Spatial, temporal and habitat-related variation in the abundance of large predatory fish at One Tree Reef, Australia

 Patterns of abundance of large piscivorous fish (>200 mm TL) were documented at two spatial and four temporal scales within the main lagoon of One Tree Reef on Australia’s Great Barrier Reef. Grouper (Serranidae), snapper (Lutjanidae) and wrasses (Labridae) were the most abundant large piscivores. On a large scale (hundreds of metres), patterns of predator abundance were consistently greater on the inner edge than centre of the lagoon over a range of temporal scales: days, weeks, months and years. On a small spatial scale (tens of metres), the abundance of large predatory fish was patchy. At both spatial scales, fish were consistently aggregated in particular areas and associated with specific structural features of the reef habitat. Predator abundance was high where live corals were predominant and the topography was more complex. Hence, predation pressure and its potential effects on the distribution and abundance of prey populations, both in time and space, may vary greatly within lagoonal environments. Accepted: 25 May 1997     

Effects of habitat isolation on pollinator communities and seed set

Destruction and fragmentation of natural habitats is the major reason for the decreasing biodiversity in the agricultural landscape. Loss of populations may negatively affect biotic interactions and ecosystem stability. Here we tested the hypothesis that habitat fragmentation affects bee populations and thereby disrupts plant-pollinator interactions. We experimentally established small ”habitat islands” of two self-incompatible, annual crucifers on eight calcareous grasslands and in the intensively managed agricultural landscape at increasing distances (up to 1000 m) from these species-rich grasslands to measure effects of isolation on both pollinator guilds and seed set, independently from patch size and density, resource availability and genetic erosion of plant populations. Each habitat island consisted of four pots each with one plant of mustard (Sinapis arvensis) and radish (Raphanus sativus). Increasing isolation of the small habitat islands resulted in both decreased abundance and species richness of flower-visiting bees (Hymenoptera: Apoidea). Mean body size of flower-visiting wild bees was larger on isolated than on nonisolated habitat islands emphasizing the positive correlation of body size and foraging distance. Abundance of flower-visiting honeybees depended on the distance from the nearest apiary. Abundance of other flower visitors such as hover flies did not change with increasing isolation. Number of seeds per fruit and per plant decreased significantly with increasing distance from the nearest grassland for both mustard and radish. Mean seed set per plant was halved at a distance of approximately 1000 m for mustard and at 250 m for radish. In accordance with expectations, seed set per plant was positively correlated with the number of flower-visiting bees. We found no evidence for resource limitation in the case of mustard and only marginal effects for radish. We conclude that habitat connectivity is essential to maintain not only abundant and diverse bee communities, but also plant-pollinator interactions in economically important crops and endangered wild plants. Received: 7 May 1999 / Accepted: 19 July 1999     

Territorial damselfish enhances multi-species co-existence of foraminifera mediated by biotic habitat structuring

The structures of benthic foraminiferal communities inside and outside the territory of the pomacentrid damselfish Stegastes nigricans on coral rocks in a moat of Sesoko Is. (26°38′N, 127°52′E) in Okinawa, Japan were compared. Inside the territory, an algal farm, i.e., a dense stand of a filamentous rhodophyte, Womersleyella setacea, was maintained throughout the year. Outside the territory, in areas subjected to intensive and continuous grazing by various grazers, the flora was composed of mat-like cyanophytes, a prostrate turf-form Padina sp., microscopically thin filaments and scattered filamentous rhodophytes. Algal biomass was greater inside the territory than outside the territory of the damselfish. These differences were reflected by the structure of the associated foraminiferal communities. We classified foraminiferal species based on their microhabitat use around algal communities into four life types: free-living type, crawling type, sedentary type, and sessile type. The abundance of foraminifera, especially the free-living type (e.g., Peneroplis pertusus and Quinqueloculina seminulum) and sedentary type (Rosalina globularis and Cymbaloporetta squammosa), was greater inside the territory of the damselfish than outside the territory. Species richness was also higher inside the territory, mainly due to an increase in species richness of the free-living and sedentary types. These increases in abundance and species richness were caused by habitat structuring. W. setacea is a relatively tall and complicated alga with tangled rhizoids. Its dense stand inside the territory trapped a larger amount of sediment, which provided free-living foraminifera with heterogeneous and stable habitats. In addition, the dense stand of W. setacea provided sedentary-type foraminifera with a large, complex substratum, providing refuge and food inside the territory. This assumption was confirmed by the results of plate experiments showing that foraminiferal community structures were controlled by associations between foraminifera and algae. We showed that habitat-conditioning is an important process in biotic habitat-structuring and that habitat-conditioning by territorial damselfish maintains and enhances multi-species coexistence of foraminifera on coral rocks in a coral reef.     

Habitat associations of juvenile versus adult butterflyfishes

Many coral reef fishes exhibit distinct ontogenetic shifts in habitat use while some species settle directly in adult habitats, but there is not any general explanation to account for these differences in settlement strategies among coral reef fishes. This study compared distribution patterns and habitat associations of juvenile (young of the year) butterflyfishes to those of adult conspecifics. Three species, Chaetodon auriga, Chaetodon melannotus, and Chaetodon vagabundus, all of which have limited reliance on coral for food, exhibited marked differences in habitat association of juvenile versus adult individuals. Juveniles of these species were consistently found in shallow-water habitats, whereas adult conspecifics were widely distributed throughout a range of habitats. Juveniles of seven other species (Chaetodon aureofasciatus, Chaetodon baronessa, Chaetodon citrinellus, Chaetodon lunulatus, Chaetodon plebeius, Chaetodon rainfordi, and Chaetodon trifascialis), all of which feed predominantly on live corals, settled directly into habitat occupied by adult conspecifics. Butterflyfishes with strong reliance on corals appear to be constrained to settle in habitats that provide access to essential prey resources, precluding their use of distinct juvenile habitats. More generalist butterflyfishes, however, appear to utilize distinct juvenile habitats and exhibit marked differences in the distribution of juveniles versus adults.     

Interactive effects of habitat selection, food supply and predation on recruitment of an estuarine fish

 Seagrass meadows are often important habitats for newly recruited juvenile fishes. Although substantial effort has gone into documenting patterns of association of fishes with attributes of seagrass beds, experimental investigations of why fish use seagrass habitats are rare. We performed two short-term manipulative field experiments to test (1) the effects of food supply on growth and densities of fish, and (2) effects of predation on the density and size distribution of fish recruits, and how this varies among habitat types. Experiments were conducted in Galveston Bay, Texas, and we focused on the common estuarine fish, pinfish Lagodon rhomboides. In the first experiment, replicate artifical seagrass and sand plots were either supplemented with food or left as controls. Recruitment of pinfish was significantly greater to seagrass than sand habitats; however, we detected no effect of food supplementation on the abundance of recruits in either habitat. Pinfish recruits in artifical seagrass grew at a significantly faster rate than those in sand habitats, and fish supplemented with food exhibited a greater growth rate than controls in both sand and artifical grass habitats. In our second experiment, we provided artificial seagrass and sand habitats with and without predator access. Predator access was manipulated with cages, and two-sided cages served as controls. Recruitment was significantly greater to the cage versus cage-control treatment, and this effect did not vary between habitats. In addition, the standard length of pinfish recruits was significantly larger in the predator access than in the predator exclusion treatment, suggesting size-selective predation on smaller settlers or density-dependent growth. Our results indicate that the impact of predation on pinfish recruits is equivalent in both sand and vegetated habitats, and thus differential predation does not explain the higher recruitment of pinfish to vegetated than to nonvegetated habitats. Since predators may disproportionately affect smaller fish, and a limited food resource appears to be more effectively utilized by fish in vegetated than in unvegetated habitats, we hypothesize that pinfish recruits may select vegetated habitats because high growth rates allow them to achieve a size that is relatively safe from predation more quickly. Received: 10 October 1996 / Accepted: 5 April 1997     

Food availability affects growth in a coral reef fish

Summary Pomacentrus amboinensis is common on small patch reefs within One Tree Lagoon (Great Barrier Reef), where it preferentially settles onto deep reefs. A preliminary experiment, in which juveniles were transplanted to identical reef structures at two sites, within two depth strata, indicated that juvenile growth and survivorship were better in deeper water. The hypothesis that this difference was due to food availability was tested by a supplemental feeding experiment, carried out at another two randomly chosen sites, within the same two depth strata. Fish were fed each day over a one month period, during which no mortality was observed. The growth rates of juveniles were markedly higher on all food-supplemented reefs, when compared to controls. Growth differed between depth strata, but there was no interaction between the food x depth factors, which would have suggested a greater effect of food supplementation in either habitat. Thus, although the difference between depths cannot be attributed to food availability, the results have a more general significance. Food appears to be a limiting resource (in terms of growth) in both the marginal shallow habitat, and the more suitable deeper habitat.     

Habitat selection by recruits establishes local patterns of adult distribution in two species of damselfishes: Stegastes dorsopunicans and S. planifrons

Local patterns of adult distribution in organisms that disperse young as pelagic larvae can be determined at the time of recruitment through habitat selection or, shortly thereafter, through post-recruitment processes such as differential juvenile survivorship and interspecific competition. This study addresses the importance of habitat selection by recruits in establishing the local pattern of adult distribution in two sympatric Caribbean damselfish species, Stegastes dorsopunicans and S. planifrons. Both species inhabit shallow reefs but show little overlap in their distribution; S. dorsopunicans predominates in the reef crest and S. planifrons occurs primarily on the reef slope. Furthermore, S. dorsopunicans is associated with rocky substrate, while S. planifrons occupies live coral. The substrate cover follows a similar pattern with coral being much less common on the reef crest than on the reef slope. Monitoring recruitment every other day in reciprocal removal experiments and artificial reefs indicates that the observed pattern of local adult distribution is a product of habitat selection for both species. The presence or absence of conspecifics did not influence recruitment patterns for either species. Stegastes dorsopunicans recruited primarily to shallow, rocky areas, appearing to cue on both substratum type and depth. Stegastes planifrons recruited exclusively to coral substratum independent of depth. These results indicate that local adult patterns of distribution can be explained by habitat selection at recruitment, and that substrate type and depth may be important cues. Received: 27 May 1997 / Accepted: 4 January 1998     

An appraisal of methods used in coral recruitment studies

 A new method for attaching individual artificial settlement plates directly to the reef surface using small stainless steel base plates is described. Recruitment of corals to settlement plates attached to the reef substratum and to steel mesh racks is compared. The effects of differences in depth, settlement plate angle, and local topography on recruitment of corals were also investigated. No significant difference in mean recruit density was found between settlement plates deployed using the two attachment methods. Small differences in depth and plate angle among replicate plates explained less than 6% of the variability in coral recruitment on replicate settlement plates. The direct-attachment method is less obtrusive, more cost and time efficient, and settlement plates can be deployed at precise locations. Additionally, because settlement plates are deployed individually rather than grouped on racks or frames, the direct-attachment method avoids complications associated with assumptions of independence implicit in most statistical procedures. Accepted: 24 November 1999     

Molecular cloning and expression of long-wavelength-sensitive cone opsin in the brain of a tropical damselfish

Ovarian development of the sapphire devil, Chrysiptera cyanea, exhibits photoperiodism and is stimulated under long-day conditions. Previous studies suggest that red light is more effective than green and blue lights for inducing ovarian development. In addition, the extra-retinal photoreception involved in the ovarian development is suggested in this species. The present study aimed to clone the red-light-sensitive cone opsin (sdLWS) of this species, to demonstrate its expression in the brain, and to confirm the effectiveness of red light on the initiation of ovarian development. A phylogenetic analysis revealed that sdLWS belongs to the long-wavelength-sensitive opsin (LWS opsin) group, showing high identity (77–92%) with the LWS opsin of other fishes. RT-PCR showed that sdLWS is expressed in the eye, brain, and ovary. In situ hybridization indicated that sdLWS is expressed in the third ventricle periventricular area in the anterior hypothalamus. Exposing fish to long-day conditions of red light resulted in the appearance of vitellogenic oocytes in the ovary and an increase in the gonadosomatic index within 2 weeks, suggesting that fish immediately undergo oocyte development under red light conditions. These results indicate that sdLWS is a possible candidate of deep brain photoreceptor molecule involved in photoperiodic ovarian development in the sapphire devil.     

How does shoreline development impact the recruitment patterns of coral reef fish juveniles (Moorea Island,French Polynesia)?

The study examined the effects of coastal embankment building on fish recruitment in three habitat types (beach-rock, white sand and muddy sand) in the near shore and fringing reef habitats of Moorea lagoon (French Polynesia). The results showed a positive relationship between the presence of embankments and the density and species richness of juvenile fish along the shoreline (whatever the habitat types). However, embankments deteriorated adjacent fringing reefs (decrease of live coral), which led to a decrease of fish density on beach-rock and white sand sites, and a decrease of fish species richness on muddy sand sites.     

Coral growth in subtropical eastern Australia

 Extension rates of corals at two sites in subtropical eastern Australia (Solitary Islands and Lord Howe Island) were measured to determine whether growth was low relative to tropical locations. Growth was measured using alizarin staining of skeletons and X-radiographic analysis, and was compared between colonies, species, and sites. Linear extension of individual Pocillopora damicornis colonies averaged 12.4 to 16.1 mm per year at Solitary Islands and Lord Howe Island respectively, which is 50% to 80% of published values for this species at tropical sites. Similarly, average extension of most massive faviid species examined at these sites was between 2.6 mm and 4.6 mm per year, considerably lower than most values reported from lower latitudes (generally 6 mm to 10 mm per year). However, growth rates of Acropora yongei, Turbinaria frondens, and Porites heronensis were close to those of closely-related taxa from the tropics. Causal links between latitude, growth rates of coral colonies, and the potential for reef accretion remain unclear. Accepted: 22 April 1999     

Predicting reef fish connectivity from biogeographic patterns and larval dispersal modelling to inform the development of marine reserve networks

Developing networks of no-take marine reserves is often hindered by uncertainty in the extent to which local marine populations are connected to one another through larval dispersal and recruitment (connectivity). While patterns of connectivity can be predicted by larval dispersal models and validated by empirical methods, biogeographic approaches have rarely been used to investigate connectivity at spatial scales relevant to reserve networks (10's–100's of km). Here, species assemblage patterns in coral reef fish were used together with an individual-based model of dispersal of reef fish larvae to infer patterns of connectivity in a ∼300 km wide region in the Philippines that included the Bohol Sea and adjacent bodies of water. A dominant current flows through the study region, which may facilitate connectivity among >100 no-take reserves. Connectivity was first investigated by analysing data on the presence/absence of 216 species of reef fish and habitat variables across 61 sites. Hierarchical clustering of sites reflecting species assemblage patterns distinguished a major group of sites in the Bohol Sea (Bray–Curtis similarity >70%) from sites situated in adjacent bodies of water (bays, channels between islands and a local sea). The grouping of sites could be partly explained by a combination of degree of embayment, % cover of sand and % cover of rubble (Spearman rank correlation, ρ_w = 0.42). The individual-based model simulated dispersal of reef fish larvae monthly for three consecutive years in the region. The results of simulations, using a range of pelagic larval durations (15–45 days), were consistent with the species assemblage patterns. Sites in the model that showed strongest potential connectivity corresponded to the majority of sites that comprised the Bohol Sea group suggested by hierarchical clustering. Most sites in the model that exhibited weak connectivity were groups of sites which had fish assemblages that were least similar to those in the Bohol Sea group. Concurrent findings from the two approaches suggest a strong influence of local oceanography and geography on broad spatial patterns of connectivity. The predictions can be used as an initial basis to organise existing reserves to form ecologically meaningful networks. This study showed that species assemblage patterns could be a viable supplementary indicator of connectivity if used together with predictions from a larval dispersal model and if the potential effect of habitat on the structuring of species assemblages is taken into consideration.     

Incorporating fine-scale seascape composition in an assessment of habitat quality for the giant sea anemone Stichodactyla gigantea in a coral reef shore zone

Habitat loss due to land reclamation often occurs in sandy coral reef shore zones. The giant sea anemone Stichodactyla gigantea, which harbors the false clown anemonefish Amphiprion ocellaris, both of which are potentially flagship species, inhabit these places. To assess habitat quality for S. gigantea, we examined correlative associations between the number and the body size of S. gigantea and the amount of habitat types in fine-scale seascape composition quantified from an enlarged section of a high-resolution (1/2,500) color aerial photograph of the shallow shore zone of Shiraho Reef, Ishigaki Island, Japan. This study confirmed that anemones were most abundant at the edges of dense seagrass beds characterized by shallow sandy bottoms, rock beds, and sparse seagrass beds, while they were less abundant in coral patch reefs. However, anemones inhabiting coral patch reefs were significantly larger and their rate of disappearance over 3 years was lower than those inhabiting other habitats. This suggests that coral patch reefs may be more suitable habitats supporting larger animals and greater persistence of S. gigantea. The visual census techniques applied here, combined with aerial photography and image-analysis software, may be useful as a simple analytical tool for local assessment of suitable habitats for relatively small-bodied marine fauna in shallow-water seascapes.     

Spatial study of juvenile corals in the Northern region of the Mesoamerican Barrier Reef System (MBRS)

Juvenile coral abundance and community composition depend on the spatial scale studied. To investigate this, an evaluation was made of juvenile coral density with hierarchical spatial analysis in the northern Mesoamerican Barrier Reef System (MBRS) at ~10 m depth. Study scope included semi-protected and unprotected areas located in this region. A total of 19 juvenile coral taxa were found, including 10 scleractinian species, 8 scleractinian coral genera not identified to species, and 1 Millepora species (Hydrozoa-Milleporidae). In terms of relative abundance, Agaricia spp., Siderastrea spp., and Porites spp. were the main juvenile taxa in the coral community at the surveyed sites, reefs, and regions levels. Greater variance was seen at smaller scales, at site level for taxa richness, and at the transect level for juvenile density, and lower variance was seen at larger scales (reefs and regions). The variance component contribution from each scale likely differed from other studies because of the different factors affecting the community and the different extensions of each scale used in each study. Densities (1–6.4 juvenile corals/m²) and dominant taxa found in this study agree with other studies from the Western Atlantic. Detected variability was explained by different causal agents, such as low grazing rates by herbivorous organisms, turbidity, and/or sediment suffocation and some nearby or distant localized disturbance (human settlement and a hurricane).     

Macroborers within coral framework at Discovery Bay, north Jamaica: species distribution and abundance, and effects on coral preservation

 Macroboring organisms are recognised as key agents of reef framework modification and destruction, and while recent studies in the Pacific have improved understanding of spatial variations in macroboring community structure, and rates of macroboring within individual reefs, comparable studies from the Caribbean are largely lacking. This study assesses the distribution of macroboring species and the degree of framework infestation across the reefs at Discovery Bay, north Jamaica. Although individual species of borers exhibit variable distributions across the reef, relative abundances of the main groups of macroborers (sponges, bivalves, worms) illustrate clear distributional trends. Sponges are dominant at fore-reef sites, while sipunculan and polychaete worms are only of importance at back-reef/lagoon and shallow fore-reef sites. Bivalves are locally important within back-reef and lagoon patch reef framework. Average percentages of internal bioerosion (macroboring) vary between sites, but are highest at back-reef and deep fore-reef sites. No systematic pattern of variation occurs within back-reef/lagoon samples, but a significant trend of increased macroboring is recognised with increased water depth on the fore-reef. In addition, significant differences in terms of the susceptibility of individual coral species are recognised. These factors are likely to result in biasing of the fossil record, with variable styles of preservation evident both between sites (i.e. with depth/environment) and within sites (i.e. between coral species). Accepted: 1 June 1998     

Food ration and condition affect early survival of the coral reef damselfish, Stegastes partitus

The supply of larvae is a major determinant of population and community structure in coral reef fishes. However, spatial and temporal variation in condition (i.e. quality) of potential recruits, as well as their density (i.e. quantity), may influence survival and growth of juveniles. We conducted an experiment to test whether recent feeding history could affect growth, condition and post-recruitment survival in a Caribbean damselfish, Stegastes partitus. Fish were collected soon after settlement, and fed either low or high rations in aquaria for 7 days. Fish fed the high ration grew faster in aquaria and were in a better condition (higher total lipids and Fulton’s condition factor) at the end of the feeding period. Subsequently, we released 50 fish in 25 pairs (one fish subjected to low rations, the other to high rations) on a Bahamian coral reef and monitored survival for 10 days. Survivorship of high-ration fish was double that of low-ration fish (80 vs 40% over 10 days). However, low-ration fish that survived 10 days were of similar condition and grew at similar rates to high-ration fish, suggesting that short-term ration differences may not persist in surviving fish. Laboratory experiments showed that low-ration fish were taken by piscivorous fishes before high-ration fish, indicating that differential predation may account for survival differences. This study highlights the potential of feeding history and condition to affect the relationship between patterns of larval arrival at reefs, and subsequent juvenile and adult population densities. Received: 1 March 1999 / Accepted: 15 July 1999     

The effect of habitat fragmentation on dispersal patterns, mating behavior, and genetic variation in a pika (Ochotona princeps) metapopulation

 Habitat fragmentation is becoming increasingly common, yet, the effect of habitat spatial structure on population dynamics remains undetermined for most species. Populations of a single species found in fragmented and nonfragmented habitat present a rare opportunity to examine the effect of habitat spatial structure on population dynamics. This study investigates the impact of highly fragmented habitat on dispersal patterns, mating behavior, and genetic variation in a pika (Ochotona princeps) population with a mainland-island spatial structure. Juvenile dispersal patterns in fragmented habitat revealed that individuals tended to disperse to neighboring habitat patches. However, within-patch band-sharing scores from multilocus DNA fingerprints did not differ from what would be expected if individuals were assorting randomly among habitat patches each year. Multiple, short-distance dispersal targets for juveniles and occasional long-distance dispersal events suggest that habitat fragmentation on this scale has not resulted in restricted dispersal and a genetically subdivided population. Although pikas tended to mate with the closest available partner, DNA fingerprinting band-sharing scores between mated pairs were consistent with a random mating hypothesis. Random mating in this population appears to be an incidental effect of dispersal in a fragmented habitat. This pattern is distinct from that found in nonfragmented habitat (large talus patches) where mating was non-random and consistent with mating between individuals of intermediate relatedness. DNA fingerprinting data revealed within-species variation in the mating habits of the pika directly attributable to habitat spatial structure. Received: 4 November 1996 / Accepted: 30 June 1997     

The effects of plant dispersion and prey density on parasitism rates in a naturally patchy habitat

Despite extensive research on parasitoid-prey interactions and especially the effects of heterogeneity in parasitism on stability, sources of heterogeneity other than prey density have been little investigated. This research examines parasitism rates by three parasitoid species in relationship to prey density and habitat spatial pattern. The herbivore Itame andersoni (Geometridae) inhabits a subdivided habitat created by patches of its host plant, Dryas drummondii, in the Wrangell Mountains of Alaska. Dryas colonizes glacial moraines and spreads clonally to form distinct patches. Habitat subdivision occurs both on the patch scale and on the larger spatial scale of sites due to patchy successional patterns. Itame is attacked by three parasitoids: an ichneumonid wasp (Campoletis sp.), a braconid wasp (Aleiodes n. sp.), and the tachinid fly (Phyrxe pecosensis). I performed a large survey study at five distinct sites and censused Itame density and parasitism rates in 206 plant patches for 1–3 years. Parasitism rates varied with both plant patch size and isolation and also between sites, and the highest rates of overall parasitism were in the smallest patches. However, the effects of both small- and large-scale heterogeneity on parasitism differed for the three parasitoid species. There was weak evidence that Itame density was positively correlated with parasitism for the braconid and tachinid at the patch scale, but density effects differed for different patch sizes, patch isolations, and sites. At the site scale, there was no evidence of positive, but some indication of negative density-dependent parasitism. These patterns do not appear to be driven by negative interactions between the three parasitoid species, but reflect, rather, individual differences in habitat use and response to prey density. Finally, there was no evidence that parasitism strongly impacted the population dynamics of Itame. These results demonstrate the importance of considering habitat pattern when examining spatial heterogeneity of parasitism and the impacts of parasitoids. Received: 3 June 1999 / Accepted: 4 October 1999     

Direct measurements of carbon and carbonate export from a coral reef ecosystem (Moorea Island , French Polynesia)

The export of carbon and carbonate from coral reefs was investigated through a multidisciplinary investigation of the hydrological, geochemical, sedimentological and biological features of Tiahura reef on the northwestern coast of Moorea Island (French Polynesia). The hydrology of the fore-reef is characterised by prevailing longshore western currents and a strong thermocline. As revealed by turbidity structures (benthic and intermediate nepheloid layers) and by the amount of particles collected by near-bottom sediment traps, horizontal and downslope advections of particles dominate over offshore vertical transport. The exported material is rich in carbonate (ca. 80%) and poor in organic matter (ca. 4%). Sedimentation rates at 430 m depth, i.e. definitive export, reached 209.6 mg m^-2 d^-1 (dry weight). Estimates of carbon and carbonates export for Tiahura reef also reported here represent respectively 47% and 21% of the organic and inorganic carbon produced within the reef.