Advances in marine biology最新文献

Marine space is three dimensional, the turnover of life forms is rapid, defining a fourth dimension: time. The definition of ecologically significant spatial units calls for the spatio-temporal framing of significant ecological connections in terms of extra-specific (biogeochemical cycles), intra-specific (life cycles), and inter-specific (food webs) fluxes. The oceanic volume can be split in sub-systems that can be further divided into smaller sub-units where ecosystem processes are highly integrated. The volumes where oceanographic and ecological processes take place are splittable into hot spots of ecosystem functioning, e.g., upwelling currents triggering plankton blooms, whose products are then distributed by horizontal currents, so defining Cells of Ecosystem Functioning (CEFs), whose identification requires the collaboration of physical and chemical oceanography, biogeochemistry, marine geology, plankton, nekton and benthos ecology and biology, food web dynamics, marine biogeography. CEFs are fuzzy objects that reflect the instability of marine systems.

There have been multiple paternity studies across many taxa, including birds, reptiles and insects, for many decades. Sea turtles are by far the most studied of any group of reptiles with up to ten fathers recorded for a clutch and multiple paternity in over 90% of clutches in some populations. Whether multiple paternity has any adaptive significance remains a key question in sea turtles, since the impact of environmental conditions often seems to swamp any impact of the incidence of multiple paternity. Climate warming and the resulting threat of feminisation of sea turtle populations is set to provide an intense new focus for studies. If male turtles become increasingly scarce as a result of warming incubation temperatures, then management intervention will be needed to promote male hatchling production. Multiple paternity studies may help inform when intervention is needed, with the expectation that the incidence of multiple paternity will decline as breeding males become scarce.

To persist in an ocean changing in temperature, pH and other stressors related to climate change, many marine species will likely need to acclimatize or adapt to avoid extinction. If marine populations possess adequate genetic variation in tolerance to climate change stressors, species might be able to adapt to environmental change. Marine climate change research is moving away from single life stage studies where individuals are directly placed into projected scenarios ('future shock' approach), to focus on the adaptive potential of populations in an ocean that will gradually change over coming decades. This review summarizes studies that consider the adaptive potential of marine invertebrates to climate change stressors and the methods that have been applied to this research, including quantitative genetics, laboratory selection studies and trans- and multigenerational experiments. Phenotypic plasticity is likely to contribute to population persistence providing time for genetic adaptation to occur. Transgenerational and epigenetic effects indicate that the environmental and physiological history of the parents can affect offspring performance. There is a need for long-term, multigenerational experiments to determine the influence of phenotypic plasticity, genetic variation and transgenerational effects on species' capacity to persist in a changing ocean. However, multigenerational studies are only practicable for short generation species. Consideration of multiple morphological and physiological traits, including changes in molecular processes (eg, DNA methylation) and long-term studies that facilitate acclimatization will be essential in making informed predictions of how the seascape and marine communities will be altered by climate change.

The genus Kogia includes two extant species, the dwarf sperm whale (Kogia sima) and the pygmy sperm whales (K. breviceps). Due to their elusive behavior at the surface, which limits opportunities for observation, they are amongst the least known species of cetaceans and knowledge of their ecology mostly comes from stranded individuals. Although they have overlapping ranges, dwarf sperm whales seem to be distributed preferentially in warmer tropical and subtropical waters, while pygmy sperm whales tend to be associated with more temperate waters. Both species have previously been recorded in the western Indian Ocean, but little is known about their distribution patterns. Data from different sources, including vessel-based and aerial surveys, environmental DNA and strandings were compiled to report on the occurrence of Kogia around the remote oceanic island of Reunion. The combination of sightings data, eDNA detections and stranding events indicated that the dwarf sperm whale was more common than the pygmy sperm whale and seems to use the territorial waters of Reunion on a regular basis. The northern part of the island in particular might provide suitable habitats for the species. Groups of 1-5 individuals were sighted and occurred mainly over the insular slope, in 1310 m deep waters and 8.2 km from the shore on average; no clear seasonality pattern could be determined. Stranding data were consistent with a calving period during the austral summer and highlighted the vulnerability of these species to human activities.

Human activity is generating an excess of atmospheric CO₂, resulting in what we know as ocean acidification, which produces changes in marine ecosystems. Until recently, most of the research in this area had been done under small-scale, laboratory conditions, using few variables, few species and few life cycle stages. These limitations raise questions about the reproducibility of the environment and about the importance of indirect effects and synergies in the final results of these experiments. One way to address these experimental problems is by conducting studies in situ, in natural areas where expected future pH conditions already occur, such as CO₂ vent systems. In the present work, we compile and discuss the latest research carried out in these natural laboratories, with the objective to summarize their advantages and disadvantages for research to improve these investigations so they can better help us understand how the oceans of the future will change.

Natural acidified marine systems (ASs) are environments with relatively low pH levels due to natural causes such as volcanic activity, geochemical reactions, and biological processes. These systems act as natural laboratories for the study of the effects of ocean acidification, allowing for the observation of long-term ecological and evolutionary responses. Understanding these systems is crucial for predicting the effects of anthropogenic ocean acidification (OA) on marine ecosystems. There are 23 ASs in which scientific research has shown significant parallelisms in their results worldwide, such as the disappearance of calcareous organisms and the loss of species with key ecological functions under OA conditions. Future research should emphasize continuous collaboration among teams, as well as public access to oceanographic and biological data along with the monitoring of environmental variables at each AS. To preserve these areas, it is imperative to employ non-destructive methods and protect them as human heritage sites.

The substantial development of microscopic techniques and histological examination methods during the past five decades allowed for many new insights into the histology and microanatomy of Rhizostomeae. The present review focuses on new findings about histologically important structures: nerves, senses, muscles, gonads, zooxanthellae and nematocysts. Different ontogenetic stages of rhizostome species were included in the literature research, supplemented with the authors' unpublished data and figures. The overview of the research results reveals that the application of chemo- and immunohistochemical techniques have provided deeper insights into neuronal and sensory structures and their interconnections. Modern microscopic methods led to new findings on the histological gonadal organization and details of the processes of gametogenesis, fertilization, cleavage, gastrulation, and brooding. Advanced optical methods also allowed for a better understanding of Rhizostomeae-zooxanthellae associations and the morphology and function of nematocysts. Improvements in molecular biology allowed for more precise identification of zooxanthellae associated with rhizostome species. Although there has been significant progress in all of the research subjects covered here, we identify several knowledge gaps and conclude with some recommendations for future research.

While jellyfish are often considered to be a nuisance, their value to ecosystems and for human exploitation is shifting this perception. People have been eating jellyfish for millennia. In recent decades, the scale of jellyfish fisheries has expanded dramatically, with annual catches in the hundreds of thousands of tonnes. The overwhelming majority of jellyfish species targeted for human consumption are from the order Rhizostomeae, which can also be fed to livestock and certain species in mariculture operations. The use of rhizostome jellyfish is expanding beyond food applications, such as pharmaceuticals and cosmetics, especially for collagen and other bioactive compounds. Jellyfish collagen is high in antioxidants, can act as an immunostimulator, and has applications for tissue engineering and medical implements. Jellyfish venom extracts exhibit high biological activities, including those that are antihypertensive, antimicrobial, and anticancer. Jellyfish can also be used as fertilizers and insecticides, and jellyfish mucus appears to have potential as a filter for nanoparticles and microplastics, suggesting possible applications in wastewater treatment. Most of these applications are still in developmental stages, and beyond their use as food, jellyfish are not targeted at commercial scale, apart from collagen extraction. As research advances, exploitation of jellyfish is expected to continue expanding. Given the lack of knowledge and understanding regarding jellyfish fisheries and their management, caution should be exhibited to avoid overfishing.

The genus Kogia includes two species that are some of the least known cetacean species around the globe. Here, we investigated the occurrence, behavior, and habitat suitability of dwarf sperm whales (K. sima) off St. Vincent and the Grenadines (Eastern Caribbean). Small boat dedicated surveys were conducted during May and June of both 2022 and 2023 along the south and west coast of the island of St. Vincent. A total of 2260 km was surveyed and 33 sightings of dwarf sperm whale were recorded, which was also the most frequently sighted cetacean species (37.5% of all cetacean sightings). Group size varied from 1 to 20 individuals (mean = 2.08, SD = 3.23). Traveling and breaching were the most commonly recorded behavioral categories and occurred at an equal proportion (28.6%). The distribution of dwarf sperm whales was restricted to the south and southwest portion of St. Vincent in depths ranging from 95 to 1104 m (mean = 650 m). Habitat suitability (in relation to depth and slope) was investigated using an ensemble model using three algorithms (GLM, GAM, and MaxEnt). The model revealed that slope, and to a lesser extent depth, were important in explaining the habitat suitability of dwarf sperm whales. This preliminary research highlights the existence of a globally important area for dwarf sperm whales off St. Vincent, where encounter rates are significantly higher than in any other known island-associated habitat.

Cetaceans are a critical component of marine ecosystems, acting as top predators in mesopelagic trophic webs. In the Macaronesian biogeographical region, cetacean populations face threats from various anthropogenic activities. Evaluating cryptic oceanic species like kogiids whales is challenging due to insufficient biological and ecological data, making conservation assessments and management efforts harder to achieve. Kogia breviceps and K. sima comprising the family Kogiidae, are morphologically similar, widely distributed, and elusive, with most information originating from stranded specimens and few at sea observations. This study examines data from Kogia species stranded in the Canary Islands between 1977 and 2024 and analyzes sighting data obtained between 1999 and 2024. Between 1977 and May 2024, there were 111 stranding events involving 114 kogiid individuals along the Canary Islands' coasts: 86 events (88 individuals) were pygmy sperm whales, 14 events (15 individuals) were dwarf sperm whales, and 11 events with 11 individuals, were unidentified Kogia species. Additionally, 36 kogiid sightings were recorded, of which 34 originated from dedicated surveys and 2 from opportunistic sightings. Of these sightings, 14 (39%) were K. breviceps, 9 (25%) were K. sima, and 13 (36%) were unidentified Kogia. Twenty-nine sightings (80.5%) of kogiids were recorded in the waters off the eastern coast of the islands of Lanzarote and Fuerteventura. The data indicate that the waters around the Canary Islands are an important habitat for Kogia whales. The findings establish a baseline for future research and underscore the necessity of accurately assessing conservation pressures on pygmy and dwarf sperm whales in the region.