Wetlands

Tom Bianchi blogs from field work in the Louisiana wetlands and marshes
Tags >> marshland

Today we sampled the contaminated marshes which, in fact, appear to represent a relatively small fraction of the total marshes we observed in these regions of Barataria Bay.

Contamination of the marsh grassesPhoto right: marsh death behind the oil booms in Barataria Bay

As you can see in the photo there was significant marsh death in the oiled regions, however we already see new shoots of marsh plants beginning to occur.  Assistant Professor Alex Kolker from LUMCON, noted these new shoots of Spartina plants beginning to occur in these contaminated areas. While this is very encouraging in terms of marsh recovery, the amount of suspended particulates was considerably higher. Filtered water had a distinct oil smell which will likely result in higher dissolved organic matter concentrations, that can potentially allow bacteria to transfer these hydrocarbons to higher trophic levels in the marsh. 

This remains to be determined over the next few weeks as data is gathered at Texas A&M (Thomas Bianchi lab), LSU (Rob Cook lab), and Georgia Tech (Michael Perdue lab). 

Louisiana Fisheries and Wildlife research stationTomorrow, we will sample another contaminated site and then make our way back to LSU where the dissolved organic matter will be concentrated using reverse osmosis electrodialysis.

(Photo right: Louisiana Fisheries and Wildlife research station)

Overall, the fish activity, bird life and even crabs in the marshes seem more active that expected in the contaminated regions. Nevertheless, if the tissues of these animals continue to accumulate hydrocarbons that could impact higher trophic levels.   The graduate students at LSU (Paulina Kolic), Georgia Tech (Nelson Green and Yaoling Zhang), and LUMCON (Alex Ameen) have all been working diligently in sampling many thousands of liters of water from these sites.

Tomorrow, we do it again.


The plan is for us to mobilize to Baton Rouge on Thursday so that we can all take a HazMat course at Louisiana State University (LSU), which will then be followed by our driving to Grand Isle, Louisiana, on Thursday evening (July 14th) to prepare for sampling in the marshes of Barataria Bay on Friday morning.  This sampling effort will involve sampling at two oil contaminated and two "clean" sites  where we will measure oxygen, pH, and filter numerous liters of water.  We will likely sample two sites per day since thousands of liters of water need to be collected, we will be sampling from a 10 m long boat rented from Louisiana Universities Marine Consortium (LUMCON). 

There will be two graduate students of Co-PI Michael Perdue from Georgia Tech (Nelson Green and Yaoling Zhang) who will be responsible for the reverse osmosis-electro-dialysis (RO/ED) work. They will concentrate dissolved organic matter (DOM) by removing all the salts.

oil in wetlands - National Geographic photoRobert Cook (Co-PI) and his graduate students (Paulina Kolic)  from LSU will also participate in the sampling but will largely be responsible for solid-state carbon nuclear magnetic resonance spectroscopy (13C-NMR), fluorescence, and UV-FTIR analyses of the DOM samples.

Oil in the marshlands (photo by National Geographic)

Alex Kolker, a scientist from LUMCON, and expert of marsh ecosystems will also collaborate with this team in getting samples from the marshes. 

Once we have collected approximately 4000 L of water we will transport this water in a refrigerated truck to LSU where the DOM will be stored in large cold rooms and then concentrated using RO/ED over the next two weeks.  Once this DOM has been concentrated, samples will be sent to the Cook, Perdue, and Bianchi labs for chemical characterization of this material to determine differences between "clean" and contaminated sites.  This information will allow us to assess how the decomposition of dying marshes affects the composition of DOM in the marshes, which represents an integrative index of the "health" of many ecological processes involving plants, animals, and bacteria.  these early chemical signatures of marshes hat have impacted will be critical in determining the long-term effects of oil contamination on Louisiana marshes. 

Photographs from National Geographic. This project is funded by NSF, Chemistry Division, Environmental Chemical Sciences.

 


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