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Seasonal rainfall and runoff promote coral disease on an inshore reef.

Haapkylä J, Unsworth RK, Flavell M, Bourne DG, Schaffelke B, Willis BL - PLoS ONE (2011)

Bottom Line: Declining water quality coupled with the effects of climate change are rapidly increasing coral diseases on reefs worldwide, although links between coral diseases and environmental parameters remain poorly understood.The results suggest that rainfall and associated runoff may facilitate seasonal disease outbreaks, potentially by reducing host fitness or by increasing pathogen virulence due to higher availability of nutrients and organic matter.In the future, rainfall and seawater temperatures are likely to increase due to climate change which may lead to decreased health of inshore reefs.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence for Coral Reef Studies, School of Marine and Tropical Biology, James Cook University, Townsville, Australia. Jessica.Haapkyla@jcu.edu.au

ABSTRACT

Background: Declining water quality coupled with the effects of climate change are rapidly increasing coral diseases on reefs worldwide, although links between coral diseases and environmental parameters remain poorly understood. This is the first study to document a correlation between coral disease and water quality on an inshore reef.

Methodology/principal findings: The temporal dynamics of the coral disease atramentous necrosis (AN) was investigated over two years within inshore populations of Montipora aequituberculata in the central Great Barrier Reef, in relation to rainfall, salinity, temperature, water column chlorophyll a, suspended solids, sedimentation, dissolved organic carbon, and particulate nitrogen, phosphorus and organic carbon. Overall, mean AN prevalence was 10-fold greater during summer wet seasons than winter dry seasons. A 2.5-fold greater mean disease abundance was detected during the summer of 2009 (44 ± SE 6.7 diseased colonies per 25 m(2)), when rainfall was 1.6-fold greater than in the summer of 2008. Two water quality parameters explained 67% of the variance in monthly disease prevalence in a Partial Least Squares regression analysis; disease abundance was negatively correlated with salinity (R2 = -0.6) but positively correlated with water column particulate organic carbon concentration (R2 = 0.32). Seasonal temperature patterns were also positively correlated with disease abundance, but explained only a small portion of the variance.

Conclusions/significance: The results suggest that rainfall and associated runoff may facilitate seasonal disease outbreaks, potentially by reducing host fitness or by increasing pathogen virulence due to higher availability of nutrients and organic matter. In the future, rainfall and seawater temperatures are likely to increase due to climate change which may lead to decreased health of inshore reefs.

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Related in: MedlinePlus

PCA of environmental variables.Principal coordinates analysis (PCA) of the nine measured environmental                            variables. Vector overlays represent multiple correlations between                            ordination axes and environmental parameters. PC1 is associated with                            particulate phosphorus (PP) and nitrogen (PN),                                chlorophyll-a (chl-a) and salinity                            whereas PC2 is associated mainly with sedimentation (Sed), maximum                            temperature 14 days preceding and including the sampling date (Tmax 14d)                            maximum temperature 7 days preceding and including the sampling date                            (Tmax 7d) and particulate organic carbon (POC). Together PCA1 and PCA2                            axes capture 59.3% of the total variation of numbers of coral                            colonies with AN.
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pone-0016893-g005: PCA of environmental variables.Principal coordinates analysis (PCA) of the nine measured environmental variables. Vector overlays represent multiple correlations between ordination axes and environmental parameters. PC1 is associated with particulate phosphorus (PP) and nitrogen (PN), chlorophyll-a (chl-a) and salinity whereas PC2 is associated mainly with sedimentation (Sed), maximum temperature 14 days preceding and including the sampling date (Tmax 14d) maximum temperature 7 days preceding and including the sampling date (Tmax 7d) and particulate organic carbon (POC). Together PCA1 and PCA2 axes capture 59.3% of the total variation of numbers of coral colonies with AN.

Mentions: The exploratory multivariate ordination of the nine environmental parameters in a principal coordinates analysis (PCA) showed that some of the environmental variables were highly correlated (Fig. 5). The first principal component, PC1, was associated with water column concentrations of PP (eigenvalue −0.402), chlorophyll-a (chl-a; −0.382), PN (−0.361) and salinity (0.341). PC2 was associated with sedimentation (0.498), maximum temperature 14 days preceding and including the sampling date (Tmax 14d; 0.452), maximum temperature 7 days preceding and including the sampling date (Tmax 7d; 0.423) and POC (−0.417) (Fig. 5). Together, PC1 and PC2 explained 59.3% of the total variation in the data.


Seasonal rainfall and runoff promote coral disease on an inshore reef.

Haapkylä J, Unsworth RK, Flavell M, Bourne DG, Schaffelke B, Willis BL - PLoS ONE (2011)

PCA of environmental variables.Principal coordinates analysis (PCA) of the nine measured environmental                            variables. Vector overlays represent multiple correlations between                            ordination axes and environmental parameters. PC1 is associated with                            particulate phosphorus (PP) and nitrogen (PN),                                chlorophyll-a (chl-a) and salinity                            whereas PC2 is associated mainly with sedimentation (Sed), maximum                            temperature 14 days preceding and including the sampling date (Tmax 14d)                            maximum temperature 7 days preceding and including the sampling date                            (Tmax 7d) and particulate organic carbon (POC). Together PCA1 and PCA2                            axes capture 59.3% of the total variation of numbers of coral                            colonies with AN.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037388&req=5

pone-0016893-g005: PCA of environmental variables.Principal coordinates analysis (PCA) of the nine measured environmental variables. Vector overlays represent multiple correlations between ordination axes and environmental parameters. PC1 is associated with particulate phosphorus (PP) and nitrogen (PN), chlorophyll-a (chl-a) and salinity whereas PC2 is associated mainly with sedimentation (Sed), maximum temperature 14 days preceding and including the sampling date (Tmax 14d) maximum temperature 7 days preceding and including the sampling date (Tmax 7d) and particulate organic carbon (POC). Together PCA1 and PCA2 axes capture 59.3% of the total variation of numbers of coral colonies with AN.
Mentions: The exploratory multivariate ordination of the nine environmental parameters in a principal coordinates analysis (PCA) showed that some of the environmental variables were highly correlated (Fig. 5). The first principal component, PC1, was associated with water column concentrations of PP (eigenvalue −0.402), chlorophyll-a (chl-a; −0.382), PN (−0.361) and salinity (0.341). PC2 was associated with sedimentation (0.498), maximum temperature 14 days preceding and including the sampling date (Tmax 14d; 0.452), maximum temperature 7 days preceding and including the sampling date (Tmax 7d; 0.423) and POC (−0.417) (Fig. 5). Together, PC1 and PC2 explained 59.3% of the total variation in the data.

Bottom Line: Declining water quality coupled with the effects of climate change are rapidly increasing coral diseases on reefs worldwide, although links between coral diseases and environmental parameters remain poorly understood.The results suggest that rainfall and associated runoff may facilitate seasonal disease outbreaks, potentially by reducing host fitness or by increasing pathogen virulence due to higher availability of nutrients and organic matter.In the future, rainfall and seawater temperatures are likely to increase due to climate change which may lead to decreased health of inshore reefs.

View Article: PubMed Central - PubMed

Affiliation: ARC Centre of Excellence for Coral Reef Studies, School of Marine and Tropical Biology, James Cook University, Townsville, Australia. Jessica.Haapkyla@jcu.edu.au

ABSTRACT

Background: Declining water quality coupled with the effects of climate change are rapidly increasing coral diseases on reefs worldwide, although links between coral diseases and environmental parameters remain poorly understood. This is the first study to document a correlation between coral disease and water quality on an inshore reef.

Methodology/principal findings: The temporal dynamics of the coral disease atramentous necrosis (AN) was investigated over two years within inshore populations of Montipora aequituberculata in the central Great Barrier Reef, in relation to rainfall, salinity, temperature, water column chlorophyll a, suspended solids, sedimentation, dissolved organic carbon, and particulate nitrogen, phosphorus and organic carbon. Overall, mean AN prevalence was 10-fold greater during summer wet seasons than winter dry seasons. A 2.5-fold greater mean disease abundance was detected during the summer of 2009 (44 ± SE 6.7 diseased colonies per 25 m(2)), when rainfall was 1.6-fold greater than in the summer of 2008. Two water quality parameters explained 67% of the variance in monthly disease prevalence in a Partial Least Squares regression analysis; disease abundance was negatively correlated with salinity (R2 = -0.6) but positively correlated with water column particulate organic carbon concentration (R2 = 0.32). Seasonal temperature patterns were also positively correlated with disease abundance, but explained only a small portion of the variance.

Conclusions/significance: The results suggest that rainfall and associated runoff may facilitate seasonal disease outbreaks, potentially by reducing host fitness or by increasing pathogen virulence due to higher availability of nutrients and organic matter. In the future, rainfall and seawater temperatures are likely to increase due to climate change which may lead to decreased health of inshore reefs.

Show MeSH
Related in: MedlinePlus