Wednesday, May 28, 2014

Domoic Acid in the Phyto's

To say that I'm learning a lot would be a gross understatement. I'm drinking scientific knowledge from a firehose here. Every day and night, our conversations with the brightest and best scientists, experts in multiple disciplines from biology to chemistry to geology, supersede my limited knowledge of the marine world. Little by little, my understanding grows. How do you eat an elephant? One bite at a time. 

Dr. Cochlan (SFSU-RTC) with former student, Brian Bill (NOAA-NWFSC),
enriching seawater for a domoic acid experiment.
The way research cruises work is that the principal investigators collaborate ideas, plan, and write a grant proposal to fund a specific investigation. In our case, Dr. Bill Cochlan was selected to be the chief scientist by the group. They then sent a proposal to the National Science Foundation (NSF) that was accepted relatively quickly due to its uniqueness and importance. Normally, these proposals will take several drafts, but because of the urgency of field data to monitor effects of oceanic acidification (OA) on lipid quality and quantity on the only marine organisms responsible for their production--effecting the entirety of the marine food web, their proposal was accepted and funded on the first submission. After the proposal and budget is approved, Dr. Cochlan and his team not only begin the hard work of planning and testing for the target experiments on board but continue to reach out to other noted marine scientists to coordinate experiments that will compliment this target research. Therefore, many peer-reviewed publications of the past and the future will have repeating names as authorship: Dr. Wells (U. Maine), Dr. Trick (Western U.), Dr. Trainer (NOAA-NWFSC), Dr. Bidigare (U. Hawaii) and Dr. Cochlan (RTC-SFSU). Every group benefits independently from the use of the research vessel, gathering data from otherwise unaccessible waters without this great lab at sea, but they all benefit cooperatively by the sharing and comparing of data.

One of the complimentary groups that is adding to the overarching goal of this sea-faring excursion is NOAA (National Oceanic and Atmospheric Administration). Through the leadership of Dr. Vera Trainer, who I will be writing a post about specifically later, NOAA's Northwest Fisheries Science Center has partnered with Dr. Cochlan and San Francisco University's Romberg Tiburon Center for years to collaborate and present the most honest picture of the ocean's "pulse." As teachers, we strive for interdisciplinary, even integrated, connections, and here at sea, this is best example that I have seen. 

Kathryn Ferguson and Brian Bill hard at work. 
Brian Bill, the research associate for NOAA-NWFSC, has been working diligently day and night with the team and on his own, using equipment foreign to me, analyzing the assemblage and health of the phytoplankton communities throughout our sampling sites. His focus has been on methods that reveal the taxonomy of organisms, classifying the autophototrophs (photosynthesizing organisms) and analyzing the production of domoic acid by harmful species. The question that he and NOAA-NWFSC is trying to answer is: Do the toxin levels in phytoplankton increase with lower pH (higher acidity levels) of the ocean? 

Brian has been working for NOAA since a biology undergrad at UW (pronounced "u-dub" by those that go there) in Seattle. From the area, Tacoma, Washington, Brian continued his work with NOAA as he began and completed his master's degree in marine biology at SFSU with Dr. Cochlan. After his master's degree, his title became oceanographer with NOAA, a fantastic career that few chose and fewer attain.

Kathryn Ferguson, Hollings Scholar, FSU/NOAA-NWFSC
Kathryn Ferguson, 21, has been assisting Brian. She's an intern for the summer with NOAA and will be staying in Seattle to work. Kathryn, or "Sunshine," as she's known on board for her contagious smile, is a prestigious Hollings scholar from Florida State University. Originally from Maryland, she now makes Orlando her home (in the "Sunshine State"). 

Brian and Kathryn have been physically counting the "general abundance" of phytoplankton and identifying the types that are present with each water sample. They use a technique that concentrates the phytoplankton through a sieve allowing them to see as many as possible in a small volume of water. The most common genera in their samples so far have been: Chaetoceros and Pseudo-nitzschia. Both of these can be harmful species of diatoms. The former sometimes kills fish; and the latter produces the poison, domoic acid

Remember that in the food web it's all connected. Phytoplankton produce their own food as autophototrophs, but they also produce lipids (think Omega-3) and toxins, such as domoic acid. These cannot be produced by any other source. As zooplankton, such as krill, eat the phytoplankton, they gain the nutrients as well as the lipids and toxins. Then the predators eat the zooplankton and all that is within them. So, just like the omega-3 lipids that are transferred to us when we eat fish, the domoic acid is transferred and accumulates in our bodies, causing sickness and even death. ASP, amnesic shellfish poisoning, is named because of the attack on the nervous system that causes temporary memory loss. It's a scary thought because the fish and shellfish are unaffected; it's us consumers that pay the price.

Dr. Vera Trainer, Brian Bill and Kathryn Ferguson are playing a huge role in the determination of toxic content in the communities that we are analyzing. Finding these two phytoplankton types, Chaetoceros and Pseudo-nitzschia, in the greatest abundance in our samples is not a good sign. 

After finding these two harmful organisms in abundance, Brian goes to work analyzing the amount of domoic acid present in their cells. He uses a tool to detect toxic activity called ELISA (Enzyme Linked Immune Assay). He creates a standard curve with an expensive plate and machine that measures the optical density or color of the reaction on the special plate. Because this is a competition reaction, the more color, the less domoic acid. These plates are showing a lighter blue which means that the amount of domoic acid is high. 

NOAA-Northwest Fisheries Science Center works hard daily to analyze the waters, to communicate with fisheries, and to create public awareness programs for toxins such as domoic acid as well as harmful algae blooms which both may be increased by the lowering pH of the ocean. But, we don't know that yet, which is why we are here.

These are the samples before the diluted hydrochloric
acid (HCl) is added to each.
Brian uses this special pipette to add 0.1mL to each sample.
After the HCl (diluted hydrochloric acid) is added,
the samples change colors (indication of chemical change).
The lighter blue or clearer indicates high amounts of
domoic acid. This one is off the charts.
The plate goes into machine that reads the optical density of each sample.

Analysis of the plate gives Brian the standard curve.

Making a plate for domoic acid analysis
Standard curve used to determine
production of domoic acid.
For quick analysis of the general
abundance, a phytoplankton net tow is
used to make collections.

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