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Objectives: Test the hypothesis that cryptophyte prey availability drives the formation of harmful algal blooms for mixotrophic algae such as Karlodinium veneficum (syn. K. micrum, Gymnodinium galatheanum, Gyrodinium setuariale). Methodology: In situ monitoring of cryptophytes will be accomplished by monitoring phycoerythrin fluorescence time series from established monitoring platforms (i.e. MD DNR @ Corsica and Rhode Rivers) and in spatial transects through existing blooms. Microscopy and flow cytometry will be used to supplement and validate fluorescence measurements. Statistical techniques will be applied to determine relationships between cryptophyes and HAB's in our newly collected data and in historical datasets such as the CBP phytoplankton count dataset. Rationale: Cryptophytes are ubiquitous in Chesapeake Bay (annual average: 20% of total Chl a), trend to thrive in the same eutrophic conditions associated with HAB's, yet little is known about cryptophyte population dynamics or their relationship with harmful algae that feed on them. Many harmful algae are mixotrophic and exhibit dramatic increases in growth rate (2-3 fold) when using cryptophytes as a food source for growth. This study will use in situ techniques to monitor temporal and spatial coupling between mixotrophic harmful algae and cryptophytes in Chesapeake Bay.
Place, AR; Bowers, HA; Bachvaroff, TR; Adolf, JE; Deeds, JR; Sheng, J. 2012. Karlodinium veneficum: the little dinoflagellate with a big bite. Harmful Algae14:179 -195. doi:10.1016/j.hal.2011.10.021. UM-SG-RS-2012-17.
Saba, GK; Steinberg, DK; Bronk, DA; Place, AR. 2011. The effects of harmful algal species and food concentration on zooplankton grazer production of dissolved organic matter and inorganic nutrients. Harmful Algae10(3):291 -303. doi:10.1016/j.hal.2010.11.003. UM-SG-RS-2011-16.
Adolf, JE; Bachvaroff, T; Place, AR. 2008. Can cryptophyte abundance trigger toxic Karlodinium veneficum blooms in eutrophic estuaries? Harmful Algae8(1):119 -128. doi:10.1016/j.hal.2008.08.003. UM-SG-RS-2008-01.
Hall, NS; Litaker, RW; Fensin, E; Adolf, JE; Bowers, HA; Place, AR; Paerl, HW. 2008. Environmental factors contributing to the development and demise of a toxic dinoflagellate (Karlodinium veneficum) bloom in a shallow, eutrophic, lagoonal estuary. Estuaries and Coasts31(2):402 -418. doi:10.1007/s12237-008-9035-x. UM-SG-RS-2008-24.