Spatial and temporal patterns of near-surface chlorophyll a in the Great Barrier Reef lagoon

Brodie, Jon; De’ath, Glenn; Devlin, Michelle; Furnas, Miles; Wright, Margaret E.

doi:10.1071/mf06236

Cited by 147 publications

(117 citation statements)

References 34 publications

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“…Coastal waters adjacent to agricultural lands have higher concentrations of dissolved and particulate nutrients, chlorophyll a and suspended sediments, especially during the summer wet season, compared to coastal areas adjacent to undeveloped catchments and offshore areas (e.g., Brodie et al 2007;Cooper et al 2007). However, water quality parameters are highly variable in space and time which necessitates frequent measurements to adequately determine true concentration ranges.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

2009

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Although the debate about coral reef decline focuses on global disturbances (e.g., increasing temperatures and acidification), local stressors (nutrient runoff and overfishing) continue to affect reef health and resilience. The effectiveness of foraminiferal and hard-coral assemblages as indicators of changes in water quality was assessed on 27 inshore reefs along the Great Barrier Reef. Environmental variables (i.e., several water quality and sediment parameters) and the composition of both benthic foraminiferal and hard-coral assemblages differed significantly between four regions (Whitsunday, Burdekin, Fitzroy, and the Wet Tropics). Grain size and organic carbon and nitrogen content of sediments, and a composite water column parameter (based on turbidity and concentrations of particulate matter) explained a significant amount of variation in the data (tested by redundancy analyses) in both assemblages. Heterotrophic species of foraminifera were dominant in sediments with high organic content and in localities with low light availability, whereas symbiontbearing mixotrophic species were dominant elsewhere. A similar suite of parameters explained 89% of the variation in the FORAM index (a Caribbean coral reef health indicator) and 61% in foraminiferal species richness. Coral richness was not related to environmental setting. Coral assemblages varied in response to environmental variables, but were strongly shaped by acute disturbances (e.g., cyclones, Acanthaster planci outbreaks, and bleaching), thus different coral assemblages may be found at sites with the same environmental conditions. Disturbances also affect foraminiferal assemblages, but they appeared to recover more rapidly than corals. Foraminiferal assemblages are effective bioindicators of turbidity/light regimes and organic enrichment of sediments on coral reefs.

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Section: Introductionmentioning

confidence: 99%

Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

2009

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“…However, these relationships were generally from temperate areas and few measurements were included from tropical river catchments. The nutrient run-off issue is of particular concern for tropical river catchments adjacent to the Great Barrier Reef (GBR) because of possible downstream impacts of additional nutrients on this coral reef ecosystem (Fabricius 2005;DeVantier et al 2006;Brodie et al 2007a).…”

Section: Introductionmentioning

confidence: 99%

“…The downstream impacts of this run-off into GBR waters are of major concern; however, the direct effects of agricultural run-off on reef communities have been difficult to measure and are, as a result, controversial. Recent research DeVantier et al 2006) has shown a decline in hard-coral richness within the latitudinal zone of 14-18 • S, together with an increase in chlorophyll a concentrations in the central inshore GBR lagoon (Brodie et al 2007a). This zone of apparent change lies adjacent to coastal catchments with high levels of fertiliser-additive land use (FALU), mostly sugarcane, which is relatively close to the GBR.…”

Section: Introductionmentioning

confidence: 99%

Relationships between land use and nutrient concentrations in streams draining a 'wet-tropics' catchment in northern Australia

Mitchell

Reghenzani²,

Faithful

et al. 2009

Mar. Freshwater Res.

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Abstract. Differences in stream nutrient concentrations typically reflect upstream differences in land use. In particular, nitrate concentrations are greatly increased by losses from nitrogen (N) fertiliser applied to areas of intensive cropping. In the present study, a relationship between the area of such land use and the nitrate concentrations in the receiving streams was predicted. This relationship was tested using several data sets from the Tully basin, in the wet-tropics bioregion of north Queensland, Australia. The proportions of fertiliser-additive land use (FALU), mostly sugarcane and bananas, were correlated with the concentrations of nutrients in streams that drain these land uses. The data compared included two longterm sampling studies in the Tully River catchment and more recent, broader catchment sampling and plot-scale studies in this region. A strong relationship was shown for nitrate, but weaker relationships were observed for other N-nutrient and P-nutrient forms. Comparisons were made with contemporary and historical land-use changes in the Tully basin. The strong relationship of FALU with nitrate provides evidence that the nitrate exports from this catchment are largely derived from fertiliser use. This relationship can be used to derive nitrate run-off coefficients for fertilised land use in catchment models or to monitor changes following management to reduce fertiliser usage.

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“…Chl-a concentrations in the waters off Cape York average 0.2 µg L −1 , whereas in the area of coral reef biodiversity loss (wet tropics coast) concentrations average 0.7 µg L −1 . The difference is ascribed to the increased nutrient discharge from rivers such as the Tully caused by increased erosion and fertiliser loss (Mitchell et al 2001(Mitchell et al , 2009Furnas 2003;McKergow et al 2005a;Brodie et al 2007). Water quality trigger values for the GBRWHA have been set for chl-a at 0.6 µg L −1 for inshore waters (Moss et al 2005) and later to 0.5 µg L −1 (GBRMPA 2008; since then reduced to 0.45 µg L −1 ), and this value (0.5 µg L −1 ) was used as the GBR target for the Tully WQIP.…”

Section: Target Setting For the Tully-murray Basin For Nitratementioning

confidence: 99%

Target setting for pollutant discharge management of rivers in the Great Barrier Reef catchment area

Brodie

Lewis

Bainbridge

et al. 2009

Mar. Freshwater Res.

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Abstract. Water Quality Improvement Plans (WQIPs) are being developed for individual river basins on the Great Barrier Reef (GBR) catchment associated with the GBR Water Quality Protection Plan. Within each WQIP, marine ecosystem targets are linked to end-of-river pollutant (suspended sediments, nutrients and pesticides) load targets and to farm level management practice targets. The targets are linked through quantitative models; e.g. one model connects GBR chlorophyll concentrations (marine target) to end-of-river nitrate loads, a second connects the end-of-river nitrate loads to fertiliser management targets in the catchment, whereas a third model links fertiliser application to nitrate loss at the farm scale. The difficulties of applying these linked models to derive credible and practical management targets are great, given the high degree of uncertainty in each model. Our understanding of the generation of suspended sediments, nutrients and pesticides in catchments and the relationship to on-farm management, the transport of these materials to the ocean, their transport in coastal waters and their effects on marine ecosystems is incomplete. The challenge is to produce estimates from the models, with known levels of uncertainty, but robust enough for management purposes. Case studies from the Tully-Murray basin and the Burdekin basin in north Queensland are discussed.

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Spatial and temporal patterns of near-surface chlorophyll a in the Great Barrier Reef lagoon

Cited by 147 publications

References 34 publications

Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia

Relationships between land use and nutrient concentrations in streams draining a 'wet-tropics' catchment in northern Australia

Target setting for pollutant discharge management of rivers in the Great Barrier Reef catchment area

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