Eelgrass (Zostera marina) characteristics, sediment grain size distributions, sediment total organic carbon contents (TOC), carbon isotope ratios of sediment organic matter, and total carbon to total nitrogen ratios were measured at four lower intertidal sites in Bellingham Bay, Washington, July 2-5, 2019.

This data release presents eelgrass distributions and bathymetry data derived from acoustic surveys of Bellingham Bay, Washington. Survey operations were conducted between February 16 and February 21, 2019 (USGS Field Activity Number 2019-606-FA) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center and Washington State Department of Ecology. Eelgrass and bathymetry data were collected from the R/V George Davidson equipped with a single-beam sonar system and global navigation satellite system (GNSS) receiver. The sonar system consisted of a Biosonics DT-X single-beam echosounder and 420 kHz transducer with a 6-degree beam angle. Depths from the echosounder were computed using sound velocity data measured using a YSI CastAway CTD during the survey. Positioning of the vessel was determined at 5 Hz using a Trimble R9s GNSS receiver and Trimble Zephyr Model 2 antenna operating in real time kinematic (RTK) mode. Differential corrections were transmitted by a cellular modem to the GNSS receiver on the survey vessel at 1-Hz from a GNSS continuously operating reference station operated by the Washington State Reference Network (WSRN; http://www.wsrn3.org/) located in the city of Bellingham (station BELI). Output from the GNSS and sonar systems were combined in real time by the Biosonics DT-X deck unit and output to a computer running HYPACK hydrographic survey software. Navigation information was displayed on a video monitor, allowing the vessel operator to navigate along predefined survey lines spaced at 25- to 100-m intervals alongshore at speeds of approximately 2 m/s. Acoustic backscatter data were analyzed using a custom graphical user interface (GUI) that implements a signal processing algorithm applied to each sonar sounding to extract the location of the bottom and presence of vegetation (Stevens and others, 2008 ). Individual acoustic returns along a survey line were grouped into packets of ten, and eelgrass percent cover was calculated as the fractional percent of acoustic returns that were classified as vegetated within each group, resulting in a estimate of percent cover every 4 to 5 m (depending on vessel speed). The positioning data from the bathymetric survey were postprocessed using Waypoint Grafnav to apply differential corrections with data recorded at the GNSS base station BELI and archived by the WSRN; these data superseded the original positions recorded in real time. The GUI was used to combine filtered sonar data with postprocessed positioning data and orthometric elevations relative to the NAVD88 vertical datum were computed using National Geodetic Survey Geoid12a offsets. The estimated vertical uncertainty of the bathymetric measurements ranged from 2.0 cm to 18.3 cm with a mean of 6.7 cm. Uncertainty in the vertical positions associated with pitch and roll of the survey vessel is unknown. The final point data are provided in a comma-separated text file and are projected in Cartesian coordinates using the Universal Transverse Mercator (UTM), Zone 10 north, meters coordinate system.

This dataset includes biological variables showing surf smelt spawning presence, geological variables describing beach composition, and sample locations using RTK-GPS. This field data was also used to run the Sea Level Affecting Marshes Model (SLAMM; Warren Pinnacle Consulting, Inc., Warren, Vt)) to predict the changes to beaches over time, and under different sea level rise scenarios. Field sampling took place on the northern part of Bainbridge Island, Puget Sound, Washington during summer and fall of 2010.

Gas fluxes (carbon dioxide, methane, nitrous oxide), sediment, environmental variables, nutrients, eelgrass and macroalgae data collected from coastal lagoons in southern Rhode Island in 2022 and 2023.

Sediment grain-size distributions and total organic carbon contents were measured at four intertidal sites and three subtidal sites along the urban waterfront (east shore) of Bellingham Bay, Washington, July 3-11, 2019 and June 6-August 31, 2020. Intertidal substrate was sampled in eelgrass beds, and subtidal substrate was sampled inside and outside of the deep edge of eelgrass beds.

This part of USGS Data Series 781 presents substrate, geomorphic, and geologic attributed polygons in the Offshore of the Eel River, California, map area, one of 83 map areas of the California State Waters Map Series. The polygons are derived from multibeam echosounder (MBES) data and derivatives of that data using video-supervised and unsupervised classification. Attributes and attribute values are named following the Coastal and Marine Ecological Classification Standard (CMECS; Federal Geographic Data Committee, 2012) to be useful for ecosystems management.

These data are in six tables relating to surveys of eelgrass beds in three bays adjacent to Togiak National Wildlife Refuge, in southwestern Alaska. The tables provide environmental conditions, eelgrass abundance, distribution, and measurements used to estimate overall biomass.

These data are in six tables relating to surveys of eelgrass beds in three bays adjacent to Togiak National Wildlife Refuge, in southwestern Alaska. The tables provide environmental conditions, eelgrass abundance, distribution, and measurements used to estimate overall biomass.

These data are related to surveys of eelgrass beds in Norma Bay, Izembek Lagoon, Alaska. The table provides eelgrass shoot lengths and density measurements from sampling in September 1987.

These data are related to surveys of eelgrass beds in Norma Bay, Izembek Lagoon, Alaska. The table provides eelgrass shoot lengths and density measurements from sampling in September 1987.