• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.630-638
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• 2021

In this study, we investigated the effects of dissolved inorganic and organic nutrient on the growth of dinoflagellate Alexandrium affine (LIMS-PS-2345). The maximum uptake rates (ρ_max) and half saturation constants (Ks) calculated from the uptake kinetics experiment were 77.0 pmol/cell/hr, 17.6 μM for nitrate and 15.5 pmol/cell/hr, 3.88 μM for phosphate, respectively. These results suggested that this species has high inorganic nutrient demand and a low affinity for inorganic nutrients. During the utilization of organic nutrients for A. affine, growth rates of experimental groups added by organic nitrogen (urea and glycine) and phosphorus (adenosine triphosphate and glycerol phosphate) were above 70 %, compared to the experimental groups added by inorganic nutrients. Thus, A. affine may need to utilize organic nutrients to understand the dominant strategy and advantageous position in the interspecific competition within low inorganic nutrient environments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.1
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• pp.1-17
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• 2017

This study was conducted to investigate the nutrient distribution and controlling factors in small stream estuaries. The seasonal variations of nutrient concentration (nitrate, ammonium and phosphate) were observed from 2010 to 2012 in the three streams located in Dang-hang (closed estuary: Go-seong, open estuary: Gu-man and Ma-am). The nutrient concentrations in Go-seong were significantly higher than other estuaries, because Go-seong is relatively large and has large nutrient load from the watershed. The dyke located at the estuary, also, caused the high nutrient concentration by reducing the dilution and increasing residence time. In all three streams, nitrate concentration was high at upstream and decreased toward the downstream, because high load of nutrient input were located at upstream. Dilution and biogeochemical removal toward the downstream also caused the trends. Especially, denitrification, a typical nitrogen removing process showed clear tendency of gradual decreasing from upstream to downstream. However, Ammonium and phosphate concentrations were high at upstream and decreased toward the downstream only when the nutrient loads from the rivers were high. Nutrient concentrations were low in summer and high in winter. Freshwater discharge in summer caused a decrease of the residence time and increase of the transport of nutrients to downstream and reduced the nutrient concentrations in the estuary. Nutrient removal by the biological production during high temperature periods also affected the low nutrient concentrations. Small stream estuaries showed distinct nutrient dynamics. It is necessary to understand these characteristics in order to properly manage the small stream estuary.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.71-79
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• 1999

As part of an on-going project investigating flux of materials in the Keum River Estuary, we have monitored seasonal variations of nutrients, suspended particulate matter (SPM), chlorophyll, and salinity since 1997. Meteorological data and freshwater discharge from the Keum River Dike were also used, Our goal was to answers for (1) what is the main factor for the seasonal fluctuation of nutrients in the Keum River Estuary? and (2) are there any differences in nutrient distributions before and after the Keum River Dike construction? Nitrate concentrations in the Keum River water were kept constant through the year. Whereas other nutrients varied with evident seasonality: high phosphate and ammonium concentrations during the dry season and enhanced silicate contents during the rainy season. SPM was found similar trend with silicate. During the rainy season, the freshwater discharged from the Keum River Dike seemed to dilute the phosphate and ammonium, but to elevate SPM concentration in the Keum Estuary. In addition, the corresponding variations of SPM contents in the estuarine water affected the seasonal fluctuations of nutrients in the Estuary. The most important source of the nutrients in the estuarine water is the fluvial water. Therefore, the distribution patterns of nutrients in the Estuary are conservative against salinity. Nitrate, nitrite and silicate are conservative through the year. The distribution of phosphate and ammonium on the other hand, display two distinct seasonal patterns: conservative behavior during the dry season and some additive processes during the rainy days. Mass destruction of freshwater phytoplankton in the riverine water is believed to be a major additive source of phosphate in the upper Estuary. Desorption processes of phosphate and ammonium from SPM and organic matter probably contribute extra source of addition. Benthic flux of phosphate and ammonium from the sediment into overlying estuarine water can not be excluded as another source. After the Keum River Dike construction, the concentrations of SPM decreased markedly and their role in controlling of nutrient concentrations in the Estuary has probably diminished. We found low salinity (5~15 psu) within 1 km away from the Dike during the dry season. Therefore we conclude that the only limited area of inner estuary function as a real estuary and the rest part rather be like a bay during the dry season. However, during the rainy season, the entire estuary as the mixing place of freshwater and seawater. Compared to the environmental conditions of the Estuary before the Dike construction, tidal current velocity and turbidity are decreased, but nutrient concentrations and chance of massive algal bloom such as red tide outbreak markedly increased.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.412-421
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• 2008

Nutrient limitation was examined for the Dongbak Lake based on bioassay experiments and analyses of long-term monitoring data. From the results of data analyses, molar ratios of TN/TP and DIN/DIP were higher than 16 : 1 suggesting that phytoplankton growth was potentially limited by phosphorus. Phytoplankton responded to the addition of phosphates in the incubation experiments for all seasons whereas phytoplankton did not respond to other nutrients such as ammonia, nitrate and silicates. Size fraction (net and nano size) of phytoplankton also responded to the addition of phosphorus indicating that phytoplankton growth was limited by phosphorus in the Dongbok Lake. There was also a taxonomic shift from euglenophyceae to bacillariophyceae after addition of phosphate during warm season especially.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3345-3350
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• 2014

We investigated to assess the relationships between the major nutrients and phytoplankton dynamics during the spring season in 2010 and 2011 at 23 stations in Jinhae Bay, Korea. The bay is divided into four different zones based on pollutant sources and geographical characteristics. Nutrient limitation (>80%) was significant in Zone II, which is located in central bay and is influenced by the water well mixed from outer bay. The limited nutrient was followed in Zone III and IV that was occupying between 17% and 83%. However, the low levels are being kept below 35% in Zone I, which is characterized by the semi-enclosed eutrophic area of Masan and Haegam bays. Based on the PCA (principle component analysis) analysis, the nitrogen (N) sources in 2010 were particularly dominant and it may be due to the water mixing and wastewater formed from bottom layers and sewage. In 2011, major nutrients including nitrogen, silicon and phosphorus were dominant in the bay and are supplied by the river discharge after rainfalls with low salinity conditions. In particular, the N nutrients being supplied in 2010 are correlated with pennate diatoms Pseudo-nitzchia spp. and is not related to the phytoplankton population densities in 2011. The present study suggests that N sources play an important role in the proliferation of diatom, and the rapid nutrient uptakes by them are potential nutrient limitation factors in the bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.224-232
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• 2000

Inorganic nutrient concentrations in relation to springtime physical parameters of the Yellow Sea were investigated during April 1996. Three major water masses, i.e., the Yellow Sea Warm Current Water (YSWC), Coastal Current Water (CCW) and Changjiang River Diluted Water (CRDW), prevailed in the study area. Water masses were vertically wel1 mixed throughout the study area, and nutrients were supplied adequately from bottom to surface layer. As result of ample nutrients supplied by vertical mixing together with progressed daylight condition, springtime phytoplankton blooms were observed, which was responsible for the depletion of inorganic nutrients in surface water column. Low nutrients concentration in bottom water of the central Yellow Sea (Stn. D9; nitrate: <2 ${\mu}$M, phosphate: <0.3 ${\mu}$) was associated with the entrance of YSWC which is characterized by high temperature and salinity. Influenced by runoff and vertical tidal mixing, CCW with high nutrient concentrations probably associated with China and Korea coastal waters with high nutrients concentration. For the local scale of inorganic nutrient distribution, nutrient transfers from coast to central areas were limited due to restriction imposed by tidal fronts (Stn. D6) and thus affected the horizontal nutrient profiles. Relatively high phytoplankton biomass was observed in the tidal front (Chl-${\alpha}$=12.38 ${\mu}$gL$^{-1}$) during the study period. Overall, the springtime nutrient distribution patterns in the Yellow Sea appeared to be affected by: (1) Large-scale influx of YSWC with low nutrient concentrations and CCW with high nutrient concentrations influenced by Korea and China coastal waters; (2) vertical mixing of water mass and phytoplankton distribution; and (3) local-scale tidal front as well as phytoplankton blooms alongthe tidal front.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.292-293
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• 2007

한국 남해안에서 2005년 10월부터 2006년 8월까지 격월별로 관측된 CTD 자료 및 분석된 영양염 자료를 가지고 격월별 해황 및 영양염의 분포를 살펴 보았다. 겨울철에는 표층과 저층간의 수직 혼합으로 일정한 수괴 분포 및 수온과 염분에 대해서 일정한 영양염 분포를 나타내었다. 그리고 연안역과 외양역 사이에 수온 전선이 뚜렷하였다. 그러나 여름철에는 양자강 저염수의 유입으로 T-S상에서 수형의 분포 범위가 넓었으며, 또한 수온과 염분에 대한 영양염의 분포도 일정하지 않았다. 그리고 여름철에는 저염수 유입에 의해서 수온 전선보다는 염분 전선이 뚜렷하였다. 봄과 가을에는 계절적 천이기로 수온과 염분의 분포에서 뚜렷한 pattern을 보이지 않았다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.627-639
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• 2014

In respect of the nutrients cycling in coastal environment, regeneration in bottom layer is one of major source of nutrients. We analyzed the bottom water quality at the 14 stations during 9 years from 2004 to 2012 to investigate the characteristics of nutrients at bottom layer in Jinhae Bay. Concentrations of DIN, DIP and DSi showed the large seasonal variation and were higher in summer. Especially, average concentrations of these nutrients were two times higher in hypoxic season than in normoxic season. In summer, high concentrations of DIN, DIP and DSi caused by regeneration were common feature, but spatial distribution of DSi differ from that of DIN and DIP. DIN and DIP were higher in Masan Bay, while DSi was higher in Masan Bay as well as in center of Jinhae Bay. In comparison with DIN and DIP, DSi was significantly affected by nutrients regeneration at bottom layer in whole season. According to time series analysis, DIN concentration was decreased from approximately $14{\mu}M$ to $6{\mu}M$. This result induce that Si:N ratio at bottom layer in Jinhae Bay changed from approximately 1 to 3.

• 한국해양학회지
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• v.4 no.2
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• pp.83-86
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• 1969

해양관측의 세계적인 공통성으로 해서 염분검정법이 이미 오래 전부터 통일화 되었지만 근래에 와서는 용존산소량 정량법도 국제적인 Intercalibration을 하는 등규격화에의 기운이 나고 있다. 다시 Kuroshio 합동조사에서는 영양염의 정량에 있어 공통된 표준용액을 사용하므로써 조작상의 편리와 측정치의 신뢰성을 더욱 향상시키자는 의도에서 일본이 국제적인 영양염 표준용액의 조제 및 배포에 관한 안을 내어 1965년 Manila 회의를 거쳐 일본 상모중앙화학연구소의 관원씨가 이를 맡아 1966년부터 시작하여 1967년까지에 요오드산칼리움, 아질산염, 인산염, 규산염의 표준용액을 만들어 1968년 봄부터 시험적으로 일본국내와 동남아 수개국에 나누어 사용해 왔던 것이다. 다시 1968년 9월의 SCOR 의 영양염에 관한 Working Group 회의에서 CSK Std. Solution을 사용하여 세계각국에서 현재 사용하고 있는 영양염 분석방법의 Intercalibration을 하자는 회의가 있었고, 이것을 권고사항으로 SCOR에 보고하여 1968년 11월에 ICES가 승인하므로써 Intercalibration에 관한 원칙이 정해졌다. 동시에 Finland의 Koroleff씨와 Palmork씨가 organizer로 정해졌던 것이다. 이 보다 약간 앞서 본인이 상모중연에 가 있을 때 Std. Solution으로서 아질산염용액 만으로 각종무기질소화합물의 표준용액으로 대용한다는 것은 비합리적이므로 질산염과 암모늄염의 표준용액이 있어야 한다고 주장하여 우선 질산염용액을 추가로 만들기로 하여 1968년 11월부터 표준물질의 정제부터 시작 되었다. 1969년 1월에 Intercalibration 에 관한 구체적인 회의를 위해 Scripps 해양연구소에 관원, Wooster Rakestraw, Cieskes씨등이 모여 우선 일본상모중연에서 만들고 있는 인산염, 질산염, 아질산염, 규산염의 CSK 표준용액을 표준시료로하여 SCOR 과 ICES의 해양화학분과에서 선정한 세계 100개처에 나누어 현재 각자가 사용하고 있는 방법의 정밀도와 정확도를 check하는 소위 International intercalibration을 1969년 9월부터 시작하기로 확정을 보았고, 동시에 구체적인 지시가 있었던 것이다. 이시료를 받는 사람에게는 다만 그것의 농도범위만 알려주고 정확한 농도는 Koreleff와 관원씨만이 알고 있기로 하여 측정에 분석자의 주관이 개입되지 못하도록 했고, 분석치는 SCOR가 모아 해석하되 번호제로 하여 어떤 나라의 누구가 했다는 것은 밝히지 않기로 되어 있다. 이같은 내력으로 CSK Std. Solution이 국제적인 Intercalibration용의 표준시료로서 시험적으로 사용되기 까지는 되었으나, CSK Std. Solution 그자체에 관해서는 아직도 해결해야 할 점, 개량을 요하는 점이 많다. 이하에서는 주로 개량을 요하는 점에 관해 몇가지 언급하고자 한다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.371-382
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• 1999

This paper presents the results of recent nutrients measurement and analysis in relation to other environmental parameters such as temperature, salinity, AOU and pH in the South Sea, Korea. In summer, temperature showed stronger correlation with nutrients than salinity and also did the parameters related to biological activities such as pH and AOU. Implications of above results exemplify that primary producers in the vicinity of salt front actively consumed nutrients so that nutrients-salinity correlation is strongly modified in the salt front. Nutrient in winter showed significant correlation only with temperature. Nutrient distribution seems governed by the location of thermal front between vertically mixed cold water in northern area and warm waters flowing north. Due to weak biological activity in winter pH-nutrients correlation, which was strongest in summer ($R^2$ >0.6) dropped sharply in winter ($R^2$ <0.5). Depth integrated nitrate+nitrite, phosphate and silicate values are 321 $mmol{\cdot}m^{-2}$, 23 $mmol{\cdot}m^{-2}$, 637 $mmol{\cdot}m^{-2}$ in summer and 261 $mmol{\cdot}m^{-2}$, 31 $mmol{\cdot}m^{-2}$, 742 $mmol{\cdot}m^{-2}$ in winter, respectively. NIP values in summer exhibit phosphorus deficiency, however, winter situation is reversed for nitrogen. Nitrogen input via precipitation and riverine discharge in wet season seems potentially critical for maintaining the South Sea ecosystem.