Research Highlights / Climate and Ecosystems
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September 10, 2013
Global-scale carbon and energy flows through the planktonic food web: an analysis with a coupled physical-biological model
Planktonic food web dynamics shape biogeochemical cycles and global patterns of ocean productivity across trophic levels. Primary production alone, for example, is a poor predictor of cross-ecosystem differences in fisheries yields. Predictive capability improves only after consideration of factors such as the number and efficiency of trophic links separating phytoplankton and fish. Limited representation and validation of planktonic food web dynamics within the present generation of Earth System Models limits both their resolution of biogeochemical processes and their utility for assessing climate impacts on living marine resources.
February 24, 2013
Heat stress reduces labor capacity under climate warming
The authors use existing occupational health and safety thresholds to establish a new metric to quantify a healthy, acclimated individual’s capacity to safely perform sustained labor under environmental heat stress (what we call labor capacity). Using climate model projections, we apply this metric to quantify the direct impact of global warming on the global human population in the future.
January 8, 2013
Cusk (Brosme brosme) and climate change: assessing the threat to a candidate marine fish species under the U.S. Endangered Species Act
This collaboration, led by NOAA and EPA scientists and entraining expertise from the University of Connecticut, evaluated the potential effects of climate change on cusk (Brosme brosme) in the Northwest Atlantic. Numbers of this demersal (bottom-dwelling) fish (Fig. 1) on the Northeast Atlantic continental shelf have declined dramatically over the past several decades. This is believed to be primarily a result of fishing activities. However, changes in the distribution and abundance of a number of marine fish stocks in the Northwest Atlantic have been linked to climate variability and change, suggesting that both fishing and climate may affect the future status of cusk.
August 10, 2012
Global calcite cycling constrained by sediment preservation controls
The primary objective of this work was to build a set of internally consistent and computationally efficient algorithms to represent the regionally varying production, water column dissolution, and sediment preservation of pelagic calcite, and analyze the biogeochemical implications.
July 1, 2012
Projected Response of an Endangered Marine Turtle Population to Climate Change
Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Marine turtles must lay eggs in sandy beaches and thus climate change can affect both their marine and terrestrial habitat. The population of critically endangered eastern Pacific leatherback turtles (Dermochelys coriacea) nesting on the northwest coast of Costa Rica has been studied in terms of its sensitivity to contemporary climate variability in the nesting beach and ocean.
May 18, 2012
An Integrated “End-To-End” Model For Climate-Fish Interactions
Climate impacts on marine ecosystems arise from a combination of direct influences of physical climate on organisms (e.g., temperature effects on metabolic process) and indirect effects controlled by interactions with directly affected organisms. Indirect influences may originate with primary producers (i.e., phytoplankton) and propagate upward from the bottom of the food web or with higher trophic levels (i.e., fish) and propagate downward. Elucidating and predicting the response of living marine resources to climate and fishing pressure thus requires movement toward models that resolve interactions spanning physics to fish in an integrated way.
April 6, 2012
An Overview of CMIP5 and the Experiment Design
The fifth phase of the Coupled Model Intercomparison Project (CMIP5) will produce a coordinated multi-model dataset that is designed to advance our knowledge of climate variability and climate change. Researchers worldwide will analyze the model output and produce results that will underlie the forthcoming IPCC Fifth Assessment Report. Unprecedented in scale, CMIP5 has attracted participation from all major climate modeling groups. Building on previous CMIP efforts, CMIP5 includes "long-term" simulations of 20th century climate and projections for the 21st century and beyond.
March 29, 2012
Reducing Uncertainty in Understanding Ocean Oxygen and Nitrogen Cycles
Oxygen minimum zones (OMZs) exclude many classes of the biological community and are major sites of fixed nitrogen removal from the open ocean. Previous estimates of rate of fixed nitrogen loss through denitrification in the pelagic ocean and in sediments have been unable to match estimates of the supply of fixed nitrogen via N2 fixation, rivers, and atmospheric deposition. This has led some scientists to the conclusion that the global ocean nitrogen cycle is out of balance, and the oceans are accumulating fixed nitrogen.
February 14, 2012
Will open ocean oxygen stress intensify under climate change?
Ten percent of today’s ocean volume is characterized by low level of dissolved oxygen similar to those found in the well-known "dead zones" in the Gulf of Mexico with 35% of global surface waters overlying at least some of this "hypoxia". Under global warming, higher temperatures would be expected to directly lower oxygen concentrations and enhanced stratification to reduce the flow of well-ventilated surface waters to the interior. Under such circumstances, it has been hypothesized that the open-ocean dead zones could greatly expand and indeed changes in low-oxygen waters have been invoked as evidence of climate change.
January 24, 2012
Pathways Between Primary Production and Fisheries Yields of Large Marine Ecosystems
There is considerable uncertainty in projections of the impact of climate on fisheries yields due to uncertainties in climate change impacts on primary production and the processes controlling how much primary production is transferred to fish. Primary production and proxies such as chlorophyll have proven to be useful predictors of fisheries yields at regional scales but show much less skill when applied globally. The marine food web dynamics that control the transfer of energy from phytoplankton to fish are complex and it has been postulated that the relationship between primary production and fisheries production may differ dramatically between ecosystems due to changes in planktonic foodweb structure.
July 3, 2011
Different magnitudes of projected subsurface ocean warming around Greenland and Antarctica
Recent acceleration of Greenland and Antarctic outlet glaciers and ice flows is closely linked to ocean warming, especially in the subsurface layer. This land ice melt will cause sea level rise.