Marine Ecology-An Evolutionary Perspective最新文献

This study provides the first detailed assessment of the spatio-temporal distribution of benthic amphipods in Chilika Lagoon. Seasonal changes in species composition, diversity, and distribution were analyzed across four lagoon sectors, along with environmental factors influencing these patterns. Thirteen species belonging to seven genera and families were recorded, with Aoridae, Eriopisidae, and Maeridae being dominant. Permutational Multivariate Analysis of Variance (PERMANOVA) and Canonical Analysis of Principal Coordinates (CAP) analyses revealed clear separation between post-monsoon/winter assemblages and those from pre-monsoon/monsoon seasons. Amphipod communities differed markedly from earlier records, likely due to long-term ecological changes in the lagoon, though Quadrivisio bengalensis and Victoriopisa chilkensis persisted, indicating their resilience. Principal Component Analysis (PCA) and Distance-based Linear Models (DistLM) showed amphipod diversity significantly correlated positively with dissolved oxygen and pH, and negatively with depth and temperature. General Linear Model (GLM) identified dissolved oxygen as the primary driver that can model the amphipod distribution in the studied area. The results of Canonical Correspondence Analysis (CCA) demonstrated that amphipod species show varying degrees of specialization, with F. odishi exhibiting a strong environmental affinity, while most taxa display broader ecological tolerance. In contrast, Quadrivisio bengalensis, Quadrivisio chilikensis, and Ampelisca sp. were associated with higher temperature and higher total organic carbon (TOC). Overall, this study establishes a much-needed ecological baseline for benthic amphipods in Chilika Lagoon, demonstrating the species-specific responses to environmental conditions and offering a framework for detecting future ecological change.

Merluccius productus, commonly referred to as the Pacific Hake, is well known as a relevant species in the structure and functioning of its marine food web networks, acting as a foraging species. Additionally, it represents an important resource for the fishing industry. Nevertheless, little is known about its feeding habits. Therefore, this work describes the diet of the Pacific hake inhabiting the Gulf of California. Samples were obtained from six exploratory fishing research trips conducted between 2014 and 2017. The Prey-Specific Index of Relative Importance (%PSIRI) was used to quantify the dietary components of the Pacific hake. Additionally, to determine its feeding strategy, a similarity analysis was conducted and the Levin's Index and Morisita–Horn Index were calculated. The sampling included 1772 organisms with sizes ranging from 13.3 to 98.4 cm TL. The analysis of 39.2% of stomachs revealed the presence of different prey items, allowing the identification of 23 distinct prey types grouped into three categories: bony fish, crustaceans, and mollusks. The Prey-Specific Index of Relative Importance indicated that the diet is mainly composed of Solenocera mutator (25.2%), fish remains (24.9%), Nyctiphanes simplex (18.7%), and Benthosema panamense (8.3%), collectively accounting for 77.1% of the diet composition. The low Levin's index value (Bi = 0.19) classified the Pacific hake as a specialized predator, while the Morisita–Horn index indicated a moderate level of dietary overlap (Cλ = 0.42). The temporal similarity analysis revealed an overall similarity of 60%, allowing the identification of three distinct groups. Notably, Group B, composed of stomach contents from F-2014 and C-2014, exhibited a higher similarity of 76.1%. The highest contribution to the similarity of this group was represented by the euphausiids N. simplex (41.03%). Our results suggest that M. productus primarily feeds on highly abundant and available prey species in its environment, predominantly pelagic crustaceans, performing vertical migration to feed. The high frequency of crustaceans such as S. mutator and N. simplex, along with the fish B. panamense, further supports the classification of M. productus as a specialized predator.

Hydromedusae are diverse zooplankton that sometimes have great impacts on aquatic ecosystems. We investigated the seasonal occurrences and assemblage structure of hydromedusae in the offshore area of Sagami Bay, central Japan. Throughout the study, 33 holoplanktonic and 9 meroplanktonic hydromedusae species were collected. Unlike the nearshore hydromedusan assemblage, low species richness of meroplanktonic hydromedusae was a characteristic feature offshore. Total abundances drastically changed seasonally, with a spring peak. Muggiaea atlantica, Obelia sp., Solmundella bitentaculata, Rathkea octopunctata, Sugiura chengshanense, Liriope tetraphylla, and Aglaura hemistoma were abundant, with these seven species together comprising 58.7%–97.9% of the hydromedusan assemblage. Seasonal occurrence patterns differed among species. For example, M. atlantica was the most abundant and occurred throughout the year, with a spring peak that was probably affected by water temperature; Obelia sp. showed multiple abundance peaks, which might be driven by advections. A redundancy analysis (RDA) showed that seasonal occurrence of hydromedusae was closely related to both physical and biological factors. Our findings indicate that succession of the offshore hydromedusan assemblage was seasonal, but it was also influenced by short-term hydrographic processes such as the strong intrusion of oceanic water into the bay.

Marine biological invasions are accelerating under the influence of global trade and climate change, posing one of the most pressing threats to ocean biodiversity. This review critically examines the genetic consequences of invasive species in marine ecosystems, with a focus on mechanisms such as hybridization, introgression, genetic homogenization, and population bottlenecks. Invasive species not only disrupt native gene pools through processes such as hybridization and genetic introgression but can also shift evolutionary pathways, reduce adaptive potential, and destabilize ecological networks. Through key case studies including Pterois spp. in coral reefs and Carcinus maenas in estuarine systems, this review highlights the multifaceted genetic impacts across diverse marine environments. It further explores how emerging stressors, such as ocean warming and habitat degradation, intensify these effects. Despite progress in applying next-generation sequencing tools for detection and monitoring, substantial gaps remain in our understanding of invasion dynamics at both genetic and ecosystem levels. The review advocates for a more integrated framework that combines genomic data, policy action, and public engagement to improve invasive species management. Ultimately, this work underscores the urgent need for transdisciplinary strategies to preserve marine genetic diversity and ecosystem resilience in an era of escalating environmental change.

Marine fungi have a crucial but little-studied role in the dynamics of disease, holobiont stability and nutrient cycling in coral reef ecosystems. Despite having more than 1500 identified species, little is known about the ecological roles of marine fungi in comparison to bacteria and algae. Fungal populations live in the surrounding waters, sediments, bones, mucous and coral tissues. Ascomycota, Basidiomycota and Chytridiomycota are among the many phyla that they constitute. These fungi function as mutualists, pathogens, decomposers and bioindicators that influence coral health through food provisioning, antimicrobial activity and stress tolerance. However, when opportunistic species are subjected to environmental stress, they can exacerbate disease. Specifically, warming, acidification, eutrophication, pollution, hypoxia and sedimentation are environmental changes that impact fungal diversity and function. As a result, microbial networks become unstable and more pathogenic. Nutrient turnover and fungus-mediated decomposition impact reef carbon fluxes and ecosystem structure, causing bioerosion and biodiversity loss. Present research is limited by inadequate functional validation, taxonomic and regional biases and a lack of understanding of multi-stressor interactions, microbial networks and pathogen spreading pathways. This study highlights the critical roles that marine fungi play in disease dynamics, nutrient cycling and reef resilience by summarising the research on their interactions with coral. It identifies significant knowledge gaps in the context of global change and offers directions for integrative research that uses omics methods, experimental manipulation and predictive modelling to direct reef management and conservation.

Populations at a species' distribution edges often present reduced gene flow, increased impact of genetic drift, and impoverished genetic variation, globally compromising their ability to adapt to environmental changes. This study assessed the genetic diversity, structure, and connectivity of the Mediterranean endemic seagrass Posidonia oceanica at its easternmost distribution limit, from diverse thermal regimes around Cyprus, contextualised within a set of 16 Turkish populations in the Levantine and Aegean Seas (eastern Mediterranean). The genetic assessments were based on sets of 13 to 16 microsatellite loci, depending on the analysis. Our findings revealed lower genotypic and allelic richness in the Cypriot populations, which also presented lower connectivity and higher differentiation among them in comparison to the Turkish ones. Additionally, the genetic and genotypic diversity and the connectivity of Cypriot populations were highly variable, with populations presenting high diversity and connectivity, while others exhibited extremely low diversity and high isolation. The discrepancies among the Cypriot populations were potentially due to differences in the sexual reproductive output related to the different thermal regimes around the island and the presence of barriers to gene flow along the island's southern coastline. This study advances our understanding of the genetic connectivity and genetic diversity of range-edge P. oceanica populations in the Eastern Mediterranean. This knowledge can guide the management of conservation and ecosystem restoration initiatives for this habitat-forming seagrass species.

Porpita porpita (Linnaeus, 1758), commonly known as the blue button jellyfish, is a pleustonic hydrozoan distributed in tropical and subtropical oceans and occasionally observed in mass strandings. On April 10, 2024, the first mainland beach stranding of this species in southeastern Bangladesh was recorded at Mundar-Deil beach along the Teknaf coast, during a national heatwave. This represents only the second confirmed occurrence of P. porpita in Bangladesh, ~23 km north of the first sighting at St. Martin's Island in 2014. Environmental parameters, including salinity, wind, currents and sea surface temperature were recorded on-site. Morphological and morphometric analyses of 65 collected specimens revealed that the total diameter was significantly correlated (p < 0.05) with the disc diameter (r = 0.981), mantle length (r = 0.895), and the average tentacle length (r = 0.751). Additionally, disc coloration and float structure aided in species verification and ecological interpretation. The occurrence during peak pre-monsoon heat and elevated salinity highlights the species' possible northward latitudinal range shift in response to climate change. This event may be driven by synergistic effects of global warming, monsoonal currents, strong pre-monsoon onshore winds, and declining predation pressure particularly from sea turtles, whose nesting has decreased by over 80% due to entanglement, habitat loss, and predation by feral species. These findings underscore the ecological indicator potential of P. porpita and the need for continued surveillance of gelatinous zooplankton to understand ecosystem responses under warming scenarios in the Bay of Bengal. The presence of P. porpita signals a potential ecological imbalance and suggests that this hydrozoan may serve as an emerging bioindicator of environmental shifts in the Bay of Bengal region.