De’ath and Fabricius, 2008:

"Macroalgal cover increased steeply with declining water clarity at Secchi values <13 m, but was only weakly related to chlorophyll (Fig. 1). Macroalgal cover increased 3.5-fold (from 6 to 21%) as water clarity declined from 13 to 4 m, and additionally by 33% (from 9.5 to 12.5%) as chlorophyll increased from 0.3 to 0.8 μg L-1. Additionally, macroalgal cover declined fourfold across the shelf and four-fold along the shelf."

Figure 1. Partial effects plots of changes of macroalgal cover along gradients of water clarity (Secchi depth, in m), chlorophyll (µg L-1), and distance across (0 = coast, 1 = offshore) and along the shelf (0 = south, 1 = north). 

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Citation and/or URL

De'ath, G. & Fabricius, K.E. 2008, Water quality of the Great Barrier Reef: distributions, effects on biota and trigger values for the protection of ecosystem health: final report to the Great Barrier Reef Marine Park Authority. Research Publication 89, Great barrier Reef Marine Park Authority, Townsville, Australia

Spatial Coverage

Great Barrier Reef Marine Park

Temporal Coverage

Chlorophyll, nutrient and secchi data collected since 1976

Hard coral biodiversity data between 1994 and 2001 

Reef Plan Marine Monitoring Program since 2005 

Update Frequency

Annually

Other Information

None