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At least 1,405 records · Page 78Linked to original sources
USGS2022

Documenting the multiple facets of a subsiding landscape from coastal cities and wetlands to the continental shelf

Land subsidence is a settling, sinking, or collapse of the land surface. In the southeastern United States, subsidence is frequently observed as sinkhole collapse in karst environments, wetland degradation and loss in coastal and other low-lying areas, and inundation of coastal urban communities. Human activities such as fluid extraction, mining, and overburden alteration can cause or exacerbate subsidence, which can result in damage to infrastructure and resources. Subsidence is a hazard that takes place throughout the United States; however, a systematic approach to recognize and develop informed responses to the drivers of subsidence has not yet been fully established. To address this problem, the U.S. Geological Survey (USGS) Southeast Region (SER) funded the gathering of a team of interdisciplinary USGS scientists to promote scientific collaboration. Southeast Region scientists welcomed scientists from other regions (see table 1.1 in Appendix 1) in September 2018 at the St. Petersburg Coastal and Marine Science Center (SPCMSC) in Florida for the first workshop of the Subsidence Flex Team (SFT) (see Appendix 2 for agenda). The SFT set out to review subsidence-related research and technology and develop a unifying framework for describing the processes and hazards associated with land subsidence. A more comprehensive understanding of subsidence hazards could help to inform regional vulnerability assessments that would prove invaluable to the public, community developers, policy makers, and resource managers in both inland and coastal states. The SFT analyzed USGS strengths and weaknesses to identify existing infrastructure and capabilities that could be leveraged to create a comprehensive and far-reaching subsidence-monitoring and mitigation program. Over the course of the 2-day workshop, interdisciplinary understandings of the processes and hazards related to subsidence were explored through individual presentations and group discussion. With all perspectives considered, the SFT recommended that subsidence-related research develop scientific approaches and metrics by which the subsidence component can be isolated and quantified in order to protect both the environment and human infrastructure from harm.

Alabama, Florida, Louisiana, Mississippi↗
USGS1983

Streamflow and water-quality data for lake and wetland inflows and outflows in the Twin Cities metropolitan area, Minnesota, 1981-82

A study of runoff to selected lakes was done in the Twin Cities metropolitan area from July 1981 to December 1982. The purpose of the study was to determine differences in nutrient-loading characteristics for lakes with and without wetlands and settling ponds. The study also quantified nutrient loading to lakes on a storm, seasonal, and annual basis, complementing an inlake water-quality study of these lakes done by the Metropolitan Council. Discharge and water-quality data were collected periodically during 1981 and continuously during 1982 at 22 sites located in seven lake watersheds Bryant Lake, Lake Elmo, Fish Lake, Lake George, Lake Riley, Spring Lake, and Square Lake. Basin characteristics and land use were determined for each watershed. Recording instruments provided continuous discharge records at 14 sites and continuous rainfall records at six sites. Automatic water-quality samplers were used at lake inlets. The automatic samplers collected samples at 1- to 2-hour intervals during storms. Lake-outlet samples were collected manually on a weekly basis during flow. Samples were analyzed for suspended solids and nutrients. Atmospheric-input data were collected at eight sites from September 23 to November 1, 1982. Discharge and water-quality data were used to calculate storm, seasonal, and annual loads of total suspended solids, volatile suspended solids, total phosphorus, dissolved phosphorus, nitrite-plus-nitrate nitrogen, ammonia nitrogen, and ammonia-plus-organic nitrogen. All data collected during the study are documented in tables and graphs that contain (1) watershed characteristics and land use; (2) storm concentrations; (3) storm, seasonal, and annual loads; (4) storm hydrographs; (5) atmospheric-input concentrations and loads; (6) storm, seasonal, and annual precipitation totals; and (7) results of quality-assurance tests.

Minnesota↗
USGS1995

Climatic and lake temperature data for Wetland P1, Cottonwood Lake Area, Stutsman County, North Dakota, 1982-87

Research on the hydrology of Wetland P1 and the Cottonwood Lake Area includes the study of evaporation. Presented here in a graphical format are those data collected during the open-water seasons of 1982-87 that were needed for energy- budget and mass-transfer evaporation studies. The data include air temperatures, water surface and lake-bottom temperatures, windspeed, radiation, humidity, and precipitation. Data were collected at a raft station and two land stations.

Open-File Report↗
USGS2002

Geochemistry of surface and pore water at USGS coring sites in wetlands of South Florida, 1994 and 1995

In this report, we present preliminary data on surface and pore water geochemistry from 22 sites in south Florida sampled during 1994 and 1995. These results are part of a larger study designed to evaluate the role of biogeochemical processes in sediments in the cycling of carbon, nitrogen, phosphorus, and sulfur in the south Florida ecosystem. The data are briefly discussed in regard to regional trends in the concentrations of chemical species, and general diagenetic processes in sediments. These results are part of a larger study designed to evaluate the role of biogeochemical processes in sediments in the cycling of carbon, nitrogen, phosphorus, and sulfur in the south Florida ecosystem. These elements play a crucial role in regulating organic sedimentation, nutrient dynamics, redox conditions, and the biogeochemistry of mercury in the threatened wetlands of south Florida. Pore water samples for chemical analyis were obtained using a piston corer/squeezer designed to avoid compression of the sediment and avoid oxidation and contamination of the pore water samples. Results show distinct regional trends in both surface water and pore water geochemistry. Most chemical species in surface and pore water show peak concentrations in Water Conservation Area 2A, with diminishing concentrations to the south and west into Water Conservation Area 3A, and Everglades National Park. The largest differences observed were for phosphate and sulfide, with concentrations in pore waters in Water Conservation Area 2A up to 500x higher than concentrations observed in freshwater marsh areas of Water Conservation Area 3A and Everglades National Park. Sites near the Hillsboro Canal in Water Conservation Area 2A are heavily contaminated with both phosphorus and sulfur. Pore water profiles for dissolved reactive phosphate suggest that recycling of phosphorus at these contaminated sites occurs primarily in the upper 20 cm of sediment. High levels of sulfide in pore water in Water Conservation Area 2A may inhibit mercury methylation here. At sites in Water Conservation Area 3A south of Alligator Alley, sulfide levels are much lower and sulfate reduction in the sediments here may be conducive to methyl mercury formation. Concentration versus depth profiles of biogeochemically important chemical species in pore water at most sites are smoth curves amenable to modelling using standard diagenetic equations. This should allow prediction of rates of biogeochemical processes in these sediments for incorporation in ecosystem models.

Florida↗
USGS2005

Changes in streamflow patterns related to hydrologic restoration of a sedge fen wetland in Seney National Wildlife Refuge, Michigan, 1998-2004

Vast expanses of sedge fen in Schoolcraft County in Michigan's Upper Peninsula were ditched and diked in the early to mid-1900s to promote agricultural development and create waterfowl habitat. Unintended consequences of these actions were far reaching and included the deposition of large amounts of sand in the Manistique River. In 2002, the U.S. Fish and Wildlife Service, which now manages much of the wetland as part of Seney National Wildlife Refuge, attempted to restore streamflow to Walsh Creek and overland flow downgradient of Walsh Ditch, near C-3 Pool. Streamflow data were collected before and after remediation activities. These data indicate that efforts to restore flow to Walsh Creek were partially successful, but it is unclear whether overland flow was restored downgradient from Walsh Ditch. Alternatives for future evaluation of restoration of flow to Walsh Creek include monitoring streamflow at three easily accessible locations. Restoration of overland flow downgradient from Walsh Ditch can be assessed in the future by monitoring flows at three additional sites. Restoration of either site can be assessed by monitoring vegetation shifts, possibly with aerial or satellite imagery.

Michigan↗
USGS1990

Vegetative changes in a wetland in the vicinity of a well field, Dade County, Florida

Plant communities present in 1978 and 1986 were analyzed at 250 random points on stereoscopic pairs of aerial photographs for four study sites in the vicinity of the Northwest Well Field in Dade County, Florida. Sites NW and NE lie northwest of the well field beyond the cone of depression. Site SW lies in the outer part of the cone, and site SE lies within the cone of depression. Relative frequency values for several plant types including herbs, shrubs-small trees, and trees were analyzed by the Heterogeneity G-test to determine heterogeneity among sites in 1978 and 1986. In 1978, all four sites were dominated by plant communities having herbs, shrubs, or a mixture thereof. The communities at sites NW and NE were similar, and those at SE and SW were somewhat similar. In 1986, sites NW, NE, and SE were dominated by a mixture of shrubs and trees. Only at site SW was the relative frequency of occurrence of herbaceous plants still high. At each site, there was a decrease in herbaceous vegetation and an increase in woody vegetation during this period, with the increase in trees being greatest at site SE. Time between the start of the well-field operation in May 1983 and the January 1986 photographs was insufficient to allow determination of any direct effects of the well field on the vegetation. Ground-level observations in 1987 and 1988 indicate a trend toward continued increase in dominance of woody plants and a decrease in herbaceous wetland vegetation. Development of a forest of the exotic pest tree melaleuca is occurring at all four sites, but especially at site SE. Vegetative changes between 1978 and 1986 are attributed to an invasion of the exotic species melaleuca, a shortened hydroperiod, and natural succession within the plant communities.

Florida↗
USGS2022

Ventilation systems in wetland plant species

Molecular oxygen and carbon dioxide may be limited for aquatic plants, but they have various mechanisms for acquiring these gases from the atmosphere, soil, or metabolic processes. The most common adaptations of aquatic plants involve various aerenchymatic structures, which occur in various organs, and enable the throughflow of gases. These gases can be transferred in emergent plants by molecular diffusion, pressurized gas flow, and Venturi-induced convection. In submerged species, the direct exchange of gases between submerged above-ground tissues and water occurs, as well as the transfer of gases via aerenchyma. Photosynthetic O 2 streams to the rhizosphere, while soil CO 2 streams towards leaves where it may be used for photosynthesis. In floating-leaved plants anchored in the anoxic sediment, two strategies have developed. In water lilies, air enters through the stomata of young leaves, and streams through channels towards rhizomes and roots, and back through older leaves, while in lotus, two-way flow in separate air canals in the petioles occurs. In Nypa Steck palm, aeration takes place via leaf bases with lenticels. Mangroves solve the problem of oxygen shortage with root structures such as pneumatophores, knee roots, and stilt roots. Some grasses have layers of air on hydrophobic leaf surfaces, which can improve the exchange of gases during submergence. Air spaces in wetland species also facilitate the release of greenhouse gases, with CH 4 and N 2 O released from anoxic soil, which has important implications for global warming.

Diversity↗
USGS2021

Watershed and estuarine controls both influence plant community and tree growth changes in tidal freshwater forested wetlands along two U.S. mid-Atlantic rivers

The tidal freshwater zone near the estuarine head-of-tide is potentially sensitive to both sea-level rise and associated salinity increases as well as changing watershed inputs of freshwater and nutrients. We evaluated the vegetation response of tidal freshwater forested wetlands (TFFW) to changes in nontidal river versus estuarine controls along the longitudinal gradient of the Mattaponi and Pamunkey rivers in the Mid-Atlantic USA. The gradient included nontidal freshwater floodplain (NT) and upper tidal (UT), lower tidal (LT), and stressed tidal forest transitioning to marsh (ST) TFFW habitats on both rivers. Plot-based vegetation sampling and dendrochronology were employed to examine: (1) downriver shifts in plant community composition and the structure of canopy trees, understory trees/saplings/shrubs and herbs, tree basal-area increment (BAI) and (2) interannual variability in BAI from 2015 dating back as far as 1969 in relation to long-term river and estuary monitoring data. With greater tidal influence downstream, tree species dominance shifted, live basal area generally decreased, long-term mean BAI of individual trees decreased, woody stem mortality increased, and live herbaceous vegetative cover and richness increased. Acer rubrum , Fagus grandifolia , Ilex opaca , and Fraxinus pennsylvanica dominated NT and UT sites, with F. pennsylvanica and Nyssa sylvatica increasingly dominating at more downstream tidal sites. Annual tree BAI growth was positively affected by nontidal river flow at NT and UT sites which were closer to the head-of-tide, positively influenced by small salinity increases at LT and ST sites further downstream, and positively influenced by estuarine water level throughout the gradient; nutrient influence was site specific with both positive and negative influences. The counterintuitive finding of salinity increasing tree growth at sites with low BAI is likely due to either competitive growth release from neighboring tree death or enhanced soil nutrient availability that may temporarily mitigate the negative effects of low-level salinization and sea-level increases on living TFFW canopy trees, even as overall plant community conversion to tidal marsh progresses.

Virginia↗
USGS2021

Coastal wetland shoreline change monitoring: A comparison of shorelines from high-resolution WorldView satellite imagery, aerial imagery, and field surveys

Shoreline change analysis is an important environmental monitoring tool for evaluating coastal exposure to erosion hazards, particularly for vulnerable habitats such as coastal wetlands where habitat loss is problematic world-wide. The increasing availability of high-resolution satellite imagery and emerging developments in analysis techniques support the implementation of these data into shoreline monitoring. Geospatial shoreline data created from a semi-automated methodology using WorldView (WV) satellite data between 2013 and 2020 were compared to contemporaneous field-surveyed Global Position System (GPS) data. WV-derived shorelines were found to have a mean difference of 2 ± 0.08 m of GPS data, but accuracy decreased at high-wave energy shorelines that were unvegetated, bordered by sandy beach or semi-submergent sand bars. Shoreline change rates calculated from WV imagery were comparable to those calculated from GPS surveys and geospatial data derived from aerial remote sensing but tended to overestimate shoreline erosion at highly erosive locations (greater than 2 m yr −1 ). High-resolution satellite imagery can increase the spatial scale-range of shoreline change monitoring, provide rapid response to estimate impacts of coastal erosion, and reduce cost of labor-intensive practices.

Remote Sensing↗
USGS2015

Evaluating the piscicide rotenone as an option for eradication of invasive Mozambique tilapia in a Hawaiian brackish-water wetland complex

Mozambique tilapia Oreochromis mossambicus were recently discovered in ‘Aimakapā Fishpond, a 12-hectare brackish-water wetland complex in Kaloko-Honokōhau National Historical Park, on the Island of Hawai’i. As a possible eradication method, we evaluated rotenone, a natural piscicide used in fish management and the active ingredient in plants traditionally used by indigenous Hawaiians for capturing fish. To assess rotenone’s efficacy in killing tilapia and effects on non-target species, laboratory toxicity tests involved exposing organisms to various concentrations of liquid CFT Legumine (5% rotenone) in static trials of 48-h to 72-h duration. Test organisms included: Mozambique tilapia, non-native guppy Poecilia reticulata , the non-native odonate Rambur’s forktail Ischnura ramburii , native feeble shrimp Palaemon debilis , and native ‘ōpae’ula shrimp Halocaridina rubra . All organisms and water used in tests were obtained from ‘Aimakapā (12.6–12.7 ppt salinity), or, for H. rubra , an anchialine pool (15.0–15.2 ppt salinity). Survival analyses indicated CFT Legumine concentrations >3 ppm (>0.15 mg/L rotenone) achieved 100% mortality of tilapia and 93% of guppies within 24 h, with most tilapia killed by 6 h and most guppies by 2 h. Little or no mortality was observed among invertebrate exposed to 1 to 5 mg/L CFT Legumine: 0% mortality for ‘ōpae’ula shrimp, 4% for feeble shrimp; and 16% for odonate larvae. The 48 h LC50 values for Mozambique tilapia and guppy were 0.06 and 0.11 mg/L rotenone, respectively. Results demonstrate rotenone’s potential for non-native fish eradication in brackish-water habitats, with benefit of low mortality to certain macro-invertebrates. High rotenone tolerance displayed by ‘ōpae’ula shrimp is noteworthy. Invasive fish are common in anchialine pools, threatening existence of shrimp and other invertebrate fauna. Although rotenone’s effects on freshwater organisms have been well studied, our research represents one of only a few controlled laboratory experiments quantitatively assessing rotenone tolerance of brackish or marine fauna.

Hawaii↗
USGS2014

Productivity of functional guilds of fishes in managed wetlands in coastal South Carolina

In coastal South Carolina, many wetlands are impounded and managed as migratory waterfowl habitat. Impoundment effects on fish production and habitat quality largely are unknown. We used the size-frequency method to estimate summer production of fish guilds in three impoundments along the Combahee River, South Carolina. We predicted that guild-specific production would vary with impoundment salinity, which ranged from 3 to 21 practical salinity units. We expected that marine species that use the estuary as nursery habitat would have greatest production in the impoundment with the highest salinity regime, and that species that inhabit the upper reaches of the estuary would have greatest production in the impoundment with the lowest salinity regime. Finally, we expected that estuarine species would be highly productive in all study impoundments, because these species can reproduce within these structures. We found that guild-specific productivity varied both among years and among impoundments, generally following salinity gradients, though to a lesser extent than expected. Our guild-specific estimates of fish productivity fell on the low end of the range of previously published estuarine fish production estimates. Additionally, we observed large mortality events in the study impoundments each summer. The results of our study indicate that during the summer, the study impoundments provided poor-quality fish habitat to all guilds.

South Carolina↗
USGS2011

Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO 2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find in a series of preliminary experiments that organic decomposition rates increase by about 20% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, three times as high as the response of salt marsh productivity to temperature warming, and greater than the productivity response associated with elevated CO 2 in C 3 marsh plants. Although the experiments were simple and of short duration, they suggest that enhanced CO 2 and warmer temperatures could actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments.

Virginia↗
USGS2011

Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that 5 elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find that organic decomposition rates increase by about 12% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, twice as high as the response of salt marsh productivity to temperature warming, and roughly equivalent to the productivity response associated with elevated CO2 10 in C3 marsh plants. Therefore, enhanced CO2 and warmer temperatures may actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between 15 climate, sea level rise, and carbon emissions in coastal environment

Biogeosciences Discussions↗
USGS2003

Characterization of Pasteurella multocida isolates from wetland ecosystems during 1996 to 1999

We cultured 126 Pasteurella multocida isolates, 92 from water and 34 from sediment samples collected from wetlands in the Pacific and Central flyways of the United States between 1996 and 1999. Most (121) of the isolates were P. multocida serotype 1, but serotypes 3, 3/4, 10, and 11 were also found. Many (82) of the isolates were further characterized by DNA fingerprinting procedures and tested in Pekin ducks for virulence. Almost all the serotype 1 isolates we tested caused mortality in Pekin ducks. Serotype 1 isolates varied in virulence, but the most consistent pattern was higher mortality in male ducks than in females. We found no evidence that isolates found in sediment vs. water, between Pacific and Central flyways, or during El Nino years had consistently different virulence. We also found a number of non-serotype 1 isolates that were avirulent in Pekin ducks. Isolates had DNA fingerprint profiles similar to those found in birds that died during avian cholera outbreaks.

Journal of Wildlife Diseases↗
USGS1983

Water storage capacity of natural wetland depressions in the Devils Lake basin of North Dakota

Photogrammetric mapping techniques were used to derive the water storage capacities of natural wetland depressions other than lakes in the Devils Lake Basin of North Dakota. Results from sample quarter-section areas were expanded to the entire basin. Depressions in the Devils Lake Basin have a maximum storage capacity of nearly 811,000 cubic dekameters (657,000 acre-feet). The depressions store about 72 percent of the total runoff volume from a 2-year-frequency runoff and about 41 percent of the total runoff volume from a 100-year-frequency runoff.

Journal of Soil and Water Conservation↗
USGS1978

Waterfowl nesting on small man-made islands in prairie wetlands

Small islands constructed in prairie wetlands were attractive nesting sites for mallards (Anas platyrhynchos) and Canada geese (Branta canadensis). Nest densities of mallards on islands averaged 135 per ha compared to 0.03 per ha on adjacent upland habitats. Construction time averaged 2 hours per island and cost $50. No maintenance was required during the first 10 years.

Wildlife Society Bulletin↗