Heating up a cold subject: prospects for under-ice plankton research in lakes

Abstract

Long-term patterns and drivers of ecosystem structure may be misunderstood if knowledge of an ecosystem is derivedprimarily from a single season, a situation common in many temperate lakes where the role of winter has been lessstudied. In lakes, avoidance of winter research has been especially pronounced for those that experience winter ice,but critical ecological processes can take place under ice. Even when obscured bysnow, ice transmitting as little as 2%incident light can allow relatively high rates of photosynthesis, and winter trophic interactions may have year-roundrepercussions. Here, we offer a suite of research questions that require attention, in order to build a mature under-standing of seasonal plankton dynamics in lakes. Specifically, we ask freshwater ecologists to consider the extent towhich abundance and nutrition of winter primary productivity supports consumers under the ice, reorganizes foodwebs,and how long the effects of winter trophic dynamics extend throughout theyear. In addition, we recognize somecritical gaps in knowledge about physical and biogeochemical conditions at the time of ice-off. Worldwide shorteningin ice duration lends imperative to under-ice studies, in order to more fully understand changes in ecosystem structureand function that mayalready be underway.KEYWORDS: winter; ice; plankton; trophic interactions; nutritional quality; state transitions