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Kafe 바로가기주관연구기관 | 한국해양과학기술원 Korea Institute of Ocean Science & Technology |
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연구책임자 | 강성호 |
참여연구자 | 김성중 , 김태완 , 김현철 , 남승일 , 박용철 , 신형철 , 양은진 , 유규철 , 이상훈 , 이원상 , 이태식 , 진영근 , 최문영 , 홍종국 , 황청연 , 권현정 , 김수관 , 김형준 , 나형술 , 민준오 , 서나리 , 윤숙영 , 전미사 , 주형민 , 하선용 , 김백민 , 김주홍 , 박상종 , 박지수 , 이춘기 , 정진영 , 김영균 , 오진아 , 최학겸 , 조경호 , 강승구 , 권영신 , 김동엽 , 김지훈 , 백동영 , 양희원 , 에릭 포트빈 , 원은영 , 이임교 , 이제인 , 이지란 , 정웅식 , 현창욱 , 김소영 , 박숭현 , 박태윤 , 백종민 , 유인성 , 이미정 , 지준화 , 최은정 , 홍상훈 , 고은호 , 박기홍 , 박정원 , 박호준 , 윤수정 , 이대혁 , 이영주 , 정재호 , 최연진 , 안인영 , 한향선 , 문종국 , 서소라 , 서승석 , 송철우 , 양규리 , 유현수 , 이수봉 , 정소망 , 최영석 , 허낙원 |
보고서유형 | 최종보고서 |
발행국가 | 대한민국 |
언어 | 한국어 |
발행년월 | 2016-08 |
과제시작연도 | 2015 |
주관부처 | 해양수산부 Ministry of Oceans and Fisheries |
과제관리전문기관 | 한국해양과학기술진흥원 Korea Institute of Marine Science & Technology promotion |
등록번호 | TRKO201800002336 |
과제고유번호 | 1525004823 |
사업명 | 극지및대양과학연구 |
DB 구축일자 | 2018-03-24 |
키워드 | 북극.남극.쇄빙연구선 아라온.양극해 급격환경변화.양극 해양환경 공간정보도.Arctic Ocean.Antarctic Ocean.IBRV ARAON.Environment in Rapid Transition.Survey and Mapping of Bi-polar Ocean. |
DOI | https://doi.org/10.23000/TRKO201800002336 |
○ 북극 및 남극해 결빙해역 현장조사 수행
- 북극 척치해, 동시베리아해, 베링해, 보포트해에서 총 4회의 종합해양환경 현장조사 수행
- 남극 로스해에서 총 2회의 종합해양환경 현장조사 수행
○ 양극해 환경변화 양상을 이해하기 위한 종합환경연구 수행
- 해빙-해양-해저 분야의 종합환경연구 수행
- 연구분야 : 해빙변화 모니터링, 해빙-해양 접합 모델, 해양 수리물리적 특성, 수층 내 생지화학 특성, 해양생태계 특성, 해저지형, 천부 해저지층, 심부 탄성파, 해양퇴적물, 해양지열 특성, 지자기 특성
○
○ 북극 및 남극해 결빙해역 현장조사 수행
- 북극 척치해, 동시베리아해, 베링해, 보포트해에서 총 4회의 종합해양환경 현장조사 수행
- 남극 로스해에서 총 2회의 종합해양환경 현장조사 수행
○ 양극해 환경변화 양상을 이해하기 위한 종합환경연구 수행
- 해빙-해양-해저 분야의 종합환경연구 수행
- 연구분야 : 해빙변화 모니터링, 해빙-해양 접합 모델, 해양 수리물리적 특성, 수층 내 생지화학 특성, 해양생태계 특성, 해저지형, 천부 해저지층, 심부 탄성파, 해양퇴적물, 해양지열 특성, 지자기 특성
○ 북극해 및 남극해 해양환경 공간정보도 작성
- 5년간 25개 분야의 해양환경 공간정보도 작성
○ 양극해 해양환경 공간정보 활용시스템(p-WebGIS) 구축
- 획득한 데이터를 통하여 웹기반 공간정보 활용시스템 구축 및 운용
○ 우리나라의 양극해 정책 추진전략을 위한 산업정책 연구 수행
(출처 : 보고서 요약서 5p)
Ⅳ. Results and Discussion
1. Marine environmental survey
1.1. Arctic Ocean
A. 1st Arctic survey
· Cruise name : ARA03B
· Research period : Aug. 1st ~ Sep. 10th, 2012
· Research area : Chukchi Sea 1-1
· No. of station : 44 stations
· No. of par
Ⅳ. Results and Discussion
1. Marine environmental survey
1.1. Arctic Ocean
A. 1st Arctic survey
· Cruise name : ARA03B
· Research period : Aug. 1st ~ Sep. 10th, 2012
· Research area : Chukchi Sea 1-1
· No. of station : 44 stations
· No. of participants : 53 people
B. 2nd Arctic survey
· Cruise name : ARA04B and ARA04C
· Research period : Aug. 21st ~ Sep. 5th, 2012 and Sep. 6th ~ 24th, 2013
· Research area : Chukchi Sea 1-2, Beaufort Sea 1-1
· No. of station : 14 stations
· No. of participants : 43 people
C. 3rd Arctic survey
· Cruise name : ARA05B, ARA05C
· Research period : Jul. 30th ~ Aug. 25th, 2012 and Aug. 26th ~ Sep. 19th, 2014
· Research area : Chukchi Sea 1-3, East Siberian Sea 1-1, Bering Sea 1-1, Beaufort Sea 1-2
· No. of station : 32 stations
· No. of participants : 54 people
D. 4th Arctic survey
· Cruise name : ARA06B
· Research period : Aug. 1stst ~ 22nd, 2015
· Research area : Chukchi Sea 1-4, East Siberian Sea 1-2, Bering Sea 1-2
· No. of station : 42 stations
· No. of participants : 43 people
1.2. Antarctic Ocean
A. 1st Antarctic survey
· Cruise name : ANA03B
· Research period : Feb. 8th ~ 23rd and 25th ~ 28th, 2013
· Research area : Ross Sea 1-1
· No. of station : 13 stations
· No. of participants : 20 people
A. 2nd Antarctic survey
· Cruise name : ANA05B
· Research period : Jan. 9th ~ Feb. 18th, 2015
· Research area : Ross Sea 1-2
· No. of station : 14 stations
· No. of participants : 8 people
2. Research of sea ice characterization
2.1. Monitoring the Arctic sea ice through integrated modeling of multi-sensor data
A. Development of the estimation of sea ice freeboard and thickness using CryoSat-2 data
(1) A total of 5 variables including Stack Standard Deviation (SSD), Stack Skewness, Stack Kurtosis, Pulse Peakiness, and Backscatter sigma-0 from CryoSat-2 were used to successfully classify lead, sea ice, and ocean. Then sea ice thickness was estimated using the classified leads in March and April between 2011 and 2014 and May to August between 2013 and 2015.
B. The empirical prediction of sea ice concentration distribution
(1) Sea ice concentration in April through September 2008 was estimated using sea ice albedo and relative vorticity at 850 hPa, which resulted in R2 ~ 0.7 and relative RMSE of 6 %.
C. Monitoring of melts ponds using multi-sensor satellite data fusion
(1) TerraSAR-x and airborne SAR (nanoSAR) data were used to identify the spatial distribution of melt ponds
2.2. Detection of small-scale deformation of an Artic sea ice floe by GPS-equipped buoys
A. Characteristics of small-scale (less than km scale) deformation
- Small-scale (~100-200 m) deformation of an Arctic sea ice floe were detected from multiple GPS-equipped buoys that were deployed on the same ice floe. The deformation events were of limited duratio, each lasting less than a day. The strain rate during the deformation, of the order of 10-5 s-1, is about three orders of magnitude larger than previous estimates for brittle fracturing for cracks of about 100 m in length.
- Ductile-to-brittle strain rate transition quickly increases when the length scale become smaller than 100 m. This demonstrates that statistics of cracks/leads is important to understand the brittle failure of sea ice.
- On the 2 day time scale, the strain rate became too small and none of the deformation events could be detected. Satellite data with longer time scales may significantly underestimate the amount of intermittent, small-scale brittle failure of total deformation.
- The large-scale wind stress can have on small-scale deformation, but the impact of large-scale wind stress is also dependent on the poperties of sea ice as well as on the spatial and temporal evolution of the underlying forces that influence the fracturing process.
2.3. Set up of Arctic ice-ocean coupled model
A. Arctic sea ice-ocean coupled model
- ROMS (Regional Ocean Modeling System, 3.4 version)
- 200×200 (Orthogonal curvilinear coordinate, 23~30 km), 50 s-coordinate levels
- Building up a multiple process model including four major tidal forcings (M2, S2, K1, O1)
B. Model validation
- Simulating sea ice distribution and oceanic circulation of the Arctic Ocean by a hindcast model run
- Validation of model results comparing with observations and advanced overseas modeling results
C. Effect of tides on the sea ice distribution in the Arctic Ocean
- With tides, increasing the sea ice volume of about 8.5% in the Baffin Bay, while decreasing it of about 17.8% in the Canadian Arctic Archipelago
- The decrease of sea ice volume due to the enhanced vertical mixing by tides and thereby suppression of ice formation in winter
- The increase of sea ice volume due to the convergence of sea ice, which is driven by tidal residual currents
- Checking the inability of a tidal mixing parameterization in reproducing the increase of sea ice volume by tidal residual currents
D. Optimizing the Arctic sea ice-ocean coupled model
- Optimizing model with a Green’s function approach to improve the skill of sea ice prediction
- Reducing 10~20% of model errors in sea ice concentration and extent, and more than 80% of errors in sea ice thickness by the optimization
3. Research of marine environmental characterization and carbon cycle
3.1. Understanding of Hydrophysical Variability using Polar Field Observations
A. Distributions of the Pacific-origin Waters in the Arctic Ocean
(1) Generally Pacific Winter Water (PWW) flows northward through the Herold Canyon and then there are two types of its pathways into the Arctic Ocean: one turns to the east toward the Canada Basin (2002~2007, 2009~2013) and the other moves directly northward (2008, 2014).
(2) The Pacific Summer Water (PSW) was mainly distributed in the Beaufort Sea and tends to extend to the west. It showed weak extension in 2012 but has gradually extended to the west since 2013.
B. Changing of Water Properties and Circulation in the Arctic
(1) Horizontal distributions of heat content estimated in upper layer (20~150m) were very similar to those of PSW. This implies that PSW transports most of heat in the water from the Pacific Ocean into the Arctic Ocean.
(2) Horizontal distributions of freshwater content were relatively similar to those of heat content. This implies that heat content in upper layer plays a role in melting sea ice and then melt water tends to decrease salinity at the surface layer.
(3) According to the distributions of dynamic height (DH) from 2011 to 2014, the Beaufort Gyre was the strongest in 2012 and DH on the western part was larger than that on the eastern part showing an asymetric structure as Western Boundary Current. The center of the Beaufort Gyre moved to the east in 2014 implying that interannual variation in circulation could occur.
C. Relationship between ocean and sea ice variations
(1) PSW exists from 30 to 80 m depth whereas PWW exists 150~200 m depth.
(2) We compared sea ice extent (SIE) anomaly and sea temperature and salinity anomalies in order to investigate relationship between ocean and sea ice variations. Temperature anomaly of PSW was negatively correlated with SIE anomaly but salinity anomaly of surface mixed layer (SML) was positively correlated with SIE anomaly. This implies that warm PSW plays an important role in melting sea ice and melt water plays a significant role in decreasing salinity in SML.
3.2. Dissolved inorganic carbon system and surface pCO2
A. Saturation anomaly of surface CO2 concentration
- The entire survey area absorbed the atmospheric CO2 during the research period. Dividing the area into the Arctic Basin (AB), the Chukchi Sea (CS), and the Beaufort Sea (BS), CS recorded the lowest saturation anomaly of 20 – 50 % on annual average, AB was the next as 10 – 20 %, and BS ranked the lowest of 5 – 10 %.
- Temporal variation in saturation anomaly does not reveal a specific trend, although AB indicated the lowest of 5 % in 2012 when the sea-ice extent in the Arctic Ocean recorded lowest.
B. Variation of CO2 sink strength
- Sink strength or absorption capacity can be a function of saturation anomaly and wind speed. During the research period, the atmospheric CO2 over CS was taken up by 10 – 20 mmol/m2/day, by 4 – 8 mmol/m2/day over AB, and by 5 – 8 mmol/m2/day over BS. This indicates that CS played a role of the most powerful sink in the research area.
- Temporal variation of CO2 sink does not show a specific trend. However, it looks following the wind speed in AB, suggesting kinetic force could be one of important parameters determining the CO2 sink
C. Inorganic carbon system in the water column
- We used the dissolved inorganic carbon (DIC) and total alkalinity (TA) as key parameters determining the inorganic carbon system in the Arctic Ocean. These two concentrations rapidly decreased in the surface, then gradually in the mid-depth, and stayed nearly constant in depth. However, DIC slightly decreased in 200 – 300 m deep after reaching the highest value.
- Following the conventional water masses in the Arctic Ocean, we divided the vertical structure into 6 distinct water masses such as the Surface Mixed Layer Water (SMLW), the Pacific Summer Water (PSW), the Pacific Winter Water (PWW), the Lower Haline Water (LHW), the Atlantic Water (AW), and the Arctic Ocean Deep Water (AODW). Temporal variation of DIC and TA shows convex parabola shape while the water masses in mid-depth (PSW, PWW, LHW, AW) looks concave. DIC in AODW did not change significantly while TA varies in a bulging shape.
3.3. Research of relationship between environmental factors and plankton ecosystem
3.3.1. Characteristics of nutrients distributions in the Polar Ocean
A. Advective nutrient inputs through the Bering Strait
- There is an east-west gradient in water-mass properties across the Bering Strait, with the highest nutrient concentrations, highest salinities, and lowest temperatures generally occurring in the Anadyr Water in the west; and the lowest nutrient values, and lowest salinities and highest temperatures tending to occur in Alaska Coastal Water in eastern Bering Strait
- Phosphate concentration ranged from 0.25~0.75 μmol L-1 in surface water where the influence of Alaska Coastal Water is dominant. On the other hand, nitrate concentration was below dectection limit, suggesting that nitrogen is depleted in Pacific influenced waters, and that nitrogen is a limiting factor of primary production in the Arctic Ocean
- Ammonium concentration, which is produced by decomposition of organic matter
deposited at the bottom of the shelf, ranged from 1~6 μmol L-1 in the continental shelf where the influence of Anadyr Water is dominant. This result suggests that the decomposition of particulate organic matter by microbial activities is active in this region, and that high nutrient concentrations can be derived from the remineralization of particulate organic matter and the influence of Anadyr Water
B. Vertical distribution of nutrients in the Chukchi Sea
- The Pacific-origin water can be classified into two types based on seasonal modifications on the Chukchi Sea shelf, i.e., Pacific Summer Water and Pacific Winter Water, which compose the upper halocline of the western Arctic Ocean (depth < ~200 m)
- Pacific Summer Water and Pacific Winter Water are characterized by a temperature maximum (salinity = 31-32; depth < ~ 80 m) and temperature minimum (S ~ 33; depth = 100-150 m), respectively
- Although nitrogen was depleted in surface water, 7~10 μmol L-1 of nitrate and 2~3 μmol L-1 of ammonium were observed at 10-50 m depth. In addition, 4~9 mg m-3 of chlorophyll a concentration was also observed at the same depth, showing that primary production occurred in the Chukchi shelf
- Chlorophyll a concentration sharply decreased from the shelf break to the Canada Basin. Riverine input increases stratification, which reduces inputs of nutrients from deeper layer into the photic zone. In addition, decrease in the availability of light by the existence of sea ice influences primary production in the Arctic Ocean. Low chlorophyll a concentration in the Canada Basin therefore is likely due to strong stratification and influence of sea ice
- Highest concentrations of nitrate were found just above the sediments of the shelf stations and in the subsurface nutrient maximum in the halocline waters at the shelf/slope break
C. Distribution of nutrients in the Ross Sea, Antarctica
- There was the difference of nutrients concentration between the eastern side and the western side of 170°E
- In the eastern side, mean concentrations of phsophate, nitrate and silicate were 1.85 ± 0.51 μmol L-1, 19.15 ± 5.23 μmol L-1 and 145.24 ± 28.4 μmol L-1, respectively
- In the western side, mean concentrations of phsophate, nitrate and silicate were 2.12 ± 0.74 μmol L-1, 21.38 ± 2.78 μmol L-1 and 152.47 ± 26.99 μmol L-1, respectively
3.3.2. Concentration distribution and fluorescence characteristics of dissolved organic
matter in the Arctic Ocean
A. Concentration distribution of dissolved organic matter in the Arctic Ocean
- Concentration of dissolved organic carbon showed lower values at stations located in the coastal Beaufort Sea and Bering strait as compared to other stations
- Concentrations of dissolved organic carbon were significantly negatively correlated with salinity at stations located in the coastal Beaufort Sea and Bering strait
B. Fluorescence characteristics of dissolved organic matter in the Arctic Ocean
- Humification index showed higher values at stations located in the coastal Beaufort Sea and Bering strait as compared to other stations
- Highly humified dissolved organic matter seems to be delivered through river inputs to the Arctic Ocean
3.3.3. Study of cold-adaptation of arctic sea ice microorganisms
A. EPS composition and characterization of sea ice microorganisms
- Exopolysaccharides of Synedropsis sp. is sulfated fucans because that is largely composed of sulfur(5.43%) and sulfuric ester(40.4%).
- Component sugar analysis and microscopic analysis show that main polysaccharides is fucose(36.2%) and rhamnose(27.9%), xylose(23.2%) and minor polysaccharides is galactose(11.2%) and glucose(1.4%).
B. Ice-binding characterization of EPS
- Ice-crystall shape of extracted EPS from the algae culture media is similar to xanthan gum and that from the bacteria culture media looks like bacteria culture media. But all EPS doesn’t show temperature history activity and ice-recrystallization inhibition activity.
- In ice absorption test, Is values of xanthan gum and EPS_S are 0.97±0.05 and 0.95±0.08. Because there is similar 1, we think that EPS doesn’t bind to ice.
C. Bioactivity of EPS
- Hydroxyl radical scavenging activity of EPS_F is similar to that other of EPSs, while DPPH radical scavenging activity is a 15-fold higher activity compared to the xanthan gum used as a control.
- EPS_F 1% showed very high survival rate (24hours; 70.66±5.4% and 48hours; 66.13±2.0%), while EPS_S and EPS_P showed 0% survival rate. These result are not as expected. Thus we concluded that EPS_S and EPS_P have antibacterial activity from the results.
3.3.4. Bacterial and viral abundances, and prokaryotic community
A. Distributions of bacterial and viral abundances
(1) Bacterial abundances showed a wide range of 0.1-35.6×105 cells ml-1 in water columns, and mostly highest in the surface or at subsurface chlorophyll-a maximum (SCM) layer
(2) Viral abundances were on average 14-fold higher than those of bacteria. A significantly positive correlation was found between bacteria and viruses, indicating that bacteria would be major hosts of viruses in the study area.
B. Prokaryotic community
(1) Pyrosequencing of 16S rRNA gene was performed for samples collected from various polar environments, including seawater, melt ponds and sea-surface microlayer. 651,848 high quality sequences were obtained and subjected to analysis
(2) In a result of prokaryotic community in melt ponds and seawater, it was notable that richness of species was positively related to salinity
(3) In a comparison of bipolar prokaryotes, it was common that Proteobacteria (Alpha- and Gammaproteobacteria) and Bacteroidetes were dominant near the surface, and Crenarcheota increased along with depth. Dominant groups of Planctomycetes and SAR406 were uniquely found in Chukchi Sea and Ross Sea, respectively
3.3.5. Characteristics of phytoplankton in the Polar Ocean
A. Distribution of chlorophyll a concentration in the Chukchi and east Siberian Sea
- The depth-averaged chl-a concentrations were higher in the Bering Strait and coastal waters (> 1 ugL-1) of the Eastern Siberia than those in the Chukchi Plateau and open sea (< 1 ugL-1), indicating that the phytoplankton biomass decreased from coast to open ocean
- The phytoplankton biomass (chl-a) in the northern part of the Chukchi Sea is likely to be influenced by expansion and reduction of the sea ice
B. Relationship between phytoplankton communities and environmental factors
- Diatoms were predominant taxa in the Chukchi Sea, constituting up to 80% of total phytoplankton abundance, except in the nano- and pico-size ranges
- Nano- and pico-sized phytoplankton appeared predominant at high latitudes, whereas larger diatoms were predominant at the western and eastern boundaries of the study area
- These results imply that phytoplankton communities are likely differentiated among water bodies (e.g., Pacific Winter Water, East Siberian Water, and Northern Sea Ice Melting Water), salinities, and nutrient concentrations(especially nitrogen) in diverse arctic water masses.
C. Illustrations of Phytoplankton Diatoms in Arctic and Antarctic Oceans
- To fill knowledge gaps in the morphological understanding of phytoplankton communities in the Poalr Ocean, 118 species image analysis was performed.
3.3.6. Identifying zooplankton community structure and ecological characteristics of Arctic-Antarctic Ocean.
A. Zooplankton community structure of Arctic, Chukchi Sea and East Siberian Sea.
- In 2014, station 19 which is located norhtern-most region compared to other station, showed the lowest habitat density of 11 indiv.m-3 and station 2 marked the highest habitat density of 3,168 indiv.m-3 in 2015
- According to data collected from 2014 and 2015 (which had the most number of stations surveyed), stations which have shallower depth seem to have higher habitat density compared to stations with deeper depth
- Zooplankton species which has the highest impact on the community composition for each annual survey is Calanus glacialis
B. Zooplankton similarity analysis
- After running similarity analysis between each stations based on the habitat density, results showed that density between stations can be distinguished according to depth
- In year 2014 and 2015 the similarity of zooplankton can be grouped by north and south at latitude 76 degrees
- At stations with lower depth, some cladocera as well as larvae of brittle stars were either dominant species or occurred in large numbers, however these species appeared in small numbers or didn’t appear completely at stations with higher depth.
- In general, zooplankton of the polar region maintain low habitat density throughout the year, but its habitat density increases rapidly as population of phytoplankton rapidly grows in the summer. Station which peaked in habitat density in year 2014 and 2015 seems to show just slight difference but Chl. A was relatively high compared to other stations as well as larvae of planktonic copepods, brittle stars, barnacle and mysids also occurred in high numbers compared to other stations.
3.3.7. Zooplankton ecosystem under Arctic sea ice
A. Environmental condition of zooplankton habitats in the Canda Bsin, Arctic Ocean
- Clear daily cycle of solar radiation was observed even if the sun is visible for the full 24 hours during the midnight sun.
- Water temprature and salinity were relatively low because of surface sea ice melting during summer. Subsurface chlorophyll maximum depth was observed around 60 m within pacific summer water between 45 and 100 m.
B. High resolution vertical behaviour of zooplankton
- Acoustic method are broadly used to sensing aquatic animals, zooplankton, and physical and biological habitat characteristics.
- Collect continousely the relative abundance and the high resolution of main habitat of dominant zooplankton, Arctic copepod, from acosutic signals.-
- Arctic copepod under sea ice was mainly distirubted from 20 m to 45-m depth.
C. Zooplankton behaviour with environmetnal variables
- Vertical behaviour of Arctic copeopd, determined by acoustic backscatter was closely correlated with the daily cycle of solar radiation.
- The maximum depth of Arctic copepod during diel vertical migration was about 45 m. They prefer to remain the stable water column between 25 and 45 m where diatom was dominant in the water column.
3.3.8.Characteristics of planktonic protozoa
A. Spatial distribution of planktonic protozoa
(1) Microzooplankton composed by ciliate and Heterotrophic dinoflagellate(HDF) and ciliate significant component of microzooplankton populations.
(2) The spatial distribution of microzooplankton abundance and its composition were related to differences in phytoplankton biomass in the three water masses.
(3) Abundance of planktonic protozoa correlated well with chlorophyll - a concentration in the study area. Thus, a tight coupling between microzooplankton abundance and phytoplankton composition likely indicates that food supply is among the most important factors controlling the spatial dynamics of microzooplankton.
B. The grazing impacts of protozoa on phytoplankton
(1) The grazing impacts of protozoa on phytoplankton were substantial, accounting for an average of 73.1 of daily phytoplankton production. Protozoa gazing impacts were relative high in the Chukchi Sea which was dominant by picophytoplankton.
(2) The grazing impacts of protozoa was relative high on picophytoplankton compared to total phytoplankton production. Their hervibory may be a driving force controlling pico-phytoplankton growth in early summer in the western Arctic Sea, particularly in the Chukchi Sea.
3.3.9. Variability of remotely sensed surface chlorophyll-a in west Arctic Sea
A. Spatial and temporal distribution of chlorophyll-a
- Weak seasonality was observed from surface chlorophyll-a of recent 17-year ocean color data in west Arctic Sea except Chukchi Sea. Increasing trend of chlorophyll-a concentration was also observed in most regions during recent decade
- Surface chlorophyll concentration is relatively high in coastal regions, especially around East Siberian Sea, where riverine input is high. On the contrary, surface chlorophyll concentration is low in the Canadian Basin of the Beaufort Sea
B. Variation of sea ice and sea surface temperature
- We classified west Arctic to six regions for detailed analysis. Generally, open water duration (sea ice free season) was gradually increased. Positive relationship between open water duration and summer chlorphyll-a concentration was observed except Beaufort Inner region
- Sea surface temperature was also increased especially in the East Siberian Sea, Laptev Sea, and coastal region of Beaufort Sea. Strong positive relationship between open water duration and sea surface temperature was also observed
C. Impact of open water duration
- Increasing of surface chlorophyll-a concentration and sea surface temperature following the abrupt demise of sea ice was observed in most west Arctic, but chlorophyll concentration in the Beaufort Inner was not increased exceptionally - Besides of sea ice variation, future study should be more focussed about influence of physical factors (ex, mixed layer change) and chemical factors (ex, nutrient supply) which related with ecosystem change in west Arctic Sea
3.4. Monitoring of carbon cycles in sea-ice/marine ecosystems
3.4.1 Purpose of the study
- Monitoring of carbon cycles in sea-ice/marine ecosystems in response to sea-ice dynamics under a rapid sea-ice melting regions in the Arctic and Antarctic Oceans
3.4.2. Importance of the study
- The Arctic has important roles in changing the Earth environments, such as weather, climate, and ocean current circulation
- The changes in the Arctic could have an influence on a global scale and also it could be affected by the changes of the Earth environment
- The large change of marine environments and ecosystems in the Arctic Ocean could be anticipated by ongoing decrease of sea ice
- The Chukchi Sea is an important region as only channel transporting organic matters and water masses from the northern Pacific Ocean into the Arctic Ocean
- Because the substantial decrease of sea ice occurred especially in the western region of the Arctic Ocean, the changes of environment and productivity in the western Arctic Ocean is important for understanding marine ecosystem in the Arctic Ocean responding to the changes.
3.4.3. Methods
A. Measurements of carbon and nitrogen uptake rates by phytoplankton
- Carbon and nitrogen uptake rates were measured using a 13C-15N dual isotope tracer technique at six light depths (100, 50, 30, 12, 5, 1%)
B. Analysis of photosynthetic-end products by phytoplankton
- Proteins, carbohydrates, and lipids of phytoplankton were analyzed as following, Lowry et al. (1951) for proteins, Dubois et al. (1956) for carbohydrates, and Bligh and Dyer (1959) and Marsh and Weinstein (1966) for lipids, repsectively
3.4.4. Results and discussion
A. First year
- Averaged hourly carbon productivity by phytoplankton was 3.28 mg C m-3 h-1 (S.D.= ± 1.69 mg C m-3 h-1), whereas hourly nitrogen productivity was 7.13 mg N m-3 h-1 (S.D.= ± 7.47 mg N m-3 h-1) which was higher than the hourly carbon productivity
- Nitrogen production was similar whereas carbon production had a high interannual variation compared to previous studies
- To understand variation of primary production by environment changes in the Arctic ocean, more studies will be conducted for seasonal variation and spatial distribution of primary production
B. Second year
- The contribution of small-sized phytoplankton (< 5 μm) to the total carbon production was 32%, whereas the contribution to the total carbon biomass was 59%
- Small-sized phytoplankton had a lower primary production efficiency than relatively large-sized phytoplankton
C. Third year
- During the study period in 2009, daily nitrogen uptake rates were ranged from 6.3 to 126.1 mg N m-2 d-1 which results were lower than those reported previously in this area, and daily carbon uptake rates were relatively low with an average of 0.3 g C m-2 d-1 (S.D.= ± 0.2 g C m-2 d-1)
- The low primary production could be resulted from the decrease of chlorophyll a concentration by less widespread Anadyr Water which normally has high nutrients and phytoplankton biomass
D. Forth year
- Averaged lipid content of phytoplankton in the Chukchi Sea was 58.4% (S.D.= ± 8.2%), followed by carbohydrates (25.5 ± 7.1%) and proteins (16.1 ± 7.3%)
- The phytoplankton with higher lipid contents could provide relatively high calorific foods to upper trophic levels
E. Fifth year
- In the camp 1, averaged daily nitrogen uptake rates of melt pond, sea ice core, water column under sea ice were 0.080 mg N m-2 d-1, 0.064 mg N m-2 d-1, and 1.929 mg N m-2 d-1, respectively, and averaged daily nitrogen uptake rates in the camp 2 were 0.068 mg N m-2 d-1, 0.336 mg N m-2 d-1, and 9.351 mg N m-2 d-1, respectively
- In general, sea ice core and water column had higher NH4 concentration than NO2 NO3 concentration and melt ponds had similar concentrations of NH4 and NO2 NO3
- Averaged assimilated C/N ratio in sea ice core was highest value (10.7), whereas melt pond showed 6.1 during our study period
- The higher C/N ratio than Redfield ratio (6.6) indicate that phytoplankton undergo nitrogen limitation for their growth
4. Research of sub-marine environmental characterization
4.1. Marine Survey
- We conducted multibeam survey, SBP, multichannel seismic survey, sediment coring and heat flow measurement to investigate marine geological and geophysical characteristics.
- In the Chukchi Sea, we obtained marine geological and geophysical data from 2012 and 2015.
- In the Beaufort Sea and the Ross Sea, we acquired for four year
4.2. Seafloor mapping
A. Seafloor features in the Chukchi Sea, the Arctic Ocean
- On the sealfloor of the Chukchi Sea, plow marks generated by floating icebergs are shown in shallow waters. These marks are easily found within 500-meter water depth.
- Noticeable seafloor feature in this region is pockmarks. These are believed to be made by gas expulsion and the biggest one is more than 600 meter in diameter.
- In the Arlis plateau, mega-scale glaciation lineations are found below 1200-meter depth. It implies that this region was covered by thick ice shelf thicker than 1200 meters.
B. Seafloor features in the Beaufort Sea, the Arctic Ocean
- In the continental shelf it is relatively shallow having less than 100 meter depth.
- Plow marks by icebergs are also revealed in the continental shelf.
- Below the subsurface permafrost formed during the last glacial period is melting by the warm waters. Because of this, characteristic features such as Gary Knolls and Pinggo-like features are found.
C. Seafloor features in the Ross Sea, the Southern Ocean
- Continental shelf shows relatively deep water depth of about 400 meters.
- Plow marks by icebergs are also revealed in the continental shelf.
D. Multibeam processing technique
- We developed a method for classifying sediment characteristics using back scattering from the multibeam data.
4.3. Sub-bottom profiler survey
A. Arctic shallow sediment structure
- During 2012 ~ 2015 expedition, SBP survey was conducted between continenental shelf and slope in the Chuckchi sea and the Beaufort sea. A total 24,810 line-km of SBP data was acquired. In detail, 18,370 line-km data in the Chuckchi sea and 6,640 line-km data in the Beaufort sea was collected.
- In the continental shelf area, SBP data shows the keel mark by icebergs. In the deep area, SBP data shows the typical features of pelagic deposits with thick and well stratified.
- In the transition area between slope and basin, deposit structure of ice rafted debris and pelagic deposits is revealed.
B. Antarctic shallow sediment structure
- During the 2012-2013 ANA03B, and 2014-2015 ANA05B expedition, Antarctic SBP survey was conducted in the Ross sea continental shelf and slope. Total survey length is 14,500 line-km.
- A results of the SBP survey in the Joide Trough, continental shelf area in the Ross sea, SBP data shows the grounding-zone wedge which form trough the delivery of deforming subglacial sediments. For the Central Basin, SBP data shows the stratified sediments around 10 ~ 40 m thickness in the continental slope area. Towards the center of the basin, sediments shows lenticular body form.
4.4. Multi-channel seismic survey
A. Arctic multi-channel seismic survey
- During the 2013, 2014 expedition, Multi-channel seismic survey was conducted in the Beaufort sea Mackenzie Basin area. The seismic data consist of 16 survey lines, 516 line-km.
- As a results of seismic stratigraphic interpretation, unconformity throughout the Mackenzie Delta is assumed by regression in the glacial period on the Pleistocene. The continental shelf area is the vertical reverse fault zone, and the slope area is well-developed the folds.
- Sediment layers under the unconformity is assumed by Mackenzie Bay or Akpak on the Miocene, lower sediment is considered the Iperk sequence on the Pliocene.
B. Antarctic multi-channel seismic survey
- Multi-channel seismic survey was conducted in the Central Basin, the Ross sea, during the 2012-2013 and 2014-2015 expedition. Seismic data of 11 survey lines and 900 line-km was collected.
- As a results of seismic stratigraphic interpretation, we confirmed the progradation in the Joides Trough and vertical accretion in the Northern Basin during the period between the middle and late Miocene. During the rifting evolution process in the West Antractica, it is seems to change in the thermal subsidence basin formed by sequentially or local characteristics affected differently by the iceberg.
- From the middle Miocene to the late Pliocene, stratified sediment layers of the outer shelf in the Joides Trough and center in the Central Basin are appeared. But, after RSU2, it is seems that the sediment supply to the Central Basin was decreased due to move the center of the depositions.
4.5. Marine Sediment
A. Marine sediment coring
- In the bi-polar region, marine sediments were sampled using sediment coring and physical properties were examined.
- Sediements were recovered using gravity corer, multi-corer, box corer aboard Korean icebreaker, Araon.
- In the Chukchi sea, 6 sites were chosen as sampline sites while 12 and 5 sites in the Beaufort Sea and the Ross Sea, respectively.
- Among physical properties of sediment, density, porosity, P-wave velocity and susceptibilities were analysed. Specific properties were chosen depend on the cruises.
4.6. Analysis on marine heat flow
A. Eastern slope of the Mackenzie Trough in the Arctic Canadian Beaufort Sea
- Marine heat flow was collected in total 7 stations during the Araon’s expeditions of ARA04C in 2013 and ARA05C in 2014
- Observation in marine heat flow was carried out for the first time in this area, and its results range from –79 to 69 mW/m2 (16~69 mW/m2 when excluding negative value)
- In order to explain negative and low values of the observed heat flows, a working hypothesis where ice-bearing subsea permafrost and/or collapsed sediments can depress geothermal gradients can be established
- Long-term observation in bottom water temperature change and additional data collection are essential to depict detailed thermal structure in the trough,
B. Eastern flank of the Adare Trough in the Antarctic Ross Sea
- Marine heat flow was collected in total 3 stations during the Araon’s expedition of ANA05B in 2015
- Observation in marine heat flow was carried out fir the first time in this area, and its results range from 87~130 mW/m2
- Only based on restricted number of data points we have, it looks that observed results are rather higher than ones estimated from formation age of the trough
- Our findings can be explained by working hypotheses such as 1) occurrence of hotter-than-normal asthenosphere below the trough, 2) thermal disturbance after cessation of seafloor spreading by intrusive volcanic activities and/or fluid circulation along faults, and 3) technical error in data collection
- Dense data collection along with the NBP9702 Line 06 as a baseline is essential to depict detailed thermal structure in the trough.
4.7. Geomagnetics
A. Geomagnetics in the Arctic
- Magnetic modeling was conducted using CHAMP satellite data and surface measurements and magnetic anomaly maps of altitude of 300 km and 5 km were made.
- Satellite data show positive anomaly on the Mendeleev ridge and ver high magnetic anomaly on the Brooks ranges.
- On the Chukchi Borderlands region, low anomaly are revealed on the northern Chuchi basin and Hope basin.
- On the Canadian basin, median scale magnetic anomaly are shown on the boundary between continental and oceanic crust.
B. Analysis on the Antarctic magnetic anomaly and production of anomaly map
- We analysed magnetic anomalies in the Ross Sea region and magnetic anomaly map using CHAMP satellite data.
- The Ross Sea comprises of three major basins called Victoria basin, Central Basin, and Eastern basin. Low magnetic anomalies are revealed in the Eastern basin. Magnetic lineations are shown due to continental rift in the souther part of Victoria Basin and the Central basin.
- K-PORT project supported to produce magnetic anomaly map, ADMAP-2, by hiring Russian specialist.
- Magnetic data acquired after 2000 by many countries were collected, reprocessed and compiled.
- Final product of ADMAP-2 will be finished by the end of 2016.
C. Magnetic study using 3-component magnetic instrument aboard Araon
- We analysed 3-component magnetic data to check stability and availability.
- Compared with total magnetic data, 3-component data show relatively reliable when it was propery acuired and processed.
- We established magnetic model for Antarctic basin and present theoretical 3-component anomalies.
4.8. Geographic Information System for Marine Geophysics
A. Establish GIS for polar marine geophysics
- We established GIS system for polar marine geophysics using ArcGIS
- We constructed separated system for the Chukchi Sea, the Beaufort Sea and the Ross Sea
- Geophysical tracks, SBP images, coordinates of sites were included in the syste,
- Data acquired from other organizations were also included for the purpose of planing and analysis
4.9. Geologic structures of methane release and mud volcanoe
- In the Chukchi sea, pockmarks resulted from gas release are found frequently. Many pockmarks have large size up to 700 m in diameter.
- In the Beaufort sea, many geologic structures made by the dissociation of gas hydrates and thawing permafrost.
- In the continental margin, Pingo-like features are found frequently.
- We found a new mud volcanoe in the slope and observed gas release from a known mud volcanoe on the echogram
5. Development of Geospatial Information System (GIS) for Polar Ocean Ecosystems
5.1. Overview
A. Overview and scope of the project
- Developing a web based GIS, called p-WebGIS to share and utilize spatio-temporal variations observed in both the Arctic and Antarctic oceans
- Scope: Database construction, Web GIS development, Fieldwork support, Enviromental themetic mapping
B. Background and objectives
- Integrating and sharing field measurement data, helping field researchers via fieldwork support system, increasing scientific capabilities of accumulated data
5.2. Contents
- Searching research sites, Visualizing spatial distribution of field measurements (e.g. temperature, density, salinity, etc) and thematic maps at each station, Easy-accesing spatial-statistical graphs, Providing user friendly graphical user interface (GUI)
5.3. System operation plans
A. Operation plans
- Effectively utilizing marine environmental data collected by KOPRI via p-WebGIS and providing a sustainable web service
B. Maintenance plans
- Five maintenance rules for system and database: Preventive maintenance, Maintenance support, Defaults management, Fault recovery, Performance improvement
6. The idea of practical strategies regarding polar oceans: by analyzing policies of major countries and international institutes
- Polar oceans are the treasure house of human being and the important base for researching and preparing for rapidly progressing global environment change.
- The national profits in the Antarctic is guaranteed by the scientific research and the Arctic ocean is unique region that needs to joint research and development with other countries.
- Considering importances of the Arctic and international trend, our policy goal of the Arctic need to be 'use and conservation of Arctic as common property of human being'
- The Arctic Council has four objectives: protection of the well-being of the inhabitants of the Arctic, indigenous people and their communities; protection of the Arctic environment, health of Arctic ecosystems and maintenance of biodiversity; sustainable development of Arctic resources; economic and social development of the Arctic region.
- The Article 234 (Ice-covered Areas) of the UNCLOS provides principles on marine environmental protection and preservation applicable to the Arctic Ocean.
- International Maritime Organization Guidelines for Ships Operating in Arctic Ice-Covered Waters.
- Major regulations of the fishery management in the Arctic Ocean : UN Fish Stocks Agreement, Regulations for the Marine Environment of the Arctic Ocean.
- All activities in the Antarctica are carried out within the international framework, so called Antarctic treaty regime. At the core of such activities are scientific research and international cooperation for sustainable and peaceful use of the Antarctica and its environmental preservation. For example, to establish research station in Antarctica, and to designate Antarctic special protection zones and to undertake Antarctic research and investigation activities.
- Major nations have played key roles in international developments on Antarctica by implementing domestic system and conducting research on the issue.
- Korea should be engaged in activities of the Arctic Council. It needs to strength its cooperation with Arctic coastal nations, such as Russia, the US, Canada, Demark and Norway.
- Conditions for integrated Antarctic policies are insufficient due to the lack of coordination and cooperation system among ministries and the absence of national long-term Antarctic policies.
- Due to government-centered policy implementation private participation in Antarctic activities and policies remains low and policies for training experts are indeed insufficient.
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