New data on sponges from Svalbard Archipelago with a description of a new species of Halicnemia

Sponge fauna from the west and south of Svalbard archipelago was studied. A total of 28 species of sponges were identified. Five of them are new records to the study area and one is new to science. New records for Spitsbergen are: Axinella hispida (Koltun 1959), Haliclona rossica (Hentschel 1929), Myxilla (Myxilla) perspinosa (Lundbeck 1905), Sphaerotylus borealis (Swartschewsky 1906) and Suberites carnosus (Johnston 1842). A new species of sponge, Halicnemia wagini sp. nov., collected south-west of Spitsbergen on the continental slope at a depth of 423–425 m, is described. It is similar to Halicnemia patera (Bowerbank 1864) and H. verticillata (Bowerbank 1866) in skeleton architecture, but significantly differs in its spicule complement and external appearance. Primarily, distinct differences concern the morphology of microscleres. In comparison with Halicnemia patera, the new species has an additional category of acanthose microscleres presented by microstrongyles, while microscleres of H. verticillata are only slightly curved and also verticillately spined. The study area, west of Spitsbergen, establishes close relationships with North Atlantic due to warm Atlantic waters of the West Spitsbergen Current. Proximity of the new species to the North Atlantic representatives of Halicnemia genus allowed us to suggest that H. wagini sp. nov., both ecologically and morphologically, has stood apart as a distinct biological species in the conditions of the Arctic.

http://www.zoobank.org/lsid:zoobank.org:pub:2A09537B-63D7-4F07-A2AB-9C707A686333     

Radiolarians from the British North‐Polar Expedition (1875–1876): re‐examination of the H. B. Brady (1878) collection

The earliest report on radiolarians from the Arctic Ocean (north of the Arctic Circle) was provided by H. B. Brady (1878 Brady, H. B. 1878. On the reticularian and radiolarian Rhizopoda (Foraminifera and Polycystina) of the North‐Polar Expedition of 1875–76.. Annals and Magazine of Natural History, Series 5, 1: 425–440. [Taylor & Francis Online] , [Google Scholar]). He documented the occurrences of 10 genera from soundings in northern Baffin Bay and north of Greenland, but he did not illustrate any specimens in his report. We have re‐examined Brady's original slide collection, housed at the Natural History Museum, London (NHM), in order to refine his radiolarian identifications to species level. We have identified 11 radiolarian taxa in his slides, but some are definitely more characteristic of tropical oceans rather than high northern latitudes. We conclude that this is most likely due to sample contamination or misidentification of samples. Therefore, the actual occurrence of tropically affiliated radiolarians recorded from the Arctic is uncertain and should be regarded with suspicion.     

Cladocera and Copepoda of Shokalsky Island: new data from northwest Siberia

Information on the freshwater fauna of the remote Arctic territories is very patchy, and most of the isolated islands of the Arctic Ocean remain absolutely unexplored. The pioneer data on the species composition of microcrustaceans of Shokalsky Island (northwest Siberia, Russia) is reported here. The initial three-year research revealed a total of 31 new for the area species of Cladocera and Copepoda, including new records for the whole of northwestern Siberia. Comparing the interannual differences in faunal composition, we suggested the hypothesis of the existence of a cryptic pool of species’ resting stages, which can invade the community in the event of favourable environmental conditions in the Arctic freshwaters. We also compiled all the available data from different parts of northern Siberia and compared them with the fauna of Shokalsky Island to analyse the connection between the diversity and distributional patterns of copepods and cladoceran species and the climate conditions of different territories.     

Microhabitat diversity of Svalbard Bryozoa

Bryozoans are one of the major macrofaunal groups of the high polar regions. Here we present data on the nature of bryozoan assemblages in the Svalbard Archipelago sampled over 6 years between 1997 and 2002. Samples were collected with use of Van Veen grab, dredge and Scuba diving at depths ranging from 0 to 268?m. Among examined material (5026 items) bryozoans were present on one type of abiotic (stones) and 40 types of biotic substrata. The biotic substrata we investigated included algae (12 taxa) and invertebrates (28 taxa: Hydrozoa, Gastropoda, Bivalvia, Polychaeta, Crustacea, Ascidiacea, other Bryozoa). Both a priori ANOSIM (Global R?=?0.512, P?=?0.001) and cluster analyses reveal differences between the assemblages on different types of substrata. Cluster analyses distinguish two distinct groups of substrata. The first (stable) included stones, molluscs and Balanus balanus whilst the second (flexible) consisted of algae, hydrozoans and bryozoans. Bryozoan assemblages which colonized different substrata, varied in terms of species composition and their dominance. Bryozoan species were categorized as generalists, low‐specificity epibiotic species or locally abundant background species. No species were found to be substratum‐specific to any type. Among substrata with the richest bryozoan fauna were stones (156 taxa), Chlamys islandica (68) and Balanus balanus (62). There were clear patterns in the distribution of substrata colonized by bryozoans within the fjord system: those shallow near the mouth were rich whilst those in deeper water were depauperate. We consider environmental gradients such as siltation and processes related to depth to be responsible for such patterns.     

Arctic species of the cheilostome bryozoan Microporella,with a redescription of the type species

This investigation focuses on the diversity and taxonomy of species of Microporella found north of the Arctic Circle. Firstly, however, a neotype is chosen for the Mediterranean type species M. ciliata (Pallas) in order to stabilize the taxonomy of this “pseudocosmopolitan” species, which has been recorded in the past from the Arctic. Study of type and other material using scanning electron microscopy shows that only two Arctic species of Microporella can be recognized, M. arctica Norman and M. klugei sp. nov. The first of these is characterized by a large ascopore divided by thin radial septa and situated close to the proximal rim of the orifice. Microporella klugei sp. nov. differs in having a smaller, undivided ascopore situated in a more proximal position on the frontal shield. Both Arctic species are notable among Microporella species for having a high proportion of autozooids without associated avicularia.     

On Liljeborgia fissicornis (M. Sars, 1858) and three related new species from Scandinavia,with a hypothesis on the origin of the group fissicornis

The large and common Scandinavian amphipod Liljeborgia fissicornis (M. Sars) is split into four species: the deep-water L. caliginis sp. nov. and L. charybdis sp. nov., and the shallow-water L. fissicornis and L. ossiani sp. nov. The poorly known species L. polosi Barnard and Karaman, recorded from the deep Canadian Basin of the Arctic Ocean, is considered as belonging to the same group. All those northern species are completely devoid of eyes, while similar species from the Antarctic and sub-Antarctic continental shelf do have eyes. It is hypothesized that the group fissicornis, which is specific to cold waters, derives from ancestors living on the continental shelf of the Southern Ocean. These ancestors would have adapted to deep-sea environments, losing their eyes completely. Then they would have migrated northwards through the cold abyss, and reached the cold but shallow waters of the Arctic/sub-Arctic continental shelf, without redeveloping visual organs.     

Propagation of planetary-scale zonal mean wind anomalies and polar oscillations

Global atmospheric variables can be physically decomposed into four components:(1) the zonal time averaged climate symmetric component,(2) the time averaged climate asymmetric,(3) the zonal-mean transient symmetric anomaly,and (4) the transient asymmetric anomaly.This study analyzes the relationships between the intra-seasonal and inter-annual variability of planetary scale decomposed zonal and meridional winds in the tropopause,and oscillations such as those from the El Ni o-Southern Oscillation (ENSO),the Arctic Oscillation (AO) and the Antarctic Oscillation (AAO).The tropical inter-annual zonal mean wind anomalies in the tropopause are linked with the ENSO cycle and can propagate into the subtropics,mid-latitudes,and polar front regions via abnormal meridional vertical cells.Similarly,tropical intra-seasonal (40-60-d) zonal wind anomalies can reach the subtropics and mid-latitudes.The polar intra-seasonal zonal wind anomalies in the tropopause can propagate toward high-latitude areas.Thus,the AO and the AAO are the result of the interaction and propagation of these planetary scale zonal wind anomalies.     

The leading correlation of the winter Aleutian Low with surface air temperature during the subsequent summer over the Arctic and its possible mechanism

The variations of surface air temperature(SAT)over the Arctic are closely related to global climate change.Based on reanalysis datasets and a newly defined Aleutian Low intensity index,we found a good correlation between intensity of winter Aleutian Low and the SAT over the Arctic during the subsequent summer.Explanations were given using correlation analysis,composite analysis,and singular value decomposition methods.When intensity of winter Aleutian Low was weaker,sea surface temperature appeared higher in the North Pacific in the subsequent spring and summer,resulting in mean meridional circulation anomalies and 500 hPa geopotential height anomalies in spring and summer.Anomalous upward motion in mid-latitudes and downward motion in high latitudes(Ferrel cell weakening)transported the warmer air to the north from lower layer to the upper layer followed by increases in the SAT over the Arctic.Anomalous downward motion over about 75°N also caused consequent adiabatic warming and contributed to inhibit the heat transportation from surface to upper layer.Negative 500 hPa geopotential height anomalies existed in mid-latitudes and positive anomalies existed in high latitudes.The pattern(low-in-south and high-in-north)benefited from increasing the inflow volume flux of the Bering Strait,which also made the SAT over the Arctic increase.The results of this study reveal the process that the summer SAT over the Arctic was modulated by interannual variability of intensity of winter Aleutian Low.     

北冰洋环境快速变化与生态响应*

随着全球变暖的加剧,北冰洋环境正在发生快速变化,水温升高、夏季海冰覆盖面积和海冰储量下降、淡水输入增加、盐度下降、海水酸化现象初现,导致原本依托海冰生存的北冰洋生态系统遭受前所未有的冲击。已有研究表明,与冰相关生物的生存状况正在恶化,初级生产者个体呈现小型化趋势,冰藻减少影响底栖生物产量,亚北极种入侵。由于北极环境和生态系统变化远超预期,而人类对生态系统、特别是北冰洋中心区的了解非常有限,如何尽快建立观测体系、加强对生态系统的了解、预测潜在的变化成为未来的重要课题。     

环北极国家北极研究布局及对中国的启示

 基于相关战略规划和研究计划等资料,分析了美国、俄罗斯、加拿大及北欧5国的北极相关研究布局,总结了各国北极战略的特点：美国凭借其雄厚的观测和研究实力,在未来北极的研究与开发中扮演重要角色;俄罗斯积极围绕领土和资源开展研究部署;加拿大重点关注极地资源的管理和利用;北欧5国寻求稳定和拓展各自北极利益。通过综合研判,提出了中国未来参与北极研究和合作的建议。