PANGAEA - Publishing Network for Geoscientific & Environmental Data
The information system PANGAEA is operated as an Open Access library aimed at archiving, publishing and distributing georeferenced data from earth system research. The system guarantees long-term availability of its content through a commitment of the operating institutions.
Active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia - Römer, Miriam; Torres, Marta E; Kasten, Sabine; Kuhn, Gerhard; Graham, Alastair GC; Mau, Susan; Little, Crispin T S; Linse, Katrin; Pape, Thomas; Geprägs, Patrizia; Fischer, David; Wintersteller, Paul; Marcon, Yann; Rethemeyer, Janet; Bohrmann, Gerhard; shipboard scientific party ANT-XXIX/4
An extensive submarine cold-seep area was discovered on the northern shelf of South Georgia during R/V Polarstern cruise ANT-XXIX/4 in spring 2013. Hydroacoustic surveys documented the presence of 133 gas bubble emissions, which were restricted to glacially-formed fjords and troughs. Video-based sea floor observations confirmed the sea floor origin of the gas emissions and spatially related microbial mats. Effective methane transport from these emissions into the hydrosphere was proven by relative enrichments of dissolved methane in near-bottom waters. Stable carbon isotopic signatures pointed to a predominant microbial methane formation, presumably based on high organic matter sedimentation in this region. Although...
Response of three krill species to hypoxia and warming: An experimental approach to oxygen minimum zones expansion in coastal ecosystems - Tremblay, Nelly; Abele, Doris
To understand the adaptation of euphausiid (krill) species to oxygen minimum zones (OMZ), respiratory response and stress experiments combining hypoxia/reoxygenation exposure with warming were conducted. Experimental krill species were obtained from the Antarctic (South Georgia area), the Humboldt Current system (HCS, Chilean coast), and the Northern California Current system (NCCS, Oregon). Euphausia mucronata from the HCS shows oxyconforming or oxygen partial pressure (pO2)-dependent respiration below 80% air saturation (18 kPa). Normoxic subsurface oxygenation in winter posed a "high oxygen stress" for this species. The NCCS krill, Euphausia pacifica, and the Antarctic krill, Euphausia superba maintain respiration rates constant down to...
Phytoplankton composition and biomass during leg 7 of Galathea 3 cruise across the southern Indian Ocean - Schlüter, Louise; Henriksen, Peter; Nielsen, Torkel Gissel; Jakobsen, Hans Henrik
Phytoplankton composition and biomass was investigated across the southern Indian Ocean. Phytoplankton composition was determined from pigment analysis with subsequent calculations of group contributions to total chlorophyll a (Chl a) using CHEMTAX and, in addition, by examination in the microscope. The different plankton communities detected reflected the different water masses along a transect from Cape Town, South Africa, to Broome, Australia. The first station was influenced by the Agulhas Current with a very deep mixed surface layer. Based on pigment analysis this station was dominated by haptophytes, pelagophytes, cyanobacteria, and prasinophytes. Sub-Antarctic waters of the Southern Ocean were encountered at...
Planktonic foraminifera and their stable isotope record of MICNESS samples off Cape Cod - Keigwin, Lloyd D; Bice, David M; Copley, Nancy
Monthly samples of stratified plankton tows taken from the slope waters off Cape Cod nearly 25 years ago are used to describe the seasonal succession of planktonic foraminifera and their oxygen isotope ratios. The 15°C seasonal cycle of sea surface temperature (SST) accounts for a diverse mixture of tropical to subpolar species. Summer samples include various Globigerinoides and Neogloboquadrina dutertrei, whereas winter and early spring species include Globigerina bulloides and Neogloboquadrina pachyderma (dextral). Globorotalia inflata lives all year but at varying water depths. Compared with the fauna in 1960-1961 (described by R. Cifelli), our samples seem warmer. Because sea surface...