Feeling the heat: the feeding behavior and growth of Nucella ostrina in response to temperature
Lauren
A.
Yamane, University of South Carolina, lauren.yamane@msci.sc.edu
(Presenting)
Sarah
E.
Gilman, The Claremont Colleges, sgilman@jsd.claremont.edu
Brian
Helmuth, University of South Carolina, helmuth@biol.sc.edu
Forecasting the impacts of climate change on the geographic distribution of marine populations requires not only defining the temperatures that animals are experiencing in the field, but also determining the physiological and ecological responses of organisms to those temperatures. The rocky intertidal zone is a physiologically harsh environment where organisms are known to experience highly variable body temperatures, even over the course of one tidal cycle. During the summer at Puget Sound, the predatory intertidal gastropod Nucella ostrina (a dogwhelk) may reach a body temperature 20°C higher during emersion (low tide) than that attained during submersion (high tide). Additionally, because water has much greater thermal stability than air, snails experience a very narrow range of body temperatures during submersion whereas body temperature may fluctuate by 20°C during emersion. These temperatures are known to elicit specific subcellular responses, but how are responses manifested at the scale of the organism and the ecosystem at large? To determine the answers to these questions, we investigated the physiological and ecological responses of the carnivorous gastropod Nucella ostrina to three emersion temperatures (~12°C, ~20°C, ~28°C) and two submersion temperatures (~11°C and ~13.5°C) over 20 days at the Friday Harbor Laboratories. Snails were placed in one of 24 tanks. All tanks received continuously circulating seawater on a simulated tidal cycle. Heat lamps positioned at different heights above the animals generated emersion body temperatures, and submersion temperatures were controlled with water heaters. Measurements were made of N. ostrina growth and of the consumed prey, Balanus glandula. Dogwhelks at 12° and 20°C were found to gain significantly more new shell and overall mass than 28°C snails. Additionally, dogwhelks exposed to the highest emersion temperature (28°C) almost completely stopped feeding. Submersion temperatures had an opposite impact on N. ostrina, with the warmer treatment coupled to increasing growth and predation rates. Future studies may examine the mechanisms underlying these different responses to increase our understanding of and ability to predict the effects of climate change on intertidal organisms.
NASA Carbon Cycle & Ecosystems Active Awards Represented by this Poster: