Arctic Ice Melt May Reduce Red Tides in the Gulf of Maine
Arctic melt water flowing into the Gulf of Maine could be the catalyst for a decrease in the toxic blooms of Alexandrium fundyense, the Gulf of Maine red tide. These toxins accumulate in shellfish and have caused widespread closures of shellfish harvesting to protect public health.
The main source of nutrients in the Gulf of Maine is deep water flows in from outside the Gulf. When the proportion of Arctic meltwater increases, the nutrient concentrations decrease and nutrient ratios change. As a result, benign diatoms bloom, leaving fewer nutrients for dinoflagellates like Alexandrium. In a recent news story, researchers funded by the National Centers for Coastal Ocean Science hypothesized that the much smaller than expected bloom this year may have been due to this altered nutrient regime.
Townsend, D.W., Rebuck, N.D., Thomas, M.A., Karp Boss, L, Gettings, R.M. 2010. A Changing Nutrient Regime in the Gulf of Maine. (PDF) Continental Shelf Research 30: 820-832.