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At least 991 records · Page 55Linked to original sources
USGS2024

Mitigating climate change by abating coal mine methane: A critical review of status and opportunities

Methane has a short atmospheric lifetime compared to carbon dioxide (CO 2 ), ∼decade versus ∼centuries, but it has a much higher global warming potential (GWP), highlighting how reducing methane emissions can slow the rate of climate change. When considering the contribution of greenhouse gas (GHG) emissions to current global warming (2010–2019) relative to the industrial revolution (1850–1900) levels, methane contributes 0.5 °C or ∼ a third of the total. The most recent post-2023 global estimates of methane emissions by bottom-up (BU) and top-down (TD) approaches for the coal mining sector are in the range of ∼41 ± 3 Tg yr −1 and 33 ± 5 Tg yr −1 , respectively. This divergence, notwithstanding overlapping confidence intervals, is a result of differences between applied TD global inversion models and BU emission inventories. Further research can help to better refine emissions from the various contributing coal mine methane (CMM) emissions sources. The coal mining sector accounts for over 10 % of global anthropogenic methane emissions. The contribution of CMM emissions to the global budget have increased since 2000, although upward and downward regional trends have been observed.

International Journal of Coal Geology↗
USGS2011

From agricultural intensification to conservation: Sediment transport in the Raccoon River, Iowa, 1916-2009

Fluvial sediment is a ubiquitous pollutant that negatively aff ects surface water quality and municipal water supply treatment. As part of its routine water supply monitoring, the Des Moines Water Works (DMWW) has been measuring turbidity daily in the Raccoon River since 1916. For this study, we calibrated daily turbidity readings to modern total suspended solid (TSS) concentrations to develop an estimation of daily sediment concentrations in the river from 1916 to 2009. Our objectives were to evaluate longterm TSS patterns and trends, and relate these to changes in climate, land use, and agricultural practices that occurred during the 93-yr monitoring period. Results showed that while TSS concentrations and estimated sediment loads varied greatly from year to year, TSS concentrations were much greater in the early 20th century despite drier conditions and less discharge, and declined throughout the century. Against a backdrop of increasing discharge in the Raccoon River and widespread agricultural adaptations by farmers, sediment loads increased and peaked in the early 1970s, and then have slowly declined or remained steady throughout the 1980s to present. With annual sediment load concentrated during extreme events in the spring and early summer, continued sediment reductions in the Raccoon River watershed should be focused on conservation practices to reduce rainfall impacts and sediment mobilization. Overall, results from this study suggest that eff orts to reduce sediment load from the watershed appear to be working. ?? 2011 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Journal of Environmental Quality↗
USGS2022

Temporal trends in macroscopic indicators of fish health in the South Branch of the Potomac River

Over recent decades, the South Branch of the Potomac River, WV, has experienced fish kills and episodes of suppressed health in adult fishes that have spanned small stretches to nearly 120 km of contiguous habitat. Although factors such as endocrine disruption, chemical contaminants, and infectious agents have been detected, no single causal mechanism has been identified. To gain information about the temporal nature of abnormalities, differences in life stage impacts, and potential risk factors, investigations of rank scores of macroscopic indicators of fish health were conducted utilizing seasonal and annual boat electrofishing surveys for Smallmouth Bass Micropterus dolomieu (SMB) and Golden Redhorse Moxostoma erythrurum (GDR). Gill and body abnormalities were assigned rank scores for each fish based on visual severity and were tested for correlation with seasonal climatic (flow and stream temperature) and environmental factors (stream pH, dissolved oxygen, and turbidity). Analyses between juveniles and adults for these species indicated body lesions were more common for adult GDR and gill lesions were more common for adult SMB. Significantly higher rank sums of adult gill abnormalities corresponded with heavy annual mortality of SMB from ages 2-3 (86%), the age at which this species transitions from juvenile to adult length. Higher ranks were frequently assigned to fish of both species for gill and body/fin lesions during summer and fall samples. Low stream discharges and lower pH units correlated with elevations of body raised lesion (GDR) and erosions (GDR and SMB), as well as erosions of gill lamellae (SMB). This study connects the disciplines of fisheries management, fish health, and environmental monitoring, providing information gained through tracking macroscopic conditions of these two indicator species for the focusing of future studies and better understanding risks to fish health.

West Virginia↗
USGS1991

Detectability of the effects of a hypothetical temperature increase on the Thornthwaite moisture index

Climatic changes that result from increasing concentrations of atmospheric carbon dioxide may affect the availability of water for vegetation, groundwater recharge, runoff, and human consumption. Most studies of the effects of climatic change on water resources focus on changes in mean characteristics of hydrologic variables and do not consider the effects of these changes amid natural climatic variability. In this study, the Thornthwaite moisture index, an index of the supply of water in an area (precipitation) relative to the climatic demand for water (potential evapotranspiration), was used to examine the effects of a hypothetical increase in air temperature on moisture conditions in the United States. The effects of a gradual increase in air temperature at the rate of 4°C per 100 years, with no accompanying change in precipitation, was used to induce a change in Thornthwaite moisture index values for the United States in order to: (i) determine the relation between natural variability in climate and the time needed for significant trends in the moisture index to occur in response to hypothetical warming; (ii) identify the characteristics of areas (e.g. wet/cool, hot/dry etc.) that are most likely to be the first to experience significant changes in the moisture index given the hypothetical temperature increase. The increased temperature resulted in increased potential evapotranspiration and a decrease in the moisture index across the United States. Decreases in the moisture index were greatest in cool/wet regions and least in hot/dry regions. The time required to detect significant trends in the moisture index was a function of both the magnitude of change in the moisture index and the natural year-to-year variability of the moisture index. In general, when the ratio of the magnitude of change in the moisture index to the magnitude of variability was large, the time required to detect significant trends was short. This ratio was largest in cool/wet regions resulting in the shortest detection times.

Journal of Hydrology↗
USGS2017

Projecting impacts of climate change on water availability using artificial neural network techniques

Lago Loíza reservoir in east-central Puerto Rico is one of the primary sources of public water supply for the San Juan metropolitan area. To evaluate and predict the Lago Loíza water budget, an artificial neural network (ANN) technique is trained to predict river inflows. A method is developed to combine ANN-predicted daily flows with ANN-predicted 30-day cumulative flows to improve flow estimates. The ANN application trains well for representing 2007–2012 and the drier 1994–1997 periods. Rainfall data downscaled from global circulation model (GCM) simulations are used to predict 2050–2055 conditions. Evapotranspiration is estimated with the Hargreaves equation using minimum and maximum air temperatures from the downscaled GCM data. These simulated 2050–2055 river flows are input to a water budget formulation for the Lago Loíza reservoir for comparison with 2007–2012. The ANN scenarios require far less computational effort than a numerical model application, yet produce results with sufficient accuracy to evaluate and compare hydrologic scenarios. This hydrologic tool will be useful for future evaluations of the Lago Loíza reservoir and water supply to the San Juan metropolitan area.

Puerto Rico↗
USGS2018

Changing station coverage impacts temperature trends in the Upper Colorado River Basin

Over the Upper Colorado River Basin (UCRB), temperatures in widely used gridded data products do not warm as much as mean temperatures from a stable set of U.S. Historical Climatology Network (USHCN) stations, located at generally lower elevations, in most months of the year. This is contrary to expectations of elevation-dependent warming, which suggests that warming increases with elevation. These findings could reflect 1) a genuine absence of elevation-dependent warming in the region, 2) systematic non-climatic influences on either the USHCN stations or high elevation stations, including known inhomogeneities related to changes in the time of observation and instrumentation, or 3) suppression of an elevation-dependent warming signal introduced by changes in the station network. While we cannot categorically dismiss the first two possibilities, we show here that over portions of the 20th century, gridded temperatures warm less than USHCN temperatures and the difference cannot be explained by accounting for known inhomogeneities. These analyses suggest that changing station coverage in the UCRB has influenced trends in gridded temperature estimates that incorporate changing suites of stations over time. Specifically, increases in the number of high-elevation stations in the UCRB may have led to an underestimation of elevation-dependent warming, particularly during the spring and summer. This phenomenon is unlikely limited to this specific basin, and may be present in other high-elevation watersheds across the western U.S.

Upper Colorado River Basin↗
USGS2024

Evaluating water-quality trends in agricultural watersheds prioritized for management-practice implementation

Many agricultural watersheds rely on the voluntary use of management practices (MPs) to reduce nonpoint source nutrient and sediment loads; however, the water-quality effects of MPs are uncertain. We interpreted water-quality responses from as early as 1985 through 2020 in three agricultural Chesapeake Bay watersheds that were prioritized for MP implementation, namely, the Smith Creek (Virginia), Upper Chester River (Maryland), and Conewago Creek (Pennsylvania) watersheds. We synthesized patterns in MPs, climate, land use, and nutrient inputs to better understand factors affecting nutrient and sediment loads. Relations between MPs and expected water-quality improvements were not consistently identifiable. The number of MPs increased in all watersheds since the early 2010s, but most monitored nutrient and sediment loads did not decrease. Nutrient and sediment loads increased or remained stable in Smith Creek and the Upper Chester River. Sediment loads and some nutrient loads decreased in Conewago Creek. In Smith Creek, a 36-year time-series model suggests that changes in manure affected flow-normalized total nitrogen loads. We hypothesize that increases in nutrient applications may overshadow some expected MP effects. MPs might have stemmed further water-quality degradation, but improvements in nutrient loads may rely on reducing manure and fertilizer applications. Our results highlight the importance of assessing MP performance with long-term monitoring-based studies.

Journal of the American Water Resources Assocation↗
USGS2018

Filtering of periodic infiltration in a layered vadose zone: 2. Applications and a freeware screening tool

We have developed a screening tool to visualize and conceptualize the filtering properties of a layered vadose zone. Climate projections indicate that rainfall timing and magnitude may change and impact groundwater resources. This increases the importance of understanding how the vadose zone filters infiltration variability and ultimately affects recharge and groundwater resources. An approximate solution for the filtering of surface forcings through soil layers was developed previously, and the soil and conditions where its approximations are appropriate was evaluated. Here we present a screening tool based on the solution for estimating how periodic infiltration forcings filter in a layered vadose zone for different soil properties and surface flux conditions. The solutions identify time-varying elements of surface forcings that persist to the depth of the water table, leading to transient recharge. We investigated the filtering properties of the vadose zone in Central Valley, California, and identified areas where surface forcings are essentially damped and recharge can be approximated as steady. We also determined the travel time for infiltration pulses to reach the depth of the water table.

Vadose Zone Journal↗
USGS2017

Physical properties of the WAIS Divide ice core

The WAIS (West Antarctic Ice Sheet) Divide deep ice core was recently completed to a total depth of 3405 m, ending ∼50 m above the bed. Investigation of the visual stratigraphy and grain characteristics indicates that the ice column at the drilling location is undisturbed by any large-scale overturning or discontinuity. The climate record developed from this core is therefore likely to be continuous and robust. Measured grain-growth rates, recrystallization characteristics, and grain-size response at climate transitions fit within current understanding. Significant impurity control on grain size is indicated from correlation analysis between impurity loading and grain size. Bubble-number densities and bubble sizes and shapes are presented through the full extent of the bubbly ice. Where bubble elongation is observed, the direction of elongation is preferentially parallel to the trace of the basal (0001) plane. Preferred crystallographic orientation of grains is present in the shallowest samples measured, and increases with depth, progressing to a vertical-girdle pattern that tightens to a vertical single-maximum fabric. This single-maximum fabric switches into multiple maxima as the grain size increases rapidly in the deepest, warmest ice. A strong dependence of the fabric on the impurity-mediated grain size is apparent in the deepest samples.

Journal of Glaciology↗
USGS2012

A national geographic framework for guiding conservation on a landscape scale

The U.S. Fish and Wildlife Service, along with the global conservation community, has recognized that the conservation challenges of the 21st century far exceed the responsibilities and footprint of any individual agency or program. The ecological effects of climate change and other anthropogenic stressors do not recognize geopolitical boundaries and, as such, demand a national geographic framework to provide structure for cross-jurisdictional and landscape-scale conservation strategies. In 2009, a new map of ecologically based conservation regions in which to organize capacity and implement strategic habitat conservation was developed using rapid prototyping and expert elicitation by an interagency team of U.S. Fish and Wildlife Service and U.S. Geological Survey scientists and conservation professionals. Incorporating Bird Conservation Regions, Freshwater Ecoregions, and U.S. Geological Survey hydrologic unit codes, the new geographic framework provides a spatial template for building conservation capacity and focusing biological planning and conservation design efforts. The Department of Interior's Landscape Conservation Cooperatives are being organized in these new conservation regions as multi-stakeholder collaborations for improved conservation science and management.

Journal of Fish and Wildlife Management↗
USGS1985

Maceral distributions in Illinois coals and their paleoenvironmental implications

For purposes of assessing the maceral distribution of Illinois (U.S.A.) coals analyses were assembled for 326 face channel and drill core samples from 24 coal members of the Pennsylvanian System. The inertinite content of coals from the Missourian and Virgilian Series averages 16.1% (mineral free), compared to 9.4% for older coals from the Desmoinesian and older Series. This indicates there was generally a higher state of oxidation in the peat that formed the younger coals. This state probably resulted from greater exposure of these peats to weathering as the climate became drier and the water table lower than was the case for the older coals, although oxidation during allochthonous deposition of inertinite components is a genetic factor that needs further study to confirm the importance of the climate. Regional variation of the vitrinite-inertinite ratio (V-I), on a mineral- and micrinite-free basis, was observed in the Springfield (No. 5) and Herrin (No. 6) Coal Members to be related to the geographical position of paleochannel (river) deposits known to have been contemporaneous with the peats that formed these two coal strata. The V-I ratio is highest (generally 12–27) in samples from areas adjacent to the channels, and lower (5–11) some 10–20 km away. We interpret the V-I ratio to be an inverse index of the degree of oxidation to which the original peat was exposed. High V-I ratio coal located near the channels probably formed under more anoxic conditions than did the lower V-I ratio coal some distance away from the channels. The low V-I ratio coal probably formed in areas of the peat swamp where the watertable was generally lower than the channel areas.

International Journal of Coal Geology↗
USGS1996

Southern Ocean monthly wave fields for austral winters 1985-1988 by Geosat radar altimeter

Four years of monthly averaged wave height fields for the austral winters 1985–1988 derived from the Geosat altimeter data show a spatial variability of the scale of 500–1000 km that varies monthly and annually. This variability is superimposed on the zonal patterns surrounding the Antarctic continent and characteristic of the climatology derived from the U.S. Navy [1992] Marine Climatic Atlas of the World. The location and the intensity of these large-scale features, which are not found in the climatological fields, exhibit strong monthly and yearly variations. A global underestimation of the climatological mean wave heights by more than 1 m is also found over large regions of the Southern Ocean. The largest monthly averaged significant wave heights are above 5 m and are found during August of every year in the Indian Ocean, south of 40°S. The monthly wave fields show more variability in the Atlantic and Pacific Oceans than in the Indian Ocean. The Seasat data from 1978 and the Geosat data from 1985 and 1988 show an eastward rotation of the largest wave heights. However, this rotation is absent in 1986 and 1987; the former was a year of unusually low sea states, and the latter was a year of unusually high sea states, which suggests a link to the El Niño-Southern Oscillation event of 1986.

Journal of Geophysical Research C: Oceans↗
USGS2017

Salinity influences on aboveground and belowground net primary productivity in tidal wetlands

Tidal freshwater wetlands are one of the most vulnerable ecosystems to climate change and rising sea levels. However salinification within these systems is poorly understood, therefore, productivity (litterfall, woody biomass, and fine roots) were investigated on three forested tidal wetlands [(1) freshwater, (2) moderately saline, and (3) heavily salt-impacted] and a marsh along the Waccamaw and Turkey Creek in South Carolina. Mean aboveground (litterfall and woody biomass) production on the freshwater, moderately saline, heavily salt-impacted, and marsh, respectively, was 1,061, 492, 79, and 0     g   m − 2   year − 1 versus belowground (fine roots) 860, 490, 620, and 2,128     g   m − 2   year − 1 . Litterfall and woody biomass displayed an inverse relationship with salinity. Shifts in productivity across saline sites is of concern because sea level is predicted to continue rising. Results from the research reported in this paper provide baseline data upon which coupled hydrologic/wetland models can be created to quantify future changes in tidal forest functions.

South Carolina↗
USGS2003

Late Pleistocene to Holocene slip rates for the Gurvan Bulag thrust fault (Gobi-Altay, Mongolia) estimated with 10Be dates

We surveyed morphotectonic markers along the central part of the Gurvan Bulag thrust, a fault that ruptured with the Bogd fault during the Gobi-Altay earthquake (1957, M 8.3), to document climatic and tectonic processes along the fault for the late Pleistocene- Holocene period. The markers were dated using 10Be produced in situ. Two major periods of alluviation ended at 131 ?? 20 and 16 ?? 4.8 ka. These appear to be contemporaneous with global climatic changes at the terminations of marine isotope stages (MIS) 6 and 2. The vertical slip rates, determined from offset measurements and surfaces ages, are 0.14 ?? 0.03 mm/yr over the late Pleistocene-Holocene and between 0.44 ?? 0.11 and 1.05 ?? 0.25 mm/yr since the end of the late Pleistocene. The higher of these slip rates for the last ???16 kyr is consistent with paleoseismic investigations along the fault [Prentice et al., 2002], and suggests that, at the end of late Pleistocene, the fault evolved from quiescence to having recurrence intervals of 4.0 ?? 1.2 kyr for surface ruptures with ???4 m vertical offset (similar to that of 1957). The inferred recurrence interval is comparable to that of the Bogd fault (3.7 ?? 1.3 kyr) suggesting that the two faults may have ruptured together also earlier during the last ???16 kyr.

Journal of Geophysical Research B: Solid Earth↗
USGS2018

A review of coastal management approaches to support the integration of ecological and human community planning for climate change

The resilience of socio-ecological systems to sea level rise, storms and flooding can be enhanced when coastal habitats are used as natural infrastructure. Grey infrastructure has long been used for coastal flood protection but can lead to unintended negative impacts. Natural infrastructure often provides similar services as well as added benefits that support short- and long-term biological, cultural, social, and economic goals. While natural infrastructure is becoming more widespread in practice, it often represents a relatively small fraction within portfolios of coastal risk-reducing strategies compared to more traditional grey infrastructure. This study provides a comprehensive review of how natural infrastructure is being used along the United States Atlantic, Gulf of Mexico, and Caribbean coasts related to four habitats – tidal marshes, beaches and barrier islands, mangroves, and biogenic reefs. We compare information on the benefits, opportunities and challenges of implementing natural, grey and hybrid infrastructure in the coastal zone. In addition, we present a suite of actions to increase information and reduce uncertainty so that coastal mangers and planners are aware of the full suite of options for restoration, conservation and planning that maximize ecosystem services over short- and long-term planning horizons.

Journal of Coastal Conservation↗
USGS2013

Floral ecology and insect visitation in riparian Tamarix sp. (saltcedar)

Climate change projections for semiarid and arid North America include reductions in stream discharge that could adversely affect riparian plant species dependent on stream-derived ground water. In order to better understand this potential impact, we used a space-for-time substitution to test the hypotheses that increasing depth-to-groundwater (DGW) is inversely related to Tamarix sp. (saltcedar) flower abundance (F) and nectar production per flower (N). We also assessed whether DGW affected the richness or abundance of insects visiting flowers. We examined Tamarix floral attributes and insect visitation patterns during 2010 and 2011 at three locations along a deep DWG gradient (3.2–4.1 m) on a floodplain terrace adjacent to Las Vegas Wash, an effluent-dominated Mojave Desert stream. Flower abundance and insect visitation patterns differed between years, but no effect from DGW on either F or N was detected. An eruption of a novel non-native herbivore, the splendid tamarisk weevil (Coniatus splendidulus), likely reduced flower production in 2011.

Journal of Arid Environments↗
USGS2001

El Niño and its impact on fire weather conditions in Alaska

Examining the relationship of El Niño to weather patterns in Alaska shows wide climate variances that depend on the teleconnection between the tropics and the northern latitudes. However, the weather patterns exhibited in Alaska during and just after moderate to strong El Niño episodes are generally consistent: above normal temperature and precipitation along the Alaskan coast, and above normal temperature and below normal precipitation in the interior, especially through the winter. The warm, dry conditions in the Alaskan interior increase summer wildfire potential. Statistics on the area burned since 1940 show that 15 out of 17 of the biggest fire years occurred during a moderate to strong El Niño episode. These 15 years account for nearly 63% of the total area burned over the last 58 years. Evidence points to increased dry thunderstorms and associated lightning activity during an El Niño episode; the percentage of total area burned by lightning caused fires during five episodes increased from a normal of less than 40% to a high of about 96%.

International Journal of Wildland Fire↗
USGS2010

Rapid climatic signal propagation from source to sink in a southern California sediment-routing system

Terrestrial source areas are linked to deep-sea basins by sediment-routing systems, which only recently have been studied with a holistic approach focused on terrestrial and submarine components and their interactions. Here we compare an extensive piston-core and radiocarbon-age data set from offshore southern California to contemporaneous Holocene climate proxies in order to test the hypothesis that climatic signals are rapidly propagated from source to sink in a spatially restricted sediment-routing system that includes the Santa Ana River drainage basin and the Newport deep-sea depositional system. Sediment cores demonstrate that variability in rates of Holocene deep-sea turbidite deposition is related to complex ocean-atmosphere interactions, including enhanced magnitude and frequency of the North American monsoon and El Ni??o-Southern Oscillation cycles, which increased precipitation and fluvial discharge in southern California. This relationship is evident because, unlike many sediment-routing systems, the Newport submarine canyon-and-channel system was consistently linked tothe Santa Ana River,which maintained sediment delivery even during Holocene marine transgression and highstand. Results of this study demonstrate the efficiency of sediment transport and delivery through a spatially restricted, consistently linked routing system and the potential utility of deep-sea turbidite depositional trends as paleoclimate proxies in such settings. ?? 2010 by The University of Chicago.

Journal of Geology↗