Epibionts of an Introduced King Crab in the Barents Sea: A Second Five-Year Study

Venger

Vashchenko

et al. 2023

Biology

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We studied the spatial patterns of the planktonic ecosystems at two Arctic sites strongly affected by Atlantic Inflow (FS, the Fram Strait; and BS, the Barents Sea). A high degree of similarity in the bacterial abundance (mean: 3.1 × 105 cells mL−1 in FS vs. 3.5 × 105 cells mL−1 in BS) was found, while other plankton characteristics were different. Bacterial biomass reached a maximum in BS (3.2–7.9 mgC m−3), while viral abundances tended to be higher in FS (2.0–5.7 × 106 particles mL−1). Larger bacterial cells were found in BS, suggesting the presence of different bacterial populations at both locations. The virus-to-bacteria ratio was significantly higher in FS than in BS (13.5 vs. 4.7). Chlorophyll a concentration was extremely low (<0.25 mg m−3). The highest zooplankton abundance was in the surface layer (919 individuals m−3 in FS vs. 602 ind. m−3 in BS). Zooplankton biomass strongly varied (1–39 mgC m−3), with the maximum in BS. High proportions of boreal taxa in the total zooplankton abundance indicate the Atlantification of pelagic ecosystems in the Arctic. Plankton indicators are correlated with temperature, salinity, and sampling depth. Strong intercorrelations were found between major plankton groups, suggesting tight links in the studied plankton ecosystems.

Section: Introductionmentioning

confidence: 99%

Marine Plankton during the Polar Night: Environmental Predictors of Spatial Variability

Venger

Vashchenko

et al. 2023

Biology

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“…A variety of studies have shown that biotic interactions occur not only between hosts and their symbionts including parasites, but also among symbionts of the same host [ 125 , 126 , 127 ]. Such interactions can play a role in shaping the community structure of co-occurring species [ 128 , 129 , 130 ]. During co-infection, helminth species can demonstrate different types of effects on each other, ranging from dramatically positive and null to dramatically negative, depending on the details of their interaction [ 131 ].…”

Section: Discussionmentioning

confidence: 99%

Helminth Communities of Common Fish Species in the Coastal Zone off Crimea: Species Composition, Diversity, and Structure

Plaksina

Дмитриева²,

2023

Biology

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In this paper, we analyzed the diversity and structure of helminth communities of 12 common fish species from the coastal zone of Crimea. A total of 53 helminth species were found. The total number of parasite species per host fish ranged from 3 to 18. Species richness at the infracommunity and component community levels were from 1.4–4.2 to 1.7–7, respectively. The Brillouin index for the infracommunites was 0.1–1, while the Shannon index for the component communities was 0.3–1.2. Component communities demonstrated a bi- or tri-modal distribution of the parasite prevalence and positive correlations between the prevalence and log-transformed abundance indices, thus following the “core–satellite” conception. Overall, the prevalence and abundance index of the dominant parasite in the component communities ranged from 18 to 80% and from 0.6 to 61.5 ind. per fish, respectively. The structure of the helminth component communities demonstrated good accordance with the nestedness mode where the rarest species occurred in the most diverse infracommunities, while the poorest infracommunities were composed of a few dominating species. More than two-thirds of the studied helminth species had an aggregated distribution indicating well-structured and developed communities. Our data provide a basis for further research and may be used for fish resource monitoring and management.

“…Weaker organic matter fluxes were observed at Stations 4, 5, 6, 15, and 17, where foraminiferal sand and thick layers of brown silt were found overlaying a lower layer of brown clay. In comparison, more robust sedimentation processes occurred at Stations 10,11,12,and 20. These stations exhibited a thin layer of sediment overlaying gray sediments, and a poor postmortem preservation of foraminifera was noted.…”

Section: Environmental Conditionsmentioning

confidence: 94%

“…The first, transformed Barents Sea water (BSW), is primarily composed of Atlantic water (AW) which has undergone heat loss. This water mass was detected at eight sampling stations ( Stations 4,5,6,10,11,12,15,and 20) characterized by negative water temperatures and a salinity of 34.9 psu. The second water mass, Arctic water (ArW), was observed at Station 17, with lower temperature and salinity levels compared to the BSW.…”

Section: Environmental Conditionsmentioning

confidence: 99%

“…These benthic organisms are closely associated with large-scale water column processes that dictate the availability of food resources reaching the underlying sediments [8]. As the community patterns of these organisms are directly influenced by the exportation of organic matter from the overlying water column, benthic communities serve as long-term integrators of water column processes that can reflect different hydrographic regimes [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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The Impact of Sea Ice Loss on Benthic Communities of the Makarov Strait (Northeastern Barents Sea)

Павлова

Frolov

et al. 2023

Animals

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The continental shelf of the northeastern Barents Sea is presently experiencing a weak influx of Atlantic water from the west. In recent times, warming in Arctic regions has led to an increase in extended ice-free periods in this area, instead of significantly elevating water temperatures. The implications of this phenomenon on the structure and functioning of benthic communities were investigated during the autumn of 2019 within the Makarov Strait, located in the southwestern part of the St. Anna Trough. The macrozoobenthic communities exhibited a clear connection with the duration of ice-free periods. This variable influenced a vertical carbon flux, which subsequently served as the primary predictor for faunal abundance and diversity, as demonstrated by redundancy and correlation analyses. Two faunal groups were identified, corresponding to short and long open-water periods. Both groups had similar alpha diversity (65 ± 6 and 61 ± 9 species per station) and biomasses (39 ± 13 and 47 ± 13 g m−2) but displayed differing abundances (1140 ± 100 vs. 4070 ± 790 ind. m−2) and other diversity indices. We observed a decline in the proportion of polychaetes, accompanied by an increase in the proportion and diversity of bivalves, as well as a rise in the abundance of infaunal species, sub-surface deposit feeders, and mobile suspension feeders, in response to the increasing vertical carbon flux. The potential increase in anthropogenic pressures related to oil development in the northeastern Barents Sea highlights the importance of our study for conservation and monitoring efforts in the region.