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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 901 records · Page 50Linked to original sources
USGS1983

An evaluation of trends in the acidity of precipitation and the related acidification of surface water in North America

The acidity of precipitation in the Northeastern United States and Southeastern Canada has increased in the past, probably as a result of anthropogenic emissions. The increase in New England and New York occurred primarily before the mid-1950's. Since the mid1960's, there has been no significant change in the acidity of precipitation in this region; however, sulfate concentrations have decreased and nitrate concentrations may have increased. The time of initial acidification in Southeastern Canada is not known because of a lack of historical data. In the Southeastern United States, the evaluation of whether precipitation has been acidified is complicated by meager data. The available data show that precipitation is more acidic than would be expected for sites unaffected by anthropogenic emissions. In addition, comparison of recent data with the meager historical data suggests, but does not unambiguously prove, increased acidification since the 1950's. In the Western United States, available data indicate that precipitation at individual sites has been acidified by anthropogenic emissions. The acidification generally has been attributable to localized sources, and the time of initial acidification is undefined. Acidification of lakes and streams in the Northeastern United States has occurred in a time frame compatible with the hypothesis that acidification of precipitation was the cause. The acidification of surface waters appears to have occurred before the mid- to late 1960's. In Southeastern Canada, the best-documented cases of acidified lakes point to localized sources of acidic emissions as the cause. Sparse evidence of recent regional acidification of lakes and streams exists, but evidence for acidification of precipitation as the cause is largely lacking. In the Southeastern United States, most data on acidification of surface waters are ambiguous, and in the West, most of the data reflect local conditions. However, recent analysis of a national network of remote stream sampling stations indicates that, since the mid- to late 1960's, sulfate concentrations have increased in the Southeast and the West, with a concurrent decrease in alkalinity. Additional work is needed to test the hypothesis that regional acidification of surface waters is occurring in the Southeastern and Western United States.

Water Supply Paper↗
USGS1993

Isolates of viral hemorrhagic septicemia virus from North America and Europe can be detected and distinguished by DNA probes

Biotinylated DNA probes were constructed to hybndize with speclfic sequences within the messenger RNA (mRNA) of the nucleoprotein (N) gene of vlral hemorrhagic septicemia virus (VHSV) reference strains from Europe (07-71) and North Arnenca (Makah) Probes were synthesized that were complementary to (1) a 29-nucleotide sequence near the center of the N gene conlmon to both the 07-71 and Makah reference strains of the virus (2) a unique 28- nucleotide sequence that followed the open readng frame of the Makah N gene mRNA most of which was absent In the 07-71 strain, and (3) a 22-nucleobde sequence wthin the 07-71 N gene that had 6 nllsmatches \nth the Makah straln Sixteen dlverse isolates of VHSV from North Amenca and Europe were tested by dot blot hybridization The first probe reacted with all isolates of the virus the second probe reacted with only the North Amencan isolates (includng those from Pacific cod), and the third probe reacted with only the European isolates, Including those from rainbow trout brown trout and Atlantic cod The probes did not react with mRNA extracted from uninfected cells or from cells infected with infectious hematopoletic necrosls vlrus (IHNV) a related fish rhabdovlrus The results showed that VHSV isolates from North Amenca and Europe formed 2 genetically distlnct strains of the virus in which isolates from different years or species of flsh on each continent were more related to each other than to isolates from the other continent The results of this and other studies indicate that the North Amencan straln of VHSV is enzootic in the North Pacific Ocean and IS not a result of a recent importation of fish from Europe When used In conlunchon with a biotinylated probe that recognizes all isolates of IHNV, these reagents promse to slrnphfy the detechon of salmonid rhabdoviruses

Diseases of Aquatic Organisms↗
USGS1993

Genetic comparison of viral hemorrhagic septicemia virus isolates from North America and Europe

Viral hemorrhagic septicemia virus (VHSV) is the cdusative agent of a serious rhabdoviral d~sease of rainbow trout Oncorhynchus myklss in Europe The first isolation of the vlrus in North Amenca occurred In the fall of 1988 when it was recovered from adult chinook 0 tshawytscha and coho 0 klsutch salmon returning to 2 hatcher~es in the state of Washington, USA The following year, VHSV was isolated from adult coho salmon at 2 other hatcher~es in northwestern Washington In 1990 and 1991, VHSV was recovered from Pacific cod Gadus macrocephalus caught in Pnnce Willlam Sound, Alaska Genetic vanation among the 4 isolates from salmon and the 1990 ~solate from Pacific cod was determ~ned uslng T1 nbonuclease finqerprlnt~ng In addition, 4 d~verse isolates from Europe were lncluded for companson The North Amencan isolates of VHSV formed a slngle fingerprint group In which the 4 isolates from salmonids were h~ghly similar to each other and the isolate from Pacific cod was related but less s~milar The 4 European ~solates which included an isolate from Atlantic cod G morhua, formed a second fingerpnnt group The genetic d~vers~ty among the isolates within each fingerpnnt group was estimated to be less than 5 % whlle the North Amencan and European strains of the virus were judged to differ by more than 5% The results indicate that the North Amerlcan isolates of VHSV are not of European ongln and that the virus may be enzootic wlthin the manne environment.

Diseases of Aquatic Organisms↗
USGS2018

Spatial and temporal patterns in population trends and burrow usage of burrowing owls in North America

Many researchers have suggested that abundance of Burrowing Owls ( Athene cunicularia ) has declined in many portions of their breeding range, but a thorough review of their population trends over time is lacking. Published population trends from the North American Breeding Bird Survey program suggested that Burrowing Owl populations in the US have declined over the past 60 yr, but the declines were not considered significant until 2014. However, accurate trend estimates and the statistical significance of those estimates were hampered by low relative abundance of owls. Moreover, many authors have suggested that eradication of burrowing animals is a major cause of Burrowing Owl declines, because burrows dug by burrowing animals are a critical resource for Western Burrowing Owls ( A. cunicularia hypugaea ). Despite this, we currently lack a range-wide summary of the burrowing animals on which Western Burrowing Owls depend. To help fill these two information gaps, my objectives were to: (1) use Breeding Bird Survey (BBS) data to examine geographic patterns in population trends of Burrowing Owls throughout their breeding range in the USA, and (2) use past studies to provide the first summary of the spatial extent to which Western Burrowing Owls rely on the suite of burrowing animals throughout their breeding range. Significantly more BBS routes in the US show declining counts of owls than show increasing or stable counts, and the declines were most apparent prior to 1995. Counts of Burrowing Owls declined most precipitously on the northern edge and southern edge of the owl's US breeding range. Western Burrowing Owls primarily use black-tailed prairie dog ( Cynomys ludovicianus ) burrows in the eastern portion of their breeding range, whereas the diversity of burrowing species on which the owls depend is much greater in the western and central portions of their breeding range. Burrowing owl declines have been most apparent in portions of their range where they rely primarily on Richardson's ground squirrels ( Urocitellus richardsonii ), California ground squirrels ( Otospermophilus beecheyi ), black-tailed prairie dogs, and American badgers ( Taxidea taxus ).

Journal of Raptor Research↗
USGS2022

Using a vegetation index to assess wetland condition in the Prairie Pothole Region of North America

Wetlands deliver a suite of ecosystem services to society. Anthropogenic activities, such as wetland drainage, have resulted in considerable wetland loss and degradation, diminishing the intrinsic value of wetland ecosystems worldwide. Protecting remaining wetlands and restoring degraded wetlands are common management practices to preserve and reclaim wetland benefits to society. Accordingly, methods for monitoring and assessing wetlands are required to evaluate their ecologic condition and outcomes of restoration activities. We used an established methodology for conducting vegetation-based assessments and describe a case study consisting of a wetland condition assessment in the Prairie Pothole Region of the North American Great Plains. We provide an overview of an existing method for selecting wetlands to sample across broad geographic distributions using a spatially balanced statistical design. We also describe site assessment protocols, including vegetation survey methods, and how field data were applied to a vegetation index that categorized wetlands according to ecologic condition. Results of the case study indicated that vegetation communities in nearly 50% of the surveyed wetlands were in very poor or poor condition, while only about 25% were considered good or very good . Approximately 70% of wetlands in native grasslands were categorized as good or very good compared to only 12% of those in reseeded grasslands (formerly cropland). In terms of informing restoration and management activities, results indicated that improved restoration practices could include a greater focus on establishing natural vegetation communities, and both restored and native prairie wetlands would benefit from enhanced management of invasive species.

Prairie Pothole Region↗