Benthic microalgae in coral reef sediments of the southern Great Barrier Reef, Australia

Heil, Cynthia A.; Chaston, Kathy; Jones, Alison; Bird, Paul; Longstaff, Ben; Costanzo, S. D.; Dennison, William C.

doi:10.1007/s00338-004-0390-1

Cited by 39 publications

(38 citation statements)

References 37 publications

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“…Uthicke & Klumpp (1997 and Uthicke (2001) demonstrated production enhancement in situ and in aquaria within 12 h, and biomass enhancement after several days of ammonium enhancement (either added directly or as an excretion product from benthic invertebrates) of only 1 to 2 µM above background level. Similarly, several other studies (Dizon & Yap 2003, Heil et al 2004, Gottschalk 2005) demonstrated rapid production enhancement or biomass increases of coral reef microphytobenthos upon N addition, for both inshore sediments similar in carbonate content to the inner zones investigated here and also for sediments with carbonate content as high as on midshelf reefs.…”

Section: Background Fluorescence Quantum Efficiency and Minimum Fluosupporting

confidence: 86%

Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia

Uthicke¹

2006

Mar. Ecol. Prog. Ser.

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The use of pulse-amplitude modulated (PAM) fluorometry in situ and in vivo as an indicator for nutrient and light status of microphytobenthos communities was investigated on the Great Barrier Reef. The 10 reefs investigated were located along a previously described water quality gradient, confirmed by sediment chemistry parameters (C org , N) and incident light measurements. Estimates of the efficiency of Photosystem II (PSII) were biased when not corrected for background fluorescence that increased with increasing inorganic C content of the sediments. Uncorrected values mimicked a decline in quantum efficiency towards areas with presumed lower nutrient levels. Upon correction, maximum and effective quantum efficiency (ca. 0.59) did not vary significantly along the gradient. The maximum quantum efficiency (F v /F m,corr ) measured after dark-adaptation did not differ statistically from effective quantum efficiency in the field (φ PSII,corr ). F 0 values measured in the laboratory were much lower than in situ F readings, indicating a higher concentration of biomass on the surface of the sediment in the field. Rapid light curve parameters (initial slope α, relative electron transport rate at light saturation rETR max , irradiance at onset of light saturation E k ) were lower during in vitro readings than in situ. rETR max and α values exhibited no statistical differences along the gradient. In contrast, E k increased towards midshelf reefs and correlated with incident PAR, indicating that microphytobenthos communities were highly adapted to incident light conditions. Because coral reef microphytobenthos was previously shown to be nitrogen limited, it was unexpected that efficiency measurements would not vary. It is hypothesised that, due to potential for differential vertical migration, the actual species involved in photosynthesis at a given time are nutrient sufficient. Higher nutrient supply may change the community composition on the surface to dominance by species with higher productivity. KEY WORDS: PAM · WQ gradient · Benthic microalgae (BMA) · Nutrient limitation · Light limitationResale or republication not permitted without written consent of the publisher

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Section: Background Fluorescence Quantum Efficiency and Minimum Fluosupporting

confidence: 86%

Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia

Uthicke¹

2006

Mar. Ecol. Prog. Ser.

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“…2). This rapid increase in benthic production when more N became available reflects strong N limitation, which has also been shown for BMA in coral reef sediments (Dizon and Yap 1999;Heil et al 2004;Clavier et al 2005). However, despite these numerous previous studies of the interaction between BMA and N in coral reef sediments (e.g., Dizon and Yap 1999;Heil et al 2004;Clavier et al 2005), only one other study has considered DON as a N source (Boucher and Clavier 1990); Boucher and Clavier (1990) also found an uptake of DON by the benthos (bacteria and BMA) in sandy sediments.…”

Section: Discussionmentioning

confidence: 68%

“…Numerous studies have found a N-limited response in benthic communities (Dizon and Yap 1999;Heil et al 2004), and water column N : P ratios are typically ,16 (Furnas et al 1990;Charpy 2001), suggesting short-term N limitation of coral reef ecosystems. In addition, biogeochemical process in coral reef sediments such as denitrification have also been shown to increase after N additions (Koop et al 2001).…”

mentioning

confidence: 99%

Mass coral spawning: A natural large‐scale nutrient addition experiment

Eyre

Glud

Patten

2008

Limnology & Oceanography

112

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A mass coral spawning event on the Heron Island reef flat in 2005 provided a unique opportunity to examine the response of a coral reef ecosystem to a large episodic nutrient addition. A post-major spawning phytoplankton bloom resulted in only a small drawdown of dissolved inorganic phosphorus (DIP minimum 5 0.37 mmol L 21 ), compared with almost complete removal of dissolved inorganic nitrogen (DIN) (minimum NO, suggesting that pelagic primary production is potentially N limited on the timescale of this study. DIN, DIP, dissolved organic nitrogen (DON), and dissolved organic phosphorus were used in the production of biomass, and mass balance calculations highlighted the importance of organic forms of N and P for benthic and pelagic production in tropical coral reef environments characterized by low inorganic N and P. The input of N and P via the deposition of coral spawn and associated phytodetritus resulted in large changes to N cycling in the sediments, but only small changes to P cycling, because of the buffering capacity provided by the large pool of bioavailable P. It is most likely that this large pool of bioavailable P in the sediments drives potential N limitation of benthic coral reef communities. For example, there was sufficient bioavailable P stored in the top 10 cm of the sediment column to sustain the prespawning rates of benthic production for over 200 d. Most of the change in benthic N cycling occurred via DON and N 2 pathways, driven by changes in the quantity and quality of organic matter deposited and decomposed post-major spawning. The heterotrophic and autotrophic microbial communities within the coral reef sands were able to rapidly (6 to 7 d) process the large episodic load of N and P provided by coral mass spawning.

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“…plankton, detritus) and source of inorganic nutrients (Capone et al 1992, Hatcher 1997, Rasheed et al 2002. The benthic mineralization is fuelled by particulate organic matter settling on the bottom, by benthic microalgae (Heil et al 2004), and by plankton trapped and mineralized by predominantly benthic heterotrophic suspension-feeding organisms, such as gorgonians, tunicates, and sponges (Buss & Jackson 1981, Pile 1999, Fabricius & Dommisse 2000, Wild et al 2004. Hotspots for plankton depletion and mineralization on coral reefs are cryptic habitats, such as crevices and coral cavities (Richter et al 2001, Scheffers et al 2004.…”

Section: Introductionmentioning

confidence: 99%

Why is bacterioplankton growth in coral reef framework cavities enhanced?

Scheffers¹,

Bak²,

Duyl³

2005

Mar. Ecol. Prog. Ser.

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Abundance, growth rates and nutrient limitation of the heterotrophic bacteria present in the reef water column and reef cavity water were measured on a fringing reef at Curaçao (Netherlands Antilles). Bacterial in situ growth rates were measured using dialysis bags. Nutrient limitation was measured using bioassays with different amendments of inorganic nutrients (nitrate, ammonium, phosphate) and dissolved organic carbon (glucose). Cell sizes were measured in the reef water column and over an intra-cavity gradient inside reef cavities, from the cavity center to the wall of the cavity. Bacterial abundance was lower in cavities, while growth rates were on average 3.6 times higher than in open reef water. The bacterial community in open reef water was limited in its growth by all nutrients, in contrast to cavity water, in which bacteria were limited by phosphate. Cell volumes decreased significantly from open reef water towards the cavity wall. Results suggest that conditions in cavities have a positive effect on bacterial growth. Growth limitation by N is alleviated through enhanced mineralization in cavities. Through rapid exchange with the ambient water, cavities enrich the overlying reef water with inorganic N.

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Benthic microalgae in coral reef sediments of the southern Great Barrier Reef, Australia

Cited by 39 publications

References 37 publications

Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia

Photosynthetic efficiency and rapid light curves of sediment-biofilms along a water quality gradient in the Great Barrier Reef, Australia

Mass coral spawning: A natural large‐scale nutrient addition experiment

Why is bacterioplankton growth in coral reef framework cavities enhanced?

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