Cyclone Sadie flood plumes in the Great Barrier Reef Lagoon : composition and consequences : proceedings of a workshop held in Townsville Queensland, Australia, 10 November 1994, at the Australian Institute of Marine Science

In late January of 1994, cyclone Sadie brought intense rainfall to north Queensland catchments, first significant monsoonal event since 1991. Several organisations responded, by monitoring composition and fate of these riverine waters as they flowed through catchments and into nearshore marine waters of the Great Barrier Reef lagoon

Long-term chlorophyll monitoring in the Great Barrier Reef Lagoon : status report 1, 1993-1995

In 1992 the Great Barrier Reef Marine Park Authority initiated the Great Barrier Reef Nutrient Status Monitoring Network (hereafter the Network). The broad objectives of the Network are to document the nutrient status of regional waters within the Great Barrier Reef lagoon using chlorophyll a concentration as a proxy nutrient bioindicator. Chlorophyll a is used in preference to routine nutrient analysis because (a) chlorophyll a integrates change in nutrient availability over time; (b) samples are comparatively simple to collect; and (c) chlorophyll a is comparatively inexpensive to analyse. The Network was conceived to be ongoing, and to complement and collaborate with a number of other existing monitoring programs to ensure comprehensive reporting of the status of the Great Barrier Reef (GBR)

A pilot study of baseline levels of water quality around Green Island

A pilot study was undertaken at Green Island in June 1989 to assess the spatial and temporal variation of a range of water quality parameters. It was a precursor to the implementation of a proposed baseline study of water quality around Green Island to ensure the optimum allocation of sampling in a cost effective manner

Sedimentation resulting from road development, Cape Tribulation Area

The aims of the study were: to quantify the amount of sediment being carried by the streams of the Cape Tribulation area under both natural conditions and in disturbed areas adjacent to the New Road; to quantity the amount of sediment in the water column adjacent to the reefs; and to put into context the amount of increased sedimentation directly due to road developmen

Nutrient uptake by coral-reef microatolls

We measured rates of ammonium and phosphate uptake into 12 microatolls at One Tree reef lagoon, Australia, on 14 occasions over a range of seasonal and meteorological conditions from 1993 to 1995. Nine of the microatolls were spiked with ammonia and/or phosphate every low tide (2.5–4 h) during low- (15-month) and high- (13-month) loading periods. The remaining three microatolls that were not spiked with nutrient served as reference conditions. Ammonium concentrations were elevated from an average background of 0.7 to 11 µM NH 4 during the low-loading period and 36 µM NH 4 during the high-loading period, resulting in a loading to the benthos of 3.5 and 18 mmol NH 4 m –2 low tide –1. Phosphate concentrations were elevated from an average background of 0.2 to 2.3 and 5.1 µM PO 4 during low- and high-loading periods, respectively, resulting in a loading of 0.66 and 3.9 mmol PO 4 m –2 low tide –1. Ammonium and phosphate concentrations decreased significantly over low-tides, and uptake rates were proportional to concentrations (first-order). The average uptake-rate constant, S (m s –1), for ammonium and phosphate did not differ between the two loading periods but was highly variable. Averaged over both loading periods, S for ammonium was 129±74×10 –6 m s –1and S for phosphate was 67±39×10 –6 m s –1. At background nutrient concentrations, estimated nutrient-uptake rates were 7.8 mmol NH 4 m –2 day –1 and 1.2 mmol PO 4 m –2 day –1. Excretion rates—calculated from the mean difference in uptake rates measured in reference and nutrient-enriched microatolls—were estimated to be 4.3 mmol NH 4 m –2 day –1 and 0.9 mmol PO 4 m –2 day –1. We reason and suggest that nutrient uptake rates in these microatolls were close to mass-transfer limited rates. We conclude that nutrient uptake into coral reefs can be highly dynamic, varying 10-fold spatially and temporally