Original Article
704
Kor J Fish Aquat Sci 45(6),704-715,2012 한수지 45(6), 704-715, 2012
제주도 사질 조간대 공극수중 영양염류의 시·공간적 변화
To examine temporal and spatial variation in salinity and nutrients in the shallow pore water of intertidal sandflats, we measured salinity and nutrient concentrations (dissolved inorganic nitrogen [DIN], phosphorus [DIP], and silicate [DSi]) in pore water of the intertidal zone along the coastline of Jeju Island at two and/or three month intervals from May 2009 to December 2010. Geochemical parameters (grain size, ignition loss [IL], chemical oxygen demand [COD], and acid volatile sulfur [AVS]) in sediment were also investigated. The surface sediments in intertidal sandflats of Jeju Island were mainly composed of sand, slightly gravelly sand and gravelly sand, with a range of mean grain size from 0.5 to 2.5 Ø. Concentrations of IL and COD in sediment were higher along the eastern coast, as compared to the western coast, due to differences in biogenic sediment composition. Salinity and nutrient concentrations in pore water were markedly different across time and space during rainy seasons, whereas concentrations were temporally and spatially more stable during dry seasons. These results suggest that salinity and nutrient concentrations in pore water depend on the advective flow of fresh groundwater. We also observed an imbalance of the DIN/DIP ratio in pore water due to the influence of contaminated sources of DIN. In particular, nutrient concentrations during rainy and dry seasons were characterized by high DIN/DIP ratios (mean- 127) and low DIN/DIP ratios (mean-10), respectively, relative to the Redfield ratio (16) in offshore seawater. Such an imbalance of DIN/DIP ratios in pore water can affect the coastal ecosystem and appears to cause outbreaks of benthic seaweed along the coastline of Jeju Island.
Key words: Sediment, Pore water, Nutrients, Intertidal sandflat, Juju Island
Temporal and Spatial Variation of Nutrient Concentrations in Shallow Pore Water in Intertidal Sandflats of Jeju Island
Dong-Woon Hwang
*, Hyung-Chul Kim, Jihye Park and Won-Chan Lee
Marine Environment Research Division, National Fisheries Research & Development Institute, Busan 619-705, Korea 황동운*·김형철·박지혜·이원찬
국립수산과학원 어장환경과
Article history;
Received 8 June 2012; Revised 20 November 2012; Accepted 22 November 2012
*Corresponding author: Tel: +82. 51. 720. 2532 Fax: +82. 51. 720. 2515 E-mail address: [email protected]
Kor J Fish Aquat Sci 45(6) 704-715, December 2012 http://dx.doi.org/10.5657/KFAS.2012.0704 pISSN:0374-8111, eISSN:2287-8815
ⓒ The Korean Society of Fishereis and Aquatic Science. All rights reserved
서 론
연안지역에서파도와조석은육상의지하수면(water table) 과바다의해수면(sea level) 사이의수리학적경사(hydraulic pressure gradient)를변화시키고, 이는공극수의이류적흐름 을야기한다(Shum and Sundby, 1996; Burnett et al., 2006).
공극수의유동은수평·수직방향의 3차원적인복잡한양상을 보이며주로퇴적물내에서일어나지만해수-퇴적물의경계면 을통해공극수가해양으로빠져나오기도한다. 이러한해수- 퇴적물의경계면을통해해양으로유입되는공극수의이류적
흐름을해저지하수유출(submarine groundwater discharge)이 라고하며, 이는육상의담지하수(fresh groundwater) 뿐만아 니라해저퇴적물에스며들었다가빠져나오는재순환하는해 수(re-circulating seawater)를포함한다(Burnett et al., 2003;
2006).
공극수중용존화학성분들의농도는퇴적물내에서이동하 는동안산화-환원환경(redox condition)에따른용출과흡착, 파도나조석등에의한상부해수와활발한교환, 다른이화학 적특성을가진지하수의유입등다양한요인에의해서시· 공간적으로큰변화를보인다(Charette et al., 2005; Charette
제주도 조간대 공극수중 영양염류 시공간적 변화 705
and Sholkovitz, 2006; Hwang et al., 2008). 따라서, 이러한공 극수의흐름은퇴적물내에서용존화학성분의분포와퇴적물 내서식하는저서미세조류나저서동물의분포에매우중요하 다(Hwang et al., 2008; Waska and Kim, 2010; 2011). 퇴적물 내에서공극수의유동은퇴적물의조성과밀접한관련이있으 며, 투수성이뛰어난모래로이루어진사질지역에서더욱활 발하다. 특히, 확산(diffusion)이점토와실트퇴적물에서해양 으로물질을공급하는중요한과정이라고한다면, 사질퇴적물 에서는공극수의이류적흐름, 즉해저지하수의유출이해양으 로물질을공급하는중요한과정이라할수있다(Huettel et al., 1998).
최근, 해저지하수유출량이강물과비슷하거나높다는사실 이밝혀지면서전세계의많은 연구자들에게관심을받고있 다(Taniguchi et al, 2002; Burnett et al., 2003; Burnett et al., 2006; Kim et al., 2005; Moore et al., 2008). 특히, 일부연구결 과들에의하면, 해저지하수가해양에서영양염류의물질수지
에중요한공급원인것으로밝혀지고있다. 미국동부의 Mas-
sachusetts 부근의염습지(salt marsh)에서염습지내영양염 류의공급에해저지하수가중요한역할을하고(Valiela et al., 1990; Krest et al., 2000), 미국 New York의 Great South Bay 에서만내해수중질산염의 50%가해저지하수를통해공급 된다고보고되었다(Capone and Slater, 1990). 또한, 한반도연 안해역에서도남해안의여자만과가막만등과같이반폐쇄적 인내만해역에서만내영양염류중질산염과규산염의약 80%
이상이해저지하수에의해공급되는것으로밝혀지기도하였 다(Hwang et al., 2005a, 2010a; Lee et al., 2009).
이러한해저지하수를통한영양염류의유입은연안부영양화 를야기하고(Valiela et al., 1990), 조간대저서미세조류 (Was- ka and Kim, 2010; 2011), 식물플랑크톤의기초생산(LaRoche et al, 1997; Herrera-Silveira, 1998) 및적조발생(Lee and Kim, 2007; Lee et al., 2010) 등과같은연안생태계에큰영향 을줄수있다. 따라서, 연안해역으로유입되는해저지하수와 지하수기원영양염류유입량을파악하는것이무엇보다중요 하다. 해저지하수를통한영양염류유입량은해저지하수의유 출속도와공극수나지하수중영양염류농도에의해크게달라 진다. 지금까지해저지하수의유출속도에대해서는전세계적 으로수동혹은자동 seepage mater를이용하거나(Cable et al., 1997; Kim et al., 2003; Taniguchi et al., 2006; Burnett et al., 2007), 지하수중에높은농도로존재하는 Ra 동위원소, 222Rn, CH4등과같은지화학적추적자(Moore, 1996; Charette et al., 2001; Kelly and Moran, 2002; Hwang et al., 2005b), 물수지 (water or salt balance) 및수리·지질학적 모델(hydrogeologic assumption, Darcy’s Law) 등과같은모델링기법(Oberdorfer et al., 1990; Oberdorfer, 2003) 등유출속도를알아내는다양 한방법을이용하여해저지하수의유출량및시간적변화에대 한많은연구가진행되어져왔으며, 일정시기의해저지하수를
통한영양염류유입량에대해서도일부연구가진행되었다. 하 지만, 해저지하수를통한영양염류유입량산정에중요한공극 수중영양염류농도의시·공간적변화에대해서는그중요성 에도불구하고아직충분한연구가이루어지지않고있다.
따라서, 이연구에서는해저지하수를통한영양염류유입량 산정에중요한공극수중영양염류의시·공간적변화특성을파 악하고자한반도연안에서해저지하수유출이가장활발하다 고알려져있는화산섬인제주도를연구지역으로선정하여연 안사질조간대지역에서퇴적물과공극수중여러가지지화학 적인자들에대하여조사하였다.
재료 및 방법
연구지역제주도는총면적이약 1,830 km2, 해안선의길이가 263 km 달하는한반도남해에서가장큰화산섬(volcanic island)이다 (Booh et al., 2005). 장축인동서방향이약 74 km, 단축인남
북방향이약 32 km 인동북동-서남서방향성을가진반타원
체의형태를갖추고있다(Kim et al., 2011a; Youn and Kim, 2011). 섬의중앙부에는높이가약 1,950 m인순상화산(shield volcano)인한라산이위치하고있으며, 그주변에는약 360여 개의다양한크기의오름이분포한다. 이산을중심으로동서
방향의지형은기울기가약 3-5° 로경사가매우완만한반면,
남북방향으로는기울기가약 5-8° 로경사가비교적급한편이 다(Kang et al., 2008).
제주도는지역적인특성상해양성기후의영향을받는동시 에동북아시아의몬순기후의영향을받아연평균강수량이약
1,900 mm 이상으로한반도내륙지방에비해강우량이약 600
mm가더많은다우지역으로알려져있다(Oh et al., 2006). 계 절적으로강우량의차이는크며, 장마와태풍의영향을빈번 히받아하계집중형의강수형태를보인다. 또한, 섬의중앙부 에위치한한라산의지형적인효과로인해국지적인집중호우 가자주발생하여지역적으로도강우량의차이가커해안지역 에서고도가높은산간지역으로갈수록강우량이많다(Park et
al., 2011). 대륙주변의연안지역과달리하천이나강과같은배
수시설이잘발달되어있지않고, 대부분의하천은투수층과 주상절리를통하여유수가쉽게지하로침투되어건천을이루 고있으며강우시에일시적으로유출하는간헐천의특성을가 지고있다(Youn and Koh, 1994). 또한, 지하수함량은총강우 량의약 46%로다른대륙주변부보다상당히높다(Park et al., 1994).
제주도의지질은아래에서부터중생대백악기말부터신생대 제3기초의기반암과이를부정합으로피복한시대미상의미고 결퇴적층, 서귀포층, 그리고그위로신생대제3기말플라이 오세중기부터제4기플라이스토세후기에지속된화산활동과 연관된화성쇄설성퇴적층과화산분출암류가연속적으로나
황동운·김형철·박지혜·이원찬 706
타난다(Koh et al., 2007; Kang et al., 2008). 또한, 지층의내부 에는용암동굴, 용암터널의붕괴에의해생성된공동(숨골), 파 쇄대, 냉각에의한절리대등과같은다양한투수성의지질구 조를이루고있다(Hamm et al., 2005; Won et al., 2006; Kim et al., 2011a).
조사항목 및 분석방법
제주도연안사질조간대공극수중영양염류의시·공간적변 화특성을알아보기위하여 2009년 5월부터 2010년 12월사 이에 2-3개월간격으로해저지하수유출이활발하다고알려진
대조기(spring tide)에제주도의한라산을중심으로서쪽연안
의 5개지역(이호, 곽지, 협재, 하모, 화순)과동쪽연안의 6개 지역(표선, 신양, 세화, 김녕, 함덕, 삼양)의해안가에서총 11개 의퇴적물및공극수시료를채취하였다(Fig. 1). 먼저, 퇴적물 시료는최고조이후 2시간부터 4시간사이에조간대표층 0-2 cm 내의퇴적물만을고밀도폴리에틸렌병(high density poly- ethylene bottle)에담아냉장및냉동상태로보관하여실험실 로운반한후입도(grain size)와강열감량(ignition loss, IL), 화 학적산소요구량(chemical oxygen demand, COD), 산휘발성 황화물(acid volatile sulfide, AVS)을 Hwang et al. (2011)이실 시한방법에따라분석하였다.
공극수시료는퇴적물채취와동시에퇴적물채취정점주변
에Rhizon sampler를설치하여공극수를직접채수하거나깊
이약 5 cm의작은구멍을만들어고이는공극수를주사기로
채취하였다. 공극수중수온과염분은휴대용염분계(Oakion, Model Salt 6 and Hach, Model Sension 5)를이용하여현장 에서직접측정하였으며, 영양염류(NO3--N, NO2--N, NH4+-N,
PO43-P, [Si(OH)4]는 25 mm GF/F 여과지와주사기형여과세 트를이용하여현장에서바로여과한후 15 mL conical tube에 담아냉동상태로실험실로옮겨영양염자동분석기(Alliance, Model INTEGRAL FUTURA and Seal analytical GmbH,
Model QUAATRO)로분석하였다이때, 질소계영양염류인
질산질소(NO3--N), 아질산질소(NO2--N), 암모니아질소(NH4+- N)의합을용존무기질소(dissolved inorganic nitrogen, DIN), 인산인 (PO43--P)과규산규소[Si(OH)4]는각각 용존무기인 (dissolved inorganic phosphorus, DIP)와용존무기규소(dis- solved inorganic silicate, DSi )로정의하였다.
결과 및 고찰
퇴적물의 입도 및 유기물 함량제주도연안사질 조간대의퇴적환경특성을살펴보기위 하여 2009년 7월부터 2010년 5월까지총 5회에걸쳐조사한 각정점별퇴적물중평균입도(mean grain size, Mz), 함수율 (water content, WC), IL, COD, AVS 분석결과를 Table 1에나 타내었다. 제주도는몬순계절풍의영향을받아 여름철에비 해겨울철에부유사의양이더많아여름에는퇴적되고겨울 에는침식되는전형적인개방형의해안특성을보이는곳이다 (Youn and Koh, 1994). 퇴적물의입도분석결과를바탕으로 각시기별조사정점에따른자갈, 모래, 펄함량을 Folk(1968) 의삼각좌표에도시한결과, 퇴적물은주로사(sand), 약역질사 (slightly gravelly sand, (g)S), 역질사(gravelly sand, gS)의총 3개퇴적물유형(sedimentary type)이나타났다(Fig. 2). 공간 Table 1. The concentrations of geochemical parameters in the intertidal surface sediments of Jeju Island from July 2009 to May 2010.
The parenthesis represents the average and standard deviation of each parameter.
Station Mz WC IL COD AVS
No. (Ø) (%) (%) (mgO2/g·dry) (mgS/g·dry)
Western coast St. 1 1.4-2.0 (1.7±0.2) 26-43 (33±6) 1.7-4.2 (2.8±1.0) 0.9-2.3 (1.5±0.6) ND1 St. 2 0.7-1.4 (1.0±0.3) 25-39 (33±5) 2.5-3.8 (3.2±0.4) 0.8-2.6 (1.4±0.7) ND St. 3 1.3-1.9 (1.6±0.2) 36-42 (40±2) 3.1-5.5 (4.2±0.9) 1.1-2.8 (1.9±0.6) ND St. 4 1.8-2.2 (2.0±0.1) 15-35 (25±7) 2.4-3.4 (2.7±0.4) 0.5-3.4 (1.3±1.2) ND St. 5 1.5-2.3 (1.8±0.3) 17-27 (23±3) 3.5-7.3 (4.8±1.4) 0.5-1.6 (0.9±0.4) ND
Eastern coast St. 6 1.7-2.1 (2.0±0.1) 31-52 (45±9) 3.6-5.4 (4.8±0.7) 1.6-4.2 (3.3±1.0) ND St. 7 1.5-1.9 (1.7±0.1) 24-32 (29±3) 3.9-5.9 (4.7±0.7) 0.7-2.1 (1.5±0.5) ND St. 8 1.7-2.0 (1.8±0.1) 28-47 (38±8) 2.8-6.8 (4.4±1.6) 2.5-4.3 (3.5±0.7) ND St. 9 1.3-1.9 (1.7±0.2) 40-61 (46±8) 2.8-6.8 (4.5±1.4) 2.0-5.3 (3.0±1.3) ND St. 10 0.9-1.3 (1.1±0.2) 49-57 (53±3) 3.3-6.6 (5.0±1.2) 2.7-5.7 (3.8±1.1) ND St. 11 1.7-2.2 (1.9±0.2) 25-31 (28±2) 1.3-2.0 (1.7±0.3) 0.3-1.3 (0.8±0.4) ND
1ND = Not Detected
제주도 조간대 공극수중 영양염류 시공간적 변화 707
Fig. 4. The average concentrations of ignition loss (IL) and chem- ical oxygen demand (COD) in intertidal surface sediment with each sampling period in the western and eastern coasts of Jeju Island from July 2009 to May 2010.
적으로제주도북서쪽의정점 2와정점 3, 제주도동쪽의정점 7, 정점 8, 정점 10 은연구기간내내약역질사((g)S), 제주도북 쪽의정점 11은사(S)로이루어져있었으며, 그외정점들은약 역질사((g)S)가우세한가운데사(S) 혹은역질사(gS)가시기 별로반복되었다. 이같은결과는퇴적물의시간에따른평균 입도변화에서도잘반영되어나타난다.
Folk and Ward (1957) 계산식에의하여구한퇴적물의통계
학적특성을나타내는 Mz는연구기간내모든정점에서 0.5-
2.5 Ø 범위로극조립사(very coarse sand)와세립사(fine sand) 사이였으며각정점별로 Mz의시간에따른변화는거의없었 다. 이는 Youn and Koh (1994)가제주도연안해빈퇴적물을
계절별로조사한결과, 입도가주로 0-3 Ø 범위에분포하였다
는이전의연구결과와아주잘일치한다. 공간적으로도제주도 북서쪽의정점 2과북동쪽의정점 10에서각각평균 1.0 Ø 과
1.1 Ø로다른제주도연안지역에비해상대적으로낮은 Mz값
을보이지만(Fig. 3), 서로뚜렷한 Mz의차이는아니었다. 이와 같은결과는제주도가다른대륙연안지역과달리보다세립한 퇴적물을공급할수있는하천이발달되어있지않고제주도 연안전체가개방형의환경특성을가지고있어보다세립한 퇴적물은외해로빠져나감으로써서로비슷한퇴적상을가지 고있기때문인것으로생각된다. 일반적으로연구지역과같이 중립사혹은세립사퇴적물로이루어져있고외해와노출되어 있는개방형의해안에서는조석이나파랑과같은작은수리역 학적에너지에도퇴적물이쉽게재부유되어다른지역으로이 동하는특성을보인다(Ryu et al., 2006; Jung et al., 2010).
퇴적물중 WC 는연구기간내 15-65% 범위였으며, 각정
점별시간에따른변화는크지않았다. 그러나, 정점별비슷한 Mz를보임에도불구하고공간적으로는큰차이를보였는데 제주도남서쪽의정점 4와정점 5, 제주도북쪽의정점 11이다
126°20'E 126°30' 126°45' 127°00'
33°15'33°30'
0
St.9 N
KOREAS
Jeju Island
W E
Gimyeong Hagwi
Gwakji Hyeopjae Gosan
Hamo Hwasun Seogwipo Namwon
Pyoseon Sinyang Seongsan
Sehwa Jeju SamyangHamdoek
St.10 St.11 St.1
St.2 St.3
St.4 St.5
St.6 St.7 St.8
10 20km
G=Gravel sG=sandy gravel msG=muddy gravel mG=muddy gravel gM=gravel mud gmS=gravel muddy sand (g)M=slightly gravelly mud (g)mS=slight gravelly mud (g)S=slightly gravelly sand M=mud
sM=muddy mud mS=muddy sand S=sand
GRAVEL
MUDM1:9 (g)MsM Mud:Sand5:5 (g)mSmS 9:1(g)SSSAND
gM gmS gS
mG G 80%
Percent Gravel 30%
trace5%
0.01%
msG sG
10
Mean Grain Size (Ø)WC (%)IL (%) IL (%)
COD (mgO2/g∙dry)DSi (µM)DIP (µM)DIN (µM)Salinity (psu) DSi (µM)DIN/DIP ratio
DIP (µM) DIN and DSi (µM) DIP (µM)
DIN (µM)Salinity (psu) COD (mgO2/g∙dry))
8 6
2009July Sep.
Sampling Date Sampling Date
Sampling Date
Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
4 2 0
10 8 6 4 2 100
8 6 4 2 0 100 80 60 40 20 0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
Western Coast 10
8 6 4 2 100
8 6 4
35 30 25 20 15 10 5 0
2 0
Eastern Coast
500 400 300 200 100 0
500 400 300 200 100
40 30 20 10 0
0 20 15 10 5
0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
500 400 300 200 100 500 0
400 300 200 100 0
Western Coast Eastern Coast
20 15 10 5
400
300
200
100
0
20
15 DINDSi DIP
10
<10 10-15 15-20 20-25
Salinity (psu)
25-30 30<
5
0 0
400 300 200 100 0
Fig. 1. A map showing the location of study area and the sampling sites for collecting the sediment and pore water in intertidal sandflat of Jeju Island from May 2009 to December 2010. The dotted line represents the boundary between the western and eastern coasts in Jeju Island in order to determine the characteristics of geochemical parameters in sediment and pore water .
126°20'E 126°30' 126°45' 127°00'
33°15'33°30'
0
St.9 N
KOREAS
Jeju Island
W E
Gimyeong Hagwi
Gwakji Hyeopjae Gosan
Hamo Hwasun Seogwipo Namwon
Pyoseon Sinyang Seongsan
Sehwa Jeju SamyangHamdoek
St.10 St.11 St.1
St.2 St.3
St.4 St.5
St.6 St.7 St.8
10 20km
G=Gravel sG=sandy gravel msG=muddy gravel mG=muddy gravel gM=gravel mud gmS=gravel muddy sand (g)M=slightly gravelly mud (g)mS=slight gravelly mud (g)S=slightly gravelly sand M=mud
sM=muddy mud mS=muddy sand S=sand
GRAVEL
MUDM1:9 (g)MsM Mud:Sand5:5 (g)mSmS 9:1(g)SSSAND
gM gmS gS
mG G 80%
Percent Gravel 30%
trace5%
0.01%
msG sG
10
Mean Grain Size (Ø)WC (%)IL (%) IL (%)
COD (mgO2/g∙dry)DSi (µM)DIP (µM)DIN (µM)Salinity (psu) DSi (µM)DIN/DIP ratio
DIP (µM) DIN and DSi (µM) DIP (µM)
DIN (µM)Salinity (psu) COD (mgO2/g∙dry))
8 6
2009July Sep.
Sampling Date Sampling Date
Sampling Date
Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
4 2 0
10 8 6 4 2 100
8 6 4 2 0 100 80 60 40 20 0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
Western Coast 10
8 6 4 2 100
8 6 4
35 30 25 20 15 10 5 0
2 0
Eastern Coast
500 400 300 200 100 0
500 400 300 200 100
40 30 20 10 0
0 20 15 10 5
0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
500 400 300 200 100 500 0
400 300 200 100 0
Western Coast Eastern Coast
20 15 10 5
400
300
200
100
0
20
15 DINDSi DIP
10
<10 10-15 15-20 20-25
Salinity (psu)
25-30 30<
5
0 0
400 300 200 100 0
Fig. 2. The ternary diagram showing the major sediment types of surface sediment in the intertidal zone of Jeju Island from July 2009 to May 2010.
126°20'E 126°30' 126°45' 127°00'
33°15'33°30'
0
St.9 N
KOREAS
Jeju Island
W E
Gimyeong Hagwi
Gwakji Hyeopjae Gosan
Hamo Hwasun Seogwipo Namwon
Pyoseon Sinyang Seongsan
Sehwa Jeju SamyangHamdoek
St.10 St.11 St.1
St.2 St.3
St.4 St.5
St.6 St.7 St.8
10 20km
G=Gravel sG=sandy gravel msG=muddy gravel mG=muddy gravel gM=gravel mud gmS=gravel muddy sand (g)M=slightly gravelly mud (g)mS=slight gravelly mud (g)S=slightly gravelly sand M=mud
sM=muddy mud mS=muddy sand S=sand
GRAVEL
MUDM1:9 (g)MsM Mud:Sand5:5 (g)mSmS 9:1(g)SSSAND
gM gmS gS
mG G 80%
Percent Gravel 30%
trace5%
0.01%
msG sG
10
Mean Grain Size (Ø)WC (%)IL (%) IL (%)
COD (mgO2/g∙dry)DSi (µM)DIP (µM)DIN (µM)Salinity (psu) DSi (µM)DIN/DIP ratio
DIP (µM) DIN and DSi (µM) DIP (µM)
DIN (µM)Salinity (psu) COD (mgO2/g∙dry))
8 6
2009July Sep.
Sampling Date Sampling Date
Sampling Date
Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
4 2 0
10 8 6 4 2 100
8 6 4 2 0 100 80 60 40 20 0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
Western Coast 10
8 6 4 2 100
8 6 4
35 30 25 20 15 10 5 0
2 0
Eastern Coast
500 400 300 200 100 0
500 400 300 200 100
40 30 20 10 0
0 20 15 10 5
0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
500 400 300 200 100 500 0
400 300 200 100 0
Western Coast Eastern Coast
20 15 10 5
400
300
200
100
0
20
15 DINDSi DIP
10
<10 10-15 15-20 20-25
Salinity (psu)
25-30 30<
5
0 0
400 300 200 100 0
황동운·김형철·박지혜·이원찬 708
른정점들에비해상대적으로낮은 WC를보였다(Fig. 3). 이는 각정점별퇴적물채취위치즉, 조위가서로다르고, 조석주기 에따른시료채취시간의차이때문인것으로보인다. 유기물 함량특성을나타내는 IL과 COD는연구기간동안각각 1.3- 7.3% 와 0.5-5.7 mg O2/g·dry 범위로각정점별시간에따른 변동은적었으나, 공간적으로는큰차이를보였다. 낮은 WC 를보였던제주도남서쪽의정점 4 와정점 5, 그리고제주도북
쪽의정점 11에서다른정점들에비해낮은 IL과 COD 값을나 타내었다 (Fig. 3). 또한, 제주도의한라산을중심으로서쪽에
분포하는정점 1-5과동쪽에분포하는정점 6-11 지역의퇴적
물중 IL과 COD 농도의평균값을비교한결과, 2010년 5월을 제외하면대체로퇴적물중 IL과 COD는제주도동쪽지역이 서쪽지역에비해다소높은농도를보였다(Fig. 4). 이는제주 도동쪽지역의퇴적물중에생물기원유기쇄설성퇴적물 (bio-
126°20'E 126°30' 126°45' 127°00'
33°15'33°30'
0
St.9 N
KOREAS
Jeju Island
W E
Gimyeong Hagwi
Gwakji Hyeopjae Gosan
Hamo Hwasun Seogwipo Namwon
Pyoseon Sinyang Seongsan
Sehwa Jeju SamyangHamdoek
St.10 St.11 St.1
St.2 St.3
St.4 St.5
St.6 St.7 St.8
10 20km
G=Gravel sG=sandy gravel msG=muddy gravel mG=muddy gravel gM=gravel mud gmS=gravel muddy sand (g)M=slightly gravelly mud (g)mS=slight gravelly mud (g)S=slightly gravelly sand M=mud
sM=muddy mud mS=muddy sand S=sand
GRAVEL
MUDM1:9 (g)MsM Mud:Sand5:5 (g)mSmS 9:1(g)SSSAND
gM gmS gS
mG G 80%
Percent Gravel 30%
trace5%
0.01%
msG sG
10
Mean Grain Size (Ø)WC (%)IL (%) IL (%)
COD (mgO2/g∙dry)DSi (µM)DIP (µM)DIN (µM)Salinity (psu) DSi (µM)DIN/DIP ratio
DIP (µM) DIN and DSi (µM) DIP (µM)
DIN (µM)Salinity (psu) COD (mgO2/g∙dry))
8 6
2009July Sep.
Sampling Date Sampling Date
Sampling Date
Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
2009July Sep. Dec. Feb.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
July
2009May Sep. Sep.
Sampling Date
Dec. Feb. Dec.
2010 May.
4 2 0
10 8 6 4 2 100
8 6 4 2 0 100 80 60 40 20 0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
Western Coast 10
8 6 4 2 100
8 6 4
35 30 25 20 15 10 5 0
2 0
Eastern Coast
500 400 300 200 100 0
500 400 300 200 100
40 30 20 10 0
0 20 15 10 5
0
St. 1 St. 2 St. 3 St. 4 St. 5
St. 6 St. 7 St. 8 St. 9 St. 10 St. 11
500 400 300 200 100 500 0
400 300 200 100 0
Western Coast Eastern Coast
20 15 10 5
400
300
200
100
0
20
15 DINDSi DIP
10
<10 10-15 15-20 20-25
Salinity (psu)
25-30 30<
5
0 0
400 300 200 100 0
Fig. 3. The temporal variations of mean grain size (Mz), water content (WC), ignition loss (IL) and chemical oxygen demand (COD) in intertidal surface sediment in the western (left) and eastern (right) coasts of Jeju Island from July 2009 to May 2010.
