Coastal Bay Research Articles

A new species of testate amoeba, <i>Arcella prismatica</i> sp. nov. (Amoebozoa: Arcellinida), from peatlands in Ontario and Quebec, Canada

Arcella is a genus of testate amoebae with a radially symmetrical shell composed of secreted material arranged in hexagonal units. Within the genus, species are distinguished by the morphology and dimensions of the shell. We describe a new species, Arcella prismatica sp. nov., discovered in a brown-water lake in the Mer Bleue Bog Conservation Area, a protected wetland in the city of Ottawa, Ontario, Canada. Specimens of the same morphotype have also been found in a subarctic peatland on the James Bay coast, near the village of Chisasibi, Quebec, Canada. The species has a polyhedral shell with a relatively flat dorsal surface and an irregularly crenulated aperture, a combination of characters not found in other members of the genus. The discovery of a novel and evidently widely distributed Arcella within the limits of a populous North American city is a reminder that the diversity of microbial eukaryotes is still poorly understood. Further exploration of undersampled peatland habitats can be expected to reveal new organisms and new relationships among known species.

Spatiotemporal dynamics and influencing factors of native and invasive saltmarshes in a rapidly silting bay during 1985–2023

Globally, native saltmarshes are declining, while invasive saltmarshes are expanding rapidly. However, the underlying processes and driving mechanisms behind these trends remain poorly understood, particularly in rapidly silting coastal bays. Here, we investigated the spatiotemporal dynamics and influencing factors of native saltmarshes (Scirpus mariqueter and Phragmites australis) and invasive Spartina alterniflora in Yueqing Bay, eastern China, by interpreting Landsat series images during 1985-2023. Results showed that native saltmarshes significantly decreased from 632.24 ha to complete disappearance, while S. alterniflora expanded from zero to 2872.90 ha in Yueqing Bay during 1985-2023. Specifically, S. mariqueter experienced a notable decline from 1985 to 1995, subsequent growth between 2000 and 2005, and another reduction from 2005 to 2010. P. australis expanded from 2005 to 2010 but shrank from 2010 to 2015 as S. alterniflora encroached upon its habitats. By contrast, S. alterniflora consistently expanded annually, except when it was eradicated by human interference. Both natural factors and human activities influenced native and invasive saltmarshes; for instance, mudflat reclamation facilitated saltmarsh expansion by creating suitable habitats during a certain period, particularly for S. alterniflora. From 1984 to 2018, the coastline extended seaward, causing sedimentation and landward transformation, which contributed to the expansion of S. alterniflora. However, the 118.05 ha mangrove forests negatively impacted S. alterniflora, as planting mangroves often involves the removal of existing S. alterniflora. Additionally, maximum tidal range and mean annual temperature positively affected saltmarshes. Our study highlighted the influence of natural factors and human activities on the spatiotemporal dynamics of both native and invasive saltmarshes in rapidly silting bays, underscoring the urgent need for conservation, restoration, and management of native saltmarshes.

Intensification of sediment flux by wind-induced residual currents in a heavily contaminated, micro-tidal bay.

Wind-induced currents are the major forces responsible for sediment resuspension and transport in micro-tidal bays. To reveal the impact of wind-induced residual currents on the sediment flux, in-situ measurements using acoustic Doppler current profilers (ADCPs) were conducted at two mooring stations in a heavily contaminated, micro-tidal Onsan Bay. During the mooring period, the suspended sediments at both stations were transported seaward (landward) at the surface (bottom) layer mainly through the residual currents (mean-flow flux Fmean: > 70% of the total flux). Under northerly winds, the landward bottom residual currents at both stations strengthened, resulting in the "intensification" of landward Fmean. This suggests that the northerly winds might be a primary factor intensifying the landward sediment fluxes, potentially resulting in the increased sediment deposition into the bay. The findings provide insights into managing sedimentation in contaminated coastal bays and highlight the importance of wind effects on sediment transport in micro-tidal bays.

Microbial community assembly and co-occurrence patterns in Sanmen bay: A comparative analysis before and after nuclear power plant operation.

The limited availability of historical data has resulted in the ongoing debate regarding the short-term effects of thermal discharge from nuclear power plants (NPPs) on microbial communities, including both prokaryotes and microeukaryotes. This study focused on the co-occurrence patterns, assembly processes, and community functions in the eutrophic coastal waters of Sanmen Bay (SMB) before and after NPP operation. Gammaproteobacteria and Alphaproteobacteria were the dominant prokaryotic taxa, while Dinoflagellates consistently maintained their prevalence in SMB. This suggests that short-term thermal discharge does not significantly alter the composition of microbial communities. The co-occurrence networks were primarily composed of Gammaproteobacteria, Alphaproteobacteria, Dinoflagellates, Diatoms, and Cryptophyta, with similar network topological properties across sampling groups. Homogeneous selection and dispersal limitation were the main mechanisms that controlled the assembly of microbial communities. Homogeneous selection was more significant for prokaryotes, while dispersal limitation was the dominant factor in microeukaryotes, irrespective of a thermal discharge. Prokaryotic β-diversity and nutrients showed substantially positive effects on the functional potential of the prokaryotic community. The findings indicate that short-term thermal discharge from the NPP, as long as they do not cause a significant overall temperature increase in the bay, are unlikely to impact the microbial communities within the coastal bay ecosystem.

Comparing surface currents near the mouth of three bays along the U.S. East Coast: Chesapeake Bay, Delaware Bay, and New York Bay

Monthly surface currents at 2 km resolution near the mouths of three U.S. east coast bays were obtained from high-frequency radars (Coastal Ocean Dynamics Application Radar, CODAR) during 2012–2024. The currents near these bays, the Chesapeake Bay (CB), the Delaware Bay (DB) and the New York Bay (NB) were analyzed to infer similarity and differences, as well as potential common forcing from regional and basin-scale factors. The contribution to flow variability from local and remote forcing is evaluated by comparing surface currents with (a) river discharges into each bay, (b) with local and regional winds, and (c) with the North Atlantic Oscillation (NAO). The results show that surface flow variability near the mouth of the bays is linked with all three driving factors. The three bays often show similar flow patterns not only of the seasonal cycle, but also during extreme weather events. For example, increased surface flow into the bays from the Atlantic Ocean is seen when hurricanes are observed offshore in the fall, and increased surface flow from the bays is seen during winter storms. During positive NAO phases, eastward flow from all three bays increased due to intensified westerly winds, while during negative NAO phases flow decreased with weakening winds in the region. River discharges into the bays increased during 2012–2019 but decreased during 2019–2024. This change in river discharge trend was especially large in the CB, resulting in a change in trends of the surface currents. Monthly currents of each bay are only weakly correlated with the monthly river flow (R ~ 0.2–0.3; P < 0.05), while the seasonal cycles of rivers and currents have higher correlations (R ~ 0.6–0.7). Local winds show high correlations with the monthly currents (R ~ 0.75) with the current direction ~ 45° to the right of the wind, as expected from Ekman theory. However, contributions to current variability from regional and remote factors cannot be ignored. The results demonstrate the complex nature of the currents near the mouth of bays since multiple drivers, including estuarine, coastal and open ocean dynamics contribute to the observed variability.

Assessment of Heavy Metals and Total Petroleum Hydrocarbons in Bottom Sediments of Kuwait Bay

Contaminated marine environments can be explicitly studied using chemical compounds and concentration of pollutants suspended in bottom sediment. Sediments act as repositories for pollutants, and have significant implications as they may pose a potential risk to the environment. In this paper, the geochemistry and provenance of bottom sediments from 17 stations, located along the Kuwait Bay, were studied during June and July 2024. The sediment samples were collected from each station using VanVeen grab sampler and were analysed for physical and chemical parameters for inorganic nutrients, BOD, COD, TOC, TPH and related heavy metals to delineate the extent of pollution levels and their distribution in the Bay. The main sources of pollution along the coast of Kuwait Bay are storm water outlets, emergency sewage discharges, ports, navigation channels, and desalination power plants. Results revealed elevated levels of inorganic nutrients (SiO&amp;lt;sub&amp;gt;2 &amp;lt;/sub&amp;gt;(3.75 mg/l), NH&amp;lt;sub&amp;gt;3 &amp;lt;/sub&amp;gt;(2.35 mg/l), NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; (1.21 mg/l), NO&amp;lt;sub&amp;gt;2 &amp;lt;/sub&amp;gt;(1.22 mg/l) and PO&amp;lt;sub&amp;gt;4 &amp;lt;/sub&amp;gt;(3.25 mg/l)) and TPH (601 mg/kg) in all the investigated sites within the bay. Elevated levels of metals Ni, V and Cr were discovered mostly at station 15 in front of Gazalle outlet and station 17 near the Power station outlet. The metal concentration of Ni (103.4 mg/kg) and V (44.153 mg/kg) exceeded the geo-chemical background levels established for sediment quality guidelines as compared to Cr, Cu and Cd which were found in varying levels (83.5 mg/kg, 40.7 mg/kg and 2.9 mg/kg, respectively), but below the probable effect levels (PEL). While Zn, Fe, Mn were within acceptable limits and Ag, As, Hg, and Pb were found to be very low. The contamination levels are mostly related to the characteristics and homogeneity of the clay presence in the bottom sediments which is highly biogenous. The overall objectives of this study is to determine the distribution, degree of contamination and sources in bottom sediments of Kuwait Bay. The novelty of this study lies in its ability to link pollutant levels to specific anthropogenic activities, offering critical insights into the bay’s environmental health. The findings of this study are essential for formulating targeted mitigation strategies to protect Kuwait Bay’s marine ecosystem from further degradation.

Density and diversity of larval fish in some coastal bays in Sharm El-Sheikh, northern Red Sea, Egypt

This study was carried out to investigate the composition and the spatial and temporal distribution of coral reef fish larvae in Port Bay, Sharm El- Maya Bay and Naama bay located in Sharm El-Sheikh area on the Egyptian Red Sea coast. Ichthyoplankton samples were collected monthly for one year mostly in the morning just before and at sunrise. A net of 100 cm, and 0.5 mm mesh size was towed horizontally parallel to the reef for 5–10 min. Throughout the period of study, a total of 205 plankton samples resulted in a collection of 3678 larvae representing 46 taxa and 32 fish families. Although larvae occurred all the year round, the general pattern showed two peaks in summer and winter with their maximum density in August with 1030 individuals/1000 m3. The lowest density of fish larvae was observed in September with 12 individuals/1000 m3. Regarding the distribution in bays, Port Bay (PRT) recorded the highest larval density where 1476 individuals/1000 m3 were collected. On the other hand, the lowest density was recorded in Sharm El-Maya Bay (SMB) with an average density of 908 larvae/1000 m3. The highest density of fish larvae occurred in any sample was recorded in Naama bay in August with a density of 1824 individuals/1000 m3. In several cases the spawning seasons of these taxa as determined from the present work based on the seasonal occurrence of larvae coincides mostly with that obtained from the literature based on the reproductive biological studies. Results obtained during this work reflected the importance of fish eggs and larvae survey in the management and conservation of reef fish in the Red Sea.

The efficacy of wastewater treatment plant on removal of perfluoroalkyl substances and their impacts on the coastal environment of False Bay, South Africa

Per- and polyfluoroalkyl substances (PFASs), which have their origins in both industrial processes and consumer products, can be detected at all treatment stages in wastewater treatment plants (WWTPs). Quantifying the emissions of PFAS from WWTPs into the marine environment is crucial because of their potential impacts on receiving aquatic ecosystems. In this study, the levels of five PFAS were measured in both influent and effluent sewage water samples obtained from a municipal WWTP, the discharges of which flow into False Bay, on the Indian Ocean coast of Cape Town, South Africa. Additionally, seawater, sediment, and biota samples from eight sites along the False Bay coast were also analysed. Results showed high prevalence of PFAS in the different environmental matrices. Perfluorononanoic acid was most dominant in all these matrices with maximum concentration in wastewater, 10.50 ng/L; seawater, 18.76 ng/L; marine sediment, 239.65 ng/g dry weight (dw); invertebrates, 0.72–2.45 µg/g dw; seaweed, 0.36–2.01 µg/g dw. The study used the chemical fingerprint of five PFASs detected in WWTP effluents to track their dispersion across a large, previously pristine marine environment and examined how each chemical accumulated in different marine organisms. The study also demonstrates that primary and secondary wastewater treatment processes cannot fully remove such compounds. There is thus a need to improve effluent quality before its release into the environment and promote continuous monitoring focusing on the sources of PFAS, including their potential transformation products, their environmental fate and ecological risks, particularly in areas receiving effluents from WWTP.

Temporal and spatial dynamics of the non-indigenous bryozoan, Amathia verticillata, and its associated invertebrate community

The widespread non-indigenous bryozoan, Amathia verticillata primarily colonizes in coastal bays and harbors on anthropogenic structures. Although this habitat-forming bryozoan is widely recognized to house a variety of marine invertebrates within its structure, little is known about their spatiotemporal dynamics and their associated invertebrate community in Southern California, USA. Thus, we undertook a comprehensive yearlong study (July 2021–2022) in an urbanized estuary (Mission Bay, San Diego) to quantify A. verticillata percent cover and abiotic conditions at 6 stations with varying environmental conditions. The seasonal and spatial gradients in temperature and salinity within Mission Bay were as expected with seasonal hypersalinity typical of Mediterranean climate regions. The percent cover of A. verticillata was positively correlated with temperature with the highest percent cover found during the warmest periods, and higher average percent cover found in the warmer, eastern parts of Mission Bay. We also collected three replicate A. verticillata colonies to characterize the marine invertebrate community associated with this non-indigenous bryozoan. We identified 25 families, 24 genera, and 19 organisms to species belonging to the taxonomic groups: amphipods, isopods, tanaids, and polychaetes. Furthermore, we identified juvenile stages and ovigerous females living within A. verticillata. None of the identified invertebrate families contributed more than 21 % to the community. The seasonal growth and annual temporal patterns of A. verticillata may prevent competitively dominant species from becoming established within the invertebrate community and allow A. verticillata to harbor a diverse invertebrate community. Sphaeromatidae isopods were the most common family found in the bryozoan colonies, likely reflecting their broad environmental tolerances. Additionally, while some of the invertebrates found within A. verticillata were also non-indigenous species, more work needs to be done to determine if A. verticillata disproportionately supports these species over native species. Collectively, our results imply that A. verticillata functions as a nursery habitat on anthropogenic structures for peracarid crustaceans and polychaetes. Furthermore, A. verticillata assemble analogous communities across their distribution, which may indicate that invasions are homogenizing biota globally.

Evaluation of Suitability Based on Integrated Land-Sea Spatial Planning: A Case Study of Yazhou Bay Coast Zone in Sanya, China

Evaluation of Suitability Based on Integrated Land-Sea Spatial Planning: A Case Study of Yazhou Bay Coast Zone in Sanya, China

Citizen science enhances understanding of sea turtle distribution in the Gulf of California.

Citizen science is a valuable tool for addressing spatial distribution gaps in endangered species, especially in data-limited regions. Given the logistical and financial challenges of studying migratory species, this cost-effective approach contributes to strategic conservation planning. The Bay of La Paz, located in Baja California Sur, México, is considered an ecologically important region within the larger Gulf of California. Due to its rich biodiversity and abundant natural resources, the region serves as a hub for ecotourism and fishing, affording diverse opportunities for community-based scientific initiatives. This paper examines the value of citizen science contributions from three diverse community groups (i.e., coastal residents, SCUBA divers, and artisanal fishers) to help scientists obtain information on sea turtle distribution in the Bay of La Paz. Our findings represent the first records of loggerhead turtles (Caretta caretta) in the bay based on ten citizen science reports that include live and dead turtles (either observed swimming, as bycatch, or stranded), providing new information on an endangered pelagic species identified in a coastal bay. Although the sample size is small, our diversity of sources and sighting types highlight the value of collaborative citizen science initiatives in complementing traditional research methods.

Drivers of Seasonal and Diel Methane Emissions From a Seagrass Ecosystem

AbstractSeagrass meadows are effective sinks of atmospheric carbon dioxide (CO2). However, there is little insight on how methane (CH4) emissions may potentially offset carbon sequestration in seagrass meadows. Here, we resolve diel and seasonal dynamics of CH4 and CO2 water‐air fluxes over a cold‐temperate Zostera marina seagrass meadow using high‐resolution timeseries observations in seawater. CH4 was emitted from the seagrass‐dominated coastal bay year‐round to atmosphere with CH4 fluxes ranging from 0.2 to 2.6 μmol m−2 d−1. These fluxes are at the lower end of earlier estimates based mostly on short‐term (i.e., 1 day) observations. The 13‐fold seasonal fluctuations in CH4 emissions were greater than the 6‐fold diel fluctuation. Radon observations imply that dissolved CH4 was primarily originated from sediment porewater. The main fate of CH4 in the water was outgassing to the atmosphere via wind forcing. Oxygen and temperature partially controlled dissolved CH4 seasonal dynamics. There was an annual average uptake of CO2 from the atmosphere (−0.9 ± 1.5 mmol m−2 d−1) driven by enhanced photosynthesis in the spring and summer. The CO2‐equivalent CH4 outgassing (0.5 ± 0.6 g CO2 eq m−2 yr−1) offsets only 0.8% of the sediment carbon accumulation in this cold‐temperate Z. marina meadows over a 20‐year time horizon. The CO2‐equivalent CH4 flux was 6% of the average annual CO2 uptake. Hence, CH4 emissions from this cold‐temperate seagrass meadow acted as a minor offset to carbon sequestration.

Habitat characteristics of Asian moon scallops (Amusium pleuronectes) in Makassar Strait and Bone Bay Waters, Indonesia

Abstract. Budiyati, Omar SBA, Nartiningsih A, Widowati I, Kasim N, Yusuf M, Riana AD. 2024. Habitat characteristics of Asian moon scallops (Amusium pleuronectes) in Makassar Strait and Bone Bay Waters, Indonesia. Biodiversitas 25: 3423-3430. Scallops (Amusium pleuronectes Linnaeus 1758), also known as axe clam, is a type of bivalve mollusk from the family Pectinidae that lives in marine or generally in coastal areas and can be found in all marine waters, including tropical regions such as Indonesia. Scallops are of economic value as a food source because scallops contain a lot of protein and are low in fat. In South Sulawesi, Indonesia, scallops are found in almost all coastal areas, both on the coast of the Makassar Strait and on the coast of Bone Bay and Flores Sea waters. The present study aims to illustrate and compare the habitat characteristics of the Asian moon scallops (A. pleuronectes) from Makassar Strait and Bone Bay. The research method used is quantitative descriptive, with the type of research conducted being a comparative study. The method and type of research used are based on the purpose of the study, which is to compare the habitat characteristics of scallops that live in the waters of the Makassar Strait, which is in the western side of South Sulawesi (Sulawesi Island), and Bone Bay which is in the eastern side of South Sulawesi (Sulawesi Island). The study was conducted from January to October 2022 in two water areas, Makassar Strait in Makassar City and Bone Bay in Bone District. The data consisted of primary data obtained in the research fields by measuring physical parameters, including temperature, salinity, water depth, DO, and pH. The study results show that the temperature in the two sites was around 28.0-30.5oC, salinity around 28.0-39.0 ppt, the water's depth around 9-20 m, DO about 5.0-6.0 ppm, and pH around 5.60-8.75. In conclusion, the habitat of the Asian moon scallops in Makassar Strait dan Bone Bay has relatively similar characteristics.

Adsorption of Pb, Ni and Zn by coastal soils: Isothermal models and kinetics analysis

Coastal areas are facing increasing heavy metal pollution as a result of various anthropogenic activities, posing a serious threat to ecosystems. Modeling and understanding the sorption behavior of heavy metals in soils are essential for assessing their mobility and risk in the coastal landscapes. The aim of this study was to examine the adsorption behavior of Pb²⁺, Ni²⁺, and Zn²⁺ by common soil types of the Lower Don and the Taganrog Bay coast in Russia to better understand their potential environmental implications. The soil capacities for heavy metal adsorption and retention were determined using isothermal models. The maximum adsorption capacity and the binding strength parameter for the heavy metals were calculated, revealing significant differences among the soils. Haplic Chernozem emerged with superior values, while Gleyic Solonchak Sulfidic and Umbric Fluvisol trailed the lowest. All soils exhibited a greater adsorption capacity and binding strength for Pb compared to the other metals. The influence of soil characteristics on sorption and retention was also examined. The Pseudo-second-order model provided a more accurate description of the adsorption kinetics of heavy metals by the studied soils. The co-presence of metals in the system affected their sorption by the soils due to competition: soils adsorbed fewer metals but retained them more strongly. These findings are important for developing effective strategies to reduce heavy metal pollution in coastal ecosystems.

Implementation of the Empowerment Program for Culinary Tourism Business Actors in the Coastal Area of Manado Bay, North Sulawesi Province

The Manado City Government through the 2020-2025 regional tourism development master plan has determined a special tourism destination cluster for culinary tourism areas with urban-coastal tourism attractions. The determination of this cluster is in line with the culinary potential managed by the community such as bakat sea fish and local snacks around the coast of Manado Bay. By using a qualitative research design, data was collected directly at the research location through interviews and observations, and secondary data was also collected electronically through internet media such as Google Scholar, WoS databases, Scopus, Arxiv by Cornell, Ulrich's Web, Science Direct, Directory of Open Access, JSTOR, SciELO, ERIC, ResearchGate and others. Data analysis using an interactive analysis model with data reduction, data display and conclusion drawing/verification stages. In addition, for the validity of the data analysis discussion, a focus group discussion was also conducted. The research findings that the implementation of the empowerment program for culinary tourism entrepreneurs in the Manado Bay Coastal Area has been carried out by the Manado City Government. Training, mentoring, provision of capital and business facilities and supervision as a form of empowerment activities carried out. The empowerment program is carried out separately or in collaboration with other public organizations. The seriousness in managing and developing businesses from the Community is a measure of the success of the implementation of the empowerment program.

Classification of vegetation of the Barents Sea coast at the mouth of the Indiga River

Classification of coastal vegetation from the standpoint of the ecological-phytocoenotic approach at the estuary of the Indiga River, flowing into the southeastern part of the Barents Sea, is presented. On the base of 131 relevés of coastal vegetation, 23 associations in 18 formations were identified. The coastal vegetation in different biotopes differs in the structure and features of the phytocoenoses floristic composition. Based on the signs of vegetation cover, mesorelief, and hydrological features of the shores, the following biotopes were identified: saline and brackish marshes, beaches and dunes, tidal flats at the mouths of estuaries, saline and brackish lagoon lakes on marshes. The marches with 14 described associations have the highest phytocoenotic diversity. A phytocoenotic diversity of the beaches is noticeably less, 4 associations are described there. The vegetation background of the beaches is formed by the communities of the Leymeta arenarii formation, the vegetation background of the salty marshes is formed by the communities of the Cariceta subspathaceae, Cariceta glareosae, and Cariceta mackenziei formations. In saline lakes, large areas are occupied by communities of the Hippurideta tetraphyllae formation, and the communities of the Triglochineta maritimi and Plantagineta subpolaris formations are rare, the northern limit of their range runs approximately along the Indiga mouth. The vegetation of brackish marshes is mainly formed by the Cariceta salinae herbosum, Junceta gerardii, and Cariceta rariflorae communities. At the mouth of Indiga estuary, large areas are occupied by communities of the Magnocariceta formation. In the mouth of the Indiga, a little north of the range limit, communities of Eleocharis uniglumis, a rare species in the Nenets Autonomous Okrug, are described for the first time at the rank of association Eleocharitetum uniglumis. The aquatic vegetation of desalinated lagoon lakes is represented by the Myriophylleta sibirici formation. The halophyte vegetation of the Indiga River estuary is compared with the estuaries of the rivers of the Kanin Peninsula and the Pechora Bay. The ordination of geobotanical relevés shows a greater similarity of the coastal vegetation of the Indiga estuary with the estuaries of the rivers flowing on the Kanin Peninsula of the White and Barents Seas basins and with the vegetation of the rivers estuaries of the Pechora Bay coast. The article has an electronic appendix (https://journals.rcsi.science/0006-8136/issue/archive).

Fishery status of the green tiger shrimp (Penaeus semisulcatus) in Palk Bay, in the southeast coast of India: Local and global perspectives

The green tiger shrimp (Penaeus semisulcatus De Haan, 1844), traded as Mandapam flower shrimp internationally, is large-sized shrimp and landed on the coast of Palk Bay, India. This work aimed to describe the status of its fishery and identify challenges for the better management of these resources. The estimated fishery landings of P. semisulcatus in 2022 were 7658 t, with an annual average of 6493 t from 2020 to 2022, contributing to the total penaeid shrimp landings in Palk Bay at 57.6%. The economic value of this fishery was estimated to be around $53 million USDs annually (1 USD = 83.16 INR). Between 2007 and 2022, there was a significant difference between green tiger shrimp and total penaeid shrimp landings in Palk Bay across gears and years. All shrimp from Palk Bay have export markets to Japan, the USA, China, and European countries. The average annual export of P. semisulcatus (2015-16 to 2022–23) was 3532 t ($30.9 million USDs). In 2022–23, the USA was the biggest importer of frozen shrimp, followed by China, the European countries, Southeast Asia, Japan, and the Middle-East countries. We formulated a policy guidelines framework for the management and co-management of the green tiger shrimp fishery in Palk Bay based on a precautionary approach.

Technical Study of the Concept of Permanent Housing Relocation around the Palu Koro Fault after the 28 September 2018 Disaster

The earthquake that struck Central Sulawesi on September 28, 2018, had a significant impact on Palu City, Donggala Regency, and Sigi Regency. The impact included a tsunami along the coast of Palu Bay and liquefaction in several areas, leading to extensive damage to infrastructure. As part of the post-disaster recovery efforts, permanent shelters (HUNTAP) are being constructed for the survivors. The purpose of this research is to perform a technical assessment of residential relocation based on risk factors that could lead to future disasters. The method involves descriptive analysis, including the following stages: (1) Reviewing literature from various journals, regulations, technical provisions, and related databases, and (2) identifying variables and criteria that could lead to disasters in areas designated for permanent residential relocation. The research results reveal several influential variables, as follows: (1) Potential for flooding, including: (a) high rainfall, (b) susceptibility to air infiltration, (c) risk of flash floods, (d) erosion of river basins, (e) sedimentation, (f) availability of adequate drainage system facilities; (2) risk of landslides is significantly influenced by: (a) shear angle, (b) pore water pressure, (c) slope gradient; (3) liquefaction indicators include (a) Groundwater level less than 10 meters, (b) sandy soil thickness less than 12 meters underground, (c) increased surface earthquake activity, (d) soil density; (4) tsunami risk is associated with several influential variables: (a) Shallow epicenter with a depth of less than 33 km (b) angle and type of fault, with thrust or thrust faults being the most dominant, (c) distance from the epicenter and location in the middle of the sea, (d) characteristics such as beach shape, open beach morphology, low surface slope, and seabed depth; (5) high current voltage is indicated by the distance and type of voltage capacity; and (6) airplane trajectories are influenced by runway distance and flight path.

Drought reduces nitrogen supply and N2O emission in coastal bays

Severe droughts are increasingly prevalent under global climate change, disrupting watershed hydrology and coastal nitrogen cycling. However, the specific effects of drought on nitrogen transport from land to sea and subsequent nitrogen dynamics remain inadequately understood. In this study, we evaluated the consequences of the 2020–2022 drought on nitrogen supply and N2O emissions in Xiamen Bay, Southeast China. The results showed that drought significantly reduced annual NH4N, NO2N, and NO3N concentrations in Xiamen Bay by 49.4 %, 32.1 %, and 40.3 %, respectively, compared with the pre-drought year of 2019. The decline in NH4N concentration was mainly attributed to reduced surface runoff across all seasons. NO3N and NO2N concentrations declined only during spring and summer, primarily due to increased potential evapotranspiration (PET) hindering nitrogen supply via groundwater and concurrently enhancing land denitrification. Annual N2O emission from Xiamen Bay decreased by 40.0∼72.7 % during the drought, highly correlated with the decline in the concentrations of NO3N, DIN, and DTN (p < 0.001). Comparative analysis revealed that NO3N concentration exhibited consistent negative linear regressions with PET and declined as evaporative demand drought conditions worsened across Xiamen Bay, Sansha Bay, and Chesapeake Bay throughout 2010–2022. NH4N concentration showed a positive regression with river discharge in Xiamen Bay, but negative regressions in the other two bays. Our results indicates that drought reduces N2O emission primarily driven by nitrate substrate reduction in the bay. This study provides new insights for predicting coastal nitrogen dynamics and greenhouse gas emissions under global environmental change.

Датирование современной осадочной толщи краевых бассейнов Восточного Мурмана (Кольский полуостров) на примере губ Ярнышная и Зеленецкая

The authors have studied sediment genesis in the Kola Peninsula bays, the most popular and developed part of the coastal shelf by the population. The main tool used is the method of radioisotope chronology of sedimentary layers based on changes in the specific activity of the natural isotope 210Pb and technogenic 137Cs. It has been revealed that the marginal basins of Murman are characterized by monotonous sedimentation in recent centuries. The average sedimentation rate is 0.15—0.17 cm/year. The sedimentary sequence is composed of silty-pelite-sized material. It has been established that the role of ice rafting in the formation of bottom sediment in coastal bays has decreased over the past centuries.