Toward the development of a new toxicity test with the Arctic alga Nitzschia frigida.

There are limited data available related to the sensitivity of Arctic species to environmental contaminants, and this knowledge gap creates uncertainty in environmental risk assessments (ERAs). To help address this concern, we optimized culturing conditions to allow for toxicity tests with an Arctic diatom, Nitzschia frigida. We found optimal conditions for growth were Harrison's medium with natural seawater at 2 °C under a continuous photoperiod of 90 μmol photons m2 s-1. We then compared the response of N. frigida with the temperate standard diatom species Skeletonema costatum. We performed concurrent and repeated exposures of the two species to three compounds (zinc, copper, and 1-methylnaphthalene). EC50 values calculated from N. frigida exposures were consistently lower than those from S. costatum tests for metals, but not 1-methylnaphthalene. Overall, we have taken the inaugural steps toward the development of a new toxicity test method using an Arctic species to inform ERAs in northern regions.