title: Variation in biogeochemical parameters across intertidal seagrass meadows in the central Great Barrier Reef region.
abstract: This survey provides baseline information on sediment characteristics, porewater, adsorbed and plant tissue nutrients from intertidal coastal seagrass meadows in the central region of the Great Barrier Reef World Heritage Area. Data collected from 11 locations, representative of intertidal coastal seagrass beds across the region, indicated that the chemical environment was typical of other tropical intertidal areas. Results using two different extraction methods highlight the need for caution when choosing an adsorbed phosphate extraction technique, as sediment type affects the analytical outcome. Comparison with published values indicates that the range of nutrient parameters measured is equivalent to those measured across tropical systems globally. However, the nutrient values in seagrass leaves and their molar ratios for Halophila ovalis and Halodule uninervis were much higher than the values from the literature from this and other regions, obtained using the same techniques, suggesting that these species act as nutrient sponges, in contrast with Zostera capricorni. The limited historical data from this region suggest that the nitrogen and phosphorus content of seagrass leaves has increased since the 1970s concomitant with changing land use practice.
authors.affiliation: School of Tropical Environment Studies and Geography, James Cook University, Townsville, Qld. 4811, Australia. jane.mellors@dpi.qld.gov.au
authors.forename: Jane
authors.initials: J
authors.lastname: Mellors
authors.forename: Michelle
authors.initials: M
authors.lastname: Waycott
authors.forename: Helene
authors.initials: H
authors.lastname: Marsh
mesh_terms: D000818:Animals; D037421:Anthozoa; D003625:Data Collection; D017753:Ecosystem; D004784:Environmental Monitoring; D019684:Magnoliopsida / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis* / Q000493:pharmacokinetics; D010758:Phosphorus / Q000032:analysis* / Q000493:pharmacokinetics; D011793:Queensland; D012016:Reference Values; D015203:Reproducibility of Results; D014329:Tropical Climate; D035962:Zosteraceae / Q000737:chemistry*
chemical_list: D010758:Phosphorus; D009584:Nitrogen