Sea urchins, sea stars and brittle stars from Terra Nova Bay (Ross Sea, Antarctica)

Although echinoderms constitute some of the most conspicuous taxa of the Antarctic benthic communities, the echinoderm fauna of Terra Nova has not been described yet. The present study provides the first species list of echinoids, ophiuroids and asteroids from Terra Nova Bay (30–500 m depth) and describes the depth distribution of these species. Preliminary observations of the summer reproductive condition of some of the species are also included.     

Taxonomy of estuarine invertebrates in Australia

An Australian estuary is primarily a marine-dominated environment, subjected to major salinity changes only after heavy rains and during flood conditions. In southeastern Australia estuarine biota are similar to those in shallow coastal bays and some of the coastal lagoons, and most taxonomic studies on estuarine fauna have occurred in this region. Several major surveys of estuarine and coastal bays have been undertaken in Australia during the past three decades and these surveys have largely provided the material for taxonomic studies of the major groups of macrobenthos. All these studies have revealed a diverse and abundant benthic macrobenthos. The composition of estuarine invertebrate fauna is compared with open exposed coasts, including fauna found in soft strata and on hard strata. Australia has a limited specialized estuarine biota much of which is restricted to particular habitats, and a highly diverse marine community which thrives in the sheltered protected waters of estuaries and the associated soft sediments. Currently, interactive computer-based keys are being developed which should greatly assist the student and the benthic ecologist to identify the fauna and prevent potential loss of data. Some aspects of the current debate of the level of taxonomic resolution required to answer various ecological questions are discussed. Finally, some comments are suggested as to future directions in which taxonomists and estuarine ecologists should proceed in order to be able to detect changes or losses of estuarine biodiversity and the loss of the associated biological information which may be critical in understanding the functioning of the estuarine ecosystem.     

How rich is the deep-sea Antarctic benthic hydroid fauna?

The bathymetric distribution of the 155 known species of Antarctic benthic hydroids has been studied with the aim of determining bathymetric groups and estimating the richness of the deep-sea Antarctic benthic hydroid fauna. Six bathymetric groups could be recognized on the basis of vertical zonation patterns. Most species have wide bathymetric ranges, but must nevertheless be considered shelf species. Although 62 species of benthic hydroids have been found in the Antarctic deep-sea, only 10 are strict inhabitants of that area. An inverse relative dominance between anthoathecate and leptothecate hydroids has been observed, with the former being more frequent in shallow waters.     

Benthic indices and ecological quality of shallow Algeria fine sand community

This study applies six macrozoobenthos-based biotic indices in the shallow coastal waters along the Algerian coast (southern Mediterranean Sea) to establish a reference situation for future use. These shallow fine sand communities were sampled in seven bays along the Algerian coast during the 1980s and the beginning of the 1990s. For the first time, some of the benthic indices used nowadays in Europe for the implementation of the WFD and/or in North America for the Clean Water Act were used to analyze the data collected twenty years ago in order to assess the biological quality status of the Algerian shallow fine sand communities and to provide ecological classifications for the fine sand community along the Algerian coast. The faunal composition showed that the fine sand communities belonged to a Well-Calibrated Fine Sand (WCFS) biocenosis characterized by high species richness and high H′ Shannon-Weaver diversity, with moderate abundance levels only. In the bays of Fetzara, Jijel, Bejaia, Bou Ismail and Arzew (though not in bays of Algiers and Oran), H′ is >4.5, which implies highly diversified communities. The results of the six benthic indices (H′, AMBI, M-AMBI, BENTIX, BOPA and ITI) suggest that good and high quality status assessments are prevalent in all seven bays for the benthic shallow sand communities along the Algerian coast. Nevertheless, the effect of pollution was observed at a small number of sites in the Arzew, Oran and Algiers bays. For example, in Algiers Bay, an east-west quality gradient revealed the effect of organic matter input.     

Filling biodiversity gaps: benthic hydroids from the Bellingshausen Sea (Antarctica)

The Bellingshausen Sea constitutes the third largest sea in the Southern Ocean, though it is widely recognized as one of the less-studied Antarctic areas. To reduce this lack of knowledge, a survey to study the biodiversity of its marine benthic communities was carried out during the Bentart 2003 and Bentart 2006 Spanish Antarctic expeditions. The study of the hydroid collection has provided 27 species, belonging to ten families and 15 genera. Twenty-one out of the 27 species constitute new records for the Bellingshausen Sea, raising the total number of known species to 37, as also do nine out of the 15 genera. Candelabrum penola, Lafoea annulata, and Staurotheca juncea are recorded for the second time. Most species belong to Leptothecata. Sertulariidae with 13 species (48%) is by far the most speciose family, and Symplectoscyphus with seven species (26%), including S. bellingshauseni sp. nov. and S. hesperides sp. nov., the most diverse genus. Considering the whole benthic hydroid fauna of the Bellingshausen Sea, 18 species (69%) are endemic to Antarctic waters, either with a circum-Antarctic (12 species, 46%) or West Antarctic (6 species, 23%) distribution, 23 (88%) are restricted to Antarctic or Antarctic/sub-Antarctic waters, and only three species have a wider distribution. Bellingshausen Sea hydroid fauna is composed of a relatively high diversity of typical representatives of the Antarctic benthic hydroid fauna, though with a surprisingly low representation of some of the most diverse and widespread Antarctic genera (Oswaldella and Schizotricha), what could be related to the fact that its shelf-inhabiting hydroid fauna remains practically unknown.     

Diversity and distribution patterns in high southern latitude sponges

Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ～43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.     

Detecting glacial refugia in the Southern Ocean

Throughout the Quaternary, the continental-based Antarctic ice sheets expanded and contracted repeatedly. Evidence suggests that during glacial maxima, grounded ice eliminated most benthic (bottom-dwelling) fauna across the Antarctic continental shelf. However, paleontological and molecular evidence indicates most extant Antarctica benthic taxa have persisted in situ throughout the Quaternary. Where and how the Antarctic benthic fauna survived throughout repeated glacial maxima remain mostly hypothesised. If understood, this would provide valuable insights into the ecology and evolution of Southern Ocean biota over geological timescales. Here we synthesised and appraised recent studies and presented an approach to demonstrate how genetic data can be effective in identifying where and how Antarctic benthic fauna survived glacial periods. We first examined the geological and ecological evidence for how glacial periods influenced past species demography in order to provide testable frameworks for future studies. We outlined past ice-free areas from Antarctic ice sheet reconstructions that could serve as glacial refugia and discussed how benthic fauna with pelagic or non-pelagic dispersal strategies moved into and out of glacial refugia. We also reviewed current molecular studies and collated proposed locations of Southern Ocean glacial refugia on the continental shelf around Antarctica, in the deep sea, and around sub-Antarctic islands. Interestingly, the proposed glacial refugia based on molecular data generally do not correspond to the ice-free areas identified by Antarctic ice sheet reconstructions. The potential biases in sampling and in the choice of molecular markers in current literature are discussed, along with the future directions for employing testable frameworks and genomic methods in Southern Ocean molecular studies. Continued data syntheses will elucidate greater understanding of where and how Southern Ocean benthic fauna persisted throughout glacial periods and provide insights into their resilience against climate changes in the future.     

Impacts of introduced brown and rainbow trout on benthic invertebrate communities in shallow New Zealand lakes

1. Brown and rainbow trout have been introduced to many inland waters in New Zealand, but research on the impacts on native communities has focused mainly on streams. The purpose of this study was to compare the benthic communities of trout and troutless lakes. Based on previous studies in North America and Europe, we predicted that the benthic biomass, and especially the abundance of large invertebrates, would be lower in lakes with trout as compared to those without. We surveyed the invertebrate fauna of 43 shallow, high‐elevation lakes (26 with and 17 without trout) in four geographic clusters on the central South Island and then conducted a detailed quantitative study of invertebrate biomass and community structure in 12 of these lakes. 2. Benthic community composition and diversity of lakes with and without trout were nearly identical and biomass was as high or higher in the lakes with as without trout. There was no evidence that trout have caused local extinctions of benthic invertebrates. Although the proportional abundance of large‐bodied aquatic was slightly lower in lakes with than without trout, the abundance of several groups of large‐bodied benthic taxa (dragonflies, caddisflies and water bugs) did not differ. 3. Our findings are in contrast to those in North American and Europe where trout introductions into previously troutless lakes have led to declines in the abundance of benthic invertebrates, especially large‐bodied taxa. We propose that the modest effects of trout in New Zealand could be explained by (i) the high areal extent of submergent vegetation that acts as a benthic refuge, (ii) low intensity of trout predation on benthic communities and/or (iii) characteristics of the benthic invertebrates that make them relatively invulnerable to fish predation. 4. Regardless of the relative importance of these hypotheses, our results emphasise that the same invertebrates occurred in all of the lakes, regardless of size, elevation and presence of trout, suggesting habitat generalists dominate the benthic fauna in shallow New Zealand lakes.     

Spatio-temporal patterns of eukaryotic biodiversity in shallow hard-bottom communities from the West Antarctic Peninsula revealed by DNA metabarcoding

Aim

We studied molecular eukaryotic biodiversity patterns in shallow hard-bottom Antarctic benthic communities using community DNA metabarcoding. Polar ecosystems are extremely exposed to climate change, and benthic macroinvertebrate communities have demonstrated rapid response to a range of natural and anthropogenic pressures. However, these rich and diverse ecosystems are poorly studied, revealing how little is known about the biodiversity of the Antarctic benthos associated with hard-bottom habitats.

Location

West Antarctic Peninsula and South Shetland Islands.

Methods

Using data collected in seven localities along the western Antarctic Peninsula, we calculated spatial patterns of alpha and beta diversities. Furthermore, we analysed temporal changes in benthic composition in one location (Deception Island) over 3 years. We calculated the temporal alpha and beta diversities to reveal changes in this community over time.

Results

We obtained a final list of 2057 molecular operational taxonomic units. We found significant differences in benthic community composition between localities and among years. Our dataset revealed a total of 10 different kingdom-level lineages and 34 different phyla in the samples. The most diverse phylum was Arthropoda, followed by Bacillariophyta, and Annelida, while the highest relative read abundances belonged to Annelida, Porifera and Echinodermata. Benthic community compositions changed between 2016 and 2018 in Deception Island, and decreasing species richness was the main component of temporal beta diversity.

Main Conclusions

Direct sampling methods are required for monitoring these complex communities. Informative biodiversity patterns can be retrieved even though most of the benthic biodiversity found in Antarctic habitats is yet to be taxonomically described and barcoded. Hard-bottom assemblages exhibit high spatial variability and heterogeneity, not related to depth, which represent a huge challenge for large-scale studies in the Southern Ocean. Local patchiness and structure within these communities are probably a consequence of a combination of several biotic and abiotic factors (i.e. ice disturbance, food supply and competition).     

The distribution and abundance of soft-sediment macrobenthos around Casey Station, East Antarctica

Grab samples of shallow (5–35 m) marine benthic sediments and epi- and infaunal assemblages were taken from nearshore regions around Casey Station, Windmill Islands, East Antarctica. A hierarchical, spatially nested sampling design was used with locations (kilometres apart), sites (hundreds of metres apart) and plots (tens of metres). Two potentially impacted, polluted locations (adjacent to a sewage outfall and an old garbage tip) were compared with two control locations in an asymmetrical design. Significant differences in assemblages were found between locations and between sites within locations. Significant differences in the abundances of taxa at several taxonomic levels (species, family, order, phylum) were found at all three spatial scales. Significant differences were also detected between the polluted and control locations. Compared with other Antarctic locations, the assemblages were dominated by crustaceans (90–97% of individuals) and there was a paucity of polychaete fauna at the locations sampled. Accepted: 3 June 2000     

Das phylogenetische System der Tanaidacea und die Frage nach Alter and Herkunft der Crustaceenfauna des antarktischen Festlandsockels1,2

The phylogenetic system of the Tanaidacea and the question of age and origin of the crustacean fauna on the Antarctic shelf The final breakup of Gondwanaland during the Tertiary not only played an important role in establishing modern climates and oceanic currents but also had a tremendous influence on the composition of the Recent crustacean fauna. Analysis of the fossil record of the Tanaidacea shows that all Recent families had evolved before the Eocene. They all, therefore, had the chance to colonize the Antarctic shelf area. However, the tanaidacean fauna of this region is represented exclusively by phylogenetically young taxa. The species composition is atypical and does not correspond to those of other zoogeographic regions. Surprisingly, in the West Antarctic there occur some phylogenetic older taxa which are not recorded from the East Antarctic. In general, the species composition of the East Antarctic tanaidacean fauna is more like that of the deep sea while that of the West Antarctic is characterized by additional “littoral elements”. For the interpretation of recognized distribution patterns are most important geological events and the resulting effects on the changes in the world climates, e. g. it is commonly excepted that there is a continuous decrease of the surface water temperature since the paleocene. Deduced from foraminiferan data, it can be assumed that almost the entire Antarctic tanaidacean fauna was extinguished during the first dramatic drop of temperature. Cold-stenothermic eurybathic species then have colonized the Antarctic shelf. After the phase of maximal glaciation in the Pliozene the fauna of the West Antarctic was finally modified by Magellanian elements, which in some cases have to be accepted as phylogenetic old forms. Other available information on Crustacea, especially for Cirripedia, Ostracoda, Decapoda, and Isopoda support this interpretation. Therefore, it may be assumed that the Recent Antarctic crustacean fauna was established mainly about 38 m. y. ago. Practically no primitiv forms exist in this region, i. e. there are no relict species. On the contrary, we have to suggest that an important part of the fauna is represented by apomorphic species which have reached the Antarctic shelf from the deep sea. Polar emergence is a more likely hypothesis at the moment than tropical submergence. However, the final elucidation of this question can be given only after detailed phylogenetic analysis of the fauna of the adjacent deep sea basins.     

Bryozoans of the Weddell Sea continental shelf,slope and abyss: did marine life colonize the Antarctic shelf from deep water,outlying islands or in situ refugia following glaciations?

Aim At the height of glaciations such as the Last Glacial Maximum (LGM), benthic life on polar continental shelves was bulldozed off nearly all of the Antarctic shelf by grounded ice sheets. The origins of the current shelf benthos have become a subject of considerable debate. There are several possible sources for the current Antarctic shelf fauna, the first of which is the continental slope and deep sea of the Southern Ocean. The high levels of reported eurybathy for many Antarctic species are taken as evidence supporting this. A second possible source for colonists is the southern margins of other continents. Finally, shelves could have been recolonized from refugia on the continental shelves or slopes around Antarctica. The current study investigates whether the patchily rich and abundant biota that now occurs on the Antarctic continental shelf recolonized from refugia in situ or elsewhere. Location Weddell Sea, Antarctica. Methods We examined bryozoan samples of the BENDEX, ANDEEP III and SYSTCO expeditions, as well as the literature. Using similarity matrices (Sørensen coefficient), we assessed similarities of benthos sampled from around Antarctica. By assessing numbers of species shared between differing depths and adjacent shelf areas, we evaluated the origins of cheilostome bryozoan communities. Results Bryozoans decreased from 28, 6.5 and 0.3 colonies per trawl, and 0.16, 0.046 and 0.0026 colonies per cm² of hard surface from shelf to slope to abyssal depths. We found little and no support for recolonization of the Weddell Sea shelf by bryozoans from the adjacent slope and abyss, in the scenario of LGM faunal wipe‐out. The Weddell Sea shelf bryozoan fauna was considerably more similar to those on other Antarctic shelves than to that of the adjacent (Weddell Sea) continental slope. The known bryozoan fauna of the Weddell Sea shelf is not a subset of the Weddell Sea slope or abyssal faunas. Main conclusions We consider that the composition of the current Weddell Sea bryozoan fauna is most easily explained by in situ survival. Thus we consider that at least some of the Weddell Sea fauna persisted throughout the LGM, although not necessarily at the same locations throughout, to recolonize the large area currently occupied.     

The marine macrobenthic communities of Wallis and Smiths Lakes,New South Wales

The shallow macrobenthic communities of Wallis and Smiths Lakes on the central N.S. W. coast have been studied by replicate grab samples. Wallis Lake is a coastal marine lagoon constantly open to the sea, whereas Smiths Lake, also a coastal lagoon, is periodically closed to the sea for several months at a time. The benthic communities were described using indices of dominance and diversity. Between site communities were compared using MULTBET and a GOWER ordination. Generally, sites in Wallis Lake had a more diverse fauna than those in Smiths Lake. Weed beds supported more species and individuals than sandy substrates. The benthic fauna of these two lakes is compared with other coastal rivers and lagoons which have been studied in temperate eastern Australia.     

Hydroid assemblages from the Bellingshausen Sea (Antarctica): environmental factors behind their spatial distribution

Although scientific knowledge about the biodiversity of Antarctic benthic hydrozoans has considerably increased in recent years, little is known about their spatial distribution and underpinning factors. Trying to contribute to filling this gap, benthic hydroid spatial distribution in the Bellingshausen Sea (Southern Ocean) was studied. Samples were collected at 32 stations at depths between 86 and 3,304 m during Spanish Antarctic expeditions in 2003 and 2006. Sediments and bottom water properties were analyzed using an USNEL-type box corer and a Neil Brown Instrument System Mark III CTD, respectively. Forty species were reported (Acryptolaria sp., Stegopoma plicatile, Staurotheca dichotoma having the highest percentages of occurrence), representing ca. 19 % of the species richness of the known benthic hydroid fauna of the Southern Ocean. Three well-defined assemblages (shallow, deep and transitional) were established based on significant differences in species occurrence. Benthic hydroid spatial distribution in the Bellingshausen Sea seems to be controlled mainly by depth and substrate (most hydrozoan species are epibiotic), by species dispersal abilities and by species resilience to changing hydrodynamic conditions. The level of species richness found in the present study, compared with other Antarctic areas, gives support to arguments stated by authors against the idea that the Bellingshausen Sea is “a benthos desert” controlled by oligotrophic conditions and intense iceberg traffic.     

On the origin of Antarctic marine benthic community structure

Environmental conditions fostering marine communities around Antarctica differ fundamentally from those in the rest of the world's oceans, particularly in terms of pronounced climatic fluctuations and extreme cold. Here, we argue that the rarity of pelagic larval stages in Antarctic marine benthic invertebrate species is a consequence of evolutionary temperature adaptation and that this has greatly contributed to the current structure of the Antarctic benthic community. In arguing this position, we challenge the likelihood of previously suggested survival strategies of benthic communities on the Antarctic continental shelf and slope during Cenozoic glacial periods. By integrating evidence from marine geology and geophysics, we suggest that the Antarctic continental shelf and slope were both unfavourable environments for benthic communities during glacial periods and that community survival was only possible in the deep sea or in shelters on the continental shelf as a result of the diachronism in maximum ice extent.     

From spring sources to springbrook: Changes in environmental characteristics and benthic fauna

Spatial patterns in macroinvertebrate communities and some abiotic factors were examined in three rheocrene springs and their springbrooks (Kraków-Cz?stochowa Upland, southern Poland). The mean discharge of particular springs ranged from 5 to 11 L s^?1, and its annual fluctuations were small. Water temperature was very stable at all sampling sites. In the eucrenon the number of benthic taxa was the smallest (9–14 determined to the family level), but the densities were the highest (approx. 14000 ind. m^?2). The biggest changes in macroinvertebrate composition were observed in the modified hypocrenon, which is an artificial pond. The lowest number of taxa were found in a natural, short springbrook with a nondiversified bottom substrate. The density of crenophilic taxa (Drusus trifidus, Dugesia gonocephala, Elmidae) diminished along the springbrooks, while the opposite trend was observed for ubiquitous taxa (some Oligochaeta, Asellus aquaticus and Chironomidae). Even in a very short natural springbrook (30 m), Drusus trifidus, the only species of Trichoptera found in the springs discussed here, goes through the entire development cycle. The strongest influence of a big river was observed at the outflow of one of the natural springbrooks, where the highest number of riverine oligochaete species were found. The benthic fauna of the springs studied here differed from that found in other springs in this area — the absence of the typical crenophilic species Bithynella austriaca (Gastropoda) and the presence of Gianus aquedulcis (Oligochaeta) may indicate the autonomy of the spring fauna in the Mstów area, possibly resulting from the postglacial geomorphological formation of this region or differences in habitat conditions.     

Key stages in the evolution of the Antarctic marine fauna

We are beginning to appreciate that the origin of the modern Antarctic marine fauna is related to a series of key events throughout the Cenozoic era. In the first of these, the mass extinction at the Cretaceous–Palaeogene boundary (66 Ma) reset the evolutionary stage and led to a major radiation of modern taxa in the benthic realm. Although this took place in a greenhouse world, there is evidence to suggest that the radiation was tempered by the seasonality of primary productivity, and this may be a time‐invariant feature of the polar regions. Although there could well have been a single, abrupt extinction event at c. 34 Ma, there is also evidence to suggest a phased extinction of various taxa over a period of millions of years. Important new molecular phylogenetic data are indicating that a wide variety of both benthic and pelagic taxa radiated shortly after a second major phase of cooling at c. 14 Ma. Such a phenomenon is linked to a series of major palaeoceanographic changes, which in turn led to a proliferation of diatom‐based ecosystems. Although the modern benthic marine fauna can be traced back some 45–50 Myr, a substantial component of the modern pelagic one may be less than 14 Myr old. The latter is also characterized by assemblages of high abundance but comparatively low species richness and evenness. A distinctive signature of low diversity but high dominance within Antarctic marine assemblages was maintained by the interplay between temperature and primary productivity throughout the Cenozoic.     

Diversity,abundance and composition in macrofaunal molluscs from the Ross Sea (Antarctica): results of fine-mesh sampling along a latitudinal gradient

The Latitudinal Gradient Program (2002–2011) aimed at understanding the marine and terrestrial ecosystems existing along the Victoria Land coast (Ross Sea), an area characterized by strong latitudinal clines in environmental factors. During the program’s voyage of the Italian RV “Italica” in 2004, a fine-mesh towed gear, the “Rauschert dredge”, was deployed for the first time at 18 stations in four latitudinal distinct shelf areas between ~71°S and ~74°S. The collected samples contained undescribed species and new records for the Ross Sea from a variety of different marine taxa. Here, we describe the molluscan fauna and investigate evidences for latitudinal effects on molluscan diversity, abundance and assemblage composition. No significant latitudinal trends were detected: while diversity did not vary significantly with latitude, species richness showed an apparent but non-significant decrease with increasing latitude. Beta-diversity was found to be high both within and between latitudinally distinct shelf areas. A large fraction (~20 %) of the collected molluscs corresponded to new species records for the Ross Sea or undescribed species. Rarity in Antarctic molluscan occurrences was confirmed, with singletons (i.e. species represented by only a single individual) accounting for a 22 % and uniques (i.e. species occurring in one sample only) for a 43.5 % of the total presence. Our study of the smaller macrofaunal benthic fraction showed that Antarctic marine research still has far to go to have robust reference baselines to measure possible changes in benthic communities, even in the case of the assumed well-known, well-sampled and well-studied group of Ross Sea shelf molluscs. We advocate the use of fine-mesh trawling gears for routine sampling activities in future Antarctic expeditions to assess the full marine biodiversity.     

Seasonal and spatial variations in the zooplankton community of an Eastern Antarctic coastal location

Summary The zooplankton community of a shallow coastal area in Eastern Antarctica was found to be one of low species diversity dominated by Copepoda. It was comprised of the more common Antarctic oceanic copepod species, medusae, molluscs, euphausiids, several copepod species associated with the ice-water interface and, in summer, benthic fauna larvae. Most species of copepods displayed a marked seasonality in abundance with peak numbers between March and May. It is proposed that several factors, including phytoplankton seasonality contribute to the zooplankton species composition, zooplankton seasonality, and to the temporal differences in the period of maximum abundance between copepod species. Annual vertical migratory behaviour in conjunction with the circulation of Prydz Bay are important determining factors for those species which can be considered as oceanic; Calanoides acutus, Calanus propinquus, Ctenocalanus citer, Metridia gerlachei, Oithona similis and Oncaea curvata. However, for copepod species which can be classified as inshore residents, such as Stephos longipes, Paralabidocera antarctica and Drepanopus bispinosus, it is their association with the ice water interface that determines their seasonal appearance and abundance. Some differences were established between the zooplankton community of the Vestfold Hills and that of other Antarctic coastal regions. This may be attributed, in part, to the extensive shallow areas of the Vestfold Hills coastal region. Spatial distribution of the zooplankton with depth and between sites was investigated and found to be essentially homogenous. When differences were established, in the majority of cases all species present, all age classes and both sexes contributed to the differences.