| Title | Development of a new acoustic mapping method for eelgrass using a multi-beam echo-sounder |
| Download | Download (whole publication) |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Norton, A R; Dijkstra, S J |
| Source | Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada; by Todd, B J ; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Geological Survey of Canada, Open File 8295, 2017 p. 90, https://doi.org/10.4095/305905  Open Access |
| Links | GeoHab 2017
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| Year | 2017 |
| Publisher | Natural Resources Canada |
| Meeting | 2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; May 1-4, 2017 |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Program and abstracts: 2017
GeoHab Conference, Dartmouth, Nova Scotia, Canada |
| File format | pdf |
| Subjects | marine geology; surficial geology/geomorphology; environmental geology; geophysics; mapping techniques; oceanography; marine environments; coastal studies; conservation; marine organisms; marine
ecology; resource management; biological communities; environmental studies; ecosystems; vegetation; geophysical interpretations; acoustic surveys, marine; sonar surveys; photography; water quality; bathymetry; Biology; Data processing |
| Program | Offshore Geoscience |
| Released | 2017 09 26 |
| Abstract | Eelgrass plays important roles in temperate coastal ecosystems, including as primary producers and as habitat for many species. The distribution and health of eelgrass beds are also sometimes used as a
bio-indicator for water quality. The deepest edges of eelgrass beds are especially vulnerable to water quality issues because of the pre-existing light limitation with increasing depth due to natural light attenuation. However, the deep edges of beds
are also often the most difficult to delineate with satellite and aerial imagery often used for large-scale seagrass mapping programs; the use of aerial imagery for mapping eelgrass beds is also sometimes hindered by turbidity issues common in
estuarine environments. We are in particular developing methods to determine and map the maximum depth limit ('deep edge'), percent cover, functional type (i.e., macroalgae or eelgrass) and canopy height of the beds using water column backscatter
data from a multi-beam echo-sounder because these characteristics are difficult to obtain using existing optical and acoustic methods. Water column data was collected using an Odom MB1 sonar in 2014 and 2015 over a variety of vegetated sites in New
Hampshire and Massachusetts, selected to represent a range of conditions: dense/sparse eelgrass, long/short eelgrass, mixed macroalgae and eelgrass, eelgrass on muddy or hard substrates, etc. The data processing workflow will look at both echo and
terrain characteristics to determine the presence and characteristics of vegetation. In addition to sonar data, drop camera data was collected, and data from a regional aerial mapping program also exist for comparison. Initial data analysis shows
good agreement between drop camera and sonar detections, and patches as small as 1m2 and as short as 20 cm are detectable. |
| Summary | (Plain Language Summary, not published)
The sixteenth annual GeoHab Conference was held this year (2017) at the Waterfront Campus of the Nova Scotia Community College in Dartmouth, Nova Scotia,
Canada. |
| GEOSCAN ID | 305905 |
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