Salinity Variations Research Articles

Low functional change despite high taxonomic turnover characterizes the Ulva microbiome across a 2000-km salinity gradient.

The green seaweed Ulva relies on associated bacteria for morphogenesis and is an important model to study algal-bacterial interactions. Ulva-associated bacteria exhibit high turnover across environmental gradients, leading to the hypothesis that bacteria contribute to the acclimation potential of the host. However, the functional variation of these bacteria in relation to environmental changes remains unclear. We analyzed 91 Ulva samples across a 2000-kilometer Atlantic-Baltic Sea salinity gradient using metagenomic sequencing. Metabolic reconstruction of 639 metagenome-assembled genomes revealed widespread potential for carbon, nitrogen, sulfur, and vitamin metabolism. Although the R2 value for salinity explained 70% of taxonomic variation, it accounted only for 17% of functional variation. The limited variation was attributed to typical high-salinity bacteria exhibiting enrichment in genes for thiamine, pyridoxal, and betaine biosynthesis, which likely contribute to stress mitigation and osmotic homeostasis in response to salinity variations. Our results emphasize the importance of functional profiling to understand the seaweed holobiont and its collective response to environmental change.

A new vision of the Adriatic Dense Water future under extreme warming

Abstract. We use the Adriatic Sea and Coast (AdriSC) kilometer-scale atmosphere–ocean model to assess the impact of a far-future extreme-warming scenario on the formation, spreading, and accumulation of North Adriatic Dense Water (NAddW) over the entire basin, including the Jabuka Pit accumulation site, and Adriatic Deep Water (AdDW) over the Southern Adriatic Pit (SAP). Our key findings differ from previous studies that used coarser Mediterranean climate models and did not update the thresholds for dense-water and deep-water definitions to account for the far-future background density changes caused by warmer sea surface temperatures. We show that surface buoyancy losses at NAddW generation sites, driven by evaporation, are expected to increase by 15 % under extreme warming, despite a 25 % reduction in the intensity and spatial extent of Bora winds. As a result, future NAddW formation will remain similar to present conditions. However, the volume of dense water in the Jabuka Pit will decrease due to the increased far-future stratification. Additionally, dense-water transport between the Jabuka Pit and the deepest part of the SAP will stop, as future NAddW will be lighter than the AdDW. Regarding Ionian–Adriatic exchanges, extreme warming will not affect the impact of the bimodal oscillation system on the Adriatic salinity variability, but future AdDW dynamics will be determined by density changes in the northern Ionian Sea. Our findings highlight the complexity of climate change impacts on Adriatic atmosphere–ocean processes and the importance of high-resolution models for more accurate far-future projections in the Adriatic Sea.

A Comprehensive Review on Cucurbit Grafting: A Sustainable Approach to Boost Crop Performance

Grafting, which unites the rootstock and scion of a plant, is crucial for combating soil-borne diseases in cucurbitaceous crops such as watermelon, melon, bitter gourd, summer squash and cucumber. Essential due to limited arable land and off-season demand, this technique enhances plant vigour by improving nutrient uptake and providing resistance to soil pathogens, salinity, drought and temperature variations, thereby improving overall yield and fruit quality. Initially implemented in Japan in the late 1990s, grafting significantly affects fruit pH, flavour, sugar content, carotenoids, and texture. Globally, it has been adopted to prevent diseases like fusarium wilt and root-knot nematode. This practice mitigates production losses under adverse conditions and promotes organic, safer vegetables by reducing pesticide residues. Recent advancements in grafting methods and versatile rootstocks further support its widespread use.

Determining microplastics bioaccumulation in Babylonia spirata adopting nuclear analysis technique

The purpose of this study is to measure the bioaccumulation of iodine-131-labeled polystyrene sulfonate as a microplastic model using nuclear techniques. The biokinetic analysis in this study includes bioaccumulation and depuration of iodine-131-labeled polystyrene sulfonate influenced by the variation of seawater salinity and microplastic concentration. Biokinetic calculations include concentration factor, uptake constant, depuration, elimination constant, and biological half-life. The experimental results showed that the highest bioaccumulation of iodine-131-labeled polystyrene sulfonate was found at a salinity of 32 g·L−1 (5.1 × 10 − 5 mL·g−1) and at a microplastic concentration of 3.85 mg·L−1 (2.88 × 10 − 5 mL·g−1). The experimental results show that microplastics were accumulated in B. spirata, and might enter the food chain in the marine ecosystem.

Mineralization Characteristics of the Hokuryu Epithermal Au‐Ag Deposit, Hokkaido, Japan

ABSTRACTVeins intersected by a ~600‐m‐long drill core into the Hokuryu epithermal Au‐Ag deposit in the northeastern part of Hokkaido, Japan, were investigated including mineralogy, texture, quartz composition, and fluid inclusion characteristics, with relation to elevation. Host rocks of these veins are flow‐banded rhyolite, pyroclastic breccia, and andesite and are mainly altered by illite and chlorite. The veins display crustiform and massive macroscopic textures. The crustiform veins generally located at higher elevations, contain Ag‐rich and Au‐Ag‐rich bands. The massive veins are mainly present at lower elevations, and they are generally barren of precious metals. The Ag‐rich bands in the crustiform veins contain mineral assemblage of hessite + sphalerite + pyrite + galena. These minerals, together with anhedral to rhombic adularia, exist within the interstices of quartz that display microspherical texture. The Au‐Ag‐rich bands contain mineral assemblage of electrum ± naumannite‐aguilarite associated with quartz with colloform, ghost‐sphere, and ghost‐bladed textures. Bulk compositions of the veins reflect the ore mineralogy observed in which Ag is strongly correlated with Pb, Te, Zn, Cd, and Bi. The barren massive veins are mainly composed of granular quartz. Textural and mineralogical characteristics of Au‐ and Ag‐bearing bands in the crustiform veins indicate amorphous silica and calcite precursors. Together with the coexistence of adularia, these suggest liquid boiling during vein formation. Quartz associated with Au‐ and Ag‐bearing minerals exhibits blue cathodoluminescence (ca. 400 nm wavelength) triggered by high Al impurity probably due to pH and pressure fluctuations or impurity redistribution during recrystallization from metastable amorphous silica. Fluid inclusions hosted in quartz and adularia, which contain negligible amounts of CO2, show a modal homogenization temperature range of 260°C–290°C and a salinity range of 1.2–6.9 wt% NaCl equivalent. The homogenization temperatures follow a boiling point curve and indicate an erosion of up to ~340 m for the deposit. The variable salinities in relation to elevation suggest extreme vapor loss during boiling at depth, episodic influx of high salinity fluids from deeper source, or mixing with high salinity fluids along anastomosing fractures at relatively shallower depths.

State of knowledge for thermohaline conditions on the shelf of West Kamchatka

All available data on water temperature and salinity for the shelf of West Kamchatka are analyzed and all scientific publications and the most important unpublished thesises concerning this area are summarized. Current ideas about the water masses distribution and seasonal and long-term variability of water temperature and salinity on the shelf are discussed. There is noted that the existing estimates of seasonal and long-term variability of water temperature require significant additions for recent times (last 20 years) and certain spatial areas. Insufficient understanding is revealed for spatial-temporal dynamics of salinity in the mixing zone between the river and sea waters that requires special research.

The Indian Ocean Surface Salinity during El Nio

El Nio (EN) is a critical air-sea interaction that occurs between the atmosphere and the ocean in the tropical eastern Pacific region. Previous studies have classified EN into two main types: the traditional EN and the central Pacific EN. This research uncovers that these EN have substantial impacts on the annual variations in ocean salinity in the equatorial Indian Ocean, particularly during the autumn season in the Northern Hemisphere. During traditional EN, ocean salinity tends to decrease, whereas during central Pacific EN, it increases. A thorough salinity budget analysis was conducted to determine the key drivers influencing changes in Indian Ocean salinity. The results suggest that wind-induced anomalous zonal advection plays a crucial role in these salinity changes, which are further affected by the abnormal zonal circulation patterns across the Indian Ocean.

Rheology as a tool for identifying and characterizing optimal microemulsions formulations

AbstractThis study investigates the use of rheology to detect phase inversion in surfactant–oil–water (SOW) systems, offering a rapid method for identifying “optimal formulations.” Phase inversion through temperature or salinity variation provides a faster alternative compared with equilibrium scans. Using well‐defined polyethoxylated surfactants (C8EO3, C10EO4, C12EO5), phase inversion was monitored through viscosity measurements at a constant shear rate, with temperature as formulation variable. Emulsion viscosity reaches a minimum at the phase inversion point, which corresponds to an ultra‐low interfacial tension condition. A strong correlation between the reported fish‐tail temperature (T*) and the phase inversion temperature (PIT) was observed. While identifying optimal conditions through a formulation scan in a series of test tubes is relatively quick, evaluating the surfactant system's ability to reduce interfacial tension can take several weeks due to the requirement of equilibrium. Formulation conditions at which minimal emulsion viscosity occurs are related to those where three‐phase systems are obtained, with the magnitude of interfacial tension inversely proportional to this value. An empirical approach linking the emulsion destabilization zone with the interfacial tensions is proposed. By measuring this interval, it is possible to roughly predict interfacial tension for model systems.

Assessing the Impact of Climate Change on Salinity Variability in Rivers and Estuaries: A Bayesian Modeling Approach

Assessing the Impact of Climate Change on Salinity Variability in Rivers and Estuaries: A Bayesian Modeling Approach

Effects of the Interaction of Salinity and Rare Earth Elements on the Health of Mytilus galloprovincialis: The Case of Praseodymium and Europium.

The growing use of products containing rare earth elements (REEs) may lead to higher environmental emissions of these elements, which can potentially enter aquatic systems. Praseodymium (Pr) and europium (Eu) are widely used REEs with various applications. However, their ecotoxicological impacts remain largely unexplored, with poorly understood risks to wildlife. Moreover, organisms also face environmental stressors like salinity fluctuations, and the nature of the interaction between salinity variations and contaminants is not yet clear. Therefore, this study aimed to evaluate the influence of salinity shifts on the impacts of Pr and Eu on adult mussels and the sperm of the species Mytilus galloprovincialis after 28 days and 30 min of exposure, respectively. To do so, biochemical and histopathological alterations were evaluated in adults, while biochemical and physiological changes were analysed in sperm. Additionally, the Integrated Biological Index (IBR) was calculated to understand the overall impact of each treatment. The results showed that adult mussels were most affected when exposed to the combination of high salinity and each element, which altered the behaviour of defence mechanisms causing redox imbalance and cellular damage. On the other hand, sperm demonstrated sensitivity to specific REE-salinity combinations, particularly Pr at lower salinity and Eu at higher salinity. These specific treatments elicited changes in sperm motility and velocity: Pr 20 led to a higher production of O2- and a decrease in velocity, while Eu 40 resulted in reduced motility and an increase in irregular movement. At both lower and higher salinity levels, exposure to Eu caused similar sensitivities in adults and sperm, reflected by comparable IBR scores. In contrast, Pr exposure induced greater alterations in sperm than in adult mussels at lower salinity, whereas the reverse was observed at higher salinity. These findings suggest that reproductive success and population dynamics could be modulated by interactions between salinity levels and REE pollution, highlighting the need for further investigation into how REEs and environmental factors interact. This study offers valuable insights to inform policymakers about the potential risks of REE contamination, emphasising the importance of implementing environmental regulations and developing strategies to mitigate the impact of these pollutants.

Long-Term Stable Reference Electrodes with High-Pressure Tolerance and Salinity-Independence.

The reference electrode's performance is essential for ensuring the accuracy of electrochemical sensors in marine environments. Yet, the many existing reference electrodes can exhibit sensitivity to salinity variations, potentially leading to inaccuracies in the measurement process. Herein, we have designed a reliable solid-state reference electrode by introducing SiOx-stabilized 1-methyl-3-octylimidazolium bis(trifluoromethyl sulfonyl)imide ([C8mim+] [Ntf2-]) into a P(VdF-co-HFP) matrix with a SPEEK/[C8mim+] [Ntf2-] coated Ag/AgCl as substrate. The SPEEK/[C8mim+] [Ntf2-] coating protects the AgCl substrate, and the incorporation of SiOx improves the compatibility of the IL with the polymer matrix, thereby increasing the electrode's resistance to interference and extending its long-term stability and lifespan. The developed reference electrode showed a stable and rapid response, with potential variations of less than 0.7 mV across various salinity solutions, including practical seawater, lake water, and their mixture samples. During extended periods of 18 days in deionized water and artificial seawater, the electrode demonstrated negligible potential drifts of 0.36 and 0.14 mV/d, respectively. Notably, the electrode could maintain a stable potential even after being stored in a preservative solution for 67 days. Furthermore, the electrode showed a stable response to withstand pressures of up to 100 MPa, covering the vast majority of the seafloor. This innovative reference electrode is capable of maintaining a stable reference potential across various salinities, ionic strength, and full ocean depth, making it versatile for use in diverse aquatic environments, underscoring its significant potential for advancing oceanographic research and enabling new insights into the unexplored depths of oceans.

The role of spirulina in food security: Nutritional and ecological implications in the context of climate change

Abstract In the context of a changing climate and the goal of achieving carbon neutrality by 2050, microalgae, particularly spirulina, are emerging as a versatile and sustainable solution to ensure food security, serving as an alternative protein source for human consumption. Spirulina can absorb carbon dioxide during photosynthesis, grows rapidly, does not require arable land, is cultivated year-round, and is rich in protein as well as other macro- and micronutrients. Spirulina stands out not only for its resilience and adaptability to a range of environmental conditions – including variations in light, temperature, pH, and salinity – but also for its low water requirements, making it a promising option for regions with limited water resources. It can address food security challenges by providing nutritional benefits as a dietary supplement and enhancing animal feed quality. Additionally, it supports sustainable agriculture as a biostimulant, improving crop productivity and soil health while reducing reliance on chemical inputs. Its potential as a raw material across various industries and the exploration of new applications make spirulina an attractive candidate for future research, which should focus on enhanced profitability and large-scale accessibility.

Performance of Corrosion Behavior of Commercial Magnesium Alloy Anode Electrode in Seawater-Powered Lamps

In modern times, alternative technologies that are efficient and environmentally friendly continue to be developed, such as lamps fueled by seawater. By reacting between a magnesium alloy anode electrode and an electrolyte solution of salt, a difference in electrical potential is generated, which can power electronic equipment. In order to achieve optimal performance with the magnesium alloy anode electrode, an initial assessment of this component is necessary. This research discusses the corrosion behavior of the magnesium alloy anode electrode caused by variations in salinity in seawater batteries. In this study, five samples of commercial product anode electrodes were prepared. Each sample was immersed in a salt solution with different salt concentrations. The salt solution was prepared by mixing 380 ml of distilled water with salt masses of 14g, 16g, 18g, 20g, and 22g respectively. Potentiodynamic testing was conducted in this research. The results showed that the corrosion behavior produced from the five samples yielded the highest corrosion potential, electrical current, and corrosion rate values of (Ecorr = 1.5419 Volts), (Icorr = 0.0010 Amps/cm2), and 12.5850 mm/a, respectively. These results indicate an increase in corrosion rate with increasing salinity. It is hoped that in future research, additional treatments will be applied to the electrode to achieve better performance.

Exchange flow in a highly stratified fjord in drought conditions

Fjords are known for their biodiversity and abundant aquaculture resources. However, climate and anthropogenic pressures are altering fjord biological, physical, and chemical processes that will undoubtedly change the ecosystem as a whole. To investigate the impact of climate change on fjord functioning, this study examines the impacts of drought conditions on the physical dynamics and salinity variations in a fjord known for its bolstering aquaculture industry in Northern Chilean Patagonia, the Reloncaví Fjord (41.5° S). Using a high-resolution hydrodynamic model and the Total Exchange Flow (TEF) framework, we analyzed the impacts of river discharge, tides, and wind during a dry year (2016) and a typical year (2018). In 2016, reduced freshwater input decreased exchange flow and increased salinity compared to 2018. In 2018, river discharge dominated TEF variability (74%), while tides and wind contributed 17% and 9%, respectively. In summer 2016, tidal and wind influences rose to 21% and 16%, highlighting their role under low freshwater conditions. Increased wind facilitated destratification, mixing high-salinity subsurface waters with fresh surface layers, affecting ecosystem dynamics. From these results we developed a method to predict long-term stratification variability (1980–2021), identifying critical ecological shifts. Logistic regression models showed significant links between stratification levels and harmful algal blooms (HABs) of Pseudchatonella spp. and Alexandrium catenella. Lower stratification was linked to higher Pseudchatonella spp. HABs in summer, while higher stratification correlated with Alexandrium catenella blooms in spring, tied to increased river discharge. These results suggest that severe HAB events in Northern Patagonia may become more frequent with climate change, underscoring the need to consider local environmental dynamics and stratification in HAB studies.

Limited Microbial Contribution in Salt Lake Sediment and Water to Each Other's Microbial Communities.

Climate change and human activities have led to frequent exchanges of sedimentary and aquatic microorganisms in lakes. However, the ability of these microorganisms to survive in their respective habitats between saline lake sediment and water remains unclear. In this study, we investigated microbial sources and community composition and metabolic functions in sediments and water in Yuncheng Salt Lake using a combination of source tracking and Illumina MiSeq sequencing. The results showed that 0.10-8.47% of the microbial communities in the sediment came from the corresponding water bodies, while 0.12-10.78% of the sedimentary microorganisms contributed to the aquatic microbial populations, and the microbial contributions depended on the salinity difference between sediment and water. Habitat heterogeneity and salinity variations led to the differences in microbial diversity, community composition, and assembly between sediment and water communities. The assembly of sedimentary communities was mainly controlled by stochastic processes (>59%), whereas the assembly of aquatic communities was mainly controlled by deterministic processes (>88%). Furthermore, sediments had a higher potential for metabolic pathways related to specific biogeochemical functions than lake water. These results provide insights into the survival ability of microorganisms and the mechanisms of microbial community assembly under frequent exchange conditions in saline lakes.

Statistical approach to the monitoring of groundwater quality for drinking in Northern Algeria

The scarcity of surface water during prolonged droughts makes the Mitidja quaternary aquifer in north-central Algeria essential for drinking water supply. This study aims to improve understanding of the hydrochemical behavior of this aquifer using multivariate statistical analysis. The main objective is to identify the factors influencing the chemical composition of the water and determine its suitability for domestic use. To this end, water samples were taken from 20 boreholes and analyzed for electrical conductivity, pH, and significant ions during the dry and wet seasons. The results showed significant spatial variations in salinity, particularly in the plain's extreme eastern and western regions, where several parameters exceeded WHO standards. Chemical quality was higher in the western and central boreholes than in those to the east, which were deemed unsuitable for human consumption. Various chemical facies result from the dissolution of dolomitic and evaporitic formations, leading to increased mineralization. In addition, human activity has affected water quality, notably through the excessive use of chemical fertilizers and the discharge of untreated wastewater. This study underlines the need for sustainable environmental management to preserve water quality in the Mitidja quaternary aquifer, which is essential for guaranteeing local communities' drinking water access.

Salinity Effects on Soil Structure and Hydraulic Properties: Implications for Pedotransfer Functions in Coastal Areas

Understanding the effects of salinity on soil structure and hydraulic properties is critical for addressing environmental challenges in coastal saline and sodic areas. In this study, soil samples were collected from a coastal region in eastern China to investigate how salinity affected the soil structure and hydraulic properties based on lab experiments. A comprehensive soil dataset was also compiled from the experimental results to develop a salinity-based pedotransfer function (PTF-S) tailored to the coastal environment. The results showed that salinity significantly altered the soil aggregate size distribution and hydraulic properties. Higher salinity promoted the formation of larger aggregates (0.25–2 mm), particularly in silty clay soil. Salinity positively correlated with the saturated hydraulic conductivity (Ks) in sandy loam soil, regardless of the cation type (Na⁺ or Ca2⁺). By comparison, Na+ increased the Ks of silty clay soil up to a certain threshold, while Ca2+ enhanced the Ks regardless of the soil texture. Increased salinity also reduced the soil water retention of sandy loam soil; however, Na+ increased the soil water retention of silty clay soil and Ca2+ had different effects depending on the suction levels. The newly developed PTF-S model, which included the electrical conductivity (EC) and cation exchange capacity (CEC), showed better predictions for the volumetric water content (R = 0.886 and RMSE = 0.057 cm3/cm3) and log Ks (R = 0.991 and RMSE = 0.073 mm/h) than the traditional model that excludes the salinity variables EC and CEC (PTF-N) (R = 0.839 and RMSE = 0.066 cm3/cm3 for the volumetric water content, and R = 0.966 and RMSE = 0.140 mm/h for the log Ks). This study highlights the importance of developing salinity-based PTFs for addressing soil salinization challenges.

Reconstructing the Ocean State Using Argo Data and a Data-Driven Method

Abstract Over the past two decades, Argo profiles have provided unprecedented insight into the global patterns of space and time variability of ocean temperature and salinity, significantly reducing associated uncertainties. However, analyzing such assessments during the pre-Argo period remains challenging due to the scarcity of observations in many regions. From the Argo period, a set of dominant three-dimensional patterns can be estimated using empirical orthogonal function (EOF) analysis, which helps to fill in observational gaps. From the associated principal components, temporal fluctuations can be observed, aiming to build a catalog of possible ocean state trajectories. To map pre-Argo observations, EOFs are used in a data assimilation framework that uses this catalog to feed an analog prediction and provide reanalysis. In this study, a new data-driven interpolation method called Reduced-Space Analog Data Assimilation (RedAnDA) was tested in the tropical Pacific Ocean. RedAnDA was first validated through an observing system simulation experiment (OSSE) approach, using synthetic observations extracted from a model simulation. It was subsequently applied to a real historical dataset and compared with other available reanalysis products. Overall, the reconstructed temperature field showed variability consistent with the OSSE true field and other reanalysis products in the real data application. Further improvements are needed to optimally estimate uncertainty, but RedAnDA already combines valuable information about state predictability, observational sampling, and unresolved scale issues.

Influence of river runoff and precipitation on the seasonal and interannual variability of sea surface salinity in the eastern North Tropical Atlantic

Abstract. In tropical regions, the freshwater flux entering the ocean originates primarily from precipitation and, to a lesser extent when considering basin-scale averages, from continental rivers. Nevertheless, at the regional scale, river flows can have a significant impact on the surface ocean dynamics. Riverine freshwater modifies salinity and, therefore, density, stratification, and circulation. With its particular coastline and high cumulative river discharge, as well as its being in the vicinity of the intertropical convergence zone (ITCZ), the eastern part of the North Tropical Atlantic (e-NTA) region off northwestern Africa is a particularly interesting location to study the linkage between precipitation, river outflow, and sea surface salinity (SSS). Here, we focus on the regional e-NTA SSS seasonal cycle and interannual variability and on the impact of using various river runoff and precipitation forcing data sets to simulate SSS with a regional model. The simulated SSS values are compared with the Climate Change Initiative (CCI) satellite SSS values; in situ SSS values from Argo floats, ships, and a coastal mooring; and the GLORYS reanalysis SSS values. An analysis of the mixed-layer salinity budget is then conducted. Overall, the simulations reproduce the seasonal cycle and interannual variability well despite a positive mean model bias north of 15° N. The seasonal cycle is impacted by the phasing of the different runoff products. The mixed-layer SSS decrease during the rainy season is mainly driven by precipitation followed by runoff by means of horizontal advection and is partly compensated for by vertical mixing. In terms of interannual anomalies, river runoff has a more direct impact on SSS than precipitation. This study highlights the importance of properly constraining river runoff and precipitation to simulate realistic SSS values and the importance of observing SSS in coastal regions to validate such constraints.

Continental freshwater discharge influences sea surface salinity variability near world’s megadeltas

Sea surface salinity ([Formula: see text]) is a key parameter in the thermohaline circulation of global oceans. Near the megadeltas, inland streamflow through large catchments plays a crucial role in mediating salinity. While some regional studies have investigated how [Formula: see text] is impacted through water cycle and climate components, a global scale quantification of inland streamflow contribution on [Formula: see text] variability is lacking. Here, we utilized remote sensing and observation-driven datasets to quantify the statistical associations between [Formula: see text] and streamflow ([Formula: see text]) at 48 megadeltas worldwide. This study uncovers a robust negative association between [Formula: see text] and [Formula: see text], with correlation coefficients [Formula: see text] less than [Formula: see text] for seasonal data found in 26 of the 48 megadeltas, and less than [Formula: see text] for deseasoned data in 21 megadeltas. The anticorrelation relationship is more pronounced in large deltas, particularly near tropical climates and in river-influenced deltas. The study also underscores the significant roles of climate, morphological, and anthropogenic stratification in impacting the natural influence of freshwater discharge on SSS. By highlighting the interconnected impacts of alterations in terrestrial water cycle upstream and [Formula: see text], this work contributes to enhancing our understanding of global ocean and climate circulation patterns and in tackling environmental issues pertaining to marine ecosystems.