[Coral-List] Szmant 2002: Great review on nutrient enrichment on coral reefs

tomascik at novuscom.net tomascik at novuscom.net
Tue May 1 18:30:29 EDT 2018


Hi everyone,

Interesting reading and a strong sense of déjà vu. Nearly 20 years  
have past since the following unbiased paper was published

https://www.researchgate.net/publication/238782377_Paradise_lost_How_marine_science_failed_the_world's_coral_reefs

and yet based on these past exchanges we seem to be barking up the same tree..

Here is a link to a couple of papers for some additional thought,  
especially when it comes to the value of the ENCORE experiment.

https://www.researchgate.net/publication/257648028_Evidence_of_Large-Scale_Chronic_Eutrophication_in_the_Great_Barrier_Reef_Quantification_of_Chlorophyll_a_Thresholds_for_Sustaining_Coral_Reef_Communities

https://www.researchgate.net/publication/5992344_Reevaluation_of_ENCORE_Support_for_the_Eutrophication_Threshold_Model_for_Coral_Reefs

Cheers,
Tomas



Quoting "Bruno, John" <jbruno at unc.edu>:

> Dear listers,
>
> Over the weekend I read, for the 3rd or 4th time, Alina Szmant?s  
> (2002) incredible review "Nutrient Enrichment on Coral Reefs: Is It  
> a Major Cause of Coral Reef Decline?? and wanted to share it with you.
>
> It?s an amazing paper and a good example of how to critically  
> evaluate evidence for a perceived impact. Very thorough and  
> unbiased. You can download it here:   
> https://www.dropbox.com/s/q6j144vwzx66e2u/Szmant%202002.pdf?dl=0
>
>
> Here?s the abstract:
>
> Coral reefs are degrading worldwide at an alarming rate. Nutrient  
> over-enrichment is considered a major cause of this decline because  
> degraded coral reefs generally exhibit a shift from high coral cover  
> (low algal cover) to low coral cover with an accompanying high cover  
> and biomass of fleshy algae. Support for such claims is equivocal at  
> best. Critical examination of both experimental laboratory and field  
> studies of nutrient effects on corals and coral reefs, including the  
> Elevated Nutrient on Coral Reefs Experiment (ENCORE) enrichment  
> experiment conducted on the Great Barrier Reef, does not support the  
> idea that the levels of nutrient enrichment documented at  
> anthropogenically-enriched sites can affect the physiology of corals  
> in a harmful way, or for most cases, be the sole or major cause of  
> shifts in coral- algal abundance. Factors other than nutrient  
> enrichment can be significant causes of coral death and affect algal  
> cover, and include decreased abundance of grazing fishes by fishing,  
> and of grazing sea urchins to disease; grazing preferences of  
> remaining grazers; temperature stress that kills coral (i.e., coral  
> bleaching) and creates more open substrate for algal colonization;  
> sedimentation stress that can weaken adult corals and prevent coral  
> recruitment; coral diseases that may be secondary to coral  
> bleaching; and outbreaks of coral predators and sea urchins that may  
> be secondary effects of overfishing. Any factor that leads to coral  
> death or reduces levels of herbivory will leave more substrate open  
> for algal colonization or make the effects of even low-level  
> enrichment more severe. Factors that contribute to an imbalance  
> between production and consumption will result in community  
> structure changes similar to those expected from over- enrichment.  
> Over-enrichment can be and has been the cause of localized coral  
> reef degradation, but the case for widespread effects is not  
> substantiated.
>
>
>
>
>
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