High Arctic Ocean Research Articles

Diversity and Vertical Distribution of Microbial Eukaryotes in the Snow, Sea Ice and Seawater Near the North Pole at the End of the Polar Night

Our knowledge about the microorganisms living in the high Arctic Ocean is still rudimentary compared to other oceans mostly because of logistical challenges imposed by its inhospitable climate and the presence of a multi-year ice cap. We have used 18S rRNA gene libraries to study the diversity of microbial eukaryotes in the upper part of the water column (0–170 m depth), the sea ice (0–1.5 m depth) and the overlying snow from samples collected in the vicinity of the North Pole (N88°35′, E015°59) at the very end of the long polar night. We detected very diverse eukaryotes belonging to Alveolata, Fungi, Amoebozoa, Viridiplantae, Metazoa, Rhizaria, Heterokonta, and Telonemia. Different alveolates (dinoflagellates and Marine Alveolate Groups I and II species) were the most abundant and diverse in gene libraries from water and sea ice, representing 80% of the total number of clones and operational taxonomic units. Only contaminants and/or species from continental ecosystems were detected in snow, suggesting wind- and animal- or human-mediated cosmopolitan dispersal of some taxa. By contrast, sea ice and seawater samples harbored a larger and more similar inter-sample protist diversity as compared with snow. The North Pole was found to harbor distinctive eukaryotic communities along the vertical gradient with an unparalleled diversity of core dinoflagellates, largely dominant in libraries from the water column, as compared to other oceanic locations. In contrast, phototrophic organisms typical of Arctic sea ice and plankton, such as diatoms and prasinophytes, were very rare in our samples. This was most likely due to a decrease of their populations after several months of polar night darkness and to the presence of rich populations of diverse grazers. Whereas strict phototrophs were scarce, we identified a variety of likely mixotrophic taxa, which supports the idea that mixotrophy may be important for the survival of diverse protists through the long polar night.

Snow-depth observations by adventurers traveling on Arctic sea ice

AbstractSnow depth is a key parameter for assessing the sea-ice mass budget in the Arctic and for the surface energy balance at the atmosphere–snow–ice–ocean interfaces. However, scientific expeditions to the high Arctic Ocean are rare, and for large parts of the year no snow and ice data are collected in situ in most regions. Therefore any additional in situ observations of snow depth are of interest to the scientific community. Arctic adventurers and tourists are among the most frequent visitors to the Arctic Ocean and North Pole. If properly trained and carefully adhering to standard protocols, they could collect valuable snow-depth data from large regions. Here we analyse such data from four Arctic basin ski traverses carried out between 1994 and 2007. Individual datasets show characteristic regional differences of snow thickness, which provide invaluable information for the validation of models and satellite data. the observations were made applying a continuously upgraded observation guideline scheme. Earlier observations were based on a relatively broad view of easily observable snow and ice parameters. Improvements included requirements of more detailed snow-thickness surveys in order to observe the spatial variability over varying sea-ice surfaces in a better way. Possibilities for, and limitations of, ice-thickness estimates and measurements are also discussed. Often, assessment of ice thickness is more problematic since measurements are either time-consuming or biased, meaning that possibilities for collecting large datasets are limited.

Expanding the Cenozoic paleoceanographic record in the Central Arctic Ocean: IODP Expedition 302 Synthesis

Abstract The Arctic Coring Expedition (ACEX) proved to be one of the most transformational missions in almost 40 year of scientific ocean drilling. ACEX recovered the first Cenozoic sedimentary sequence from the Arctic Ocean and extended earlier piston core records from ≈1.5 Ma back to ≈56 Ma. The results have had a major impact in paleoceanography even though the recovered sediments represents only 29% of Cenozoic time. The missing time intervals were primarily the result of two unexpected hiatuses. This important Cenozoic paleoceanographic record was reconstructed from a total of 339 m sediments. The wide range of analyses conducted on the recovered material, along with studies that integrated regional tectonics and geophysical data, produced surprising results including high Arctic Ocean surface water temperatures and a hydrologically active climate during the Paleocene Eocene Thermal Maximum (PETM), the occurrence of a fresher water Arctic in the Eocene, ice-rafted debris as old as middle Eocene, a middle Eocene environment rife with organic carbon, and ventilation of the Arctic Ocean to the North Atlantic through the Fram Strait near the early-middle Miocene boundary. Taken together, these results have transformed our view of the Cenozoic Arctic Ocean and its role in the Earth climate system.

Introduction to special section on Cenozoic Paleoceanography of the Central Arctic Ocean

[1] In late summer 2004, the Integrated Ocean Drilling Program (IODP) conducted one of the most transformational missions in the almost 40 year history of scientific ocean drilling: the Arctic Coring Expedition (ACEX) [Backman et al., 2006; Moran et al., 2006a]. This technically challenging expedition [Moran et al., 2006b] to the Lomonosov Ridge near 88 N recovered the first long-term Cenozoic sediment record from the Arctic Ocean–extending previous records from 1.5 Ma to an unprecedented 56 Ma. Glimpses of the breadth of this transformation were seen during the ACEX cruise when the massulae from freshwater ferns (Azolla) were found in 49 Ma old sediments [Brinkhuis et al., 2006] and the presence of Apectodinium augustum confirmed that the Paleocene-Eocene thermal maximum (PETM) (55 Ma) was unexpectedly recovered [Sluijs et al., 2006]. [2] Soon after the expedition, when the cores were opened and analyzed, ice-rafted debris was found in surprisingly old (46 Ma) sediments [Moran et al., 2006a]. These middle Eocene sediments are characterized also by their high organic carbon content [Stein et al., 2006]. The exciting early results attracted other investigators that expanded the scientific investigating team to more than 40 people. Analyses were extended to include studies that revealed surprisingly high Arctic Ocean surface water temperatures [Sluijs et al., 2006] and an amplified hydrological system [Pagani et al., 2006] during the PETM. Initial analyses revealed an extensive hiatus encompassing about 26 million years that occurred below a short interval showing starkly alternating black and white layers that is now dubbed the ‘‘zebra’’ interval; thus the time interval from the late early Miocene (18 Ma) to the middle middle Eocene (44 Ma) is missing. Although the hiatus is a lost window in time for the Arctic paleoclimate record, it spawned other studies that integrated the regional tectonic history with ACEX results revealing a major oceanographic reorganization at 17.5 Ma–ventilation of the Arctic Ocean to the North Atlantic through the Fram Strait [Jakobsson et al., 2007]. In terms of ventilation and water mass history, Neogene neodymium isotope data reveal that Arctic Intermediate Waters originate from brine formation on Eurasian shelf areas between 15 and 2 Ma, and during glacial periods throughout Pleistocene times [Haley et al., 2008a]. They conclude that this mode of Arctic circulation differs markedly from today’s situation, showing relatively high contributions of North Atlantic Intermediate Water and minor input from brine formation. [3] In this special section, the transformation continues. Results from the large ACEX scientific ‘‘family’’ include: a robust age model; detailed analyses of the middle Eocene that document a unique brackish water environment; sea ice and iceberg history reconstructions as well as the provenance of ice-rafted debris from the Eocene to present; evolution of depositional environments; times of isolation and connection to the global ocean; geochemical analyses of the organic carbon-rich sediments; and unique applications of high-resolution proxies and cyclostratigraphy. Highlights from this special section are presented here.

Water mass transformation in the Greenland Sea during the 1990s

Time series of hydrographic and transient tracer measurements were used to study the variability of Greenland Sea water mass transformation between 1991 and 2000. Increases in tracer inventories indicate active renewal of Greenland Sea Intermediate Water (GSIW) at a rate of 0.1 to 0.2 Sv (1 Sv = 1 × 106 m3 s−1) (10‐year average). A temperature maximum (Tmax) was established at the base of the upper layer (500 m) as a consequence of anomalously strong freshwater input into the near‐surface layer at the beginning of the 1990s. Tmax rapidly descended to 1500 m by 1995 followed by a much slower rate of descent. GSIW became warmer and less saline compared to the 1980s. During the deepening phase of Tmax, atmospheric data revealed above‐average wind stress curl and oceanic heat loss. In addition, high Arctic Ocean sea‐ice export and lack of local sea‐ice formation have been documented for that period. A combination of all these factors may have evoked the renewal of GSIW with anomalously freshwater from the upper layers. The Tmax layer established a stability maximum that inhibits vertical exchange between intermediate and deeper waters. Temperature and salinity of deep waters continued to increase at rates of 0.01°C yr−1 and 0.001 yr−1, respectively. However, since 1993, decrease in and homogenization of deep water transient tracer concentrations indicate that renewal occurred predominantly by addition of Arctic Ocean waters. In 2000 the water column (500 m to 3400 m) required an additional 60 W m−2 (110 W m−2) over the annual mean heat loss to restore its heat content to 1989 (1971) values.

The phylogenetic position ofarcticomisop hria bathylaptevensisgen. et sp. n. (Crustacea: copepoda) a new misophrioid from hyperbenthic deep-sea waters in the laptev sea (arctic ocean)

Abstract Arcticomisophria bathylaptevensis gen. et sp. n., the first record of Misophrioida from the high Arctic Ocean is described. The new genus belongs to the Misophria-group. It has retained a number of plesiomorphic characters, especially in the antennule, maxillule, and the fifth swimming leg. These affect the reconstruction ofthe groundpattem of the Misophrioida and Podoplea. A key to the genera of the Misophria-group is provided.

Birds Observed in the Arctic Ocean to the North Pole

Bird sightings made in the high Arctic Ocean during a cruise to the North Pole from 18–24 July 1994 on board the Russian ice breaker Kapitan Dranitsyn are presented. Twenty-eight sightings of 6 spe...

Oceanographic-related variation in the bone sizes of extinct great auks

We measured the bones of extinct great auks Pinguinis impennis that were killed during recent centuries on Funk Island off the northeast coast of Newfoundland. Comparisons of these measurements with those taken elsewhere suggest that great auks from Funk Island, which is situated in a Low Arctic oceanographic region, were larger than conspecifics from Boreal oceanographic regions. This finding is supported by extant alcid species that inhabit Boreal, Low Arctic or Boreal through High Arctic ocean regions and tend to increase in body size with increasing latitude (generally decreasing sea surface temperature). We suggest that paleoecological sea surface temperatures and food webs may have favored oceanographic-related variation in body sizes of great auks. The variances of the bone sizes of great auks from Funk Island were not less than those of a sample of great auk bones collected from Scandinavian archaeological sites that cover an extensive geographic range and that span seven millenia. This finding is inconsistent with a previously suggested latitudinal cline in body size among great auks in Scandinavia. Research techniques and studies that could address questions of great auk feeding ecology and population genetics are considered.

Taxonomic Revision of the Marine Genus Phallodrilus Pierantoni (Oligochaeta, Tubificidae), with Descriptions of Thirteen New Species1

The taxonomy and morphology of Phallodrilus Pierantoni, 1902 are studied on the basis of material from various geographical areas. P. sabulosus sp.n., P. exiguus sp.n., P. tenuissimus sp.n., P. caudatus sp.n., P. planus sp.n. and P. extremus sp.n. are described from tropical and subtropical parts of the NW Atlantic, the four last‐mentioned species being void of alimentary canal. A polytypic species is established for the European P. rectisetosus rectisetosus subsp.n. and the NW Atlantic P. rectisetosus deminutius subsp.n. P. marionensis sp.n. and P. inconspicuus sp.n. are reported from the S Indian Ocean, P. firmus sp.n. from Iceland. Three deep‐sea species, P. remus sp.n., P. styloatriatus sp.n. (both N Atlantic), and P. simplidentatus sp.n. (from High Arctic Ocean) are described, and morphological notes and anew record are given for P. profundus Cook. Studies on types and other material enable morphological notes on P. minutus Hrabe', P. coeloprostatus Cook, P. obscurus Cook, P. parviatriatus Cook, P. prostatus (KnÖllner) and P. albidus Jamieson. The definition of the genus is modified, and the relation of Phallodrilus to other genera within the sub‐family Phallodrilinae is briefly discussed. Twenty‐three species of Phallodrilus are keyed out, principally on the basis of differences in the sexual organs of the different species.

Benthic ecology of the high arctic deep sea

An analysis is made of 75 quantitative benthic samples collected by Mini-LUBS, and 28 qualitative benthic samples collected with the “small biological trawl”, from Fletcher's Ice Island, T-3, while it was drifting over the Alpha Cordillera region of the High Arctic Ocean during October, 1969 through February, 1970 and in March, 1972. The depth range was 1000 to 2500 m. Benthic foraminiferans account for about 53%, bivalves for 27%, sponges for 7%, and polychaetes for 5% of the total biomass. Other groups make up the remaining 8%. The weight ratio of macro- to meiofauna is 1:1. Numerically, excluding Foraminifera, polychaetes comprise 42%, nematodes 16%, sponges 11%, and bivalves 8% of the total fauna. The remaining 23% is composed of 13 other taxa. Biomass in the Amerasian Basin at depths of 1000 to 2000 m is extremely low (0.04 g/m); it is comparable to depths of 5000 to 6000 m in the oligotrophic red-clay area of the mid-Pacific Ocean, and is 40 times less than biomass at comparable depths from Antarctica and off Peru. Diversity, as calculated by the Shannon-Weaver method, is low, suggesting that the Arctic ecosystem is young, as reported in earlier studies (Dunbar, 1968; Menzies et al., 1973). Although the H' values are low, no biocoenoses of oligomixity in the deep Arctic are revealed, contrary to previous statements and beliefs. There may be fewer major benthic groups in the Arctic Ocean than in other parts of the world oceans. Following the conventional terminology of Petersen (1913) and Thorson (1957), we have called the High Arctic biocoenoses of the Alpha Cordillera region a Thenea abyssorum-Spirorbis granulatus community.