Living benthic foraminifera of the Okhotsk Sea: Faunal composition,standing stocks and microhabitats |
| |
| Institution: | 1. GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany;2. Goethe University Frankfurt, Institute of Geosciences, Altenhöferallee 1, 60438 Frankfurt am Main, Germany;3. Alfred-Wegner-Institute Helmholtz Centre for Polar and Marine Research, 27570 Bremerhaven, Germany;1. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China;2. Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, SOA, Qingdao 266061, PR China;3. Department of Genetics and Evolution, University of Geneva, Switzerland;4. National Institute of Oceanography, Dona Paula, Goa-403004, India;5. Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, PR China;6. University of Chinese Academy of Sciences, Beijing 100049, China;1. Norwegian Polar Institute, Fram Centre, N-9296 Tromsø, Norway;2. Department of Geosciences, UiT The Arctic University of Norway in Tromsø, N-9037 Tromsø, Norway;3. Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115, USA;4. Faculty of Earth Sciences, Vrije Universiteit, De Boelelaan 1085, 1081, HV, Amsterdam, Netherlands;5. Institute of Oceanology Polish Academy of Sciences, ul. Powstańców Warszawy 55, Sopot, Poland |
| |
| Abstract: | Live (Rose Bengal stained) benthic foraminifera were investigated in surface sediment samples from the Okhotsk Sea to reveal the relationship between faunal characteristics and environmental parameters. Live benthic foraminifera were quantified in the size fraction > 125 µm in the upper 8 cm of replicate sediment cores, recovered with a multicorer at five stations along the Sakhalin margin, and at three stations on the southwestern Kamchatka slope. The stations are from water depths between 625 to 1752 m, located close or within the present Okhotsk Sea oxygen minimum zone, with oxygen levels between 0.3 and 1.5 ml l- 1. At the high-productivity and ice-free Kamchatka stations, live benthic foraminifera are characterized by maximal standing stocks (about 1700-3700 individuals per 50 cm2), strong dominance of calcareous species (up to 87-91% of total live faunas), and maximal habitat depths (down to 5.2-6.7 cm depth). Vertical distributions of total faunal abundances exhibit a clear subsurface maximum in sediments. At the Sakhalin stations, which are seasonally ice-covered and less productive, live benthic foraminifera show lower standing stocks (about 200-1100 individuals per 50 cm2), lower abundance of calcareous species (10-64% of total live faunas), and shallower habitat depths (down to 2.5-5.4 cm depth). Faunal vertical distributions are characterized by maximum in the uppermost surface sediments. It is suggested that 1) lower and strongly seasonal organic matter flux, caused by the seasonal sea ice cover and seasonal upwelling, 2) lower bottom water oxygenation (0.3-1.1 ml l- 1), and 3) more pronounced influence of carbonate undersaturated bottom water along the Sakhalin margin are the main factors responsible for the observed faunal differences. According to species downcore distributions and average living depths, common calcareous species were identified as preferentially shallow, intermediate and deep infaunal. Foraminiferal microhabitat occupation correlates with the organic matter flux and the depth of the oxygenated layer in sediments. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
