DV-13-06 Effects of Alexandrium saxitoxins on the life history of green sea urchin

Tyler Carrier
University of Maine

Tyler Carrier was listening to a podcast about harmful algal blooms on the West Coast, where researchers were finding sea urchins washing ashore. He wondered whether juvenile stages of urchins and other echinoderms might be affected by harmful algae, which have become more frequent and intense in the Gulf of Maine. During these annual “red tides” large numbers of the toxic dinoflagellate Alexandrium fundyense are present in the phytoplankton and accumulate in filter-feeding organisms such as clams and mussels. Other organisms at various life stages eat plankton, too, including the larvae of the green sea urchin (Strongylocentrotus droebachiensis), a commercially important species in Maine. But Carrier found little information about how Maine urchins, especially developing juveniles, are affected by toxic algae.

Carrier, an undergraduate student in the Honors College at the University of Maine, worked in laboratories with Lee Karp-Boss, David Townsend, Paul Rawson, and Mary Tyler. They exposed sea urchin larvae to different concentrations of saxitoxins and documented grazing and effects on morphological development. Green sea urchin larvae consumed Alexandrium at a variety of concentrations ecologically relevant to the Gulf of Maine, including when other food choices were present. Carrier found that urchins exposed to saxitoxins had drastically altered development, although the mechanisms were unclear. His results suggest that red tide is not just a problem for bivalve shellfish.

Sea Grant funds: $1,500