Hydrographically mediated patterns of photosynthetic pigments in the East/Japan Sea: Low N:P ratios and cyanobacterial dominance

Kim, Tae-Hoon,Lee, Yong-Woo,Kim, Guebuem Elsevier 2010 Journal of marine systems Vol.82 No.1

<P><B>Abstract</B></P><P>Nutrients and photosynthetic pigments were measured over a north–south transect of the East/Japan Sea (EJS), which includes various oceanographic environments such as the cold and warm-water masses, sub-polar fronts, and eddies in the surface ocean. Sampling was conducted in May 2004, July 2005, and October 2005. The N:P ratios were low (<4) for high chlorophyll <I>a</I> areas owing to the active Redfieldian consumption of N and P from waters with a low N:P ratio (approximately 13) in the entire EJS. The compositions of photosynthetic pigments were used for identifying phytoplankton groups at a class level using the CHEMTAX program. It is notable that cyanobacteria (40–60%) dominated the phytoplankton community in the frontal zone in 2004 and formed approximately 10–50% of the community over the entire surface layer in 2005. This dominance of cyanobacteria appears to be associated with the seawater conditions of low N:P ratio and optimum temperature. As such, the relative amount of prymnesiophytes increased with a decrease in the N:P ratio in the upper 200m of the EJS. In contrast, more preferentially in high N:P ratio areas, diatoms (40–80%) dominated the phytoplankton community in May 2004 because of the spring bloom, and pelagophytes (20–60%) dominated the community in July and October 2005. Therefore, the EJS seems to provide an ideal environment for studying the physical and chemical factors that control the community structures of phytoplankton.</P>

Strong linkages between surface and deep-water dissolved organic matter in the East/Japan Sea

Kim, Tae-Hoon,Kim, Guebuem,Shen, Yuan,Benner, Ronald European Geosciences Union 2017 Biogeosciences Vol.14 No.9

<P>Vertical and horizontal distributions of total dissolved amino acids (TDAAs), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) were measured in the East/Japan Sea (EJS). The euphotic zone of this sea is N-limited, and the N:P ratio is similar to 13 below 200m depth. Elevated TDAA concentrations (137 +/- 34 nM) and DOC-normalized yields (0.8 +/- 0.2% of DOC) were observed in deep waters (>= 1000 m) of the EJS and compared with those in the deep North Pacific Ocean. Significantly high TDAA concentrations and yields were observed in a region of deep-water formation, indicating the convection of margin-derived bioavailable dissolved organic matter (DOM) to deep waters. Declining TDAA concentrations (36 +/- 12 %) and yields (33 +/- 13 %) were observed between 1000 and 3000m throughout the EJS, indicating the utilization of bioavailable DOM in deep waters. Concentrations of the D-enantiomers of amino acids (Ala, Glx, Asx, and Ser) were relatively high in deep waters of the EJS, indicating substantial bacterial contributions to DOM from surface and upper mesopelagic waters. Climate warming during the past few decades in the EJS is weakening deep convection during the winter, and one consequence of this reduction in deep convection is a decline in the supply of bioavailable DOM from surface waters.</P>

Nutrient input from submarine groundwater discharge versus intermittent river-water discharge through an artificial dam in the Yeongsan River estuary, Korea

Kim, Jihyuk,Kim, Jong-Sun,Kim, Guebuem Springer-Verlag 2010 OCEAN SCIENCE JOURNAL Vol.45 No.3

Tidal influence on the sea-to-air transfer of CH₄ in the coastal ocean

HAHM, DOSHIK,KIM, GUEBUEM,LEE, YONG-WOO,NAM, SUNGH-YUN,KIM, KYUNG-RYUL,KIM, KUH Munksgaard International Publishers 2006 Tellus. Series B, Chemical and physical meteorolog Vol.58 No.1

<P>ABSTRACT</P><P>We obtained real-time monitoring data of water temperature, salinity, wind, current, CH<SUB>4</SUB> and other oceanographic parameters in a coastal bay in the southern sea of Korea from July 8 to August 15, 2003, using an environmental monitoring buoy. In general, the transfer velocity of environmental gases across the air–sea interface is obtained exclusively from empirical relationships with wind speeds. However, our monitoring data demonstrate that the agitation of the aqueous boundary layer is controlled significantly by tidal turbulence, similar to the control exercised by wind stress in the coastal ocean. The sea-to-air transfer of CH<SUB>4</SUB> is enhanced significantly during spring tide due to an increase in the gas transfer velocity and vertical CH<SUB>4</SUB> transport from bottom water to the surface layer. Thus, our unique time-series results imply that the sea-to-air transfer of gases, such as CH<SUB>4</SUB>, DMS, DMHg, N<SUB>2</SUB>O, CO<SUB>2</SUB> and <SUP>222</SUP>Rn, from highly enriched coastal bottom waters, is controlled not only by episodic wind events but also by regular tidal turbulence in the coastal ocean.</P>

해양산업시설의 위험유해물질 배출규제에 대한 국내외 현황 연구

최기영(Ki Young Choi),김창준(Chang Joon Kim),김영일(Young Il Kim),김규범(Guebuem Kim),오상우(Sangwoo Oh),이문진(Moonjin Lee) 한국해양환경·에너지학회 2021 한국해양환경·에너지학회 학술대회논문집 Vol.2021 No.10

현행 HNS 해양배출 규제와 관련한 국내 해양환경관리법에서는 오염물질의 해양배출 금지원칙과 예외적 배출허용 기준을 규정하고 있으며, 물환경보전법에 명시된 예외적 배출허용기준 등을 위임하고 있다. 또한 환경정책기본법은 일부 해역에 적용되는 해양환경기준을 규정하고 있다. 국내 해양환경관리법의 범위가 주로 선박으로부터의 오염규제에 한정 되어 있기 때문에, 해양산업시설의 HNS 배출에 대한 허용기준 및 배출 지침 수립 등의 체계적 배출 제도 정립을 통한 해양환경관리체계 구축이 필요하다. 국외 사례의 경우 해양으로 배출되는 산업폐수 배출에 대한 허가제도와 배출 시 준수해야하는 산업종별 세부 배출가이드라인을 규정하고 있다. 이와 관련된 배출허용물질 선정 및 우선 순위설정 방법, 절차, 배출방법 등을 체계화하고 있으며, 1970년대 이후부터 위험유해물질(HNS)의 해양배출에 대한 규제 필요성을 인식하여 배출 규제체계 강화는 추세이다. For the current Korean legal system related to HNS marine discharge regulations, the Marine Environment Management Act stipulates the principle prohibiting marine discharge of pollutants and exceptional acceptance standards specified in the Water Environment Conservation Act. In addition, the Framework Act on Environmental Policy defines marine environmental standards applied to some limited sea areas. In Korea, since the Marine Environment Management Act primarily focuses on pollution control from ships, It is necessary to establish a marine environment management system for HNS emission from marine industrial facilities. In Europe, the USA, and Japan, the discharge regulation system has been strengthened since the 1970s. The permission system for the industrial wastewater discharged into the sea, and detailed guidelines for each industry are stipulated.

Speciation and Sources of Brown Carbon in Precipitation at Seoul, Korea: Insights from Excitation–Emission Matrix Spectroscopy and Carbon Isotopic Analysis

Yan, Ge,Kim, Guebuem American Chemical Society 2017 Environmental science & technology Vol.51 No.20

<P>Brown carbon (BrC) plays a significant role in the Earth's radiative balance, yet its sources and chemical composition remain poorly understood. In this work, we investigated BrC in the atmospheric environment of Seoul by characterizing dissolved organic matter in precipitation using excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). The two independent fluorescent components identified by PARAFAC were attributed to humic-like substance (HULIS) and biologically derived material based on their significant correlations with measured HULIS isolated using solid-phase extraction and total hydrolyzable tyrosine. The year-long observation shows that HULIS contributes to 66 +/- 13% of total fluorescence intensity of our samples on average. By using dual carbon (C-13 and C-14) isotopic analysis conducted on isolated HULIS, the HULIS fraction of BrC was found to be primarily derived from biomass burning and emission of terrestrial biogenic gases and particles (>70%), with minor contributions from fossil-fuel combustion. The knowledge derived from this study could contribute to the establishment of a characterizing system of BrC components identified by EEM spectroscopy. Our work demonstrates that, EEM fluorescence spectroscopy is a powerful tool in BrC study, on the basis of its chromophore resolving power, allowing investigation into individual components of BrC by other organic matter characterization techniques.</P>

Tracing the flow rate and mixing ratio of the Changjiang diluted water in the northwestern Pacific marginal seas using radium isotopes : LEE ET. AL.; TRANSPORT OF CHANGJIANG DILUTED WATER

Lee, Hojun,Kim, Guebuem,Kim, Jeonghyun,Park, Gwanserk,Song, Ki-Hoon American Geophysical Union 2014 Geophysical research letters Vol.41 No.13

Rare earth element distributions and fractionation in plankton from the northwestern Mediterranean Sea

Strady, Emilie,Kim, Intae,Radakovitch, Olivier,Kim, Guebuem Elsevier 2015 CHEMOSPHERE - Vol.119 No.-

<P><B>Abstract</B></P> <P>Rare earth element (REE) concentrations were measured for the first time in plankton from the northwestern Mediterranean Sea. The REE concentrations in phytoplankton (60–200μm) were 5–15 times higher than those in four size fractions of zooplankton: 200–500μm, 500–1000μm, 1000–2000μm and >2000μm. The concentrations within these zooplankton fractions exhibited the same ranges with some variation attributed to differences in zooplankton taxonomy. The REE concentrations in plankton were poorly related to the reported REE concentrations of seawater, but they correlated well with the calculated REE<SUP>3+</SUP>, concentrations especially with regard to middle REE (MREEs) and heavy REEs (HREEs). Plankton and seawater revealed different PAAS-normalised REE distributions, with the greatest differences observed in the light REEs. Interestingly, a comparison of PAAS-normalized sediment particles from the study of Fowler et al. (1992) showed concentrations of the same order of magnitude and a similar REE distribution without MREE enrichment. Based on this comparison, we propose a conceptual model that emphasizes the importance of biological scavenging of REEs (especially LREEs) in surface waters.</P> <P><B>Highlights</B></P> <P> <UL> <LI> REE concentrations were measured for the first time in plankton from Mediterranean Sea. </LI> <LI> REE concentrations in plankton were poorly related to the reported REE concentrations of seawater. </LI> <LI> REE concentrations in plankton correlated well with calculated free REE(III). </LI> <LI> PAAS–REE concentrations are in the same order of magnitude than PAAS-normalized sediment particles. </LI> <LI> PAAS–REE concentrations have similar distribution than PAAS-normalized sediment particles except MREE. </LI> </UL> </P>

Linking groundwater-borne nutrients and dinoflagellate red-tide outbreaks in the southern sea of Korea using a Ra tracer

Lee, Yong-Woo,Kim, Guebuem Academic Press in association with the Estuarine a 2007 Estuarine, coastal and shelf science Vol.71 No.1-2

<P><B>Abstract</B></P><P>We have measured nutrients, photosynthetic pigments, and two radium isotopes (<SUP>223</SUP>Ra and <SUP>224</SUP>Ra) in coastal groundwater and seawater during the summer of 2002 and 2003 in the southern sea of Korea, where harmful dinoflagellate blooms (hereafter red tides) have been occurring every year since 1982. In this region, the amount of submarine groundwater discharge (SGD) is known to be two orders of magnitude higher than the surface runoff. Good correlations of dissolved inorganic nitrogen (DIN) and silicate (DSi) with groundwater-borne <SUP>224</SUP>Ra (half life=3.66days) in the initial red-tide waters of 2002 confirm that the source of these nutrients is SGD. In addition, the DIN/DIP ratios in 2002 and total dissolved nitrogen/phosphorus (TDN/TDP) ratios in 2003 in red-tide waters ranged from 30 to 300, similar to those observed in groundwater. The spatial and temporal variations of nutrients and photosynthetic pigments showed that red tides broke out when DIN or DIP (dissolved inorganic phosphorus) were almost depleted, limiting the growth of diatoms. Thus, our observations reveal that the emergence of harmful dinoflagellate red tides might be facilitated by inter-specific competition of phytoplankton species when inorganic nutrients are limited and dissolved organic nutrients, converted from groundwater-borne nutrients, are sufficient.</P>

A relationship between submarine groundwater borne nutrients traced by Ra isotopes and the intensity of dinoflagellate red-tides occurring in the southern sea of Korea

Lee, Yong-Woo,Kim, Guebuem,Lim, Weol-Ae,Hwang, Dong-Woon Wiley (Blackwell Publishing) 2010 Limnology and oceanography Vol.55 No.1