We Blogged It!
Lat/Long: 08.17N 050.45W
Air Temp: 28.2C 82.76F
Surface Temp: 29.31C 84.76F
We’re now past the halfway point of our journey and work continues ‘round the clock.
There are some underway samples being collected as we transit between stations. The “underway” is collecting information on pigment types of phytoplankton communities, suspended particle samples, nutrient concentrations, and measures Carbon, Nitrogen and Carbon and Nitrogen stable isotopes.Added to that are the usual CTD casts, plankton net tows and sediment cores and traps, and the hours of filtering, processing, and running experiments.
But in spite of this 24 hour schedule we‘ve managed to carve out some time for fun. So ....how about a water balloon fight on the fantail! The winner of this water battle?- depends on who you ask! It didn’t last long but brought a welcome change to the day!
Wondering where I was? Two of us were smart enough to walk out with cameras declaring journalistic immunity!
But back to the business of science. At the start of the cruise an ARGO float was deployed in the plume waters. The float was programmed to move up and down (to 1000m) in the plume waters to provide us with near-real time vertical profiles of Salinity, Temperature and Oxygen. A special set of sensors are incorporated into the float that provide us with measurements of fluorescence (a index of phytoplankton biomass) and of particle backscattering. The data sets from the float will aid us in understanding the evolution of plume phytoplankton communities and their fate of plume following active growth and demise.
The ARGO float is one part of the work being conducted by Dr. Joaquim Goes from the Bigelow Lab in Boothbay Harbor, Maine. Dr. Goes’ team includes Research Scientist Dr. Helga Gomes (Bigelow Lab), and student Courtney Beaulieu (Colby College,Waterville, ME).
The focus of their research is to understand how the Amazon River plume influences sunlight penetrating into the water. This is important since phytoplankton in seawater depend on solar radiation as their energy source for photosynthesis and growth.
Dr. Goes explains: “The outflow of freshwater from the Amazon River is the largest of all the world’s rivers. Every second, the Amazon river empties around 120,000 cubic meters of freshwater into the western Atlantic Ocean, a rate that is roughly seven times higher than that of the Mississippi. Because the Amazon River flows through the world’s biggest and most densely forested river basins, it carries with it massive amounts of sediments, nutrients as well as particulate and dissolved organic material which together impart a unique color to the freshwater being discharged, making it visible from space as a greenish-brown plume stretching several thousands of miles in the western north Atlantic Ocean.”
All of these river components (light, nutrients, dissolved organic matter, salinity, temperature, etc) change as water moves along the river continuum and the water mixes with the ocean. These changes then have a profound influence on the composition and magnitude of phytoplankton communities within and outside of the plume.
Over the course of the cruise they are deploying several optical instruments to map the underwater light field within and outside the plume. A favorite of the crew is the “FRRF” (pronounced “ferf”). This underwater profiling Fast Repitition Rate Fluorometer, along with laboratory based “photosynthetrons” and spectrophotometers, will be used to investigate how actively the phytoplankton can respond to light. How “ready” are they to grab any light that comes by.
With the help of an underway Advanced Laser Fluorometer (ALF), they are also monitoring the diversity, size and structure of phytoplankton communities by measuring the presence of certain phytoplankton pigments. This will help us to understand how to interpret the ocean color that satellites see from space.
As I post this blog, we are rocking and rolling as we sail straight into the Northeast trade winds. The ship lurches as we meet the waves head on. It’s a bumpy ride tonight!!!
Question of the Day
- Do the bacteria in the water make us sick?
Only a few of them. Bacteria are in every habitat on Earth, growing in soil, hot springs, radioactive waste, water, as well as in organic matter and the live bodies of plants and animals. Bacteria recycle nutrients, with many steps in nutrient cycles depending on these organisms, such as nitrogen fixation.