Damselfish territories: zones of high productivity on coral reefs

Abstract

Temtories of 4 species of herbivorous damselfish from coral reefs of the central Great Barrier Reef and Motupore Island, Papua New Guinea were shown to be zones of high algal biomass and primary productivity relative to surrounding epilithic algal communities. Productivity was rneasured in the field from die1 patterns in oxygen flux, employing in situ data-logging respirometers. Algal communities inside territories were 1.6 to 3.4 times more productive per surface area than surrounding algal substrata. Algal communities of damselfish territories maintain a rate of productivity per unit biomass 1.5 to 3.4 times h g h e r than that of algae growing outside the territories. Differences in primary productivity for the 2 different types of algal community are due to the higher photosynthetic efficiency (0.37 to 0.94 pg O2 PE-') and potential maximum rate of photosynthesis (57 to 249 pg Oz cm-2 h-') of algae from territories compared with algae of non-territory areas (0.20 to 0.35 pg O2and 24 to 78 pg O2 cm-2 h-', respectively). Photosynthetic compensation and saturation irradiance were similar for the 2 algal communities and ranged from 52 to 100 and 337 to 735 PE m-' S-', respectively. These temtories are shown to be important to reef net productivity since they cover a high proportion of the reef flat zones examined (up to 77 O/O of substratum). Several hypotheses are proposed to account for the significantly higher rates of prlmary productivity inside coral reef damselfish territories compared wlth adjacent substrata.

Community structure, biomass and productivity of epilithic algal communities on the Great Barrier Reef: dynamics at different spatial scales

“…Measurements continued on consecutive days until 12 plates had been measured from each reef zone. Details on terminology, definitions and methodology for sample preparation; measurement of algal community structure (according to functional forms); biomass; and metabolism (dark respiration rate, photosynthesis-irradiance (P-I) relationships, die1 productivity); and data analysis are given in Klumpp et al (1987) and Klumpp & McKmnon (1989), and therefore are only sunlmarized here. The undersurface of coral plates were scraped in situ and transferred to the Perspex respirometer chambers.…”

“…The type and irregularity of the reef surface, at the sites where algal production was measured, were surveyed at Pandora, Myrmidon, Heron and One Tree Reefs in October 1989, and at MacGillivray and Yonge Reefs in December 1989. Reef surface type, expressed as proportional coverage by sand, and 7 functional groups of biota (as defined in Klumpp et al 1987): fine turf, damselfish-territory turf, crustose coralline algae, encrusting brown algae, macroalgae (e.g. Halimeda spp.…”

“…However, relatively little is known about the productivity of benthic plant communities on reef slopes and in deep lagoons. Epilithic algae are intensively grazed (Hatcher 1983, Carpenter 1986, Russ 1987, Klumpp & Polunin 1989, and in the process are maintained in a state of low biomass, but rapid turnover (Rogers & Salesky 1981, Carpenter 1985, Klumpp et. al.…”

Mercury (Hg) speciation in coral reef systems of remote Oceania: Implications for the artisanal fisheries of Tutuila, Samoa Islands

“…High accumulation factors for Hg in Tutuila turf algae are noteworthy because these algae, as the source of most primary production on the reef, are grazed extensively by a great variety of marine herbivores, with biomass turnover ~4-12 days (Carpenter, 1985;Klumpp et al, 1987). Magnification of Hg in turf algae of at the levels found here, consistent across three widely separated reef systems, appear remarkable given the ephemeral nature of turf algae on the reef, and indicate a highly efficient mechanism for Hg uptake from reef waters via the primary production pathway on coral reefs.…”

Hyperspectral Shallow-Water Remote Sensing with an Enhanced Benthic Classifier

“…This mode is exhibited by corals that appear pink, gray, purple and blue [28]. Turf Algae and Calcareous Algae dominate coverage on the reef flats and crests [32,33] and hence dominate the net primary production in these areas [34]. Turf Algae are a major food source by primary consumers [35,36], while Calcareous Algae (crustose coralline algae) precipitate calcium carbonate [37] and causes the cementation of the reef pavement which sustains the reef structure [38,39].…”