Blue carbon sink capacity of mangroves determined by leaves and their associated microbiome.

Mangroves play a globally significant role in carbon capture and storage, known as blue carbon ecosystems. Yet, there are fundamental biogeochemical processes of mangrove blue carbon formation that are inadequately understood, such as the mechanisms by which mangrove afforestation regulates the microbial-driven transfer of carbon from leaf to below-ground blue carbon pool. In this study, we addressed this knowledge gap by investigating: (1) the mangrove leaf characteristics using state-of-the-art FT-ICR-MS; (2) the microbial biomass and their transformation patterns of assimilated plant-carbon; and (3) the degradation potentials of plant-derived carbon in soils of an introduced (Sonneratia apetala) and a native mangrove (Kandelia obovata). We found that biogeochemical cycling took entirely different pathways for S. apetala and K. obovata. Blue carbon accumulation and the proportion of plant-carbon for native mangroves were high, with microbes (dominated by K-strategists) allocating the assimilated-carbon to starch and sucrose metabolism. Conversely, microbes with S. apetala adopted an r-strategy and increased protein- and nucleotide-biosynthetic potentials. These divergent biogeochemical pathways were related to leaf characteristics, with S. apetala leaves characterized by lower molecular-weight, C:N ratio, and lignin content than K. obovata. Moreover, anaerobic-degradation potentials for lignin were high in old-aged soils, but the overall degradation potentials of plant carbon were age-independent, explaining that S. apetala age had no significant influences on the contribution of plant-carbon to blue carbon. We propose that for introduced mangroves, newly fallen leaves release nutrient-rich organic matter that favors growth of r-strategists, which rapidly consume carbon to fuel growth, increasing the proportion of microbial-carbon to blue carbon. In contrast, lignin-rich native mangrove leaves shape K-strategist-dominated microbial communities, which grow slowly and store assimilated-carbon in cells, ultimately promoting the contribution of plant-carbon to the remarkable accumulation of blue carbon. Our study provides new insights into the molecular mechanisms of microbial community responses during reforestation in mangrove ecosystems.

Differential capacity of phragmites ecotypes in remediation of inorganic contaminants in coastal ecosystems: Implications for climate change.

Remediating inorganic pollutants is an important part of protecting coastal ecosystems, which are especially at risk from the effects of climate change. Different Phragmites karka (Retz) Trin. ex Steud ecotypes were gathered from a variety of environments, and their abilities to remove inorganic contaminants from coastal wetlands were assessed. The goal is to learn how these ecotypes process innovation might help reduce the negative impacts of climate change on coastal environments. The Phragmites karka ecotype E1, found in a coastal environment in Ichkera that was impacted by residential wastewater, has higher biomass production and photosynthetic pigment content than the Phragmites karka ecotypes E2 (Kalsh) and E3 (Gatwala). Osmoprotectant accumulation was similar across ecotypes, suggesting that all were able to successfully adapt to polluted marine environments. The levels of both total soluble sugars and proteins were highest in E2. The amount of glycine betaine (GB) rose across the board, with the highest levels being found in the E3 ecotype. The study also demonstrated that differing coastal habitats significantly influenced the antioxidant activity of all ecotypes, with E1 displaying the lowest superoxide dismutase (SOD) activity, while E2 exhibited the lowest peroxidase (POD) and catalase (CAT) activities. Significant morphological changes were evident in E3, such as an expansion of the phloem, vascular bundle, and metaxylem cell areas. When compared to the E3 ecotype, the E1 and E2 ecotypes showed striking improvements across the board in leaf anatomy. Mechanistic links between architectural and physio-biochemical alterations are crucial to the ecological survival of different ecotypes of Phragmites karka in coastal environments affected by climate change. Their robustness and capacity to reduce pollution can help coastal ecosystems endure in the face of persistent climate change.

IMPACT OF CLIMATE CHANGE ON COASTAL ECOSYSTEM AND OUTDOOR ACTIVITIES: A COMPARATIVE ANALYSIS AMONG FOUR LARGEST COASTLINE COVERING COUNTRIES.

Climate change and coastal ecosystems have become challenging subjects for world sustainability. Humans, animals, and other ocean habitats are primarily affected by the harmful changes in climate. Coastal ecosystems support biodiversity and a wide range of species that serve as habitats for many commercially important fish species and enhance human activities in coastal areas. By engaging in coastal outdoor activities, individuals can experience numerous physical and mental health benefits, foster environmental awareness. This study provided valuable insights into the importance of coastal outdoor activities and their potential to improve our quality of life. This study undertook a challenging subject where we graphically and econometrically analyze the relationship and linkages among coastal indicators with other climate-concerning factors. The study comprises the ordinary regression and comparative analysis among the four largest coastline countries in the world. The study took a sample from Canada, Indonesia, Norway, and the Russian Federation from 1990 to 2022. The data is selected on a convenient basis. Results declared that each country has its unique challenges and opportunities in mitigating adverse climate change and retaining a sustainable coastal ecosystem. The study surprisingly revealed that climate change insignificantly affects the coastal ecosystem in Indonesia and the Russian Federation while it inversely affects the coastal ecosystem in Canada and Norway, showed that climate change on average declines coastal production by 0.0041922 and 0.0261104 in Canada and Norway respectively. The detailed review is given in the results section; however, the pooling analysis proved that at the aggregate level, a one percent increase in climate change caused a 0.02266-tonne decline in coastal ecosystems in the four largest coastline nations. There is a need for policies tend to increase CAP activities by implementing practical marine protected areas. Furthermore, scientific research and monitoring will be beneficial in restoring coastal sustainability.

Assessment of microplastics in coastal ecosystem of Bangladesh.

Microplastics (MPs) pose one of the major environmental threats to marine organisms and ecosystems on a global scale. The present study investigated MPs in surface water, beach sediments, and fish in two coastal areas of Bangladesh namely Cox's Bazar and Kuakata. The MPs were identified and characterized using three different techniques, including the binocular microscope, the ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy), and SEM-EDS (Scanning Electron Microscopy- Energy Dispersive Spectroscopy). The number of MPs in seawater was 10.1 ± 3.10 and 8.52 ± 3.92 items/100 L and in beach sediment, 13.2 ± 3.68 and 9.48 ± 3.63 items/100 g in Cox's Bazar and Kuakata, respectively. In fish samples, the abundance of MPs was 7.82 ± 1.28 and 6.82 ± 1.87 items/individual species of Cox's Bazar and Kuakata, respectively, where the highest quantities of MP were found in Euthynnus affinisand Sillago sihama and the lowest in Terapon jarbua and Pampus chinensisin Cox's Bazar and Kuakata, respectively. The number of MPs in GITs (Gastrointestinal tracts) was 1.63 ± 0.991 and 1.25 ± 0.546 items/g GIT and in BW (Body Weight) were 0.042 ± 0.014 and 0.037 ± 0.014 items/g BW in Cox's Bazar and Kuakata, respectively. There revealed a positive correlation between MP abundance and GIT weight and body weight in fish species. MPs were predominantly fiber-shaped, white/transparent, and small size. The most common MP polymers were polyethylene and polypropylene. SEM images of MPs demonstrate surface roughness, cracks, mechanical weathering and oxidative weathering, demonstrating their ongoing environmental exposure. The EDS spectrum unearthed that the MPs contained several elements (C, N, O, Na, Al, Fe, and Si). Findings from this study might be useful in coastal plastic particle management and to mitigate the potential risks associated with them.

Metatranscriptomics and metabarcoding reveal spatiotemporal shifts in fungal communities and their activities in Chinese coastal waters.

Fungal communities are diverse and abundant in coastal waters, yet, their ecological roles and adaptations remain largely unknown. To address these gaps, ITS2 metabarcoding and metatranscriptomic analyses were used to capture the whole suite of fungal diversity and their metabolic potential in water column and sediments in the Yellow Sea during August and October 2019. ITS2 metabarcoding described successfully the abundance of Dikarya during August and October at the different examined habitats, but strongly underrepresented or failed to identify other fungal taxa, including zoosporic and early-diverging lineages, that were abundant in the mycobiome as uncovered by metatranscriptomes. Metatranscriptomics also revealed enriched expression of genes annotated to zoosporic fungi (e.g., chytrids) mainly in the surface water column in October. This enriched expression was correlated with the two-fold increase in chlorophyll-a intensity attributed to phytoplanktonic species which are known to be parasitized by chytrids. The concurrent high expression of genes related to calcium signalling and GTPase activity suggested that these metabolic traits facilitate the parasitic lifestyle of chytrids. Similarly, elevated expression of phagosome genes annotated to Rozellomycota, an early-diverging fungal phylum not fully detected with ITS2 metabarcoding, suggested that this taxon utilizes a suite of feeding modes, including phagotrophy in this coastal setting. Our data highlight the necessity of using combined approaches to accurately describe the community structure of coastal mycobiome. We also provide in-depth insights into the fungal ecological roles in coastal waters, and report potential metabolic mechanisms utilized by fungi to cope with environmental stresses that occur during distinct seasonal months in coastal ecosystems.

Variability in seed salinity tolerance in an island coastal community.

BACKGROUND AND AIMS: Islands, with their long coastlines and increased vulnerability to sea level rise, offer compelling opportunities to investigate the salinity tolerance of coastal plants. Seeds are generally more vulnerable than other plant stages to increased stressors. The aim of this study was to characterize salinity tolerance during germination across a diverse pool of 21 species from 14 plant families found in coastal communities throughout the Hawaiian Islands in order to increase our general understanding of coastal plant ecology for conservation and restoration. METHODS: Seeds of each species were exposed to unfiltered/untreated seawater (35 ppt total salinity) and two salinity treatments (10 and 20 ppt) in which the seawater was diluted with distilled water, and germination percent and timing were compared to seeds in a distilled water control. Non-germinated seeds were then tested for recovery germination. We quantified and compared germination percent, time and recovery among species and across salinity levels and tested for heterogeneity related to seed size, dormancy class, habit and threatened status. KEY RESULTS: Although salinity tolerance varied considerably among species, salinity exposure generally reduced and delayed germination. The greatest effects were detected at higher salinity levels. Recovery germination overall was higher for seeds that had been exposed to higher salinity. None of the factors we explored emerged as predictors of salinity tolerance except seed mass, which tended to enhance germination at higher salinity. CONCLUSIONS: Species responses to salinity exposure indicate high vulnerability of coastal systems to increased salinity stress, and variability among species could lead to shifts in community assembly and composition under sea level rise. These results can help guide coastal ecosystem conservation and restoration management decisions in the face of climate change.

Dynamics of Benthic Nitrate Reduction Pathways and Associated Microbial Communities Responding to the Development of Seasonal Deoxygenation in a Coastal Mariculture Zone.

Intensive mariculture activities result in eutrophication and enhance coastal deoxygenation. Deoxygenation profoundly influences nitrate reduction processes and further the fate of nitrogen (N) in coastal systems. Herein, 15N isotope labeling, real-time PCR, and high-throughput sequencing techniques were jointly used to investigate the participation and seasonal dynamics of sediment nitrate reduction pathways and the succession of functional microbial communities during the development of seasonal deoxygenation in a coastal aquaculture zone. Denitrification dominated benthic nitrate reduction (46.26-80.91%). Both denitrification and dissimilatory nitrate reduction to ammonium were significantly enhanced by summer deoxygenation (dissolved oxygen levels fell to 2.94 ± 0.28 mg L-1), while anammox remained unchanged. The abundance of the nitrous oxide reductase gene nosZ increased during deoxygenation. The community of the nosZ gene was sensitive to deoxygenation, with Azospirillum and Ruegeria accounting for the majority. Pelobacter was overwhelming in the nrfA gene (encoding dissimilatory nitrite reductase) community, which was less affected by deoxygenation. The variations of benthic nitrate reduction processes were driven by bottom water oxygen combined with temperature, chlorophyll a, and microbial gene abundances and community compositions. Our results implicated that seasonal oxygen-deficient zones could be substantial N sinks of coastal ecosystems and important for N balance. Effective management measures need to be developed to avoid further exacerbation of coastal deoxygenation and maintain the sustainable development of mariculture.

Relationship among marine pollution, outdoor activities, and climate change: Fresh evidence from panel threshold regression analysis from coastal regions of China.

The mitigation of oceanic pollution is believed to be influenced by the expansion of marine economies and advancements in technology, as per existing research. Nevertheless, the current body of research on this topic is lacking in terms of exploring the potential nonlinearity of the relationship and fully understanding the extent to which the observed effects have been demonstrated. The present study endeavors to bridge the existing research void by investigating the coastal regions of China spanning the time from 2000 to 2020. The present study utilizes a panel threshold model to examine the non-linear effects of marine patents and per capita gross ocean product on marine pollution. The measure of marine pollution is based on the quantity of industrial wastewater that is discharged directly into the ocean. The research findings suggest that there is a notable association between the increase in per capita GOP and the worsening of marine pollution across the three stages of the panel threshold model. The impact of China's environmental issues appears to be decreasing over time, indicating that the country is currently in the early stages of the Environmental Kuznets Curve (EKC) before reaching its peak. Based on the analysis of current trends, it is possible to deduce that a potential negative correlation between the GOP and pollution could emerge if these patterns continue. The implication arises that the expansion of the marine economy has the potential to alleviate environmental stressors on the ocean. In the context of marine patents, the research findings did not reveal any significant correlations at the lower and intermediate stages. During the analysis of the high-level phase, it was observed that marine patents exerted a significant impact on pollution, indicating the growing importance of technological advancements in the marine industry for addressing and reducing marine pollution. The process of identifying the number of provinces and municipalities has been completed for all three phases. The development of the marine economy has garnered considerable attention due to its numerous policy implications.

Enhancing coastal ecosystem resilience: Investigating the interplay between safety criteria and ferry employee's perceptions to address climate change impacts.

Coastal ecosystems play an important part in mitigating the effects of climate change. Coastal ecosystems are becoming more susceptible to climate change impacts due to human activities and maritime accidents. The global shipping industry, especially in Southeast Asia, has witnessed numerous accidents, particularly involving passenger ferries, resulting in injuries and fatalities in recent years. In order to mitigate the impact of climate change on coastal ecosystems, this study aimed to evaluate the relationship between employees' perceptions of safety criteria and their own safety behaviour on Langkawi Island, Malaysia. A straightforward random sampling technique was employed to collect data from 112 ferry employees aboard Malaysian-registered passenger boats by administering questionnaires. The findings shed light on the strong connection between providing safety instructions for passengers and safety behaviour among ferry workers. Safety instructions should contain climate-related information to successfully address the effects of climate change. The instructions might include guidance on responding to extreme weather events and understanding the potential consequences of sea-level rise on coastal communities. The ferry company staff should also expand their safe behaviour concept to include training and preparation for climate-related incidents. The need to recognise the interconnectedness between climate change, ferry safety and the protection of coastal ecosystems is emphasised in this study. The findings can be utilised by policymakers, regulatory agencies and ferry operators to design holistic policies that improve safety behaviour, minimise maritime mishaps and preserve the long-term sustainability of coastal ecosystems in the face of difficulties posed by climate change.

Assessing coastal bathymetry and climate change impacts on coastal ecosystems using Landsat 8 and Sentinel-2 satellite imagery.

Coastal ecosystems are facing heightened risks due to human-induced climate change, including rising water levels and intensified storm events. Accurate bathymetry data is crucial for assessing the impacts of these threats. Traditional data collection methods can be cost-prohibitive. This study investigates the feasibility of using freely accessible Landsat and Sentinel satellite imagery to estimate bathymetry and its correlation with hydrographic chart soundings in Port Klang, Malaysia. Through analysis of the blue and green spectral bands from the Landsat 8 and Sentinel 2 datasets, a bathymetry map of Port Klang's seabed is generated. The precision of this derived bathymetry is evaluated using statistical metrics like Root Mean Square Error (RMSE) and the coefficient of determination. The results reveal a strong statistical connection (R2 = 0.9411) and correlation (R2 = 0.7958) between bathymetry data derived from hydrographic chart soundings and satellite imagery. This research not only advances our understanding of employing Landsat imagery for bathymetry assessment but also underscores the significance of such assessments in the context of climate change's impact on coastal ecosystems. The primary goal of this research is to contribute to the comprehension of Landsat imagery's utility in bathymetry evaluation, with the potential to enhance safety protocols in seaport terminals and provide valuable insights for decision-making concerning the management of coastal ecosystems amidst climate-related challenges. The findings of this research have practical implications for a wide range of stakeholders involved in coastal management, environmental protection, climate adaptation and disaster preparedness.

The dynamics of red Noctiluca scintillans in the coastal aquaculture areas of Southeast China.

Noctiluca scintillans (NS) adds an aesthetic appeal to many coastal areas because of their bioluminescence. An intense bloom of the red NS frequently occurs in the coastal aquaculture region of Pingtan Island in Southeastern China. However, when NS exceeds in abundance, it causes hypoxia which has devastating impacts on the aquaculture. This study was conducted in the Southeastern part of China with an aim to examine the relationship between the profusion of NS and its impacts on marine environment. Samples from four stations on Pingtan Island were collected for 12 months (January to December 2018) and were later analyzed in laboratory against five parameters, namely temperature, salinity, wind speed, dissolved oxygen, and chlorophyll a. Results showed that the NS blooms were particularly active during the months of May and June in the Pingtan Island area. The seawater temperatures during that time were recorded between 20 and 28.8 °C indicating the optimum survival temperature for NS. The NS bloom activity ceased above 28.8 °C. A principal component analysis (PCA) indicated that the richness of NS was positively associated with temperature and salinity, whereas there was a significant reverse correlation between NS accumulation and wind speed. NS is a heterotrophic dinoflagellate and relies on the predation of algae for reproduction; therefore, a significant correlation was observed between NS abundance and chlorophyll a concentration, and an inverse correlation was observed between NS and phytoplankton abundance. Additionally, red NS growth was observed immediately following the diatom bloom, suggesting that phytoplankton, temperature, and salinity are the essential factors in the evolution, progression, and termination of NS growth.

Multidrug-resistant epi-endophytic bacterial community in Posidonia oceanica of Mahdia coast as biomonitoring factor for antibiotic contamination.

Faced with the significant disturbances, mainly of anthropogenic origin, which affect the Mediterranean coastal ecosystem, Posidonia oceanica (L.) Delile has often been used to assess the state of health of this environment. The present study aims to determine the multidrug resistance patterns among isolated and identified epi-endophytic bacterial strains in P. oceanica seagrass collected from Mahdia coastal seawater (Tunisia). To investigate the bacterial community structure and diversity from coastal seawater samples from Mahdia, total DNA extraction and 16S rRNA gene amplification were performed and analyzed by denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed that some bands were specific to a given site, while other bands were found to be common to more than one sample. In the other hand, bacterial strains were isolated from 1 mL of leaves and epiphytes suspension of P. oceanica seagrass in marine agar. Forty-three isolates were obtained, seven of them were selected and identified on the basis of 16S rRNA gene sequence analysis. These isolates belonged to the genus Bacillus, exhibiting 98-100% of identity with known sequences. Susceptibility patterns of these strains were studied toward commonly used antibiotics in Tunisia. All identified isolates were resistant to Aztreonam (72.1%), Ceftazidime (60.5%), Amoxicillin (56%) and Rifampicin (51.2%). S5-L13 strain had presented the highest multidrug resistance with a MAR index of 0.67.

Habitat-specific responses of soil organic matter decomposition to Spartina alterniflora invasion along China's coast.

Plant invasions cause a fundamental change in soil organic matter (SOM) turnover. Disentangling the biogeographic patterns and key drivers of SOM decomposition and its temperature sensitivity (Q10 ) under plant invasion is a prerequisite for making projections of global carbon feedback. We collected soil samples along China's coast across saltmarshes to mangrove ecosystems invaded by the smooth cordgrass (Spartina alterniflora Loisel.). Microcosm experiments were carried out to determine the patterns of SOM decomposition and its thermal response. Soil microbial biomass and communities were also characterized accordingly. SOM decomposition constant dramatically decreased along the mean annual temperature gradient, whereas the cordgrass invasion retarded this change (significantly reduced slope, p < 0.05). The response of Q10 to invasion and the soil microbial quotient peaked at midlatitude saltmarshes, which can be explained by microbial metabolism strategies. Climatic variables showed strong negative controls on the Q10 , whereas dissolved carbon fraction exerted a positive influence on its spatial variance. Higher microbial diversity appeared to weaken the temperature-related response of SOM decomposition, with apparent benefits for carbon sequestration. Inconsistent responses to invasion were exhibited among habitat types, with SOM accumulation in saltmarshes but carbon loss in mangroves, which were explained, at least in part, by the SOM decomposition patterns under invasion. This study elucidates the geographic pattern of SOM decomposition and its temperature sensitivity in coastal ecosystems and underlines the importance of interactions between climate, soil, and microbiota for stabilizing SOM under plant invasion.

Widespread microplastic pollution in mangrove soils of Todos os Santos Bay, northern Brazil.

Microplastics have been studied in sediments from coastal and aquatic environments, but contamination of mangrove soils is still relatively unknown in most mangroves around the world. In this study, the presence of microplastics was investigated in six mangrove soils around the Todos Santos Bay (TSB), the largest and most important navigable bay on the Brazilian coast. Samples were collected at three depths (surface, 10 cm, and 30 cm) at three different distances from the lower tidal area. Ten grams of soil were sieved in a 150 µm mesh and centrifuged with ZnCl2 solution (density of 1.5 kg dm-3) for the extraction of microplastics. The microplastics were quantified, measured, and described using a systematic photographic method and the ImageJ program. Microplastics were abundant in all samples, with a mean of 10,782 ± 7,671 items kg-1 (max.: 31,087 items kg-1, only one sample <2,000 items kg-1), higher than any other value reported worldwide. The abundances varied among the six mangroves studied, with a predominance of fibers and mean size of 196 µm. Even remote mangroves were highly polluted, reflecting a large dispersion of the pollutants. The abundance did not differ significantly between soil depths, evidencing a continuous input and burial of microplastics in the soil up to 30 cm. The investigation of the source of microplastics and their presence in water and biota is urgent in this Brazilian region, and these results emphasize the need for global actions to protect coastal ecosystems.

Plastic debris in coastal macroalgae.

Macroalgae are the most productive marine macrophytes in the coastal ecosystem. Although plastic debris has been ubiquitously detected in marine animals, little is known about plastic pollution in macroalgae and how they interact with each other. In this study, the occurrence of plastic debris including microplastics was investigated in 5 macroalgae species that are commonly found along the Chinese shorelines. These species consisted of Gracilaria lemaneiformis, Chondrus ocellatus, Ulva lactuca, Ulva prolifera and Saccharina japonica. We categorized the plastic debris into 3 size classes, i.e., macroplastics (>25 mm), mesoplastics (5-25 mm), and microplastics (1 µm-5 mm). It was shown that there were 5 loading patterns of plastic debris interaction with the macroalgae. The 5 patterns included entanglement, adherence, wrapping, embedment, and entrapment by epibionts. According to direct observations through the non-digestion method, all 3 size classes of plastics were found in the macroalgae. The abundances were 0-201.5 (macroplastics), 0-1178.0 (mesoplastics) and 0-355.6 (microplastics) items/kg dry weight, respectively. These plastics were dominated by fibers (52.2%) in shape, 1-5 mm (39.6%) in size, and polystyrene (36.5%) in composition. According to indirect observations through the digestion method, only 2 size classes of plastics were identified in the macroalgae: mesoplastics, 0 to 888.9 items/kg dry weight; microplastics, 148.1 to 5889.0 items/kg dry weight. These plastics were prevailing by fibers (71.5%) in shape, 1-5 mm (52%) in size, and polyester (29.3%) in composition. Furthermore, plastic characteristics in the detected macroalgae were related to their species, sampling regions, and beach types based on the results of similarity and principal component analysis. This study indicated that macroalgae utilized diverse pathways for loading plastics in the coastal environment. Meanwhile, environmental factors significantly influenced the distribution of plastics loaded by macroalgae.

Assessment of ecosystem health of a micro-level Ramsar coastal zone in the Vembanad Lake, Kerala, India.

Health of an ecosystem is very much important as we depend on its goods and services for our existence. Because of this, we need to continuously monitor its health for human benefit and for identifying areas for improvement of our natural systems. The present study tries to assess the condition of a coastal ecosystem within the Vembanad Lake, Kerala, India, using key water quality parameters at micro-level. Principal component analysis identified the minimum required water quality dataset for further analysis and was scored using linear scoring functions. The weighted additive method was used to integrate the individual scores to arrive at a final score representing the ecosystem health. Spline interpolation was applied to develop the ecosystem health map of the study area. Using this method, 35.8% area of the aquatic ecosystem studied was characterized as good, 32.2% as moderate, 26.2% as fair and 5.8% as poor. The assessment results can help the policymakers/managers to make appropriate decisions for the better management of the coastal ecosystems studied. Moreover, this methodology can be replicated for the assessment of coastal regions with similar ecosystem characteristics.

Evaluation, effect and utilization of submarine groundwater discharge for coastal population and ecosystem: A special emphasis on Indian coastline.

Submarine groundwater discharge (SGD) is an important process driven by marine and terrestrial forces. Low tide affects SGD the most, therefore the ideal time to detect SGD is the low tide, especially during spring tide. Techniques to detect and quantify SGD along with the understanding of the related aquifer characteristics is discussed in this study. Scientific community across the world is realizing the importance of studying and mapping SGD because in the scenario of climate change, this part of the global hydrological cycle is an important process and is known to have a significant effect on the marine ecosystem due to nutrient and metal inputs around the region of discharge. Therefore, understanding the processes governing SGD becomes very important. In this review, various components and processes related to SGD (e.g. Submarine Groundwater Recharge, Deep Porewater Upwelling, Recirculated Saline Groundwater Discharge), along with detailed discussion on impacts of SGD for marine ecosystem is presented. Also, it highlights the future research direction and emphasis is put on more research to be done keeping in mind the changing climate and its impacts on SGD.

How sawmill wastes impact surface water, sediment, macrobenthic invertebrates, and fish: a case study of the Lagos lagoon, Okobaba Area, South-western Nigeria.

The Okobaba area of the Lagos Lagoon, Nigeria, is characterised by sawmilling activities which are potential threats to resident aquatic organisms. This study was aimed at evaluating the effect of sawmilling activities on the environmental quality of the Lagos lagoon at Okobaba area, Lagos, Nigeria. Surface water, sediment, macrobenthic invertebrates, and fish species were sampled monthly from six stations for 3 months (July-September 2018). Relevant stakeholders were administered a cross-sectional questionnaire to determine their knowledge of the environmental effects of their activities. Environmental samples were analysed following standard methods. Descriptive and inferential statistics were performed using SPSS 20.0 and PAST 1.97. Results showed that surface water dissolved oxygen and chemical oxygen demand were significantly lower, while sediment total organic matter and nitrates were significantly higher at the test site compared to the reference site. A total of 389 macrobenthic invertebrates comprising eight species and two macrobenthic invertebrates comprising one species as well as 121 fishes comprising nine species and 70 fishes comprising nine (9) species were recorded at the reference and test sites respectively. About 46.3% of respondents alluded to improper waste disposal as the major cause of pollution at the test site among others, 66.7% responded that wastes were disposed of by burning among other disposal methods, and 66.6% agreed that the sawmilling activities contributed to reduction of aquatic animal population. We recommend urgent regulatory intervention to address the indiscriminate discharge of wastes and facilitate adequate environmental risk advocacy to sustain life below water (United Nations Sustainable Development Goal 14).

Experimental evidence of gradual size-dependent shifts in body size and growth of fish in response to warming.

A challenge facing ecologists trying to predict responses to climate change is the few recent analogous conditions to use for comparison. For example, negative relationships between ectotherm body size and temperature are common both across natural thermal gradients and in small-scale experiments. However, it is unknown if short-term body size responses are representative of long-term responses. Moreover, to understand population responses to warming, we must recognize that individual responses to temperature may vary over ontogeny. To enable predictions of how climate warming may affect natural populations, we therefore ask how body size and growth may shift in response to increased temperature over life history, and whether short- and long-term growth responses differ. We addressed these questions using a unique setup with multidecadal artificial heating of an enclosed coastal bay in the Baltic Sea and an adjacent reference area (both with unexploited populations), using before-after control-impact paired time-series analyses. We assembled individual growth trajectories of ~13,000 unique individuals of Eurasian perch and found that body growth increased substantially after warming, but the extent depended on body size: Only among small-bodied perch did growth increase with temperature. Moreover, the strength of this response gradually increased over the 24 year warming period. Our study offers a unique example of how warming can affect fish populations over multiple generations, resulting in gradual changes in body growth, varying as organisms develop. Although increased juvenile growth rates are in line with predictions of the temperature-size rule, the fact that a larger body size at age was maintained over life history contrasts to that same rule. Because the artificially heated area is a contemporary system mimicking a warmer sea, our findings can aid predictions of fish responses to further warming, taking into account that growth responses may vary both over an individual's life history and over time.

Four decades of functional community change reveals gradual trends and low interlinkage across trophic groups in a large marine ecosystem.

The rate at which biological diversity is altered on both land and in the sea, makes temporal community development a critical and fundamental part of understanding global change. With advancements in trait-based approaches, the focus on the impact of temporal change has shifted towards its potential effects on the functioning of the ecosystems. Our mechanistic understanding of and ability to predict community change is still impeded by the lack of knowledge in long-term functional dynamics that span several trophic levels. To address this, we assessed species richness and multiple dimensions of functional diversity and dynamics of two interacting key organism groups in the marine food web: fish and zoobenthos. We utilized unique time series-data spanning four decades, from three environmentally distinct coastal areas in the Baltic Sea, and assembled trait information on six traits per organism group covering aspects of feeding, living habit, reproduction and life history. We identified gradual long-term trends, rather than abrupt changes in functional diversity (trait richness, evenness, dispersion) trait turnover, and overall multi-trait community composition. The linkage between fish and zoobenthic functional community change, in terms of correlation in long-term trends, was weak, with timing of changes being area and trophic group specific. Developments of fish and zoobenthos traits, particularly size (increase in small size for both groups) and feeding habits (e.g. increase in generalist feeding for fish and scavenging or predation for zoobenthos), suggest changes in trophic pathways. We summarize our findings by highlighting three key aspects for understanding functional change across trophic groups: (a) decoupling of species from trait richness, (b) decoupling of richness from density and (c) determining of turnover and multi-trait dynamics. We therefore argue for quantifying change in multiple functional measures to help assessments of biodiversity change move beyond taxonomy and single trophic groups.