(Table 1) List of samples with carbonate mineralogy, stable isotope, and accessory-mineral information

Petrographic and stable-isotope (d13C, d18O) patterns of carbonates from the Logatchev Hydrothermal Field (LHF), the Gakkel Ridge (GR), and a Late Devonian outcrop from the Frankenwald (Germany) were compared in an attempt to understand the genesis of carbonate minerals in marine volcanic rocks. Specifically, were the carbonate samples from modern sea floor settings and the Devonian analog of hydrothermal origin, low-temperature abiogenic origin (as inferred for aragonite in serpentinites from elsewhere on the Mid-Atlantic Ridge), or biogenic origin? Aragonite is the most abundant carbonate mineral in serpentinites from the two modern spreading ridges and occurs within massive sulfides of the LHF. The precipitation and preservation of aragonite suggests high Mg2+ and sulfate concentrations in fluids. Values of d18OPDB as high as +5.3 per mill for serpentinite-hosted aragonite and as high as +4.2 per mill for sulfide-hosted aragonite are consistent with precipitation from cold seawater. Most of the corresponding d13C values indicate a marine carbon source, whereas d13C values for sulfide-hosted aragonite as high as +3.6 per mill may reflect residual carbon dioxide in the zone of methanogenesis. Calcite veins from the LHF, by contrast, have low d18OPDB (-20.0 per mill to -16.1 per mill) and d13C values (-5.8 per mill to -4.5 per mill), indicative of precipitation from hydrothermal solutions (~129°-186°C) dominated by magmatic CO2. Calcite formation was probably favored by fluid rock interactions at elevated temperatures, which tend to remove solutes that inhibit calcite precipitation in seawater (Mg2+ and sulfate). Devonian Frankenwald calcites show low d18O values, reflecting diagenetic and metamorphic overprinting. Values of d13C around 0 per mill for basalt-hosted calcite indicate seawater-derived inorganic carbon, whereas d13C values for serpentinite-hosted calcite agree with mantle-derived CO2 (for values as low as -6 per mill) with a contribution of amagmatic carbon (for values as low as -8.6 per mill), presumably methane. Secondary mineral phases from the LHF for which a biogenic origin appears feasible include dolomite dumbbells, clotted carbonate, and a network of iron- and silica-rich filaments.

Total V9 rDNA information organized at the metabarcode level (Database W4)

The present data set provides a tab separated text file compressed in a zip archive. The file includes metadata for each TaraOceans V9 rDNA metabarcode including the following fields: md5sum = unique identifier; lineage = taxonomic path associated to the metabarcode; pid = % identity to the closest reference barcode from V9_PR2; sequence = nucleotide sequence of the metabarcode; refs = identity of the best hit reference sequence(s); TARA_xxx = number of occurrences of this barcode in each of the 334 samples; totab = total abundance of the barcode ; cid = identifier of the OTU to which the barcode belongs; and taxogroup = high-taxonomic level assignation of this barcode. The file also includes three categories of functional annotations: (1) Chloroplast: yes, presence of permanent chloroplast; no, absence of permanent chloroplast ; NA, undetermined. (2) Symbiont (small partner): parasite, the species is a parasite; commensal, the species is a commensal; mutualist, the species is a mutualist symbiont, most often a microalgal taxon involved in photosymbiosis; no the species is not involved in a symbiosis as small partner; NA, undetermined. (3) Symbiont (host): photo, the host species relies on a mutualistic microalgal photosymbiont to survive (obligatory photosymbiosis); photo_falc, same as photo, but facultative relationship; photo_klep, the host species maintains chloroplasts from microalgal prey(s) to survive; photo_klep_falc, same as photo_klep, but facultative; Nfix, the host species must interact with a mutualistic symbiont providing N2 fixation to survive; Nfix_falc, same as Nfix, but facultative; no, the species is not involved in any mutualistic symbioses; NA, undetermined. For example, the collodarian/Brandtodinium symbiosis is annotated: Chloroplast, "no"; Symbiont (small), "no"; Symbiont (host), "photo", for the collodarian host; and: Chloroplast, "yes"; Symbiont (small), "mutualist"; Symbiont (host), "no", for the dinoflagellate microalgal endosymbiont.chloroplast = "yes", "no" or "NA"; symbiont.small = "parasite", "commensal", "mutualist", "no" or "NA"; symbiont.host = "photo", "photo_falc", "photo_klep", "Nfix", no or NA; benef = "Nfix", "no" or "NA"; trophism = Metazoa , heterotroph , NA , photosymbiosis , phototroph according to the previous fields.

Spatial distribution patterns of ascidians (Ascidiacea: Tunicata) in combination with information on bathymetry, oceanography, chlorophyll-a, and sea-ice on the continental shelves off the northern Antarctic Peninsula during POLARSTERN cruise ANT-XXIX/3

Ascidians (Ascidiacea: Tunicata) are sessile suspension feeders that represent dominant epifaunal components of the Southern Ocean shelf benthos and play a significant role in the pelagic-benthic coupling. Here, we report the results of a first study on the relationship between the distribution patterns of eight common and/or abundant (putative) ascidian species, and environmental drivers in the waters off the northern Antarctic Peninsula. During RV Polarstern cruise XXIX/3 (PS81) in January-March 2013, we used seabed imaging surveys along 28 photographic transects of 2 km length each at water depths from 70 to 770 m in three regions (northwestern Weddell Sea, southern Bransfield Strait and southern Drake Passage), differing in their general environmental setting, primarily oceanographic characteristics and sea-ice dynamics, to comparatively analyze the spatial patterns in the abundance of the selected ascidians, reliably to be identified in the photographs, at three nested spatial scales. At a regional (100-km) scale, the ascidian assemblages of the Weddell Sea differed significantly from those of the other two regions, whereas at an intermediate 10-km scale no such differences were detected among habitat types (bank, upper slope, slope, deep/canyon) on the shelf and at the shelf break within each region. These spatial patterns were superimposed by a marked small-scale (10-m) patchiness of ascidian distribution within the 2-km-long transects. Among the environmental variables considered in our study, a combination of water-mass characteristics, sea-ice dynamics (approximated by 5-year averages in sea-ice cover in the region of or surrounding the photographic stations), as well as the seabed ruggedness, was identified as explaining best the distribution patterns of the ascidians.

Sample information and classification of lower Miocene gravity-flow types of sediment core CRP-1 (Table 1)

Nineteen samples of the Cape Roberts-1 drillcore were taken from Miocene- age deposits, from 90.25 - 146.50 metres below seafloor (mbsf) for thin section and laser grain-size analysis. Using the grain-size distribution, detailed core logging, X-radiography and thin-section analysis of microstructures, coupled with a statistical grouping of the grain-size data, three main styles of gravity-flow sedimentation were revealed. Thin (centimetre-scale) muddy debris-flow deposits are the most common and are possibly tirggered by debris rain-out from sea-ice These deposits are characterised by very poorly sorted, faintly laminated muddy sandstones with coarse granules toward their base. Contacts are gradational to sharp. Variations on this style of mass-wasting deposit are rhythmically stacked sequences of pebbly-coarse sandstones representing successive thin debris-flow events. These suggest very high sedimentation rates on an unstable slope in a shallow-water proximal glacimarine environment. Sandy-silty turbidites appear more common in the lower sections of the core, below approximately 141.00 mbsf, although they occur occasionally with the debris flow deposits The turbidites are characterised by inversely to normally graded, well-laminated siltstones with occasional lonestones, and represent a more distal shallow-water glacimarine environment.