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Larval starvation to satiation: influence of nutrient regime on the success of Acanthaster planci.

Wolfe K, Graba-Landry A, Dworjanyn SA, Byrne M - PLoS ONE (2015)

Bottom Line: The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth.Development was less successful above and below this food treatment.Enhanced larval performance at 1 μg chl a L(-1) provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia.

ABSTRACT
High density populations of the crown-of-thorns seastar, Acanthaster planci, are a major contributor to the decline of coral reefs, however the causes behind periodic outbreaks of this species are not understood. The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth. The larval resilience hypothesis suggests that A. planci larvae naturally thrive in tropical oligotrophic waters. Both hypotheses remain to be tested empirically. We raised A. planci larvae in a range of food regimes from starvation (no food) to satiation (excess food). Algal cell concentration and chlorophyll levels were used to reflect phytoplankton conditions in nature for oligotrophic waters (0-100 cells ml(-1); 0-0.01 μg chl a L(-1)), natural background levels of nutrients on the Great Barrier Reef (GBR) (1,000-10,000 cells ml(-1); 0.1-1.0 μg chl a L(-1)), and enhanced eutrophic conditions following runoff events (100,000 cells ml(-1); 10 μg chl a L(-1)). We determine how these food levels affected larval growth and survival, and the metamorphic link between larval experience and juvenile quality (size) in experiments where food ration per larvae was carefully controlled. Phytoplankton levels of 1 μg chl a L(-1), close to background levels for some reefs on the GBR and following flood events, were optimal for larval success. Development was less successful above and below this food treatment. Enhanced larval performance at 1 μg chl a L(-1) provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks.

No MeSH data available.


Related in: MedlinePlus

Regions on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin, Fitzroy), with indication of coastal, mid-shelf and offshore reefs.The ‘initiation box’ for A. planci outbreaks between Cooktown and Cairns [12] is indicated by the rectangle.
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pone.0122010.g001: Regions on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin, Fitzroy), with indication of coastal, mid-shelf and offshore reefs.The ‘initiation box’ for A. planci outbreaks between Cooktown and Cairns [12] is indicated by the rectangle.

Mentions: With respect to natural levels of chl a on the GBR, satellite data collected by eReefs (http://www.bom.gov.au/marinewaterquality/) is congruent to that recorded in previous studies based on analyses by discrete water samples (S1 Table) [38,39]. Natural levels of chl a on the GBR were determined from reference data from eReefs for the time Acanthaster planci larvae would be expected in the plankton (five months; November-March). Monthly data, as provided by eReefs, were assimilated for four years (2010–2014) (n = 20; Table 1). Average natural chl a concentration (μg chl a L-1) was determined for regions on the GBR where hotspots of A. planci outbreaks occur; the Wet Tropics (Cairns/Lizard Island), Burdekin (Townsville) and Fitzroy (Swains Reef) Regions (Fig. 1; Table 1). In each region, data were divided into coastal, mid-shelf and offshore locations (Fig. 1).


Larval starvation to satiation: influence of nutrient regime on the success of Acanthaster planci.

Wolfe K, Graba-Landry A, Dworjanyn SA, Byrne M - PLoS ONE (2015)

Regions on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin, Fitzroy), with indication of coastal, mid-shelf and offshore reefs.The ‘initiation box’ for A. planci outbreaks between Cooktown and Cairns [12] is indicated by the rectangle.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4366153&req=5

pone.0122010.g001: Regions on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin, Fitzroy), with indication of coastal, mid-shelf and offshore reefs.The ‘initiation box’ for A. planci outbreaks between Cooktown and Cairns [12] is indicated by the rectangle.
Mentions: With respect to natural levels of chl a on the GBR, satellite data collected by eReefs (http://www.bom.gov.au/marinewaterquality/) is congruent to that recorded in previous studies based on analyses by discrete water samples (S1 Table) [38,39]. Natural levels of chl a on the GBR were determined from reference data from eReefs for the time Acanthaster planci larvae would be expected in the plankton (five months; November-March). Monthly data, as provided by eReefs, were assimilated for four years (2010–2014) (n = 20; Table 1). Average natural chl a concentration (μg chl a L-1) was determined for regions on the GBR where hotspots of A. planci outbreaks occur; the Wet Tropics (Cairns/Lizard Island), Burdekin (Townsville) and Fitzroy (Swains Reef) Regions (Fig. 1; Table 1). In each region, data were divided into coastal, mid-shelf and offshore locations (Fig. 1).

Bottom Line: The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth.Development was less successful above and below this food treatment.Enhanced larval performance at 1 μg chl a L(-1) provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia.

ABSTRACT
High density populations of the crown-of-thorns seastar, Acanthaster planci, are a major contributor to the decline of coral reefs, however the causes behind periodic outbreaks of this species are not understood. The enhanced nutrients hypothesis posits that pulses of enhanced larval food in eutrophic waters facilitate metamorphic success with a flow-on effect for population growth. The larval resilience hypothesis suggests that A. planci larvae naturally thrive in tropical oligotrophic waters. Both hypotheses remain to be tested empirically. We raised A. planci larvae in a range of food regimes from starvation (no food) to satiation (excess food). Algal cell concentration and chlorophyll levels were used to reflect phytoplankton conditions in nature for oligotrophic waters (0-100 cells ml(-1); 0-0.01 μg chl a L(-1)), natural background levels of nutrients on the Great Barrier Reef (GBR) (1,000-10,000 cells ml(-1); 0.1-1.0 μg chl a L(-1)), and enhanced eutrophic conditions following runoff events (100,000 cells ml(-1); 10 μg chl a L(-1)). We determine how these food levels affected larval growth and survival, and the metamorphic link between larval experience and juvenile quality (size) in experiments where food ration per larvae was carefully controlled. Phytoplankton levels of 1 μg chl a L(-1), close to background levels for some reefs on the GBR and following flood events, were optimal for larval success. Development was less successful above and below this food treatment. Enhanced larval performance at 1 μg chl a L(-1) provides empirical support for the enhanced nutrients hypothesis, but up to a limit, and emphasizes the need for appropriate mitigation strategies to reduce eutrophication and the consequent risk of A. planci outbreaks.

No MeSH data available.


Related in: MedlinePlus