Multiyear data on benthic foraminifera in a glaciated fjord of Svalbard

Glaciers in the fjords of Svalbard have been receding over last decades. Tempelfjorden, a typical glaciated fjord in West Spitsbergen (78°24′06″ N, 17°02′30″ E), has been sampled in summer 1995 and 2001–2007 for modern benthic foraminifera. We have normalized the abundances and unified the taxonomy of all these published and unpublished data sets and then compiled the record of foraminiferal assemblages changing over years into a comprehensive database. The record includes data on living and dead abundances of benthic foraminiferal species in the surface sediments (0–2 cm) and downcore abundances of living foraminifera (only for 2004). This database portrays benthic foraminifera, this key group of microfossils, in a gradually changing Arctic environment

Toxisarcon taimyr sp. nov., a new large monothalamous foraminifer from the Kara Sea inner shelf

A large monothalamous foraminiferan, Toxisarcon taimyr sp. nov., has been isolated from the benthic samples from the Kara Sea inner shelf near the mouth of Yenisey river estuary, at a depth of 50–100 m. In its overall morphology, the new species closely resembles T. synsuicidica, one of the two species of Toxisarcon described to date. It possesses a large irregularly shaped cell body, covered by a thin layer of a fibrous organic coating. Numerous reticulopodia typically extend from all over the cell surface; the species is very motile and rapidly changes cell shape. Long and thick reticulopodial bundles form in the direction of movement. In the phylogenetic tree based on partial small-subunit ribosomal DNA (SSU rDNA) sequences, T. taimyr branches together with the two other known species of Toxisarcon within the clade C of monothalamous foraminifera

The Helgoland Experiment - assessing the influence of methodologies on Recent benthic foraminiferal assemblage composition

Most recent benthic foraminiferal studies focus on species inventory and distribution and ecology. An integration of results from different studies is often hampered by the application of different methods. The influence of different sample treatments and analyses on the accuracy of faunal data is the subject of the present study. We compare preservation, staining, and preparation techniques to constrain the internal data variability as inferred by different methodologies. Variations produced by different persons analysing the same foraminiferal assemblage and consequences for the accuracy of foraminiferal data are addressed. We retrieved a large surface sediment sample from the southeastern North Sea near Helgoland. Twelve replicate subsamples were taken and preserved with ethanol, ethanol - rose Bengal solution, or formaldehyde. Samples were then processed with standard methods. Some samples were stained after processing with an aqueous rose Bengal solution, or the foraminifera were concentrated by floatation. Coloration of specimens that were living at the time of sampling was different between samples where rose Bengal was added together with the ethanol and samples, which were stained after washing. In the latter case, only the last two or three chambers were impregnated. The sample preserved with formaldehyde showed dissolution features affecting both arenaceous and calcareous species. In particular, the outer shell layer of miliolids was corroded, calcareous cement of agglutinated tests was reduced, and pores of rotalids were enlarged. The population density reflecting the number of recognised, stained specimens was highly variable among different preservation, picking modes, and examinators. The accuracy of picking was in the range of ±4 % (1-sigma), while the reproducibility ranged from -44 to +26 % between different examinators, which also concerns the proportions of dominant species. There was no significant difference between wet and dry picking within the 95 % confidence limits, but samples that were stained later or concentrated by floatation generally yielded a lower number of specimens. Arenaceous species and miliolids were underrepresented in samples that were stained after washing and in the floatation concentrate while Stainforthia fusiformis was seemingly better recognised therein. More data and parallel investigations involving a larger number of specialists are needed to achieve a better comparability of faunal census data

Three new species of Gromia (Protista, Rhizaria) from western Greenland fjords

Species of large, testate, rhizarian protists in the genus Gromia are often common in high-latitude coastal environments, including fjords, but are frequently overlooked and almost all are undescribed. Here, we describe three new gromiid species from the Nuuk fjord system on the west coast of southern Greenland. Morphologically, the new species differ in the size and shape of the test. Gromia cucumiformis sp. nov. is elongate, up to 5.5 mm long, with a length:width (L/W) ratio of 4.3–5.5; Gromia botelliformis sp. nov. is up to 2.1 mm long, with a L/W ratio of 3.0–4.8; Gromia brevis is typically less than 1.0 mm long, with a L/W ratio around 2.0. Genetically, they are well-characterised and split between two clades. Gromia cucumiformis and G. brevis branch with several species of deep-water gromiids from the Arabian Sea and the Weddell Sea, while G. botelliformis branches with deep Weddell Sea species and several unnamed and morphologically uncharacterised gromiids from different parts of the world. Gromia botelliformis and G. brevis are currently known only from the Nuuk fjords, but sequences of G. cucumiformis from Greenland group together with sequences from Svalbard and the White Sea. Our genetic data reveal four additional clades of undescribed Gromia species. One contains sequences from Greenland, Svalbard and the White Sea, two comprises sequence from Greenland and the White Sea and one is limited to sequences from Greenland. These results demonstrate the high genetic diversity of gromiids and their widespread distribution in Arctic as well as in deep-sea environments

Intertidal foraminiferal fauna and the distribution of Elphidiidae at Chupa Inlet, western White Sea

The bright colouration of the cytoplasm in intertidal rotaliid foraminifera and their particle-gathering activity reliably reveals live specimens in fresh samples, without any fixatives or dyes applied. Using this approach, we demonstrate that live representatives of three rotaliid species, all belonging to the genus Elphidium, were common on intertidal mud and sand beaches. Two species, E. excavatum clavatum and E. albiumbilicatum, lived close to freshwater outflows, whereas E. williamsoni occupied beaches bathed by waters with normal salinity (surface 26–27‰ in the western White Sea). A least 13 species were found alive in the intertidal zone. Among non-calcareous foraminifera, Miliammina fusca, Ammotium cassis and Ovammina opaca were the most numerous

Foram-AMBI: A sensitivity index based on benthic foraminiferal faunas from North-East Atlantic and Arctic fjords, continental shelves and slopes

Highlights • Foraminiferal species were assigned to ecological groups according to AMBI procedure. • The benthic foraminifera-based Foram-AMBI was calculated using the AMBI formula. • Foram-AMBI was successfully tested on independent data sets. • Foram-AMBI correlates well with Shannon's diversity and TOC in test data sets. • Foram-AMBI reflects a stress gradient caused by increased organic carbon. The present study follows up the FOraminiferal BIo-MOnitoring (FOBIMO) working group's aim to explore methods which will improve the usefulness of benthic foraminifera in environmental monitoring. An internationally well-established marine biotic index, AMBI, commonly applied to assess ecological quality status was adapted for use on benthic foraminifera. As required by the AMBI formula, species were assigned to one of five ecological groups according to their sensitivity/tolerance to conditions along an increasing stress gradient (here increasing organic matter enrichment). For the assignments, we used 19 published data sets on fully marine NE Atlantic and Arctic fjord, continental shelf, and slope assemblages for which total organic carbon (TOC) data were available. Assignments were based on the relative abundance of the different species along associated TOC gradients. Of the 128 assigned species, the majority was assigned to Groups I–III dominating in low to moderately organic enriched environments with a high to good ecological quality status. Groups IV and V, representing strongly organically enriched environments with a moderate to poor ecological quality status, had 1 and 2 species, respectively. The resulting foraminifera-based Foram-AMBI was calculated using the AMBI formula and tested on four independent foraminiferal data sets from the same geographical region. The validation included correlations of the Foram-AMBI with Shannon's diversity (H′log2) as well as with the organic carbon content in the validation data sets. In two validation data sets from the Norwegian Skagerrak coast, a high proportion of the assemblages consisted of assigned species. The results showed a good correlation between the Foram-AMBI and both the TOC and Shannon's diversity H′log2. In two more southern validation data sets all TOC values were low and the abundance of unassigned species was too high for the Foram-AMBI to provide trustworthy results. The Foram-AMBI of the two validation data sets with high abundance of assigned species clearly reflected an increasing organic carbon-induced stress gradient. Hence, this first attempt to apply the AMBI formula on benthic foraminiferal data shows promising results. However, to improve the applicability of Foram-AMBI, there is a need to assign more species by obtaining data from studies along wide organic carbon pressure gradients, particularly from the southern North Sea and southwards

Sea surface reconstruction of sediment cores off West Spitsbergen

Two sediment cores from the West Spitsbergen area, Euro-Arctic margin, MD99-2304 and MD99-2305, have been investigated for paleoceanographic proxies, including benthic and planktonic foraminifera, benthic foraminiferal stable isotopes and ice rafted debris. Core MD99-2304 is located on the upper continental margin, reflecting variations in the influx of Atlantic Water in the West Spitsbergen Current. Core MD99-2305 is located in Van Mijenfjord, picturing variations in tidewater glacier activity as well as fjord-ocean circulation changes. Surface water warmer than today, was present on the margin as soon as the Van Mijenfjord was deglaciated by 11,200 cal. years BP. Relatively warm water invaded the fjord bottom almost immediately after the deglaciation. A relatively warm early Holocene was followed by an abrupt cooling at 8800 cal. years BP on the continental margin. Another cooling in the fjord record, 8000-4000 cal. years BP, is documented by an increase in ice rafted debris and an increase in benthic foraminiferal delta18O. The IRD-record indicates that central Spitsbergen never was completely deglaciated during the Holocene. Relatively cool and stable conditions similar to the present were established about 4000 cal. years BP

Marine Lake Mogilnoe (Kildin Island, the Barents Sea): one hundred years of solitude

Lake Mogilnoe (Kildin Island, the Barents Sea) is a marine stratified lake, a refuge for landlocked populations of marine organisms. Unlike other known marine lakes from polar areas, which communicate with the sea by water percolation at the surface, Mogilnoe has a subterranean connection with the sea like tropical and subtropical anchialine lakes. Similarly to some other marine lakes, Mogilnoe has traditionally been considered to be biologically isolated from the sea and subject to little change. We review the current status of the physical features, zooplankton and benthos of Mogilnoe and trace changes that have occurred in the lake since the start of observations in 1894. The anaerobic bottom water layer has expanded by 100 %, while the upper freshwater layer has diminished by 40 %. The species diversity of zooplankton and macrobenthos has halved. The occurrence of Atlantic cod likens Mogilnoe to some other Arctic marine lakes while the presence of large flocks of sea anemones, scyphomedusae and suberitid sponges makes it similar to tropical anchialine lakes. Lake Mogilnoe is not entirely biologically isolated; accidental introduction of species from the sea does occur. We argue that the idealised model of an isolated steady-state ecosystem can be applied to a marine lake with caution. A model of fluctuating abiotic environment and partial biological isolation portrays the real situation better