Novel temperature gradient incubator to study the effects of temperature on motile aquatic organisms

Adam W. Heinze, Robert W. Sanders

Limnol. Oceanogr. Methods 7:216-221 (2009) | DOI: 10.4319/lom.2009.7.216

ABSTRACT: Water temperature influences planktonic communities via biological (e.g., metabolic) and abiotic means. Investigating direct temperature effects in nature is confounded by multiple factors that may covary with temperature at various depths, especially during periods of seasonal stratification. Dissolved oxygen, nutrient availability, water density, and irradiance all change with depth in thermally stratified systems. We have designed a temperature gradient incubator that creates a range of temperature within a continuous 1.65-m transparent column. This novel instrument allows investigation of how motile plankton are distributed across a controlled range of temperatures, which, in the configuration presented here, is a change of 8°C within the vertical column. The temperature gradient incubator allows elimination of confounding variables to test what portion of vertical migration within the water column is due strictly to changes in temperature. With simple reconfiguration of the light sources, interaction of temperature and irradiance effects on plankton can also be evaluated.