Marine benthos from Davis Station, Eastern Australia

1980 ◽  
Vol 31 (6) ◽  
pp. 829 ◽  
Author(s):  
DA Everitt ◽  
GCB Poore ◽  
J Pickard
Keyword(s):  
Sea Ice ◽  
Community Composition ◽  
Physical Environment ◽  
Species Level ◽  
Amphipod Species ◽  
Habitat Types ◽  
Marine Benthos ◽  
Eastern Australia ◽  
Deposit Feeding

Marine benthos from 24 nearshore sites in the vicinity of Davis station, eastern Antarctica, was sampled from the sea-ice. The sediments were poorly sorted and mainly of wind-blown origin. Thirty-two animal taxa were recognized and most crustaceans were identified to species level. Three habitat types were characterized by their community composition and physical environment: (1) species-rich areas with abundant macrophytes; (2) deep anoxic muddy basins with deposit-feeding species; and (3) poorly sorted sands with mainly motile fauna. Two amphipod species were recorded as new for eastern Antarctica.

scholarly journals Do the assemblages of benthic macroinvertebrates in nearshore waters of Western Australia vary among habitat types, zones and seasons?

2005 ◽  
Vol 85 (2) ◽  
pp. 217-232 ◽  
Author(s):  
M.D. Wildsmith ◽  
I.C. Potter ◽  
F.J. Valesini ◽  
M.E. Platell
Keyword(s):  
Species Composition ◽  
Benthic Macroinvertebrates ◽  
Habitat Type ◽  
Abundant Species ◽  
Subtidal Zone ◽  
Habitat Types ◽  
Environmental Characteristics ◽  
Deposit Feeding ◽  
Number Of Individuals

Benthic macroinvertebrates were sampled seasonally in the subtidal and upper and lower swash zones at two sites in each of six nearshore habitat types on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether sea grass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics (Valesini et al., 2003). The core samples yielded 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes, contributing ∼38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates at the most protected habitat type (1), i.e. 70 and 209·2 individuals 0·1 m−2, respectively, were far greater than in any other habitat type. Habitat type influenced species composition to a greater extent than either zone or season. Furthermore, the extents of the differences among the species compositions of the six habitat types statistically matched the extents of the differences among the values for the suite of enduring environmental characteristics that distinguished each of those habitat types. Overall, the species composition at habitat type 1 was the most distinct, containing five abundant species of polychaetes that were adapted to deposit-feeding in calm waters with high levels of organic material and which were rare in all other habitat types. In contrast, the fauna at the most exposed habitat type was characterized by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in turbulent waters. The zonal differences in faunal compositions among habitat types were greatest in the case of the subtidal zone. The faunal compositions differed among zones and seasons only at the most protected habitat type.

scholarly journals Amphipod (Crustacea, Amphipoda) Communities in the North-Western Part of the Black Sea

2016 ◽  
Vol 50 (5) ◽  
pp. 387-394
Author(s):  
S. A. Kudrenko
Keyword(s):  
Species Composition ◽  
Community Composition ◽  
Black Sea ◽  
The Black Sea ◽  
Published Data ◽  
Amphipod Species ◽  
Quantitative Parameters ◽  
The North ◽  
North Western

Abstract The data about the community composition, number and biomass of amphipods in three gulfs of the North-Western Black Sea are presented. The amphipod communities of the gulfs of Yahorlyk, Karkinit, and Tendra were studied and the species composition was compared with the previously published data. For each particular gulf, the list of amphipod species was composed. The quantitative parameters of the amphipod communities in the studied localities in different years were described.

2. The physical environment

2021 ◽  
pp. 14-38
Author(s):  
Klaus Dodds ◽  
Jamie Woodward
Keyword(s):  
Sea Ice ◽  
Physical Environment ◽  
Greenland Ice Sheet ◽  
The Arctic ◽  
Far North ◽  
Sea Ice Decline ◽  
Antarctic Continent ◽  
Polar Opposite ◽  
The Antarctic

‘The physical environment’ describes the Arctic as the polar opposite of the Antarctic continent as it is an ocean semi-enclosed by land. The rocks of the Arctic record key periods in Earth history. The Arctic environment has had an interesting path of evolution. Why is the Arctic cold today? The polar latitudes actually receive less solar energy than the rest of the Earth's surface. What is the key role of sea ice in the Arctic climate system? How does sea ice decline impact upon the Arctic Ocean? The Greenland ice sheet, high latitude glaciers, and the importance of permafrost in the far north are also important topics related to the physical environment.

A Parapatric Boundary between Ranidella signifera and R. riparia (Anura: Leptodactylidae) in South Australia

1982 ◽  
Vol 30 (1) ◽  
pp. 49 ◽  
Author(s):  
FJ Odendaal ◽  
CM Bull
Keyword(s):  
Competitive Advantage ◽  
Close Association ◽  
South Australia ◽  
Wide Distribution ◽  
Habitat Types ◽  
South Eastern ◽  
The North ◽  
Flinders Ranges ◽  
Eastern Australia ◽  
Overlap Area

Ranidella signifera has a wide distribution in south-eastern Australia; R. riparia is endemic to the Flin- ders Ranges in South Australia. The ranges of the two species are largely allopatric, but they contact and overlap in a zone about 10 km wide, in the southern Flinders Ranges. The nature of the creeks changes across this zone. Immediately to the south and east, where only R. signifera is found, the creeks are slow-flowing and heavily vegetated, with mud or sand substrates. To the north and west the creeks are swift-flowing, and have rocky substrates and little vegetation; only R. riparia is found in these. In the sympatric overlap zone creeks are heterogeneous, with both habitat types represented. The close association between species and creek habitat is lost in populations not immediately adjacent to the overlap zone. This implies that each species can survive in both creek habitats but that R. riparia has a competitive advantage in swift, rocky creeks and R, signifera has an advantage in slow, vegetated creeks. This prevents either species from expanding its distribution beyond the narrow overlap area.

scholarly journals Effects of Vertical Water Mass Segregation on Bacterial Community Structure in the Beaufort Sea

2019 ◽  
Vol 7 (10) ◽  
pp. 385
Author(s):  
Yunyun Fu ◽  
Richard B. Rivkin ◽  
Andrew S. Lang
Keyword(s):  
Bacterial Community ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Community Composition ◽  
Bacterial Communities ◽  
Water Mass ◽  
Beaufort Sea ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Mass Segregation

The Arctic Ocean is one of the least well-studied marine microbial ecosystems. Its low-temperature and low-salinity conditions are expected to result in distinct bacterial communities, in comparison to lower latitude oceans. However, this is an ocean currently in flux, with climate change exerting pronounced effects on sea-ice coverage and freshwater inputs. How such changes will affect this ecosystem are poorly constrained. In this study, we characterized the bacterial community compositions at different depths in both coastal, freshwater-influenced, and pelagic, sea-ice-covered locations in the Beaufort Sea in the western Canadian Arctic Ocean. The environmental factors controlling the bacterial community composition and diversity were investigated. Alphaproteobacteria dominated the bacterial communities in samples from all depths and stations. The Pelagibacterales and Rhodobacterales groups were the predominant taxonomic representatives within the Alphaproteobacteria. Bacterial communities in coastal and offshore samples differed significantly, and vertical water mass segregation was the controlling factor of community composition among the offshore samples, regardless of the taxonomic level considered. These data provide an important baseline view of the bacterial community in this ocean system that will be of value for future studies investigating possible changes in the Arctic Ocean in response to global change and/or anthropogenic disturbance.

scholarly journals Contrasting effects of mangroves and armoured shorelines on fish assemblages in tropical estuarine seascapes

2019 ◽  
Vol 76 (4) ◽  
pp. 1052-1061 ◽  
Author(s):  
Christopher J Henderson ◽  
Ben L Gilby ◽  
Thomas A Schlacher ◽  
Rod M Connolly ◽  
Marcus Sheaves ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Urban Expansion ◽  
Ecological Impacts ◽  
Spatial Context ◽  
Fish Diversity ◽  
Mangrove Forests ◽  
Habitat Types ◽  
Tropical Estuarine ◽  
Eastern Australia ◽  
Close Proximity

Abstract Coastal seascapes are composed of a diversity of habitats that are linked in space and time by the movement of organisms. The context and configuration of coastal ecosystems shapes many important properties of animal assemblages, but potential seascape effects of natural and artificial habitats on nearby habitats are typically considered in isolation. We test whether, and how, the seascape context of natural and urban habitats modified fish assemblages across estuaries. Fish were sampled with underwater videos in five habitat types (mangroves, rock bars, log snags, unvegetated sediments, armoured shorelines) in 17 estuaries in eastern Australia. Different habitats supported distinct fish assemblages, but the spatial context of mangroves and armoured shorelines had pervasive ecological effects that extended across entire estuaries. In most estuarine habitats, fish diversity and abundance was greatest when they were in close proximity of mangroves, and decreased due to the proximity of armoured shorelines. Many cities are centred on estuaries, and urban expansion is often associated with the fragmentation of mangrove forests. Our findings emphasize that these transformations of urban estuarine landscapes are likely to propagate to broader ecological impacts detectable in multiple habitats beyond mangrove forests.

scholarly journals Observed climate change in Australian marine and freshwater environments

2011 ◽  
Vol 62 (9) ◽  
pp. 984 ◽  
Author(s):  
Janice M. Lough ◽  
Alistair J. Hobday
Keyword(s):  
Climate Change ◽  
Physical Environment ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Hydrological Regime ◽  
Freshwater Ecosystems ◽  
Eastern Australia ◽  
Average Rainfall ◽  
Terrestrial Environments ◽  
Recent Trends

The consequences of human activities increasing concentrations of atmospheric greenhouse gases are already being felt in marine and terrestrial environments. More energy has been trapped in the global climate system, resulting in warming of land and sea temperatures. About 30% of the extra atmospheric carbon dioxide has been absorbed by the oceans, increasing their acidity. Thermal expansion and some melting of land-based ice have caused sea level to rise. Significant climate changes have now been observed across Australia and its coastal seas. The clearest signal is the warming of air and sea temperatures and the rates of warming have accelerated since the mid-20th century. Ocean warming has been higher than the global average around Australia, especially off south-eastern Australia. Changes in Australia’s hydrological regime are more difficult to differentiate from the high natural inter-annual variability. Recent trends towards drier winters in south-western Western Australia and part of southern Australia appear, however, to be largely attributable to human-induced climate change. Even without significant changes in average rainfall, warmer temperatures increase evaporative losses, enhance the intensity of recent droughts and reduce river flows. Sustained and coordinated monitoring of the physical environment, especially lacking for Australia’s freshwater ecosystems, is important to assess the magnitude and biological consequences of ongoing changes.

The Occurrence of Scalariform Perforation Plates and Helical Vessel Wall Thickenings in Wood of Myrtaceae

IAWA Journal ◽  
1984 ◽  
Vol 5 (3) ◽  
pp. 197-215 ◽  
Author(s):  
Rudolf Schmid ◽  
Pieter Baas
Keyword(s):  
Vessel Wall ◽  
Selective Pressure ◽  
Diagnostic Value ◽  
Adaptive Significance ◽  
Species Level ◽  
Tropical Species ◽  
Habitat Types ◽  
Vessel Elements ◽  
Perforation Plates ◽  
Helical Thickenings

The occurrence of multiple perforation plates and helical wall thickenings in vessel elements of 144 species (plus 12 varieties and 2 hybrids) in 53 genera of Myrtaceae was extensively explored. Scalariform perforation plates occur in 40 species (plus 1 hybrid), in Luma, Myrceugenia, Myrteola, Ugni, and in the monotypic Myrtastrum rujo-punctatum, Neomyrtus pedunculata, and Tepualia stipularis. Ugni candollei also has foraminate (i.e., sieve-like) perforation plates. Helical wall thickenings occur in 33 species (plus 1 hybrid), in Acmena, Austromyrtus, Myrceugenia, Myrcia, Myrcianthes Psidium, Xanthomyrtus, and in Myrtus communis. Most of these records are new. The speeies with exclusively scalariform perforation plates (in Luma, Myrteola, Neomyrtus, and Ugni) are from cool mesic habitats; those with mixed simple and multiple perforation plates are also largely cool mesic but show a somewhat greater diversity of habitats. Myrtaceae with exclusively simple perforation plates predominate in all habitat types. Helical wall thickenings occur sporadically throughout the distributional range ofthe family. However, tropical species tend to have weaker helical thickenings than the subtropical and temperate species exhibiting them. The possible functional significance of these ecological tendeneies is discussed. It is hypothesised that multiple perforation plates were retained in some cool mesic Myrtaceae because of a lack of strong selective pressure to eliminate them from this type of environment, rather than that they were retained because of adaptive significance in trapping embolisms. The systematic and diagnostic value of multiple perforation plates and helical wall thickenings is also discussed. Scalariform plates are largely confined to related genera in Myrtoideae; Tepualia is the only representative from Leptospermoideae. Helical wall thickenings are only of limited diagnostic and systematic value above the species level.

Species diversity and genetic differentiation of stygofauna (Syncarida:Bathynellacea) across an alluvial aquifer in north-eastern Australia

2012 ◽  
Vol 60 (3) ◽  
pp. 152 ◽  
Author(s):  
B. D. Cook ◽  
K. M. Abrams ◽  
J. Marshall ◽  
C. N. Perna ◽  
S. Choy ◽  
...  
Keyword(s):  
Species Diversity ◽  
Phylogenetic Analyses ◽  
Molecular Data ◽  
Alluvial Aquifer ◽  
Species Level ◽  
Coi Gene ◽  
Generic Level ◽  
Alluvial Aquifers ◽  
Eastern Australia ◽  
North Eastern

Recent research suggests that alluvial aquifers in southern and eastern Australia may contain a diverse subterranean aquatic fauna (i.e. stygofauna). However, to date only a limited number of alluvial aquifers have been studied and little molecular data are available to assess species-level diversity and spatial patterns of genetic variation within stygofaunal species. In this paper, we present the initial results of a stygofaunal survey of the Burdekin River alluvial aquifer in Queensland, extending the northern range of alluvial aquifers along the east coast of Australia that have been investigated. The survey resulted in the collection of bathynellid stygofauna (Syncarida: Bathynellacea) and genetic analyses were conducted to determine species level diversity using the mitochondrial cytochrome oxidase subunit I (COI) gene. We further investigated the phylogenetic relationships of the species with bathynellids from western and southern Australia to assess the generic status of species. Four highly divergent COI lineages within the Parabathynellidae and one lineage within the Bathynellidae were found. These lineages did not group within any described genera, and phylogenetic analyses indicated that both local radiations and the retention of a lineage that was more apical in the genealogy account for the diversity within the Parabathynellidae in the Burdekin River alluvial aquifer. Most COI lineages were sampled from only a single bore, although one taxon within the Parabathynellidae was found to be more widespread in the aquifer. Haplotypes within this taxon were not shared among bores (ΦST = 0.603, P < 0.001). Overall, the high species diversity for bathynellaceans from an alluvial aquifer reported here, and surveys of bathynellaceans in several other alluvial systems in south-eastern Australia, suggests that groundwater ecosystems of eastern Australia may contain high stygofaunal diversity by Australian and world standards, particularly at the generic level for parabathynellids.

Sign in / Sign up

Export Citation Format

Share Document