Demersal fishes from the antarctic shelf and deep sea: A diet study based on fatty acid patterns and gut content analyses
Wuerzberg, L. ; Peters, J. ; Florentino De Souza Silva, A.P. ; Brandt, A. - \ 2011
Deep-Sea Research. Part II, tropical studies in oceanography 58 (2011)19-20. - ISSN 0967-0645 - p. 2036 - 2042.
south shetland islands - eastern north pacific - terra-nova bay - feeding-habits - ross sea - trematomus-bernacchii - notothenioid fishes - calanus-propinquus - lipid compositions - calanoides-acutus
The gut contents and fatty acid composition of 49 fish belonging to five Antarctic demersal families (Nototheniidae, Macrouridae, Channichtyidae, Bathydraconidae and Artedidraconidae) sampled at two stations at the Southern Ocean shelf and deep sea (600 and 2150 m) were analysed in order to identify their main food resource by linking trophic biomarkers with the dietary items found in the fish guts. Main food items of most fish analysed were amphipod crustaceans (e.g. in 63% of Trematomus bernachii guts) and polychaetes (e.g. in 80% of Bathydraco sp. guts), but other food items including fish, other crustaceans and gastropods were also ingested. The most prominent fatty acids found were 20:5(n-3), 16:0, 22:6(n-3) and 18:1(n-9). The results of gut content and fatty acid analyses indicate that all fish except the Channichthyidae share similar food resources irrespective of their depth distribution, i.e. benthic amphipods and polychaetes. A difference of the dietary spectrum can be observed with ontogenetic phases rather than between species, as high values of typical calanoid copepod marker fatty acids as 22:1(n-11) indicate that younger (smaller) specimens include more zooplankton in their diet.
Biodiversity change after climate-induced ice-shelf collapse in the Antarctic
Gutt, J. ; Barratt, I. ; Domack, E. ; Scheidat, M. - \ 2011
Deep-Sea Research. Part II, tropical studies in oceanography 58 (2011)1-2. - ISSN 0967-0645 - p. 74 - 83.
western weddell sea - deep-sea - species-diversity - southern-ocean - 1st insights - ross sea - peninsula - impact - aggregations - biogeography
The marine ecosystem on the eastern shelf of the Antarctic Peninsula was surveyed 5 and 12 years after the climate-induced collapse of the Larsen A and B ice shelves. An impoverished benthic fauna was discovered, that included deep-sea species presumed to be remnants from ice-covered conditions. The current structure of various ecosystem components appears to result from extremely different response rates to the change from an oligotrophic sub-ice-shelf ecosystem to a productive shelf ecosystem. Meiobenthic communities remained impoverished only inside the embayments. On local scales, macro- and mega-epibenthic diversity was generally low, with pioneer species and typical Antarctic megabenthic shelf species interspersed. Antarctic Minke whales and seals utilised the Larsen A/B area to feed on presumably newly established krill and pelagic fish biomass. Ecosystem impacts also extended well beyond the zone of ice-shelf collapse, with areas of high benthic disturbance resulting from scour by icebergs discharged from the Larsen embayments