Fibers spreading worldwide: Microplastics and other anthropogenic litter in an Arctic freshwater lake

Since the end of the 19th century, the circumpolar fauna of freshwater Mollusca has not been reviewed despite the substantial increase of knowledge on this subject. A review of the freshwater mollusks of the Arctic based on an analysis of published data, own results and examination of museum collections is presented. 104 species of Mollusca have been registered, which constitutes less than 2% of the global diversity. The actual diversity of the Circumpolar freshwater molluscs may lie between 100 and 120 species. No endemic taxa are found in the Arctic. The most species-rich Arctic subregion is Siberia, whereas the North America maintains the poorest fauna. The aquatic malacofauna of Beringia is similar to that of North America, and Beringia as a biogeographic region constitutes a part of the Nearctic. The ways of formation of the Circumpolar malacofauna are discussed, with evaluation of dispersal, adaptation, and environmental filtering as the faunogenesis factors. The number of non-alien species in the Circumpolar freshwater malacofauna remains very low, and only one reliable occurrence of an alien species is known. Among the Arctic molluscs only three have a conservation status other than ‘least concern’ or ‘data deficient’, whereas most resident species are widespread and abundant.

Freshwater Mollusca of the Circumpolar Arctic: a review on their taxonomy, diversity and biogeography

The 3PP marine cave near Marseille (NW Mediterranean) is at a depth of only 15 m. Nevertheless, the cave is a unique deep-sea-like habitat zone due to total darkness, lack of water circulation, oligotrophy, and cold homothermy, a thermal regime similar to that of the deep Mediterranean. We studied the meiofaunal community composition and diversity at 3 sampling stations in the cave (entrance, middle, and blind end). Major taxon composition, based on presence/absence data, did not vary over the transect; however, significant differences in community were found. Tardigrades were the only major taxon restricted to the inner parts of the cave. Copepod diversity decreased towards the inner parts of the cave. The 3PP Cave was characterized by very low abundances of meiofaunal organisms similar to abyssal sites elsewhere. A total of 405 individual copepods were assigned to 27 families and 90 species (75% of them new to science). Significant differences in copepod communities between stations were found at family, genus, and species level. Some harpacticoid taxa generally known from the deep sea, such as Marsteinia, Ancorabolina, Paranannopus, Nematovorax, and Argestidae, were represented in the 3PP Cave. A naive Bayes model was used for the first time to classify the communities as 'shallow' or 'abyssal'. The meiobenthic communities at the entrance and the end of the cave were unequi vocally classified as 'shallow' and 'abyssal' respectively, while the middle part of the cave presented a mixed community. Our study further highlights the strong faunal and community affinities between marine caves and the deep sea, indicating the existence of dispersal mechanisms from deep waters into the euphotic zone for benthic organisms.

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Meiobenthic copepod fauna of a marine cave (NW Mediterranean) closely resembles that of deep-sea communities

The zoogeographic distributions of 1,747 species of shallow-sea benthic Harpacticoida from 370 genera and 51 families reported in the Northern Hemisphere (Atlantic and Arctic Oceans and the European seas) were analyzed. Faunal diversity analysis revealed that the Northeast Atlantic and the North and Mediterranean Seas contain the richest faunas, while certain Arctic regions and internal seas (Caspian, Azov and Aral Seas) are the poorest ones. The distribution of families and genera was also briefly analyzed. Most families are widely distributed (probably cosmopolitan), though others are restricted to boreo-subtropical or even tropical zones, and no purely Arctic families were discovered. Many more genera are present in (or even restricted to) the tropics/subtropics compared with the Arctic/Subarctic zone. Over 15% of species and 55% of genera can be still considered either widespread or cosmopolitan. Cluster-analysis of the regions by species composition revealed six main clusters: Arctic (central Arctic basin, Kara, Laptev, East Siberian, Chukchi and Beaufort Seas), Boreal (North Atlantic Ocean, and North, Baltic, White and Barents Seas), Mediterranean, Ponto-Caspian (Black, Azov, Caspian and Aral Seas), Central East Atlantic, and Central West Atlantic. The distinction between the Mediterranean and Ponto-Caspian faunas is considered in particular, as the latter is not an exact derivative of the Mediterranean one but instead has more atlanto-boreal features. The percent of regional endemics, mean species occurrence and number of families correlate with total species richness, which primarily reflects the degree of exploration in a given region. After removing this effect, the abovementioned features show significant latitudinal trends, with a few endemics present in polar waters. The distribution patterns of different life-forms also vary according to their dispersal abilities. At both global and regional scales, bentho-pelagic forms are the most widely distributed, followed by phytal species, whereas benthic species, especially interstitial, have a more restricted distribution. Overall, our results confirm and statistically validate the main features of marine harpacticoid biogeography asserted a quarter of a century ago by Abele [In: Abele LG (ed) The biology of crustacea. Academic Press, New York, pp 242–304, 1982] and Wells (Syllogeus 58:126-135, 1986).

Large-scale patterns in marine harpacticoid (Crustacea, Copepoda) diversity and distribution

The Chinese mystery snail, Bellamya (Cipangopaludina) chinensis, was recorded for the first time in 2007 in the Netherlands. By 2016, twelve water bodies (mostly riverine ecosystems) had been colonized by this freshwater snail. These records were the first known introductions of this alien species in the European Union (EU). Insight into the invasiveness and (potential) risks of ecological, socio-economic and public health effects of B. chinensis in Europe is urgently needed due to multiple introductions, permanent establishment and continuing secondary spread. A field survey was carried out to determine dispersal rate, habitat conditions and population characteristics of B. chinensis in the floodplain Eijsder Beemden along the river Meuse. The natural dispersal rate in this area was 0.1 km.yr and the average population density was 0.33 individuals.m. This species has colonized several floodplain lakes that are hydrologically connected to the river Meuse. New introductions and colonization of the main channels of large rivers are expected to accelerate the dispersal of this species through water flow and shipping vectors. A risk assessment of B. chinensis was performed using the Harmonia protocol. Evidence of deliberate and unintentional introductions led to a high score for introduction risk. Risk of establishment was also assessed as high. The risk assessment resulted in a medium score for spread risk due to dispersal by human action. The assessed impact on plant targets or animal targets was very low. A medium risk was assigned to impacts on environmental targets. Risk of impacts on human targets received a low score. The overall invasion risk was classified as high and environmental impact was medium, resulting in a medium overall risk score. Regulation of B. chinensis trade and an increase in public awareness about its impact are required to prevent new introductions and further spread of this species in Europe. Moreover, there is an urgent need for research concerning the effects of B. chinensis on native biodiversity and ecosystem functioning, and costeffective management of this species (e.g., eradication, population control and containment measures).

Preferences and bottlenecks: predicting riverine species occurrences under changing abiotic conditions

The invertebrate fauna of rivers and streams of the Southern Yamal has been studied using original specimens (122 bottom and vegetation samples). A total of 158 taxa have been recorded, many of which are new for this region. Among them, 18 types of rheophilic macrobenthic communities have been distinguished which mainly correspond to certain types of habitats and watercourses. A depletion in the set of rheophilic communities (including the loss of almost all crenal and many phytal ones), the taxonomic structure of communities (the loss of large bivalves and most gastropods, hemipterans, and dragonflies), and the total species composition of the fauna, as well as changes in the balance of life forms towards filter feeders (larvae of the family Simuliidae midges and pea clams) and leveling of the differences between the communities of large and small watercourses when compared with the communities of the Russian forest zone, have been recorded. Widespread Eurosiberian species are the most abundant in the rheophilic fauna of the examined region, Arctic species account for ∼20% of all species, and six East Siberian species have been found. No endemic species have been discovered.

The rheophilic fauna and invertebrate communities of the tundra zone: A case study of the Southern Yamal

The fauna composition, ecological groups, and life forms of Harpacticoids of soft littoral grounds from 15 sites off the Karelian coast in Kandalaksha Bay of the White Sea were studied. Six types of harpacticoid taxocens with different sets of dominating species are described. On silty sands with clear signs of desalination, the Stenchelia palustris taxocen is common; medium-grained sands are characterized by the Heterolaophonte minuta, Paraleptastacus kliei — Huntemannia jadensis, and Amphiascoides nanus — Scottopsyllus minor taxocens; while on coarse sands, the Ameira parvula and Ameira scotti — Mesochra lilljeborgi taxocens have developed. The diversity of the taxocens is partly explained by the differences in the grain-size composition and salinity at different sites. In addition, groups of various taxocens dwelling on the same type of the sediments were found in different minor bights of the coastline.

Harpacticoida taxocen diversity in the silty-sandy littoral zone of Kandalaksha Bay of the White Sea

The high Arctic is in a rapid transition due to climate change, and both direct effects due to warming and an extended growing season, as well as an indirect effect caused by increased bird activity and density (notably geese), strongly affect ponds and lakes. Our study presents the hitherto most comprehensive data on invertebrate freshwater diversity at Svalbard and had three main purposes: to provide a current “baseline” of community composition, to compare current species distribution and occurrence with older data to identify changes that have already occurred, and finally to identify how diversity and community composition are related to the age of localities. To address these aims, we conducted a survey of freshwater invertebrates in 75 ponds and lakes at Svalbard in August 2014 and 2015. We provide a full report of the species’ inventory data for zooplankton, benthos, and meiofauna. We also provide data for species that have likely colonized the sites over the previous decades. Finally, our study also clearly demonstrates a diversity gradient related to ecosystem age and/or parameters confounded with age (e.g., productivity), which may hint at the rate of colonization over the time span from the oldest to the youngest localities.

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Freshwater diversity in Svalbard: providing baseline data for ecosystems in change

Changes in trophic state and aquatic communities in high Arctic ponds in response to increasing goose populations

The diversity of shallow-water macrozoobenthic communities is described based on materials con- cerning 11 estuaries of small rivers and streams in the Kandalaksha Bay of the White Sea. Using the Brown- Blanke and cluster analysis techniques, nine types of communities of these estuaries were distinguished depending mostly on the estuary size, salinity, substrate type, water velocity, and depth. In large estuaries, a kind of zonation of the macrobenthic communities along the main estuary axis was observed related to the pro- nounced salinity gradient; it is described in detail for the Chernaya River estuary, which was the most studied. Such zonation is completely absent in small stream estuaries with polypoikilohaline conditions, where a poor species assemblage of brackish-water amphipods of the Gammarus genus dominate. The prevalence of the riv- erine and lacustrine freshwater species (especially of larvae of Diptera and Trichoptera) in the fauna of small estuaries is shown. In contrast, brackish-water and marine species dominate over the majority of the estuarine communities with respect to abundance, while the role of freshwater species is insignificant.

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M. V. Chertoprud

Papers

The rheophilic fauna and invertebrate communities of the tundra zone: A case study of the Southern Yamal

Harpacticoida taxocen diversity in the silty-sandy littoral zone of Kandalaksha Bay of the White Sea

Freshwater diversity in Svalbard: providing baseline data for ecosystems in change

Changes in trophic state and aquatic communities in high Arctic ponds in response to increasing goose populations

Diversity of Macrobenthic Communities in the White Sea Estuaries