초록 ▼

o 수산과학원 한국해양자료센터 (KODC) 와 위성/관측기지를 통해 확보한 과거 26 년간의 자료와 본 사업 (2008~2010)을 통해 획득한 남해 주요 연안역 현장조사결과를 바탕으로 남해에서 기후변화(수온상승+산성화) 취약 연안역은 마산 진해만 부산앞바다 제주 조천 앞바다로 나타났으며 비교적 완만하게 기후변화 영향을 받은 연안역으로는 고흥 진도완도연안 득량만 등으로 나타났다. 그리고 위의조사결과를 바탕으로 남해 연안역 기후변화 취약 지역에서의 기후변화 영향 감시 및 평가를 위한 해양 환경 모니터링(현장관측 위성활용 관측부이) 체

o 수산과학원 한국해양자료센터 (KODC) 와 위성/관측기지를 통해 확보한 과거 26 년간의 자료와 본 사업 (2008~2010)을 통해 획득한 남해 주요 연안역 현장조사결과를 바탕으로 남해에서 기후변화(수온상승+산성화) 취약 연안역은 마산 진해만 부산앞바다 제주 조천 앞바다로 나타났으며 비교적 완만하게 기후변화 영향을 받은 연안역으로는 고흥 진도완도연안 득량만 등으로 나타났다. 그리고 위의조사결과를 바탕으로 남해 연안역 기후변화 취약 지역에서의 기후변화 영향 감시 및 평가를 위한 해양 환경 모니터링(현장관측 위성활용 관측부이) 체계를 구축하여 2011 년 6월부터 시험 운용하였고 현장조사 결과 및 실시간 부이관측자료 제공을 위한 DB를 구축하였다,
o 1980 년 이후 남해역의 온난화는 빠르게 진행("" +0.4℃/lO년)되어 아열대 산호 번식 가능 수온인 겨울철 18℃ 해수등온선이 약 50-100 km 북상한 것으로 나타났다. 계절별로는 여름철에 공간적으로는 제주 북서쪽 해역에서 더 급속한 해수온 상승이 진행되고 있으며 본 연구해역의 수온변동은 기싱변화(엘니뇨 극진동 등)와 상관성이 높게 나타났다.
o 해수온 상승에 대한 생태계/생물 영향 증거 사례는 2010 년 제주 서귀포 연안에 약 4년생 (2007 년 여름부터 정착)의 열대 흑진주 조개(유전자 비교 결과 남서태평양 마이크로네시아 서식종과 동일종으로 동정됨)가 서식히고 있음을 확인하였으며 2000넌 이후 제주연안 아열대 거품 돌산호의 급변식으로 인한 기존 부착생물 서식지 급감을 확인하였다.
O 최근 10년간 동중국해에서의 일차생산력 감소 및 일차생산자인 미세조류의 군집구성변화(소형미세조류→극미소미세조류)가 진행되고 있음을 확인하였다. 더불어 동물플랑크톤의 경우는 개체수 및 생체량은 감소하는 경향을 보인 반면 난류성 소형 요각류 (oncaeids와 corycaeids) 의 출현 빈도 풍도 및 다양도는 증가하였고 유해 생물(해파리류)의 유입도 급증하였다.
O 연안역 해저 퇴적물의 산성화가 생태계에 미치는 영향에 대한 생물반응실험 결과 요각류의 난 부화율은 감소하고 석회질 와편모조류의 휴면포자에 형태적 변이가 발생하는 것을 확인히였다.
O 해양생물반응 연구최적방법론 제시를 위한 연구를 수행하였다.
O 모형를 이용한 기후변화-저차영양단계- 상위포식자 관계를 상향 혹은 하향조절 방식으토 재현 해석하여 장기적 생태계 변화를 예측하였다.

Abstract ▼

IV. Results
1. Long-term variation of the South Sea of Korea and the East China Sea
A. Variation of water temperature in the East China Sea
Long-term variability of sea surface temperature in the East China Sea is reviewed. It is generally shown that sea surface temperature is increasing e

IV. Results
1. Long-term variation of the South Sea of Korea and the East China Sea
A. Variation of water temperature in the East China Sea
Long-term variability of sea surface temperature in the East China Sea is reviewed. It is generally shown that sea surface temperature is increasing especially in recent years with the rate of increase about 0.03 ℃/year. Other meaningful results presented in the literatures indicate that differences in water properties between layers upper and lower than the thermocline in summer show increasing trends both in temperature and salinity, suggesting the stratification has intensified. As a mechanism by which to evaluate the wintertime warming trend in the region, the weakening of wind strength, which is related to the variation of sea level pressure and atmospheric circulation in the western North Pacific and northern Asian continent, is suggested in most related studies.
B. Spatio-temporal variation of water temperature in the South Sea of Korea
In order to assess the impact of climate change on the marine ecosystem, variation pattern of seawater temperature should be extracted quantitatively. For quantifying the variation pattern of seawater temperature, horizontal, vertical and three-dimensional spatial approach method was attempted. Horizontal approach, spatio-temporal variation pattern of sea surface temperature were understood using regression analysis and spatial statistical. And vertical approach, characteristics of spatio-temporal variation pattern of representing the vertical temperature profile such as mixed layer depth, maximum temperature gradient and thermocline thickness were studied. In addition three-dimensional approach, spatio-temporal variation pattern of volume and centroid for 3D seawater temperature model were analyzed.
C. Water Property Variations in the Korea Strait
Seasonal to inter-annual variations of water properties in the western channel of the Korea Strait are investigated using quasi-monthly hydrographic observations collected during 2006−2010. At the upper layer, temperature increases from March and reaches a maximum in August, while salinity decreases during the same period. Near-bottom water shows low temperatures during late winter and fall with a minimum peak in September. Korea Strait Bottom Cold Water produces thick layers in 2006 and 2010, while it is observed very near the bottom with relatively high temperature in 2008 and 2009.
D. Monitoring of marine environment using satellites
- The annual mean SST over 26-year (1985-2010) is increased with 0.2-1.0 ℃ (0.025℃ per year). The spatial variation of SST in the China coast and the south part of Jeju Island is relatively more increased rather than in the area effected by Kuroshio current. The annual mean chlorophyll concentration over 13-year (1998-2010) is decreased with ~0.3 mg/㎥ (0.02 mg/㎥ per year). The spatial variation of chlorophyll shows that chlorophyll concentration of the most study area decreased excepted the south of the Yellow Sea. In the spatial variation of phytoplankton functional group, the linear trend of micro-and nano-size plankton is decreased, that of pico-size plankton is increased in the study area.
- satellite-derived chlorophyll data are used to investigate the seasonal difference in linear trend. The linear trend analysis of chlorophyll data reveals that during recent 15 years, spring (Mar.-May) bloom was enhanced in most of the study area, whilesummer (Jun.-Aug.) and fall (Sep.-Nov.) blooms were weakened. The increased spring chlorophyll was associated with strengthened winter (Dec.-Feb.) wind that probably provided more nutrient into the upper ocean from the deep. The causes of decreased summer chlorophyll was uncertain, but seemed to be related with the nutrient limitation. The decreased fall chlorophyll was associated with weakened wind that trends to entrain less nutrient into the upper ocean from the deep.
E. Long-term variation of mesozooplankton
Mesozooplankton data from the 314-line of NFRDI from 1979 to 2009 in the northern East China Sea show that wet weight of mesozooplankton increased after reduction in freshwater discharge from the Changjiang River since 2005, but abundance of copepods, chaetognaths, amphipods, and krill sharply decreased. The increase of mesozooplankton biomass is probably attributed to an increase of small, gelatinous zooplankton together with an recent increase in sea surface temperature and possibly over-fishing. It is not clear whether the gelatinous zooplanktion grazed the crustacean mesozooplankton or the gelatinous zooplankton win the food competition with the crustacean components.
2. Field observation of the marine environments/ecosystems on the South Sea of Korea and the East China Sea with the climate/environmental changes
A. East China Sea
- In the East Chin Sea (ECS), bacterial production showed a tendency to be regulated by water temperature and primary production from July 2006 to September 2011. Furthermore, the ratios of bacterial to primary productions also showed a positive correlation with surface water temperature, indicating that increase of water temperature might result in increase of bacterial production and carbon flow via bacteria and consequently, changes of foodweb structure in the ECS.
- Seasonal and annual variations of total biomass and size-fractionated biomass of mesozooplankton from 2004 to 2011 in the northern East China Sea were studied. Total biomass of mesozooplankton was the highest in spring, followed by fall, ummer, and winter. There was not considerable changes in seasonal and annual variations of composition of the size-fractionated biomass of mesozooplankton. The mesozooplankton size groups of <1mm averaged 47% of total biomass, including most of small adult copepods and copepodites such as Paracalanus and Otihona. The biomass of size groups of <1mm increased significantly with increasing chlorophyll concentration. If abundance of the small sized copepods having omnivorous feeding habits increase, possibly due to water temperature increase and eutrophication, the microbial food chain may be intensified than the classical food chain.
- Oncaeids and corycaeids occurred in February 2009, but warm-water species was spread through west to east of Jeju , which showed Kuroshio Branch Current was going westward of Jeju as well as typical flow of southeast of Jeju . The abundance of warm-water species in April of 2004, 2008, 2010, an 2011 far increased, as compared to that of Feb, and coastal- and cold-water species, Corycaeus affinis was very abundant as well as the most dominant species in April 2004. Distribution patterns of warm-water species occurred in April was similar to that of February. In July 2007, C. affinis and the copepodites were most abundant and were distributed only in southeast of Jeju representing distinct separation from occurrence areas of warm-water species. In Autumn (October and November) warm-water species occurred in all study areas, while C. affinis restrictedly occurred in southwest to west of Jeju , showing very little abundance.
B. South Sea of Korea
- Winter phytoplankton blooms associated with rising seawater temperature due to global warming may induce the occurrence of hypoxia and its range expansion during summer. Ocean acidification caused by the hypoxia could affect nutrient ratios in the seawater. Nutrient ratios have been known to affect the succession of phytoplankton community structure. The environmental conditions in the western channel of Korea Strait seemed to be determined by the origin of the Tsushima Warm Current (TWC) and the relative seasonal strength of the cold bottom water masses of the Korea Strait, which could be related to climate change. Therefore, the plankton ecosystem of the study areas could be related with the climate changes. Optical method is employed to monitor long term change of plankton ecosystem induced by climate changes. However, the current technology using buoy and satellite is adequate to understand the change of nutrient ratios and the succession of plankton community structure in the present.
- Oncaeids and Corycaeids collected from SJ and KS were also consisted of most warm-water species which is affected by Kuroshio Branch Current. The abundance f warm-water species gradually increased from September to November/December, in contrast, the individual number decreased from January and represented very little abundance in the later (from February to August). In autumn 2012 the abundance of warm-water species was notably low compared to same period of 2012 representing about 2℃ lower temperature than in 2011. The result showed the warm-water species was very sensitive to temperature of sea surface water. In particular, copeodites and relatively small body sized species (less than 1mm) were much closely related to sea surface temperature and flow of warm current.
- When zooplanktons were collected from SJ and KS by using each different mesh sized net (100㎛ and 200㎛), the abundance and species composition differed, respectively. To understand monthly/seasonal abundance and species composition, itis suggested that 100㎛ mesh sized net are appropriate for small sized species of less than 1mm, while 200㎛ mesh sized net for the larger sized species (more than 1mm) and species carrying egg-sag.
C. Monitoring of marine environments using buoy observations
- Time series of current data observed from the moored buoy show that the vertical velocity structure is barotropic in winter but it is baroclinic with strong southward flow in the lower layer in summer. The summertime bottom counter current may be related to the appearance of cold water in the lower layer.
- The pCO₂ values measured in the southeast coast of the Jeju Island are lower than the atmospheric pCO₂, implying the adsorption of the atmospheric pCO₂ into the ocean
- In Jeju , aragonite saturation states ranged from 1.42 to 2.82, indicating that the surface waters are oversaturated with respect to aragonite. But Aragonite saturation states did not show the distinct seasonal variation.
- The sensors of salinity, DO, chlorophyll-a are significantly affected by the biofouling, and thereby, it is required to clean up these sensors by 15 day interval for the accurate measurements.
- The chlorophyll sensor is also affected by the large difference of the fluorescence adsorption between day and night, and thus, its correction is required.
- Total biomass and size-fractionated biomass of mesozooplankton at three stations in the southeastern coast of Jeju Island were bi-weekly monitored. Total biomass of mesozooplankton were higher at offshore stations. There was inter-annual variations in total biomass of mesozooplankton, but the biomass increased with increasing water temperature. Total and size-fractionated biomass of mesozooplankton were positively correlated to both water temperature of 5m and 10m depth, but no correlation to chlorophyll-a concentration. Mesozooplankton size group of 1.0∼2.0mm dominated in mesozooplankton biomass at the offshore stations. Composition of the mesozooplankton size group of <1mm ranged from 27 to 45% with the highest at the onshore station. At the offshore stations, strongly affected by the Tsushima Warm Current (TWC), biomass of the size group of 1.0∼2.0mm dominated in the mesozooplankton biomss in spring 2012, but biomass of the size group of >5mm including salps dominated. Seasonal and inter-annual variation of the composition of gelatinous zooplankton might be changed by the seasonal variation in origin of the TWC.
3. Testing biological responses and potential indicators with climate environmental factors (ocean warming and acidification)
A. Biological responses with climate environmental factors
- Temperature has more significant impacts on the phytoplankton growth than acidification and the response of phytoplankton varies from species to species. In particular, decreased polyunsaturated fatty acids with increasing water temperature might decrease the energy transfer to high tropic grazers. Our results suggest that ocean warming and acidification in the future marine ecosystem induce the change of physiology and growth of phytoplankton, which will have significant impacts on the marine ecosystem function and structure.
- The naked-type cysts of dinoflagellates (S. trochoidea), causing the acidic environment of sediments, showed low viability. In situ hatching rate of copepods (A. erythraea) was significantly lower in the seabed of hypoxic condition than normal condition. The results suggest that the expansion of the seabed acidification by summer hypoxia may have important repercussions on population and community dynamics in coastal systems.
B. Testing potential indicators of climate change
- During cold seasons from December to April, Prochlorococcus were narrowly found only in the eastern waters of Cheju island. Conversely, in summer and autumn, Prochlorococcus showed an extended distribution to the western part of the study rea, with higher relative contribution to picocyanobacterial community. These results suggest that spatial distribution of Prochlorococcus would be seasonally different and that this seasonal variability would be related with the intensity and movement of Kuroshio Current. Due to global warming, it is expected that transport of Kuroshio Currnet to the marginal seas would increase in the future. Long-term monitoring of distribution of Prochlorococcus, as a indicating species of warm and oligotrophic water, could be helpful to understand change of current systems, especially Kuroshio Current, in marginal seas adjacent to Korea by climate change.
- This present study constructed a inventory list of emerging diatom species distributed in the tropical/subtropical warm waters and the Kuroshio Current to ascertain warm-water halophilic inidicator diatom species moving in the marine ecosystem of the Korea Peninsular via the warm water currents. Also, by analyzing the seasonal distribution of diatoms from the East China Sea and the South Sea, 35 indicator diatoms were grouped to have potential to be distributed in the marine environment maintaining the characteristics of Tsushima Current. Also, the study discussed one of methods to discern the influence of climate change and the extent of its applicability.
- We investigated the temporal distribution of species of the hyaline tintinnid Helicostomella subulata (Ciliophora, Tintinnina), which were collected the south coast of Korea. Two forms, a long form and a short form, were discovered. The long form was found in cold waters in February and March whereas the short form occurred in warm waters from June to October. Thus, two forms of H. subulata were seasonally isolated. On the basis of genetic studies, two forms are considered two morpho-species.
- The skeletal growth analysis based upon the soft X-ray and Sr/Ca ratio indicated that the oldest colonies of A. japonica analysis in this study was 12.4 years old and the most abundant age-group of A. japonica was 3-6 years old. The skeletal growth rate of A. japonica was determined to be 4.7 mm/yr, suggesting that A. japonica grow slow like other high latitude corals. And the annual recruitment rate of A. japonica population is estimated to be 4.1 colonies/㎡/yr. These results indicated that the expansion of A. japonica in Jeju Island is not transient but is continuously increasing, possibly due to the increased water temperatures caused by climate change.
- The assemblages of mollusks associated with A. japonica have been identified as 26 species of bivalves and 17 species of gastropods. It was noticeable that the bivalve species dominated in areas where A. japonica has proliferated, while there were more gastropod species in the control area where no A. japonica are present. It was assumed that A. japonica provides suitable habitats for bivalve species, since most of the fauna associated with this coral species are sessile, byssally attached, or encrusting species.
- Black-lip pearl oyster collected from Beom-som in Jeju was 3.5 year-old which was settled in the summer season in 2007. Mother-pearl oyster would be originated from the population of tropical area with Okinawa archipelagic areas considered by the duration from fertilization to spat development for about 15 days. In this study, we suggested that the chemical proxies (δ¹⁸O and δ¹³C) from the shell of marine invertebrate was effectual methodology to detect of range shifts and/or expansions from tropical to temperate areas.
4. Prediction of the climate/environmental changes based on physical-ecological modeling programs
A. Assessment of changes in biogeochemistry over the South Sea and East China Sea during the 21st century using an Earth System model
Using results from an Earth System model, we investigated change in primary production and the distribution of partial pressure of CO2 (pCO₂) in the East China Sea, under a global warming scenario. In this area pCO₂ shows minimum along the edge of the continental break along the path of the Taiwan-Tsushima Current System. Apparently modelled chlorophyll is also great along the current but the maximum of the chlorophyll and the minimum of pCO₂ do not coincide suggesting that the primary production is not the main cause of the pCO₂ minimum. As global warming progresses, the vertical stratification of water becomes stronger, and nutrient supply from the lower part to the upper part is reduced. Consequently, so is the primary production. In addition to the warming trend, there is strong decadal to interdecadal scale variability.
B. Prediction of marine ecosystem change due to climate change using a trophic flow model (EwE)
- Food web dynamics in the Sinjido marine ecosystem was predicted with EwE, a trophic flow model, under various scenarios of primary productivity due to ocean warming and ocean acidification during the period between 2020 and 2100. The model results show that total biomass of invertebrate and fish groups decreases 5%, 11∼28% and 14∼27%, respectively, depending on primary productivity, ocean acidification and combined effects. In particular blenny group shows zero biomass at 2080. Zooplankton group shows sudden increase at the same time and reaches finally twice the baseline at 2100. On the other hand, ecosystem attributes of mean trophic level of the ecosystem, Shannon's H and Kempton's Q indexes show similar reduction pattern with biomass change, indicating that total biomass, biodiversity and evenness shrink dynamically by impacts of climate change.
- Gwangyang bay, located in the southern coast of Korea has experienced environmental impacts of a rise in water temperature, reclamation and dredging projects, pollutant release and a decline in river runoff. In this study a trophic flow model, EwE, is applied to assess how water temperature rise and reclamation perturbs the bay ecosystem for 30 years in a quantitative manner. The modelshows shrinks of 4, 22, 35%, respectively, for temperature, dredging and both effects. The highly reduced groups are bivalvia 90%, goby 53%, white croaker 36%, conger 25% and red stingray 30%, while least ones are sea bass 8%, pelagic fish 6% and anchovy 3%.
- To predict and understand ecosystem dynamics in the southern waters of Korea, Ecopath with Ecosim (EwE) model was used under climate and fishery management scenarios. Climate change-induced water temperature scenario was given 10% reduction for 100 years based on NOAA Geophysical Fluid Dynamic Laboratory (GFDL) model experiments under IPCC A1B scenario. Three fishery management scenarios were given equal, double, and half the level of efforts averaged over last 10 years. The model showed that biomass changes induced by only temperature occurred in fishes of 13.7, invertebrates of 6.4 and total of 8.4%. Half catch resulted in increased biomasses of 13, 2, 5%, respectively, for fishes, invertebrates and total groups, while double catch showed decreased biomasses of 7, 5, 3%, respectively.
- Small pelagic fish, anchovy, shows about 47% of total catch in the Southern waters of Korea. They feed on zooplankton and link low and high trophic levels. In this tudy a simple food-web including plankton-small pelagic fish-predator is constructed and simulated by EwE model using top-down/bottom-up controls. Climate induced impacts are represented in forcing functions of biomass. Phytoplankton is given 10% of reduction, based on NOAA GFDL model. While other groups are given sine curves representing fluctuating of biomass in ±50% of their initial values. When phytoplankton is declined, predator's decline rate is calculated higher than that of phytoplankton. When zooplankton is fluctuated, anchovy and top predator show, respectively, the range of 60∼-47% and 35∼-33%, yielding direct proportion to zooplankton. While they show inverse proportion to other groups due to predation pressure. Impacts on anchovy are higher in bottom up control than in top down control.
- Case studies concerned with EwE application to climate change are scanned and reviews on the model limit and future implementation are described. The EwE has limited number of basic data for model setup including B, P/B, Q/B, fishery, EE and DC. Impacts on marine organisms by temperature and pH can be coped with in the model only by forcing function of B and P/B. B and P/B are time variables, while only primary producer has a time and space variable of P/B. Meanwhile, the model has space and time scales of ten's to hundred's ㎢ and year base. In general, prior to long term prediction, understanding the status of art of the study ecosystem is required. In the Southern waters of Korea, small pelagic fish of anchovy is important in terms of their catch and role in the trophic network. Thus, integrated investigation on the physical, chemical and biological aspects of the anchovy transport, feeding and growing will help figure out trophic flow in the network and future forecast. On the other hand, the EwE coupled ith a lower trophic model (ICM) can be a useful tool to represent and predict climate change induced impacts on ecosystem, since temperature and pH can be dealt with in time and space variables.
C. Prediction of the spawning ground of Todarodes pacificus under climate change
To predict the spawning ground of Todarodes pacificus under future climate conditions, we simulated the present and future ocean circulations, using an East Asia regional ocean model (Modular Ocean Model, MOM version3), projected by twodifferent global climate models (MPI_echam5, MIROC_hire), under an IPCC SRES A1B emission scenario. Mean climate states for 1990-1999 and 2030-2039 from 20th and 21th Century Climate Change model simulation (from the IPCC 4th Assessment Report) were used as surface conditions for simulations, and we examined changes in spawning ground between the 1990s and 2030s. The results revealed that the distribution of spawning ground in the 2030s in both climate models shifted northward in the East China Sea and East Sea, for both autumn and winter populations, compared to that of the 1990s. Also, the spawning area(with1/6° x 1/6° grid) in the 2030s of the autumn and winter populations will decline by 11.6% (MPI_echam5) to 30.8% (MIROC_hires) and 3.0% (MPI_echam5) to 18.2% (MIROC_hires), respectively, from those of the 1990s.