Toxic microalgae on coral reefs and their seaweed hosts
I am investigating the effects of macroalgal (seaweed) biomass and species composition on the densities of toxic microalgae, focusing on several species of dinoflagellates that cause ciguatera poisoning in people. These dinoflagellates are found primarily in the tropics, and when they are consumed by fish that graze on the macroalgal hosts that they live on, the toxins that they produce are transferred to the fish. These toxins persist in the fish's tissue, and biomagnify as they are passed up the food chain. When people consume contaminated fish, they become sick with ciguatera poisoning. Ciguatera poisoning affects people around the world who live in tropical coastal areas, and is a particular issue in many Pacific island nations where I do my research.
My current work is being conducted in Moorea, French Polynesia (South Pacific), and is a follow-up to a study I conducted during an undergraduate field research program, Stanford@SEA (cruise S211). For that study, I worked with another student, Maija Leff, to survey the densities of ciguatoxic dinoflagellates at a several geographically similar atolls that differed in the size of the human populations that they supported. We found higher densities of ciguatoxic dinoflagellates at reefs with higher macroalgal abundance (which was generally associated with higher fishing pressure). This finding suggested that macroalgae-dominated reefs may provide better habitats for the dinoflagellates that cause ciguatera poisoning. I currently am studying how macroalgal species and biomass both influence the density of ciguatoxic dinoflagellates, to determine if reef-level densities of these dinoflagellates can be predicted in part by the amount and types of different macroalgal hosts that are present on a reef.
My current work is being conducted in Moorea, French Polynesia (South Pacific), and is a follow-up to a study I conducted during an undergraduate field research program, Stanford@SEA (cruise S211). For that study, I worked with another student, Maija Leff, to survey the densities of ciguatoxic dinoflagellates at a several geographically similar atolls that differed in the size of the human populations that they supported. We found higher densities of ciguatoxic dinoflagellates at reefs with higher macroalgal abundance (which was generally associated with higher fishing pressure). This finding suggested that macroalgae-dominated reefs may provide better habitats for the dinoflagellates that cause ciguatera poisoning. I currently am studying how macroalgal species and biomass both influence the density of ciguatoxic dinoflagellates, to determine if reef-level densities of these dinoflagellates can be predicted in part by the amount and types of different macroalgal hosts that are present on a reef.
© Amy A. Briggs, 2014