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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

Levels of chl a (μg L-1) on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin and Fitzroy), when larvae would be expected in the plankton (November-March).Average (a) natural chl a from 2011–2014 (n = 20; ±se), and (b) mean and (c) maximum chl a recorded for the week following major cyclone or flood events between 2009–2014 (n = 7; ±se). Data sourced from eReefs (http://www.bom.gov.au/marinewaterquality/).
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pone.0122010.g003: Levels of chl a (μg L-1) on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin and Fitzroy), when larvae would be expected in the plankton (November-March).Average (a) natural chl a from 2011–2014 (n = 20; ±se), and (b) mean and (c) maximum chl a recorded for the week following major cyclone or flood events between 2009–2014 (n = 7; ±se). Data sourced from eReefs (http://www.bom.gov.au/marinewaterquality/).

Mentions: Average natural levels of chl a on the GBR between 2011–2014 were ~1 μg chl a L-1 in coastal regions, but were lower for mid-shelf and offshore regions (~0.40 and ~0.20 μg chl a L-1, respectively) (Fig. 3; Tables 1, 3). Average levels of chl a for the week following major cyclone or flood events were similar to natural levels for each location (Fig. 3). However, average maximum values for the week following a major rainfall or storm event were much higher, reaching ~10 μg chl a L-1 in coastal regions, ~8 μg chl a L-1 mid-shelf, and 2–4 μg chl a L-1 offshore (Fig. 3). Peak values ranged from 5.34–23.24 μg chl a L-1 for coastal regions, to 2.13–17.00 μg chl a L-1 and 1.06–7.14 μg chl a L-1 on mid-shelf and offshore regions, respectively (Table 1). There was no significant difference in chl a at different latitudinal locations (Wet Tropics, Burdekin, Fitzroy). A Tukey’s HSD test revealed that chl a levels were significantly higher in coastal waters both naturally and following flood, rainfall or cyclone events (Fig. 3; Table 3).


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)

Levels of chl a (μg L-1) on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin and Fitzroy), when larvae would be expected in the plankton (November-March).Average (a) natural chl a from 2011–2014 (n = 20; ±se), and (b) mean and (c) maximum chl a recorded for the week following major cyclone or flood events between 2009–2014 (n = 7; ±se). Data sourced from eReefs (http://www.bom.gov.au/marinewaterquality/).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0122010.g003: Levels of chl a (μg L-1) on the Great Barrier Reef where hotspots of Acanthaster planci outbreaks occur (Wet Tropics, Burdekin and Fitzroy), when larvae would be expected in the plankton (November-March).Average (a) natural chl a from 2011–2014 (n = 20; ±se), and (b) mean and (c) maximum chl a recorded for the week following major cyclone or flood events between 2009–2014 (n = 7; ±se). Data sourced from eReefs (http://www.bom.gov.au/marinewaterquality/).
Mentions: Average natural levels of chl a on the GBR between 2011–2014 were ~1 μg chl a L-1 in coastal regions, but were lower for mid-shelf and offshore regions (~0.40 and ~0.20 μg chl a L-1, respectively) (Fig. 3; Tables 1, 3). Average levels of chl a for the week following major cyclone or flood events were similar to natural levels for each location (Fig. 3). However, average maximum values for the week following a major rainfall or storm event were much higher, reaching ~10 μg chl a L-1 in coastal regions, ~8 μg chl a L-1 mid-shelf, and 2–4 μg chl a L-1 offshore (Fig. 3). Peak values ranged from 5.34–23.24 μg chl a L-1 for coastal regions, to 2.13–17.00 μg chl a L-1 and 1.06–7.14 μg chl a L-1 on mid-shelf and offshore regions, respectively (Table 1). There was no significant difference in chl a at different latitudinal locations (Wet Tropics, Burdekin, Fitzroy). A Tukey’s HSD test revealed that chl a levels were significantly higher in coastal waters both naturally and following flood, rainfall or cyclone events (Fig. 3; Table 3).

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