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Geology report for proposed oil and gas lease sale No. 90; continental margin off the southeastern United States

This report summarizes our general knowledge of the geology and petroleum potential, as well as potential problems and hazards associated with development of petroleum resources, within the area proposed for nominations for lease sale number 90. This area includes the U.S. eastern continental margin from Raleigh Bay, just south of Cape Hatteras, to southern Florida, including the upper Continental Slope and inner Blake Plateau. The area for possible sales for lease sale number 90, as well as the area for lease sale number 78 and the previous areas leased are shown in figure 1; physiographic features of the region are shown in figure 2. Six exploration wells have been drilled within the proposed lease area (figs. 3 and 4), but no commercial discoveries have been made. All six wells were drilled on the Continental Shelf. No commercial production has been obtained onshore in the region. The areas already drilled have thin sedimentary rock sections, and the deeper strata are dominantly of continental facies. Petroleum formation may have been hindered by a lack of organic material and lack of sufficient burial for thermal maturation. However, analyses of drilling and seismic profiling data presented here indicate that a much thicker section of sedimentary rocks containing a much higher proportion of marine deposits, exists seaward of the Continental Shelf. These geologic conditions imply that the basins farther offshore may be more favorable environments for generating petroleum.

Open-File Report↗

Vision for a worldwide fluvial-sediment information network

The nations of the world suffer both from the deleterious effects of some natural and human-altered fluxes of fluvial sediment and a lack of consistent and reliable information on the temporal and spatial occurrence of fluvial sediments. Decades ago, this difficulty was unavoidable due to a lack of understanding of the magnitude and scope of environmental influences exerted by fluvial sediment coupled with a dearth of tools for monitoring and studying the data. Such is no longer the case. Fluvial sediment has a broad influence on the environment and humanity. Data needs that were once limited primarily to reservoir and channel maintenance now include issues associated with public water supply; contaminated sediment management; productivity of agricultural lands; stream restoration and watershed health; in-stream biotic stability; post-wildfire channel morphology; dam decommissioning, rehabilitation, or removal; and legal requirements for sediment management (Gray and Glysson, 2005). The adverse effects of poorly managed or unmanaged sediment movement related to these and other issues are well-known qualitatively, and in some cases quantitatively. For example, physical, chemical, and biological damages attributable to fluvial sediment in North America alone are now estimated to range between $20 billion and $50 billion annually (Pimental and others, 1995; Osterkamp and others, 1998; 2004). Capabilities for monitoring, analyzing, storing, and sharing fluvial-sediment data have been developed and, in many cases, are sufficiently mature for consideration for global utilization. Hence, there is not only a strong and expanding need for a global effort to gauge and understand fluvial-sediment characteristics and processes better, but the knowledge and tools to achieve these ends are largely available and ready for their applicability to be evaluated. Given the increasing importance of erosion and sediment processes for water-resources management, an International Sedimentation Initiative (ISI, 2007a), under the United Nations Educational, Scientific, and Cultural Organization’s International Hydrologic Programme (IHP, 2007) was adopted in 2004. The ISI, the focus of which is on sustainable water-resources management on the global scale, features six major activities and projects, which are listed as part of the section entitled, “Relation of the WoFSIN concept to the thrusts of the International Sedimentation Initiative,” that precedes the “Conclusions” section of this paper. Based on the need for more, and more consistent and reliable fluvial-sediment information and on the existence of the ISI and other international and national sediment programs, we envision the need for a Worldwide Fluvial Sediment-Information Network (WoFSIN) with a focus on data acquisition, storage, and dissemination globally. Envisioned components of a WoFSIN, administered largely via the Internet and relying mostly on the benefits derived from existing resources and programs, follow that summary. The goal of the WoFSIN is to maximize the availability and usefulness of the world’s historical and current fluvial-sediment and ancillary data through collaboration with existing programs so as to require few additional resources in the long-term. Thus, the WoFSIN concept was developed recognizing that informed resource management is predicated on the availability of adequate and reliable information. The WoFSIN is described in the ensuing sections in stand-alone fashion, followed by a section that describes the complementary aspects of the WoFSIN and the International Sediment Initiative. Thus, our first objective is to describe the fundamental components of a WoFSIN. Our second objective is to identify overlap or gaps between the WoFSIN and ISI concepts that might be useful in refining the ISI’s ability to meet its global mission to develop decision support for sediment management at the global scale more fully, cost-effectively, and (or) with enhanced quality.

Conference Paper↗

Toward a shared vision for climate-informed resource stewardship

Climate-change adaptation planning processes and tools are increasing in number and evolving rapidly. During times of innovation and proliferation, a potential danger is incoherence, when well-intended contributions can overwhelm, create confusion, or mask complementarities. A shared vision is needed to avoid duplication, reduce misunderstandings, and facilitate work across jurisdictions to steward resources undergoing profound changes. Such a vision would document fundamental tools and approaches while allowing flexibility to match highly varied management contexts and organizational missions. Fortunately, the preconditions for coherence exist. Here, we illustrate how climate-change adaptation tools—including scenario planning, conceptual frameworks, structured decision making, and impact-evaluation methods—can be (and are) used in tandem to support adaptation planning that accounts for uncertainty, considers a broad range of strategies and actions, makes transparent and robust choices, evaluates outcomes, and is flexible and responsive to the decision context.

Frontiers in Ecology and the Environment↗

Balancing lake ecological condition and agriculture irrigation needs in the Mississippi Alluvial Valley

The Mississippi Alluvial Valley includes hundreds of floodplain lakes that support unique fish assemblages and high biodiversity. Irrigation practices in the valley have lowered the water table , increasing the cost of pumping water, and necessitating the use of floodplain lakes as a source of water for irrigation. This development has prompted the need to regulate water withdrawals to protect aquatic resources, but it is unknown how much water can be withdrawn from lakes before ecological integrity is compromised. To estimate withdrawal limits, we examined descriptors of lake water quality (i.e., total nitrogen, total phosphorus, turbidity, Secchi visibility, chlorophyll- a ) and fish assemblages (species richness, diversity, composition) relative to maximum depth in 59 floodplain lakes. Change-point regression analysis was applied to identify critical depths at which the relationships between depth and lake descriptors exhibited a rapid shift in slope, suggesting possible thresholds. All our water quality and fish assemblage descriptors showed rapid changes relative to depth near 1.2–2.0 m maximum depth. This threshold span may help inform regulatory decisions about water withdrawal limits. Alternatives to explain the triggers of the observed threshold span are considered.

Arkansas, Mississippi↗

Mean annual streamflow of selected drainage basins in the coal area of southeastern Montana

Streamflow characteristics of drainage basins within the Fort Union coal region of southeastern Montana were estimated to provide premining data for evaluating the future effects of mining on the environment. Estimated annual mean streamflow at 22 data-collection stations for water years 1975-77 ranged from 0 to 887 cubic feet per second. These estimates are based on miscellaneous-streamflow records at each station and continuous-streamflow records from other stations in the study area. Estimated mean annual streamflow for a 10-year period (water years 1968- 77) ranged from 0 to 572 cubic feet per second. These long-term estimates were based on data from stations near the study area having continuous- streamflow records. Estimated mean annual runoff in inches for selected drainage basins within the study area showed no discernible pattern. Many of the drainage basins had a mean annual runoff of less than 0.60 inch; the maximum observed mean annual runoff was 4.45 inches.

Montana↗

Evaluation of coal-mining impacts using numerical classification of benthic invertebrate data from streams draining a heavily mined basin in eastern Tennessee

Coal-mining impacts on Smoky Creek, eastern Tennessee were evaluated using water quality and benthic invertebrate data. Data from mined sites were also compared with water quality and invertebrate fauna found at Crabapple Branch, an undisturbed stream in a nearby basin. Although differences in water quality constituent concentrations and physical habitat conditions at sampling sites were apparent, commonly used measures of benthic invertebrate sample data such as number of taxa, sample diversity, number of organisms, and biomass were inadequate for determining differences in stream environments. Clustering algorithms were more useful in determining differences in benthic invertebrate community structure and composition. Normal (collections) and inverse (species) analyses based on presence-absence data of species of Ephemeroptera, Plecoptera, and Tricoptera were compared using constancy, fidelity, and relative abundance of species found at stations with similar fauna. These analyses identified differences in benthic community composition due to seasonal variations in invertebrate life histories. When data from a single season were examined, sites on tributary streams generally clustered separately from sites on Smoky Creek. These analyses compared with differences in water quality, stream size, and substrate characteristics between tributary sites and the more degraded main stem sites, indicated that numerical classification of invertebrate data can provide discharge-independent information useful in rapid evaluations of in-stream environmental conditions.

Tennessee↗

Evolution and preservation potential of fluvial and transgressive deposits on the Louisiana inner shelf: Understanding depositional processes to support coastal management

The barrier-island systems of the Mississippi River Delta plain are currently undergoing some of the highest rates of shoreline retreat in North America (~20 m/year). Effective management of this coastal area requires an understanding of the processes involved in shoreline erosion and measures that can be enacted to reduce loss. The dominant stratigraphy of the delta plain is fluvial mud (silts and clays), delivered in suspension via a series of shallow-water delta lobes that prograded across the shelf throughout the Holocene. Abandonment of a delta lobe through avulsion leads to rapid land subsidence through compaction within the muddy framework. As the deltaic headland subsides below sea level, the marine environment transgresses the bays and wetlands, reworking the available sands into transgressive barrier shorelines. This natural process is further complicated by numerous factors: (1) global sea-level rise; (2) reduced sediment load within the Mississippi River; (3) diversion of the sediment load away from the barrier shorelines to the deep shelf; (4) storm-induced erosion; and (5) human alteration of the littoral process through the construction of hardened shorelines, canals, and other activities. This suite of factors has led to the deterioration of the barrier-island systems that protect interior wetlands and human infrastructure from normal wave activity and periodic storm impact. Interior wetland loss results in an increased tidal prism and inlet cross-sectional areas, and expanding ebb-tidal deltas, which removes sand from the littoral processes through diversion and sequestration. Shoreface erosion of the deltaic headlands does not provide sufficient sand to balance the loss, resulting in thinning and dislocation of the islands. Abatement measures include replenishing lost sediment with similar material, excavated from discrete sandy deposits within the muddy delta plain. These sand bodies were deposited by the same cyclical processes that formed the barrier islands, and understanding these processes is necessary to characterize their location, extent, and resource potential. In this paper we demonstrate the dominant fluvial and marine-transgressive depositional processes that occur on the inner shelf, and identify the preservation and resource potential of fluvio-deltaic deposits for coastal management in Louisiana.

Geo-Marine Letters↗

Ecosystems, Ecosystem Services, and Biodiversity

Biodiversity —the variety of life on Earth—provides vital services that support and improve human health and well-being. Ecosystems, which are composed of living things that interact with the physical environment, provide numerous essential benefits to people. These benefits, termed ecosystem services, encompass four primary functions: provisioning materials, such as food and fiber; regulating critical parts of the environment, such as water quality and erosion control; providing cultural services, such as recreational opportunities and aesthetic value; and providing supporting services, such as nutrient cycling. Climate change poses many threats and potential disruptions to ecosystems and biodiversity, as well as to the ecosystem services on which people depend. Building on the findings of the Third National Climate Assessment (NCA3), this chapter provides additional evidence that climate change is significantly impacting ecosystems and biodiversity in the United States. Mounting evidence also demonstrates that climate change is increasingly compromising the ecosystem services that sustain human communities, economies, and well-being. Both human and natural systems respond to change, but their ability to respond and thrive under new conditions is determined by their adaptive capacity, which may be inadequate to keep pace with rapid change. Our understanding of climate change impacts and the responses of biodiversity and ecosystems has improved since NCA3. The expected consequences of climate change will vary by region, species, and ecosystem type. Management responses are evolving as new tools and approaches are developed and implemented; however, they may not be able to overcome the negative impacts of climate change. Although efforts have been made since NCA3 to incorporate climate adaptation strategies into natural resource management, significant work remains to comprehensively implement climate-informed planning. This chapter presents additional evidence for climate change impacts to biodiversity, ecosystems, and ecosystem services, reflecting increased confidence in the findings reported in NCA3. The chapter also illustrates the complex and interrelated nature of climate change impacts to biodiversity, ecosystems, and the services they provide.

Report↗

Municipal solid-waste disposal and ground-water quality in a coastal environment, west-central Florida

Solid waste is defined along with various methods of disposal and the hydrogeologic factors to be considered when locating land-fills is presented. Types of solid waste, composition, and sources are identified. Generation of municipal solid waste in Florida has been estimated at 4.5 pounds per day per person or about 7.8 million tons per year. Leachate is generated when precipitation and ground water percolate through the waste. Gases, mainly carbon dioxide and methane, are also produced. Leachate generally contains high concentrations of dissolved organic and inorganic matter. The two typical hydrogeologic conditions in west-central Florida are (1) permeable sand overlying clay and limestone and (2) permeable sand overlying limestone. These conditions are discussed in relation to leachate migration. Factors in landfill site selection are presented and discussed, followed by a discussion on monitoring landfills. Monitoring of landfills includes the drilling of test holes, measuring physical properties of the corings, installation of monitoring wells, and water-quality monitoring. (USGS)

Water-Resources Investigations Report↗

UAV-based estimate of snow cover dynamics: Optimizing semi-arid forest structure for snow persistence

Seasonal snow cover in the dry forests of the American West provides essential water resources to both human and natural systems. The structure of trees and their arrangement across the landscape are important drivers of snow cover distribution across these forests, varying widely in both space and time. We used unmanned aerial vehicle (UAV) multispectral imagery and Structure-from-Motion (SfM) models to quantify rapidly melting snow cover dynamics and examine the effects of forest structure shading on persistent snow cover in a recently thinned ponderosa pine forest. Using repeat UAV multispectral imagery (n = 11 dates) across the 76 ha forest, we first developed a rapid and effective method for identifying persistent snow cover with 90.2% overall accuracy. The SfM model correctly identified 98% (n = 1280) of the trees, when compared with terrestrial laser scanner validation data. Using the SfM-derived forest structure variables, we then found that canopy shading associated with the vertical and horizontal metrics was a significant driver of persistent snow cover patches ( R 2 = 0.70). The results indicate that UAV image-derived forest structure metrics can be used to accurately predict snow patch size and persistence. Our results provide insight into the importance of forest structure, specifically canopy shading, in the amount and distribution of persistent seasonal snow cover in a typical dry forest environment. An operational understanding of forest structure effects on snow cover will help drive forest management that can target snow cover dynamics in addition to forest health.

Arizona↗

Developing multi-model ensemble projections of ecologically relevant climate variables for Puerto Rico and the US Caribbean

The global increases in surface air temperature are the most widespread and direct consequence of anthropogenic climate change. However, while 21st century temperatures are projected to increase in the Caribbean, the low variability and high average temperatures suggest that impacts on ecosystems and water resources are more likely through changes to the availability, timing, and pattern of moisture. The lack of local-scale climate model information that can resolve the complex topography and small scale climate features hinders the development of robust adaptation strategies. The goal of this project was to develop a suite of local-scale climate projections using dynamic downscaling to aid the development of adaptation strategies in Puerto Rico and the U.S. Virgin Islands (USVI). This project began by engaging the ecologists, hydrologists, and conservation biologists in the region to determine the most valuable types of information to aid research and decision making. The final product provides projections of future climate at a 2km horizontal resolution based on three global climate models and two regional climate models for a scenario with high greenhouse gas emissions. Results from the projections suggest that for Puerto Rico, annual temperature would increase between 1°C and 1.3°C by mid-century with larger temperature increases located in the interior portion of the island. Precipitation totals decrease for much of the island with island average decline between 12% and 19%, with some potentially large localized decreases exceeding 30%. The projected changes for the USVI are dominated by the surrounding ocean environment. The resulting projections will be provided to stakeholders in the region via the USGS and the CLCC.

Puerto Rico↗

Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

Successful wildlife management depends upon coordination and consultation with local communities. However, much of the research used to inform management is often derived solely from data collected directly from wildlife. Indigenous people living in the Arctic have a close connection to their environment, which provides unique opportunities to observe their environment and the ecology of Arctic species. Further, most northern Arctic communities occur within the range of polar bears ( nanuq , Ursus maritimus ) and have experienced significant climatic changes. Here, we used semi-structured interviews from 2017 to 2019 to document Iñupiaq knowledge of polar bears observed over four decades in four Alaskan communities in the range of the Southern Beaufort Sea polar bear subpopulation: Wainwright, Utqiaġvik, Nuiqsut, and Kaktovik. All but one of 47 participants described directional and notable changes in sea ice, including earlier ice breakup, later ice return, thinner ice, and less multiyear pack ice. These changes corresponded with observations of bears spending more time on land during the late summer and early fall in recent decades—observations consistent with scientific and Indigenous knowledge studies in Alaska, Canada, and Greenland. Participants noted that polar bear and seal body condition and local abundance either varied geographically or exhibited no patterns. However, participants described a recent phenomenon of bears being exhausted and lethargic when arriving on shore in the summer and fall after extensive swims from the pack ice. Further, several participants suggested that maternal denning is occurring more often on land than sea ice. Participants indicated that village and regional governments are increasingly challenged to obtain resources needed to keep their communities safe as polar bears spend more time on land, an issue that is likely to be exacerbated both in this region and elsewhere as sea ice loss continues.

Alaska↗

Specification aggregate quarry expansion - A case study demonstrating sustainable management of natural aggregate resources

Many countries, provinces, territories, or states in the European Union, Australia, Canada, the United States, and elsewhere have begun implementing sustainability programs, but most of those programs stop short of sustainable management of aggregate resources. Sustainable practices do not always have to be conducted under the title of sustainability. This case study describes how Lafarge, a large multinational construction materials supplier, implemented the principles of sustainability even though there was an absence of existing local government policies or procedures addressing sustainable resource management. Jefferson County, Colorado, USA, is one of three counties in the six-county Denver, Colorado, region that has potentially available sources of crushed stone. Crushed stone comprises 30 percent of the aggregate produced in the area and plays a major role in regional aggregate resource needs. Jefferson County is home to four of the five crushed stone operations in the Denver region. Lafarge operates one of those four quarries. Lafarge recently proposed to expand its reserves by exchanging company-owned land for existing dedicated open space land adjacent to their quarry but owned by Jefferson County. A similar proposal submitted about 10 years earlier had been denied. Contrary to the earlier proposal, which was predicated on public relations, the new proposal was predicated on public trust. Although not explicitly managed under the moniker of sustainability, Lafarge used basic management principles that embody the tenets of sustainability. To achieve the goals of sustainable aggregate management where no governmental policies existed, Lafarge not only assumed their role of being a responsible corporate and environmental member of the community, but also assumed the role of facilitator to encourage and enable other stakeholders to responsibly resolve legitimate concerns regarding the Lafarge quarry proposal. Lafarge successfully presented an enlightened proposal where the county will gain 745 acres of new open space land in exchange for 60 acres of current open space land adjacent to the quarry. The process involved collaborative efforts by all stakeholders and resulted in an outcome that balances the needs of society, the environment, and business.

Colorado↗

Evaluation of passive samplers for cyanotoxin detection by immunoassay and chromatographic-mass spectrometry

Harmful algal blooms, particularly cyanobacterial harmful algal blooms, threaten aquatic ecosystems, drinking water supplies, and recreational resources. In 2019, the U.S. Geological Survey, in collaboration with the New York State Department of Environmental Conservation, deployed solid phase adsorption toxin tracking (SPATT) samplers in Seneca Lake, Owasco Lake, and Skaneateles Lake to monitor the cyanotoxins microcystins, cylindrospermopsins, anatoxins, and saxitoxins. SPATT samplers can passively adsorb dissolved cyanotoxins over time, providing time-integrated data capable of detecting low concentrations of cyanotoxins that traditional discrete sampling may miss. SPATT samples were analyzed using enzyme-linked immunosorbent assay (ELISA), liquid chromatography with mass spectrometry (LC–MS), and with tandem mass spectrometry (LC–MS/MS). The effects of ELISA-required preservative on measurements by mass spectrometry methods were also evaluated. SPATT samplers consistently detected microcystins and anatoxins more frequently than concurrent discrete sampling. ELISA results often showed higher cyanotoxin concentrations than LC–MS/MS, likely due to interference from dissolved organic matter and the ability of ELISA to detect a broader range of congeners. The addition of preservative influenced results for some analytes, particularly microcystins, which showed higher concentrations in preserved samples. Limitations in ELISA methods for cylindrospermopsins and saxitoxins were identified, potentially related to cross-reactivity, low sensitivity, or other matrix interferences. This study demonstrates the utility of SPATT samplers in capturing cyanotoxin variability, especially in environments with low cyanotoxin levels or ephemeral blooms. Further research could help improve the reliability of ELISA and other analytical methods in freshwater ecosystems.

New York↗

Toxicity of 6PPD alternatives to salmonid cell lines

Stormwater runoff in urban areas introduces numerous anthropogenic chemicals into surrounding aquatic environments. One such chemical is 6PPD ( N -(1,3-Dimethylbutyl)- N ’-phenyl- p- phenylenediamine), the primary antidegradant responsible for protecting tire rubber from ozone-induced degradation and cracking. When exposed to ozone on the road surface 6PPD is transformed into the toxic transformation product 6PPD-quinone (6PPDQ). This compound is highly lethal to coho salmon ( O ncorhynchus kisutch ), and 24 hour 50% lethal concentrations (LC 50 ; 41-95 ng/L) are frequently detected in urban streams during stormwater runoff events 1-5 . The highest stream concentrations of 6PPDQ and most extensive coho salmon mortality occur in high-traffic urban areas, where tire wear particles accumulate due to the frequent braking and acceleration of cars 6 . In the Seattle area, some coho salmon-bearing streams can lose over 90% of returning females prior to spawning due to 6PPDQ-containing runoff 7 . Prespawn loss of this magnitude could result in the extinction of some urban spawning populations 8 . Importantly, the lethal effects of 6PPDQ have been observed in several other salmonid species, indicating that its impact may threaten fish health for urban aquatic environments globally 9-11 . The ubiquity of 6PPD in automobile tires, high toxicity of the transformation product 6PPDQ, and prevalence of 6PPD and 6PPDQ in environmental matrices has spurred investigations into alternative rubber antiozonants to replace 6PPD that retain tire performance while reducing ecological harm. A technical memorandum provided to the legislature by the Washington State Department of Ecology summarized a list of potential 6PPD alternatives requiring further study, including several structurally similar p-phenylenediamines (PPDs) 12 . However, the structural similarity of other PPDs to 6PPD and their known production of quinone transformation products 13 raises concerns that they may elicit similar toxic effects as 6PPDQ. Currently, investigations into the toxicity of proposed PPD alternatives or their ozonated transformation products in coho salmon are limited, representing a significant data gap in evaluating whether they offer improved environmental safety over 6PPD. This project investigated the toxicity of proposed alternative rubber antiozonants in vitro using immortalized cell lines derived from three salmonid species with known differences in sensitivity to 6PPDQ (coho salmon, Chinook salmon ( O. tshawytscha ), rainbow trout ( O. mykiss )) 1 . These immortalized cell lines replicate toxic responses observed in in vivo studies, while enabling higher-throughput testing and reducing the need for animal use and other resource-intensive procedures. The antiozonants and their transformation products selected for testing were chosen based on multiple criteria, including their inclusion in the Ecology technical memorandum, structural substitutions (e.g., branched/cyclic alkyl vs aryl substitutions), commercial availability, and input from the Washington State Department of Ecology and other industry experts.

Report↗

The National Climate Change and Wildlife Science Center annual report for 2013

In 2008, Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS). The center was formed to respond to the demands of natural resource managers for rigorous scientific information and effective tools for assessing and responding to climate change. Located at the USGS National Headquarters in Reston, Va., the NCCWSC has invested more than $93 million (through FY13) in cutting-edge climate change research and, in response to Secretarial Order No. 3289, established and is managing eight regional Department of Interior (DOI) Climate Science Centers (CSCs). In 2013: The DOI CSCs awarded nearly $7 million in funding to universities and other partners for climate and land-use change research. The scientific work of the NCCWSC-CSC enterprise moved toward projects that focus on ‘Science Infrastructure and Capacity Building’ and ‘Thematic Science’. A permanent director, David Helweg, Ph.D., was hired for the Pacific Islands CSC (PI CSC), completing the CSC leadership team. Staff scientists were hired at the Alaska (AK), Northeast (NE), and Southeast (SE) CSCs. Each of the eight CSCs completed the formation of regional Stakeholder Advisory Committees (SACs) and a national advisory committee (ACCCNRS) was created to oversee the NCCWSC-CSC enterprise. NCCWSC staff worked on creating a searchable public database on climate change vulnerability assessments. NCCWSC scientists authored articles in a special issue of the Ecological Society of America’s journal Frontiers in Ecology and the Environment, which was devoted to an assessment of climate change effects on biodiversity and ecosystems, and the consequences for people. Learn more about these achievements in The National Climate Change and Wildlife Science Center Annual Report for 2013 .

Circular↗

Effects of groundwater pumping in the lower Apalachicola-Chattahoochee-Flint River basin

USGS developed a groundwater-flow model of the Upper Floridan aquifer in lower Apalachicola-Chattahoochee-Flint River basin in southwest Georgia and adjacent parts of Alabama and Florida to determine the effect of agricultural groundwater pumping on aquifer/stream flow within the basin. Aquifer/stream flow is the sum of groundwater outflow to and inflow from streams, and is an important consideration for water managers in the development of water-allocation and operating plans. Specifically, the model was used to evaluate how agricultural pumping relates to 7Q10 low streamflow, a statistical low flow indicative of drought conditions that would occur during seven consecutive days, on average, once every 10 years. Argus ONETM, a software package that combines a geographic information system (GIS) and numerical modeling in an Open Numerical Environment, facilitated the design of a detailed finite-element mesh to represent the complex geometry of the stream system in the lower basin as a groundwater-model boundary. To determine the effects on aquifer/stream flow of pumping at different locations within the model area, a pumping rate equivalent to a typical center-pivot irrigation system (50,000 ft3/d) was applied individually at each of the 18,951 model nodes in repeated steady-state simulations that were compared to a base case representing drought conditions during October 1999. Effects of nodal pumping on aquifer/stream flow and other boundary flows, as compared with the base-case simulation, were computed and stored in a response matrix. Queries to the response matrix were designed to determine the sensitivity of targeted stream reaches to agricultural pumping. Argus ONE enabled creation of contour plots of query results to illustrate the spatial variation across the model area of simulated aquifer/streamflow reductions, expressed as a percentage of the long-term 7Q10 low streamflow at key USGS gaging stations in the basin. These results would enable water managers to assess the relative impact of agricultural pumping and drought conditions on streamflow throughout the basin, and to develop mitigation strategies to conserve water resources and preserve aquatic habitat.

Alabama, Georgia, Florida↗

Persistence of DNA in carcasses, slime and avian feces may affect interpretation of environmental DNA data

The prevention of non-indigenous aquatic invasive species spreading into new areas is a goal of many resource managers. New techniques have been developed to survey for species that are difficult to capture with conventional gears that involve the detection of their DNA in water samples (eDNA). This technique is currently used to track the invasion of bigheaded carps (silver carp and bighead carp; Hypophthalmichthys molitrix and H. nobilis ) in the Chicago Area Waterway System and Upper Mississippi River. In both systems DNA has been detected from silver carp without the capture of a live fish, which has led to some uncertainty about the source of the DNA. The potential contribution to eDNA by vectors and fomites has not been explored. Because barges move from areas with a high abundance of bigheaded carps to areas monitored for the potential presence of silver carp, we used juvenile silver carp to simulate the barge transport of dead bigheaded carp carcasses, slime residue, and predator feces to determine the potential of these sources to supply DNA to uninhabited waters where it could be detected and misinterpreted as indicative of the presence of live bigheaded carp. Our results indicate that all three vectors are feasible sources of detectable eDNA for at least one month after their deposition. This suggests that current monitoring programs must consider alternative vectors of DNA in the environment and consider alternative strategies to minimize the detection of DNA not directly released from live bigheaded carps.

PLoS ONE↗