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To understand the response of marine ecosystem to Antarctic environmental changes such as Ozone depletion and global warming it is necessary to determine the extent to which ecological variations are driven by environmental fluctuations. As a first step in investigating the response of marine ecosystems to environmental change we need to characterize the variability spectrum of the environment. Any long-term environmental change may be resolved with investigation of suitable time series for determining the natural variability of the marine ecosystem.
Antarctic nearshore ecosystem has been threatened by environmental changes such as ozone depletion, global warming, and anthrophogenic pollution. Marine organisms in nearshore areas can be used as an important biological parameters to detect and monitor the environmental change. Antarctic marine organisms have been adapted in low light and temperature. Thus small-scale changes in their environment such as UV radiation and temperature can result in affecting their community structure. Especially, microalgae are major primary producer to sustain Antarctic marine ecosystem, thus their change means change of whole marine ecosystem.
The objectives of the study were to 1) understand biological response to environmental changes, 2) to develope standardized representative natural and biological parameters, 3) to find indicator species to be used as biological indicators of environmental changes near King Sejong Station, Antarctica. |
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| To understand biological response to environmental changes, to develope standardized representative natural and biological parameters, and to find indicator species to be used as biological indicators of environmental changes near King Sejong Station, Antarctica, the following contents were studied. |
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Biological indicators of global environmental changes near King Sejong Station
UV Effect on Ecology and Physiology of Microalgae by Depletion of Antarctic Ozon Layer
Effect of UV radiation on marine macroalgae
Development of genetic markers and Studies on evolution and systematics of Sterechinus neumayeri |
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1. Marine primary producers such as micro- and macroalgae, which are pioneer endemic species and important carbon contributors in the Antarctic waters, are therefore highly suitable biological indicators of Antarctic environmental changes such as ozone depletion and global warming. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the Antarctic waters. This light-dependent process is vulnerable to environmental change because of the restriction of their growth to the shallow photic zone. Although the primary producers respond rapidly to environmental changes, the rate of climate change is relatively slow despite its long-term significance.
2. There is concern that phytoplankton communities confined to surface water of Antarctic Sea and coastal environment will be harmed by increased UVR penetrating the surface water, thereby altering the dynamics of Antarctic marine ecosystems. Thus it is essential to quantify UV-related effects on aquatic ecosystems under natural conditions and to elucidate regulating mechanisms underlying UVR impairment of phytoplankton biology. Increases in incident UV levels will most likely result in changes in the taxonomic structure of communities. Various UV-related effects that change of phytoplankton communities, tolerance, ecological adaptation, and physiology have been reviewed in order to understand the resultant variation of UVR that could bring harmful effects to marine ecosystem in the Antarctic.
3. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. In addition to the repair process, the function of UV-absorbing pigments to protect photosynthetic pigments inside the thallus from UV-damage has been demonstrated in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. Reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem.
4. The unique environment of Antarctica such as low temperature has helped development of lots of endemic species in that region. Of the 44 species of echinoids in coastal Antarctica, 34 (77%) are endemic. With regard to evolutionary origin of Antarctic endemic species, little is known yet. In this study, we tried to obtain the nucleotide sequence of mitochondrial genes of Sterechinus neumayeri, cytochrome oxidase subunit I (COI), NADH dehydrogenase subunit I (NDI), and 12SrDNA/control region, in order to establish molecular phylogeny of the species and to use the sequence as genetic markers for environmental monitoring of the species. First, genomic DNA was extracted from the 70% alcohol fixed gonads of the species. Then, a region of each COI, NDI, and 12SrDNA/control region gene was amplified directly from the genomic DNA through polymerase chain reaction (PCR), and the PCR product was cloned and sequenced: 1126 nucleotides of COI and 706 nucleotides of 12SrDNA/control region were obtained. |
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There is increasing evidence of climate change in the Antarctic, especially elevated temperature and ultraviolet B (UV-B) flux within the ozone "hole." Its origins are debatable, but the effects on ice recession, water availability, and summer growth conditions are demonstrable. Light-dependent, temperature-sensitive, fast-growing organisms respond to these physical and biogeochemical changes.
Marine primary producers such as micro- and macroalgae, which are pioneer endemic species and important carbon contributors in the Antarctic waters, are therefore highly suitable biological indicators of such changes. By virtue of light requirement, the primary producers are exposed to extreme seasonal fluctuations in temperature, photosynthetically active radiation, and UV radiation. The physical changes in climate, although significant in the long term, are gradual. The changes can be therefore amplified experimentally. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the Antarctic waters.
Small elevations in climate temperature may have profound effects on the activity threshold of the primary producers. Long-term research has focused on the ability of the primary producers to initiate the growing process on recently deglaciated groud. This light-dependent process is vulnerable to environmental change because of the restriction of their growth to the shallow photic zone. Although the primary producers respond rapidly to environmental changes, the rate of climate change is relatively slow despite its long-term significance.
To demonstrate biological response to change, standardized representative natural and biological parameters are needed so that replicate samples (including controls) can be taken over extended periods of time. Throughout the study, we expect to understand environmental changes in the Antarctic and the effects on primary producers and to find indicator species to be used as biological indicators of environmental changes near King Sejong Station, Antarctica. | |
Research Activities > Major Topics > Marine Ecosystem & Environmental Change
