De'ath and Fabricius, 2008:

"The taxonomic richness of phototrophic octocorals increased by ~30% as water clarity increased from 5 to 15 m, and steeply declined by ~40% as chlorophyll increased from 0.25 to 0.5 g L-1 (Fig. 3). Richness was unaffected by water quality at Secchi depth >15 m and chlorophyll levels below 0.35. Richness declined steeply towards the inner shelf (<0.4 across) and increased to the north."

Figure 3. Partial effects plots of changes in the species richness of phototrophic octocorals 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

All of the 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