scholarly journals Do Antarctic benthic invertebrates show an extended level of eurybathy?

1996 ◽  
Vol 8 (1) ◽  
pp. 3-6 ◽  
Author(s):  
T. Brey ◽  
C. Dahm ◽  
M. Gorny ◽  
M. Klages ◽  
M. Stiller ◽  
...  

Depth distribution data were compared for 172 European and 157 Antarctic benthic invertebrate species occurring in the respective shelf areas. Antarctic species showed significantly wider depth ranges in selected families of the groups Bivalvia, Gastropoda, Amphipoda and Decapoda. No differences were found in Polychaeta, Asteroidea and Ophiuroidea, where European species also showed comparatively wide bathymetric ranges. These extended levels of eurybathy in the Antarctic benthos may be interpreted either as an evolutionary adaptation or pre-adaptation to the oscillation of shelf ice extension during the Antarctic glacial-interglacial cycle.

2010 ◽  
Vol 22 (5) ◽  
pp. 494-507 ◽  
Author(s):  
Sergi Taboada ◽  
Luis Francisco García-Fernández ◽  
Santiago Bueno ◽  
Jennifer Vázquez ◽  
Carmen Cuevas ◽  
...  

AbstractA prospecting search for antitumoural activity in polar benthic invertebrates was conducted on Antarctic and sub-Antarctic benthos in three different areas: Bouvet Island (sub-Antarctic), eastern Weddell Sea (Antarctica) and the South Shetland Islands (Antarctica). A total of 770 benthic invertebrate samples (corresponding to at least 290 different species) from 12 different phyla were assayed to establish their pharmacological potential against three human tumour cell lines (colorectal adenocarcinoma, lung carcinoma and breast adenocarcinoma). Bioassays resulted in 15 different species showing anticancer activity corresponding to five different phyla: Tunicata (5), Porifera (4), Cnidaria (3), Echinodermata (2) and Annelida (1). This appears to be the largest pharmacological study ever carried out in Antarctica and it shows very promising antitumoural activities in the Antarctic and sub-Antarctic benthos.


1981 ◽  
Vol 32 (2) ◽  
pp. 191 ◽  
Author(s):  
DR Towns

Life histories of the following 12 benthic invertebrate species were investigated at four sites in the Waitakere River: Potamopyrgus antipodarum (Gastropoda : Hydrobiidae); Paracalliope fluviatilis (Amphipoda : Eusiridae), Zephlebia (Neozephlebia) sp. and Deleatidium spp. (Ephemeroptera : Leptophlebiidae), Hydora nitida (Coleoptera : Elmidae), Maoridiamesa harrisi, ?Austrocladius sp. and Paratanytarsus agameta (Diptera : Chironomidae), Austrosimulium australense (Diptera : Simuliidae), Aoteapsyche colonica (Trichoptera : Hydropsychidae), Oxyethira albireps (Trichoptera : Hydroptilidae), and Olinga feredayi (Trichoptera : Conoesucidae). All species had life cycles which were non-seasonal according to the Hynes model. Comparison with recent studies in southern North Island and South Island streams suggests that non-seasonal life cycles predominate in New Zealand streams.


2015 ◽  
Vol 1 (10) ◽  
pp. e1500050 ◽  
Author(s):  
Ricardo Sahade ◽  
Cristian Lagger ◽  
Luciana Torre ◽  
Fernando Momo ◽  
Patrick Monien ◽  
...  

The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a “filter feeders–ascidian domination” to a “mixed assemblage” suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.


2002 ◽  
Vol 38 (3) ◽  
pp. 8
Author(s):  
V. V. Murina ◽  
Ye. V. Lisitskaya ◽  
V. K. Shalyapin

1983 ◽  
Vol 40 (5) ◽  
pp. 637-643 ◽  
Author(s):  
C. W. Pugsley ◽  
H. B. N. Hynes

A freeze-coring device using liquid nitrogen is described, which enables one person to take a columnar core, extending from the surface to at least 50 cm below a stony streambed. An experiment to validate the technique showed that animals did not flee from the advance of the freezing-front. Using frozen streambed cores, the vertical distribution of benthic invertebrates of two streams in southern Ontario was investigated. In contrast to previous estimates,~70% of the fauna was found in the top 10 cm of the streambed, and invertebrate densities were often lower by an order of magnitude. These differences are attributed to problems of quantifying previous sampling methods.


Author(s):  
Alexenko T. ◽  
Shevchenko I.

For the first time, systematic studies of the structural and functional properties of macrozoobenthos of Lake Zakіtne were conducted. A taxonomic list of macroinvertebrates with their zoogeographical characteristics is given. According to the results of research, 3 types of benthic invertebrate groups were identified and described, of which Oligochaeta-Chironomidae type were the most widespread. Only two species were common to all found groups: Einfeldia longipes and Glyptotendipes glaucus of Chiromonidae family. The calculated biotic indices indicate a fairly high degree of use of existing biotopes by macroinvertebrates, as well as the predominance of species characteristic of the α-β-mesosaprobic zone.The variety of ways and mechanisms of feeding of benthic invertebrates is shown. Collectors, scraper collectors, sedimentators, filter feeders, shredders, predators, as well as macroinvertebrates with an indeterminate feeding type were identified in the trophic structure by the predominant type of feeding. The number of species, as well as their representation in trophic groups, varied in different years, yet 54-73% of them were nonpredatory forms.According to the obtained data, the components of the energy balance for macroinvertebrates were calculated. The active participation in the production of organic matter of Chironomidae larvae (from 29 to 62% of the total production of nonpredatory and predatory forms) is indicated. In some years, Ephemeroptera and Mollusca were actively involved in production. The largest flow of energy passed through insects (Ephemeroptera, Trichoptera) and leeches. Attention is drawn to the role of predators, which can significantly reduce the production of groups. High production and food ration of predators do not allow to ignore them when calculating the production of the entire zoocenosis.In average, during the vegetation season, the total production of nonpredatory and predatory benthic invertebrates was 77,89 kJ/m2, and the predator's food ration was 61,80 kJ/m2.Key words:macroinvertebrates, taxonomic structure, trophic structure, community, production, food ration, energy balance. Вперше проведено систематичні дослідження структурно-функціональних властивостей макрозообентосу озера Закітне. Наведено таксономічний список макробезхребетних з їх зоогеографічною характеристикою. За результатами досліджень виявлено та описано 3 типи угруповань донних безхребетних, з яких найбільшепоширення отримали олігохетно-хірономідні комплекси. Лише двавиди виявилися спільними для всіх знайдених угруповань: Einfeldia longipes і Glyptotendipes glaucus (родина Chironomidae).Розраховані біотичні індекси свідчать про достатньо високий ступень використання існуючих біотопів макробезхребетними, а також про переважання видів, що характерні для α-β-мезосапробної зони.Показанарізноманітність способів і механізмів живлення донних безхребетних. У трофічній структурі угруповань за переважаючим способомживлення було виділено збирачів, збирачів-шкребачів, седиментаторів, фільтраторів, подрібнювачів, хижаків, а також макробезхребетних із невизначеним типом живлення. Кількість видів, а також їх представленість утрофічних групах в різні роки була неоднакова, але на 54–73% це були мирні форми.За отриманими даними було розраховано складові енергетичного балансу за макробезхребетними. Вказано на активну участь упродукуванні органічної речовини личинок родини Chironomidae, яким належить від 29 до 62% від сумарної продукції мирних і хижих форм. В окремі роки в продукування активно включалися одноденки та молюски. Найбільший потік енергії проходив через комах (Ephemeroptera, Trichoptera) і п’явок. Звернуто увагу на роль хижаків, які можуть суттєво знижувати продукцію угруповань. Високапродукція і раціон хижаків не дозволяють нехтувати ними при розрахунку продукції всього ценозу.Підраховано, що в середньому за вегетаційний період сумарна продукція мирних і хижих донних безхребетних дорівнювала 77,89 кДж/м2, а раціон хижаків складав 61,80 кДж/м2.Ключові слова: макробезхребетні, таксономічна структура, трофічна структура, угруповання, продукція, раціон, енергетичний баланс.


2007 ◽  
Vol 362 (1488) ◽  
pp. 2187-2189 ◽  
Author(s):  
Alex D Rogers ◽  
Eugene J Murphy ◽  
Nadine M Johnston ◽  
Andrew Clarke

The Antarctic biota has evolved over the last 100 million years in increasingly isolated and cold conditions. As a result, Antarctic species, from micro-organisms to vertebrates, have adapted to life at extremely low temperatures, including changes in the genome, physiology and ecological traits such as life history. Coupled with cycles of glaciation that have promoted speciation in the Antarctic, this has led to a unique biota in terms of biogeography, patterns of species distribution and endemism. Specialization in the Antarctic biota has led to trade-offs in many ecologically important functions and Antarctic species may have a limited capacity to adapt to present climate change. These include the direct effects of changes in environmental parameters and indirect effects of increased competition and predation resulting from altered life histories of Antarctic species and the impacts of invasive species. Ultimately, climate change may alter the responses of Antarctic ecosystems to harvesting from humans. The unique adaptations of Antarctic species mean that they provide unique models of molecular evolution in natural populations. The simplicity of Antarctic communities, especially from terrestrial systems, makes them ideal to investigate the ecological implications of climate change, which are difficult to identify in more complex systems.


2013 ◽  
Vol 47 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Michael Schäffer ◽  
Carola Winkelmann ◽  
Claudia Hellmann ◽  
Jürgen Benndorf

<em>Abstract.</em>—Extensive trawling efforts off Taiwan, supplemented by collections from trawlers’ harvest at several local fishing harbors, have raised the total number of Taiwan’s grenadier fishes to 71 species in 18 genera and 3 families. Despite a relatively limited coastline (500 nautical miles), the species diversity in Taiwan is very high. The largest genus <em>Coelorinchus </em>(formerly known as <em>Caelorinchus</em>) is represented by 21 species, followed by <em>Ventrifossa </em>with 8, and <em>Nezumia </em>with 6. All other genera had five or fewer representatives. Five species were described based on specimens from Taiwan, and two of them, <em>Coelorinchus leptorhinus </em>and <em>C. sheni, </em>have not been reported elsewhere. A total of 33 species and 10 genera are newly recorded from Taiwan; these were collected only within the past two years. Because the maximum depth trawled only reached about 2,000 m in this study, it should be expected that more deeper-water grenadiers will be found in the future. Our depth-distribution data-set of collected specimens and depth ranges from 55 stations were insufficient to effectively separate the species into groups using multivariate statistical analysis. However, the factors influencing grenadier species composition in this study still can be recognized as per the following sequence: water depth, geographical region, and type of net. The vertical distribution of grenadiers in Taiwan appears to have a separation at 600 m and 1000 m. An annotated species checklist with ASIZP cataloged specimens documenting Taiwan distributions, and detailed collecting information, including body size, location, and depth range are provided.


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