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At least 577 records · Page 32Linked to original sources
USGS2011

Integrating science and resource management in Tampa Bay, Florida

Tampa Bay is recognized internationally for its remarkable progress towards recovery since it was pronounced "dead" in the late 1970s. Due to significant efforts by local governments, industries and private citizens throughout the watershed, water clarity in Tampa Bay is now equal to what it was in 1950, when population in the watershed was less than one-quarter of what it is today. Seagrass extent has increased by more than 8,000 acres since the mid-1980s, and fish and wildlife populations are increasing. Central to this successful turn-around has been the Tampa Bay resource management community's long-term commitment to development and implementation of strong science-based management strategies. Research institutions and agencies, including Eckerd College, the Florida Wildlife Commission Fish and Wildlife Research Institute, Mote Marine Laboratory, National Oceanic and Atmospheric Administration, the Southwest Florida Water Management District, University of South Florida, U.S. Environmental Protection Agency, U.S. Geological Survey, local and State governments, and private companies contribute significantly to the scientific basis of our understanding of Tampa Bay's structure and ecological function. Resource management agencies, including the Tampa Bay Regional Planning Council's Agency on Bay Management, the Southwest Florida Water Management District's Surface Water Improvement and Management Program, and the Tampa Bay Estuary Program, depend upon this scientific basis to develop and implement regional adaptive management programs. The importance of integrating science with management has become fully recognized by scientists and managers throughout the region, State and Nation. Scientific studies conducted in Tampa Bay over the past 10–15 years are increasingly diverse and complex, and resource management programs reflect our increased knowledge of geology, hydrology and hydrodynamics, ecology and restoration techniques. However, a synthesis of this research and its integration into resource management has not been prepared for Tampa Bay since the mid-1980s. The need for an up-to-date synthesis of Tampa Bay science and management has resulted in the production of this document. The U.S. Geological Survey recently completed a 5-year Tampa Bay Integrated Science Study, and the Tampa Bay Estuary Program updated the Comprehensive Conservation and Management Plan for Tampa Bay in 2006. These efforts build upon results of the many research and management studies and programs summarized here.

Florida↗
USGS2017

Terrestrial subaqueous seafloor dunes: Possible analogs for Venus

Dunes on Venus, first discovered with Magellan Synthetic Aperture Radar (SAR) in the early 1990s, have fueled discussions about the viability of Venusian dunes and aeolian grain transport. Confined to two locations on Venus, the existence of the interpreted dunes provides evidence that there could be transportable material being mobilized into aeolian bedforms at the surface. However, because of the high-pressure high-temperature surface conditions, laboratory analog studies are difficult to conduct and results are difficult to extrapolate to full-sized, aeolian bedforms. Field sites of desert dunes, which are well-studied on Earth and Mars, are not analogous to what is observed on Venus because of the differences in the fluid environments. One potentially underexplored possibility in planetary science for Venus-analog dune fields could be subaqueous, seafloor dune fields on Earth. Known to the marine geology communities since the early 1960s, seafloor dunes are rarely cited in planetary aeolian bedform literature, but could provide a necessary thick-atmosphere extension to the classically studied aeolian dune environment literature for thinner atmospheres. Through discussion of the similarity of the two environments, and examples of dunes and ripples cited in marine literature, we provide evidence that subaqueous seafloor dunes could serve as analogs for dunes on Venus. Furthermore, the evidence presented here demonstrates the usefulness of the marine literature for thick-atmosphere planetary environments and potentially for upcoming habitable worlds and oceanic environment research program opportunities. Such useful cross-disciplinary discussion of dune environments is applicable to many planetary environments (Earth, Mars, Venus, Titan, etc.) and potential future missions.

Aeolian Research↗
USGS2018

Distinguishing brackish lacustrine from brackish marine deposits in the stratigraphic record: A case study from the late Miocene and early Pliocene Bouse Formation, Arizona and California, USA

Brackish marine and brackish continental environments are fundamentally different from a compositional perspective. Brackish water is often defined as having salinity lower than that of standard seawater but higher than that of freshwater, but less regard is given to the origin of the salts involved. The simple dilution of standard seawater by freshwater in a coastal or estuarine setting constitutes a brackish environment, but so do lakes where continental fresh water is impounded and becomes more saline through a variety of solute evolution pathways. The range of potential compositions of brackish lake water is diverse and includes water with “seawater-like” compositions. Isolated brackish lake environments located hundreds of kilometers inland can evolve towards sodium chloride-dominated, low alkalinityenvironments that mimic the composition of brackish seawater environments. These types of lakes can harbor a variety of continentally invasive but typically marine organisms, including but not limited to algae, foraminifers, mollusks, diatoms, and crustaceans . Distinguishing brackish marine from brackish lake environments in the geologic record can be difficult. In this paper, the enigmatic late Miocene and early Pliocene southern Bouse Formation of southern Arizona and California, USA, considered by many to represent a marine transgression along the lower Colorado River corridor, is discussed within a broad framework that incorporates hydrochemical, biogeographical, and species niche concepts. A brackish lake interpretation provides a powerful platform that can comprehensively account for the enigmatic mixed marine and continental fossil assemblage and possible tidal rhythmites that feature prominently in the southern Bouse Formation controversy. A review of the broader regional (paleo)environmental context for the southern Bouse supports a sodium chloride-dominated, low alkalinity, mildly brackish (10-5 ppt) Colorado River-fed lake depositional environment that was populated by an intriguing but predictable array of euryhaline, opportunistic, and continentally invasive marginal marine organisms.

Arizona, California↗
USGS2005

Systematics of halogen elements and their radioisotopes in thermal springs of the Cascade Range, Central Oregon, Western USA

This study quantifies the cycling of halogen elements through the Cascadia subduction zone based on the chemistry of thermal springs in the Central Oregon Cascade Range and of a mineral spring in the forearc (Willamette Valley). Considerations based on mass balances, element ratios, and 36 Cl/Cl and 129 I/I ratios suggest that halogens discharged through the thermal springs in the Cascade Range are probably derived from magma degassing. Our results indicate that < 35% of the subducted Cl and < 20% of the subducted Br and I could be transported through arc volcanism and the thermal springs, a considerably lower percentage than estimated for other volcanic arcs along the Pacific Rim. A likely explanation for this difference is that a large fraction of the halogens is released from the slab at shallow depths into the serpentinized sub-forearc mantle because of the relatively high temperatures in the subducting Juan de Fuca plate. The small fraction of halogens subducted to depth probably also indicates a low rate of water transport, which is consistent with the observation that the Cascade Range sub-arc mantle is relatively dry and has a low degree of volcanic vigor, compared with other arcs.

Oregon↗
USGS2002

Seafloor geology of the Monterey Bay area continental shelf

Acoustic swath-mapping of the greater Monterey Bay area continental shelf from Point An??o Nuevo to Point Sur reveals complex patterns of rock outcrops on the shelf, and coarse-sand bodies that occur in distinct depressions on the inner and mid-shelves. Most of the rock outcrops are erosional cuestas of dipping Tertiary rocks that make up the bedrock of the surrounding lands. A mid-shelf mud belt of Holocene sediment buries the Tertiary rocks in a continuous, 6-km-wide zone on the northern Monterey Bay shelf. Rock exposures occur on the inner shelf, near tectonically uplifting highlands, and on the outer shelf, beyond the reach of the mud depositing on the mid-shelf since the Holocene sea-level rise. The sediment-starved shelf off the Monterey Peninsula and south to Point Sur has a very thin cover of Holocene sediment, and bedrock outcrops occur across the whole shelf, with Salinian granite outcrops surrounding the Monterey Peninsula. Coarse-sand deposits occur both bounded within low-relief rippled scour depressions, and in broad sheets in areas like the Sur Platform where fine sediment sources are limited. The greatest concentrations of coarse-sand deposits occur on the southern Monterey Bay shelf and the Sur shelf. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS2002

Suspended sediment transport on the continental shelf near Davenport, California

Suspended sediment transport on the shelves off Santa Cruz and Davenport, California is studied using field measurements and bottom boundary layer modeling. Strong transport events mostly occur during storms in winter; the volume of winter sediment transport is at least one order of magnitude greater than that of summer/spring transport. Rock outcrops on the inner shelf (< 40 m of water) indicates an erosional environment, but an elongated mid-shelf mud deposit evidently suggests a depositional environment on the mid-shelf. The seafloor geology appears to correlate to the poleward and offshore sediment transport pattern. This study also suggests that suspended sediment moves out of Monterey Bay, roughly along the isobaths of the northern bay. This fine material, originally from river sources, and the material from the coastal cliff erosion that is subsequently introduced to the transport system through cross-shelf sediment transport, are believed to be the sources of the mid-shelf mud deposit. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS1968

Mazama ash in the Northeastern Pacific

Volcanic glass in marine sediments off Oregon and Washington correlates with continental deposits of Mount Mazama ash by stratigraphic position, refractive index, and radiocarbon dating. Ash deposited in the abyssal regions by turbidity currents is used for tracing of the dispersal routes of postglacial sediments and for evaluation of marine sedimentary processes.

Oregon, Washington↗
USGS2017

The California Seafloor and Coastal Mapping Program – Providing science and geospatial data for California's State Waters

The California Seafloor and Coastal Mapping Program (CSCMP) is a collaborative effort to develop comprehensive bathymetric, geologic, and habitat maps and data for California's State Waters. CSCMP began in 2007 when the California Ocean Protection Council (OPC) and the National Oceanic and Atmospheric Administration (NOAA) allocated funding for high-resolution bathymetric mapping, largely to support the California Marine Life Protection Act and to update nautical charts. Collaboration and support from the U.S. Geological Survey and other partners has led to development and dissemination of one of the world's largest seafloor-mapping datasets. CSCMP provides essential science and data for ocean and coastal management, stimulates and enables research, and raises public education and awareness of coastal and ocean issues. Specific applications include: •Delineation and designation of marine protected areas •Characterization and modeling of benthic habitats and ecosystems •Updating nautical charts •Earthquake hazard assessments •Tsunami hazard assessments •Planning offshore infrastructure •Providing baselines for monitoring change •Input to models of sediment transport, coastal erosion, and coastal flooding •Regional sediment management •Understanding coastal aquifers •Providing geospatial data for emergency response

California↗
USGS2003

USGS Alaska Tissue Archival Projects: An update on FY02 activities

The banking of environmental specimens under cryogenic conditions for future retrospective analysis has been recognized for many years as an important part of environmental monitoring programs. Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has been collecting tissue samples from marine mammals for archival in the National Biomonitoring Specimen Bank (NBSB) at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, USA. The USGS, Alaska Biological Science Center (ABSC), the NOAA Fisheries, Office of Protected Resources (NMFS), and the NIST conduct this partnership project, which began under the Mineral Management Service (MMS) Outer Continental Shelf Environmental Assessment Program. MMS remains the primary client agency for the AMMTAP providing programmatic guidance and review. The purpose of the project is to collect tissue samples from Alaska marine mammals and to store these specimens under the best conditions so that they can be analyzed for environmental contaminants and other constituents. A substantial part of the sample collection is from Arctic species and, since most of the animals sampled are from Alaska Native subsistence harvests, the project relies on cooperation and collaboration with several Alaska Native organizations and local governmental agencies. Although a substantial amount of recent research has been conducted on contaminants in Alaskan marine mammals, few data exists on colonial seabirds nesting in Alaska. Like marine mammals, seabirds are an important group of upper trophic level marine organisms with a potential for accumulating lipophilic contaminants and are identified by MMS as species of interest for monitoring activities. More than 95% of the seabirds breeding in the continental United States nest at colonies in the Bering and Chukchi seas and Gulf of Alaska (see USFWS 1992). Realizing the value of colonial seabirds in environmental monitoring and the lack of recent data from Alaskan seabird colonies, the U.S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge (USFWS-AMNWR), the U.S. Geological Survey Biological Resources Division (USGS-BRD), and the National Institute of Standards and Technology (NIST) initiated the Seabird Tissue Archival and Monitoring Project (STAMP) in 1998. The project was designed as a 100-year-long program to monitor long-term trends in environmental quality by collecting eggs at nesting colonies using standardized protocols, banking the egg contents under conditions that ensure chemical stability during long-term (decadal) storage, and analyzing subsamples of the stored material to establish baseline levels for persistent bioaccumulative contaminants (e.g., chlorinated pesticides, PCBs, mercury).

Conference Paper↗
USGS2002

Relationship of gas hydrate concentration to porosity and reflection amplitude in a research well, Mackenzie Delta, Canada

Well logs acquired at the Mallik 2L-38 gas hydrate research well. Mackenzie Delta, Canada, reveal a distinct trend showing that the resistivity of gas-hydrate-bearing sediments increases with increases in density porosities. This trend, opposite to the general trend of decrease in resistivity with porosity, implies that gas hydrates are more concentrated in the higher porosity. Using the Mallik 2L-38 well data, a proportional gas hydrate concentration (PGHC) model, which states that the gas hydrate concentration in the sediment's pore space is linearly proportional to porosity, is proposed for the general habitat of gas hydrate in sediments. Anomalous data (less than 6% of the total data) outside the dominant observed trend can be explained by local geological characteristics. The anomalous data analysis indicates that highly concentrated gas-hydrate-bearing layers would be expected where sediments have high proportions of gravel and coarse sand. Using the parameters in the PGHC model determined from resistivity-porosity logs, it is possible to qualitatively predict the degree of reflection amplitude variations in seismic profiles. Moderate-to-strong reflections are expected for the Mallik 2L-38 well. ?? 2002 Elsevier Science Ltd. All rights reserved.

Marine and Petroleum Geology↗
USGS2009

U.S. Geological Survey (USGS) Western Region; Santa Barbara Channel Coastal and Ocean Science

USGS coastal and ocean science in the Western United States and the Pacific integrates scientific expertise in geology, water resources, biology, and geography. Operating from 10 major science centers in the Western Region, the USGS is addressing a broad geographic and thematic range of important coastal and marine issues. In California, the Santa Barbara Channel represents one area of focus.

Fact Sheet↗
USGS2002

Hydrocarbons in recent sediment of the Monterey Bay National Marine Sanctuary

A complex mixture of hydrocarbons is present in the recent sediment of the Monterey Bay National Marine Sanctuary. Eighteen samples from the continental shelf between San Francisco and Monterey contain aliphatic and aromatic hydrocarbons showing biological contributions from both marine and terrigenous sources, with the terrigenous indicators more pronounced near Monterey. Of particular interest, however, is a low-level background of petroleum-related compounds, including 28,30-bisnorhopane and 18??+??(H)-oleanane, which are characteristic of many crude oils from the Monterey Formation of California. Thus, the sediments are overprinted by a regional chemical signature which may be derived from eroded Monterey Formation rocks and from onshore and offshore seeps releasing petroleum from Monterey Formation source rocks. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS2014

Resource manager information needs regarding hydrologic regime shifts for the North Pacific Landscape Conservation

Landscape Conservation Cooperatives (LCCs) are a network of 22 public-private partnerships, defined by ecoregion, that share and provide science to ensure the sustainability of land, water, wildlife, and cultural resources in North America. LCCs were established by the U.S. Department of the Interior (DOI) in recognition of the fact that response to climate change must be coordinated on a landscape-level basis because important resources, ecosystem processes, and resource management challenges extend beyond most of the boundaries considered in current natural resource management. The North Pacific LCC (NPLCC) covers the range of the Pacific coastal temperate rainforest, including an area of 528,360 km 2 spanning 22 degrees of latitude from the Kenai Peninsula, Alaska, to Bodega Bay, California. The coverage area includes parts of four States, two Canadian provinces, and more than 100 Tribes and First Nation language groups. It extends from alpine areas at the crest of coastal mountains across subalpine, montane, and lowland forests to the nearshore marine environment. This wide range of latitudes and elevation zones; terrestrial, freshwater, and marine habitats; and complex jurisdictional boundaries hosts a diversity of natural resources and their corresponding management issues are equally diverse. As evidenced by the Science and Traditional Ecological Knowledge (S-TEK) Strategy guiding principles, identifying and responding to the needs of resource managers is key to the success of the NPLCC. To help achieve this goal of the NPLCC, the U.S. Geological Survey (USGS) has organized several workshops with resource managers and resource scientists to identify management information needs relevant to the priority topics identified in the S-TEK Strategy. Here, we detail the results from a first workshop to address the effects of changes in hydrologic regime on rivers, streams, and riparian corridors. The workshop focused on a subset of the full NPLCC geography and was structured to answer the following questions: What are the valued resources and services that may be affected by hydrologic regime changes in the region? What are the management goals for those resources? How is climate change anticipated to affect valued resources and goals? What adaptation strategies may managers use in response to anticipated changes in resources due to climate-related hydrologic change? What information is needed to inform and use management responses?

Open-File Report↗
USGS2002

Hydrocarbon geochemistry of cold seeps in the Monterey Bay National Marine Sanctuary

Samples from four geographically and tectonically discrete cold seeps named Clam Flat, Clamfield, Horseshoe Scarp South, and Tubeworm City, within the Monterey Bay National Marine Sanctuary were analyzed for their hydrocarbon content. The sediment contains gaseous hydrocarbons and CO2, as well as high molecular weight aliphatic and aromatic hydrocarbons with various combinations of thermogenic and biogenic contributions from petroleum, marine, and terrigenous sources. Of particular interest is the cold seep site at Clamfield which is characterized by the presence of thermogenic hydrocarbons including oil that can likely be correlated with oil-saturated strata at Majors Creek near Davenport, CA, USA. At Clam Flat, the evidence for thermogenic hydrocarbons is equivocal. At Horseshoe Scarp South and Tubeworm City, hydrocarbon gases, mainly methane, are likely microbial in origin. These varied sources of hydrocarbon gases highlight the diverse chemical systems that appear at cold seep communities. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS2000

Formation of ferromanganese crusts on northwest intertropical Pacific seamounts: Electron photomicrography and microprobe chemistry

Seven ferromanganese crusts from the northwest intertropical Pacific seamounts were analyzed for photomicroscopic growth structures, microprobe chemistry, and ages based on Co-chronometer growth rate. The crusts on the Marshall Islands seamounts are thick and ale divided into phosphatized lower older and nonphosphatized upper younger growth generations: the older crust consists of compact laminations and columns impregnated with carbonate fluoapatite (CFA), whereas the younger crust is characterized by porous botryoids and columns of ??-MnO2 and Fe oxyhydroxide. The crusts on the Federated States of Micronesia (FSM) and Palau Islands seamounts are thin and are often incorporated with inorganic opal-A in the uppermost part, comprising the younger generation. Some crusts show scours and fractures. Although the growth of crusts has been often interrupted by mass failure of slope sediments, the crusts on the Marshall Islands seamounts are estimated to have grown at rate of about 3 mm/Ma since the middle Eocene and to have been phosphatized in the late Oligocene during the host seamounts were located beneath the equatorial zone of high productivity. Prolonged infiltration of the oxygen minimum zone (OMZ) water into shallower water older crusts redistributed crust composition by precipitating CFA, enriching subsequent amounts of Mn and Ni, and removing some Co. The younger crust has formed at slower rate (about 2 mm/Ma) under the stronger influence of bottom-water circulation in the north of the equatorial zone, concentrating abundant Co. In the uppermost part of some crusts, siliceous skeletons transform with burial to inorganic opal-A and Si-rich Fe oxyhydroxide, suggesting that biosilica diagenesis can enhance crust growth. (C) 2000 Elsevier Science B.V.

Marine Geology↗
USGS2011

Rapid growth in the early marine period improves the marine survival of Chinook salmon (Oncorhynchus tshawytscha) in Puget Sound, Washington

We examined the effect of early marine entry timing and body size on the marine (smolt-to-adult) survival of Puget Sound Chinook salmon ( Oncorhynchus tshawytscha ). We used data from coded wire tag release groups of hatchery Chinook salmon to test whether hatchery release date, release size, and size in offshore waters in July and September influenced marine survival. Marine survival was most strongly related to the average body size in July, with larger sizes associated with higher survivals. This relationship was consistent over multiple years (1997–2002), suggesting that mortality after July is strongly size-dependent. Release size and date only slightly improved this relationship, whereas size in September showed little relationship to marine survival. Specifically, fish that experienced the highest marine survivals were released before 25 May and were larger than 17 g (or 120 mm fork length) by July. Our findings highlight the importance of local conditions in Puget Sound (Washington, USA) during the spring and summer, and suggest that declines in marine survival since the 1980s may have been caused by reductions in the quality of feeding and growing conditions during early marine life.

Washington↗
USGS2017

Sea turtles, light pollution, and citizen science: A preliminary report

Sea turtles are an important ecological resource for Gulf Islands National Seashore’s (Gulf Islands) waters and shorelines. Regionally, sea turtles face anthropogenic threats from situations such as entanglement in fishing gear and ingestion of marine debris, as well as possible changes in sex ratios due to increasing temperatures related to human-induced global warming. Locally, light pollution from residential, commercial, and industrial neighborhoods from nearby cities impacts the entirety of Gulf Islands, which spans 160 miles along the Gulf Coast, from Florida to Mississippi, and includes critical habitat for threatened and endangered sea turtles. Because light pollution has been hypothesized to negatively impact sea turtle nesting and hatchling survival, Gulf Islands undertook an effort to understand the relationship between light pollution and sea turtles and create unique educational and outreach opportunities by launching a citizen science program called Turtle Teens Helping in the Seashore (Turtle THIS). At the onset, the Turtle THIS program had two primary goals: quantify the association between light pollution and sea turtle nesting and hatching events using rigorous scientific methods; and initiate a citizen science volunteer program to provide youth with hands-on science and environmental stewardship roles, where they also gain employable skills and career opportunities. With multiple scientific hypotheses to consider, the development of a citizen science program became crucial. Such circumstances allowed Turtle THIS to grow a volunteer and intern program, quantify hypothesized light effects on sea turtles through developed methods, and begin to gather preliminary findings.

Florida↗