Changing ecology of Lake Victoria cichlids and their environment: evidence from C13 and N15 analyses

Eutrophication is an increasing global threat to freshwater ecosystems. East Africa’s Lake Victoria has suffered from severe eutrophication in the past decades which is partly responsible for the dramatic decline in haplochromine cichlid species diversity. However, some zooplanktivorous and detritivorous haplochromine species recovered and shifted their diet towards macro invertebrates and fish. We used four formalin preserved cichlid species caught over the past 35 years to investigate whether stable isotopes of these fish are reflecting the dietary changes, habitat differences and if these isotopes can be used as indicators of eutrophication. We found that d15N signatures mainly reflected dietary shifts to larger prey in all four haplochromine species. Shifts in d13C signatures likely represented habitat differences and dietary changes. In addition, a shift to remarkably heavy d13C signatures in 2011 was found for all four species which might infer increased primary production and thus eutrophication although more research is needed to confirm this hypothesis. The observed temporal changes confirm previous findings that preserved specimens can be used to trace historical changes in fish ecology and the aquatic environment. This highlights the need for continued sampling as this information could be of essence for reconstructing and predicting the effects of environmental changes.

Ether lipids in deep sea and swamp sediments

Methanogen ether lipids have been quantified in sediments from a Florida swamp and the Atlantic ocean. Swamp cores containing acyclic and monocyclic isopranyl ethers are clearly differentiated from deep sea sediments which also contain bicyclic compounds. A concentration maximum near the bottom of the sulfate reducing zone in deep sea sediments may reflect a biogeochemical system in which methanogenesis and sulfate reduction are coupled by the process of methane oxidation. Lipid diagenesis is evident in the deep sea sediments. Species zonation, possibly caused by oxygen sensitivity, is detected in the relative lipid abundances in swamp sediments.

An annotated bibliography of CERC coastal ecology research /

Includes indexes.

An annotated bibliography of CERC coastal ecology research /

Includes indexes.

An annotated bibliography on the uses of statistics in ecology; a search of 31 periodicals.

Mode of access: Internet.

Contributions to the genetics, taxonomy, and ecology of the Drosophila pseudoobscura and its relatives /

Title on spine: Drosophila pseudoobdscura and its relatives.

Advancing human ecology through progress in safety research.

Mode of access: Internet.

Report of the Committee on a Treatise on Marine Ecology and Paleoecology, 1946-1947 /

"Presented in preliminary form as Appendix H at the Annual Meeting of the Division, May 2, 1947."

Effects of engineering activities on the ecology of Pismo clams /

Mode of access: Internet.