fish tagging program in the country; distributing tags to recreational fishermen and analyzing their thousands of returns to document where fishes migrate to and how fast they grow.
His quick analysis directs us towards the lesser amberjack (Seriola fasciata) “based upon the shape of the snout, and the eye stripe length.”

Fast swimming and hard fighting, the amberjacks are popular gamefish on the line and in the skillet. Like most fish, they are tasty fried, broiled, baked, or grilled (I like fried…my doctor demands boiled, baked or grilled)

Like barracudas and some other apex predators of the reef, amberjacks are implicated in Ciguatera poisoning in humans. They acquire contaminants from eating herbivorous reef fishes that have ingested and accumulated Ciguatoxins produced by Dinoflagellates attached to marine algae they have been grazing upon. Harmless to the fishes, the poison is a neurotoxin in humans who are exposed to a concentrated dose from a top predator like the amberjack through the process called bioaccumulation. This is the same process that concentrates Mercury spewing into the atmosphere from coal-fired power plants, into the sea, then into plankton and forage fishes, and finally tuna.

An amberjack gets a close look at people before returning to the sea.

“You strange astonished-looking, angle-faced,
Dreary-mouthed, gaping wretches of the sea,
Gulping salt-water everlastingly,
Cold-blooded, though with red your blood be graced,
And mute, though dwellers in the roaring waste…
What is’t you do? what life lead? eh, dull goggles?
How do ye vary your dull days and nights?
How pass your Sundays? Are ye still but joggles,
In ceaseless wash? Still sought, but gapes and bites,
And drinks and stares, diversified with boggles.”

 (Leigh Hunt – The Man to the Fish)

It pays to be clear.

 For me, the catch of the day is a leptocephali – a larval fish as long as my index finger, that I almost overlooked in the samples.

A number of species go through this inconspicuous stage as zooplankton, and the most famous and intensely studied are the eels. American eels spend a year drifting to East Coast estuaries from their birthplace in the Sargasso Sea. The European species takes a more leisurely two-year tour of the North Atlantic on the Gulf Stream.

 (Images from the Ron Brown, by Dave Grant)

Dave Grant: Sea State, Sick Bay and Longitude, February 26, 2012

February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 26, 2012

Weather Data from the Bridge

Position: 26.30N Latitude – 71. 55W Longitude
Windspeed:  15 knots
Wind Direction: South (bearing 189 deg)
Air Temperature: 23.2 C / 74 F
Atm Pressure: 1013.9 mb
Water Depth: 17433 feet
Cloud Cover: 30%
Cloud Type: Cumulus

Sea State, Sick Bay and Longitude

“Now would I give a thousand furlongs of sea
for an acre of barren ground.”
Shakespeare – The Tempest.

There is considerable excitement on board since the winds have come up; adding to the work load of the deck crew and scientists struggling to snag the mooring buoy and haul in the miles of cable and sensors that are arrayed below. With swells arriving from two directions and wind chop on top of that, the ship’s motion is unpredictable. So there is no room for error above or below the waterline and the heaving of the ship and spray mean everyone must be alert and ready to respond instantly if anything swings loose.

We are “line-sailing” on this cruise, steaming back-and-forth while maintaining a straight course on Latitude 26.30; deploying and servicing various sampling devices on the electronic “picket fence” dividing the Atlantic. Watching the deck crew cutting heavy wire and even heavier  chain, banging on metal,  wrestling with equipment and sweating under the sun all day as they back-track along the same line doing back-breaking work, I can almost hear them singing an old Mississippi Delta field holler – Line ‘em:

“All I hate ’bout linin’ track
These ol’ bars ’bout to break my back
Moses stood on the Red Sea shore
Smotin’ that water with a two-by-four
If I could I surely would
Stand on the rock where Moses stood”

Line-sailing is also an old technique used when mariners could only accurately determine their latitude North or South of the equator by means of the sun and stars. Simply stated, one would sail North or South to the known latitude of a destination, then sail East or West until it was found.

The Polynesians perfected this – line-sailing the latitude of specific stars that they knew had islands beneath them. On clear nights we go out on the shadowy deck, so far away from the glare of lights on land, and marvel at the great spectacle of stars. The two brightest above us are Arcturus and Sirius – known to the Polynesians as Hōkūleʻa (Star of Joy) and Ka’ulua (Queen of Heaven). Navigators steered under Arcturus to reach Hawaii, and returned to Tahiti by sailing under Sirius.

Tahiti lies under Sirius, and Hawaii under Arcturus, providing navigators with bright sign posts to guide them to those jewels in the vast Pacific. From the deck on the Ron Brown it looks like our zenith star could be Pollux, one of twins in Gemini. This seems appropriate  “By Jiminy”  for good luck,  since early sailors swore an oath to those Twins – the protectors of ships.

Still, Longitude remained a problem because its measure is the time East or West from a fixed point –Greenwich, England and the Prime Meridian. Until accurate ship’s chronometers were perfected, navigators had to rely on repeated estimates of their speed and direction – Dead Reckoning.

Since early clocks relied on a pendulum and inferior materials, and the challenge of perfecting an accurate timepiece became apparent to me while weighing-in at Sick Bay. The roll of the ship has that up-down effect you feel in an elevator, and your weight on the scale fluctuates accordingly. (Mine swings between 165 and 225 pounds, depending on the size of the swells; so I’ll have to wait until we reach port for more accuracy.) Navigators had to wait until 1764 when watchmakers finally perfected sturdy, spring-powered and rust-resistant chronometers accurate enough to satisfy the British Admiralty to guide ships across the featureless ocean waters. Incidentally, William Harrison’s chronometer was hardly portable. It weighed 85 pounds (!).

I am going to try two experiments later. One, fashion a simply pendulum and see how the ship’s rocking affects it, and two, try some dead reckoning to determine current speed.

(Interesting coincidences: My office at work is in the shadow of Sandy Hook Lighthouse, the entrance to NY Harbor. This important beacon is the oldest continuously lit lighthouse in America – and first lighted in 1764 (!). Also, with the perfection of wireless communication;  in 1904, the US Navy established the first radio station to continuously broadcast the time for navigators to set their ship’s chronometers – at Navesink, NJ,  across Sandy Hook bay and within the sight of my office window.)

A Biologist’s Bouillabaisse

With the help of Danny, one of the ship’s engineers, I have struck gold sampling marinelife. He alerted me to the intake screen for sea water that he was removing to clear and I was able to sort through it. It is a bonanza, as you can see in the image.

Although most of the material is Sargassum weed, and some bits of plastic, there is a great assortment of material here to keep me busy for the rest of the day. I will start from the bottom. Besides the sargassum, there is other plant material swept here from shallow water. Sea grasses from around the islands support turtles and a thriving subtidal community. One colleague in Puerto Rico thinks that these meadows are as productive as an ecosystem in the ocean. Not obvious is the Aufwuchs community covering the grass blades, but under the microscope, one piece is enough to keep a class busy for hours identifying the specimens in this “fouling community.”


Bryozoa, worm tubes and coralline algae cover a slender blade of grass.


A tiny drifting animal from the surface, the Cnidarian – By-the-wind Sailor.

Perched on my fingertips, a larval crustacean ready
to drop out of the planktonic community.

A tiny larval crab viewed under the microscope (20 x’s)

An amphipod shrimp.

A Polychaete worm. One of the many annelids in the sample.
Not everyone’s favorite, unless of course, you are a fish.

Dave Grant: Horse Latitudes, February 22, 2012


NOAA Teacher at Sea

Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 22, 2012

Weather Data from the Bridge

Position:26.30 N – 75.42 W
Windspeed: 0
Wind Direction: Calm
Air Temperature: 29 C
Water Temperature: 24 C
Atm Pressure: 1025
Water Depth: 4,410 meters
Cloud Cover: 0
Cloud Type: Slight haze

Science/Technology Log:

We are becalmed and even the veteran sailors onboard are remarking on how flat the sea has become. At about 30 degrees North and South Latitude, moist, low pressure air that was heated and lifted from the surface at the Equator has cooled and is now plunging back down to Earth, forming a line of light winds in a band across the sea. This dry, high pressure air becomes the Trade winds as it is drawn back towards the Equator along the sea surface in what is called a Hadley Cell (After its discoverer). We seem to be on the edge of this meteorological milepost, which was more than a nuisance in the days of sail. If stranded in its pattern too long, food and especially drinking water became an issue, and the first to suffer would be animals being transported from the Old World to the New. Legend has it that subsequent voyagers would come across their carcasses…hence the name Horse Latitudes.

While observing ships returning to port near his home, sixteen year-old future rock star Jim Morrison (The DOORS)  composed what is perhaps his most eerie ballot – Horse Latitudes.

“When the still sea conspires an armor
And her sullen and aborted
Currents breed tiny monsters
True sailing is dead
Awkward instant
And the first animal is jettisoned
Legs furiously pumping”

However, the stable ship makes deck work easier and I am catching up on samples under the microscope, including some of my own tiny “monsters” that the currents have bred.

It is the astonishing variety of life that makes the sea such a fascinating
hunting ground. Get a tow-net, dredge and simple microscope,
and a new world is yours – a world of endless surprises.”

(Sir Alister Hardy)

The chief survey technician set me up  with his  flow-through seawater system and I can leave a net under it to continuously gather plankton. I have noticed some patterns already.
One: Phytoplankton is scarce compared to temperate waters off of New Jersey, and this helps account for the clarity and
brilliant blue color of the water. The absence of large rivers here adding nutrients to the system, and little coastal
upwelling,  means that there is little to fertilize plantlife.
Two: More accumulates in the nets at night, confirming that Zooplankton rises to the surface at in the dark. This diurnal
pattern of the plankton community has been well documented ever since biologists and fishermen went to sea.
Three: Also, there is much more plankton at the surface than in deeper water. This is no surprise since sunlight is the
key ingredient at the surface of this ocean ecosystem.
Four: Creatures from offshore tend to have a more feathery look about them than inshore species. This added surface
area may use the turbulence to help support them near the surface  and increase their buoyancy.

It is said:  “Turn off the sun, and the oceans will starve to death in a week.”  It is assumed that among other stresses on the Biosphere that accompany disastrous impacts of large asteroids, dust and ash from these rare collisions block out enough sunlight to stifle photosynthesis, causing Phytoplankton (The “Pasture of the Sea”) to waste away, and setting the stage for the collapse of the Food Chain and mass extinction events. Fortunately we have plenty of brilliant sunshine here and no celestial catastrophes on the horizon.

Some of the most interesting Zooplankton are the Pteropods, the Sea Butterflies.

   
Empty shell and live pteropod specimen
(Images on the Ron Brown by Dave Grant)

The renowned oceanographer Alister Hardy used them as indicators of different water masses flowing around the British Isles; and New England’s great oceanographer, Alfred Redfield correlated their drifting with the anti-clockwise circulation of water in the Gulf of Maine. Although most are small and less than an inch long, they feed on a variety of creatures and in turn become food for many others. In surface waters they gather phytoplankton, some utilizing cilia and mucus to sweep food to the mouth; but in deeper waters, others are carnivorous.

I am informed by our English colleagues that on Europe’s fishing grounds, they are sometimes fed upon by herring, cod and haddock; which is bad news for British fishermen, whose catch rapidly decays and is not marketable. Such fish are referred to as “black gut” or “stinkers.”

How concentrated are pteropods? Whales and seabirds that we hope to encounter later in the cruise are sustained by them, and in the warmer waters of the Atlantic, at relatively shallow depths and on the tops of submerged peaks at around 2,000 meters, R.S. Wimpenny reports considerable deposits of “pteropod ooze” from their descending shells, covering an estimated 1,500,000 square kilometers of the bottom of the Atlantic (An area the size of the Gulf of Mexico.). Like the Foraminifera, in deeper waters the aragonite in their shells (a more soluble form of calcium carbonate) dissolves, and other sediments like silicates from diatoms accumulate instead. Check out any oceanography text and you are likely to find a picture of this biogenic pteropod mud, as well as other types of deposits.

At least 90% of the animals in the ocean are meroplankton – spending time in this itinerant stage before becoming adults. This phase may vary from a few days to over a year, depending on the creature. (European eels larva are the long distance champions; for over a year, drifting from below us in their Sargasso Sea breeding grounds, all the way to rivers in Britain and France.)

Drifting larvae are cheap insurance for a species, filling the surrounding habitat with individuals of your own kind, settling in new areas and expanding ranges, and particularly, not lingering around their birthplace and competing with the parent stock. However, most individuals simply end up as food for other creatures that are higher on the food chain.

Not surprising, there are copepods, the “cattle of the sea” grazing on smaller organisms.

  
(Images on the Ron Brown by Dave Grant)

Calanus finmarchicus is sometimes called the most abundant animal in the world and is found throughout the oceans, sustaining many types of marinelife; even right whales and basking sharks off the coast of New England.

Other sea soup and children of the sea that author David Bulloch likes to call them, drift by me and swim circuits trapped by surface tension in the water drop under the microscope.

  
Radiolaria are single cell Protozoa that not only ensnare food with mucous, but harbor mutualistic algae
among their spines. (100 x’s)


More live pelagic snails. (Pteropod means winged foot.)

  
An empty shell with  copepod sheltered inside. Other skeletons filled with Paramecia, and a mixed sample of shells
and dust particles.  (Images on the Ron Brown by Dave Grant)

Now that is calm, everyone seems to have their sea legs and are comfortable talking about their bouts of mal de mer.
Here is the worst story about sea sickness I have come across:

 From Dave Grant’s collection of sea stories:
The world’s worst tale of seasickness.
As told by Ulysses S. Grant in his Memoirs

One amusing circumstance occurred while we were lying at anchor in Panama Bay. In the regiment there was a Lieutenant Slaughter who was very liable to seasickness. It almost made him sick to see the wave of a table-cloth when the servants were spreading it. Soon after his graduation [from West Point] Slaughter was ordered to California and took passage by a sailing vessel going around Cape Horn. The vessel was seven months making the voyage, and Slaughter was sick every moment of the time, never more so than while lying at anchor after reaching his place of destination. On landing in California he found orders that had come by way of the Isthmus [Panama], notifying him of a mistake in his assignment; he should have been ordered to the northern lakes. He started back by the Isthmus route and was sick all the way. But when he arrived back East he was again ordered to California, this time definitely, and at this date was making his third trip. He was sick as ever, and had been so for more than a month while lying at anchor in the bay. I remember him well, seated with his elbows on the table in front of him, his chin between his hands, and looking the picture of despair. At last he broke out, “I wish I had taken my father’s advice; he wanted me to go into the navy; if I had done so, I should not have had to go to sea so much.”

Poor Slaughter! It was his last sea voyage. He was killed by Indians in Oregon.

Dave Grant: Terra Nova, February 13, 2012

NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 13, 2012

Weather Data from the Bridge

Position: 26.30N Latitude – 71. 55W Longitude
Windspeed: 15 knots
Wind Direction: South (bearing 189 deg)
Air Temperature: 23.2 C / 74 F
Atm Pressure: 1013.9 mb
Water Depth: 17433 feet
Cloud Cover: 30%
Cloud Type: Cumulus

Personal Log

After an uneventful flight from New Jersey and an eventful trip from the airport at Charleston and through security at the naval base (Taxi drivers don’t like to have their vehicles inspected…), I am setting up my bunk on the Brown. There is a skeleton crew since I have arrived early and everyone else is expected to report tomorrow. Crates of equipment are still being loaded, so it is advisable to stay off the outside decks, and after a quick orientation by every  ship’s most important crew member (the chef),  I will have the evening free to find my way around the ship and explore the dock.
First order of business: Pick up bedding from the laundry down below.
Next: PB&J sandwich (Since the galley doesn’t open until tomorrow).
Finally: Grab the camera to catch the sunset and an amazing assortment of cloud types.

South Carolina’s estuaries are noted for their fine “muff” mud and oyster banks and the tideline at the docks is covered with a dense ring of oysters. Besides filtering great quantities of water and improving its quality, oyster “reefs” provide a secure habitat for a myriad of marinelife, and food for many creatures. (As a frustrated oyster farmer in South Jersey once remarked: “There ain’t much that lives in the ocean that doesn’t like to eat oysters!”)

This is a working dock so access is limited but before it got dark I was able to get close to the waterline at low tide and look for crabs, anemones, sponges, worms and other invertebrates – members of what the boaters consider the “fouling” community when it gets established on the hull.
Anything immersed in the water for more than a few months becomes habitat for oyster spat recruitment. One method of raising them is to suspend them from lines, which helps isolate the from predatory snails and sea stars.
There are small fishes around too, but I could not get more than a glimpse of them. However, some waterbirds are around and they are always proof that food is available too. The most abundant are cormorants. Although their Latin name (Phalacrocorax ) translates as “crow of the sea” the only shared features with crows are dark feathers and an occasional guttural squawk. They roost on the ends of the pier “hanging out” – quite literally. Lacking much of the oil that keeps other birds dry – when not diving for fishes, they spend a considerable amount of time spreading their wings to dry so they can fly.

The prettiest bird around is the red-breasted merganser, another diving fish eater. Hunters nicknamed mergansers “saw-bills” since their bills have tooth-like notches for snaring fishes. The word merganser comes via Latin mergere meaning “diver” and “to plunge.” Curiously, one of my favorite students always mixes up the word and somehow it comes out as Madagascar (!).

(Images on the Ron Brown by Dave Grant)

The most secretive and uncommon bird around the piers is the pied-billed grebe. It also dives for its dinner, but on the bottom. When frightened (or pestered by a photographer trying to get close in the fading light) it discreetly sinks straight down and disappears like a submarine. Locally, this trick earned the grebe the nickname water witch, and by Louisiana sportsmen Sac de plomb (bag-of-lead).

By far the noisiest birds around and the only ones onboard, are boat-tailed grackles. The iridescent, purple-black males are hard to ignore when gathering for the night on our upper rigging. A common bird of Southeastern marshes; since the 1960’s boat-tails have been expanding their range north along the Eastern seaboard beyond Delaware Bay, and now breed all along the New Jersey coast. (A normal extension of their population, or perhaps a response to warming climate? Time will tell.)

Just before dark a peregrine falcon surprised me as it glided past the ship – undeniably the most exciting sighting of the day and a great way to end it.

 “Oh end this day,
show
me the ocean.
When shall I see the sea.
May this day set me in emotion
I ought to be on my way”
(James Taylor)

Dave Grant: The Ship Was Cheered, the Harbor Cleared…, February 15, 2012

 NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 15, 2012

Weather Data from the Bridge

Position: Windspeed: 15 knots
Wind Direction: South/Southeast
Air Temperature: 23.9 deg C/75 deg F
Water Temperature: 24.5 deg C/76 deg F
Atm Pressure: 1016.23 mb
Water Depth: 4625 meters/15,174 feet
Cloud Cover: less than 20%
Cloud Type: Cumulus

Personal Log

Crew and scientists are reporting for duty and everyone is to be onboard by sunset for a scheduled departure tomorrow morning. There are many boxes of equipment to unload and sampling devices to assemble, so everyone is busy, even during meal times.

Tall ships had miles of rope and lines for handling enormous amounts of sail.
The Brown is also carrying miles of line and cable too, but not for sailing. This is coiled neatly on reels and will be used to anchor moorings of monitoring equipment that will record water temperatures and salinities for an entire year until they are recovered on the next cruise. These moorings are anchored with ship recycled chain and old railroad wheels and their long lines of sensors rising to the surface from 5,000 meters form the electronic “picket fence” spaced between Florida and Africa across the 26.5 degree North Latitude line we are sailing.

On our last night ashore we went downtown to enjoy dinner at one of the many nice restaurants in the historic district. It was a good time to update each other on different projects and make any last minute purchases. Everyone is anxious to get started. As captains like to say:

 “Ships and sailors rot at port.”
(Horatio Nelson)

Day 3 
We are leaving the dock on schedule and heading down river.

Old sailors’ superstitions say that a small bird or bee landing on the deck of a departing vessel foretells good luck on a voyage, and a tangled anchor line forecasts bad luck. Glancing around, I observe our noisy grackles preparing to depart neighboring ships at dock –  so I hope they qualify as small birds. And huddled out of the wind on deck is a crane-fly – not a bee, but a harmless bug that looks like a giant mosquito. Perhaps no guarantee of good luck, but since all our lines and chain are neatly stowed, I am confident that an old “salt” – seeing how ship-shape the Brown is – would concur that we shouldn’t unnecessarily envision any bad luck on our cruise.

Cranefly

Dolphin "X"

Sailing down river we receive a great treat and are guided to the sea by small groups of dolphins surfing underwater in our bow wave. These are Tursiops – the bottle-nosed, the most common and well-known members of the dolphin family Delphinidae. Tursiops is Latin for “dolphin-like.”  Their comradeship is another reassuring sign of good luck to suspicious sailors. It is a remarkable spectacle and entertainment to everyone, even the veteran crew members, who, like the ancient mariners, have reported it many times. Although they seem to be taking turns at the lead, one dolphin that keeps resurfacing has a small cross-shaped scar on the port side (Left) of the blowhole; proving that at least one member of the pod has kept pace with us for the entire time.

Ship mates. (Images on the Ron Brown by Dave Grant)

Curiously, they know to abandon us near the river mouth to join other “bow riders” that have caught the wave of a freighter that is entering the river and heading upstream. Noteworthy is the bulbous bow protruding in front of the freighter. Reminiscent of the bottle nose of a dolphin, the bulb modifies the way the water flows around the ship’s hull, reducing drag – which increases speed, range, fuel efficiency and stability – things dolphins were rewarded with through evolution. And what a show the dolphins make riding the steeper bow wave! Actually launching out of the vertical face of it like surfers.

Bow rider!

Passing historic Ft. Sumter we receive an impromptu lecture by some of the crew on Charleston’s rich history from the days of Blackbeard the pirate, up through the Civil War. There is an interesting mix of people on board, from several countries and with extraordinary backgrounds. There is also a great assortment of vessels using the bay – freighters, tankers, tugs, patrol boats, cranes, sailboats and a huge bright cruise ship. I am reminded of Walt Whitman’s Song for All Seas, All Ships:

Of ships sailing the seas, each with its special flag or ship-signal,
Of unnamed heroes in the ships – of waves spreading and spreading
As far as the eye can reach,
Of dashing spray, and the winds piping and blowing,
And out of these a chant for the sailors of all nations…

        

     

 I note a transition here from the river to bay ecosystems reflected in the birdlife observed. Grebes and mergansers are replaced by pelicans and gulls.

The bay mouth is protected from wave action by low rip-rap jetties, and outside of them in a more oceanic environment are loons, scoters, and our first real seabirds – northern gannets. Loons spend the summer and nest on pristine northern lakes like those in New Hampshire (Reminding me of the movie On Golden Pond) but migrate out to saltwater to winter in ice-free coastal areas.

Scoters (Melanitta) are stocky, dark sea ducks that winter over hard bottoms like the harbor entrance, where they can dive down and scrape mussels and other invertebrates from the rocks and gravel.

Gannets are cousins of the pelicans but much more streamlined. They too dive for food but from much greater heights, sometimes over 100’. They also plunge below the surface like javelins to snare fishes. They are wide-ranging visitors along the East and Gulf coasts, wintering at sea, and returning to isolated cliff nesting colonies known as a “gannetry”  in Maritime Canada

The ship was cheered, the harbor cleared,
Merrily did we drop,
Below the kirk, below the hill,
Below the lighthouse top.

(Coleridge)
 Sullivan Island lighthouse
Latitude: 32.75794
Longitude: -79.84326

The odd triangular shaped tower of Sullivan Island lighthouse originally had installed the second brightest light in the Western Hemisphere. (Said to be so powerful that keepers needed to wear asbestos welding gear when servicing the light)
At 163 feet, its unusual flash pattern is tricky to catch on camera, but it is our last visual link to the mainland, and it will be the only land feature we will see until we are off the lighthouse at Abaco, Bahamas, after ten days at sea. A lighthouse keeper at the lens room, watching us sail away, could calculate at what distance (in miles) we will disappear over the horizon with a simple navigator’s formula:

The square root of 1.5 times your Elevation above se level.
Try it out:  √1.5E’ = _____ Miles 

√1.5 x 163′  = _____ Miles  to the horizon

(Images on the Ron Brown by Dave Grant)
 

Dave Grant: Going “Blue Water”
, February 17, 2012

NOAA Teacher at Sea
Dave Grant
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: February 17, 2012

Weather Data from the Bridge

Position: Windspeed: 15 knots
Wind Direction: South/Southeast
Air Temperature: 23.9 deg C/75 deg F
Water Temperature: 24.5 deg C/76 deg F
Atm Pressure: 1016.23 mb
Water Depth: 4625 meters/15,174 feet
Cloud Cover: less than 20%
Cloud Type: Cumulus

Science/Technology Log

Sailors used to describe their trips as short-haul or coastal,
or “long seas” which also was described as going “Blue Water”


We are off to a great start after passing the harbor lighthouse and breakwater, and the seas are calm and winds gentle. The Low Country and barrier islands of South Carolina disappear quickly over the horizon, and the most striking change for me is the color of the water. As we have transited from the sediment rich waters upriver, to the estuary, and out to the ocean, its color has gone from grayish, to green to blue.

Bay/Estuary water in Charleston

Gulf Stream water

As a rapid indicator of what’s going on within it biologically, oceanographers use the color of the water. To quantify their observations for other scientist to compare results, a white secchi disc is lowered just below the surface and the observer compares the ocean’s color with tinted water in a series of small vials – the Forel-Ule Scale. (Francois Forel was an oceanographer and his end of the scale is the bluest; and Willi Ule was a limnologist and his end of the scale is darker, reflecting the fresh waters he studied.) The 21 colors run the gambit of colors found in natural waters and modified by the plankton community and range from brownish-to-green-to-blue. This gives you a quick measure of productivity of the waters and the types of phytoplankton predominating. For example: Diatom blooms are brownish and Dinoflagellate blooms form the notorious red tides. Clear, less productive waters look blue, and we are sailing into waters that are a deeper blue with every league we sail.

I lack a secchi disk and we can’t stop the ship to lower one anyway, so I am using instead a scupper on the side as a photographic frame to document this well-studied and interesting phenomenon.

“Being on a boat that’s moving through the water, it’s so clear.
Everything falls into place in terms of what’s important, and what’s not.”
(James Taylor)

Before departing on the trip I came across Richard Pough’s bird map of the Atlantic. On it he divides the ocean into 10-degree quadrants and indicates the average water temperature and number of birds he sighted daily. The good news is we are heading southeast into warmer waters. The bad news is, he does not indicate a very productive hunting ground for bird watching. For example, Cape Hatteras, NC, where the Gulf Stream skirts North Carolina, shows 40 birds. Off the highly productive sub-polar regions like Iceland where there are great breeding colonies of seabirds like gannets, he indicates scores of birds. Regardless, I am hopeful we will find some true seabirds to photograph on our voyage; and perhaps have some migrating songbirds drop in for a rest.

Gulf Stream sunset

Today, as our colleague Wes Struble discusses on his blog, we retrieved our first samples with the CTD rosette. Water is retrieved from predetermined levels between the surface and 4,500 meters sealed in bottles for salinity and dissolved oxygen analysis. These two physical features, along with temperature, are the benchmarks physical oceanographers rely upon to track the ocean circulation.

For an understanding of this process and an overview of the project, I met with Molly Baringer in her office – a large bench that the ship’s carpenter built on deck. It seats three and is similar to a lifeguard stand, so it can give a view of the water and fit over the [dis]array of equipment constantly being shifted around the fantail by various scientists and deck hands. With the calm seas and sunny weather, it is the perfect spot on the ship to sit with a laptop to outline daily assignments for all of us, review the mass of data streaming in, and relax to watch the sunset.

“When I am playful,
I use the meridians of longitude and parallels of latitude for a seine,
and drag the Atlantic Ocean for whales!”

Mark Twain

Scientists and crew prepare to retrieve a mooring before the next big wave!

Chief scientist Dr. Baringer is a physical oceanographer and so is interested less in the creatures moving around in the ocean and more about the water currents that are moving them around, and particularly the vast amount of heat that is transferred from the Equator to the Polar Regions by “rivers in the sea” like the Gulf Stream.

 Currents and storms in our atmosphere produce our daily weather patterns, which of course change seasonally too. Ocean currents work on a much longer time scale and the text book example of the turnover time of warm water moving Pole-ward, cooling and returning to the Tropics as “centuries.” This timeframe infers that dramatic fluctuations in climate do not occur.

However, by analyzing ice cores from Greenland, scientists recently have detected evidence of abrupt changes in climate – particularly a significant cooling event 8,200 years ago – that could be associated with vacillations in the Gulf Stream. Although lacking a blackboard at her impromptu lecture hall on deck, a patient Dr. Baringer was artful in walking me through a semester of climatology and modeling to highlight the implications of an oscillating Gulf Stream and its deepwater return waters – the Deep Western Boundary Current.

Surface water is driven from the southern latitudes towards the Poles along the western side of the Atlantic, constantly deflected in a clockwise pattern by the Earth’s rotation. Bathing Iceland with warm and saltier water and keeping it unusually mild for its sub-polar latitude, the Gulf Stream divides here with some water flowing into the Arctic Sea and the rest swirling down the Eastern Atlantic moderating the climate in Great Britain, France and Portugal. (This explains the presence of a rugged little palm tree that I once saw growing in a Scottish garden.)

Perturbations in the northward flow of heat by meanderings of the Gulf Stream or the smothering of it of it by lighter fresh waters from melting ice in Greenland and Canada appears play a significant role in occasionally upsetting Europe’s relatively mild and stable climate – which is bad enough. What is more alarming is new evidence that these changes don’t necessarily occur gradually over centuries as once assumed, but can take place rapidly, perhaps over decades.

There is more bad news. The surface of the sea is dynamic and even without wind and waves, there are gentle hills and valleys between areas. I remember my surprise when our physical oceanography teacher, Richard Hires, pointed out that because of warmer water and displacement by the Earth’s rotation, Gulf Stream waters are about a meter higher than the surrounding ocean…that to sail East into it from New Jersey, we are actually going uphill. If these giant boundary currents are suppressed in their movements, it will exasperate an ongoing coastal problem as those hills and valleys of water flatten, resulting in rising sea levels and erosion along northern coastlines.

This explains why we are “line sailing” at 26.5 North, sampling water and monitoring sensors arrayed on the parallel of latitude between Africa and the Bahamas. To measure change, it is necessary to have baseline data, and the stretch of the Atlantic is the best place to collect it.

Snap shots of the water column are taken using the CTD apparatus as we sail an East-West transect, but at $30-50,000. Per day for vessel time, this is not practical or affordable. Here is where moorings, data recorders and long-life Lithium batteries come into play. By anchoring a line of sensors in strategic locations and at critical depths to take hourly readings, year-long data sets can be recorded and retrieved periodically. Not only does this save time and money, it is the only way to generate the ocean of data for researchers to analyze and create a model of what is happening over such a vast region – and what may occur in the future.

For more specific details, check out the project overview.

Deep Western Boundary Current Transport Time Series to study:
-the dynamics and variability of ocean currents;
-the redistribution of heat, salt and momentum through the oceans;
-the interactions between oceans, climate, and coastal environments; and
-the influence of climate changes and of the ocean on extreme weather events.
Information at:  http://www.aoml.noaa.gov/phod/wbts/ies/index.php

We hear that “The package is on deck” and it is time to collect water samples from the 24 different depths the Niskin bottles were fired (Remotely closed). As any aquarist will assure you, as soon as seawater is contained it begins to change, so we always start with the bottom water and work around to the top water since dissolved oxygen levels can drop with rising temperatures and biological activity from planktonic creatures trapped along with the water samples.

Although as oceanography students we read that most ocean water is quite cold (~3.5C)  because only the top 100 meters soaks up the warmth from sunlight, it is still an awakening for me to fill the sample bottles with even colder bottom water. After a half hour of rinsing and filling bottles, my hands are reminded of the times I worked in an ice cream parlor restocking containers from the freezer and filling soft-serve cones. It is a delight to get to the last several bottles of warm (25C) surface water.

Once the DO and salinity bottles are filled, they are removed to the chemistry lab and the Niskins are all mine. By holding a small plankton net under them as they drain excess water, I try my luck at catching whatever has almost settled to the bottom. There is an extra bonus too. A patch of floating Sargassum weed that tangled in the rosette was retrieved by the technician and set aside for me to inspect.

Windrows of Sargassum weed drift past the Ron Brown

Here is what I found under the microscope so far:

From depth:

The bottom water is absolutely clear with no obvious life forms swimming around. However a magnification of 50x’s and the extra zoom of my handy digital camera set-up reveals a number of things of interest I am sorting into AB&C’s:
Abiotic: Specks of clear mineral crystals. Are these minute sediments washed from the mainland or nearby Caribbean islands? Or is it possible they are quartz grains carried from much greater distances, like the Saharan dust that satellite images have proven are swept up by desert winds and carried all the way across the Atlantic?

Biotic: Although I can not find anything living, the silica dioxide skeletons (frustules) of at least two species of diatoms are present. These fragile fragments of glass accumulate in deep sediments below highly productive zones in the sea and different species are useful to paleontologists for determining the age of those deposits. On land, fossil diatom deposits are mined for diatomaceous earth – used as an abrasive and cleaner, pool filter material, and even in nanotechnologyresearch applications. There is other detrital material in the samples, but nothing identifiable.

Celestial(?): One tiny round particle caught my attention under the microscope. It looks like the images I’ve seen of microtektites – glassy and metallic meteor particles that have been molded by the heat of entry into the atmosphere. The Draxler brothers, two science students in Massachusetts, collect them and I hope they will confirm my identification when I see them again.

Dust particle (Right) and foraminifera (Center)

From the surface:

The warm, sunlit surface water here is covered with Sargassum weed, a curious algae that sustains an entire ecosystem in the waters mariners named the Sargasso Sea. On board the Brown it is simply called “weed” in part because it can be a minor nuisance when entangled with equipment. The Sargassum’s air bladders that support it at the surface reminded Portuguese sailors of their sargazagrapes and they named the gulfweed after them.

Can you spot the two Sargassum shrimp next to the air bladder?

Floating Sargassum weed harbors a great variety of other creatures including baby sea turtles, crustaceans and especially bryozoan colonies. The film of life encrusting the weed is sometimes called aufwuchs by scientists and is a combined garden and zoo.

A quick rinse in a plastic bag revealed two species of bryozoan and numerous tiny crustaceans. The Phylum Bryozoa is the “moss animals” a puzzling colonial creature to early biologists. Bryozoans are an ancient group with a long fossil record and are used by paleontologists as an “index” species to date sediments.

Byozoan colony

To my delight there were also some foraminifera in the samples. “Forams” as they are called by researchers, are single celled protozoa with calcium carbonate skeletons. They are abundant and widespread in the sea; having had 330 million years to adjust to different habitats – drifting on the surface in the plankton community and on benthic habitats on the bottom.

It is not necessary for you to go to sea with a microscope to find them. I have seen their skeletons imbedded in the exterior walls of government buildings in Washington, DC; and our own lab building at Sandy Hook, NJ has window sills cut from Indiana limestone – formed at the bottom of the warm Mesozoic seas that once covered the Midwest. In the stone, a magnifying glass reveals pin-head sized forams cemented among a sea of Bryozoan fragments. Some living forams from tropical lagoons are large enough to be seen without a magnifier, and  are among the largest single-celled creatures on the planet. With a drop of acid (The acid test!) our Geology students confirm that our window sills are indeed made of limestone as the drops fizzing reaction releases carbon dioxide sequestered when the animal shell formed.

Living foraminifera eat algae, bacteria and detritus and are fed upon by fishes, crustaceans and mollusks. Dead forams make contributions to us by carrying the carbon in their skeletons to the bottom where it is sequestered for long geological periods.

Geologists also use different species of forams as “index” species to fix the date of strata in sediment cores and rocks. The appearance and demise of their different fossil assemblages leave a systematic record of stability and change in the environment; and paleoclimatologists use the ratios of Carbon and Oxygen isotopes in their skeletons document past temperature ranges.

Our first plankton samples extracted from the deepest samples retrieved from the Niskin bottles at 4,000 meters (2.5C) did not produce any forams. This may be because in deep, cold water, calcium carbonate is more soluble and the skeletons dissolve. Presumably why we identified only the glassy tests of diatoms.

Foraminifera shell at 100x’s

Tiny Paramecia swarm over the detritus in my slide and taking a closer look at that and the growth associated with the weed I am reminded of Jonathon Swifts jingle:

Big fleas have little fleas
Upon their backs to bite ‘em
And little fleas have lesser fleas

And so, ad infinitum 


Sunset over the Sargassum Sea

The Chief Scientist:

A day in the life of our chief scientist involves: checking with her staff to evaluate the previous day’s collections, consulting with visiting scientists on their needs and any problems that might arise, checking with the deck hands and technicians about equipment needs and repairs, advising the ship’s officers of any issues, and making certain we are on course and schedule for the next station.

And then rest? Hardly!

Even when off duty there are inquiries to field from staff, scientists and crew; equipment repairs to be made; and software that needs to be tweaked to keep the data flowing.

How does one prepare for a career like this?
Physically: the capacity to function on little sleep so you can work 12-hour shifts and be on-call the other twelve. (And there is little escape at mealtimes either, where the conversation never stays far from the progress of the cruise.)Mentally: the capability to multi-task with a variety of very different chores.
Emotionally: the flexibility to accommodate people with many different personalities and  needs, while staying focused on your own work.
Also, excellent organizational skills, since months of planning and preparation are crucial.
And perhaps most importantly, a sense of humor!

 

 “Lock-and-Load!
Midnight shift.
Chief Scientist Dr. Molly Baringer prepares to fire the XBT
off the stern for an 800 meter profile of temperature and pressure.