1,721,248 research outputs found
Deep-ocean climate change impacts on habitats, fish and fisheries
No full textThis publication presents the outcome of a meeting between the FAO/UNEP ABNJ Deep-seas and Biodiversity project and the Deep Ocean Stewardship Initiative. Itfocuses on the impacts of climatic changes on demersal fisheries, and the interactions of these fisheries with other species and vulnerable marine ecosystems. Regional fisheries management organizations rely on scientific information to develop advice to managers. In recent decades, climate change has been a focus largely as a unidirectional forcing over decadal timescales. However, changes can occur abruptly when critical thresholds are crossed. Moreover, distribution changes are expected as populations shift from existing to new areas. Hence, there is a need for new monitoring programmes to help scientists understand how these changes affect productivity and biodiversity. The principal cause of climate change is rising greenhouse gases and other compounds in the atmosphere that trap heat causing global warming, leading to deoxygenation and acidification in the oceans. Three-dimensional fully coupled earth system models are used to predict the extent of these changes in the deep oceans at 200–2500 m depth. Trends in changes are identified in many variables, including temperature, pH, oxygen and supply of particulate organic carbon (POC). Regional differences are identified, indicating the complexity of the predictions. The response of various fish and invertebrate species to these changes in the physical environment are analysed using hazard and suitability modelling. Predictions are made to changes in distributions of commercial species, though in practice the processes governing population abundance are poorly understood in the deep-sea environment, and predicte
Deep-sea fundamentals
No full textMarine areas beyond national jurisdiction (ABNJ) are almost entirely comprised of deep ocean, which harbor a significant portion of global biodiversity. The little that we know of the deep sea has revealed a remarkable suite of habitats that provide the planet and its inhabitants with crucial ecosystem services. A precautionary and ecosystem-based management approach is necessary to ensure the conservation and sustainable use of biodiversity in ABNJ. For this to occur, continued international cooperation is needed to advance scientific investigation
Incorporating deep-ocean biodiversity into climate change policy - policy brief
No full textKey Messages: ● Deep-ocean biodiversity underpins climate stability bysequestering carbon and regulating the global carbon cycle.● Human disturbance of deep-ocean biodiversity diminishesthe ocean’s capacity to remove carbon from the atmosphere.● It is essential to incorporate protection of deep-oceanbiodiversity into UNFCCC policy. <br/
Redefining the Influence of Chemosynthetic Ecosystems for Effective Management
No full textKey Messages:1. Chemosynthetic ecosystems can influence the function and health of our ocean.2. It is necessary to broaden the definition of chemosynthetic ecosystems (hydrothermalvents and hydrocarbon seeps) to include their zone of influence and expand perceptionof these systems as broad habitat areas rather than isolated islands in the deep sea.3. Chemosynthetic ecosystems can be impacted by deep-water fishing, offshore oil and gasextraction, and deep-sea mining.4. Standardized methodological approaches for baseline surveys, monito
Stable isotope signatures and methane use by New Zealand cold seep benthos
No full textThe carbon isotopic composition of seep faunal tissue represents a time-integrated view of the interaction between biology and the biogeochemical gradients within the environment. Here we provide an initial description of carbon and nitrogen stable isotope signatures of dominant symbiont-bearing megafauna and heterotrophic mega- and macrofauna from 10 methane-seep sites on the continental margin of the North Island of New Zealand (662–1201 m water depth). Isotopic signatures suggest that sulfide oxidation supports symbiont-bearing taxa including solemyid and vesicomyid bivalves, and methanotrophic symbionts are present in the seep mussel Bathymodiolus sp. Multiple species of Frenulata (Siboglinidae) are present and have a range of isotopic values that are indicative of both thiotroph- and methanotroph-based nutrition. Isotopic composition of the tubeworm Lamellibrachia sp. varied by 23.3‰ among individuals although there was no consistent difference among sites. Variation in methane use by heterotrophic fauna appears to reflect the availability of hard vs. soft substrate; macrofauna on hard substrates had high ?13C signatures, reflecting consumption of photosynthetic-derived organic matter. Two unique, biotic assemblages were discovered to be fueled largely by methane: a hard-substrate, multi-phyla sponge-associated community (inhabiting the sponge Pseudosuberites sp.) and a soft-sediment assemblage dominated by ampharetid polychaetes. Isotope signatures yield estimates of 38–100% and 6–100% methane-derived carbon in sponge associates and ampharetid-bed macrofauna, respectively. These estimates are comparable to those made for deeper methane seeps at the Florida Escarpment (3290 m) and Kodiak, Alaska seeps (4445 m). The overall high use of methane as a carbon source by both symbiont-bearing and heterotrophic fauna suggests that New Zealand methane seeps are an ideal model system to study the interaction among metazoans, bacteria, archaea, and their resulting effect on methane cycles
Microbes as marine habitat formers and ecosystem engineers
No full textDespite their small individual size, marine prokaryotic and eukaryotic microbes can form large 3D structures and complex habitats. These habitats contribute to seafloor heterogeneity, facilitating colonization by animals and protists. They also provide food and refuge for a variety of species and promote novel ecological interactions. Here we illustrate the role of microbes as ecosystem engineers and propose a classification based on five types of habitat: microbial mats, microbial forests, microbial-mineralized habitats, microbial outcrops and microbial nodules. We also describe the metabolic processes of microbial habitat formers and their ecological roles, highlighting current gaps in knowledge. Their biogeography indicates that these habitats are widespread in all oceans and are continuously being discovered across latitudes and depths. These habitats are also expected to expand under future global change owing to their ability to exploit extreme environmental conditions. Given their high ecological relevance and their role in supporting endemic species and high biodiversity levels, microbial habitats should be included in future spatial planning, conservation and management measures
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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