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At least 415 records · Page 23Linked to original sources
USGS2000

Primary food resources in the Sacramento-San Joaquin Delta

The Sacramento-San Joaquin River Delta, a complex mosaic of tidal freshwater habitats, is now a focus of ecosystem rehabilitation because of changes in critical functions associated with its geographic location at the landestuary interface. One of these functions is the production, transport, and transformation of organic matter that constitutes the “primary food supply,” that is, the food supply to the base of the food web. Interest in the primary food supply is motivated by evidence for sub-optimal food quantity or quality at trophic levels that support fish recruitment, including primary consumers such as clams, mysids, cladocerans, rotifers, and native copepods. We used the historical data set to examine the magnitudes of the most important organic matter sources for the Delta, the factors underlying their interannual and longer-term variability, and the implications of ecosystem rehabilitation actions for these sources. Here, we present a summary of the first phase of the analysis, including the quantitative importance of different organic matter sources and some of the hydrological controls on their year-to-year variability. The full report of this first phaseincluding data sources, the methods of calculation, and references, is in press elsewhere (Jassby and Cloern forthcoming). The historical data analysis is part of a larger project in which measurements of stable isotopes and biogeochemical markers, and experiments on organic matter biodegradation and zooplankton growth rates, are being used collectively to define the primary food resources and their quality.

California↗
USGS2018

Indicators of ecosystem structure and function for the Upper Mississippi River System

This report documents the development of quantitative measures (indicators) of ecosystem structure and function for use in a Habitat Needs Assessment (HNA) for the Upper Mississippi River System (UMRS). HNAs are led periodically by the U.S. Army Corps of Engineers’ Upper Mississippi River Restoration (UMRR) Program, which is the primary habitat restoration program on the UMRS. The UMRR Program helps determine how Federal, State and nongovernmental agencies can best address environmental issues on one of the world’s largest and most diverse river systems. Each indicator in this report represents at least one management objective developed for the river system. These objectives were developed in a previous planning effort using an ecosystem management conceptual framework (USACE, 2011). The objectives represent five essential ecosystem characteristics: hydraulics and hydrology, biogeochemistry, geomorphology, habitat, and biota. Subsequent to the 2011 planning effort, the UMRR increased its focus on improving the health and resilience of the UMRS. The indicators presented here are based on the five essential ecosystem characteristics and four aspects of ecosystems thought to support general ecosystem resilience (the ability of an ecosystem to adapt and respond to disturbances): (1) connectivity, (2) diversity and redundancy, (3) controlling variables, and (4) slow processes. Thus, we developed indicators that quantify both essential ecosystem characteristics and characteristics of a resilient river system. The indicators documented in this report focus on important aspects of river floodplain hydrogeomorphology, given the fundamental role hydrogeomorphology plays in determining habitat conditions and ecosystem health and resilience at broad geographic scales. The information contained within this report provides a broader scale (for example, system-wide) context for management decisions made at finer scales (for example, within river reaches or at project sites) and is designed for use in the formal system-wide Habitat Needs Assessment II (HNA–II) led by the UMRR Program.

Upper Mississippi River System↗
USGS2016

Barriers to and opportunities for landward migration of coastal wetlands with sea-level rise

In the 21st century, accelerated sea-level rise and continued coastal development are expected to greatly alter coastal landscapes across the globe. Historically, many coastal ecosystems have responded to sea-level fluctuations via horizontal and vertical movement on the landscape. However, anthropogenic activities, including urbanization and the construction of flood-prevention infrastructure, can produce barriers that impede ecosystem migration. Here we show where tidal saline wetlands have the potential to migrate landward along the northern Gulf of Mexico coast, one of the most sea-level rise sensitive and wetland-rich regions of the world. Our findings can be used to identify migration corridors and develop sea-level rise adaptation strategies to help ensure the continued availability of wetland-associated ecosystem goods and services.

Alabama, Florida, Georgia, Louisiana, Mississippi,↗
USGS2010

Erosion and vegetation restoration impacts on ecosystem carbon dynamics in South China

To quantify the consequences of erosion and vegetation restoration on ecosystem C dynamics (a key element in understanding the terrestrial C cycle), field measurements were collected since 1959 at two experimental sites set up on highly disturbed barren land in South China. One site had received vegetation restoration (the restored site) while the other received no planting and remained barren (the barren site). The Erosion-Deposition Carbon Model (EDCM) was used to simulate the ecosystem C dynamics at both sites. The on-site observations in 2007 showed that soil organic C (SOC) storage in the top 80-cm soil layer at the barren site was 50.3 ± 3.5 Mg C ha −1 , half that of the restored site. The SOC and surface soil loss by erosion at the restored site from 1959 to 2007 was 3.7 Mg C ha −1 and 2.2 cm, respectively—one-third and one-eighth that of the barren site. The on-site C sequestration in SOC and vegetation at the restored site was 0.67 and 2.5 Mg C ha −1 yr −1 , respectively, from 1959 to 2007, driven largely by tree growth and high atmospheric N deposition in the study area. Simulated findings suggested that higher N deposition resulted in higher on-site SOC storage in the soil profile (with SOC in the top 20-cm layer increasing more significantly), and higher on-site ecosystem C sequestration as long as N saturation was not reached. Lacking human-induced vegetation recovery, the barren site remained as barren land from 1959 to 2007 and the on-site C decrease was 0.28 Mg C ha −1 yr −1 Our study clearly indicated that vegetation restoration and burial by soil erosion provide a large potential C sink in terrestrial ecosystems.

Soil Science Society of America Journal↗
USGS2004

Nitrogen fluxes and retention in urban watershed ecosystems

Although the watershed approach has long been used to study whole-ecosystem function, it has seldom been applied to study human-dominated systems, especially those dominated by urban and suburban land uses. Here we present 3 years of data on nitrogen (N) losses from one completely forested, one agricultural, and six urban/suburban watersheds, and input-output N budgets for suburban, forested, and agricultural watersheds. The work is a product of the Baltimore Ecosystem Study, a long-term study of urban and suburban ecosystems, and a component of the US National Science Foundation's long-term ecological research (LTER) network. As expected, urban and suburban watersheds had much higher N losses than did the completely forested watershed, with N yields ranging from 2.9 to 7.9 kg N ha −1 y −1 in the urban and suburban watersheds compared with less than 1 kg N ha −1 y −1 in the completely forested watershed. Yields from urban and suburban watersheds were lower than those from an agricultural watershed (13-19.8 kg N ha −1 y −1 ). Retention of N in the suburban watershed was surprisingly high, 75% of inputs, which were dominated by home lawn fertilizer (14.4 kg N ha −1 y −1 ) and atmospheric deposition (11.2 kg N ha −1 y −1 ). Detailed analysis of mechanisms of N retention, which must occur in the significant amounts of pervious surface present in urban and suburban watersheds, and which include storage in soils and vegetation and gaseous loss, is clearly warranted.

Maryland↗
USGS2013

Defining a data management strategy for USGS Chesapeake Bay studies

The mission of U.S. Geological Survey’s (USGS) Chesapeake Bay studies is to provide integrated science for improved understanding and management of the Chesapeake Bay ecosystem. Collective USGS efforts in the Chesapeake Bay watershed began in the 1980s, and by the mid-1990s the USGS adopted the watershed as one of its national place-based study areas. Great focus and effort by the USGS have been directed toward Chesapeake Bay studies for almost three decades. The USGS plays a key role in using “ecosystem-based adaptive management, which will provide science to improve the efficiency and accountability of Chesapeake Bay Program activities” (Phillips, 2011). Each year USGS Chesapeake Bay studies produce published research, monitoring data, and models addressing aspects of bay restoration such as, but not limited to, fish health, water quality, land-cover change, and habitat loss. The USGS is responsible for collaborating and sharing this information with other Federal agencies and partners as described under the President’s Executive Order 13508—Strategy for Protecting and Restoring the Chesapeake Bay Watershed signed by President Obama in 2009. Historically, the USGS Chesapeake Bay studies have relied on national USGS databases to store only major nationally available sources of data such as streamflow and water-quality data collected through local monitoring programs and projects, leaving a multitude of other important project data out of the data management process. This practice has led to inefficient methods of finding Chesapeake Bay studies data and underutilization of data resources. Data management by definition is “the business functions that develop and execute plans, policies, practices and projects that acquire, control, protect, deliver and enhance the value of data and information.” (Mosley, 2008a). In other words, data management is a way to preserve, integrate, and share data to address the needs of the Chesapeake Bay studies to better manage data resources, work more efficiently with partners, and facilitate holistic watershed science. It is now the goal of the USGS Chesapeake Bay studies to implement an enhanced and all-encompassing approach to data management. This report discusses preliminary efforts to implement a physical data management system for program data that is not replicated nationally through other USGS databases.

Chesapeake Bay↗
USGS2014

Extracellular enzyme kinetics scale with resource availability

Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent V max and apparent K m followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the K m of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales.

Biogeochemistry↗
USGS1987

Results of a workshop concerning assessment of the functions of bottomland hardwoods

The U.S. Environmental Protection Agency (EPA) is authorized under Section 404 of the Clean Water Act (33 U.S.C. 1344) to participate in the regulation of the discharge of dredged or fill material into waters of the United States. This regulatory authority is exercised in partnership with the U.S. Army Corps of Engineers, which has responsibility for permit issuance, and in consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service. Through amendments to the original statute, a series of legal actions and court decisions, and the development of operating guidance among the responsible agencies, Section 404 has evolved into the primary mechanism afforded Federal authorities for the protection of wetlands. EPA recognizes the importance of wetlands in achieving the goals of the Clean Water Act, which are to protect and maintain the chemical, physical, and biological integrity of the Nation’s waters. EPA Administrator Lee Thomas has identified wetlands protection as among the highest of Agency priorities. EPA recognizes that bottomland hardwood (BLH) wetlands have vital and unique attributes that, if lost, would severely impact the physical, chemical, and biological integrity of the Nation's waters. As part of a broad program to better protect the Nation's wetlands, EPA has therefore identified bottomland hardwood wetlands as a priority resource requiring special attention on a national basis. Recognizing the importance of implementing an effective, nationally consistent, and scientifically defensible regulatory program, EPA, in October 1984, issued Interim Operating Guidance to its field personnel for implementing the Section 404 regulatory program in bottomland hardwood wetlands. With the goal of improving and finalizing that guidance, EPA is sponsoring a series of workshops designed to answer key questions concerning BLH wetlands, based on the best scientific and technical information currently available. The first two workshops were directed toward summarizing existing scientific and technical knowledge concerning the functions of BLH ecosystems, the characteristics that are important to each function, and the impact of various development activities on those characteristics. The first workshop, which was held in St. Francisville, Louisiana, in December, 1984, examined a wetland zonation concept as a framework for gaining a greater understanding of BLH structure and function. The workshop set out to determine whether characterization of BLH resources as a series of relatively distinct zones, defined by concomitant variation in hydrologic regime, soils, and vegetation, might provide the basis for a useful and scientifically sound regulatory framework. For examp1e, if certain zones are of particular importance to one or more wetland functions that the Clean Water Act was intended to protect, then the zonation concept might be useful from the perspective of how various activities should be regulated. Discussions during the first workshop, however, indicated that the zonation concept provides, at best, only an incomplete picture of the structure and function of BLH ecosystems. In many cases, BLH functions are not limited to or closely correlated with particular zones and, furthermore, many factors other than zone are important determinants of BLH functions. With these responses in mind, the second workshop, held at Lake Lanier, Georgia, in July, 1985, was designed to elicit information on two questions. First, if zones are not an adequate framework for understanding the functions of BLH systems, what characteristics (predictors) can be used to assess the extent to which a particular site performs these functions? And second, what are the impacts of various development activities that often occur in BLH ecosystems on those characteristics and thus on the functions themselves? At the second workshop, individual workgroups dealing with particular subject areas (e.g., hydrology, water quality, fisheries, wildlife, ecosystem processes, and cultural/recreational/economic resources) were able to identify site characteristics that are important determinants of the performance of various functions. For example, the Hydrology Workgroup identified flood storage as one of three major hydrologic functions that BLH ecosystems perform. The workgroup then identified the most important characteristic (e.g., surface area of the site, soil saturation, and others) that determine flood storage and the likely impact of several common activities (e.g., conversion to soybean production and levee construction) on these characteristics. Some of the workgroups also provided estimates of the aggregate impact of activities, acting through all of the characteristics, on certain functions. The workgroups also identified key characteristics that could be used to identify high-value wetlands for various functions. In addition, the workgroups pointed out a number of topics needing further examination and discussion. First, all of the workgroups identified the need to develop the technical basis and information sources to address the problem of cumulative impacts in the regulatory process. Second, most of the workgroups noted the important of contextual variables in assessing the function of a particular site. For example, the location of a BLH site in relationship to other tracts of habitat is an important variable for many wildlife species. Similarly, the extent to which a site retains or transforms contaminants is depended not only on the characteristics of the site, but also on its position in a watershed relative to contaminant inputs. And finally, several of the workgroups pointed out that assessing the impact of an activity on a function is not as simple as "adding up" the impact on individual characteristics, but may depend instead on complex interactions among characteristics. Addressing these questions, as summarized in the objectives and discussions that follow, was the focus of the third workshop, the results of which are described in this report.

Report↗
USGS2001

Biodiversity losses: The downward spiral

The dramatic decline of whitebark pine ( Pinus albicaulis ) populations in the northwestern United States and southwestern Canada from the combined effects of fire exclusion, mountain pine beetles ( Dendroctonus ponderosae ), and white pine blister rust ( Cronartium ribicola ), and the projected decline of whitebark pine populations rangewide (Chapters 10 and 11) do not simply add up to local extirpations of a single tree species. Instead, the loss of whitebark pine has broad ecosystem-level consequences, eroding local plant and animal biodiversity, changing the time frame of succession, and altering the distribution of subalpine vegetation (Chapter 1). One potential casualty of this decline may be the midcontinental populations of the grizzly bear ( Ursus arctos horribilis ), which use whitebark pine seeds as a major food source (Chapter 7). Furthermore, whitebark pine is linked to other white pine ecosystems in the West through its seed-disperser, Clark's nutcracker ( Nucifraga columbiana ) (Chapter 5). Major declines in nutcracker populations ultimately seal the fate of several white pine ecosystems, and raise the question of whether restoration is possible once a certain threshold of decline is reached.

Book chapter↗
USGS2022

Greater sage-grouse respond positively to intensive post-fire restoration treatments

Habitat loss is the most prevalent threat to biodiversity in North America. One of the most threatened landscapes in the United States is the sagebrush ( Artemisia spp.) ecosystem, much of which has been fragmented or converted to non-native grasslands via the cheatgrass-fire cycle. Like many sagebrush obligates, greater sage-grouse ( Centrocercus urophasianus ) depend upon sagebrush for food and cover and are affected by changes to this ecosystem. We investigated habitat selection by 28 male greater sage-grouse during each of 3 years after a 113,000-ha wildfire in a sagebrush steppe ecosystem in Idaho and Oregon. During the study period, seeding and herbicide treatments were applied for habitat restoration. We evaluated sage-grouse responses to vegetation and post-fire restoration treatments. Throughout the 3 years post-fire, sage-grouse avoided areas with high exotic annual grass cover but selected strongly for recovering sagebrush and moderately strongly for perennial grasses. By the third year post-fire, they preferred high-density sagebrush, especially in winter when sagebrush is the primary component of the sage-grouse diet. Sage-grouse preferred forb habitat immediately post-fire, especially in summer, but this selection preference was less strong in later years. They also selected areas that were intensively treated with herbicide and seeded with sagebrush, grasses, and forbs, although these responses varied with time since treatment. Wildfire can have severe consequences for sagebrush-obligate species due to loss of large sagebrush plants used for food and for protection from predators and thermal extremes. Our results show that management efforts, including herbicide application and seeding of plants, directed at controlling exotic annual grasses after a wildfire can positively affect habitat selection by sage-grouse.

Ecology and Evolution↗
USGS2018

Desert wetlands record hydrologic variability within the Younger Dryas chronozone, Mojave Desert, USA

One of the enduring questions in the field of paleohydrology is how quickly desert wetland ecosystems responded to past episodes of abrupt climate change. Recent investigations in the Las Vegas Valley of southern Nevada have revealed that wetlands expanded and contracted on millennial and sub-millennial timescales in response to changes in climate during the late Quaternary. Here, we evaluate geologic evidence from multiple localities in the Mojave Desert and southern Great Basin that suggests the response of wetland systems to climate change is even faster, occurring at centennial, and possibly decadal, timescales. Paleowetland deposits at Dove Springs Wash, Mesquite Springs, and Little Dixie Wash, California, contain evidence of multiple wet and dry cycles in the form of organic-rich black mats, representing periods of past groundwater discharge and wet conditions, interbedded with colluvial, alluvial, and aeolian sediments, each representing dry conditions. Many of these wet-dry cycles date to within the Younger Dryas (YD) chronozone (12.9–11.7 ka), marking the first time intra -YD hydrologic variability has been documented in paleowetland deposits. Our results illustrate that desert wetland ecosystems are exceptionally sensitive to climate change and respond to climatic perturbations on timescales that are relevant to human society.

Arizona, California, Nevada↗
USGS2022

Vegetation type conversion in the US Southwest: Frontline observations and management responses

Forest and nonforest ecosystems of the western United States are experiencing major transformations in response to land-use change, climate warming, and their interactive effects with wildland fire. Some ecosystems are transitioning to persistent alternative types, hereafter called “vegetation type conversion” (VTC). VTC is one of the most pressing management issues in the southwestern US, yet current strategies to intervene and address change often use trial-and-error approaches devised after the fact. To better understand how to manage VTC, we gathered managers, scientists, and practitioners from across the southwestern US to collect their experiences with VTC challenges, management responses, and outcomes.

Arizona, California, Colorado, New Mexico↗
USGS2016

Scale-dependent habitat selection and size-based dominance in adult male American alligators

Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators ( Alligator mississippiensis ; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance and space use can provide great insight into their functional role in the ecosystem.

Mississippi↗
USGS2020

Estimating detection probability for Burmese Pythons with few detections and zero recapture events

Detection has been a long-standing challenge to monitoring populations of cryptic herpetofauna, which often have detection probabilities that are closer to zero than one. Burmese Pythons (Python bivittatus =Python molurus bivittatus), a recent invader in the Greater Everglades Ecosystem of Florida, are cryptic snakes that have long periods of inactivity. In addition, management actions such as removal of every python encountered create challenges for estimating population size and quantifying effects of management using traditional statistical approaches. We used Bayesian analysis of data collected from 59 visual surveys (144 person-surveys) covering a total distance of 485.6 km (1185.1 person-km) and radiotelemetry to estimate detection probability for Burmese Pythons, estimates which can improve interpretation of encounter and removal data. We found that detection probability ranged from 0.0001 0.0146 depending on whether or not efforts units accounted for total human effort across multiple surveyors and statistical method used. Based on our surveys, detection probabilities for Burmese Pythons are therefore likely < 0.05, but factors such as the number of searchers or time of day may improve detection probability. Traditional capture-recapture or visual surveys are, however, unlikely to yield accurate information on Burmese Python population size or trends across time without cost-prohibitive effort. Consequently, novel method development to monitor or measure Burmese Python populations, including techniques better equipped to handle very low detection, is critically needed for informative and reliable inferences about population size or the management effects of python removal.

Journal of Herpetology↗
USGS2014

Continuous resistivity profiling and seismic-reflection data collected in April 2010 from Indian River Bay, Delaware

A geophysical survey to delineate the fresh-saline groundwater interface and associated sub-bottom sedimentary structures beneath Indian River Bay, Delaware, was carried out in April 2010. This included surveying at higher spatial resolution in the vicinity of a study site at Holts Landing, where intensive onshore and offshore studies were subsequently completed. The total length of continuous resistivity profiling (CRP) survey lines was 145 kilometers (km), with 36 km of chirp seismic lines surveyed around the perimeter of the bay. Medium-resolution CRP surveying was performed using a 50-meter streamer in a baywide grid. Results of the surveying and data inversion showed the presence of many buried paleochannels beneath Indian River Bay that generally extended perpendicular from the shoreline in areas of modern tributaries, tidal creeks, and marshes. An especially wide and deep paleochannel system was imaged in the southeastern part of the bay near White Creek. Many paleochannels also had high-resistivity anomalies corresponding to low-salinity groundwater plumes associated with them, likely due to the presence of fine-grained estuarine mud and peats in the channel fills that act as submarine confining units. Where present, these units allow plumes of low-salinity groundwater that was recharged onshore to move beyond the shoreline, creating a complex fresh-saline groundwater interface in the subsurface. The properties of this interface are important considerations in construction of accurate coastal groundwater flow models. These models are required to help predict how nutrient-rich groundwater, recharged in agricultural watersheds such as this one, makes its way into coastal bays and impacts surface-water quality and estuarine ecosystems.

Delaware↗
USGS2013

A conceptual framework for Lake Michigan coastal/nearshore ecosystems, with application to Lake Michigan Lakewide Management Plan (LaMP) objectives

The Lakewide Management Plans (LaMPs) within the Great Lakes region are examples of broad-scale, collaborative resource-management efforts that require a sound ecosystems approach. Yet, the LaMP process is lacking a holistic framework that allows these individual actions to be planned and understood within the broader context of the Great Lakes ecosystem. In this paper we (1) introduce a conceptual framework that unifies ideas and language among Great Lakes managers and scientists, whose focus areas range from tributary watersheds to open-lake waters, and (2) illustrate how the framework can be used to outline the geomorphic, hydrologic biological, and societal processes that underlie several goals of the Lake Michigan LaMP, thus providing a holistic and fairly comprehensive roadmap for tackling these challenges. For each selected goal, we developed a matrix that identifies the key ecosystem processes within the cell for each lake zone and each discipline; we then provide one example where a process is poorly understood and a second where a process is understood, but its impact or importance is unclear. Implicit in these objectives was our intention to highlight the importance of the Great Lakes coastal/nearshore zone. Although the coastal/nearshore zone is the important linkage zone between the watershed and open-lake zones—and is the zone where most LaMP issues are focused--scientists and managers have a relatively poor understanding of how the coastal/nearshore zone functions. We envision follow-up steps including (1) collaborative development of a more detailed and more complete conceptual model of how (and where) identified processes are thought to function, and (2) a subsequent gap analysis of science and monitoring priorities.

Lake Michigan↗
USGS2024

Mechanisms by which marine heatwaves impact seabirds

Marine heatwaves (MHWs) are characterized by periods of extreme warming of local to basin-scale marine habitat. Effects of MHWs on some seabirds (e.g. mass die-offs) are well documented, but mechanisms by which seabirds respond to MHWs remain poorly understood. Following from a symposium at the 3 rd World Seabird Conference, this Theme Section presents recent research to address this knowledge gap. Studies included here spanned one or more MHW event, at spatial scales from individual seabird colonies to large marine ecosystems in subtropical, temperate, and polar oceans, and over timespans from months to decades. The findings summarized herein indicate that MHWs can affect seabirds directly by creating physiological heat stress that affects behavior or survival, or indirectly by disrupting seabird food webs, largely by altering metabolic rates in ectothermic prey species, leading to effects on their associated predators and prey. Four main mechanisms by which MHWs affect seabirds are (1) habitat modification, (2) physiological forcing, (3) behavioral responses, and (4) ecological processes or species interactions. Most seabird species have experienced limited effects from MHWs to date, owing to ecological and behavioral adaptations that buffer MHW effects. However, the intensity and frequency of MHWs is increasing due to global warming, and more seabird species may have difficulty coping with future heatwave events. Also, MHW impacts can persist for years after a MHW ends, so consequences of recent or future MHWs could continue to unfold over time for many long-lived seabird species.

MEPS↗
USGS2005

Coral disease and health workshop: Coral histopathology II, July 12-14, 2005

The health and continued existence of coral reef ecosystems are threatened by an increasing array of environmental and anthropogenic impacts. Coral disease is one of the prominent causes of increased mortality among reefs globally, particularly in the Caribbean. Although over 40 different coral diseases and syndromes have been reported worldwide, only a few etiological agents have been confirmed; most pathogens remain unknown and the dynamics of disease transmission, pathogenicity and mortality are not understood. Causal relationships have been documented for only a few of the coral diseases, while new syndromes continue to emerge. Extensive field observations by coral biologists have provided substantial documentation of a plethora of new pathologies, but our understanding, however, has been limited to descriptions of gross lesions with names reflecting these observations (e.g., black band, white band, dark spot). To determine etiology, we must equip coral diseases scientists with basic biomedical knowledge and specialized training in areas such as histology, cell biology and pathology. Only through combining descriptive science with mechanistic science and employing the synthesis epizootiology provides will we be able to gain insight into causation and become equipped to handle the pending crisis. One of the critical challenges faced by coral disease researchers is to establish a framework to systematically study coral pathologies drawing from the field of diagnostic medicine and pathology and using generally accepted nomenclature. This process began in April 2004, with a workshop titled Coral Disease and Health Workshop: Developing Diagnostic Criteria co-convened by the Coral Disease and Health Consortium (CDHC), a working group organized under the auspices of the U.S. Coral Reef Task Force, and the International Registry for Coral Pathology (IRCP). The workshop was hosted by the U.S. Geological Survey, National Wildlife Health Center (NWHC) in Madison, Wisconsin and was focused on gross morphology and disease signs observed in the field. A resounding recommendation from the histopathologists participating in the workshop was the urgent need to develop diagnostic criteria that are suitable to move from gross observations to morphological diagnoses based on evaluation of microscopic anatomy. As a continuation of building the foundation and framework for coral disease diagnostics, the CDHC convened the Coral Disease and Health Workshop: Coral Histopathology II in Charleston, South Carolina, July 11-14, 2005. The workshop was hosted by the Department of Pathology and Laboratory Medicine at the Medical University of South Carolina, Charleston, SC which provided expertise, facilities and equipment in support of the workshop. All of the histological slides and related photographs used in the discussions were prepared and supplied by the IRCP. This workshop brought together 15 experts in veterinary and medical pathology and coral biology from national and international research institutes and government laboratories. The mission was to devise a standardized approach to examining microscopic anatomy and pathology of corals and a standardized nomenclature to facilitate accurate descriptions of the microscopic morphology of corals and enhance communication among specialists investigating causes of coral death. 2 The participants of this workshop deliberated for 3 days to refine the nomenclature for gross and microscopic anatomy of corals and systematically described microscopic changes associated with selected coral diseases. The findings and recommendations from the deliberations will be submitted to the research community for peer review. The standardized nomenclature and descriptions produced at this workshop will ultimately be made available to the scientific community through a variety of media including the World Wide Web. An exciting highlight of this meeting was provided by Professor Robert Ogilvie (MUSC Department of Cell Biology and Anatomy) when he introduced participants to a new digital technology that is revolutionizing histology and histopathology in the medical field. The Virtual Slide technology creates digital images of histological tissue sections by computer scanning actual slides in high definition and storing the images for retrieval and viewing. Virtual slides now allow any investigator with access to a computer and the web to view, search, annotate and comment on the same tissue sections in real time. Medical and veterinary slide libraries across the country are being converted into virtual slides to enhance biomedical education, research and diagnosis. The coral health and disease researchers at this workshop deem virtual slides as a significant way to increase capabilities in coral histology and a means for pathology consultations on coral disease cases on a global scale.

NOAA Technical Memorandum↗