47242 research outputs found
Sort by
Microbiota associated with echinoid eggs and the implications for maternal provisioning
No full textMothers impact the survival and performance of their offspring through the resources they provision, and the degree of maternal investment in an individual offspring can be broadly estimated by egg size for organisms that lack parental care. Animals may also actively maintain symbiotic partnerships with microorganisms through the germ line, but whether microbes are a fundamental component of maternal provisioning is an untested hypothesis in evolutionary symbiosis. We present a preliminary test of this by comparing the egg-associated microbiota of ten sea urchin species with ecological factors known to influence egg size. We found that the microbiota associated with sea urchin eggs had a phylogenetic signal in both composition and richness, which varied between years but not between individuals or within a clutch. Moreover, we found a negative correlation between microbiome richness and taxonomic dominance, and that community diversity covaried with egg size and energetic content but not with pelagic larval duration or latitude. These data suggest that there are multiple parallels between the ecological factors that govern changes in egg size and microbiome composition and diversity, implying that microbial symbionts may be another constituent potentially provided by the mother
Insights on the role of alkaline magmatic systems for epithermal gold potentials : a case study of Conical Seamount, Papua New Guinea
No full textAlkaline porphyry-epithermal systems represent main gold sources throughout the world. The Tabar-Lihir-Tanga-Feni (TLTF) island chain in north-eastern Papua New Guinea exhibits a particular metal endowment, especially exemplified by the giant Ladolam gold deposit on-shore Lihir island with more than 47.1 Mt Measured and Indicated Resources. In the past decades, increased attention has been given to the seamounts off-shore Lihir. Conical Seamount, located south to Lihir, has been well documented because of the hosting gold-mineralization, which is the site where epithermal-style mineralization was discovered on the seafloor first.
However, the magmatic system of Conical Seamount underlying such a prominent gold mineralization has not been well constrained and remained widely unknown. This work identifies and describes the main stages of magmatic evolution underneath Conical Seamount along with their importance for the metal transport and deposition. In a broader context, this study addresses the strong link between alkaline magmas and epithermal mineralization.
A detailed petrographic study combined with geochemical measurements of different magmatic samples recovered during several cruises conducted with the research vessel SONNE (SO94, SO133, SO166 and SO299) was carried out.
Conical Seamount is characterized by several key features for the metal enrichment, transport and deposition: subduction-modified mantle source, significant fractional crystallization, shallow magma chamber marked by metal extraction through sulfide precipitation and fluid exsolution. However, magmatic rejuvenation through the ascent of a new, more hydrous parental magma appears to be an additional necessary stage prior to epithermal mineralization
Food fall-specific scavenging response to experimental medium-sized carcasses in the deep sea
No full textIn the deep sea, benthic communities largely depend on organic material from the overlying water column for food. The remains of organisms on the seafloor (food falls) create areas of organic enrichment that attract scavengers. The scavenging rates and communities of food falls of medium-sized squid, fish and jellyfish (1-100 cm) are poorly known. To test our hypothesis that scavenging responses are specific for different food falls, we deployed camera landers baited with squid, jellyfish and fish for 9 to 25 h at 1360 to 1440 m in the southern Norwegian Sea. Image analysis of 8 deployments showed rapid food fall consumption (20.3 +/- 1.4 [SD] to 31.6 +/- 3.7 g h(-1)) by an amphipod-dominated scavenging community that was significantly different between the food fall types. Fish and squid carcasses were mostly attended by amphipods of the genus Eurythenes. Smaller unidentified amphipods dominated the jellyfish experiments together with brittle stars (cf. Ophiocten gracilis) and decapod shrimps (cf. Bythocaris spp.); the latter only occurred on jellyfish carcasses. The removal time for jellyfish (similar to 17 h) was almost twice as long as that for squid and fish (9-10 h). The maximum scavenger abundance was significantly higher on fish carcasses than on jellyfish and squid. The times at which abundances peaked were similar for jellyfish and fish (after 8-9 h) but significantly sooner for squid (3.00 +/- 0.35 h). Our results, although based on a small number of experiments, demonstrate differences in scavenging responses between food fall species, suggesting tight coupling between the diversity and ecology of benthic scavenging communities in the Norwegian Sea
Identifying a sustainable operating window for seaweed aquaculture in the Global North: balancing expansion barriers and carrying capacity
No full textHighlights:
• Holistic framework for the sustainable window of production for seaweed aquaculture.
• Interdisciplinary expert identified barriers to expansion and carrying capacity.
• List of barriers and impacts with indicators and suggestions for thresholds.
• We highlight the importance of socio-economic aspects for aquaculture sustainability.
Seaweed aquaculture is a growing blue sector that provides many benefits to society (e.g. biomass provision for food, feed and cosmetics) and the environment (e.g. eutrophication mitigation, carbon uptake and habitat provision). Successful and sustainable production expansion requires that these activities are operated within limits of acceptable change (LAC) i.e. align with ecological and social carrying capacity. Emerging from a three-round Delphi study, this work presents, from a Global North perspective, the most relevant 1) limiting variables from the socio-environmental spheres that influence the cultivation unit (inputs), such as high operating costs or underdeveloped markets or uncertain impacts from climate change, and 2) the negative impacts of aquaculture on environment and society (outputs), such as overhyped and unrealistic expectation for seaweed cultivation, conflicts with fisheries or pollution. Consolidated lists of these inputs and outputs are accompanied by specific thresholds beyond which unacceptable changes are likely to occur. These results are placed into a globally applicable holistic framework for a multidimensional assessment of seaweed aquaculture including barriers and carrying capacity, which has been outlined for the first time for seaweed cultivation. Our results emphasize the need to include socio-economic aspects into ecosystem approaches, like profitability or social license to operate – and the need for broad stakeholder participation. This study provides thus a directly useable lists of aspects to consider for cultivators and decision-makers. And as is as such a crucial contribution for the ongoing discourse on sustainable growth of this emerging blue sector. © 2025 The Author
Assessment of carrying capacity and management practices for Litopenaeus vannamei industrialized aquaculture based on an ecosystem model
No full textHighlights:
• An ecosystem model was developed for the indoor industrialized aquaculture system.
• Model captured shrimp growth and nutrient dynamics (nitrogen, phosphorus).
• The system's carrying capacity was assessed based on the discharge standard.
• Evaluated feed quality, water exchange and tailwater treatment effects on system.
• Tailwater treatment maximized carrying capacity and minimized nutrient discharges.
Abstract:
The sustainability of indoor industrialized aquaculture is challenged by resource limitations and environmental constraints. Thus, an integrated ecosystem-level assessment is essential to conserve water resources, improve production efficiency, and enhance the sustainability of the system. In this study, an ecosystem model for a Litopenaeus vannamei industrialized aquaculture system was developed to simulate shrimp growth, and its effects on nitrogen and phosphorus dynamics were examined. This study assessed the carrying capacity of the system, overall benefits, and the effects of management practices by integrating model simulations with discharge standards for nitrogen and phosphorus in tailwater. The results revealed a carrying capacity of 409 ind·m−2 for juvenile shrimp (body length: 4.24 ± 0.37 cm). Compared with the current stocking density (880 ind·m−2), the yield and economic benefit decreased by 53.5 % and 71.5 %, respectively. A simulation of management practices indicated that the carrying capacity could be increased to 449 ind·m−2, 593 ind·m−2, and 1193 ind·m−2 by enhancing feed quality, increasing the water exchange rate, and adopting tailwater treatment technology, respectively. Notably, adopting tailwater treatment technology would increase current stocking density to 1193 ind·m−2 and produce an increase of 33.5 % in economic benefit, a reduction of 26.2 % in tailwater discharge per unit yield, and 48.2 % and 49.0 % reductions in the discharge of total nitrogen and total phosphorus in tailwater, demonstrating water conservation and pollution control. This study provides a theoretical foundation and practical references for the standard discharge of tailwater and efficient resource utilization in L. vannamei industrialized aquaculture systems
Generative artificial intelligence and marine ecological monitoring
No full textTo meet the needs of the future, marine environmental monitoring must develop methods to efficiently combine and utilise data from a diverse range of sources (e.g., satellite imagery, sensor networks, acoustic data). Generative Artificial Intelligence (GenAI) is uniquely suited to aid with this by enabling the synthesis and integration of heterogeneous and often incomplete data. Its ability to learn underlying statistical patterns supports data fusion, imputation, and enhanced interpretation across sources. GenAI also introduces novel modelling approaches to tackle ecological uncertainties and improve predictive insight. Here, we present a comprehensive overview of GenAI applications in marine ecological monitoring, emphasising its potential to improve data quality control, automate species identification, and support the creation of digital twins. We also highlight key research challenges, such as managing model bias and ensuring system transparency, and outline future directions for integrating GenAI into sustainable marine ecological monitoring and management
Seamounts of Cabo Verde: A review of their ecological and economic significance, anthropogenic impacts, and conservation needs
No full textHighlights
• Seamounts around Cabo Verde are severely understudied in all aspects of their marine ecosystem.
• Faunal communities (benthic, pelagic, mobile megafauna) are abundant and diverse, with potential for endemism.
• Cabo Verde seamounts deliver extensive ecosystem services, particularly food provision through fisheries.
• Expected future increases in anthropogenic impacts necessitate urgent development of a conservation plan.
• Effective conservation will need dialogue, strong laws, and resources for enforcement, management, and monitoring.
Abstract
The deep-sea areas of the Cabo Verde Archipelago remain largely unexplored, with seamounts standing out as the most prominent and abundant geomorphological features. The ecological significance of these underwater structures is well-documented in various regions of the planet, as they often serve as biodiversity hotspots, stepping stones for species connectivity and, in some cases, areas with high levels of endemism. However, the biology and ecology of the seamounts around Cabo Verde are still largely unknown. Preliminary studies of the geomorphology, oceanographic characteristics and ecology of specific features suggest that the Cabo Verde seamount network — comprising 14 known conspicuous seamounts as well as smaller elevations less than 1000 m — harbours high biological diversity. That biodiversity associated with the Cabo Verde seamounts spans a wide range of forms, from microscopic organisms to cetaceans, encompassing both pelagic and benthic communities. Commercial activities associated with seamounts, in particular fishing, are a critical aspect to consider for ecosystem management. Evaluating their current uses, future prospects, and the existing and potential threats the Cabo Verde seamounts face is essential for effective and sustainable marine spatial planning. This study reviews and synthesises the current knowledge on the Cabo Verde seamounts within its Exclusive Economic Zone (EEZ), focusing on their environmental and biological aspects, including geology, oceanography, and associated biological communities. Key topics include primary production, zooplankton communities, benthic organisms, large vertebrates such as elasmobranchs, sea turtles, seabirds, and cetaceans, as well as microbes and trophic linkages. Additionally, this review explores the socio-economic dimensions linked to seamounts, highlighting their importance to the local economy and emphasizing the need for effective marine spatial management plans. These considerations are crucial for balancing conservation efforts with sustainable use, ensuring the long-term health of these vital underwater ecosystems
Environmental impact of the 2025 Mw 6.5 Jan Mayen earthquake: A climate-change conditioned rock slope failure on Jan Mayen Island, Arctic Ocean
No full textHigh trophic plasticity in the mixotrophic Mastigias papua-Symbiodiniaceae holobiont: implications for the ecology of zooxanthellate jellyfishes
No full textThe trophic ecology of mixotrophic, zooxanthellate jellyfishes potentially spans a wide spectrum between autotrophy and heterotrophy. However, their degree of trophic plasticity along this spectrum is not well known. To better characterize their trophic ecology, we sampled the zooxanthellate medusa Mastigias papua in contrasting environments and sizes in Palau (Micronesia). We characterized their trophic ecology using isotopic (bulk δ13C and δ15N), elemental (C:N ratios), and fatty acid compositions. The different trophic indicators were correlated or anti-correlated as expected (Pearson’s correlation coefficient, rP > 0.5 or < -0.5 in 91.1% of cases, p < 0.05), indicating good agreement. The sampled M. papua were ordered in a trophic spectrum between autotrophy and heterotrophy (supported by decreasing δ13C, C:N, proportion of neutral lipid fatty acids (NLFA:TLFA), n-3:n-6 and increasing δ15N, eicosapentaenoic acid to docosahexaenoic acid ratio (EPA:DHA)). This trophic spectrum was mostly driven by sampling location with little influence of medusa size. Moreover, previous observations have shown that in a given location, the trophic ecology of M. papua can change over time. Thus, the positions on the trophic spectrum of the populations sampled here are not fixed, suggesting high trophic plasticity in M. papua. The heterotrophic end of the trophic spectrum was occupied by non-symbiotic M. papua, whereas the literature indicates that the autotrophic end of the spectrum corresponds to dominant autotrophy, where more than 100% of the carbon requirement is obtained by photosynthesis. Such high trophic plasticity has critical implications for the trophic ecology and blooming ability of zooxanthellate jellyfishe
Neodymium and Hafnium Isotope and Rare Earth Element Geochemical Cycling and Fluxes from the Amazon to the tropical western Atlantic
No full textContinental margins are a dynamic interface linking the terrestrial lithosphere and oceanic hydrosphere, thus controlling fluxes of terrigenous materials from land to ocean. In particular, estuaries are places channeling vast amounts of minerals, nutrients, organic matter and trace elements (TEs) in dissolved and particulate forms into the oceans. As many TEs are essential nutrients for phytoplankton growth, their concentrations ([TEs]) together with macronutrients in surface waters influence marine primary productivity, thereby impacting ocean ecosystems and carbon cycling. However, before entering the oceans, terrigenous TEs are modified at continental margins by various processes including removal, release and recycling. Consequently, studying geochemical cycling of TEs at continental margins is crucial for discerning their sources and processes that determine TE fluxes to oceans. Radiogenic neodymium (Nd) and hafnium (Hf) isotopic compositions, expressed as εNd and εHf, respectively are sensitive tracers of the origin and mixing of water masses and seawater-particle interactions at the continent-ocean interface. In this thesis a detailed investigation of the distributions of radiogenic Nd and Hf isotopes as well as rare earth elements and yttrium (REY) is performed across the Amazon freshwater plume, the Amazonian mangrove belt and the Amazon shelf and slope as part of the GEOTRACES GApr11 cruise. The objective is to investigate the sources and processes influencing the TE supplies, Nd and Hf isotope distributions and their fluxes to the western Atlantic Ocean