Scale dependent diversity of harpacticoid copepods in a shallow Antarctic bay

VEIT-KÖHLER G. Y J. ANTACLI

Curitiba, Brasil

Simposio; IX SCAR International Biology Symposium; 2005

Pontificia Universidade Catolica do Parana (PUC-PR)

This study presents data of an investigation on benthic harpacticoid copepods in Potter Cove, Antarctica (62°14´S, 58° 40´W), with especial emphasis on spatial distribution and relation to environmental factors. One depth transect (5, 10, 20 and 30 m) was sampled during the Antarctic summer (02/02/04-29/03/04). Meiofaunal samples were collected by scuba diving. At each depth twelve sediments corers of 80 cm2 each were randomly pushed into the sediment and brought to the surface. The upper 10 cm of oxidized sediment layer of the corers were split into four equal parts each to study vertical distribution of the meiofaunal components and vertical variation of sediment factors. Six of the total corers were used to meiofaunal identification (mainly harpacticoid copepods). The fixed samples were washed using a 40 um mesh size with tap water. The rest of the corers were used to analyze sediment factors (total organic matter, carbon: nitrogen ratio, chloroplastic equivalents and grain size of sediments). For this reason, these corers were frozen for posterior analysis. Grain size analysis was conducted with freeze-dried sediment samples for the inorganic sediment components. The total organic matter (TOM) represented by the ash-free dry weight of the freeze-dried and homogenized sediment was determined. Chloroplastic pigments were extracted from defrosted homogenized sediment samples. A binocular was used to taxonomical identification of copepods. The distribution of the two species Pseudotachidius jubanyensis and Scottopsyllus (S.) praecipuus was studied in detail. Statistical analyses indicate that the distribution of harpacticoid copepods was related more to total organic matter than the carbon:nitrogen ratio and chloroplastic equivalents or even grain size and depth. While P. jubanyensis was strongly connected to depth and to a lesser extent to small grain size, S. (S.) praecipuus showed a preference for sites with low chloroplastic equivalent values, but neither of them was related to total organic matter.