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Mary McGann

Research Geologist at the USGS Pacific Coastal and Marine Science Center

Science and Products

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Grid of photomicrographs and sketches of foraminifera.

Transport of invasive microorganisms

This research is part of the project, “Sediment Transport in Coastal Environments.”
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Transport of invasive microorganisms

This research is part of the project, “Sediment Transport in Coastal Environments.”
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View from the sky looking at mouth of river with lots of sediment deposited at a beach.

Sediment Transport in Coastal Environments

Our research goals are to provide the scientific information, knowledge, and tools required to ensure that decisions about land and resource use, management practices, and future development in the coastal zone and adjacent watersheds can be evaluated with a complete understanding of the probable effects on coastal ecosystems and communities, and a full assessment of their vulnerability to natural...
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
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Sediment Transport in Coastal Environments

Our research goals are to provide the scientific information, knowledge, and tools required to ensure that decisions about land and resource use, management practices, and future development in the coastal zone and adjacent watersheds can be evaluated with a complete understanding of the probable effects on coastal ecosystems and communities, and a full assessment of their vulnerability to natural...
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A building after an earthquake has crumbled the roof and brick walls, the interior is now visible.

U.S. West Coast and Alaska Marine Geohazards

Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis. Devastating earthquakes in Japan (2011) and Chile (2010) that spawned pan-oceanic tsunamis sent a sobering reminder that U.S. coastlines are also vulnerable to natural disasters that originate in the ocean...
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories
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U.S. West Coast and Alaska Marine Geohazards

Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis. Devastating earthquakes in Japan (2011) and Chile (2010) that spawned pan-oceanic tsunamis sent a sobering reminder that U.S. coastlines are also vulnerable to natural disasters that originate in the ocean...
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Census counts of benthic foraminifera, environmental parameters (temperature, salinity, and oxygen concentration), and radiocarbon measurements from cores obtained under and near a whale-fall off western Vancouver Island, British Columbia, Canada

This data release provides census counts of benthic foraminifera (in percent for the total fauna and as raw counts for just the living specimens) as well as environmental parameters (temperature, salinity, and oxygen concentration) at the sampling sites, and radiocarbon measurements from selected push core samples obtained under and near a whale-fall off western Vancouver Island, British Columbia,
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Grain-size data from core S3-15G, Monterey Fan, Central California

This data release presents sediment grain-size data from samples collected from core S3-15G, a 4.72-m long gravity core collected at a depth of 3,491 meters on the western levy of the Monterey Fan on May 31, 1978 (USGS Field Activity S-3-78-SC).
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Geophysical properties, geochronologic, and geochemical data of sediment cores collected from San Pablo Bay, California, October 17-20, 2016

Geophysical properties (P-wave velocity, gamma ray density, and magnetic susceptibility), geochronologic (radiocarbon, excess Lead-210, and Cesium-137), and geochemical data (organic carbon content and 60 element contents) are reported for select vibracores collected aboard the S/V Retriever October 17-20, 2016 in San Pablo Bay, California. Geophysical properties were measured with a Geotek Multi-
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Donated ROV vibracore and sampling data collected during Monterey Bay Aquarium Research Institute cruises in 2019 offshore of south-central California

This dataset includes photographs of vibracores that were collected by the Monterey Bay Aquarium Research Institute (MBARI) in February 2019 and November 2019 aboard the R/V Western Flyer using the remotely operated vehicle (ROV) Doc Ricketts. The collection of these cores was funded entirely by MBARI, and the cores have been donated to the U.S. Geological Survey (USGS). The cores were collected i
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Sediment core data from the northern flank of Monterey Canyon, offshore California

The five files included in this U.S. Geological Survey data release are data from a set of sediment cores acquired from the continental slope, north of Monterey Canyon, offshore central California. Vibracores and push cores were collected with the Monterey Bay Aquarium Research Institutes remotely operated vehicle (ROV) Doc Ricketts in 2014 (cruise ID 2014-615-FA; http://cmgds.marine.usgs.gov/fan_
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Sediment core data from offshore Palos Verdes, California

The seven files included in this U.S. Geological Survey data release are data from a set of sediment cores acquired from the continental slope, offshore Los Angeles and the Palos Verdes Peninsula, adjacent to the Palos Verdes Fault. Gravity cores were collected by the USGS in 2009 (cruise ID S-I2-09-SC; http://cmgds.marine.usgs.gov/fan_info.php?fan=SI209SC), and vibracores were collected with the
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Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center
Filter Total Items: 29

Marine paleoseismic evidence for seismic and aseismic slip along the Hayward-Rodgers Creek fault system in northern San Pablo Bay

Distinguishing between seismic and aseismic fault slip in the geologic record is difficult, yet fundamental to estimating the seismic potential of faults and the likelihood of multi-fault ruptures. We integrated chirp sub-bottom imaging with targeted cross-fault coring and core analyses of sedimentary proxy data to characterize vertical deformation and slip behavior within an extensional fault ben
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Potential use of the benthic foraminifers Bulimina denudata and Eggerelloides advenus in marine sediment toxicity testing

The benthic foraminifers Bulimina denudata and Eggerelloides advenus are commonly abundant in offshore regions in the Pacific Ocean, especially in waste-discharge sites. The relationship between their abundance and standard macrofaunal sediment toxicity tests (amphipod survival and sea urchin fertilization) as well as sediment chemistry analyte measurements were determined for sediments collected
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers

Turbidity currents dominate sediment transfer into the deep ocean, and can damage critical seabed infrastructure. It is commonly inferred that powerful turbidity currents are triggered by major external events, such as storms, river floods, or earthquakes. However, basic models for turbidity current triggering remain poorly tested, with few studies accurately recording precise flow timing. Here, w
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Focused fluid flow and methane venting along the Queen Charlotte fault, offshore Alaska (USA) and British Columbia (Canada)

Fluid seepage along obliquely deforming plate boundaries can be an important indicator of crustal permeability and influence on fault-zone mechanics and hydrocarbon migration. The ~850-km-long Queen Charlotte fault (QCF) is the dominant structure along the right-lateral transform boundary that separates the Pacific and North American tectonic plates offshore southeastern Alaska (USA) and western B
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

What determines the downstream evolution of turbidity currents?

Seabed sediment flows called turbidity currents form some of the largest sediment accumulations, deepest canyons and longest channel systems on Earth. Only rivers transport comparable sediment volumes over such large areas; but there are far fewer measurements from turbidity currents, ensuring they are much more poorly understood. Turbidity currents differ fundamentally from rivers, as turbidity c
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Shallow-water foraminifera and other microscopic biota of Clipperton Island, tropical eastern Pacific

The recent foraminiferal fauna and associated microbiota of Clipperton Island (10.2833°N, 109.2167°W) were investigated at 20 sites collected in the intertidal zone around the perimeter of the island and from the edge of the inner brackish-water lagoon. Due to the island’s geographic location in a low productivity zone, a lack of variable habitats on and surrounding the island, and heavy surf that
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

A ship's ballasting history as an indicator of foraminiferal invasion potential--An example from Prince William Sound, Alaska, USA

We investigated the potential role of ballast sediment from coastal and transoceanic oil tankers arriving and de-ballasting in Port Valdez as a vector for the introduction of invasive benthic foraminifera in Prince William Sound, Alaska. Forty-one ballast sediment samples were obtained in 1998-1999 from 11 oil tankers that routinely discharged their ballast in Prince William Sound after sailing fr
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Sediment and organic carbon transport and deposition driven by internal tides along Monterey Canyon, offshore California

Submarine canyons provide globally important conduits for sediment and organic carbon transport into the deep-sea. Using a novel dataset from Monterey Canyon, offshore central California, that includes an extensive array of water column sampling devices, we address how fine-grained sediment and organic carbon are transported, mixed, fractionated, and buried along a submarine canyon. Anderson-type
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Linking direct measurements of turbidity currents to submarine canyon-floor deposits

Submarine canyons are conduits for episodic and powerful sediment density flows (commonly called turbidity currents) that move globally significant amounts of terrestrial sediment and organic carbon into the deep sea, forming some of the largest sedimentary deposits on Earth. The only record available for most turbidity currents is the deposit they leave behind. Therefore, to understand turbidity
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Discovery of an extensive deep-sea fossil serpulid reef associated with a cold seep, Santa Monica Basin, California

Multi-beam mapping of the Santa Monica Basin in the eastern Pacific has revealed the existence of a number of elevated bathymetric features, or mounds, harboring cold seep communities. During 2013-2014, mounds at ~600 m water depth were observed for the first time and sampled by Monterey Bay Aquarium Research Institute’s ROV Doc Ricketts. Active cold seeps were found, but surprisingly one of these
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

Initial dispersal (1986-1987) of the invasive foraminifera Trochammina hadai Uchio in San Francisco Bay, California, USA

A time series of three closely-spaced data sets are used to track the early expansion of the invasive Japanese benthic foraminifera Trochammina hadai in the southern portion of San Francisco Bay known as South Bay. The species initially appeared in 1983, comprising only 1.5% of the assemblage in one of four samples that were dominated by the native species Ammonia tepida and Cribroelphidium excava
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

The occurrence of the invasive foraminifera Trochammina hadai Uchio in Flamengo Inlet, Ubatuba, São Paulo State, Brazil

The agglutinated foraminifera Trochammina hadai Uchio (1962), a dominant species in Japan, first appeared as an invasive species in San Francisco Bay, US, in 1983. Trochammina hadai's first appearance in the Brazilian coastal waters of Flamengo Inlet, Ubatuba, Sao Paulo State, is recorded nearly three decades later, in two of thirty-four sediment samples collected in the western portion known as "
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Natural Hazards, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center

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