NOAA Teacher at Sea
Onboard NOAA Ship Ronald H. Brown
September 25 – October 22, 2005
Mission: Climate Observation and Buoy Deployment
Geographical Area: Southeast Pacific
Date: October 18, 2005
Weather Data from Bridge
Temperature: 25.5 degrees C
Clouds cover: 6/8, stratus, altocumulus
Visibility: 12 nm
Wind direction: 245 degrees
Wind speed: 13kts.
Wave height: 3 – 5’
Swell wave height: 3 – 5’
Seawater Temperature: 28.7 degrees C
Sea level Atmospheric pressure: 1005 mb
Relative Humidity: 82%
Science and Technology Log
Rodrigo Castro and Carolina Cisternas are research technicians from the University of Concepcion in Concepcion, Chile. They joined the cruise at Panama City and have been taking ocean water samples every 60 nm. Their samples are run through 0.7 and 0.2 micron filters. They capture and freeze particulate organic mater by this process and take it back to the lab at the university. The samples are analyzed for the presence of stable isotopes of carbon and nitrogen. These samples are then used as biomarkers to help determine the circulation of ocean water. A second analysis will be going on to locate the gene associated with nitrogen-fixing organisms. This is new ground for the scientists at the university.
Upwellings are areas where deep ocean water comes to the surface. According to Rodrigo and Carolina there are four significant areas of upwelling along the Chilean coast. The two most northerly are found at 20 degrees south and 24 degrees south. These are active year round and are slow and steady with no significant seasonal fluctuation. Another at 30 degrees south is moderate in nature with some seasonal variation, being more active during the summer. The most southerly is at 36 degrees south and is strong September to April. However it mostly disappears the rest of the year. Upwelling zones are recognizable because of their cooler water temperature. They also have increased nutrients that are brought up from the deep and a higher amount of chlorophyll due to increased photosynthetic activity. Some fish species are found in greater abundance in these zones due to increased nutrients extending into more food availability.
The RONALD H. BROWN is under way. We are steaming in an easterly heading on the leg of the cruise that will take us to Arica, Chile. It is a bit of a challenge for me, as we are no longer headed into the direction of the swells; instead, we are crossing them at a 30-degree angle, which makes for more oscillations in the movement of the ship. My tummy is being challenged.