Biomass and Productivity of Tropical Macroalgae on Three Nearshore Fringing Reefs in the Central Great Barrier Reef, Australia

Schaffelke, Britta; Klumpp, DW

doi:10.1515/botm.1997.40.1-6.373

Cited by 45 publications

(48 citation statements)

References 30 publications

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“…Several macroalgal taxa were observed interacting with corals only in the lagoon including fleshy macroalgal taxa Turbinaria, Sargassum, Padina, and Lobophora, which is consistent with previously reported spatial variation (Tanner, 1995;Rogers, 1997;Diaz-Pulido et al, 2007). A subset, Hydroclathrus, Colopomenia, Chnoospora, and Dictyota, were observed predominantly in spring, reflecting their ephemeral seasonality (Price, 1989;Rogers, 1997;Schaffelke and Klumpp, 1997;Diaz-Pulido et al, 2007). These results highlight the unique seasonality of macroalgal taxa, even within the same functional group, and demonstrate that shifts in macroalgal taxa influence the composition of coral-algal interactions.…”

Section: Modeling the Effect Of Benthic Cover On The Frequency Of Cormentioning

confidence: 98%

“…The effects of spatio-temporal variability on tropical macroalgae, however, have mostly been inferred from the occurrence of seasonal peaks and have principally focused on large, conspicuous species (i.e., Sargassum) that bloom in the austral summer (Vuki and Price, 1994;McCook, 1997;Lefèvre and Bellwood, 2010). Comparatively, little is known about a large proportion of macroalgae, which predominantly grow in the austral autumn, winter and spring (Price, 1989;Rogers, 1996Rogers, , 1997Schaffelke and Klumpp, 1997). Furthermore, environmental factors do not operate independently, and investigations into how temperature and light interact to influence macroalgal seasonality have been less clear (Mathieson and Dawes, 1986;Fong and Zedler, 1993;Ferrari et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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The Dynamics of Coral-Algal Interactions in Space and Time on the Southern Great Barrier Reef

et al. 2018

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Globally, tropical coral reefs are being degraded by human activities, and as a result, reef-building corals have declined while macroalgae have increased. Recent work has focused on measuring macroalgal abundance in response to anthropogenic stressors. To accurately evaluate the effects of human impacts, however, it is necessary to understand the effects of natural processes on reef condition. To better understand how coral reef communities are influenced by natural processes, we investigated how spatial and seasonal changes in environmental conditions (temperature and PAR) influence benthic community structure, and the composition and frequency of coral-algal interactions across eight distinct zones and over a 23-month period at Heron reef on the southern Great Barrier Reef. Hard coral cover and macroalgal density showed distinct spatio-temporal variations, both within and between zones. Broad hard coral cover was significantly higher at the reef slope sites compared to the lagoon and was not significantly influenced by season. The composition and biomass of macroalgae increased in spring and declined in summer, with maximum macroalgal abundance corresponding with average temperatures of between 22 and 24 • C and average 24 h PAR of 300-500 µmol qanta m −2 s −1 . Changes in macroalgal biomass further influenced the composition and frequency of coral-algal interactions, however the incidence of coral-algal contact was best explained by coral cover. The results presented here emphasize that natural levels of macroalgae and coral-algal interactions are context-specific, and vary not only with-in zones, but in somewhat predictable seasonal cycles. Further, these results emphasize that the frequency of coral-algal interactions is dependent on hard coral, not just macroalgal cover, and an increase in coral-algal interactions does not necessarily translate to degradation of coral reefs.

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Section: Modeling the Effect Of Benthic Cover On The Frequency Of Cormentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

The Dynamics of Coral-Algal Interactions in Space and Time on the Southern Great Barrier Reef

et al. 2018

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“…(Fucales, Phaeophyta) (e.g. McCook 1997, Schaffelke & Klumpp 1997. Several experimental studies based on the exclusion of herbivorous fishes from reef areas have highlighted the importance of macroherbivores in controlling not only the abundance of benthic macroalgae species but also the distribution patterns of algal communities (McClanahan et al 2003, Russ 2003, Ceccarelli et al 2006, Hughes et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Temporal variation in coral reef ecosystem processes: herbivory of macroalgae by fishes

Lefévre

Bellwood²

2011

Mar. Ecol. Prog. Ser.

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Despite the widely accepted importance of fish herbivory on coral reefs, few studies have considered the temporal variability in the nature of algal-herbivore interactions. We therefore quantified monthly feeding intensity on Sargassum sp. bioassays for 12 mo with remote underwater video cameras deployed to identify the herbivores responsible for macroalgal removal on an inshore island of the Great Barrier Reef, Australia. Significantly higher removal rates were observed during the summer months whereas winter months were characterized by 4 times lower removal rates. However, rather than being simply changes in the feeding activity of a single species, this temporal pattern in herbivory also incorporated changes in the species responsible for the removal of Sargassum. Video analyses revealed that, of the 43 herbivore species recorded from the bay, only 3 played a significant role in Sargassum removal: Kyphosus vaigiensis, Naso unicornis and Scarus rivulatus. K. vaigiensis, a rudderfish, was primarily responsible for the removal of Sargassum during the summer months (83% of the total recorded bites; 85 553 bites). There was almost no feeding activity on Sargassum by K. vaigiensis during the winter months (82 bites). However, there was a reciprocal increase in feeding intensity on Sargassum by parrotfishes in the winter months, particularly S. rivulatus (71 bites during summer versus 2884 bites in winter). This temporal variability in herbivore functional roles suggests that functional redundancy on reefs may be less than previously assumed in that the feeding activities of fishes may be both spatially and temporally constrained.

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“…High feeding pressure from herbivores generally diminishes macroalgae to the species rich 'algal turf' typical of coral reefs (Hatcher 1988(Hatcher , 1990. However, large brown algae occur in high abundances on nearshore reefs of the Great Barrier Reef, Australia (GBR), especially on reefs fringing granite continental islands (Morrissey 1980, Schaffelke & Klumpp 1997a. Among these macroalgae the genera Cystoseira, Horrnophysa, Sargassum, and Turbinaria are strikingly abundant in summer (MartinSmith 1993, Vuki & Price 1994, Schaffelke & Klumpp 1997a and are often regarded as diminishing the aesthetic value of nearshore reefs.…”

Section: Introductionmentioning

confidence: 99%

“…If macroalgae are nutnentlimited at these sites, increased nutrient availability may increase the potential for enhanced macroalgal growth. The objective of the present study was to evaluate the effect of enhanced nutrients on the growth of the large fucoid alga Sargassum bacculana (Mertens) C. Agardh, which dominated the macrophyte biomass at our study locations (Schaffelke & Klumpp 1997a). The objective of the experiments was to determine lim~t i n g and optimum concentrations of available nutrients (nitrogen, N and phosphorus, P) for growth of S.…”

Section: Introductionmentioning

confidence: 99%

Nutrient-limited growth of the coral reef macroalga Sargassum baccularia and experimental growth enhancement by nutrient addition in continuous flow culture

Schaffelke¹,

Klumpp²

1998

Mar. Ecol. Prog. Ser.

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ABSTRACT-The observed high biomass of Sargassum species and other fleshy macroalgae on nearshore coral reefs in the Great Barner Reef (Australia) raises the concern that this may be a sign of a phase shift from hard coral to dominance by algae, thus indicating the degradation of these reefs. Nearshore reefs are, due to their geographical position, exposed to inputs of nutnents and particles from mainland run-off. This study estimated the limiting and optimum nutrient concentrations for the growth of Sargassum baccularia under continuous supply of ammonium and phosphate. To assess the nutrient situation in the field, critical and subsistence levels of tlssue nutrients as determined in cultures were compared with field tissue nutrient levels, and a 'mlnl budget' was estimated that compares nutnent requirements with nutrient supply. The growth rates of S, baccularia almost doubled within the narrow window of substrate concentrations from 3 pM ammonium plus 0.3 pM phosphate to 5 pM ammonium plus 0.5 pM phosphate. Lower and, unexpectedly, higher nutrient concentrations resulted in reduced growth rates. Field thalli of S. baccularia were always sufficiently supplied with N and P to show positive growth rates. However, field growth was both N-and P-limited, particularly in austral summer, when fast growth of S. baccularia occurs. Thls was indicated by tissue N and P concentrations that fell below the respective critical nutrient values, and estimated nutrient demands that exceeded the nutrients available from the water column. We suggest that if land-derived nutrient inputs increased. S. baccularia would become nutrient-sufficient, especially during the summer wet season. This may increase the competitive potential of this species to colonise larger areas on the nearshore reefs.

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Biomass and Productivity of Tropical Macroalgae on Three Nearshore Fringing Reefs in the Central Great Barrier Reef, Australia

Cited by 45 publications

References 30 publications

The Dynamics of Coral-Algal Interactions in Space and Time on the Southern Great Barrier Reef

The Dynamics of Coral-Algal Interactions in Space and Time on the Southern Great Barrier Reef

Temporal variation in coral reef ecosystem processes: herbivory of macroalgae by fishes

Nutrient-limited growth of the coral reef macroalga Sargassum baccularia and experimental growth enhancement by nutrient addition in continuous flow culture

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