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Macrozoobenthic communities provide vital ecosystem services including habitats and foraging resources for other species in all marine ecosystems. Although macrozoobenthos of deeper parts of the Pechora Sea (SE Barents Sea) have been studied in more detail, there is a lack of research in shallow waters of the Pechora Bay. The study area lies within the Nenetsky State Nature Reserve, established in 1997, to protect important breeding and moulting grounds of waterfowl. Macrozoobenthos provide key foraging resources for waterfowl in the nature reserve, however, there is a mismatch between ornithological and macrobenthic data. Eight stations were studied along the Russky Zavorot Peninsula in the Pechora Bay on a depth of 1.1–1.8 m within the near-shore zone of the Nenetsky State Nature Reserve in August 2016. A monodominant community of Limecola balthica with a biomass of 21.31 ± 0.32 g/m2 and 14 species in total was recorded across the area. The dominant species of the community correspond to those in the community of L. balthica recently described from the central estuarine part of the Pechora estuary. A low biomass and poor species richness in the L. balthica community support the earlier published results for the northern part of the bay and indicate the dependence of the community characteristics on environmental factors. The paucity of macrozoobenthos in the area is likely attributed to extreme environmental conditions including the following: (1) the water column freezes to the bottom during winter in the shallows of the Pechora estuary or (2) the freshwater flow spreads under the ice, severely impacting salinity. Hence the community is comprised of eurythermal and euryhaline forms and is reduced in biomass. It is unlikely that the shallows of the Russky Zavorot Peninsula play an important role as feeding grounds for benthic predators since a low in biomass barren community of a burrowing mollusc L. balthica does not provide enough foraging resources to feed stocks of waterfowl. The L. balthica-community could be used as an indicator of climate changes in the future – it is predicted that a reduction in sea ice volume will improve conditions for growth of L. balthica and may therefore lead to an increased body size and biomass of bivalves in the shallows.
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Nature Conservation Research. Заповедная наука 2019. 4(4)
Anna A. Gebruk1,2, Polina B. Borisova3, Milana A. Glebova2, Alexander B. Basin3,
Miloslav I. Simakov3, Nikolay V. Shabalin2, Vadim O. Mokievsky3
1University of Edinburgh, United Kingdom
2Marine Research Centre of Lomonosov Moscow State University, Russia
3Shirshov Institute of Oceanology of RAS, Russia
Received: 16.03.2018. Revised: 01.08.2019. Accepted: 02.08.2019.
========== ОРИГИНАЛЬНЫЕ СТАТЬИ ===========
============= R E S E AR C H A RT I C L ES =============
Macrozoobenthic communities provide vital ecosystem services including habitats and foraging resources for
other species in all marine ecosystems. Although macrozoobenthos of deeper parts of the Pechora Sea (SE Bar-macrozoobenthos of deeper parts of the Pechora Sea (SE Bar-
ents Sea) have been studied in more detail, there is a lack of research in shallow waters of the Pechora Bay. The
study area lies within the Nenetsky State Nature Reserve, established in 1997, to protect important breeding and
moulting grounds of waterfowl. Macrozoobenthos provide key foraging resources for waterfowl in the nature
reserve, however, there is a mismatch between ornithological and macrobenthic data. Eight stations were studied
along the Russky Zavorot Peninsula in the Pechora Bay on a depth of 1.1–1.8 m within the near-shore zone of
the Nenetsky State Nature Reserve in August 2016. A monodominant community of Limecola balthica with a
biomass of 21.31 ± 0.32 g/m2 and 14 species in total was recorded across the area. The dominant species of the
community correspond to those in the community of L. balthica recently described from the central estuarine
part of the Pechora estuary. A low biomass and poor species richness in the L. balthica community support the
earlier published results for the northern part of the bay and indicate the dependence of the community charac-
teristics on environmental factors. The paucity of macrozoobenthos in the area is likely attributed to extreme
environmental conditions including the following: (1) the water column freezes to the bottom during winter in
the shallows of the Pechora estuary or (2) the freshwater ow spreads under the ice, severely impacting salinity.
Hence the community is comprised of eurythermal and euryhaline forms and is reduced in biomass. It is unlikely
that the shallows of the Russky Zavorot Peninsula play an important role as feeding grounds for benthic preda-
tors since a low in biomass barren community of a burrowing mollusc L. balthica does not provide enough forag-
ing resources to feed stocks of waterfowl. The L. balthica-community could be used as an indicator of climate
changes in the future – it is predicted that a reduction in sea ice volume will improve conditions for growth of L.
balthica and may therefore lead to an increased body size and biomass of bivalves in the shallows.
Key words: Arctic, biomass, estuary, Limecola balthica, macrobenthic community
The Arctic Ocean has one of the most sensi-
tive to environmental changes ecosystems on Earth
(Spiridonov et al., 2012). Declines in sea ice thick-
ness in the Arctic Ocean, along with an increase in air
temperature, ocean acidication and anthropogenic
pressures from oshore industries lead to changes in
the marine ecosystems of the Arctic regions (Kwok
& Rothrock, 2009). The benthic fauna is often used
to observe contemporary changes in the environ-
ment, since various environmental factors including
the availability of organic matter and water temper-
ature, as well as human activities, have direct impact
on biomass and the composition of macrozooben-
thos assemblages (Denisenko et al., 2003; Hinz et
al., 2009). Recent publications revealed that benthic
invertebrates also tend to ingest and accumulate mi-
croplastics from the water column (Courtene-Jones
et al., 2017; La Beur et al., 2019). Hence, there is a
need for expanding the current knowledge on mac-
robenthos, especially in the Arctic regions.
The Pechora Sea in the southeast (SE) basin of
the Barents Sea is characterised by shallowness, a
specic hydrological regime and by an intense o-
shore oil and gas exploration and production (Den-
isenko et al., 2003). The macrozoobenthos of the
Pechora Sea accounts for approximately 35% of the
benthic biodiversity in the Barents Sea and is gener-
ally well-described for the deeper waters; however,
there is a lack of data for the near-shore areas (Dahle
et al., 1998; Denisenko et al., 2003; Kucheruk et al.,
2003; Sukhotin et al., 2008; Denisenko N. et al.,
2019). The macrozoobenthos of the Pechora Sea is
characterised by a high variability in spatial distribu-
tion («mosaic pattern») caused by alterations of sea-
oor topography and sediment types. Presumably
this is also applicable for the Pechora Bay (Dahle et
al., 1998; Denisenko et al., 2003).
The study area is within the Pechora Bay, the
large estuarine ecosystem that assures a huge pro-
portion of continental runo into the Barents Sea
region. The Pechora Sea receives approximately
2.5 million tonnes of terrigenous sediments annu-
ally through the Pechora estuary (Dobrovolsky
& Zalogin, 1982). The Pechora Bay is character-
ised by a broad intertidal zone, with a tide height
of 1.1–1.5 m (Byshev et al., 2003; Denisenko N. et
al., 2019). The ice thickness in winter reaches 1.5
m, freezing to the bottom of the shallow near-shore
areas of the bay. Sediments in the bay are formed
by clayey sands and are inuenced by a continental
runo and permafrost abrasion (Denisenko N. et al.,
2019). The latest review of macrozoobenthos of the
Pechora Bay was by Denisenko N. et al. (2019) and
was based on samples collected in 1995. Twenty-
two sites from a depth range of between 5 m and 18
m were studied in the north-east and central areas
of the bay. Overall, the most common was a typi-
cal estuarial assemblage with a strong dominance of
Limecola balthica Linnaeus, 1758 (occurring at 9 of
22 sites). The L. balthica-community described by
Denisenko N. et al. (2019) had a mean biomass of
130.3 ± 64.8 g/m2 and comprised 34 species in total.
The study area lies within the 1st zone of the
Nenetsky State Nature Reserve named «Pechora
river estuary and a 2 km water territory surround-
ing the Russky Zavorot peninsula». The Nenetsky
State Nature Reserve covers the River Pechora es-
tuary and nearby islands. In total the state nature
reserve covers an area of 3134 km2 of which more
than a half (1819 km2) corresponds to marine areas
(Nenetsky Zapovednik, 2019). To safeguard the
area from rapidly developing industrial activities,
a state nature reserve was established in 1997. The
main aim of establishing the nature reserve was the
protection of important habitats for waterfowl that
stopover in shallow waters of the Pechora Sea dur-
ing their migration from reproduction sites in West
Siberia to variable wintering sites (Sukhotin et al.,
2008). The Nenetsky State Nature Reserve pro-
vides nesting and feeding grounds, and forms part
of the migration routes for 125 species of water-
fowl and coastal birds. This includes species from
the Red Data Book of the Russian Federation and
IUCN Red List of threatened species, such as: the
yellow-billed loon Gavia adamsii Gray, GR, 1859;
Bewick’s swan Cygnus columbianus bewickii Ord,
1815; the lesser white-fronted goose Anser albi-
frons Scopoli, 1769; the red-breasted goose Branta
rucollis Pallas, 1769 (IUCN, 2019).
Common species, such as the king eiders (So-
materia spectabilis Linnaeus, 1758), form abundant
ocks of up to tens of thousands of individuals to
feed and molt before migrating to wintering grounds
(Krasnov et al., 2002). Marine ducks, including king
eiders, are specialised benthic feeders and their main
prey items are bivalves (Sukhotin et al., 2008). For-
aging macrobenthos were studied near the coasts of
the Dolgy Island (Sukhotin et al., 2008; Denisenko
S. et al., 2019). A mismatch between ornithological
and macrobenthic data for the region was rst noted
by Sukhotin et al. (2008). However, macrobenthic
assemblages have previously never been studied in
the shallows of the continental shore of the Nenet-
sky State Nature Reserve. For the open-sea, sandy
shallows (5–7 m deep) of the Medynsky Zavorot
Peninsula, between the mouth of Pechora Bay and
Dolgy Island, a community dominated by Limecola
balthica (previously known as Macoma balthica
Linnaeus, 1758) was described at several stations
(Kucheruk et al., 2003). The biomass of benthos in
this community was low (ca. 3 g/m2) and species
diversity was scarce (totally16 species and 1–8 spe-
cies per sample), explained by a strong wave action.
Ultimately, there are no macrobenthic data
available for continental shores of the Protected
Area. The present study aimed at fullling the
knowledge gap on shallow-water macrozoobenthos
of the Nenetsky State Nature Reserve by describing
macrozoobenthic assemblages of the Pechora Bay
and comparing them to other Arctic estuarine com-
munities. The results can be used as a baseline data
for further conservation or spatial planning activi-
ties in the area.
Material and Methods
Site description
Benthic samples were collected between 24th
and 30th August 2016 in the Nenetsky State Nature
Reserve from the inner (southern) bay of the Russky
Zavorot peninsula (Fig. 1A). The inner coastline of
the Kuznetskaya inlet forms a shore of the Pechora
Bay and is comprised of wetlands, protected from
the waves and covered by vegetation (Fig. 1C).
Tides on the inner shore are regular, semi-diurnal
with a range of 1–1.5 m. Bottom sediments were
formed of homogeneous sand with silts across the
whole sampling area (Appendix 1).
Nature Conservation Research. Заповедная наука 2019. 4(4)
Fig. 1. Map of the study area. A: Study area (black rectangular) and territory under protection of the Nenetsky State Nature
Reserve (green hatching). B: Sampling sites with bathymetry data shown for each site. C: Typical view of the swamped south-
ern shore of the peninsula open to the Kuznetskaya inlet.
Samples were taken at 8 stations in 3 replicates
from each site in the depth range between 1.1 m to
1.8 m at low tide from a rubber motorboat with a
hand shovel with capture volume of 0.05 m2. Sedi-
ments were washed over a mesh size of 0.5 mm with
sea water, then pre-xed with 4% formaldehyde.
In the laboratory, pre-xed animals were man-
ually sorted out of the organic debris of the samples
for species identication, studied and re-xed in
70% ethanol solution. Macrobenthic invertebrates
were studied and photographed under a binocu-
lar microscope Leica165C and identied with the
maximum level of certainty. All the species names
were given in accordance to the World Register of
Marine Species (WoRMS). For each sample iden-
tied taxa were counted and weighed on a Jewelry
Scale ML-CF3 to mg, unidentied fragments were
also weighed and recorded as «Varia».
Polychaeta fragments were counted both in an-
terior and posterior fragments and the bigger value
chosen for each species. Bivalve molluscs were
weighed with exoskeleton.
Microsoft Excel and software PAST (version
2.17) were used for data analysis (Hammer et al.,
2001; Hammer & Harper, 2006). Non-transformed
data were used.
Standard diversity indices were used to charac-
terise diversity (dominance, Simpson index, Shannon
index, Chao2), all calculations were performed using
PAST software package (Hammer & Harper, 2006).
Species accumulation curve or sample-based
rarefaction was used to assess how samples repre-
sent biodiversity (species richness) predicted in the
area. The predicted species richness ( ) computed
with Chao2-type estimator following Colwell et al.
(2004), species accumulation curve was plotted in
PAST with 95 percent condence intervals (Ham-
mer & Harper, 2006):
where H – samples, Sobs – the total number of
observed species and S1 – the number of species
found in exactly one sample.
Nature Conservation Research. Заповедная наука 2019. 4(4)
Mean values ± standard error are given for bio-
mass and abundance.
Determination of macrozoobenthic assem-
blages was based on biomass values. Species with
the largest contribution to biomass at each station
were considered as dominants, second and third
largest – as subdominants.
Classical hierarchical clustering based on paired
group (UPGMA) algorithm and non-metric multidi-
mensional scaling (MDS) both based on Bray-Cur-
tis similarity index (Hammer & Harper, 2006) were
used to reveal whether the benthos across the sites
formed distinct communities (groups). The Similar-
ity percentage (SIMPER) was applied to assess taxa
contribution to dierences between the groups. The
one-way analysis of similarities (ANOSIM) with
Bonferroni-corrected p-values following Hammer
& Harper (2006) was used to estimate the signi-
cance of dierences between the groups. The Pear-
son coecient (r) was applied to assess correlations
with environmental variables.
Maps were designed in ESRI ArcMap 10.4.1
using the standard GIS tools provided by the soft-
ware. The reference coordinate system WGS84
and Universal Transverse Mercator projection
(zone 40N) were used.
A total of 14 taxa of benthic invertebrates were
identied in 24 samples from 8 stations, 12 taxa
identied to species level (Table 1). The fauna was
mainly comprised of crustaceans (5 species), poly-
chaetes (4 species) and bivalves (3 species), and with
a single species of Priapulida and Insecta. Bivalves
were the dominant group in both total biomass and
abundance. The mean biomass of the macrobenthic
invertebrates in the area was 21.31 ± 0.32 g/m2 and
the mean abundance was 2131 ± 1825 individuals
per m2 (ind/m2). Primary data on abundance, bio-
mass and number of species per sample are present-
ed in Appendix 1. A taxonomic matrix of species
with images of the specimens is in Appendix 2.
The Shannon diversity was low (H’ = 1.26), mac-
rozoobenthos was represented by a small number of
taxa with a few individuals and astrong dominance
of one species (Table 2). The predicted number of
species was the same as discovered (Chao-2 rich-
ness = 14.19). The biodiversity was represented close
to equally between the stations: four species had
100% occurrence in the study area, and only one spe-
cies had < 20% occurrence (Table 1).
The species accumulation curve approached the
plateau at the level of 7 stations, reaching 14 species
(Fig. 2). The discovered diversity of macrozooben-
thos was therefore fully representative for the area.
The hierarchical clustering and MDS plots
showed three groups of stations in the study area
(Fig. 3). Group A consisted of stations 5, 7 and 8;
group B included stations 2, 3 and 6; and station 1
formed a separate group.
ANOSIM analysis showed statistically signicant
dierence between group A and B (Table 3, p < 0.05).
Table 1. Species composition of macrozoobenthos and mean values of biomass (g/m2) and abundance (ind./m2) of each
species in the study area in 2016
group Species Mean biomass for the
study area, g/m2
Mean abundance for
the study area, ind./m2
Frequency of oc-
currence across
Bivalvia Cyrtodaria kurriana Dunker, 1861 0.18 ± 0.004 10.83 ± 0.21 0.5 m, b
Bivalvia Limecola balthica L.1758 17.29 ± 0.19 762.50 ± 7.54 1 m
Bivalvia Yoldia hyperborea Gould, 1841 2.87 ± 0.09 595.00 ± 8.05 1 m
Crustacea Saduria entomon Linnaeus, 1758 0.05 ± 0.001 2.500 ± 0.07 0.38 m, b
Crustacea Monoporeia anis Lindstrцm, 1855 0.006 ± 0.001 2.500 ± 0.07 0.25 b, f
Crustacea Pontoporeia femorata Krшyer, 1842 0.001 ± 0.001 0.833 ± 0.04 0.16 m, b
Crustacea Monoculodes sp. Stimpson, 1853 0.003 ± 0.001 4.167 ± 0.13 0.38 m
Crustacea Diastylis sulcata Calman, 1912 0.005 ± 0.001 6.667 ± 0.13 0.75 m, b
Insecta Chironomidae gen.sp. 0.002 ± 0.003 1.667 ± 0.06 0.25 m
Polychaeta Eteone agg. ava Fabricius, 1780 0.09 ± 0.001 31.667 ± 0.32 1 m
Polychaeta Laonice cirrata M. Sars, 1851 0.001 ± 0.001 0.833 ± 0.04 0.13 m, b
Polychaeta Micronephthys minuta Thйel, 1879 0.009 ± 0.007 6.667 ± 0.09 0.63 m
Polychaeta Spio armata Thulin, 1957 0.57 ± 0.007 686.667 ± 7.39 1 m
Priapulida Halicryptus spinulosus von Siebold,
1849 0.17 ± 0.001 1.667 ± 0.06 0.25 m
Note: *Typical habitats are presented according to WoRMS with corrections (Filatova & Zenkevich, 1957; Zhirkov, 2001): m – marine,
b – brackish, f – fresh.
Nature Conservation Research. Заповедная наука 2019. 4(4)
Fig. 2. Sample rarefaction (Mao’s tau): red line – accumulat-red line – accumulat-
ed number of species, blue line – 95% condential interval,
black dotted line – number of species found in the samples.
Table 2. Key characteristics of macrozoobenthic diversity in
the study area: number of taxa, number of individuals, domi-
nance, Simpson diversity, Shannon diversity, estimated spe-
cies richness (Chao-2 metric)
Diversity indices Values of diversity
Taxa_S 14
Individuals 2537
Dominance_D 0.3151
Simpson_1-D 0.6849
Shannon_H 1.262
Chao-2 14.19
Fig. 3. Groups of stations in the study area determined by the hierarchical clustering (carried out on macrozoobenthic biomass
data) (A) and MDS (B). Three groups can be seen: A – stations 5, 7 and 8, (purple shading); B – stations 2, 3, 4 and 6 (green
shading); C – station 1.
Table 3. Pairwise comparison of groups of stations with
ANOSIM analysis, Bonferroni-corrected p-values and R-
values shown
Group B
Group A p = 0.0283; R = 1
The variation in biomass of three species of bi-
valves (Limecola balthica, Yoldia hyperborea Gould,
1841 and Spio armata Thulin, 1957) assured dierence
between the stations as shown by SIMPER analysis (Ta-
ble 4). The biomass of the bivalve L. balthica accounted
for 83.7% contribution to the dissimilarity between the
groups. Despite the statistical dierence between the
groups of stations, L. balthica remained the dominant
species for all of the stations in the study area and dif-
ferences were likely caused by natural variation in spa-were likely caused by natural variation in spa-
tial distribution of the biomass of the common species.
The macrozoobenthos in the study area was therefore
formed by a monodominant community of L. balthica.
The species composition of each station and
spatial distribution of the macrozoobenthos biomass
(g/m2) across the study area are shown in Fig. 4. The
biomass of macrozoobenthos per station had no cor-
relation with the depth range (r = -0.45, p = 0.2).
The macrozoobenthos of the Pechora Sea has
been studied over nearly a hundred years (Zenk-
evich, 1927; Dahle et al., 1998; Denisenko S. et
al., 2003, 2019; Kucheruk et al., 2003; Sukhotin
et al., 2008; Denisenko N. et al., 2019). However,
the vast majority of benthic surveys in this region
were conducted on-board large research vessels
at depths greater ~10 m. Hence there is a lack of
macrozoobenthic data for near-shore and estua-
rine zones. This is also true for most of the Arc-
tic zones, where shallow estuarine ecosystems are
usually out of focus of big surveys.
Nature Conservation Research. Заповедная наука 2019. 4(4)
Table 4. Species contribution to dissimilarity between groups of stations produced by SIMPER analysis (only taxa with >1%
contribution shown)
Taxon Average dissimilarity Contribution % Cumulative % Group A Group B
Limecola balthica 78.56 83.7 83.7 0.091 4.65
Yoldia hyperborea 11.38 12.13 95.83 0.073 0.793
Spio armata 1.902 2.027 97.85 0.005 0.113
Fig. 4. Biomass (g/m2) and dominant species of invertebrates on the sampling sites.
The present study provides the rst detailed
report on macrozoobenthos of the continental shal-
lows of the Nenetsky State Nature Reserve, al-
though macrozoobenthos of the central and north-
ern parts of the Pechora estuary were discussed in
a recent publication by Denisenko N. et al. (2019).
The authors sampled twenty estuarine sites in the
Pechora Bay during the RV Geophysic cruise in
spring 1995 and compared the Pechora Bay macro-
zoobenthos with that of the Ob bay in the Kara Sea
(Denisenko et al., 1999). Recently Denisenko N. et
al. (2019) reviewed their data.
Despite the small number of species found in
the present study, the biodiversity of the macrozoo-
benthos was representative for the study area since
it matched the predicted species richness (Chao-
2 = 14.19, n = 14). Estuaries are typically character-
ised by lower biodiversity of macrobenthic inver-
tebrates compared to marine environments. Ratios
between marine, estuarine and freshwater species
in the composition of estuarine macrozoobenthos
typically depend on the salinity of a particular site
(Whiteld et al., 2012). The River Pechora estuary
is characterised as a mesohaline zone with low spe-
Nature Conservation Research. Заповедная наука 2019. 4(4)
cies richness (Denisenko N. et al., 2019). The spe-
cies richness is aected more by the granulometric
sediment structure than organic matter content of
sediments or water salinity variations within the
Pechora estuary (Denisenko N. et al., 2019). In the
present study the fauna was comprised of marine
species with a few brackish crustaceans. At least
one brackish species was present at each station.
Monoporeia anis Lindstrцm, 1855 and Saduria
entomon Linnaeus, 1758, occurred with the fre-
quency of 0.38 (recorded for stations 7 and 8) and
0.25 (stations 1, 2 and 8) respectively.
Macrobenthos communities in the study area
were dominated by Limecola balthica with the
mean biomass of 21.31 ± 0.32 g/m2 (varying from
1.33 g/m2 on station 1 to 43.17 g/m2 on station 2),
and a total of 14 species. The observed dierences
in biomass between the stations were presumably
a statistical artefact caused by natural variation in
spatial distribution of biomass across the bay since
the structure of dominance remained the same
across the study area. Sediments also were the
same across the study area supporting consistency
of the benthic community. However, we acknowl-
edge that an increasing research area would give a
better understanding of the consistent patterns of
species distribution across the bay.
In 1995, Denisenko N. et al. (2019) revealed
ve types of macrobenthic communities in the
central and northern parts of the bay, as opposed
to the only one observed in the present study. Of
these ve types, the community dominated by L.
balthica was the most common overall and was
characterised by the authors as typical for muddy-
sand bottoms at depths of 510 m in the central
part of the bay, with a strong dominance of L. bal-
thica, a total of 34 species, moderate abundance
and a biomass of 130.3 ± 64.8 g/m2 (Denisenko N.
et al., 2019). As for diversity, the majority of spe-
cies found in the present study were also present in
Denisenko’s L. balthica-community, except for the
following: Chironomidae gen.sp., Laonice cirrata
M. Sars, 1851, Spio armata and Yoldia hyperbo-
rea. All these species are typical for shallow water
and often found in terrigenous coastal muds. The
closest to our study area site sampled in 1995 was
site 24 characterised by the L. balthica-community
with a biomass of 21.9 ± 1.8 g/m2.
The study area is characterised by extreme
environmental conditions for macrozoobenthos,
e.g. an ice thickness up to 1.5 m with most habi-
tats at depths 1–2 m freezing to the bottom. The
inner shore of Russky Zavorot Peninsula is isolat-
ed from wind-drift convection and is most prob-
ably impacted by the River Pechora run o. Fur-
thermore, in semi-isolated near-shore areas in the
Arctic, continental stock in winter forms a fresh-
water outow that spreads under the ice, forming
a layer of fresh water, forcing marine macrozoo-
benthos to move deeper into sublittoral zones, as
was also described for the Canadian Arctic (Ellis,
1995). Therefore, the macrobenthic richness in
the area is limited by ice thickness and freshwa-
ter impact and is comprised of eurythermal and
euryhaline forms, tolerant to uctuations in both
temperature and salinity. The sea ice thickness
and under-ice freshwater impact are common
limitation factors for intertidal and upper sublit-
toral zones in the Arctic shallows (Mokievsky et
al., 2016). Ultimately the community in the study
area corresponds to the community with a domi-
nance of L. balthica determined by Denisenko N.
et al. (2019), though with lower richness and a
biomass due to extreme conditions.
A further reduction of the Limecola-commu-
nity was reported from the open shores of the Pe-
chora Sea (Kucheruk et al., 2003). Biomass values
in this area were even lower than in the present
study, whilst among driving factors of macroben-
thic distribution authors emphasised not the ice
thickness or freshwater input, but wind waves that
disturb sea bottom down to several meters depth
as it has been shown for shallowness near Dolgy
Island (Denisenko S. et al. 2019). As in the present
study, the dominant species were also represented
by abundant juveniles only (up to 1000 ind/m2)
with a complete lack of adults.
Limecola balthica is an infaunal bivalve mol-
lusc with a circumpolar distribution, common in
the intertidal zones and estuaries, often dominant
in soft bottom communities (Väinölä & Varvio,
1989). In the Arctic region, L. balthica is dominant
within the Pechora Bay as a relict species. A com-
munity with dominance of L. balthica and Cyrto-
daria kurriana Dunker, 1861 was also described
from the shallows of Baydara Bay (Kucheruk et al.,
1998), but it was absent in typical Arctic estuaries,
such as the Ob Bay in the Kara Sea in 1995 (Den-
isenko et al., 1999). Limecola balthica is evidently
sensitive to the climate change, as was shown for
stock from the western Wadden (North) Sea where
an increase in water temperature resulted in a lower
reproductive output and an earlier spawning period
(Philippart et al., 2003).
Among the most common waterfowl of the
Nenetsky State Nature Reserve is the king eider
Nature Conservation Research. Заповедная наука 2019. 4(4)
that feeds on macrobenthic invertebrates, often
molluscs (Brun, 1971; Lovvorn et al., 2003; Mer-
kel et al., 2007). It was shown for Dolgy Island in
the Pechora Sea that marine ducks including the
king eider were predominantly feeding on mussels
Mytilus edulis Linnaeus, 1758, that were unreach-
able for traditional techniques of benthic research
and therefore often underestimated (Sukhotin et
al., 2008). Unlike the Dolgy Island research area,
in the Russky Zavorot Peninsula any rock outcrops
or fragments of mussel shells were not recorded
during the present study. It is unlikely that the
Limecola balthica-community in the shallows of
Russky Zavorot peninsula provides enough forag-
ing resources to sustain big stocks of waterfowl.
It has been repeatedly predicted in the lit-
erature that increasing temperatures in the Arctic
will aect benthic communities, which could lead
to changes in species distribution and interaction,
allow the introduction of new species, and en-
able a decrease of arctic species alongside with
an increase of boreal species in the composition
of benthic fauna (Lambert et al., 2010; Josefson
et al., 2013; Renaud et al., 2015). The Barents Sea
has been identied as a hotspot for «atlantica-
tion» of seawater and the expansion of boreal spe-
cies (Renaud et al., 2015; Vihtakari et al., 2018).
It is likely that eects of climate change on the
macrozoobenthos of the Pechora Bay will appear
in the foreseeable future. In the study area, the
thickness of sea ice is a key limitation factor for
macrozoobenthos, therefore reduction of the sea
ice volume would likely improve conditions and
habitat availability for the L. balthica-community
which leads to increasing the body size and bio-
mass of molluscs inhabiting shallows. To achieve
a broader understanding of the biomass trends of
L. balthica stock in Nenetsky State Nature Re-
serve near-shore areas, the present study can be
considered as a baseline with further regular ob-
servations required.
A сommunity of macrobenthic invertebrates
with a mean biomass of 21.31 ± 0.3 g/m2, strongly
dominated by L. balthica, and comprising a total
of 14 species, was described based on 8 stations
in the shallows of the Russky Zavorot Peninsula
at a depth of 1.1–1.8 m in August 2016. This is the
rst study of the benthos of the continental shal-
lows of the Nenetsky State Nature Reserve. All
studied sites were characterised by a muddy-sand
substrate. The observed community represents a
form reduced in richness and biomass of the L.
balthica-community, described by Denisenko N.
et al. (2019) from the central and northern parts of
the River Pechora estuary. At the periphery of its
distribution, the community is attributed to sea ice
thickness and freshwater impact and is therefore
comprised of eurythermal and euryhaline forms.
Species occurring in the shallows but absent in
deeper habitats described by Denisenko N. et al.
(2019) included Chironomidae gen.sp., Laonice
cirrata, Spio armata, and Yoldia hyperborea.
It is unlikely that the shallows of Russky Za-
vorot Peninsula play an important role as feeding
grounds for benthic predators since a barren com-
munity of L. balthica does not produce enough for-
aging biomass. The state of the L. balthica-commu-
nity can be used as an indicator of climate change
in the future. We suggest that with a reduction in
the volume of sea ice it is likely that conditions and
habitat availability for the L. balthica-community
will improve in the shallow waters, and this could
lead to an increased size and biomass of bivalves.
However, to gain a better understanding of L. bal-
thica biomass dynamics in the Pechora Bay, more
regular observations are required in both near-
shore and open water areas.
The studies undertaken up until now within the
marine borders of the Nenetsky Reserve are still
rather scarce and do not cover the whole range of
shallow water habitats. As for many other marine
reserves in the Arctic, there is an urgent need for
detailed habitat mapping and diversity estimations.
The authors express their gratitude to the adminis-
tration and sta of the Nenetsky State Nature Reserve
for enabling data collection. We gratefully acknowledge
all involved in eldwork (Evgeniy Snytnikov, Michael
Borovskiy, Evgeniy Ezhelya – all are from Lomonosov
Moscow State University) and processing of the samples
(Milena Khutoryanskaya). We also thank Lea-Anne Henry
and Nadia Jogee (Changing Oceans Group, University of
Geosciences), Dr. Andrey Gebruk (Shirshov Institute of
Oceanology of RAS) and anonymous reviewers for giv-
ing helpful feedback. The study is partly supported by the
RFBR grant 18-05-60053.
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Appendix 1. Primary data on abundance, biomass and number of species of macrozoobenthos collected in the Pechora Bay in 2016.
Co-ordinates Depth, m Abundance,
g/m2Number of species Sediments
68.897778 53.634167 1.6
60 1.06 2 Muddy sands
1-2 1080 2.02 8 Muddy sands
1-3 640 0.92 2 Muddy sands
68.896111 53.659444 1.1
1160 0.92 4 Muddy sands
2-2 4500 98.6 7 Muddy sands
2-3 3940 29.98 6 Muddy sands
68.896667 53.695556 1.3
8400 10.68 5 Muddy sands
3-2 2100 34.16 8 Muddy sands
3-3 3140 43.82 6 Muddy sands
68.898611 53.736944 1.2
1760 44.84 6 Muddy sands
4-2 3380 33.78 8 Muddy sands
4-3 3860 38.54 7 Muddy sands
68.905278 53.755278 1.1
1580 5.3 5 Muddy sands
5-2 2900 13.52 5 Muddy sands
5-3 2860 7.78 6 Muddy sands
68.915833 53.782778 1.4
1600 18.56 7 Muddy sands
6-2 1960 62.44 7 Muddy sands
6-3 1960 37.2 5 Muddy sands
68.920278 53.799167 1.2
560 2.86 3 Muddy sands
7-1 680 3.4 6 Muddy sands
7-3 1140 5.86 5 Muddy sands
68.914444 53.820000 1.8
840 5.58 5 Muddy sands
8-2 620 2.84 5 Muddy sands
8-3 420 6.56 3 Muddy sands
Nature Conservation Research. Заповедная наука 2019. 4(4)
Appendix 2. Taxonomic matrix of species with images taken under the binocular microscope.
А. А. Гебрук1,2, П. Б. Борисова3, М. А. Глебова2, А. Б. Басин3,
М. И. Симаков3, Н. В. Шабалин2, В. О. Мокиевский3
1Университет Эдинбурга, Великобритания
2Цетр морских исследований МГУ им. М.В. Ломоносова, Россия
3Институт океанологии им. П.П. Ширшова РАН, Россия
Сообщества макрозообентоса выполняют жизненно важные функции во всех морских экосистемах,
в том числе формируя местообитания и пищевые ресурсы для других видов. Несмотря на то, что ма-
крозообентос более глубоких участков Печорского моря (юго-западная часть Баренцева моря) в целом
изучен достаточно детально, мелководные участки, в частности Печорская губа, изучены значительно
хуже. Район исследований данной работы находился на территории Ненецкого государственного запо-
ведника, основанного в 1997 г. с целью охраны ключевых районов кормления и линьки для морских
птиц. Макрозообентос формирует основу пищевых ресурсов для морских птиц на территории Ненецкого
заповедника, но в литературе наблюдается явный дисбаланс между количеством опубликованных орни-
тологических и гидробиологических данных. В данной работе был исследован макрозообентос восьми
станций, собранный в августе 2016 г. вдоль побережья полуострова Русский Заворот внутри охраняемых
вод Ненецкого заповедника на глубине 1.1–1.8 м. Для всех станций описано монодоминантное сообще-
ство Limecola balthica со средней биомассой 21.31 ± 0.32 г/м2 и 14 видами макрозообентоса. Доминант-
ные виды описанного сообщества совпадают с сообществом L. balthica, недавно описанным в литературе
для центральной части Печорской губы. Низкая биомасса и видовое разнообразие сообщества L. balthica
в исследуемом районе соответствуют ранее полученным данным для северной части эстуария. Они под-
тверждают гипотезу зависимости состояния сообщества от условий среды. Бедность макрозообентоса в
районе работ вероятно связана с экстремальными условиями обитания, включающими (1) промерзание
грунта на этих глубинах зимой или (2) подледное распреснение за счет континентального стока. В связи
с этим макрозообентос сформирован эвритермальными и эврихалинными видами и характеризуется по-
ниженной биомассой. Маловероятно, что континентальные мелководья полуострова Русский Заворот
играют значимую роль как кормовые угодья для бентосных хищников, поскольку бедное по видовому
составу и биомассе сообщество L. balthica не формирует достаточной для морских птиц кормовой био-
массы. Сообщество L. balthica может быть использовано в качестве индикатора дальнейших климатиче-
ских изменений в акватории, поскольку можно предположить, что уменьшение толщины морского льда
улучшит условия обитания и приведет к увеличению размеров и биомассы мелководных моллюсков.
Ключевые слова: Limecola balthica, Арктика, биомасса, макробентосные сообщества, эстуарий
Nature Conservation Research. Заповедная наука 2019. 4(4)
... In the marine environment, a large number of species of mycromycetes has been found -inhabitants of land: water (Kopytina, 2020), benthic sediments (Bubnova et al., 2020), driftwood (Immaculatejeyasanta et al., 2012), on shells and internal organs of mollusks (Borzykh & Zvereva 2012Greco et al., 2017;Hudyakova et al., 2017), corals (Yarden, 2014;, sponges (Pivkin et al., 2006), algae (Gnavi et al., 2017) and other marine organisms (Raghukumar, 2012;Gebruk et al., 2019). Some terrestrial fungi cause diseases of hydrobionts, for instance, Aspergillus sydowii (Bainier & Sartory) Thom & Church caused epizooty of marine sea fans (Gorgonia ventalina Linnaeus, 1758 andG. ...
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Fungi are the most active biodeteriorators of natural and man-made materials. The article presents generalizations of the studies (2001-2019) of communities of microscopic fungi within biofilms on various substrates: shells of live Mytilus (Mytilus galloprovincialis, 670 specimens) and Ostreidae (Crassostrea gigas, 90 specimens), fragments of driftwood (over 7,000), stones (40), concrete of hydrotech-nical constructions along the shoreline (80) and wood between concrete blocks in constructions on the shores (80). The studies were carried out in Odessa Oblast, the coastal zone of Sevastopol and open area of the Black Sea. There were identified 123 species of micromycetes, belonging to 65 genera, 33 families, 21 orders, 10 classes, 4 divisions, 2 kingdoms: Fungi and Chromista (fungi-like organisms). The Chro-mista kingdom was represented by 1 species-Ostracoblabe implexa, on shells of C. gigas. The number of species of micromycetes on various substrates varied 23 (wood between concrete blocks of hydrotechnical constructions) to 74 (shells of M. galloprovincialis at the depths of 3 and 6 m). On all the substrates, the following species were found; Alternaria alternata, Botryotrichum murorum. The communities were found to contain pathogenic fungi Aspergillus fumigatus (shells of mollusks, stones, concrete), A. terreus (concrete), Fusarium oxysporum, Pseudallescheria boydii (shells of mollusks). The best representation was seen for the Pleosporales order-from 12.9% (shells of M. galloprovincialis, 0.3 m depth) to 33.3% (shells of C. gigas) of the species composition. Toxin-producing species of Microascales in mycological communities accounted for 1.6% (driftwood) to 40.0% (concrete), and were also observed on shells of Bivalvia-11.1-32.3%. Similarity of species composition of mycological communities according to Bray-Curtis coefficient varied 21.1% (driftwood and concrete, 10 shared species) to 72.7% (shells of M. galloprovincialis, the depths of 3 and 7 m and shells of C. gigas, 45 shared species). Using graphs of indices of mean taxonomic distinctness (AvTD, Δ+) and variation (Variation in Taxonomic Distinctness index, VarTD, Λ+), we determined deviations of taxonomic structure of the studied mycological communities from the level of mean expected values, calculated based on the list of species, taking into account their systematic positions. The lowest values of index Δ+ were determined for communities on shells of M. galloprovincialis, 0.3 m depth, driftwood, stones and concrete. These communities had uneven distribution of species according to higher taxonomic ranks and minimum number of the highest taxa: 4-6 classes, 1-2 divisions, Fungi kingdom. Disproportion in species composition with decrease in the number of the highest taxa occurred in extreme environmental conditions. Using index Λ+, we found that the most complex taxonomic structure of fungi communities has developed on concrete and shells of C. gigas. In mycological communities on those substrates, the number of species was low (25 and 46), but they belonged to 4-7 classes, 2-3 divisions, 1-2 kingdoms. To compare the structures of mycological communities that have developed in such substrates in biotopes sea, sea-land-air, land-air, we compiled a list of fungi based on the literature data, which, taking into account our data, comprised 445 species of 240 genera, 103 families, 51 orders, 15 classes, 5 divisions, 2 kingdoms. The analysis revealed that on substrates with similar chemical composition, in all the biotopes, the species of the same divisions dominated (genus and family may vary). Therefore, in the biotope land-of myxomycetes is needed in farms that cultivate industrial objects, recreation sites, various buildings for prevention of mycotoxin intoxication and infestation by mycodermatoses and other diseases caused by opportunistic and pathogenic fungi.
... This difference is mainly determined by the two mollusk species, Portlandia arctica and Cyrtodaria kurriana, with average biomasses of 62.5 and 14.2 g/m 2 , respectively. The latter species remained in Pechora Bay; in 2016, it was found in the shallow waters of its northwestern part at a depth of about 1 m [14]. The vanishing of two species from the community did not change the abundance of the other species. ...
... Average biomass of macrobenthos in the Pechora Sea ranges from 1.5 to 536 g wet weight per m 2 (Denisenko et al. 2003). The shallows of Pechora Bay are characterised by particularly low biomass (Gebruk et al. 2019;Denisenko et al. 2019b), whilst the north-western parts near the Novaya Zemlya and Vaygach Islands have the highest values of biomass of macrobenthic invertebrates in the Pechora Sea with largest contributions formed by bivalve molluscs Astarte borealis, Ciliatocardium ciliatum, Serripes groenlandicus, Nicania montagui and Macoma calcarea (Denisenko et al. 2019a;Gebruk et al. 2020). The presence of C. opilio and predation on benthic invertebrates may have an impact on the structure of these macrobenthic communities in the Pechora Sea, and may also go on to affect the availability of benthic feeding resources for seabirds (i.e. common eiders and other sea ducks) and marine mammals that forage on the benthos here including Atlantic walrus (Odobenus rosmarus; Gebruk et al. 2020) of the endangered Pechora Sea population (walrus listed as Vulnerable in the International Union for Conservation Red List, IUCN 2016). ...
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Expanding human activities alongside climate change, the introduction of invasive species and water contamination pose multiple threats to the unique marine ecosystems of the Pechora Sea in the Russian Arctic. Baseline data on biodiversity and responses to environmental change are urgently needed. Benthic decapod crustaceans are globally distributed and play an important role in fisheries, yet their roles in food webs are less understood. In this study, we used an integrated approach combining stomach content analysis and stable isotope analyses (δ¹³C and δ¹⁵N) to examine the trophic niches of three decapod species in the Pechora Sea including the invasive snow crab Chionoecetes opilio and two species of native decapods, the spider crab Hyas araneus and the hermit crab Pagurus pubescens. Stomach contents of 75 decapods were analysed (C. opilion = 23; H. araneusn = 9; P. pubescensn = 43), and 20 categories of prey items were identified with the most frequently occurring prey items being bivalve molluscs (Ciliatocardium ciliatum, Ennucula tenuis, Macoma calcarea), polychaetes, crustaceans and plant debris. Bayesian ellipse analyses of stable isotope signatures (n = 40) revealed that C. opilio displays an overlapping trophic niche with the two native decapods, providing direct evidence that the invader likely competes for food resources with both H. araneus and P. pubescens. As such, the presence of this invasive species could hold important consequences for trophic interactions, benthic ecosystem functioning and biodiversity. Microplastics were also found to be a likely stressor on this ecosystem, as 28% of all stomachs contained digested microplastics among other items. Long-term studies of benthic ecosystem structure and functioning are now needed to more fully understand the extent to which this new competitor may alter the future biodiversity of the Pechora Sea alongside the additional stressor of digested plastics.
... Most of the benthic surveys in the area were conducted on board large research vessels, and the upper depth limit of these studies was about 10 m, resulting in near-shore shallow waters remaining massively under-reported. This is a common problem specifically for Arctic marine nature reserves because the outermost limits of these reserves rarely approach this depth (Gebruk et al., 2019). Therefore, benthic foraging resources for Atlantic walrus in the Pechora Sea have not been comprehensively studied because some of the key feeding grounds, such as those between Vaigach and Matveev islands (Semenova et al., 2019), are located in shallow waters. ...
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• The Atlantic walrus, Odobenus rosmarus rosmarus , forms a herd of nearly 4,000 heads in the Pechora Sea (south‐eastern Barents Sea). The Near Threatened status of O. rosmarus rosmarus and the relative isolation of the Pechora Sea population, as well as the potential impacts of human activities in the area, make it important to characterize key habitats, including feeding grounds, in order to protect the species. • The aim of the present study was to integrate multiple sources of environmental and biological data collected by satellite telemetry, remotely operated vehicle (ROV), and benthic grab sampling to examine the distribution and diversity of benthic foraging resources used by walrus in the Pechora Sea. • Analysis of satellite telemetry data from seven males tagged on Vaigach Island helped to identify areas of high use by walruses near haulout sites on Matveev and Vaigach islands, and in between. Field data were collected from those feeding grounds in July 2016 using ROV video recordings and bottom grab sampling. Analysis of 19 grab stations revealed a heterogeneous macrobenthic community of 133 taxa with a mean biomass of 147.11 ± 7.35 g/m². Bivalve molluscs, particularly Astarte borealis , Astarte montagui , and Ciliatocardium ciliatum , dominated the overall macrobenthic biomass, making up two‐thirds of the total. • Analysis of 16 ROV video transects showed high occurrences of mobile benthic decapods (3.03 ± 2.74 ind./min) and provided the first direct evidence that areas actively used by walrus in the Pechora Sea overlap with the distribution of the non‐native omnivorous snow crab, Chionoecetes opilio . • Integrating multiple data sources provides an early foundation for the kinds of ecosystem‐based approaches needed to improve Pechora Sea resource management and to underpin Russia’s nascent marine spatial planning initiatives. Factors that need to be considered in marine spatial planning include impacts on benthic feeding grounds from offshore oil and gas development and the spread of the snow crab.
The results of hydrobiological studies during the growing season of 2020 are presented. Qualitative and quantitative indicators of macrozoobenthos as a food resource of lakes Ik and Saltaim-Tenis are studied. In the lake Ik 7 taxa of macrozoobenthos exclusively of the class insects (Insecta) were registered. In the zoobenthos of lake Saltaim-Tenis 9 taxa of three classes were noted: insects, oligochaetes (Oligochаeta), and roundworms (Nematoda). In a comparative analysis of the species similarity of the zoobenthos of the lake Ik from the lake Saltaim-Tenis, the Jaccard coefficient was 0,8, which indicates the complete correspondence of the species compositions of these lakes. Common to the lakes were species characteristic of mesoand eutrophic water bodies Ch. gr. plumosus, C. defectus, E. carbonaria, G.glaucus, P. choreus, P. ferrugineus, C. salinarius. The average seasonal number of zoobenthos of the lake Ik reached 747±47 ind./m2, Saltaim-Tenis was 67±4,6 ind./m2, which is 11 times less than in lake Ik. Biomass of zoobenthos of the lake Ik was characterized by high rates throughout the season and averaged 25,9±4,21 g/m2, Saltaim-Tenis averaged 2,62±0,2 g/m2, which is 9,8 times less than in lake Ik. The maximum abundance and biomass of zoobenthos in lake Ik, observed in spring. On the lake Saltaim-Tenis, the highest abundance was recorded in autumn, biomass — in summer. The minimum values of zoobenthos abundance on both lakes were noted in summer, biomass — in autumn. The ecological state of the lakes has been established. Trophic status of the lake Ik estimated from the summer biomass of zoobenthos corresponds to the β-eutrophic type, high productivity class, very high-feeding water body. The lake Saltaim-Tenis, according to the summer indicators of zoobenthos biomass, belongs to the medium-feeding water body. According to the trophic status, it belongs to the α-mesotrophic type of the moderate productivity class.
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Although benthic fauna in the Pechora Sea (SE Barents Sea) is generally well-studied, information on the bottom communities in the shallows near islands and the mainland is still sparse. Shallow marine areas in the Pechora Sea serve as important feeding grounds for numerous benthophagous fish, waterfowl and marine mammals, including the Atlantic walrus (Odobenus rosmarus rosmarus). To study the patterns of macrozoobenthic distribution in the shallows and evaluate the ecological state of the zoobenthic populations close to walrus haul-outs, sampling was performed in 2014 and 2016 around an archipelago in the Pechora Sea. In 2014, the average biomass, the Shannon's Diversity Index and the predominance of filter feeders in benthic communities were, in general, similar to the respective characteristics in neighboring deeper areas studied in the 1990s. In 2016, significant differences in species number and in biomass were recorded compared to 2014. An increase was observed in Atlantic boreo-Arctic species. Analysis of the trophic structure showed a slight decrease in the proportion of filter feeders and a significant increase in the proportion of subsurface deposit feeders. However, the Shannon's Diversity and Ecological Stress Indices indicated that the macrozoobenthos in the study area was in a state of equilibrium. Changes in the zoobenthos may result from several factors, such as an increase in water temperature, sediment re-deposition under wind-induced waves and the plowing of bottom sediments by walruses during their foraging.
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Population dynamics of common intertidal bivalves (Cerastoderma edule, Macoma balthica, Mya arenaria, My- tilus edulis) are strongly related to seawater temperatures. In northwestern European estuaries, series of mild winters followed by low bivalve recruit densities lead to small adult stocks. In this study, we examine temperature-induced effects on reproductive output (eggs m 22 ), onset of spawning (day of the year), and the juvenile instantaneous mortality rate (per day) of M. balthica. Data analysis was based on an extensive long-term data set (1973-2001) originating from the western Wadden Sea. Our results strongly suggest that rising seawater temperatures affect recruitment by a decrease in reproductive output and by spring advancement of bivalve spawning. Apparently, global warming upsets the evolved reproductive strategy of this marine bivalve to tune its reproduction to the most optimal environmental conditions for the first vulnerable life stages, most importantly the match/mismatch of time of spawning with that of the phytoplankton bloom and the settlement of juvenile shrimps on the tidal flats. It is hypothesized that the observed density-dependent mortality of juvenile bivalves may act via competition for food, a behavioral response of shrimp to low spat densities, or be the result of the response of age and size at metamor- phosis of marine bivalves to resource variability. It is to be expected that prolonged periods of lowered bivalve recruitment and stocks will lead to a reformulation of estuarine food webs and possibly a reduction of the resilience of the system to additional disturbances, such as the depletion and disturbance by shellfish fisheries.
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Extensive investigations on macrozoobenthic communities of the Pechora Sea (SE Barents Sea), carried out between 1991 and 1995, indicate that it is rich in terms of diversity, with a total of 712 taxa observed (505 identified to species level). Biomass distribution of zoobenthos varied greatly (2.6 to 1200 g m–2 wet wt). Average values recorded for the offshore areas are high for an Arctic environment, implying that the influence of the large Pechora River may extend far into the offshore area. In addition, intensive sedimentation of organic matter during the retreat of the highly productive ice-edge zone in the summer may also contribute to the observed high biomass. A method combining the abundance and biomass values of species was used to calculate an index approximating the production of each species. This index was used to distinguish the different community types in the area. In the study area, 13 benthic community types were identified, of which 2 main types covered most of the offshore areas. The concentration of total organic carbon (TOC) in the sediment was shown to have a strong influence on the diversity of the benthic communities, while both TOC and water depth affected the distribution of communities and the feeding mode of the dominant species. A community type consisting of surface deposit-feeders is the most widely distributed type in the area. Suspension feeders, however, dominate an extensive shallow offshore area. Boreal-Arctic species show a marked predomination (68.9%) in the whole Pechora Sea. The share of Arctic species is greater in the northern part influenced by cold water currents, while boreal species predominate in areas affected by warmer coastal waters. These observations indicate that the Pechora Sea functions as a transitional zone between boreal and Arctic biogeographic regions.
A description df species composition and structure of shallow zone benthic communities in the Baydara Bay (southwestern part of the Kara Sea) is given in the article. The depths from 0 to 3-5 m are inhabited by original fauna which is distinct from the one in deep waters. There were 19 species of macrobenthos found in the shallow zone and only 8 of them were also found deeper then 5 m. Characteristic species of the coastal zone are bivalvias Cyrtodaria curriana and Macoma baltica. Several methods of communities segregation: "Pianka" similiarity index, principle component analysis and comparision of sets of most abundant species lead to nearly the same results. A community with predominance of C. curriana and M. baltica inhabits the zone of mobile sands. C. curriana avoids lenitic areas where accumulation process prevails, polychaeta Spio filicornis and seaflea Monoculopsis longicoric are predominant there. Stations with intermediate environmental conditions also have intermediate species structure and sets of dominants. Analysis of species rank distribution shows that for the communities existing under severe environmental conditions the model of MacArthur provides the best approximation, while there are no theoretical model correctly describing species distribution of the C. curriana + M. baltica community; The best correspondence to the "geometrical rows" model was found for separated trophic guildes instead of the community as a whole.
One of the logical predictions for a future Arctic characterized by warmer waters and reduced sea-ice is that new taxa will expand or invade Arctic seafloor habitats. Specific predictions regarding where this will occur and which taxa are most likely to become established or excluded are lacking, however. We synthesize recent studies and conduct new analyses in the context of climate forecasts and a paleonto-logical perspective to make concrete predictions as to relevant mechanisms, regions, and functional traits contributing to future biodiversity changes. Historically, a warmer Arctic is more readily invaded or tran-sited by boreal taxa than it is during cold periods. Oceanography of an ice-free Arctic Ocean, combined with life-history traits of invading taxa and availability of suitable habitat, determine expansion success. It is difficult to generalize as to which taxonomic groups or locations are likely to experience expansion, however, since species-specific, and perhaps population-specific autecologies, will determine success or failure. Several examples of expansion into the Arctic have been noted, and along with the results from the relatively few Arctic biological time-series suggest inflow shelves (Barents and Chukchi Seas), as well as West Greenland and the western Kara Sea, are most likely locations for expansion. Apparent temperature thresholds were identified for characteristic Arctic and boreal benthic fauna suggesting strong potential for range constrictions of Arctic, and expansions of boreal, fauna in the near future. Increasing human activities in the region could speed introductions of boreal fauna and reduce the value of a planktonic dispersal stage. Finally, shelf regions are likely to experience a greater impact, and also one with greater potential consequences, than the deep Arctic basin. Future research strategies should focus on monitoring as well as compiling basic physiological and life-history information of Arctic and boreal taxa, and integrate that with projections of human activities and likely ecosystem consequences to facilitate development of management strategies now and in the future.
Most estuarine ecology textbooks have included the so-called Remane diagram which is derived from German studies in the Baltic Sea region during the early part of the 20th Century. The model shows how aquatic species diversity changes from freshwater to more marine areas. In essence it aims to show the relative proportions of each component of the fauna (freshwater, brackish and marine) and how these change along a salinity gradient. These combined components decrease in diversity with a progression from both the freshwater and marine ends of the spectrum, with the 5–7 salinity area being dominated by a small number of true brackish/estuarine species. The way in which the Remane diagram has been interpreted (and misinterpreted) and used (and misused) in the literature is discussed here. We primarily investigate whether the model needs to be modified to help provide an understanding of current biotic distribution patterns within estuaries and how these patterns might be influenced by climate change. Using global estuarine examples for a variety of taxa we discuss the appropriateness of the Remane model beyond the zoobenthos (on which the model was originally based) and provide a revised model that is more suited to estuaries worldwide. Comment is also provided on the way in which a more appropriate estuarine biodiversity model can influence future estuarine ecotone and ecocline studies.
Benthic studies in two seasonally ice-covered Arctic estuaries include description of the faunal composition, biodiversity, quantitative distribution, and biogeographic structure of the fauna. Water temperature and salinity variations, bottom relief, and sediment composition are important features influencing the zoobenthos of Pechora Bay and oh Bay. The inner parts of the bays are occupied by freshwater and brackish water fauna, while marine species occupy the mouths of the bays. Species diversity increases from the inner parts to the open sea, while the homogeneity of the community reflects the opposite tendency.