Red Tide Occurrence Research Articles

위성영상을 활용한 한국 남해의 광학적 특성 연구 : 2013년 8월 발생한 적조 사례를 중심으로

위성영상을 활용한 한국 남해의 광학적 특성 연구 : 2013년 8월 발생한 적조 사례를 중심으로

Monitoring HABs in the shallow Arabian Gulf using a qualitative satellite-based index

ABSTRACTIn this study, a harmful algal bloom (HAB) index, commonly known as a red tide index (RI), was developed and tested using in situ measurements in the shallow Arabian Gulf where periodical occurrence of red tide has been reported. The index is based on a combination of ratio and difference of bands centred at 443, 531, and 547 nm. The index was applied to Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua imagery and compared with other proxies of HABs such as chlorophyll-a (chl-a) concentrations and fluorescence line height (FLH). Validation of the proposed index produced a positive correlation between the index and chlorophyll-a concentration with a determination coefficient (R2) of 0.61. Seasonality analysis of RI indicated that HABs in the Gulf region occur mainly in fall and winter. The inter-annual variations of RI showed similar patterns with the conventional chl-a product. This new index can provide insights into the dynamics of red tides and guidance for mitigation efforts, and assist in establishing an effective and timely forecasting and warning system for red tide.

Ecosystem responses to anthropogenic and natural forcing over the last 100 years in the coastal areas of the East China Sea

Ecosystem changes of the coastal areas of the East China Sea (ECS) during the past 30 years have been characterized by increased productivity and increased occurrences of dinoflagellate red tides; both were commonly attributed to be caused by anthropogenic input of nutrients. However, climate-driven regime shifts were found in the Pacific, but they have not been observed in the ECS owing to the lack of continuous high resolution data. Hence, it is still a challenge to distinguish the influences of anthropogenic activities and climate changes on ECS shelf ecosystem. We compare phytoplankton biomarker (brassicasterol, dinosterol, and alkenones) data of five box cores from the coastal area of the ECS, which afford phytoplankton productivity and community structure records at decadal-scale resolution for the last 100 years. Phytoplankton productivity in all cores increased during the past 50 years, but community structure changes showed different trends. Relative diatom contribution revealed a decreasing trend during the past ca. 50 years in cores DH5-1 and CJ43 collected near the Changjiang Estuary, which were likely caused by increased N/Si and N/P ratios, providing conditions more favorable for dinoflagellates growth. In contrast, the relative diatom contribution increased in cores 32, 34, and DH6-3 further away and south of the Changjiang Estuary, suggesting limited influence of the Changjiang water. Instead, diatom increasing trend is likely caused by increased supply of phosphorus and silicate, as a result of larger Kuroshio intrusion flux and the corresponding strengthened coastal upwelling. Therefore, both anthropogenic activities and climate-driven coastal upwelling have contributed to increased productivities, but these two forcing mechanisms have resulted in contrasting community structure changes at different sites in the coastal area of the ECS.

Impacts of and adaptation to inter-decadal marine climate change in coastal China seas

The coastal China areas stretching from tropical to temperate zone represent major environmental and economic assets. However, knowledge of climate change and its impact in coastal seas, which is very critical for marine resource and risk-management issues, is relatively poor compared with that on land. Here, we show that the coastal China seas experienced a long-term surface warming with a rate of 0.015 °C year−1 and an obvious sea level rise along the coast, particularly along the East China Sea with a rate of more than 3.2 mm year−1 since the late 1950s. The Eurasian atmospheric circulation underwent clearly inter-decadal changes in the past decades due to the tropical ocean thermal changes including warming hiatus and conversely influenced the higher latitude coastal marine conditions through regional air–sea interaction. Marine climate variables including sea surface temperature, sea surface height, and atmospheric cyclonic circulation have formed a favourable condition for phytoplankton blooms such as harmful algae blooms (e.g. red tides) and Enteromorpha prolifera blooms (green tides). These algae blooms could strongly lower oxygen levels in the seawater and have been posing threats for the health of coastal and marine ecosystems since the late 1970s. The impacts and key risks of climate change risks in coastal China seas and the coastal zone are reviewed and analysed as follows: frequent occurrences of red tides and green tides, distribution shifts of marine species and changes in their seasonal behaviour, reduction of coastal habitat, decline of marine ecosystem services, flooding and coastal inundation, seawater intrusion, and threats to coastland community security and marine industries, etc. Furthermore, the accumulated effects of human activity, such as reclamation, sewage discharge, and overfishing, have led to an apparent increase in climate-related vulnerabilities. Adaptation issues and risk-management strategies in response to climate change are discussed and proposed as well.

Relationship between environmental factors and plankton in the Bayuquan Port, Liaodong Bay, China: a five-year study

To understand the relationship between the plankton community and environmental factors and water quality in the Bayuquan Port of Liaodong Bay, China, and investigations were carried out during six different periods (April 2009, April 2010, October 2011, April 2012, October 2012, and April 2013). This area was characterized by high levels of nutrient and suspended solids (SPS) during survey periods, and eutrophication led to the occurrence of red tides in April and October 2012 and April 2013. Our analyses revealed that the plankton communities of Bayuquan Port lacked stability and were affected seriously by external disturbance (e.g., oceanographic engineering and river runoff). Our data indicate that oil, dissolved inorganic nitrogen (DIN), SPS, and chlorophyll a (Chl-a) were key factors that regulated the phytoplankton and zooplankton communities. The partial redundancy analysis (partial RDA) suggested that oil and SPS were the most important environmental variables affecting the phytoplankton community in April 2010 and 2012, whereas DIN concentration played a governing role in zooplankton dynamics. Oil and Chl- a concentrations affected significantly the zooplankton community in October 2012. Therefore, the plankton communities could reflect both dynamic changes in coastal environmental factors and the ongoing eutrophication process caused by anthropogenic activities in this area.

천리안 GOCI영상을 이용한 남해안 적조우심해역 분석

매년 적조가 발생하여 양식어민들에게 막대한 피해를 주고 있으며 발생해역도 남해안을 중심으로 발생되던 패턴에서 전국 연안 해역으로 확대되는 추이를 보이고 있다. 광활한 해양에서 발생되는 적조를 효과적으로 모니터링하기 위해 2010년에 발사된 천리안 위성의 GOCI(Geostationary Ocean Color Imager)영상을 이용한 적조 탐지기술 개발에 관심이 모아지고 있다. 본 연구에서는 남해안 해역에 대해 최근 3년간(2012, 2013, 2014년) 관측된 천리안 GOCI영상을 이용하여 적조해역을 탐지하고 탐지된 해역에 대한 적조발생빈도와 밀도를 분석하였다. 그 결과 3년간 남해안을 대상으로 적조 발생 해역을 추출하고 중첩분석과 밀도분석을 통하여 적조우심해역을 추출하여 제시하였다. 또한 연도별 적조발생 경향은 2012년에 적조 발생규모가 작고 산발적으로 발생하였고, 2013년은 적조 발생해역이 광범위하게 분포하면서 공간적 밀집도도 높게 나타났으며, 2014년의 경우에는 소규모의 적조가 산발적으로 발생하였다. 이처럼 연도별 적조발생의 공간적 분포패턴은 불규칙한 특징을 보였으며 다양하게 변화되고 있음을 알 수 있었다. 하지만 적조발생빈도를 기반으로 핫스팟을 분석한 결과 특정 해역에서는 발생빈도가 꾸준히 증가되고 있어서 천리안 GOCI 영상과 같은 위성영상모니터링 기술을 이용하여 지속적으로 모니터링을 실시함으로써 적조의 움직임을 정확히 예측할 수 있고 이에 따른 방재계획을 체계적으로 수립할 수 있다고 판단된다. The area of red tides occurences, which brings enormous damages every year, have been expanded to the coastal waters across the nation. Regarding to this trend, the development of red tide detection technology by using the GOCI (Geostationary Ocean Color Imager) of COMS lauched in 2010 has been drawn attentions of researchers. This study purposed on analyzing the frequency and density of red tides occurence by using the GOCI for detecting the southern sea, whereas targeted area. The observation has brought over the last three years (2012, 2013, and 2014) before the analysis was conducted. Followingly, the study could be resulted in extracting and revealing the hot spots of the red tides from two of analysis in the overlay and density. The distribution patterns of red tide occurrences according to those observed years has been shown in irregular characteristics and various changes. However, the analysis of hot spots, based on the frequency of the red tide occurrence, has revealed that the frequency of red tide occurences is continuously increased in the specific sea area. Therefore, it is concluded in that the continuous monitoring can contribute to predict accurate movements of red tides, so as establish systematic plans for preventing disasters.

Assessing change of environmental dynamics by legislation in Japan, using red tide occurrence in Ise Bay as an indicator

Tokyo Bay, Ise Bay, and the Seto Inland Sea are the total pollutant load control target areas in Japan. A significant correlation between the incidence of red tides and water quality has been observed in the Seto Inland Sea (Honjo, 1991). However, while red tides also occur in Ise Bay and Tokyo Bay, similar correlations have not been observed. Hence, it is necessary to understand what factors cause red tides to effectively manage these semi-closed systems. This study aims to investigate the relationship between the dynamics of the Red Tide Index and nitrogen regulation as well as phosphorus regulation, even in Ise Bay where, unlike Tokyo Bay, there are few observation items, by selecting a suitable objective variable. The introduction of a new technique that uses the Red Tide Index has revealed a possibility that the total pollution load control has influenced the dynamics of red tide blooms in Ise Bay.

Remote-sensing observations of Typhoon Soulik (2013) forced upwelling and sediment transport enhancement in the northern Taiwan Strait

The Taiwan Strait plays an important role in water and sediment exchange between the East China Sea and the South China Sea. On 13 July 2013, Typhoon Soulik crossed the Taiwan Strait, causing a significant impact on the strait’s marine system. In this article, we document the use of remote-sensing data to study this impact by comparing sea surface temperature (SST), spatial distributions and concentrations of chlorophyll (Chl-a), and total suspended matter (TSM) in the strait over different time periods. During and after the typhoon, the TSM of the waters near the Minjiang estuary dramatically increased, while Chl-a and SST significantly decreased. To the southeast of Pingtan Island, the SST decreased and Chl-a significantly increased, causing strong upwelling that lasted eight to ten days. To the northwest of Taiwan Island, Chl-a and the TSM of the coastal waters dramatically increased. The strong cyclonic wind-stress of the typhoon enhanced heat exchange between the water and the atmosphere, and a large amount of rainfall and run-off significantly decreased the SST. During the typhoon, the increased sediment discharged into the strait by rivers, and the re-suspension of seafloor sediment, increased the concentration of TSM in the coastal waters. Seawater with relatively high sediment concentration was transported to the middle of the strait after being carried by wind-induced flows. In the waters near the typhoon’s path, especially in the upwelling area, nutrient-rich bottom water stirred by the typhoon promoted an outbreak of aquatic organisms and significantly increased the probability of a red tide occurrence.

인공위성을 통한 해양·기상자료를 이용한 적조발생예보

Red tide occurs every year in the coastal seas of the South Korea, This phenomena has become a national issue of environmental and economic damage. In this study, we analyzed a suitable conditions to occur the red tide by using oceanic and atmospheric data during 10 years, These factors were applied to predict the red tide occurrence from 2012 to 2014. As a result, in 2012 and 2013, it is able to alarm the red tide occurrence before 6∼11 days. However, in compared to the normal year and 2014, the prediction of red tide occurrence were less accurate because of more precipitation, short sunshine duration, low temperature waters. Therefore, it is necessary to further investigate the impact of sunshine duration(Solar radiation) on red tide occurrence, it is more necessary to consider the comprehensive analysis using additional oceanic and atmospheric factors.

不同营养盐条件下东海赤潮高发区围隔生态系内多胺的变化

PDF HTML阅读 XML下载 导出引用 引用提醒 不同营养盐条件下赤潮高发区围隔生态系内多胺的变化 DOI: 10.5846/stxb201306081458 作者: 作者单位: 中国科学院海洋研究所,中国科学院海洋研究所,中国科学院海洋研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划资助项目(2010CB428701);国家自然科学基金项目(40976047,41276118) Effects of nutrient on polyamines variation in the mesocosm in the East China Sea Author: Affiliation: Institute of Oceanology, Chinese Academy of Sciences,Institute of Oceanology, Chinese Academy of Sciences, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在东海赤潮爆发区域运用围隔生态系实验方法,研究了不同营养盐条件下围隔生态系内多胺浓度变化。结果表明:2010年选用东海原甲藻赤潮爆发处海水,东海原甲藻是各围隔生态系内主要优势种,没有种群演替现象发生。两种营养盐添加方式下各围隔内精胺浓度维持较高水平,都呈现先波折下降后波折上升的趋势,与东海原甲藻的生长变化正好相反;各围隔内腐胺浓度水平较高,变化起伏较大,其中有两个实验组腐胺整体变化趋势与东海原甲藻生长趋势类似;所有围隔内亚精胺浓度最低,波动较小。2011年取用中肋骨条藻赤潮爆发处海水,所有围隔生态系内优势种都发生了从中肋骨条藻到东海原甲藻的演替。各围隔生态系内腐胺浓度最高,在中肋骨条藻生长初期腐胺浓度下降,随着中肋骨条藻的生长有所上升,实验后期随着东海原甲藻的生长又整体呈现出下降趋势;各实验组精胺浓度较低,在中肋骨条藻消亡东海原甲藻出现的种群演替期间,都呈现出较大波动;各围隔内亚精胺浓度较低,在整个种群演替过程中没有明显的变化。围隔生态系中补充营养盐,通过对浮游植物生长的影响,间接影响围隔生态系内的多胺变化。 Abstract:We investigated the effects of different nutrients on the concentration of polyamines by mesocosm experiment in an area of frequent red tide occurrence in the East China Sea. As essential components of cellular regulation, polyamines are synthesized by algae and secreted into the surrounding waters, particularly during the decomposition period following a bloom, and may thus drive the succession of future blooms. In 2010, where blooms of the dinoflagellate Prorocentrum donghaiense occurred, it was the dominant species, the nutrient content of the water was low, and there was no evidence of species succession in any of the mesocosms. According to our results, P. donghaiense growth period length and maximal biomass would be enhanced with increased levels of nutritive salt, specifically PO4. Polyamines were significantly higher in mesocosms to which nutritive salt was added than in the control mesocosm. Spermine levels showed a wavelike, inverse trend decreasing with P. donghaiense growth and increasing with its decline. Putrescine concentrations were higher than spermine, fluctuated significantly, and were positively associated with growth of P. donghaiense in every mesocosm except the control. Spermidine had the lowest concentration of all the polyamines and fluctuated the least in all mesocosms. In 2011, we detected a succession in species from Skeletonema costatum to P. donghaiense in all mesocosms where S. costatum blooms occurred. The nutrient content of the seawater, specifically PO4, was sufficient to sustain dinoflagellate populations. However, our results suggest that the addition of NO3 and SiO3 would prolong the S. costatum growth period, and increase its maximal biomass. When just NO3 concentrations were increased, the absorption of PO4 increased significantly, and S. costatum died off more quickly. This suggests that an influx of NO3 could initiate an earlier turnover to P. donghaiense. When more NO3 was added, the maximal biomass of P. donghaiense was higher. If nutrients are added before S. costatum die-off, the rate of turnover might be slower, delaying the appearance of P. donghaiense. In every mesocosm in the second year, putrescine concentration was the most abundant polyamine. In the early growth stages of S. costatum, the level of putrescine initially decreased. Levels then increased with S. costatum growth, and fell again with P. donghaiense growth in the later stages of the experiment. We suggest that S. costatum and P. donghaiense absorb exogenous putrescine, causing it to decrease in the mesocosms. In every mesocosm, spermine concentrations were low and fluctuated greatly during the succession. Similarly, the level of spermidine was low in all microcosms; however, it had no obvious fluctuation during succession. Variation in nutrients affected concentrations of polyamines indirectly by influencing phytoplankton growth. From this 2-year mesocosm experiment, we found that as both S. costatum and P. donghaiense decompose, they release polyamines. We refer to this as the dispersion period. We also found that during growth periods both species metabolize and secrete polyamines. In conditions of lower nutrient availability, exogenous polyamines could stimulate P. donghaiense growth. Algal enzymes catalyze the conversion of polyamines, and thus the growth and decomposition of these dinoflagellates during times of bloom results in significant polyamine fluctuations. 参考文献 相似文献 引证文献

Long-term trends in the occurrence of red tides in the Seto Inland Sea, Japan

Long-term trends in the occurrence of red tides in the Seto Inland Sea, Japan

Environment impacts of undulated surf clam dredging operation off Prachaup Kirikharn province, Thailand

Environment impacts of experimental dredging operations for the undulated surf clam, Paphia sp. around Paknam-Pran and adjacent coastal areas (Amphur Pranburi and Amphur Sam-roi-yod, Prachaup Khirikhan Province, Thailand) were investigated in collaboration with Department of Fisheries, Thailand. Data were collected on physical parameters from water samples at surface layer (30 cm below sea surface), and nutrient parameters from surface as well as overlying water (50 cm above bottom sediment level). Results show that water quality changed by dredging operation in the following ways: the most significant impact was increase in Total Suspended Solids (TSS), and consequently, decrease in water transparency. Dissolved oxygen concentration was marginally higher in several stations after dredging, possibly due to disturbance caused by dredge boat propellers. Concentrations of Ammonium-Nitrogen (NH4+-N), Silicate-Silicon (Si(OH)4-Si) and Orthophosphate-Phosphorus (PO43--P) marginally increased in almost all stations after dredging. There is a possibility that increase in nutrient concentration may lead to occurrence of red tide during and after the surf clam dredge fishing season.

천리안 위성 GOCI 영상을 이용한 남해안의 시공간적 적조변화 분석

This study deals with red tide detection by using the remote sensing imagery from the Geostationary Ocean Color Imager (GOCI), the world`s first geostationary orbit satellite, around the southern coast of Korea where the most severe red tide occurred recently. The red tide zone was determined by the available data selection from the GOCI imagery during the period of red tide occurrence and also the severe red tide zone was detected through the spatial analysis by temporal change out of the red tide zone. This study results showed that the coast in the vicinity of the Hansan and Yokji in Tongyeong-si was classified into the severe red tide zone, and that the red tide was likely to spread from the coast of Hansan and Yokji to the one of Sanyang-eub. In addition, the comparative analysis between the area of red tide occurrence, the prevention activities of Gyeongsangnam-do provincial government and the amount of the damage cost over time showed close correlation among them. It is still early to conclude that the study is showing the severe red tide zone and the spread path exactly due to various factors for red tide occurrence and activities. In order to improve the reliability of the results, the more data analysis is required.

Assessing seawater quality with a variable fuzzy recognition model

With the rapid development of the marine economy industry, human exploitation of marine resources is increasing, which is contributing to the growing trend of eutrophication and frequent occurrence of red tide. Accordingly, investigations of seawater quality have attracted a great deal of attention. This study was conducted to construct a seawater environmental quality assessment model based on the variable fuzzy recognition model. The uncertainty and ambiguity of the seawater quality assessment were then considered, combining the monitoring values of evaluation indicators with the standard values of seawater quality. Laizhou Bay was subsequently selected for a case study. In this study, the correct variable model for different parameters was obtained according to the linear and nonlinear features of evaluation objects. Application of the variable fuzzy recognition model for Laizhou Bay, water quality evaluation and comparison with performance obtained using other approaches revealed that the generated model is more reliable than traditional methods, can more reasonably determine the water quality of various samples, and is more suitable for evaluation of a multi-index, multi-level, nonlinear marine environment system; accordingly, the generated model will be an effective tool for seawater quality evaluation.

Distribution of Sand Particles Along the Shoreline of Lake Biwa in Shiga Prefecture and Considerations from Lake Biwa and Seto Inland Sea, Japan

The development of sand littoral zones is critical to supporting specific species in lakes and oceans. The construction of dams on rivers changes the distribution of sediments in littoral zones, and the relationship between dam construction on rivers, the inflow of small particles and increased eutrophication and red tide occurrences was demonstrated for Lake Biwa using public data. Many dams were constructed on rivers around Lake Biwa after the Second World War, and the old and new Araizeki dams were constructed on the out flowing Seta River, restricting flow and increasing the tendency of small particles to be deposited on the floor of Lake Biwa. Inouchi 6 reported the distribution of seafloor sediment particle sizes in the Seto Inland Sea. Inouchi showed several fan-shaped distributions of sediment particles centered at the mouths of rivers. After many dams were constructed on the rivers in the period following the Second World War, particles smaller than Mdφ 4 to 6 were thought to increase in the rivers, and these smaller particles were deposited farther offshore from the river mouth if tidal currents were faster than 0.5 to 1.0 knots. Areas of the Seto Inland Sea in 1975 that were affected by silting and subsequent red tide blooms include Hiroshima Bay, Hiuti-nada, Harima-nada and Osaka Bay. These findings and similar patterns between the Seto Inland Sea and Lake Biwa support my hypothesis that the influx of mud due to the construction of dams brings about eutrophication and red tides.

Relationship between the number of cysts that germinate and the occurrence of red tides in the inner part of the Ariake Sea

Relationship between the number of cysts that germinate and the occurrence of red tides in the inner part of the Ariake Sea

조선왕조실록의 적조(HABs) 고찰

조선왕조실록을 통해 14세기 말부터 19세기 초까지 적조(HABs) 발생상을 분석하였다. 적조기사는 모두 81건으로 표로 정리하고, 적조지도를 구축하였다. 해역별 발생횟수는 남해 62건, 동해 50건 그리고 황해 22건으로 나타났다. 남해와 동해에 접한 경상도에서는 82건으로 가장 많았다. 경상남도에서 함경북도까지의 적조발생은 두 가지 형태로 나타났는데 첫 번째는 3월 강원도에서 시작되어 4월 함경남도에서 발생이 증가하고 5, 6월에는 중심이 함경북도로 북상하는 형태이다. 두 번째는 8월 경상남도를 중심으로 발생하다 9월에는 경상북도에서 발생이 증가하는 형태이다. 월별 발생 수는 8월이 가장 높았다. 그 외는 대부분 4~9월에 나타났다. 그 중 조개류를 먹고 인명 피해가 발생한 사례는 2~6월 진해, 거제, 통영에서 나타났다. 수산물 피해는 7~9월 경상도연안 전반에서 나타났다. 적조가 대규모로 발생한 시기는 1394~1451년, 1654~1706년으로 나타났고, 적조의 소규모 발생은 1493~1534년, 1588~1609년 이었으며, 공통적으로 홀수 해(1399, 1403, 1413, 1681년)에 대발생을 보였다. We investigated the occurrence of red tide, harmful algal blooms(HABs), at the end of 14th century until the beginning of 19th century recorded in the Annals of the Joseon Dynasty, which are the authentic and encyclopedic annual records of the Joseon Dynasty of Korea. In total, 81 cases of HABs are recorded in the annals for which authors draw a table and maps. The number of HABs occurrence at each sea is as follows: 68 times at the South Sea; 50 times at the East Sea; and 23 times at the Yellow Sea. A region hit by red tide most frequently was Gyeongsang-do Province (over 80 times), which borders on both the South Sea and the East Sea. HABs written in the annals follow two distinctive occurrence patterns. The first pattern shows red tide started at Gangwon-do Province in March, spread north to Hamgyeongnam-do Province in April, and moved further north to Hamgyeongbuk-do Province in May and June. On the other hand, the second pattern shows red tide occurred in Gyeongsangnam-do Province in August and then expanded north to Gyeongsangbuk-do Province in September. HABs generally happened from March to September, culminating in August. Paralytic shellfish poisoning incidents involving human deaths were reported in Jinhae, Geoje and Tongyeong, occurring February to June. Fish mortality increased throughout Gyeongsang-do Province from July to September. HABs occurred on an extensive scale from 1394 to 1451 and again from 1654 to 1706. HABs also occurred on a lesser scale from 1493 to 1534 and again from 1588 to 1609. In general, vast HABs occurred in odd years (1399, 1403, 1413 and 1681).

The red-tide ciliate Mesodinium rubrum in Korean coastal waters

Mesodinium rubrum is a cosmopolitan red tide ciliate and also an obligate mixotroph requiring cryptophycean prey to sustain photosynthesis and growth. Bloom formation by M. rubrum has been recorded in Korea since early 1980s. As part of these records, 40 cases of M. rubrum outbreaks in Korean coastal waters during last three decades were archived in Red Tide Monitoring Dataset of the National Fisheries Research and Development Institute of Korea. Distribution and ecology of Korean M. rubrum populations were first reported in an article about the red tide occurrence and species succession in Jinhae Bay (Park et al., 1988). The first ever temperate strain of M. rubrum was established from Gomso Bay, Korea in 2002 (Yih et al., 2004a), which was followed by a series of research on the biological and ecophysiological characteristics of the ciliate strain MR-MAL01 and then by the first successful cultivation of a DSP dinoflagellate, Dinophysis acuminata strain DA-MAL01 in 2006. Here, we summarize occurrence of M. rubrum in Korean coastal waters encompassing from the national wide long-term monitoring program to the spatiotemporally fine-scaled regional studies. In parallel, we review previous ecophysiological researches using Korean M. rubrum cultures and finally added our perspectives on the future directions of M. rubrum research in Korea.

Physical–biological coupling induced aggregation mechanism for the formation of high biomass red tides in low nutrient waters

Port Shelter is a semi-enclosed bay in northeast Hong Kong where high biomass red tides are observed to occur frequently in narrow bands along the local bathymetric isobars. Previous study showed that nutrients in the Bay are not high enough to support high biomass red tides. The hypothesis is that physical aggregation and vertical migration of dinoflagellates appear to be the driving mechanism to promote the formation of red tides in this area. To test this hypothesis, we used a high-resolution estuarine circulation model to simulate the near-shore water dynamics based on in situ measured temperature/salinity profiles, winds and tidal constitutes taken from a well-validated regional tidal model. The model results demonstrated that water convergence occurs in a narrow band along the west shore of Port Shelter under a combined effect of stratified tidal current and easterly or northeasterly wind. Using particles as dinoflagellate cells and giving diel vertical migration, the model results showed that the particles aggregate along the convergent zone. By tracking particles in the model predicted current field, we estimated that the physical–biological coupled processes induced aggregation of the particles could cause 20–45 times enhanced cell density in the convergent zone. This indicated that a high cell density red tide under these processes could be initialized without very high nutrients concentrations. This may explain why Port Shelter, a nutrient-poor Bay, is the hot spot for high biomass red tides in Hong Kong in the past 25 years. Our study explains why red tide occurrences are episodic events and shows the importance of taking the physical–biological aggregation mechanism into consideration in the projection of red tides for coastal management.

Forecasting Red Tide using Ensemble Method

Red tide is a temporary natural phenomenon involving harmful algal blooms (HABs) in company with a changing sea color from normal to red or reddish brown, and which has a bad influence on coast environments and sea ecosystems. Recent wide spread and persistent HABs give seriously impact public health and the economy of fisheries along coasts of many countries, since it mainly kills fish mainly and results in occasional shellfish poisoning. If we can predict the occurrence of red tide, we will be able to minimize the damage of HABs by a quick preparation of mitigation activity. To enhance the automatic forecast of red tide, this paper proposes a red tide prediction method that uses ensemble method. The proposed method can improves the precision of forecast results since the ensemble classifier is enhanced by optimal data of the proposed preprocessing.