Biomass and productivity of seagrass communities in Exmouth Gulf, Western Australia

• Other Authors: Australian Institute of Marine Science (isOwnedBy)
• Format: Dataset
• Language: unknown
• Published: data.gov.au
• Subjects: Aquatic Ecosystems; Benthic Habitat; Biological Classification; Biomass; Biosphere; Carbon; Cymodocea angustata; Cymodocea serrulata; Ecological Dynamics; Growth; Halodule uninervis; Halophila ovalis; Nitrogen; Plants; Syringodium isoetifolium; Thalassodendron ciliatum; Vegetation; Tent Island
• Online Access: https://researchdata.edu.au/biomass-productivity-seagrass-western-australia/1925292; http://data.gov.au/dataset/b3e6dc9d-9e08-4d9c-9c82-cba816adb92c

In August/September 1995, visual surveys of seagrass abundance were undertaken along 47 transects, located along the eastern and western coasts of Exmouth Gulf. Transects extended from the shoreward to the seaward border of the zone vegetated with macrophytes. Spot checks were made at approximately every 10m to 20m along each transect and the percent cover and type of vegetation (identified to genus, where possible) were recorded. When there was taxonomic uncertainty, voucher specimens were taken for later identification.\n\nDestructive sampling was carried out along transects at three sites: Tent Island (2 transects), Simpson Island (2 transects) and Exmouth Town (3 transects). Five or ten 0.25m² quadrats were randomly placed along each 50m transect. Quadrats were photographed, the percent cover of macrophytes was estimated and the density of seagrass was measured. From each site, the species composition of 5 Cymodocea samples was quantified.\n\nAll biomass was removed from each quadrat including seagrass roots and rhizomes to a depth of 20cm. Below ground material from Thalassodendron ciliatum was not collected. After drying samples for 48 hours at 70°C, epiphytes were removed and the remaining sample was ashed for 18 hours at 450°C and the dry weight determined. Subsamples were analysed for total carbon and nitrogen.\n\nAt the three sites, all distal shoots of Cymodocea serrulata occurring along a 20m transect were tagged and at Exmouth, 25 shoots of Thalassodendron ciliatum were also tagged. After 6, 12 or 16 days (depending on the site), complete shoots were collected, measured and divided into new and old parts of leaves. The material was then dried and analysed for carbon and nitrogen content. Point of truth URL of this metadata record - http://gcmd.nasa.gov/Resources/valids/archives/keyword_list.html -