The intertidal macrobenthic fauna of the Hatakejima Experimental Field, Wakayama Prefecture, Japan, in 2019

ファイル差し替え（2021-05-17）Hatakejima Experimental Field is located in Tanabe Bay, Wakayama Prefecture, Japan, which is composed of Hatakejima Island and Komarujima Islet, connected to the former in low tide. Hatakejima Island was purchased by Kyoto University and was designated as the “Hatakejima Experimental Field” in 1968. The year 2019 marks the 50th year of the long-term surveys that have been formally conducted on the experimental field since 1969 (i.e., the Century of Research Project). We conducted a field survey to record the macrobenthic fauna of the experimental field in 2019. A total of 168 species of 11 phyla were recorded in this survey. In each phylum, the number of species is listed as follows in descending order: Mollusca (78 spp.), Arthropoda (27 spp.), Echinodermata (23 spp.), Annelida (21 spp.), Cnidaria (7 spp.), Porifera (3 spp.), Nemertea (3 spp.), Platyhelminthes (2 spp.), Chordata (2 spp.), Bryozoa (1 sp.), and Hemichordata (1 sp.). We also recorded and discussed the influence of recent environmental changes around the Hatakejima Experimental Field. Tropical sea urchin species disappeared in the winter of 2017–2018 following the large meander of the Kuroshio Current, which led to decreasing water temperatures. The population of the seagrass Zostera japonica drastically decreased on the western sandy shore of the island in 2019, most likely because of two big typhoons in September 2018. We must conduct continuous observations to aid the recovery of seagrass-associated communities and protect the experimental field to keep high biodiversity of macrobenthic fauna in the future

Grandidierella japonica (Amphipoda: Aoridae): a non-indigenous species in a Po delta lagoon of the northern Adriatic (Mediterranean Sea)

The introduction and spread of non-indigenous species is one of the main threats to biodiversity of aquatic ecosystems and it is becoming an increasing problem for the international scientific community. Aquaculture and related activities are recognized as one of the most important drivers of non-indigenous species in the Mediterranean. Grandidierella japonica Stephensen, 1938 is an aorid amphipod species native of Japan. This species had previously only been reported a few times outside the Pacific region, in particular from coastal waters of England and French Atlantic coasts. A population of the non-indigenous amphipod G. japonica, has been detected in the Sacca di Goro, a Po delta lagoon of the northern Adriatic Sea (Italy), representing the first record of this species in the Mediterranean Sea. Adults of both sexes and juveniles were collected in muddy sediments reaching high densities. We examined 24 specimens: 8 adult males, 12 females, and 4 undifferentiated juveniles. Our specimens displayed a variability in the position of teeth of male gnathopod 1. Likely vectors for this introduction are the commercial shellfish transplants, mainly oyster farming. The finding of a reproducing population of G. japonica suggests that the species has become well established in the Sacca di Goro. This finding also seems to be particularly relevant for the improvement on the knowledge of Mediterranean biodiversity and threats

Recent discovery of Paranthura japonica Richardson, 1909 (Crustacea: Isopod: Paranthuridae) in European marine waters (Arcachon Bay, Bay of Biscay)

The Asiatic isopod Paranthura japonica Richardson, 1909 was collected in 2007 in Arcachon Bay (SW France), where the species occurs in a variety of habitats, both in the intertidal and at shallow depths. This species, native to the Sea of Japan, may have been accidentally introduced in Arcachon Bay with oyster transfers or as fouling on ship hulls

황해 연안지역 퇴적물 내 잔류성독성물질의 시공간 분포 및 대형저서동물 군집에 대한 영향

학위논문 (박사) -- 서울대학교 대학원 : 자연과학대학 지구환경과학부, 2021. 2. 김종성.Sediments in the coastal areas of the Yellow Sea have been contaminated by persistent toxic substances (PTSs) over the last 30 years. This study evaluated the spatiotemporal distribution of classic and emerging PTSs in sediment and their impact on the macrofaunal community in the coastal areas of the Yellow Sea. PTSs included polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), polychlorinated biphenyls (PCBs), metals, emerging PTS (styrene oligomers (SOs), emerging-PAHs (E-PAHs), and halogenated-PAHs (Hl-PAHs). The distribution of PTSs varied in relation to chemical and station, with that of PAHs being generally high. PAH concentrations in Nantong, Huludao, and Qinhuangdao (China) present potential risks to aquatic organisms. Over the last decade, PAH contamination has declined in Korea, while that of PAHs in general has increased in China. Thus, PTS contamination is likely ongoing with high potential risk, especially in China. Historical records of classic and emerging PTSs over the 100 years showed that contamination of both classic and emerging PTSs was high from the 1970s to 1990s. Fluxes of classic and emerging PTSs showed a similar trend to concentrations of PTSs; however, since the 2000s, the rate of decrease has been relatively low, indicating the continuous input of PTSs to the Yellow Sea. The impact of PTSs has been low, despite the relatively high concentrations of classic and emerging PTSs in hotspots. The macrofaunal community inhabiting the upper intertidal zone, estuaries, and coastal areas was more impacted by salinity, sediment grain size, and chlorophyll-a, rather than PTSs. However, the great potential ecological risk of PTSs was found in some areas, which suggested that continuous monitoring is required. Overall, the contamination by sedimentary PTSs in the coastal areas of the Yellow Sea has decreased compared to the past; however, contamination remains high in certain areas. The impacts of PTSs on the macrofaunal community were weak, despite the high PTS concentrations in some areas. In conclusion, This study provides baseline information on PTS contamination and ecological impacts, suggesting that selecting priorities for pollution management and implementation of pollution reduction policies in Korea and China are necessary.황해 연안지역 퇴적물은 지난 30여년간 잔류성오염물질에 의해 오염되어 왔다. 본 연구에서는 최초로 황해 전체 연안지역 퇴적물 내 기존 (다환방향족탄화수소, 알킬페놀, 폴리염화비페닐, 중금속) 및 신규 (스티렌올리고머와 아미노, 알킬 또는 할로겐으로 치환된 다환방향족탄화수소) 잔류성오염물질의 시공간분포와 대형저서동물 군집에 미치는 영향을 평가하였다. 잔류성오염물질의 분포는 화합물과 정점에 따라 다양하게 나타났고, 다환방향족탄화수소의 농도가 상대적으로 높게 나타났다. 특히, 중국의 후루다오, 친황다오, 난통지역 내 다환방향족탄화수소의 농도는 수 생태계에 잠재적 위해성을 가지는 것으로 확인되었다. 지난 10여년간 한국에서 다환방향족탄화수소 농도는 감소하였지만, 중국에서는 유입원의 변화와 함께 최근 더 높은 농도가 검출되었다. 연대가 측정된 주상퇴적물 분석한 결과, 지난 100여년간 기존 및 신규 잔류성오염물질이 존재하였고, 1970년대부터 1990년대에 가장 높은 농도로 분포한 것이 확인되었다. 잔류성오염물질의 유입량은 1990년대 이후에도 상대적으로 높게 나타나, 황해 연안지역의 오염이 지속되고 있음을 시사하였다. 잔류성오염물질에 의한 영향은 농도나 지역에 관계없이 상대적으로 작다는 것이 확인되었다. 상부조간대, 하구, 연안 지역에 서식하는 대형저서동물 군집은 환경요인 중 잔류성오염물질 보다 염분, 퇴적물 입자크기에 가장 영향을 받았다. 하지만 일부 지역에서 잔류성오염물질의 잠재적 위험도가 높게 나타나 지속적인 관찰이 요구된다. 이상의 연구결과를 종합 요약하면, 첫째, 황해 연안 퇴적물내 잔류성오염물질은 과거에 비해 최근 감소했으나, 일부 지역에서 여전히 높은 오염도를 보였고, 둘째, 대형저서동물의 군집구조는 잔류성오염물질보다는 서식지 내 물리 화학적 환경요인에 의해 더 영향을 받는 것으로 나타났다. 결과적으로, 본 연구는 황해 연안 지역의 오염과 생태학적 영향에 대한 정보를 제공하며, 향후 한국과 중국의 오염관리를 위한 우선순위 선택 및 오염감소 정책 실행이 필요함을 시사한다.ABSTRACT I TABLE OF CONTENTS II LIST OF ABBREVIATIONS VI LIST OF TABLES IX LIST OF FIGURES XII CHAPTER. 1. Introduction 1 1.1. Background 2 1.2. Objectives 10 CHAPTER. 2. Distributions Of Persistent Organic Contaminants In Sediments And Their Potential Impact On Macrobenthic Faunal Community Of The Geum River Estuary And Saemangeum Coast, Korea 12 2.1. Introduction 13 2.2. Materials and Methods 15 2.2.1. Sampling strategy 15 2.2.2. Analyses of PTSs and carbon stable isotope ratio 15 2.2.3. Macrobenthic fauna analysis 19 2.2.4. Quality assurance and quality control 19 2.2.5. Data analysis 19 2.3. Results and Discussion 21 2.3.1. Spatial distribution of persistent organic contaminants 21 2.3.2. Composition and sources of persistent organic contaminants 26 2.3.3. Sources and distribution of organic matter 31 2.3.4. Association of POCs contamination to the macrofaunal community 35 2.4. Summary 42 CHAPTER. 3. Macrozoobenthic community responses to sedimentary contaminations by anthropogenic toxic substances in the Geum River Estuary, South Korea 2014 43 3.1. Introduction 44 3.2. Materials and Methods 47 3.2.1. Study area and sampling 47 3.2.2. PTS analyses 49 3.2.3. Environment parameters and macrobenthic fauna analyses 53 3.2.4. Data analyses 53 3.3. Results and Discussion 55 3.3.1. Spatiotemporal distributions of metals and the metalloid 55 3.3.2. Spatiotemporal distributions of PAHs and APs 66 3.3.3. Spatiotemporal patterns of macrofaunal assemblages 72 3.3.4. Key factors influencing the spatiotemporal pattern of macrofaunal assemblages 76 3.4. Summary 83 CHAPTER. 4. Large-Scale Monitoring And Ecological Risk Assessment Of Persistent Toxic Substances In Riverine, Estuarine, And Coastal Sediments Of The Yellow And Bohai Seas 84 4.1. Introduction 85 4.2. Materials and Methods 89 4.2.1. Study area and sampling 89 4.2.2. Chemicals and reagents 92 4.2.3. PTSs analyses 94 4.2.4. TOC, TN, and stable isotopes analyses 97 4.2.5. Positive matrix factorization receptor model 98 4.2.6. Macrobenthic fauna analysis 99 4.2.7. Data analyses 99 4.3. Results and Discussion 100 4.3.1. Distributions of PTSs in sediments of Yellow and Bohai seas 100 4.3.2. Assessment of potential ecological risks 108 4.3.3. Compositions and sources of PTSs 109 4.3.4. PTSs distributions by land-use types 117 4.3.5. Comparison of PTSs contaminations between 2008 and 2018 123 4.3.6. Macrobenthic fauna community 127 4.4. Summary 130 CHAPTER. 5. Historical Sedimentary Record And Flux Of Classic And Emerging Persistent Toxic Substances In Intertidal Sediment Cores From The Yellow And Bohai Seas 131 5.1. Introduction 132 5.2. Materials and Methods 135 5.2.1. Sampling 135 5.2.2. Target chemicals 137 5.2.3. Analyses of persistent toxic substances 137 5.2.4. Sediment dating and PTSs flux 142 5.2.5. Macrobenthic fauna analysis 145 5.2.6. Data analyses 145 5.3. Results and Discussion 146 5.3.1. Concentrations and fluxes of classic PTSs 146 5.3.2. Concentrations and fluxes of emerging PTSs 151 5.3.3. Compositional profiles and sources of PTSs 154 5.3.4. Deposition flux and mass inventory 162 5.3.5. Macrobenthic fauna community 164 5.4. Summary 167 CHAPTER. 6. Conclusions 168 6.1. Summary 169 6.2. Environmental implications and Limitations 177 6.3. Future Research Directions 184 BIBLIOGRAPHY 186 ABSTRACT (IN KOREAN) 208 APPENDIX 209Docto

Reviews and syntheses: Biological Indicators of Oxygen Stress in Water Breathing Animals

Abstract. Anthropogenic warming and nutrient over-enrichment of our oceans have resulted in significant, and often catastrophic, reductions in dissolved oxygen (deoxygenation). Stress on water-breathing animals from this deoxygenation has been shown to occur at all levels of biological organization: cellular; organ; individual; species; population; community; and ecosystem. Most climate forecasts predict increases in ocean deoxygenation, thus it is essential to develop reliable biological indicators of oxygen stress that can be used by regional and global oxygen monitoring efforts to detect and assess the impacts of deoxygenation on ocean life. This review focuses on indicators of low-oxygen stress that are manifest at different levels of biological organization and at a variety of spatial and temporal scales. We compare particular attributes of these indicators to the dissolved oxygen threshold of response, time-scales of response, sensitive life stages and taxa, and the ability to scale the response to oxygen stress across levels of organization. Where there is available evidence, we discuss the interactions of other biological and abiotic stressors on the biological indicators of oxygen stress. We address the utility, confounding effects, and implementation of the biological indicators of oxygen stress for both research and societal applications. Our hope is that further refinement and dissemination of these oxygen stress indicators will provide more direct support for environmental managers, fisheries and mariculture scientists, conservation professionals, and policy makers to confront the challenges of ocean deoxygenation. An improved understanding of the sensitivity of different ocean species, communities and ecosystems to low oxygen stress will empower efforts to design monitoring programs, assess ecosystem health, develop management guidelines, track conditions, and detect low-oxygen events

Microbial community functioning at hypoxic sediments revealed by targeted metagenomics and RNA stable isotope probing

Microorganisms are instrumental to the structure and functioning of marine ecosystems and to the chemistry of the ocean due to their essential part in the cycling of the elements and in the recycling of the organic matter. Two of the most critical ocean biogeochemical cycles are those of nitrogen and sulfur, since they can influence the synthesis of nucleic acids and proteins, primary productivity and microbial community structure. Oxygen concentration in marine environments is one of the environmental variables that have been largely affected by anthropogenic activities; its decline induces hypoxic events which affect benthic organisms and fisheries. Hypoxia has been traditionally defined based on the level of oxygen below which most animal life cannot be sustained. Hypoxic conditions impact microbial composition and activity since anaerobic reactions and pathways are favoured, at the expense of the aerobic ones. Naturally occurring hypoxia can be found in areas where water circulation is restricted, such as coastal lagoons, and in areas where oxygen-depleted water is driven into the continental shelf, i.e. coastal upwelling regions. Coastal lagoons are highly dynamic aquatic systems, particularly vulnerable to human activities and susceptible to changes induced by natural events. For the purpose of this PhD project, the lagoonal complex of Amvrakikos Gulf, one of the largest semi-enclosed gulfs in the Mediterranean Sea, was chosen as a study site. Coastal upwelling regions are another type of environment limited in oxygen, where also formation of oxygen minimum zones (OMZs) has been reported. Sediment in upwelling regions is rich in organic matter and bottom water is often depleted of oxygen because of intense heterotrophic respiration. For the purpose of this PhD project, the chosen coastal upwelling system was the Benguela system off Namibia, situated along the coast of south western Africa. The aim of this PhD project was to study the microbial community assemblages of hypoxic ecosystems and to identify a potential link between their identity and function, with a particular emphasis on the microorganisms involved in the nitrogen and sulfur cycles. The methodology that was applied included targeted metagenomics and RNA stable isotope probing (SIP). It has been shown that the microbial community diversity pattern can be differentiated based on habitat type, i.e. between riverine, lagoonal and marine environments. Moreover, the studied habitats were functionally distinctive. Apart from salinity, which was the abiotic variable best correlated with the microbial community pattern, oxygen concentration was highly correlated with the predicted metabolic pattern of the microbial communities. In addition, when the total number of Operational Taxonomic Units (OTUs) was taken into consideration, a negative linear relationship with salinity was identified (see Chapter 2). Microbial community diversity patterns can also be differentiated based on the lagoon under study since each lagoon hosts a different sulfate-reducing microbial (SRM) community, again highly correlated with salinity. Moreover, the majority of environmental terms that characterized the SRM communities were classified to the marine biome, but terms belonging to the freshwater or brackish biomes were also found in stations were a freshwater effect was more evident (see Chapter 3). Taxonomic groups that were expected to be thriving in the sediments of the Benguela coastal upwelling system were absent or present but in very low abundances. Epsilonproteobacteria dominated the anaerobic assimilation of acetate as confirmed by their isotopic enrichment in the SIP experiments. Enhancement of known sulfate-reducers was not achieved under sulfate addition, possibly due to competition for electron donors among nitrate-reducers and sulfate-reducers, to the inability of certain sulfate-reducing bacteria to use acetate as electron donor or to the short duration of the incubations (see Chapter 4). Future research should focus more on the community functioning of such habitats; an increased understanding of the biogeochemical cycles that characterize these hypoxic ecosystems will perhaps allow for predictions regarding the intensity and direction of the cycling of elements, especially of nitrogen and sulfur given their biological importance. Regulation of hypoxic episodes will aid the end-users of these ecosystems to possibly achieve higher productivity, in terms of fish catches, which otherwise is largely compromised by the elevated hydrogen sulfide concentrations

Microbial community functioning at hypoxic sediments revealed by targeted metagenomics and RNA stable isotope probing

Microorganisms are instrumental to the structure and functioning of marine ecosystems and to the chemistry of the ocean due to their essential part in the cycling of the elements and in the recycling of the organic matter. Two of the most critical ocean biogeochemical cycles are those of nitrogen and sulfur, since they can influence the synthesis of nucleic acids and proteins, primary productivity and microbial community structure. Oxygen concentration in marine environments is one of the environmental variables that have been largely affected by anthropogenic activities; its decline induces hypoxic events which affect benthic organisms and fisheries. Hypoxia has been traditionally defined based on the level of oxygen below which most animal life cannot be sustained. Hypoxic conditions impact microbial composition and activity since anaerobic reactions and pathways are favoured, at the expense of the aerobic ones. Naturally occurring hypoxia can be found in areas where water circulation is restricted, such as coastal lagoons, and in areas where oxygen-depleted water is driven into the continental shelf, i.e. coastal upwelling regions. Coastal lagoons are highly dynamic aquatic systems, particularly vulnerable to human activities and susceptible to changes induced by natural events. For the purpose of this PhD project, the lagoonal complex of Amvrakikos Gulf, one of the largest semi-enclosed gulfs in the Mediterranean Sea, was chosen as a study site. Coastal upwelling regions are another type of environment limited in oxygen, where also formation of oxygen minimum zones (OMZs) has been reported. Sediment in upwelling regions is rich in organic matter and bottom water is often depleted of oxygen because of intense heterotrophic respiration. For the purpose of this PhD project, the chosen coastal upwelling system was the Benguela system off Namibia, situated along the coast of south western Africa. The aim of this PhD project was to study the microbial community assemblages of hypoxic ecosystems and to identify a potential link between their identity and function, with a particular emphasis on the microorganisms involved in the nitrogen and sulfur cycles. The methodology that was applied included targeted metagenomics and RNA stable isotope probing (SIP). It has been shown that the microbial community diversity pattern can be differentiated based on habitat type, i.e. between riverine, lagoonal and marine environments. Moreover, the studied habitats were functionally distinctive. Apart from salinity, which was the abiotic variable best correlated with the microbial community pattern, oxygen concentration was highly correlated with the predicted metabolic pattern of the microbial communities. In addition, when the total number of Operational Taxonomic Units (OTUs) was taken into consideration, a negative linear relationship with salinity was identified (see Chapter 2). Microbial community diversity patterns can also be differentiated based on the lagoon under study since each lagoon hosts a different sulfate-reducing microbial (SRM) community, again highly correlated with salinity. Moreover, the majority of environmental terms that characterized the SRM communities were classified to the marine biome, but terms belonging to the freshwater or brackish biomes were also found in stations were a freshwater effect was more evident (see Chapter 3). Taxonomic groups that were expected to be thriving in the sediments of the Benguela coastal upwelling system were absent or present but in very low abundances. Epsilonproteobacteria dominated the anaerobic assimilation of acetate as confirmed by their isotopic enrichment in the SIP experiments. Enhancement of known sulfate-reducers was not achieved under sulfate addition, possibly due to competition for electron donors among nitrate-reducers and sulfate-reducers, to the inability of certain sulfate-reducing bacteria to use acetate as electron donor or to the short duration of the incubations (see Chapter 4). Future research should focus more on the community functioning of such habitats; an increased understanding of the biogeochemical cycles that characterize these hypoxic ecosystems will perhaps allow for predictions regarding the intensity and direction of the cycling of elements, especially of nitrogen and sulfur given their biological importance. Regulation of hypoxic episodes will aid the end-users of these ecosystems to possibly achieve higher productivity, in terms of fish catches, which otherwise is largely compromised by the elevated hydrogen sulfide concentrations

Reappraisal of cellulase activities in mangrove wetlands resulting from preliminary investigations in East Java, Indonesia

本研究ではインドネシア東ジャワのパンパン湾周辺のマングローブ地域において，以前の研究 でセルラーゼ活性を有することが報告されていなかった軟体動物、節足動物、および腔腸動物に属する 無脊椎動物にセルラーゼ活性が広く分布することを明らかにした。さらに、セルラーゼ活性は、パン パン湾マングローブ干潟の落ち葉や堆積物、また湾内の海底堆積物にも検出され、バクテリアやメイ オベントスなどの関与が示唆された。また、これまで堆積物中の有機物はタンパク質やデンプンなど の易分解性とセルロースやリグニンなどの難分解性に区分されてきたが，セルロースはヘミセルロー スなどと共に生物分解を受けることから，食物連鎖の視点では準難分解性有機物として取り扱うこと が適切であると考えた.更に，湿地に生息する無脊椎動物が保持しているセルラーゼが食物連鎖で果 たす役割を理解するために、既報告の研究成果をレビューし，水生無脊椎動物のセルラーゼに関する 情報を更新した.Saline wetlands are empirically known to play an important role in the decomposition of terrestrial organic matter that is difficult to degrade, such as cellulose. The true nature of this role has been underestimated for a long time, because only microorganisms inhabiting saline wetland sediments, or those symbiotically living in aquatic invertebrates, were considered responsible until very recently. Although it is still unknown whether the majority of planktonic/benthic invertebrates possess endogenous cellulase, it is necessary to comprehensively investigate the distribution of cellulase activities in saline wetland invertebrates before any further studies. In the present study, we found that cellulase activities were widely distributed in invertebrates inhabiting a mangrove area of East Java, Indonesia, including Mollusca, Arthropoda and Cnidaria species that were not reported to have cellulase activity in previous studies. Moreover, cellulase activities were also detected in fallen leaves and sediments along the coastline, or below the water surface in Pang-Pang Bay of East Java, suggesting the involvement of small organisms such as meiobenthic invertebrates. To date, organic matter in sediments has been empirically classified into easy-to-decompose organic matter (EDOM) such as protein and starch, and non- degradable organic matter (NDOM) such as cellulose and lignin. However, from the viewpoint of food chain- related research, cellulose undergoes biodegradation together with hemicellulose. We thus propose to classify cellulose as quasi-hard-to-degrade organic matter (qHDOM). To understand the role played by invertebrates in the decomposition of qHDOM in wetlands, we therefore updated the information on aquatic invertebrates’ cellulase through a review of previous studies

Reviews and syntheses: Biological indicators of low-oxygen stress in marine water-breathing animals

Anthropogenic warming and nutrient over-enrichment of our oceans have resulted in significant, and often catastrophic, reductions in dissolved oxygen (deoxygenation). Stress on water-breathing animals from this deoxygenation has been shown to occur at all levels of biological organization: cellular, organ, individual, species, population, community, and ecosystem. Most climate forecasts predict increases in ocean deoxygenation; thus, it is essential to develop reliable biological indicators of low-oxygen stress that can be used by regional and global oxygen monitoring efforts to detect and assess the impacts of deoxygenation on ocean life. This review focuses on responses to low-oxygen stress that are manifest at different levels of biological organization and at a variety of spatial and temporal scales. We compare particular attributes of these biological indicators to the dissolved oxygen threshold of response, timescales of response, sensitive life stages and taxa, and the ability to scale the response to oxygen stress across levels of organization. Where there is available evidence, we discuss the interactions of other biological and abiotic stressors on the biological indicators of low-oxygen stress. We address the utility, confounding effects, and implementation of the biological indicators of oxygen stress for research and societal applications. Our hope is that further refinement and dissemination of these oxygen stress indicators will provide more direct support for environmental managers, fisheries and mariculture scientists, conservation professionals, and policymakers to confront the challenges of ocean deoxygenation. An improved understanding of the sensitivity of different ocean species, communities, and ecosystems to low-oxygen stress will empower efforts to design monitoring programs, assess ecosystem health, develop management guidelines, track conditions, and detect low-oxygen events.</p