Weight of the Evidence is the Right Approach

• Published in: Ecological Applications
• Main Author: Jacobson, Joseph L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1995
• Subjects: Ecology; McMurdo Station; Winter Quarters Bay; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.2307/1942024; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F1942024; https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1942024

Sampling and field experiments were conducted from 1975 to 1990 to test how the structure of marine benthic communities around McMurdo Station, Antarctica varied with levels of anthropogenic contaminants in marine sediments. The structure of communities (e.g., infauna density, species composition, and life history characteristics) in contaminated and uncontaminated areas were compared with the structure of communities influenced by two large‐scale natural disturbances, anchor ice formation and uplift or iceberg scour. Benthic communities changed radically along a steep spatial gradient of anthropogenic hydrocarbon, metal, and PCB contamination around McMurdo Station. The heavily contaminated end of the gradient, Winter Quarters Bay, was low in infaunal and epifaunal abundance and was dominated by a few opportunistic species of polychaete worms, especially Capitella spp., Ophryotrocha claperedii, and Gyptis sp. These are relatively small and motile species. Closely related species live in organically enriched and anthropogenically disturbed sediments throughout temperate latitudes. The edge of the heavily contaminated bay, the transition area, contained several motile polychaete species with less opportunistic life histories, especially Tharyx sp. and Haploscoloplos kerguelensis. Uncontaminated sedimentary habitats harbored dense tube mats of infaunal animals numerically dominated by populations of polychaete worms, crustaceans, and a large suspension feeding bivalve. These species are generally large and relatively sessile, except for several crustacean species living among the tubes. Community patterns along the anthropogenic disturbance gradient were similar to community changes along a natural gradient of anchor ice disturbance. The same motile and opportunistic polychaete worms were most abundant where anchor ice freezing and uplift were most severe. The motile polychaetes, Tharyx sp., Haploscoloplos kerguelensis, and Polygordius sp., were abundant at the edge of the anchor ice disturbance zone. The ...