The Antarctic ecosystem

The Antarctic region comprises the continent and surrounding sea south of the Antarctic Convergence, where cold Antarctic upper water sinks and mixes with warmer sub-Antarctic water. The continent, nearly centered on the South Geographic Pole, is isolated by the Southern Ocean from other land masses. The continent's mean elevation is about 2,000 m and 98% of the surface is mantled by 2,000 m or more of glacial ice which flows toward coastal outlets to the sea. The ice sheet is pierced by mountain summits, some approaching altitudes near 5,000 m. The continental shelf mean width is 30 km. On its seaward edge the shelf is at depths of 400 to over 600 m. The total area of ice and snow surface presented by the region is doubled by the maximum extent of sea ice each year. The Antarctic Continent is the principal heat sink of the world weather machine. Upwelling areas of the Southern Ocean recycle nutrients and stimulate the marine ecosystem, and seasonal changes in extent of sea ice contribute to one of the greatest annual pulses in marine organic production. The fish fauna has only 120 species but these belong to 29 families. The zooplankton is rich in several endemic crustacea, notably the Antarctic krill. The only vertebrates on land come from the sea onto shore areas and fast ice, including colonies of breeding penguins and associated birds as well as seals. Closed communities of vascular plants and cryptogams occur on sub-Antarctic islands and the Antarctic Peninsula, but in the entire continental Antarctic the vegetation is desert-like, composed of scattered mosses, lichens, and terrestrial algae. Exposed surfaces of crystalline rocks harbor “endolithic microbial life,” and a few species of invertebrates dwell on favorably exposed soil and under rocks. The ice Plateau is as nearly abiotic or sterile as any area on the earth's surface. The physical and biotic features of Antarctica represent extreme conditions. The continent was untouched by man until the past two centuries and remains nearly pristine. It yields key information about cold environments and global environmental systems including evidences of change, and deserves protection from unnecessary disturbance.     

Conservation and the Antarctic environment: The working group reports of the joint IUCN/SCAR Symposium on the scientific requirements for Antarctic conservation

Six working groups were set up at the joint IUCN/SCAR Symposium on the scientific requirements for Antarctic conservation. These were charged with (i) identifying gaps in the scientific understanding of ecosystems that inhibit rational management, and (ii) considering whether present conservation practices were taking enough account of what is known of the region, particularly with regard to protected areas. There is still a need for synthesis and further work on stocks and the life history of krill in the pelagic ecosystem. Monitoring strategies are not clear and biomass determinations are difficult and costly. Information on squid is lacking. Although there is much information on higher consumers there is a gap in knowledge of dynamic ecological processes, particularly in winter. Studies of crabeater seals deserve priority. The network of existing protected areas is inadequate for preserving all species of birds, seals and whales; new criteria are needed for effective conservation. On land, the Agreed Measures provide an adequate framework for conservation, though additional steps are needed to ensure adherence to their provisions. Selection criteria are deficient. Additional measures are required; these include the establishment of Conservation Areas, general provision for the protection of biota, and a code of conduct for all activities. Exploitation of marine mammals (except the minke whale) has ceased. Monitoring whales presents difficulties. Fish stocks are significantly exploited and better monitoring is required. Prediction of trends in krill catches is difficult but there has been a large drop in krill fishing effort. Localised effects on predators could occur with catches of a few million metric tons. Commercial mineral exploitation in the Antarctic is a long way in the future but exploitation could result from political motives. There is a need for a data base for the design of investigations and impact assessment. Operational hazards need to be modelled in advance. It is important not to go too far too fast. Antarctica is unique in its control measures and their implementation. However, Specially Protected Areas lack management plans and management plans at Sites of Special Scientific Interest are not consistent. There are inadequate guidelines on the development of scientific stations. The coastal region must be regarded as critical habitat. A comprehensive conservation strategy is required with a broader network of protected areas giving full consideration to marine as well as terrestrial areas. Copies of the full working group reports have been deposited with IUCN and SCAR.     

Local perspectives on regional challenges: jellyfish proliferation and fish stock management along the Israeli Mediterranean coast

The composition and abundance of marine biota in Israeli marine ecosystems are affected by natural and anthropogenic pressures, including blooms of non-indigenous jellyfish and overfishing. While overfishing is itself a major stressor of fish stocks, it appears that jellyfish may be outcompeting fish for scarce planktonic food resources. Beyond this direct impact on fisheries, jellyfish–ecosystem interactions are also important because of the disturbance they cause to multiple users of marine and coastal resources. This paper documents the concurrent changes in the composition of marine biotic communities, including jellyfish proliferation and dwindling stocks of endemic, commercially valuable fish and the rising rate of bottom trawling in Israeli fisheries. The capacity to deal directly with jellyfish is limited by lack of knowledge about their ecology. Therefore, we suggest that bolstering fish stocks and increasing their competitive advantage in the food web may be instrumental in limiting jellyfish blooms. Coordination of fishing and conservation policies is recommended, as are modifications to marine waste management and deployment of submerged artificial substrates.     

Criteria for protected areas and other conservation measures in the Antarctic region

The Antarctic region is threatened by three major anthropogenic influences: climatic change brought about by increases in atmospheric carbon dioxide, the effects of persistent pollutants carried into the region via atmosphere and ocean, and the increase in Man's activities. Vulnerable ecosystems can be considered as those which are under direct pressure from Man's activities, whereas fragile ecosystems are the more likely to suffer irreversible change when perturbed, but are not necessarily threatened at present. Three of the main habitat types, terrestrial, inland waters, and islands, are likely to be fragile. However, all these can be conserved reasonably adequately with a system of protected and managed areas, so long as the area covered is adequate and representative. The fourth habitat type, the oceanic ecosystem, contains few fragile elements because it is dominated by the highly dynamic physical oceanic processes. Elements of the ecosystem are vulnerable to further exploitation, and although only the whales and some of the fish stocks can be regarded as fragile, there is considerable uncertainty as what synergistic effects exploitation of apparently key elements of the ecosystem, such as the krill, will have on other important components of the communities. The highly dynamic structure of oceanic environments renders the concept of conservation based on limited protected areas developed for terrestrial environments ineffective in the majority of marine environments. Instead the whole marine environment of the Antarctic region must be considered to be a single entity and managed as such.     

(137)Cs concentrations in Atlantic and western Antarctic surface waters: results of the 7th Ukrainian Antarctic Expedition, 2002

The latitudinal distribution of (137)Cs in the Atlantic--western Antarctic surface waters was studied during the 7th Ukrainian Antarctic Expedition in January--May 2002. The (137)Cs concentrations have also been measured in the upper ice of the coastal glacier Woozle Hill located near the Ukrainian Antarctic station "Akademik Vernadsky" (western Antarctica, 65 degrees 15' S-64 degrees 16' W). Comparison of these data with results of previous same-route expeditions SWEDARP (Swedish Antarctic Research Expedition, 1988/1989) and the French R/V "Jeanne d'Arc" (1992/1993), has shown practically parallel changes of (137)Cs surface concentrations between 40 degrees N and 20 degrees S, pointing to decrease of (137)Cs radioactivity at these latitudes with an apparent half-life of 10--15 years (12.5+/-2.1 years on average). This suggests that decrease of (137)Cs surface concentration within this latitude band is controlled, besides the radioactive decay of (137)Cs (half-life=30 years), by vertical mixing of the upper water masses. South of 20 degrees S, the (137)Cs concentrations in surface water have decreased more rapidly because of the influence of the less contaminated Antarctic waters. At 50--60 degrees S and near the Antarctic coast, the (137)Cs activity in 2002 was similar to those measured during the SWEDARP and "Jeanne d'Arc" expeditions, suggesting an additional input of (137)Cs to these waters from the melted ice from the adjacent glaciers.     

Practising the past in the present: using Ghanaian indigenous methods for water quality determination in the contemporary era

Surface water sources remain the dominant sources of water supply for a significant proportion of poor communities. These water supply sources tend to have low water quality levels. Application of water quality determination and purification measures could minimize water-related diseases associated with direct consumption of water with poor quality levels. A number of simple measures have been devised and utilized by indigenous communities based on their resource conservation knowledge to improve water quality levels. However, scientific approaches that are more in tune with modern demands for reliability and exactness are the preferred, mainstream approaches for determining water quality. Growing recognition of the relevance of indigenous knowledge has led to renewed interest in the possibility of utilizing it for such tasks. Research conducted in 2007 and 2008 in two indigenous communities in Ghana revealed a diversity of indigenous methods for water quality determination and purification including straining, settling and use of special seeds which could still be useful in this contemporary era. This paper recommends that knowledge co-production and transdisciplinary approaches be employed to enable indigenous communities and experts to collaborate and develop measures that tap both knowledge systems for improving water quality levels for human use.     

Impact of human activities on the geomagnetic field of Antarctica: A high resolution aeromagnetic survey over Mario Zucchelli Station

Environmental protection of Antarctica is a fundamental principle of the Antarctic Treaty. Impact assessment and significance evaluation are due for every human activity on the remote continent. While chemical and biological contaminations are widely studied, very little is known about the electromagnetic pollution levels. In this frame, we have evaluated the significance of the impact of Mario Zucchelli Antarctic Station (Northern Victoria Land) on the local geomagnetic field. We have flown a high resolution aeromagnetic survey in drape mode at 320 m over the Station, covering an area of 2 km². The regional and the local field have been separated by a third order polynomial fitting. After the identification of the anthropic magnetic anomaly due to the Station, we have estimated the magnetic field at the ground level by downward continuation with an original inversion scheme regularized by a minimum gradient support functional to avoid high frequency noise effects. The resulting anthropic static magnetic field at ground extends up to 650 m far from the Station and reaches a maximum peak to peak value of about 2800 nT. This anthropic magnetic anomaly may interact with biological systems, raising the necessity to evaluate the significance of the static magnetic impact of human installations in order to protect the electromagnetic environment and the biota of Antarctica.     

Macrozoobenthos as an indicator of the ecological state of mountain watercourses

Structural characteristics of benthic macroinvertebrate communities in mountain watercourses of different sizes have been studied in the Upper Ob basin. It has been found that species richness, diversity of zoobenthos, and most biotic indices in the background areas increase in the series from the smallest watercourses to large rivers. On the contrary, the values of the above parameters in areas polluted with mercury has proved to decrease, thereby indicating a significant transformation of the benthic communities. Approaches are proposed to select reference indices for assessing the ecological state of watercourses in the basin with regard to the size of the river, the structure of benthic communities, and variability of biotic indices along the background cross sections.     

乌江梯级电站开发对大型底栖无脊椎动物群落结构和多样性的影响

为了解乌江贵州段的底栖动物资源现状以及梯级电站开发对底栖动物群落结构和多样性的影响,对18个断面的底栖动物进行了调查。底栖动物多样性通过Shannon Wiener多样性指数进行计算。结果显示：自然河段中,底栖动物物种丰富,以节肢动物占优势,物种丰富度和密度均以思南断面最高,生物多样性则以沿河二桥断面最高;群落类型复杂,环节动物 软体动物 节肢动物为优势群落,软体动物为群落中的优势类群。梯级水库的修建使底质环境差异变小,底栖动物物种丰度、密度和生物多样性降低,群落类型趋于简单,优势类群表现不明显,并且水库建成的年代越久,底栖动物的丰度、密度就越低,群落的组成类群就越少,物种组成以寡毛类和摇蚊类为主。研究表明,梯级电站的修建对底栖动物的物种组成、密度分布、多样性、群落类型等都造成了负面影响。〖     

The Antarctic Treaty System: Environmental protection,conservation, and the question of competing use

The Antarctic Treaty System consists of the Treaty itself, over 130 recommendations made under it, the Agreed Measures for the Conservation of Antarctic Fauna and Flora, the Convention for the Conservation of Antarctic Seals, and the Convention for the Conservation of Antarctic Marine Living Resources. Consultations have been held among parties to the Antarctic Treaty to elaborate an Antarctic minerals regime. It has become clear that how to deal with issues of competing use has begun to emerge as an important political question. In such a context the development of an Antarctic conservation strategy is a potentially helpful step. Competition of use, when it occurs, will be localised and different in different areas. In only tiny parts will it be severe, but these parts may be the biologically richest coastal areas. Various activities and their possible interactions are considered. It is concluded that any arrangement of Antarctic activities which given an automatic priority of one over others is wrong. Similarly, no activity should be subservient to all others. An Antarctic conservation strategy needs to be developed and in its operation the concept of adaptive environmental assessment and management needs to be applied. Within the Antarctic Treaty System there are moves towards assessment. What is needed now is a framework within which such concepts can operate; that is, a conservation and environmental strategy.     

Relationship between the Biodiversity of phyto- and zoobenthos in the continuum of the model mountain river Komarovka (Primorye,Russia)

The structure of benthic communities was studied in the continuum of the model mountain river Komarovka, which flows in the conifer-broadleaf forest subzone in the southwest of the Silkhote-Alin Mountain Range (Primorye, Russia). The lowest species diversity of phyto- and zoobenthos was recorded in the upper reaches of the river, in a heterotrophic area; the highest species diversity, in the central part of autotrophic area. At the same time, the Shannon index for algal communities had the highest values in the heterotrophic area, while that for bottom invertebrate communities, within the autotrophic area. Thus, the increase in invertebrate species diversity in the river continuum was accompanied by complication of the structure of zoobenthos, while the increase in the taxonomic diversity of phytobenthos took place against the background of increasing dominance of a few algal species.     

Trophic structure of invertebrate communities in ecosystems of salmon rivers in the southern Far East

The formation of trophic structure has been studied in communities of amphibiotic insects (mayflies, stoneflies, caddis flies, and dipterans) and gammarids accounting for 90% of the total benthos biomass. The results show that the trophic groups prevailing by biomass in the metarithral subzone of small rivers are as follows: filtering collectors in rivers of the moderately cold-water type, collectors and scrapers in rivers of the cold-water type, and scraping predators and scrapers in rivers of the moderately warm-water type. Predators, scraping predators, and scrapers show seasonal changes in abundance and biomass. In the rithron of Far Eastern rivers, the abundance of predators regularly decreases in a south-north direction. The change of dominant groups along the longitudinal profile of the river is related to its zones and subzones. In the trophic structure of rivers exposed to anthropogenic impact, the number of trophic groups decreases and the remaining groups undergo changes in their qualitative composition and the ratio of their individual members.     

ABORIGINAL PEOPLE’S ATTITUDES TOWARDS PAYING FOR WATER IN A WATER-SCARCE REGION OF AUSTRALIA

In Australia, governments are committed to water infrastructure developments that are both environmentally sustainable and economically viable. Consumption-based pricing is seen as a water conservation strategy. This has significant implications for Aboriginal communities, many of which do not pay for water use and experience economic hardship. This paper outlines attitudes towards paying for water use in five Aboriginal communities in South Australia. Inability to pay for services was a common factor hindering willingness to pay for water. While different factors were raised in different communities, most communities believed that water is a ‘cultural right’ that should not be paid for. The research found that strategies such as communication and community involvement in the decision-making processes around water supply are necessary to facilitate cost recovery and to promote water conservation.     

Phylogenetic diversity scaling in small mammal communities: The example of Nizhny Novgorod region of the Volga Basin

Traditional approaches to structural analysis of biotic communities, based on the data on species abundances, do not take into account phylogenetic relationships between these species. We propose a new approach to studying the scaling (scale dependence) of phylogenetic diversity by means of multifractal analysis in which the moments of phylogenetic diversity are used. The results of applying this approach to small mammal communities of Nizhny Novgorod region of the Volga Basin has shown that phylogenetic diversity scaling complies with the power law, which is indicative of the self-similarity of these communities. The multifractal spectra of phylogenetic diversity scaling markedly differ from the spectra of species diversity scaling, providing evidence that the proposed approach can provide novel information on the structure of biotic communities.     

Empirical and theoretical evidence concerning the response of the earth's ice and snow cover to a global temperature increase

As a guide to the possible effects of a CO₂-induced warming on the cryosphere, we review the effects of three warm periods in the past, and out theoretical understanding of fluctuations in mountain glaciers, the Greenland and Antarctic ice sheets, ground ice, sea ice and seasonal snow cover. Between 1890 and 1940 A.D. the glaciated area in Switzerland was reduced by over 25%. In the Hypsithermal, at about 6000 BP, ground ice in Eurasia retreated northward by several hundred kilometres. In the interglacial Stage 5e, at about 120 000 BP, global sea-level rose by over 6 m. Fluctuations of mountain glaciers depend on mesoscale “weather” and on their mechanical response to it. Any melting of the Greenland ice sheet is likely to be slow in human terms. The West Antarctic ice sheet (its base below sea-level) is susceptible to an ungrounding, and such an event may have been the cause of the sea-level rise above. The East Antarctic ice sheet is susceptible to mechanical “surges”, which might be triggered by a warming at its margin. Both an ungrounding and a surge might occupy less than 100 yr, and are potetially the most important ice changes in human terms. Modelling studies suggest that a 5°C warming would remove the Arctic pack ice in summer, and this may be the most significant effect for further climatic change.     

Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments

Sediments act as a net sink for anthropogenic contaminants in marine ecosystems and contaminated sediments may have a range of toxicological effects on benthic fauna and associated species. When resuspended, however, particulate-bound contaminants may be remobilised into the water column and become bioavailable to an additional assemblage of species. Such resuspension occurs through a range of natural and anthropogenic processes each of which may be thought of as pulsed disturbances resulting in pulsed exposures to contaminants. Thus, it is important to understand not only the toxicological responses of organisms to resuspended contaminated sediments (RCS), but also the frequency, magnitude and duration of sediment disturbance events. Such information is rarely collected together with toxicological data. Rather, the majority of published studies (> 50% of the articles captured in this review) have taken the form of fixed-duration laboratory-based exposures with individual species. While this research has clearly demonstrated that resuspension of contaminated sediments can liberate sediment-bound contaminants leading to toxicity and bioaccumulation under controlled conditions, the potential for ecological effects in the field is often unclear. Monitoring studies suggest that recurrent natural disturbances such as tides and waves may cause the majority of contaminant release in many environments. However, various processes also act to limit the spatial and temporal scales across which contaminants are remobilised to the most toxic dissolved state. Various natural and anthropogenic disturbances of contaminated sediments have been linked to both community-level and sub-lethal responses in exposed populations of invertebrates and fish in the field. Together these findings suggest that resuspension of contaminated sediments is a frequently recurring ecological threat in contaminated marine habitats. Further consideration of how marine communities respond to temporally variable exposures to RCS is required, as well as research into the relative importance of various disturbances under field conditions.     

月湖底栖动物的空间格局及其对水草可恢复区的指示

底质适宜是富营养湖泊恢复沉水植物(水草)的重要前提。大型底栖动物可综合指示底质的污染程度,于2002~2003年在武汉月湖开展了底栖动物水平分布对水草可恢复区指示作用的研究。首先通过月湖底栖动物与环境的相关分析,选择颤蚓科寡毛类作为底质营养状况的指示类群,然后利用同类湖泊群颤蚓与水草数据分析阈值,初步确定颤蚓密度≤100 ind/m2的底质适合水草生长,最后绘制月湖颤蚓分布的水平等值线,显示水草恢复的合适区域。在此基础上构建了应用底栖动物空间格局指示水草恢复区的技术原理框架。     

Basic Tendencies in the Structural Dynamics of Phytoplanktonic and Benthic Communities in the Sea of Azov

New data on the present-day state of planktonic and benthic communities in the Sea of Azov were obtained during an expedition organized in 1997 and 1998. The analysis of their species composition and quantitative indices of biomass and abundance revealed two obvious tendencies in the structural dynamics of biocenoses. The first is directly produced by disturbances of the environment under anthropogenic impact, and the second reflects the effect of global natural factors.     

Radionuclides deposition over Antarctica

A detailed and comprehensive map of the distribution patterns for both natural and artificial radionuclides over Antarctica has been established. This work integrates the results of several decades of international programs focusing on the analysis of natural and artificial radionuclides in snow and ice cores from this polar region. The mean value (37+/-20 Bq m(-2)) of (241)Pu total deposition over 28 stations is determined from the gamma emissions of its daughter (241)Am, presenting a long half-life (432.7 yrs). Detailed profiles and distributions of (241)Pu in ice cores make it possible to clearly distinguish between the atmospheric thermonuclear tests of the fifties and sixties. Strong relationships are also found between radionuclide data ((137)Cs with respect to (241)Pu and (210)Pb with respect to (137)Cs), make it possible to estimate the total deposition or natural fluxes of these radionuclides. Total deposition of (137)Cs over Antarctica is estimated at 760 TBq, based on results from the 90-180 degrees East sector. Given the irregular distribution of sampling sites, more ice cores and snow samples must be analyzed in other sectors of Antarctica to check the validity of this figure.     

Designing conservation-development policies for the forest frontier

The conservation of forests in expanding frontier landscapes is critically important to maintain intact forest ecosystems and support forest dependent communities. To conserve frontier forests, policy approaches are needed that conserve forests and advance the well-being of local resource dependent communities. To identify such approaches, the forest conservation and development framework (FCDF) was designed to find place-based conservation-development policies that target system leverage-points influencing land-use practices. To demonstrate the utility of the FCDF, a portfolio of conservation-development policies were identified for Peru’s Manu-Tambopata Corridor (MAT) and evaluated by local land-users. Results of the MAT case study show high levels of interest in the proposed policies, but a wide variation in interest levels relative to personal circumstances and policies proposed. Barriers to implementing conservation-development policies in frontier environments were also identified, including high value land-use alternatives generating high opportunity costs for accepting PES payments (e.g., REDD+), insecure land tenure and conflicting authorizations limiting land-users policy choices, and broad demographic diversity among local land-users. Collectively, this research suggests the FCDF is a useful approach for identifying policies matched to local conditions that advance conservation and human development. This research also indicates policy design in frontier environments is most effective when adapted to local conditions, seeks to identify a mix of complementary policies, and is targeted at key system variables influencing land-use practices (i.e., system leverage-points). Importantly, the MAT case study also highlights how even in rapidly changing frontier landscapes, land-users are interested in policies that advance conservation and development goals.