Monday, April 26, 2010
Tuesday, April 20, 2010
Thursday, April 15, 2010
Shackell, N., Frank, K., Fisher, J., Petrie, B., & Leggett, W. (2009). Decline in top predator body size and changing climate alter trophic structure in an oceanic ecosystem Proceedings of the Royal Society B: Biological Sciences, 277 (1686), 1353-1360 DOI: 10.1098/rspb.2009.1020
Tuesday, April 13, 2010
Chapman, B., Morrell, L., Tosh, C., & Krause, J. (2010). Behavioural consequences of sensory plasticity in guppies Proceedings of the Royal Society B: Biological Sciences, 277 (1686), 1395-1401 DOI: 10.1098/rspb.2009.2055
Sunday, April 11, 2010
This study really excites me as it shows how functional morphology and swimming mode can be reflected in the ecology and evolution of animals. The authors in this study used digital particle image velocimetry (DPIV) to measure the wakes produced by swimming jellyfish. DPIV is a technique where you place neutrally buoyant beads into the water that fluoresce under light. You then shine a plane of light through the water and measure the movement of those beads, which is typically caused by some biological organism such as a moving or feeding animal. For example here is a DPIV of fish suction feeding with shrimp as prey.
Thursday, April 8, 2010
Tuesday, April 6, 2010
Most studies on turbidity investigate freshwater ecosystems and few studies have focused on the impacts of turbidity on marine ecosystems. Eianne et al. (1999) showed that invertebrate planktivores (jellyfish) replaced planktivorous fish within Norwegian turbid fiords. This was likely to be because increased turbidity levels reduced the possibility of foraging in visually oriented fish, while tactile feeding in jellyfish allowed them to continue to feed under light-limited conditions. A reduction in fish populations was unlikely to be a result of a reduction in plankton abundance. In fiords where fish populations were reduced zooplankton were more numerous and grew to larger sizes. This confirms modeling and experimental studies which show that turbidity is likely to have a top down effect within marine ecosystems by reducing the ability of fish to feed visually and this in turn leads to changes in prey composition.
Eiane, K., Aksnes, D.L., Bagoien, E., & Kaartvedt, S. (1999). Fish or jellies - a question of visibility? Limnology and Oceangraphy, 44 (5), 1352-1357