SEAGRASS_WESTERN_PORT_1999 is a polygon layer defining the spatial extent, species distribution and density of seagrass and macroalgae in Western Port mapped from aerial photography in 1999.

The five species of seagrass occuring around the coast of Tasmania were located on a presence-absence basis. Sampling included the recording of species, depth, density, substratum and presence of algal epiphytes. Available aerial photography from three time periods (circa 1950, circa 1970 and circa 1990) was used to digitally map selected beds into a GIS using ARC/INFO. Sample site attributes were added to the database and patterns of change and distribution were analysed and mapped. An area of approx. 220 square kilometres was mapped leading to an estimate of between 400 and 500 square kilometres of seagrass occurring in Tasmania. Decline has occurred, particularly close to areas of human population and activity. The report proposes mechanisms for the management and protection of Tasmania's seagrass communities, and nominates representative areas for possible reserve status. Reference: Rees, CG 1994 Tasmanian Seagrass Communities, Masters Thesis, Centre for Environmental Studies, Department of Geography and Environmental Studies, University of Tasmania. Department of Geography and Environmental Studies, University of Tasmania.

This dataset shows the global distribution of seagrasses, and is composed of two subsets of point and polygon occurence data. The data were compiled by UNEP World Conservation Monitoring Centre in collaboration with Dr Frederick T. Short (University of New Hampshire, USA).

The five species of seagrass occuring around the coast of Tasmania were located on a presence-absence basis. Sampling included the recording of species, depth, density, substratum and presence of algal epiphytes. Available aerial photography from three time periods (circa 1950, circa 1970 and circa 1990) was used to digitally map selected beds into a GIS using ARC/INFO. Sample site attributes were added to the database and patterns of change and distribution were analysed and mapped. An area of approx. 220 square kilometres was mapped leading to an estimate of between 400 and 500 square kilometres of seagrass occurring in Tasmania. Decline has occurred, particularly close to areas of human population and activity. The report proposes mechanisms for the management and protection of Tasmania's seagrass communities, and nominates representative areas for possible reserve status. Reference: Rees, CG 1994 Tasmanian Seagrass Communities, Masters Thesis, Centre for Environmental Studies, Department of Geography and Environmental Studies, University of Tasmania. Department of Geography and Environmental Studies, University of Tasmania.

This layer presents the spatial extent, species distribution and density of seagrass meadows at Corner Inlet and Nooramunga mapped from 1998 aerial photography and field observations.

In 1999, the U.S. Geological Survey (USGS), in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.

This dataset summarises 40 years of seagrass data collection (1983-2022) within Torres Strait and the Gulf of Carpentaria into two GIS shapefiles: (1) a point shapefile that includes survey data for 48,612 geolocated sites, and (2) a polygon geopackage describing seagrass at 641 individual or composite meadows. Managing seagrass resources in northern Australia requires adequate baseline information on where seagrass is (presence/absence), the mapped extent of meadows, what species are present, and date of collection. This baseline is particularly important as a reference point against which to compare seagrass loss or change through time. The scale of northern Australia and the remoteness of many seagrass meadows from human populations present a challenge for research and management agencies reporting on the state of seagrass ecological indicators. Broad-scale and repeated surveys/studies of areas are logistically and financially impractical. However seagrass data is being collected through various projects which, although designed for specific reasons, are amenable to collating a picture of the extent and state of the seagrass resource. In this project we compiled seagrass spatial data collected during surveys in Torres Strait and the Gulf of Carpentaria into a standardised form with point-specific and meadow-specific spatial and temporal information. We revisited, evaluated, simplified, standardised, and corrected individual records, including those collected several decades ago by drawing on the knowledge of one of our authors (RG Coles) who led the early seagrass data collection and mapping programs. We also incorporate new data, such as from photo records of an aerial assessment of mangroves in the Gulf of Carpentaria in 2017. This project was funded by the National Environmental Science Programme (NESP) Marine and Coastal Hub and Torres Strait Regional Authority (TSRA) in partnership with the Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University. The project follows on from TropWATER’s previous work compiling 35 years of seagrass spatial point data and 30 years of seagrass meadow extent data for the Great Barrier Reef World Heritage Area (GBRWHA) and adjacent estuaries, funded through successive NESP Tropical Water Quality Hub Projects 3.1 (2015-2016) and 5.4 (2018-2020). These data sets are now publicly available through the eAtlas data portal: https://doi.org/10.25909/y1yk-9w85 . In making this data publicly available for management, the authors and data custodians request being contacted and involved in decision making processes that incorporate this data, to ensure its limitations are fully understood. Methods: The data were collected using a variety of survey methods to describe and monitor seagrass sites and meadows. For intertidal sites/meadows, these include walking, observations from helicopters in low hover, and observations from hovercraft when intertidal banks were exposed. For subtidal sites/meadows, methods included free diving, scuba diving, video transects from towed cameras attached to a sled with/without a sled net, video drops with filmed quadrats, trawl and net samples, and van Veen grab samples. These methods were selected and tailored by the data custodians to the location, habitat surveyed, and technology available. Important site and method descriptions and contextual information is contained in the original trip reports and publications for each data set provided in Table 1 of Carter et al. (2022). Geographic Information System (GIS) Mapping data for historic records (1980s) were transcribed from original logged and mapped data based on coastal topography, dead reckoning fixes and RADAR estimations. More recent data (1990’s onwards) is GPS located. All spatial data were converted to shapefiles with the same coordinate system (GDA 1994 Geoscience Australia Lambert), then compiled into a single point shapefile and a single polygon shapefile (seagrass meadows)

Hardy Inlet was surveyed by underwater drop camera observations in December 2018 and January 2020. Seagrass species distribution and cover (as percentage cover in categories: 0, 1-10%, 10-25%, 25-50%, 50-75%, 75-90%, 90-100%) were recorded. The canopy height (in 10 cm intervals) and epiphytic cover (as low, medium, high) of seagrass was also estimated. Macroalgae distribution and cover (as percentage cover in categories: 0, 1-10%, 10-25%, 25-50%, 50-75%, 75-90%, 90-100%) were recorded. At approximately a third of the sites, physical water profiles and secchi depth were recorded. The datasets making up the Hardy Inlet Seagrass Survey data are: Hardy_Seagrass - point dataset Hardy_Seagass_Extent - polygon showing presence/absence derived from points Hardy_Seagrass_Cover - polygon showing percentage cover derived from points Layers: Hardy_Seagrass_Dec_2018 - Hardy_seagrass points where Year = '2018' Hardy_Seagrass_Jan_2020 - Hardy_seagrass points where Year = '2020' Hardy_Seagrass_Extent_2018 - Hardy_Seagrass_Extent where Year = '2018' Hardy_Seagrass_Extent_Jan_2020 - Hardy_Seagrass_Extent where Year = '2020' Hardy_Seagrass_Cover_2018 - Hardy_Seagrass_Cover where Year = '2018' Hardy_Seagrass_Cover_Jan_2020 - Hardy_Seagrass_Cover where Year = '2020'

Hardy Inlet was surveyed by underwater drop camera observations in December 2018 and January 2020. Seagrass species distribution and cover (as percentage cover in categories: 0, 1-10%, 10-25%, 25-50%, 50-75%, 75-90%, 90-100%) were recorded. The canopy height (in 10 cm intervals) and epiphytic cover (as low, medium, high) of seagrass was also estimated. Macroalgae distribution and cover (as percentage cover in categories: 0, 1-10%, 10-25%, 25-50%, 50-75%, 75-90%, 90-100%) were recorded. At approximately a third of the sites, physical water profiles and secchi depth were recorded. The datasets making up the Hardy Inlet Seagrass Survey data are: Hardy_Seagrass - point dataset Hardy_Seagass_Extent - polygon showing presence/absence derived from points Hardy_Seagrass_Cover - polygon showing percentage cover derived from points Layers: Hardy_Seagrass_Dec_2018 - Hardy_seagrass points where Year = '2018' Hardy_Seagrass_Jan_2020 - Hardy_seagrass points where Year = '2020' Hardy_Seagrass_Extent_2018 - Hardy_Seagrass_Extent where Year = '2018' Hardy_Seagrass_Extent_Jan_2020 - Hardy_Seagrass_Extent where Year = '2020' Hardy_Seagrass_Cover_2018 - Hardy_Seagrass_Cover where Year = '2018' Hardy_Seagrass_Cover_Jan_2020 - Hardy_Seagrass_Cover where Year = '2020'

The coverage is the extent of seagrass beds in Tampa Bay.