Seasonal variations of physico-chemical factors and phytoplankton communities at inner and outer ports

This study aim to understand the seasonal variations of physico-chemical factors and phytoplankton communities at inner and outer ports. We seasonally investigated environmental and biological factors in surface water at Pusan, Ulsan, Incheon and Gwangyang ports from February 2007 to August 2008. During the study periods, water temperature showed seasonal fluctuation due to air temperature at all study areas. Salinity was more than 32 psu at all study areas in winter, which showed less than 28 psu at Incheon and Gwangyang ports in summer. Also, nutrients (nitrite, nitrate, ammonia, phosphate and silicate), pH, DO, TSS, COD and chlorophyll a showed seasonal fluctuations. Water temperature was higher 0.3-1.5℃ outside than inside stations except at Incheon port in summer. Nutrients showed higher concentrations at Incheon and Gwangyang ports than Pusan and Ulsan ports, which were high concentrations at inside stations. In phytoplankton communities, a total 84 taxa were identified to the following taxonomic groups: bacillariophyceae (70), euglenophyceae (1), chrysophyceae (2) and dinophyceae (11). Diatom group which occupied one of the major components in phytoplankton communities was high in spring, autumn and winter seasons. The phytoplankton showed highest standing crops in summer (5×105 cells L-1) at Pusan port, 9×105 cells L-1 in spring at Ulsan port, 4×104 cells L-1, 13×105 cells L-1 in winter at Incheon and Gwangyang ports. Standing crops of the inside stations were higher than those of outside stations at Pusan, Ulsan and Gwangyang ports. Dominant species were Skeletonema costatum, Chaetoceors socialis and Cheatoceros pseudocrinitus at Pusan ports. At Ulsan port, dominant species were Sk. costatum and Detonula pumila. At Incheon port, dominant species were Sk. costatum and Paralia sulcata. Sk. cosataum and Odontella longicruis were dominated at Gwangyang port. As a result, physico-chemical factors showed seasonal variations and differences at inside and outs2

Distribution of dominant species and potential risky species on phytoplankton and their relationship with physico-chemical factors at major ports in Korea

This study aimed to understand a distribution of dominant species and potential risky species on phytoplankton and their relationship with physico-chemical factors at major ports in Korea in 2007. During the study periods, Chaetoceros socialis (11.1%), Ch. pseudocrinitus (10.6%) and Skeletonema costatum (10.3%) appeared to be dominant species at Pusan port. S. costatum (10.8%) and Detonula pumila (10.4%) were dominant species at Ulsan port, Paralia sulcata (20.5%) and S. costatum (30.7%) were at Incheon port, Odontella longicruis (11.3%), and S. costatum (41.8%) were at Gwangyang port. Potential risky species (red tide and toxic species) appeared 17 species in diatoms, 7 species in dinoflagellates and 1 species in Euglenoide. Multi regression of results, Ch. socialis and Ch. pseudocrinitus were affected by salinity (p<0.01) at Pusan port. At Ulsan port, dominant species (S. costatum and D. pumila) were highly affected by total suspended solids (TSS) than salinity. At Incheon port, dominant species were highly affected by chemical factors (ammonia, nitrite and phosphate) than physical factors such as water temperature and salinity. Pseudo-nitzschia spp. was affected by nutrients such as nitrite and silicate in all study areas. Alexandrium and Dinophysis were affected by COD, nitrate and phosphate at Ulsan port. As a results, indicated that dominant species were highly related to physical factors than chemical factors, while risky species were related to chemical factors such as nutrients.2

Effects of physico-chemical factors on succession of target species at ports in Korea

The red tide species (S. costatum, P. sulcata and Ch. socialis) were affected by nutrients (p0.05), because of low frequency at all seasons and areas. But toxic species appeared to be higher frequency in summer season at all ports, which were affected by temperature and nitrate (p<0.01). Jung et al. (2008) and Kang et al. (2003) reported that high occupied dominant rates in summer season at coastal waters. Also, Nishitani et al. (2005) and Lee et al. (2006) reported that the genus Alexandrium and Dinophysis were dominant species at high temperature from 15 to 25℃ and at optimum salinity from 20 to 33 psu.2

Dominant and risky species of phytoplankton and their relationship with environmental factors at major ports in Korea

This study aimed to understand relationship between dominant and risky phytoplankton species and environmental factors at major ports of Korea in 2007. During the study periods, Chaetoceros diadema (7.7 %), Ch. debilis (6.9 %), Ch. difficilis (5.1 %), Ch. pseudocrinitus (18.9 %), Ch. spp. (5.5 %) and Skeletonema costatum (10.1 %) appeared to be dominant species at Pusan port. Ch. diadema (43.8 %), Ch. pseudocrinitus (9.8 %) and S. costatum (21.2 %) were dominant species at Ulsan port, Ch. pseudocurvisetus (12.3 %), Paralia sulcata (18.1 %) and S. costatum (53.1 %) were at Incheon port, Eucampia zodiacus (17.1 %), and S. costatum (57.9 %) were at Gwangyang port. Risky species (red tide and toxic species) appeared 17 species in diatoms, 7 species in dinoflagellates and 1 species in Euglenoides. Pseudonitzschia seriata and P. pungens, which appeared at Gwangyang port during 4 seasons, are able to produce domoic acid. Alexandrium and Dinophysis were found in August throughout the study area, which can cause paralytic shellfish (PSP) and diarrhetic shellfish (DSP). Distribution pattern of Chaetoceros diadema, Ch. debilis, Ch. difficilis, Ch. pseudocrinitus and Ch. spp. was affected by salinity (p<0.01) at Pusan port. At Ulsan port, dominant species was highly affected by total suspended solids (TSS) than salinity. At Incheon port, dominant species was highly affected by chemical factors (ammonia, nitrite and phosphate) than physical factors (water temperature and salinity). Pseudo-nitzschia spp. was affected by nutrients such as nitrite and silicate in all study areas. Alexandrium and Dinophysis were affected by COD at Ulsan port. The abovementioned results indicated that dominant species were highly related to physical factors than chemical factors, while risky species were related to chemical factors.2

The change aspect of phytoplankton abundance and biomass on size fraction in mesocosm experiments

이번 연구는 메조코즘 실험내에서 크기별 식물플랑크톤 현존량과 생체량의 변화양상을 파악하는데 그 목적이 있다. 실험 기간 동안 식물플랑크톤 현존량은 대조구에서 최소 7×104 cells L-1 (T9)에서 최대 22×105 cells L-1 (T2)를 보였으며, 실험구에서는 최소 8×103 cells L-1 (T9)에서 최대 8×105 cells L-1 (T0)를 보였다. 대조구에서는 실험 시작 후 T2까지 높은 증가를 보이다 T3부터 T9까지 감소하였고, 실험구에서는 T0부터 감소하여 T7 이후로는 유사한 경향을 보였다. 클로로필 a는 대조구에서 T0 (평균 2.1 ㎍ L-1)부터 T2 (평균 2.3 ㎍ L-1)까지 유사한 농도를 보이다 T3 (평균 1.0 ㎍ L-1) 이후로 감소하였다. 실험구의 클로로필 a의 농도는 대조구와 유사한 변화양상을 보였으나, 농도는 대조구보다 높은 농도를 보였다. 사이즈 별 클로로필 농도는 대조구에서 micro 이상의 크기가 60%이상을 차지하였고 nano 크기가 30% 정도를 차지하였고, 실험구도 이와 유사하였다.식물플랑크톤 군집은 대조구에서 돌말류 47종, 와편모조류 15종, 기타조류 3종으로 총 65종이 출현하였고, 실험구는 돌말류 54종, 와편모조류 14종, 기타조류 2종으로 총 70종이 나타났다. 주요 우점종으로는 실험구에서 Chaetoceros curvisetus, Ch. compressus, Thalassiosira gravida, Skeletonema costatum이 우점종으로 나타났으며, 대조구에서는 Ch. curvisetus, Cylindrotheca closterium, Coscinodiscus wailesii, Leptocylindrus danicus등으로 나타났다.2

Environmental factors affecting dynamics of phytoplankton community in port baseline surveys in Korea

To understand the environmental factors affecting dynamics of phytoplankton communities at the busiest ports (Pusan, Ulsan, Incheon and Gwangyang) of Korea, we seasonally investigated the physico-chemical factors and phytoplankton assemblages from February 2007 to November 2008. Diatoms were the majority in the phytoplankton communities (78%). Maximum abundance of diatoms was observed at Pusan in summer 2007, and at Ulsan in spring 2007. During each period, over 60% diatoms at Pusan were Chaetoceros debilis and Ch. pseudocrinitus, and Detonula pumilia dominated at Ulsan. At the Incheon and Gwangyang ports characterized as eutrophic and semi-enclosed environments, the abundance of diatoms peaked in winter when Skeletonema costatum dominated. It corresponded to condition of lower salinity, higher concentration of chemical oxygen demand and total suspended solids compared to Pusan and Ulsan. When diatoms bloomed at the ports investigated, there were very low concentration of silicate and nitrate (p1 μM) at the four ports in summers. In contrast, low abundances of dinoflagellates occurred during the study period at Incheon. At all ports, the predominant diatoms characterized waters with low concentrations of nutrients such as silicate and nitrate, while dinoflagellates mainly occurred in summers, with increasing temperature, low salinity and high phosphate concentration.1

Effect of enhanced zooplankton on the dissolved oxygen in an enclosed ecosystem

In order to understand role of zooplankton aggregation affecting alteration in the dissolved oxygen (DO) concentration, we artificially enhanced zooplankton abundance by net towing. Thus, present study was designed to monitor the effect of N. scintillans blooms on the DO concentration by introduction of enclosed polyethylene bags (220 liter) during two weeks. DO concentration in experimental bags varied between 4.00 and 5.56 mg L-1 which is very low when compared to the ambient water(6.03 and 8.68 mg L-1) and control bags(5.20 and 7.32 mg L-1). The most dominant species, N. scintillans, representing from 52.0 to 86.0 % of total abundance in the bags, ranged from 6 to 109 individuals L-1 in ambient water, from 35 to 489 individuals L-1 in control bags and from 237 to 791 individuals L-1 in experimental bags during the study period. The high abundance of N. scintillans in experimental bags stemmed from the artificial addition of the species by net towing. Based on the above results, DO concentration showed negative relationship with N. scintillans abundance. High abundance of N. scintillans was coincident with the low concentration of DO, whereas low abundance of N. scintillans was related to the relatively high concentration of DO. The result indicates that high abundance of N. scintillans affected negatively DO concentration in the enclosed bags.2

Seasonal dynamics of ciliate plankton in four major ports in Korea

한국의 주요항만에 분포하는 섬모충플랑크톤의 계절적인 특성을 파악하고 수괴지표종인 유종섬모충을 이용하여 외래 생물종의 유입을 조사하였다. 외래 생물종의 유입은 기후변화에 따른 해류의 영향으로 인한 유입과 선박평형수(ballast water)를 통한 가능성을 두고 접근하였다. 시료의 정성 및 정량 채집은 우리나라 주요항만인 부산항, 울산항, 광양항, 인천항에서 2007년 2월부터 2008년 11월까지 이루어졌다. 조사기간 동안 출현한 유종섬모충플랑크톤은 총 15속 45종이다. 광양항에서 34종, 부산항에서 33종, 울산항에서 31종, 인천항에서 18종이 관찰되었고 무각섬모충 플랑크톤의 개체수의 범위는 566~65,151 cells L이며 유종섬모충 플랑크톤의 개체수의 범위는 10~5,973 cells L이다. 전체 섬모충 플랑크톤의 개체수의 범위는 642~65,182 cells L로 개체수의 변화는 조사 계절에 따라 큰 차이를 보였다. 미국의 오레곤 Coos Bay의 항만에서 벡터생물로 보고가 되어 있는 유종섬모충류는 Eutintinnus lusus-undae, Eutintinnus tubulosus, Favella ehrenbergii, Favella taraikaensis, Helicostomella subulata, Stenosemella nivalis, Tintinnopsis ampla, Tintinnopsis beroidea, Tintinnopsis cylindrica, Tintinnopsis directa, Tintinnopsis lohmanni, Tintinnopsis radix, Tintinnopsis rapa로 한국의 주요항만인 부산항, 울산항, 광양항, 인천항에서 총 13종이 출현하였으며 광양항에서 13종으로 가장 많은 종이 출현하였고 인천항에서 6종으로 가장 적은 종수가 관찰되었으며 부산항 10종, 울산항 11종이 관찰되었다. 유종섬모충의 출현분포의 특성은 연안종이 주로 출현하였으며 쿠로시오 해류(Kuroshio current)의 지류인 대마난류(Tsushima Warm Current)의 영향이 큰 부산과 울산항에 8월과 11월에 난류 지표종이 중점적으로 출현하고 있었던 것으로 보아 대마난류에 의해 외래종이 유입되는 것으로 판단된다.2

Seasonal dynamics of planktonic ciliates at 4 Korean major ports: Busan, Ulsan, Gwangyang and Incheon

Planktonic ciliates play an important role in food web of marine ecosystem as well as a bio-indicator for invade species from ballast waters or from changing flow of currents due to climate changes. This study was carried out in order to fine evidences for introduction of invade species. We surveyed the seasonal species composition of planktonic ciliate to find out the evidence for invade species ae Busan, Ulsan, Gwangyang and Incheon in Korean major ports fro February 2007 to November 2008. A total of 45 ciliate species, belonging to 14 genera, were identified during the study period. In each port, 34 species occurred at Gwangyang, 33 at Busan, 31 at Ulsan, 18 at Incheon, respectively. The abundance of naked ciliates ranged from 266 to 65,151 cells/L and that of tintinnids 10 to 5,973 cells/L.13 spp. Of tintinnids such as Eutintinnus lusus-undae, Eutintinnus tubulosus, Facella ehrenbergii, Favella taraikaensis, Helicostomella subulata, Stenisemella nivalis, Tintinnopsis ampla, Tintinnopsis beroidea, Tintinopsos cylindrical, Tintinnopsis direcra, Tintinnopsis lohmanni, Tintinnopsis radix, Tintinnopsis rapa are classified as a vector species based on a report from Coos Bay in Oregon, USA. This vector species occurred highest with 13 spp. at Gwangyang port. Most tintinnid species occurred as neritic species throughout the survey, while some warm water species occurred only for a short period at Busan, Ulsan and Gwangyang ports where Tsushima warm current might affect seasonally. It suggests that the influence of the warm water species might be affected by influx of Tsushima warm current.1

Microcosm과 Mesocosm에서 유류오염에 따른 플랑크톤 군집의 반응

해양생태계에서 유류오염에 따른 플랑크톤 군집의 반응을 알아보고자 10 L 규모의 microcosm과 5m 수심의 1 ton 규모의 mesocosm 실험을 수행하였다. Microcosm은 원유 농도별(10 μL L-1, 100 μL L-1, 1 mL L-1, 5 mL L-1, 10 mL L-1) 위해성 평가를 선행하였다. Microcosm 실험에서 임계 원유 농도를 설정하였고, 이를 근거로 유화제 처리에 따른 플랑크톤 군집의 반응을 mesocosm에서 조사하였다. Microcosm에서 1 mL L-1이상 원유 노출구에서 동물플랑크톤 및 식물플랑크톤 개체수가 빠르게 감소하였고, 반대로 종속영양세균 개체수는 빠르게 증가하였다. 그러나 100 μL L-1이하 원유 노출구는 대조구와 차이를 보이지 않아, 플랑크톤 군집에 영향을 미치는 원유 농도는 1 mL L-1이상으로 판단되었다. Mesocosm에서 원유 1 mL L-1 노출구 및 유화제(원유 농도의 1/10 처리)를 함께 처리한 유류 및 유화제 노출구에서 반응은 유류 및 유화제 노출시 동물플랑크톤은 수심에 상관없이 100% 치사를 보인 반면, 유류만 처리시 표층에서는 100%, 중층 및 저층에서 60-70%의 치사율을 보였다. 식물플랑크톤 개체수는 수심에 상관없이 유류 및 유화제 노출구에서 지속적으로 감소하는 반면, 유류 및 대조구는 초기 감소 후 재증가하였다. 종속영양세균는 유류 및 유화제 노출구에서 초기 2일까지 빠르게 증가후 감소를 하였으며, 유류 노출구 및 대조구는 소폭의 증가를 보였다. HNF (heterotrophic nano flagellate)는 유류 및 유류+유화제 노출시 3일부터 증가하였으며, 이는 종속영양세균을 포식함에 있다고 판단된다. 따라서 폐쇄형 인공생태계 실험을 통한 유화제 처리시 부유생태계는 가장 큰 영향을 받는 것으로 판단된다.2