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Collaborating on the Continuum

06/18/2010, 8:21 PM by Lollie Garay
Victoria measures salinity in samples.<br/><br/>Credit: lollie Garay
Victoria measures salinity in samples.
Photo Credit: lollie Garay

June 18
Lat/Long: 11.16N 056.34 W
Air Temp: 28.5C 83.3F
Surface Temp: 29.5C 85.2F

The days are numbered for this cruise, and I am still trying to get everyone onboard acknowledged. A series of events have slowed my progress but I hope to make up for it in the next couple of blogs!

If you’ve read through the different portions of the Amazon continuum website, then you may have seen information about “ROCA” (the River-Ocean Continuum of the Amazon). The ANACONDAS and ROCA teams are working together to study the continuum of the Amazon River as it flows into the ocean (the plume). Our focus on the RV Knorr has been on the oceanic plume, where the freshwater river empties onto the ocean. Others from the ROCA team will be working up in the river itself later this summer.

ROCA is trying to understand the transformation of nutrients and carbon by microorganisms as they move from the land to the sea by way of the Amazon River. Processes on land can affect what happens in the ocean. Those effects may impact carbon sequestration and have a feedback on climate. Working with the ANACONDA team, ROCA will examine these transformations along the continuum with greater detail than was possible by ANACONDAS alone.

According to Dr. Victoria Cole (University of Maryland, Center for Environmental Studies), researchers found out 8 years ago that the Amazon Plume was taking up a lot of atmospheric carbon and getting rid of it by sinking it to the deep ocean (the biological pump). We think that certain phytoplankton communities (DDAs), responsible for this carbon pumping, thrive in the conditions of the plume. Dr. Cole added that we are able to identify the factors that contribute to this process, but they can’t figure out how it all works or how it might be sensitive to climate change.

The team of ROCA researchers is represented onboard the RV Knorr by graduate student Brian Zielinski (USF,Tampa), Dr. Patricia Medeiros (UGA), Dr. Marcelo Fernandes, Dr. Victoria Coles (UMCES), and Dr. Patricia Yager (UGA). Brian works with Dr. John Paul (USF, Tampa), who is looking at the gene expression in eukaryotic phytoplankton. Brian is also collecting a parallel set of samples for Dr. Mary Ann Moran (UGA), who is studying bacterial and archael gene expression, and for Dr. Byron Crump (UMCES) who will example the microbial community composition using DNA. All three labs are working collaboratively on this portion of ROCA.

Patricia Medeiros and Marcelo Fernandes are investigating how the organic material found in the plume is linked to land and soil processes.

Brian’s onboard duties include collecting and filtering seawater from 3 m. He uses fifteen 142mm filters which are then saved in a nucleic acid stabilization liquid. The filters will be used to extract DNA and RNA back in the states. He is also using a Flow Cytometer to prepare water for counting viruses. Marine viruses don’t make people sick, but they can make plankton sick, which impacts the performance of the biological pump.

Their collective work will help them to understand some of the dynamics of the communities and their role in the continuum.


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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.