251 research outputs found
Warming by 1°C drives species and assemblage level responses in Antarcticaâs marine shallows
Forecasting assemblage-level responses to climate change remains one of the greatest challenges in global ecology [1
, 2
]. Data from the marine realm are limited because they largely come from experiments using limited numbers of species [3
], mesocosms whose interior conditions are unnatural [4
], and long-term correlation studies based on historical collections [5
]. We describe the first ever experiment to warm benthic assemblages to ecologically relevant levels in situ. Heated settlement panels were used to create three test conditions: ambient and 1°C and 2°C above ambient (predicted in the next 50 and 100 years, respectively [6]). We observed massive impacts on a marine assemblage, with near doubling of growth rates of Antarctic seabed life. Growth increases far exceed those expected from biological temperature relationships established more than 100 years ago by Arrhenius. These increases in growth resulted in a single âr-strategistâ pioneer species (the bryozoan Fenestrulina rugula) dominating seabed spatial cover and drove a reduction in overall diversity and evenness. In contrast, a 2°C rise produced divergent responses across species growth, resulting in higher variability in the assemblage. These data extend our ability to expand, integrate, and apply our knowledge of the impact of temperature on biological processes to predict organism, species, and ecosystem level ecological responses to regional warming
Extreme phenotypic plasticity in metabolic physiology of Antarctic demosponges
Seasonal measurements of the metabolic physiology of four Antarctic demosponges and their associated assemblages, maintained in a flow through aquarium facility, demonstrated one of the largest differences in seasonal strategies between species and their associated sponge communities. The sponge oxygen consumption measured here exhibited both the lowest and highest seasonal changes for any Antarctic species; metabolic rates varied from a 25% decrease to a 5.8 fold increase from winter to summer, a range which was greater than all 17 Antarctic marine species (encompassing eight phyla) previously investigated and amongst the highest recorded for any marine environment. The differences in nitrogen excretion, metabolic substrate utilization and tissue composition between species were, overall, greater than seasonal changes. The largest seasonal difference in tissue composition was an increase in CHN (Carbon, Hydrogen, and Nitrogen) content in Homaxinella balfourensis, a pioneer species in ice-scour regions, which changed growth form to a twig-like morph in winter. The considerable flexibility in seasonal and metabolic physiology across the Demospongiae likely enables these species to respond to rapid environmental change such as ice-scour, reductions in sea ice cover and ice-shelf collapse in the Polar Regions, shifting the paradigm that polar sponges always live âlife in the slow lane.â Great phenotypic plasticity in physiology has been linked to differences in symbiotic community composition, and this is likely to be a key factor in the global success of sponges in all marine environments and their dominant role in many climax communities
Jewels across the Landscape: Monitoring and Assessing the Quality of Lakes and Reservoirs in the United States
An early naturalist described lakes as âjewelsâ across the landscape and indeed they wereâŠat the end of the nineteenth century. As we settled the country and began to utilize the lake resource for our needs, things changed. Additionally, our needs for water brought about the construction of impoundments from ice ponds to small stock ponds up to mainstem impoundments along our major rivers. The lake resource in the United States now includes natural lakes in our northern tier of states, unique physiographic regions such as Florida and the Sand Hills of Nebraska, and the mountainous regions, and impoundments scattered across the entire landscape. In this chapter, we will describe efforts by an unique partnership between the individual states and tribal nations of the USA and the US Environmental Protection Agency to monitor and assess these systems. These efforts go beyond single water quality (chemistry) issues and include assessments targeting the goal of the Clean Water Act, namely, restoring, maintaining, and protecting the chemical, physical, and biological integrity of the nationâs lakes and reservoirs
Rivers and Streams: Upgrading Monitoring of the Nationâs Freshwater Resources - Meeting the Spirit of the Clean Water Act
The goal of the Clean Water Act (CWA) is to restore and maintain the chemical, physical and biological integrity of the waters in the United States. Much of the monitoring and assessment is reasonably delegated to the States to monitor and report the condition of their water to Congress through the Environmental Protection Agency. States have historically been fully occupied in monitoring the most egregious water quality problems along with select high priority water bodies. This approach, while addressing State priorities with finite resources, does not capture the full spectrum and scope of water quality conditions within and across State boundaries. Hence, the reporting on progress in meeting the goals of the CWA has not been realized. In this chapter, we describe the partnership between EPA, the States and Tribes to remedy this information gap for rivers and streams. Filling this gap requires both improved monitoring designs to reflect conditions across all waters as well as the expansion of indicators to move beyond water chemistry to include all three elements of the CWA goalâchemical, physical and biological integrity
Global hepatitis C elimination: an investment framework
WHO has set global targets for the elimination of hepatitis B and hepatitis C as a public health threat by 2030. However, investment in elimination programmes remains low. To help drive political commitment and catalyse domestic and international financing, we have developed a global investment framework for the elimination of hepatitis B and hepatitis C. The global investment framework presented in this Health Policy paper outlines national and international activities that will enable reductions in hepatitis C incidence and mortality, and identifies potential sources of funding and tools to help countries build the economic case for investing in national elimination activities. The goal of this framework is to provide a way for countries, particularly those with minimal resources, to gain the substantial economic benefit and cost savings that come from investing in hepatitis C elimination
Spatial and temporal dynamics of Antarctic shallow soft-bottom benthic communities: ecological drivers under climate change
Background: Marine soft sediments are some of the most widespread habitats in the ocean, playing a vital role in
global carbon cycling, but are amongst the least studied with regard to species composition and ecosystem functioning. This is particularly true of the Polar Regions, which are currently undergoing rapid climate change, the impacts
of which are poorly understood. Compared to other latitudes, Polar sediment habitats also experience additional
environmental drivers of strong seasonality and intense disturbance from iceberg scouring, which are major structural
forces for hard substratum communities. This study compared sediment assemblages from two coves, near Rothera
Point, Antarctic Peninsula, 67°S in order to understand the principal drivers of community structure, for the frst time,
evaluating composition across all size classes from mega- to micro-fauna.
Results: Morpho-taxonomy identifed 77 macrofaunal species with densities of 464â16,084 individuals mâ2
. eDNA
metabarcoding of microfauna, in summer only, identifed a higher diversity, 189 metazoan amplicon sequence variants (ASVs) using the 18S ribosomal RNA and 249 metazoan ASVs using the mitochondrial COI gene. Both techniques
recorded a greater taxonomic diversity in South Cove than Hangar Cove, with diferences in communities between
the coves, although the main taxonomic drivers varied between techniques. Morphotaxonomy identifed the main
diferences between coves as the mollusc, Altenaeum charcoti, the cnidarian Edwardsia sp. and the polychaetes from
the family cirratulidae. Metabarcoding identifed greater numbers of species of nematodes, crustaceans and Platyhelminthes in South Cove, but more bivalve species in Hangar Cove. There were no detectable diferences in community
composition, measured through morphotaxonomy, between seasons, years or due to iceberg disturbance.
Conclusions: This study found that unlike hard substratum communities the diversity of Antarctic soft sediment
communities is correlated with the same factors as other latitudes. Diversity was signifcantly correlated with grain
size and organic content, not iceberg scour. The increase in glacial sediment input as glaciers melt, may therefore be
more important than increased iceberg disturbance
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Continental-Scale Increase in Lake and Stream Phosphorus: Are Oligotrophic Systems Disappearing in the United States?
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.We describe continental-scale increases in lake and stream total phosphorus (TP) concentrations, identified through periodic probability surveys of thousands of water bodies in the conterminous U.S. The increases, observed over the period 2000â2014 were most notable in sites in relatively undisturbed catchments and where TP was initially low (e.g., less than 10 ÎŒg Lâ»Âč). Nationally, the percentage of stream length in the U.S. with TP †10 ÎŒg Lâ»Âč decreased from 24.5 to 10.4 to 1.6% from 2004 to 2009 to 2014; the percentage of lakes with TP †10 ÎŒg Lâ»Âč decreased from 24.9 to 6.7% between 2007 and 2012. Increasing TP concentrations appear to be ubiquitous, but their presence in undeveloped catchments suggests that they cannot be entirely attributed to either point or common non-point sources of TP
A horizon scan of global conservation issues for 2014
This paper presents the output of our fifth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity, but have yet to be widely considered. A team of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics which were identified via an iterative, Delphi-like process. The 15 topics include a carbon market induced financial crash, rapid geographic expansion of macroalgal cultivation, genetic control of invasive species, probiotic therapy for amphibians, and an emerging snake fungal disease. © 2013 Elsevier Ltd
A 2018 Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity.
This is our ninth annual horizon scan to identify emerging issues that we believe could affect global biological diversity, natural capital and ecosystem services, and conservation efforts. Our diverse and international team, with expertise in horizon scanning, science communication, as well as conservation science, practice, and policy, reviewed 117 potential issues. We identified the 15 that may have the greatest positive or negative effects but are not yet well recognised by the global conservation community. Themes among these topics include new mechanisms driving the emergence and geographic expansion of diseases, innovative biotechnologies, reassessments of global change, and the development of strategic infrastructure to facilitate global economic priorities
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Comment on Bachmann et al. (2013): A nonrepresentative sample cannot describe the extent of cultural eutrophication of natural lakes in the United States
In their recent paper, Bachmann et al. (2013) evaluate the extent to which natural lakes in the contiguous United States have been affected by cultural eutrophication since Europe-an settlement, using paleolimnological data collected during the 2007 National Lakes Assessment (NLA; U.S. Environ-mental Protection Agency [USEPA] 2009). The NLA sites were selected using a statistically valid sampling design that allows for the overall ecological condition of the nationâs lakes to be accurately characterized (USEPA 2009). Given the current consensus among limnologists regarding the prevalence of culturally eutrophic lakes (Finlayson and DâCruz 2005; Carpenter et al. 2011), the conclusion of Bachmann et al. that ââin the United States of America, the extent that natural lakes have been changed by cultural eutrophication does not seem to be largeââ (Bachmann et al. 2013, p. 950) is surprising. The findings of Bachmann et al. supporting this statement are not based on the entire NLA sample of natural lakes but rather on a subset of them. We demonstrate below that not only is this subset not representative of the entire population of natural lakes in the United States, but that it is biased toward lakes in regions with less anthropogenic activity and substantially lower nutrient concentrations. Consequently, we argue that the conclusions drawn by Bachmann et al. (2013) at the national scale are based upon a statistically flawed analysis
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