Warm-water coral reefs and climate change Spalding, Mark D.; Brown, Barbara E.
Science (American Association for the Advancement of Science),
11/2015, Letnik:
350, Številka:
6262
Journal Article
Recenzirano
Coral reefs are highly dynamic ecosystems that are regularly exposed to natural perturbations. Human activities have increased the range, intensity, and frequency of disturbance to reefs. Threats ...such as overfishing and pollution are being compounded by climate change, notably warming and ocean acidification. Elevated temperatures are driving increasingly frequent bleaching events that can lead to the loss of both coral cover and reef structural complexity. There remains considerable variability in the distribution of threats and in the ability of reefs to survive or recover from such disturbances. Without significant emissions reductions, however, the future of coral reefs is increasingly bleak.
Although invasive species are widely recognized as a major threat to marine biodiversity, there has been no quantitative global assessment of their impacts and routes of introduction. Here, we report ...initial results from the first such global assessment. Drawing from over 350 databases and other sources, we synthesized information on 329 marine invasive species, including their distribution, impacts on biodiversity, and introduction pathways. Initial analyses show that only 16% of marine ecoregions have no reported marine invasions, and even that figure may be inflated due to underâreporting. International shipping, followed by aquaculture, represent the major means of introduction. Our geographically referenced and publicly available database provides a framework that can be used to highlight the invasive taxa that are most threatening, as well as to prioritize the invasion pathways that pose the greatest threat.
The conservation and sustainable use of marine resources is a highlighted goal on a growing number of national and international policy agendas. Unfortunately, efforts to assess progress, as well as ...to strategically plan and prioritize new marine conservation measures, have been hampered by the lack of a detailed, comprehensive biogeographic system to classify the oceans. Here we report on a new global system for coastal and shelf areas: the Marine Ecoregions of the World, or MEOW, a nested system of 12 realms, 62 provinces, and 232 ecoregions. This system provides considerably better spatial resolution than earlier global systems, yet it preserves many common elements and can be cross-referenced to many regional biogeographic classifications. The designation of terrestrial ecoregions has revolutionized priority setting and planning for terrestrial conservation; we anticipate similar benefits from the use of a coherent and credible marine system.
The oyster habitat in the USA is a valuable resource that has suffered significant declines over the past century. While this loss of habitat is well documented, the loss of associated ecosystem ...services remains poorly quantified. Meanwhile, ecosystem service recovery has become a major impetus for restoration. Here we propose a model for estimating the volume of water filtered by oyster populations under field conditions and make estimates of the contribution of past (c. 1880–1910) and present (c. 2000–2010) oyster populations to improving water quality in 13 US estuaries. We find that filtration capacity of oysters has declined almost universally (12 of the 13 estuaries examined) by a median of 85 %. Whereas historically, oyster populations achieved full estuary filtration (filtering a volume equivalent or larger than the entire estuary volume within the residence time of the water) in six of the eight estuaries in the Gulf of Mexico during summer months, this is now the case for only one estuary: Apalachicola Bay, Florida. By contrast, while all five estuaries on the North Atlantic coast showed large decreases in filtration capacity, none were achieving full estuary filtration at the time of our c. 1900 historic baseline. This apparent difference from the Gulf of Mexico is explained at least in part by our North Atlantic baseline representing a shifted baseline, as surveyed populations were already much reduced by exploitation in this region.
Coastal ecosystems, particularly intertidal wetlands and reefs (coral and shellfish), can play a critical role in reducing the vulnerability of coastal communities to rising seas and coastal hazards, ...through their multiple roles in wave attenuation, sediment capture, vertical accretion, erosion reduction and the mitigation of storm surge and debris movement. There is growing understanding of the array of factors that affect the strength or efficacy of these ecosystem services in different locations, as well as management interventions which may restore or enhance such values. Improved understanding and application of such knowledge will form a critical part of coastal adaptation planning, likely reducing the need for expensive engineering options in some locations, and providing a complementary tool in hybrid engineering design. Irrespective of future climate change, coastal hazards already impact countless communities and the appropriate use of ecosystem-based adaptation strategies offers a valuable and effective tool for present-day management. Maintaining and enhancing coastal systems will also support the continued provision of other coastal services, including the provision of food and maintenance of coastal resource dependent livelihoods.
•Coastal communities are vulnerable to coastal hazards and impacts of climate change.•Reviews show intertidal wetlands and reefs protect coasts in a variety of ways.•Drivers of variance in protection levels can be identified from existing research.•Coastal ecosystems can provide effective tools for coastal protection and adaptation.
We present the results of our 13th annual horizon scan of issues likely to impact on biodiversity conservation. Issues are either novel within the biological conservation sector or could cause a ...substantial step-change in impact, either globally or regionally. Our global panel of 26 scientists and practitioners identified 15 issues that we believe to represent the highest priorities for tracking and action. Many of the issues we identified, including the impact of satellite megaconstellations and the use of long-distance wireless energy transfer, have both elements of threats and emerging opportunities. A recent state-sponsored application to commence deep-sea mining represents a significant step-change in impact. We hope that this horizon scan will increase research and policy attention on the highlighted issues.
Our 13th annual horizon scan identified 15 emerging issues of concern for global biodiversity conservation.A panel of 26 scientists and practitioners submitted a total of 80 topics that were ranked using a Delphi-style technique according to the novelty and likelihood of impact on biodiversity conservation.The top 36 issues were discussed at an online meeting held in September 2021 during which issues were ranked according to the same criteria.Our 15 issues cover impacts ranging from satellite megaconstellations to deep-sea mining.Other emerging issues include floating photovoltaics, long-distance wireless energy, and ammonia as a fuel source.
We present the results of our eighth annual horizon scan of emerging issues likely to affect global biological diversity, the environment, and conservation efforts in the future. The potential ...effects of these novel issues might not yet be fully recognized or understood by the global conservation community, and the issues can be regarded as both opportunities and risks. A diverse international team with collective expertise in horizon scanning, science communication, and conservation research, practice, and policy reviewed 100 potential issues and identified 15 that qualified as emerging, with potential substantial global effects. These issues include new developments in energy storage and fuel production, sand extraction, potential solutions to combat coral bleaching and invasive marine species, and blockchain technology.
This is the eighth such annual horizon scan.
An international team with expertise in horizon scanning, science communication, and conservation research, practice, and policy identified 15 issues, following widespread consultation and a Delphi-like scoring process to identify the most important.
The issues were wide ranging, and include sand extraction, blockchain technology, use of robotics to combat invasive species, and new developments in energy storage and fuel production.
Off-shelf waters cover 66% of the planet. Growing concerns about the state of natural resources in these waters, and of future threats have led to a growing movement to improve management and ...conservation of natural resources. However, efforts to assess progress and to further plan and prioritise management interventions have been held back in part by the lack of a comprehensive biogeographic classification for the high seas. In this work we review existing efforts at classifying the surface pelagic waters of the world’s oceans and we present a synthesis classification which draws both on known taxonomic biogeography and on the oceanographic forces which are major drivers of ecological patterns. We describe a nested system of 37 pelagic provinces of the world, nested into a system of four broad realms. Ecologically we have also differentiated a system of 7 biomes which are spatially disjoint but united by common abiotic conditions creating physiognomically similar communities. This system builds on existing work and is further intended to align closely with the coastal biogeographic regionalisation provided by the Marine Ecoregions of the World classification. It is hoped that it will provide a valuable tool in supporting threat analysis, priority setting, policy development and active management of the world’s pelagic oceans.
► We review past biogeographic classifications of the pelagic ecosystems of the world’s oceans. ► We develop a synthesis that considers taxonomic biogeography and oceanographic processes. ► The proposed system has 37 pelagic provinces in 4 broad oceanic realms. ► It also has 7 geographically disjoint biomes that have physiognomically similar communities.
This paper describes how the initial melt generation physics with differing pressure generation dynamics lead to either conventional melting or one dimensional (1D) melting. An historic review of the ...development of single screw melting models is presented. First, a review of the classic model is briefly presented. Second, after an analysis of literature melting data developed using the Maddock solidification procedure, a screw rotation concept melting model is presented that correlates very well with the melting analysis. Third, a new 1D film melting model is developed to analyze melting when the melt film does not encapsulate the solid bed. This physical model provides for the first time a quantitative model for the initiation and ultimate solid bed melting of the 1D melting process. Finally, a new concept and resulting model demonstrate that Reynold's barring concept for pressure generation in the initial melt film at the barrel interface may provide the mechanism that relates to whether the solid bed is or is not encapsulated.
Single Screw Delay Zone Melt Dynamics
The conservation of coastal ecosystems can provide considerable coastal protection benefits, but this role has not been sufficiently accounted for in coastal planning and engineering. Substantial ...evidence now exists showing how, and under what conditions, ecosystems can play a valuable function in wave and storm surge attenuation, erosion reduction, and in the longer term maintenance of the coastal profile. Both through their capacity for self repair and recovery, and through the often considerable cobenefits they provide, ecosystems can offer notable advantages over traditional engineering approaches in some settings. They can also be combined in “hybrid” engineering designs. We make 10 recommendations to encourage the utilization of existing knowledge and to improve the incorporation of ecosystems into policy, planning and funding for coastal hazard risk reduction.
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