My PhD research involves phytoplankton ecology, specifically how variations in key resources impact community structure.  Applying theories about competition and resource utilization to phytoplankton in the North Sea can help us answer important questions about the future of valuable fisheries within this region.  Changing nutrient availability due to de-eutrophication efforts have led to questions about potential shifts in the phytoplankton community. If a dramatic changes in phytoplankton community or nutritional value occur due to resource limitations, then this could also impact the energy transfer within the North Sea. Questions about the quality of food up the food change arise as well as will certain limitations lead to a dominance or a microbial or viral loop in phytoplankton energy cycles?  To study these questions, several Dutch marine research institutes, including the AMB group at IBED, developed the CHARLET projet (CHAnges in Resource Limitation and Energy Transfer).

To study how shifts in resources, especially in the relative ratio of one key resource to another, can affect community structure we use several different approaches:

1) Nutrient enrichment experiments at sea

2) Chemostat experiments using North Sea inoculum with differing Nitrogen:Phosphorus ratios and loads.

3) Chemostat experiments using North Sea inoculum with differing initial communities (nearshore vs outershore inoculum)

4) Correlations between phytoplankton present during research cruises and PN:PP/ambient nutrient sources.

One of the main reasons there is a concern about eutrophication, and therefore there have been efforts to reduce nutrient inputs into our coastal waters, is the link between this and harmful algal blooms.  In 2012, Ouwerkerkse Kreek in Zeeland experienced an unusually dense bloom of the toxicAlexandrium ostenfeldii.  A team with AMB assisted water managers in treating the bloom with hydrogen peroxide before it could contaminate shelfisheries in the area.  This successful treatment, previous used in a few lakes (see IBED-AMB's Dr. Hans Matthijs),  is the first use for the termination of a marine harmful algal bloom. 

RV Pelagia

Nutrient Enrichment Experiments at Sea prepartation

Chemostats of differing inoculums

• Masters Thesis: The role of nitrogenous nutrients in the occurrence of the harmful dinoflagellate blooms caused by Cochlodinium polykrikoides in Long Island estuaries (NY, USA)

My previous research also focused on phytoplankton, but more specifically, harmful species.  For my masters, conducted at the School of Marine and Atmospheric Sciences, at Stony Brook University, in New York, I studied the nutritional ecology of the red tide forming species Cochlodinium polykrikoides.  We found that organic nitrogen sources, in an DIN limited environment, allow C. polykrikoides to form vast, monospecific blooms in Long Island's estuaries.  

After my masters, I did a short internship during which we isolated an Irish strain of the newly identified Azadinium spinosum.  A species only recently linked with a relatively new shellfish toxin called azaspiracid.  We performed feeding experiments using blue mussels and A. spinosum to create a sort of "toxin budget" in hopes of a better understanding of how the phytoplankton and shellfish toxin content interplay.

Previous publications:

Masters work 

• Gobler C.J., Burson, A., Koch, F., Tang, Y., Mulholland, M.R., 2012. The role of nitrogenous nutrients in the occurrence of harmful algal blooms caused by Cochlodinium polykrikoides in New York estuaries (USA). Harmful Algae 17: 64-74
•  Gobler, C.J., Berry, D.L., Anderson, O.R.,  Burson, A., Koch, F., Rodgers, B.S., Moore L.K., Goleski J.A., Allam, B., Bowser, P., Tang, Y., Nuzzi, R. 2008. Characterization, dynamics, and ecological impacts of harmful Cochlodinium polykrikoides blooms on eastern Long Island, NY, USA. Harmful Algae 7: 293–307
• Koch, F., Burson, A., Tang, Y.Z., Collier, J.L., Fisher, N.S., Sanudo-Wilhelmy, S., Gobler, C.J.  Effects of harmful Cochlodinium polykrikoides (Dinophyceae) blooms on plankton communities and the cycling of nitrogen, carbon, and B-vitamins.  Submitted, MEPS

Other HAB research

• Salas, R., Tillmann, U., John, U., Kilcoyne, J., Burson, A., Cantwell, C., Hess, P., Jauffrais, T., & Silke, J. 2011. The role of Azadinium spinosum (Dinophyceae) in the production of azaspiracid shellfish poisoning in mussels. Harmful Algae, 10(6), 774-783.
• Gobler, C.J., Berry, D.L., Dyhrman, S.T., Wilhelm, S.W., Salamov, A., Lobanov, A.V., Zhang, Y., Collier, J.L., Wurch, L.L., Kustka, A.B., Dill, B.D., Shah, M., VerBerkmoes, N.C., Kuo, A., Terry, A., Pangilinan, J., Lindguist, E.A., Lucas, S., Paulsen, I.T., Hattenrath-Lehmann, T.K., Talmage, S.C., Walker, E.A., Koch, F., Burson, A.M., Marcoval, M.A., Tang, Y.Z., Lecleir, G.R., Coyne, K.J., Berg, G.M., Bertrand, E.M., Saito, M.A., Gladyshev, V.N., Grigoriev, I.V. 2011. Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics. Proceedings of the National Academy of Sciences 108(11): 4352-4357.

Cochlodinium polykrikoides bloom, Meetinghouse Creek, NY

Cochlodinium polykrikoides from Shinecock Bay, NY

Azadinium spinosum culture isolated from Killary Harbour, Ireland

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