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USGS2005

Residues of toxaphene in insectivorous birds ( Petrochelidon spp.) from the Rio Grande, Texas

Although it has been documented that wildlife in the Rio Grande Valley (RGV) contain increased concentrations of organochlorine (OC) contaminants, particularly DDE, little has been published on residues of toxaphene throughout this major North American watershed. In this study, 28 liver composites from adult swallows ( Petrochelidon spp.) collected along the Rio Grande from 1999 through 2000 were analyzed for toxaphene residues using congener-specific gas chromatography–electron-capture negative ionization–mass spectrometry. Estimated total toxaphene concentrations ranged from 12 to 260 ng/g wet wt and were highest in samples from the lower RGV near Llano Grande Lake in Hidalgo and Cameron counties (Texas). Toxaphene congener profiles were relatively invariant throughout the watershed and were dominated by 2,2,5-endo,6-exo,8,8,9,10-octachlorobornane (P-42a or B8-806) with lesser amounts of several other Cl 7 -Cl 9 compounds, many of which remain unidentified. Petrochelidon spp. liver profiles appear to be intermediate in complexity between those in invertebrates and fish (more complex) and mammals (less complex) and differs somewhat from those reported for other avian species. In addition to other legacy OC contaminants, toxaphene residues were most concentrated in the lower RGV and accumulated at up to hundreds of parts per billion in these insect-eating birds, underscoring their utility as avian bioindicators of persistent organic pollutants.

Archives of Environmental Contamination and Toxico↗

USGS2025

A nationwide evaluation of crowd-sourced ambient temperature data

Growing concerns about heat in urban areas paired with the sparsity of weather stations have resulted in individuals drawing on data from citizen science sensor networks to fill in data gaps. The PurpleAir are the most widely-used low-cost air quality sensors in the contiguous United States with 14,777 deployed between 1 Jan 2017 and 20 July 2021. Although the air quality data from PurpleAir sensors have been widely studied, less attention has been paid to reported temperature. We compare temperature metrics reported by PurpleAir sensors with a gridded temperature product, the North American Land Data Assimilation System (NLDAS)-2, which although not a gold-standard measure of temperature, is widely used in epidemiologic research. We evaluate the lag between indoor and outdoor PurpleAir temperatures. We report associations of the difference between outdoor PurpleAir temperatures and NLDAS-2 temperatures, an indicator of degradation, and the duration of sensor operation. Finally, based on the temperature range recorded by the outdoor PurpleAir sensors vis.a.vis NLDAS-2 temperatures, we provide a list of 271 (2.5%) sensors potentially misclassified as outdoor and likely located indoors. We observed that outdoor PurpleAir sensors agreed well with NLDAS-2 (R2 > 0.82). This association broke down under warm conditions (daily average NLDAS ≥ 21.1oC). Landcover and climate zone were significant modifiers of the association between PurpleAir and NLDAS-2 temperature metrics with the poorest PurpleAir- NLDAS-2 agreement in urban areas. Indoor PurpleAir temperatures lagged hourly NLDAS temperatures by two hours across almost all climate zones. The mean difference in hourly PurpleAir and NLDAS-2 temperatures increased by 0.57oC for every operational year, suggesting that careful attention must be paid to degradation. Overall, we find for use in epidemiological studies, that the PurpleAir sensor data is a reliable metric of daytime mean air temperature, but researchers should be aware of its limitations when examining extreme heat, or when aggregating sensor data across multiple years.

Frontiers of Environmental Science and Engineering↗

USGS2007

Mercury and organic carbon dynamics during runoff episodes from a northeastern USA watershed

Mercury and organic carbon concentrations vary dynamically in streamwater at the Sleepers River Research Watershed in Vermont, USA. Total mercury (THg) concentrations ranged from 0.53 to 93.8 ng/L during a 3-year period of study. The highest mercury (Hg) concentrations occurred slightly before peak flows and were associated with the highest organic carbon (OC) concentrations. Dissolved Hg (DHg) was the dominant form in the upland catchments; particulate Hg (PHg) dominated in the lowland catchments. The concentration of hydrophobic acid (HPOA), the major component of dissolved organic carbon (DOC), explained 41–98% of the variability of DHg concentration while DOC flux explained 68–85% of the variability in DHg flux, indicating both quality and quantity of the DOC substantially influenced the transport and fate of DHg. Particulate organic carbon (POC) concentrations explained 50% of the PHg variability, indicating that POC is an important transport mechanism for PHg. Despite available sources of DHg and wetlands in the upland catchments, dissolved methylmercury (DmeHg) concentrations in streamwaters were below detection limit (0.04 ng/L). PHg and particulate methylmercury (PmeHg) had a strong positive correlation ( r 2 = 0.84, p < 0.0001), suggesting a common source; likely in-stream or near-stream POC eroded or re-suspended during spring snowmelt and summer storms. Ratios of PmeHg to THg were low and fairly constant despite an apparent higher methylmercury (meHg) production potential in the summer. Methylmercury production in soils and stream sediments was below detection during snowmelt in April and highest in stream sediments (compared to forest and wetland soils) sampled in July. Using the watershed approach, the correlation of the percent of wetland cover to TmeHg concentrations in streamwater indicates that poorly drained wetland soils are a source of meHg and the relatively high concentrations found in stream surface sediments in July indicate these zones are a meHg sink.

Water, Air, & Soil Pollution↗

USGS2008

PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors

The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p?-DDE (DDE) from 2,350 to 1,353 to 210 ??g/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., ???PCBs 688 to 245 to 182 ??g/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 ??g/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern pikeminnow (Ptychocheilus oregonensis), which account for about 90% of the biomass in the diet of this osprey population, were also collected from the Willamette River in 1993 and 2001 and analyzed for the same contaminants as osprey eggs. Contaminant residues in fish from the Upper River decreased between 1993 and 2001, paralleling findings for osprey eggs. Likewise, spatial patterns for fish residues paralleled findings for osprey eggs from the different reaches in 2001. A second empirical estimate of biomagnification factors (BMFs) from fish to osprey eggs for OC pesticides, PCBs, PCDDs and PCDFs (ww and lipid weight [lw] basis) was calculated based on residue data collected in 2001. The two independent BMF estimates (1993 and 2001) for each contaminant from the Upper River provide a measure of consistency, e.g., DDE (ww) 87 and 79, (lw) 103 and 112; ???PCBs (ww) 11 and 8.4, (lw) 13 and 12. Mercury did not biomagnify from fish to osprey eggs (BMF = 0.60). Legacy contaminants investigated had limited (perhaps only DDE), if any, effects on reproductive success of the increasing osprey population nesting along the Willamette River by 2001. ?? 2008 U.S. Government.

Ecotoxicology↗

USGS2021

Reply to comment by R. Parkinson on “Increasing rates of carbon burial in southwest Florida coastal wetlands” by J. Breithaupt et al.

Breithaupt et al. (2020) investigated why rates of organic carbon (OC) burial in coastal wetlands appear to increase over the past ∼120 years. After comparing dating methods and applying biogeochemical analyses, we concluded that neither dating method nor carbon degradation contribute to the observed trend. Rather, we concluded that OC burial has increased in the past century. Parkinson's (2021) Comment disagrees with our conclusion, contending that: 1) use of a density correction to account for soil auto‐compaction is a flawed methodology that artificially shortens a core's length, 2) there is limited evidence for an acceleration in the regional sea‐level rise (SLR) rate, and 3) vertical accretion rates in previous papers by Breithaupt et al. (2014, 2017) are lower than the regional mean rate of SLR and are not to be believed as these wetlands should have converted to open water by now. We reject these contentions because: 1) no density correction was applied to the cores in this study, 2) local tide gauge records and analyses in the literature support an increase in SLR rates coinciding with the timeframe of our OC burial records, and 3) Parkinson's comparison of the 100‐yr mean rate of SLR neglects temporal variability and uncertainties in the long‐term sea‐level record, as well as biophysical feedbacks between wetland surface elevation and SLR. Here, we provide detailed responses to Parkinson's contentions and establish the importance of differentiating operational definitions of OC burial and accretion to clarify why an auto‐compaction correction is not applicable for OC burial measurements.

Florida↗

USGS2000

Contaminants in ospreys from the Pacific Northwest: II. Organochlorine pesticides, polychlorinated biphenyls and mercury, 1991-1997

Eggs of ospreys ( Pandion haliaetus ) were collected over the period 1991 to 1997 at 111 nests in the Fraser and Columbia River drainage systems of British Columbia, Washington, and Oregon. Contents were analyzed for organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and total mercury. Blood samples were taken from nestling ospreys at two time points during the 1992 breeding season on the Thompson River and analyzed for non-ortho PCBs. Concentrations of DDE and related compounds showed high variability among individual eggs within study areas and no significant differences in mean concentrations among study areas. Some eggs contained high concentrations of DDE, up to 20 mg/kg (wet weight), for which there were no evident local sources, suggesting that exposure occurred outside of the breeding grounds. Most other OC pesticides measured in osprey eggs showed a similar distribution, although mean concentrations of chlordane-related compounds were generally, and in some cases significantly, higher in samples collected from the Columbia River sites compared to elsewhere. Significantly greater concentrations of PCBs were found in eggs from the Columbia River basin compared to the Fraser. This was attributed to extensive development of hydroelectric generation and related industries on the Columbia system. Significant differences among sites were also found in the pattern of PCB congeners, e.g., eggs from the lower Columbia River site had proportionally greater concentrations of less chlorinated, Aroclor 1242–type PCBs compared to other sites. In contrast, eggs from upper reaches of the Columbia River had relatively greater amounts of Aroclor 1254 and 1260 congeners. Mercury concentrations in osprey eggs tended to be uniform among sites and comparable to those reported in the literature for ospreys nesting on naturally formed lakes and rivers. There were no significant temporal changes in mean concentrations of any of the measured compounds at sites monitored from 1991 to 1997.

Archives of Environmental Contamination and Toxico↗

USGS2012

An initial investigation into the organic matter biogeochemistry of the Congo River

The Congo River, which drains pristine tropical forest and savannah and is the second largest exporter of terrestrial carbon to the ocean, was sampled in early 2008 to investigate organic matter (OM) dynamics in this historically understudied river basin. We examined the elemental (%OC, %N, C:N), isotopic (δ 13 C, Δ 14 C, δ 15 N) and biochemical composition (lignin phenols) of coarse particulate (>63 μm; CPOM) and fine particulate (0.7–63 μm; FPOM) OM and DOC, δ 13 C, Δ 14 C and lignin phenol composition with respect to dissolved OM (<0.7 μm; DOM) from five sites in the Congo River Basin. At all sample locations the organic carbon load was dominated by the dissolved phase (~82–89% of total organic carbon) and the total suspended sediment load was principally fine particulate material (~81–91% fine suspended sediment). Distinct compositional and isotopic differences were observed between all fractions. Congo CPOM, FPOM and DOM all originated from vegetation and soil inputs as evidenced by elemental, isotopic and lignin phenol data, however FPOM was derived from much older carbon pools (mean Δ 14 C = -62.2 ± -13.2&permil;, n = 5) compared to CPOM and DOM (mean Δ 14 C = 55.7 ± 30.6&permil;, n = 4 and 73.4 ± 16.1&permil;, n = 5 respectively). The modern radiocarbon ages for DOM belie a degraded lignin compositional signature (i.e. elevated acid:aldehyde ratios (Ad:Al) relative to CPOM and FPOM), and indicate that the application of OM degradation patterns derived from particulate phase studies to dissolved samples needs to be reassessed: these elevated ratios are likely attributable to fractionation processes during solubilization of plant material. The relatively low DOM carbon-normalized lignin yields (Λ8; 0.67–1.12 (mg(100 mg OC) -1 )) could also reflect fractionation processes, however, they have also been interpreted as an indication of significant microbial or algal sources of DOM. CPOM appears to be well preserved higher vascular plant material as evidenced by its modern radiocarbon age, elevated C:N (17.2–27.1) and Λ8 values (4.56–7.59 (mg(100 mg OC) -1 )). In relation to CPOM, the aged FPOM fraction (320–580 ybp 14 C ages) was comparatively degraded, as demonstrated by its nitrogen enrichment (C:N 11.4–14.3), lower Λ8 (2.80–4.31 (mg(100 mg OC) -1 )) and elevated lignin Ad:Al values similar to soil derived OM. In this study we observed little modification of the OM signature from sample sites near the cities of Brazzaville and Kinshasa to the head of the estuary (~350 km) highlighting the potential for future studies to assess seasonal and long-term OM dynamics from this logistically feasible location and derive relevant information with respect to OM exported to the Atlantic Ocean. The relative lack of OM data for the Congo River Basin highlights the importance of studies such as this for establishing baselines upon which to gauge future change.

Congo River↗

USGS2006

A survey of chemical constituents in National Fish Hatchery fish feed

Recent studies have demonstrated that various fish feeds contain significant concentrations of contaminants, many of which can bioaccumulate and bioconcentrate in fish. It appears that numerous organochlorine (OC) contaminants are present in the fish oils and fish meals used in feed manufacture, and some researchers speculate that all fish feeds contain measurable levels of some contaminants. To determine the presence and concentration of contaminants in feeds used in National Fish Hatcheries managed by the U.S. Fish & Wildlife Service, we systematically collected samples of feed from 11 hatcheries that raise cold-water species, and analyzed them for a suite of chemical contaminants. All of the samples (collected from October 2001 to October 2003) contained measurable concentrations of at least one dioxin, furan, polychlorinated biphenyl (PCB) congener, or dichlorodiphenyltrichloroethane (DDT) metabolite. All samples which were assayed for all contaminants contained one or more of those classes of compounds and most contained more than one; dioxin was detected in 39 of the 55 samples for which it was assayed, 24 of 55 contained furans and 24 of 55 samples contained DDT or its metabolites. There with 10- to 150-fold differences in the range in concentrations of the additive totals for PCBs, dioxins, furans and DDT. Although PCBs were the most commonly detected contaminant in our study (all samples in which it was assayed), the concentrations (range: 0.07 to 10.46 ng g·1 wet weight) were low compared to those reported previously. In general, we also found lower levels of organochlorine contaminants than have been reported previously in fish feed. Perhaps most notable is the near absence of OC pesticides~xcept for DDT (and its metabolites) and just two samples containing benzene hexachloride (Lindane). While contaminant concentrations were generally low, the ecological impacts can not be determined without a measure of the bioaccumulation of these compounds in the fish and the fate of these compounds after the fish are released from the hatcheries.

Report↗

USGS2000

Growth in conventional fields in high-cost areas: A case study

Exploration managers commonly base future drilling decisions on past experience in an area. To do this well, they should consider both discovered and undiscovered resources to characterize total future potential. Discovery-size estimates should be adjusted to account for future field growth; otherwise, the relative efficiency of recent exploration will be undervalued. This study models and projects field growth for pre-1997 discoveries in the U.S. Federal Gulf of Mexico (GOM) Outer Continental Shelf (OCS). Projected additions to reserves for these fields from field growth through 2020 are 5.2 billion bbl of oil and 46 Tcfg. Projections include growth associated with sizable new oil discoveries in deepwater areas and initial reserve additions from new subsalt plays discovered through 1996. This article focuses on the U.S. GOM because it has produced longer than other worldwide offshore areas. Its field-growth profile may be prototypical of other offshore provinces such as the North Sea, Scotian Shelf and deepwater Angola, as well as high-cost onshore areas.

Gulf Of Mexico↗

USGS2015

Determining the importance of model calibration for forecasting absolute/relative changes in streamflow from LULC and climate changes

Land use/land cover (LULC) and climate changes are important drivers of change in streamflow. Assessing the impact of LULC and climate changes on streamflow is typically done with a calibrated and validated watershed model. However, there is a debate on the degree of calibration required. The objective of this study was to quantify the variation in estimated relative and absolute changes in streamflow associated with LULC and climate changes with different calibration approaches. The Soil and Water Assessment Tool (SWAT) was applied in an uncalibrated (UC), single outlet calibrated (OC), and spatially-calibrated (SC) mode to compare the relative and absolute changes in streamflow at 14 gaging stations within the Santa Cruz River Watershed in southern Arizona, USA. For this purpose, the effect of 3 LULC, 3 precipitation (P), and 3 temperature (T) scenarios were tested individually. For the validation period, Percent Bias (PBIAS) values were >100% with the UC model for all gages, the values were between 0% and 100% with the OC model and within 20% with the SC model. Changes in streamflow predicted with the UC and OC models were compared with those of the SC model. This approach implicitly assumes that the SC model is “ideal”. Results indicated that the magnitude of both absolute and relative changes in streamflow due to LULC predicted with the UC and OC results were different than those of the SC model. The magnitude of absolute changes predicted with the UC and SC models due to climate change (both P and T) were also significantly different, but were not different for OC and SC models. Results clearly indicated that relative changes due to climate change predicted with the UC and OC were not significantly different than that predicted with the SC models. This result suggests that it is important to calibrate the model spatially to analyze the effect of LULC change but not as important for analyzing the relative change in streamflow due to climate change. This study also indicated that model calibration in not necessary to determine the direction of change in streamflow due to LULC and climate change.

Santa Cruz River Watershed↗

USGS1976

Report on the environmental geology OCS area, eastern Gulf of Alaska

In anticipation of oil and gas leasing of the outer continental shelf (OCS lease area 39) in the northeastern Gulf of Alaska, the U. S. Geological Survey began a regional reconnaissance in 1974. The study area, which extends from Prince William Sound on the west to Yakutat Bay on the east, is in a region fraught with natural hazards. The tectonic history of the area suggests that future major earthquakes could pose serious hazards to installations on the continental shelf or along the coast of the Gulf of Alaska. The hazard may be either direct, by ground shaking or fault displacement, or indirect, through ground failure or generation of tsunami waves. Storm waves sometimes are responsible for ground failures, especially in areas of rapid accumulation of sediment.

Alaska↗

USGS2006

Effects of contaminants on reproductive success of aquatic birds nesting at Edwards Air Force Base, California

Contamination by organochlorine pesticides (OCs), polychlorinated biphenyls, metals, and trace elements at Edwards Air Force Base (EAFB), located in the Mojave Desert, could adversely affect nesting aquatic birds, especially at the sewage lagoons that comprise Piute Ponds. Estimates of avian reproduction, in conjunction with analyses of eggs and avian foods for contaminant residues, may indicate the potential for negative effects on avian populations. From 1996 to 1999, we conducted studies at the Piute Ponds area of EAFB to evaluate the impacts of contaminants on nesting birds. Avian reproduction was evaluated in 1999. Eggs were collected for chemical analyses in 1996 and 1999, and African clawed frogs (Xenopus laevis), a likely food source, were collected for chemical analyses in 1998. Avian species occupying the higher trophic levels-black-crowned night-heron (Nycticorax nycticorax), white-faced ibis (Plegadis chihi), and American avocet (Recurvirostra americana)-generally bioaccumulated higher concentrations of contaminants in their eggs. Reproductive success and egg hatchability of night-herons and white-faced ibises in the Piute Ponds were similar to results observed at other western colonies. Deformities were observed in only one embryo in this study, but concentrations of contaminants evaluated in this ibis embryo were considered insufficient to have caused the deformities. Because clawed frogs, a primary prey item for night-herons at Piute Ponds, had no detectable levels of any OCs, it is likely that OCs found in night-heron eggs were acquired from the wintering grounds rather than from EAFB. The presence of isomers of dichlorodiphenyltrichloroethane (DDT) in ibis eggs indicated recent exposure, but invertebrates used for food by ibises were not sampled at Piute Ponds, and conclusions about the source of OCs in ibis eggs could not be made. Concentrations of contaminants in random and failed eggs of individual species were not different, and we concluded that contaminants did not cause the observed egg failures. ?? 2006 Springer Science+Business Media, Inc.

Archives of Environmental Contamination and Toxico↗

USGS1995

Evaluation of lipid-containing semipermeable membrane devices for monitoring organochlorine contaminants in the Upper Mississippi river

Organochlorine contaminants sequestered in lipid-containing semipermeable membrane devices (SPMDs) were compared to those found in tangential-flow ultrafilter permeates as part of a pilot study at 10 sites in the Upper Mississippi River system. Caged and feral fish from three primary sites were also analyzed for comparison. Concentrated organochlorine (OC) compounds were readily extracted from the SPMDs by dialysis into hexane, and samples were analyzed by gas chromatography-negative chemical ionization-mass spectrometry. Fish and water samples were processed by conventional methods. Reasonable agreement was found between analyte SPMD-derived water concentrations and measured values of ultrafilter permeates; however, concentrations of the same analytes in caged fish did not appear to be proportional to water concentrations derived from SPMDs and ultrafilter permeates. The greatest number of OC compounds was detected in SPMDs; fewer were detected in caged fish and feral fish.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗

USGS1978

Estimated oil and gas reserves, Southern California Outer Continental Shelf, January 1, 1977

As of January 1, 1977, approximately 1,450 billion cubic feet of gas and about 670 million barrels of oil* are estimated as remaining recoverable reserves in 11 of the 12 fields in the Outer Continental Shelf (OCS) off Southern California. No estimates were made for the unnamed field on lease P-0234 because well testing was not sufficient to allow a reasonable assessment. Of the 12 recognized fields, only two are producing and none is completely developed. Limits of many of the fields will be further defined by anticipated additional exploratory drilling. Original recoverable reserves in 11 fields are estimated to have been approximately 1,530 billion cubic feet of gas and about 830 million barrels of oil. Reserve estimates for nine fields were based on individual volumetric reservoir studies. Decline curve and volumetric analyses were used to estimate reserves in two fields. The estimates of original and remaining reserves are reported as one total for oil and one for gas within the Southern California OCS. *The term "oil" as used in this report includes crude oil, condensate and gas-plant liquids.

California↗

USGS2016

Novel insights from NMR spectroscopy into seasonal changes in the composition of dissolved organic matter exported to the Bering Sea by the Yukon River

Seasonal (spring freshet, summer–autumn, and winter) variability in the chemical composition of dissolved organic matter (DOM) from the Yukon River was determined using advanced one- and two-dimensional (2D) solid-state NMR spectroscopy, coupled with isotopic measurements and UV–visible spectroscopy. Analyses were performed on two major DOM fractions, the hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions obtained using XAD resins. Together these two fractions comprised 64–74% of the total DOM. Carboxyl-rich alicyclic molecules (CRAM) accounted for the majority of carbon atoms in the HPOA (63–77%) and TPIA (54–78%) samples, and more so in winter and summer than in spring samples. 2D and selective NMR data revealed association of abundant nonprotonated O-alkyl and quaternary alkyl C (OC np , OC np O and C q , 13–17% of HPOA and 15–20% of TPIA) and isolated O–CH structures with CRAM, which were not recognized in previous studies. Spectral editing and 2D NMR allowed for the discrimination of carbohydrate-like O-alkyl C from non-carbohydrate O-alkyl C. Whereas two spring freshet TPIA samples contained carbohydrate clusters such as carboxylated carbohydrates (16% and 26%), TPIA samples from other seasons or HPOA samples mostly had small amounts (<8%) of sugar rings dispersed in a nonpolar alkyl environment. Though nonprotonated aromatic C represented the largest fraction of aromatic C in all HPOA/TPIA isolates, only a small fraction (&sim;5% in HPOA and 3% in TPIA) was possibly associated with dissolved black carbon. Our results imply a relatively stable portion of DOM exported by the Yukon River across different seasons, due to the predominance of CRAM and their associated nonprotonated C–O and O–C–O structures, and elevated reactivity (bio- and photo-lability) of spring DOM due to the presence of terrestrial inputs enriched in carbohydrates and aromatic structures.

Alaska, Yukon↗

USGS1976

A summary of petroleum potential, environmental geology, and the technology, time frame, and infrastructure for exploration and development of the western Gulf of Alaska

This summary of the regional geology, petroleum potential, geologic hazards and time frame for exploration of the western Gulf of Alaska has been written to aid the Bureau of Land Management in preparing the Draft Environmental Impact Statement. A preliminary version was written in Sept., 1975.(von Huene and others, 1975) in support of the Call for Nominations, Proposed OCS Oil and Gas Lease Sale #46. Since that time, there has been a substantial increase in information as the result of a two-month examination of recent studies of the adjacent Gulf of Alaska Tertiary Province and a preliminary interpretation of some publicly available common depth point (CDP) seismic reflection data recently acquired by the U.S. Geological Survey. The main source of geologic and geophysical data used in the preparation of this summary is published and unpublished information of the U.S. Geological Survey (Plafker and others, 1975,Bruns and Plafker, 1975; Carlson, Bruns and Molnia, 1975; Carlson and Molnia, 1975; Core, Mattick, and Bayer, 1975; Molnia and Carlson, 1975 a & b; von Huene and others, 1975). Prior to 1975, data were gathered mainly for purposes other than for assessment of oil and gas resources and of the environmental consequences of exploration and development. A systematic survey for such an assessment is planned for the summer of 1976 and, therefore, this summary is tentative. Although the major problems and regional setting are discussed in this paper, a great deal more specific data and interpretations will begin to become available in about one year. In this summary we consider the geology of a broad region on the continental shelf off the Kodiak group of islands and the Kenai Peninsula. We will concentrate on the area proposed for leasing in Sale #46. The area lies between about 56°N latitude and 60°N latitude (Fig. 1), and it measures approximately 660 km x 100 km. Water depths are generally less than 200 m.

Alaska↗

USGS2021

Effect of an algal amendment on the microbial conversion of coal to methane at different sulfate concentrations from the Powder River Basin, USA

Biogenic methane is estimated to account for one-fifth of the natural gas worldwide and there is great interest in controlling methane from different sources. Biogenic coalbed methane (CBM) production relies on syntrophic associations between fermentative bacteria and methanogenic archaea to anaerobically degrade recalcitrant coal and produce methanogenic substrates. However, very little is known about how differences in geochemistry, hydrology, and microbial community composition influence subsurface carbon utilization and CBM production. The addition of an amendment consisting of microalgal biomass has previously been shown to increase CBM production while providing the possibility of a closed-loop fossil system where waste (production water) is used to grow algae to ultimately produce energy (methane). However, the efficiency of enhancing CBM production under different redox conditions remains unresolved. In this study, we focused on the U.S. Geological Survey's Birney test site (Montana, USA) that has nine wells vertically accessing four coal seams with varying geochemistry (low and high sulfate (SO 4 2− )) and methane production rates. We used organic matter (OM) in the form of algal biomass to discern the effect of this amendment on OM degradation and microbially enhanced CBM production potential under different geochemical constraints. We tracked changes in community composition, OM composition, organic carbon (OC) concentration, methane production, and nutrients in batch systems over six months. Methane production was detected only in microcosms from low SO 4 2− wells (168 to 800 μg methane per gram of coal). The OC consumption varied across time for all wells and the variation was greatest for the low SO 4 2− wells. Different groups of syntrophic bacteria were associated with net‑carbon consuming microcosms, and specifically Syntrophorhabdus was identified with several different statistical methods as a potentially important coal degrader. Results from this study provide insight into potential coal-degraders, the compositional changes in some of the different OM fractions, and trends in carbon consumption related to methane production across coal seams along the vertical SO 4 2− gradient.

Montana, Wyoming↗

USGS1980

A summary of environmental geologic studies in the Georges Bank area, United States northeastern Atlantic Outer Continental Shelf, 1975-1977

The growing need for the United States to find and develop new energy resources has led to interest in the petroleum potential of frontier areas of the Atlantic Outer Continental Shelf (OCS) seaward of the eastern seaboard state boundaries. These submerged lands are under federal jurisdiction. The authority to lease tracts for resource development is vested with the Bureau of Land Management (BLM), of the Department of Interior, pursuant to the terms of the Outer Continental Shelf Lands Act of 1953 and the National Environmental Policy Act of 1969; the latter Act requires that the inevitable social and environmental effects of development be considered in leasing decisions. The Georges Bank region, part of the Continental Shelf off New England, is one of three designated Atlantic OCS target areas for petroleum exploration. It is also one of the world's most productive fishing grounds, and the nearby coastal states have high population densities, important fishing industries, and coastlines with extraordinary recreational and scenic value.

Georges Bank area↗