michaelg January 24, 2005 Share January 24, 2005 Importance of a micro-diet for scleractinian corals Houlbreque F, Tambutte E, Richard C, Ferrier-Pages C MARINE ECOLOGY-PROGRESS SERIES 282: 151-160 2004 Document type: Article Language: English Cited References: 85 Times Cited: 0 Explanation Abstract: This study investigated the ability of 3 coral species - zooxanthellate (Stylophora pistillata and Galaxea fascicularis) and azooxanthellate (Tubastrea aurea)-to feed on pico- and nano-plankton (particles < 100 mum). Coral nubbins were incubated for 6 h in flow chambers containing the planktonic particles (experimental chambers). Control chambers were also set up to follow the natural changes in the planktonic community. Changes in the concentrations of dissolved organic carbon (DOC), bacteria, cyanobacteria and flagellates were monitored during the incubation. Results showed that ingestion rates were proportional to prey concentrations. In terms of number of prey ingested per polyp, bacteria were the first group ingested. When converted into carbon and nitrogen, nanoflagellates represented the most important contribution, amounting to 84-94 % of the total carbon and 52-85% of the total nitrogen ingested. Bacteria, cyanobacteria and picoflagellates accounted only for 1-7 % of the ingested carbon. At the end of the incubation, DOC concentrations increased in the chambers containing T. aurea and G. fascicularis. However, in all chambers containing S. pistillata, DOC concentrations decreased (from 101.69 +/- 13.53 to 93.59 +/- 4.67 mumol DOC1(-1)) equal to a rate of 0.251 +/- 0.217 nmol DOC polyp(-1) h(-1). In symbiotic species, pico- and nanoplankton accounted for only 6.6-7.8 % of the carbon supplied by photosynthesis but were a major supply of nitrogen. In S. pistillata, the amount of nitrogen supplied by pico- and nanoplankton ingestion (1.2 ng N polyp(-1) h(-1)) was as high as the amount supplied by the dissolved nitrogen uptake (1.55 ng N polyp(-1) h(-1)). Pico- and nanoplankton may, therefore, constitute an important food source for these corals. Author Keywords: scleractinian corals, heterotrophy, grazing rates, picoplankton, nanoplankton, DOC, DON KeyWords Plus: BENTHIC SUSPENSION FEEDERS, DISSOLVED ORGANIC-CARBON, ATLANTIC TIME-SERIES, GREAT-BARRIER-REEF, STYLOPHORA-PISTILLATA, PREY CAPTURE, MADRACIS-MIRABILIS, PARTICLE CAPTURE, POCILLOPORA-DAMICORNIS, GALAXEA-FASCICULARIS Addresses: Houlbreque F, Ctr Sci Monaco, Ave St Martin, MC-98000 Monaco, Monaco Ctr Sci Monaco, MC-98000 Monaco, Monaco Publisher: INTER-RESEARCH, NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY IDS Number: 880LS ISSN: 0171-8630 Link to comment Share on other sites More sharing options...
michaelg January 24, 2005 Author Share January 24, 2005 Sweeper tentacles of the brain coral Platygyra daedalea: induced development and effects on competitors Lapid ED, Wielgus J, Chadwick-Furman NE MARINE ECOLOGY-PROGRESS SERIES 282: 161-171 2004 Document type: Article Language: English Cited References: 37 Times Cited: 0 Explanation Abstract: Benthic marine organisms utilize an array of defensive and aggressive mechanisms that affect competition for space on hard marine substrata, The sweeper tentacles of stony corals are inducible aggressive organs used during competition, but they also may serve a pre-emptive defensive function. About half of the colonies of the brain coral Platygyra daedalea at Eilat, northern Red Sea, possess sweeper tentacles, many of which are not directed toward neighboring corals. These randomly oriented sweeper tentacles may be produced in order to detect the settlement or advance of corals occurring at >5 cm distance from the colony. Of coral colonies <5 cm distant from P. daedalea, about 43% exhibit tissue damage facing the interaction area. Adjacent corals with the most damage belong to the genera Favites and Leptastrea, while colonies of Millepora and congeneric Platygyra exhibit significantly less damage. Tissue damage of neighboring coral colonies decreases significantly with increasing distance from P. daedalea. The presence of sweeper tentacles on brain corals correlates significantly with colony diameter, but not with the number of neighboring colonies. The aggressive reach of P daedalea in Eilat is 5.3 +/- 3.0 cm, longer than previously reported for members of this genus. Under laboratory conditions, sweeper tentacles develop on P. daedalea colonies about 30 d following initial contact with colonies of the common massive coral F. complanata, and at approximately 50 d they reach a maximum length of about 6.5 cm, 10x longer than feeding tentacles. Sweeper tentacles cause increasing tissue damage to F. complanata colonies over 2 mo. During morphogenesis, their tip-to-stalk ratio and ectoderm thickness doubles, indicating acrosphere development, but maximal width of the tentacle stalk does not change. Sweeper tentacles appear to be a common agonistic mechanism among stony corals, and may serve also as a defensive mechanism that allows the persistence of some species in crowded reef habitats. Author Keywords: competition, reef coral, aggression, defense, behavior, Eilat, Red Sea KeyWords Plus: INTERSPECIFIC AGGRESSION, REEF CORALS, SCLERACTINIAN CORALS, RED-SEA, EILAT, SPACE Addresses: Chadwick-Furman NE, Auburn Univ, Dept Sci Biol, 101 Rouse Life Sci Bldg, Auburn, AL 36849 USA Bar Ilan Univ, Fac Life Sci, Ramat Gan, Israel Interuniv Inst Marine Sci, Elat, Israel Publisher: INTER-RESEARCH, NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY IDS Number: 880LS ISSN: 0171-8630 Link to comment Share on other sites More sharing options...
michaelg January 24, 2005 Author Share January 24, 2005 Habitat use by sponge-dwelling brittlestars Henkel TP, Pawlik JR MARINE BIOLOGY 146 (2): 301-313 JAN 2005 Document type: Article Language: English Cited References: 49 Times Cited: 0 Explanation Abstract: Cryptic organisms often associate with sessile invertebrates for refuge in space-limited environments. To examine interspecific habitat associations on coral reefs, tube- and vase-shaped sponges were surveyed for associated brittlestars at six sites on the coral reefs off Key Largo, Florida. Of 179 sponges encountered, Callyspongia vaginalis was the most abundant (43.0%), followed by Niphates digitalis (39.7%), and Callyspongia plicifera (4.5%). Three of eight sponge species surveyed did not differ from C. vaginalis in two physical refuge characteristics: oscular diameter and inner tube surface area. Brittlestars (416 total), all of the genus Ophiothrix, were only found in C. vaginalis, N. digitalis, and C. plicifera. The most abundant brittlestar, O. lineata (326), occurred on C. vaginalis (99.0%) and N. digitalis (1.0%), while O. suensonii (67) occurred on C. vaginalis (79.1%), N. digitalis (19.4%), and C. plicifera (1.5%). There was no pattern of co-occurrence of O. lineata and O. suensonii on C. vaginalis. The abundance of O. lineata increased with surface area of C. vaginalis. Differential habitat use was observed in O. lineata, with small individuals (<5 mm disk diameter) located inside and on the surface of sponge tubes and large individuals (greater than or equal to5 mm) solely inside tubes. The number of large O. lineata in C. vaginalis never exceeded the number of tubes per sponge, and tagged O. lineata remained in the same sponge for at least 3 weeks. In density manipulations, no pattern of intraspecific competition among large O. lineata was observed; however, there was evidence for interaction between size-classes. Brittlestars selected live sponge habitat over a non-living refuge, suggesting a mechanism for sponge habitat recognition. Sponge-dwelling brittle stars prefer some tube- and vase-shaped sponge species despite similar oscular diameters and surface areas. Surprisingly, these preferred sponge species are known from previous studies to be chemically undefended against generalist fish predators; therefore, brittlestars that inhabit these sponges do not gain an associational chemical defense. Sponge habitat use by O. lineata may be governed by intraspecific interactions to maintain habitat and access to food. While past studies have suggested that O. lineata is an obligate sponge commensal, the present study suggests that O. lineata has a species-specific association with the tube-sponge C. vaginalis. KeyWords Plus: CHEMICAL DEFENSE, PATTERNS, OPHIUROIDEA, ECOLOGY, FISHES, GUILD, SIZE, ARCHITECTURE, COMMUNITIES, RECRUITMENT Addresses: Pawlik JR, Univ N Carolina, Ctr Marine Sci, 5600 Masonboro Loop Rd, Wilmington, NC 28409 USA Univ N Carolina, Ctr Marine Sci, Wilmington, NC 28409 USA Publisher: SPRINGER, 233 SPRING STREET, NEW YORK, NY 10013 USA IDS Number: 881YP ISSN: 0025-3162 Link to comment Share on other sites More sharing options...
michaelg January 24, 2005 Author Share January 24, 2005 Is photoinhibition of zooxanthellae photosynthesis the primary cause of thermal bleaching in corals? Smith DJ, Suggett DJ, Baker NR GLOBAL CHANGE BIOLOGY 11 (1): 1-11 JAN 2005 Document type: Review Language: English Cited References: 105 Times Cited: 0 Explanation Abstract: The bleaching of corals in response to increases in temperature has resulted in significant coral reef degradation in many tropical marine ecosystems. This bleaching has frequently been attributed to photoinhibition of photosynthetic electron transport and the consequent photodamage to photosystem II (PSII) and the production of damaging reactive oxygen species (ROS) in the zooxanthellae (Symbiodinium spp.). However, these events may be because of perturbations of other processes occurring within the zooxanthellae or the host cells, and consequently constitute only secondary responses to temperature increase. The processes involved with the onset of photoinhibition of electron transport, photodamage to PSII and pigment bleaching in coral zooxanthellae are reviewed. Consideration is given to how increases in temperature might lead to perturbations of metabolic processes in the zooxanthellae and/or their host cells, which could trigger events leading to bleaching. It is concluded that production of ROS by the thylakoid photosynthetic apparatus in the zooxanthellae plays a major role in the onset of bleaching resulting from photoinhibition of photosynthesis, although it is not clear which particular ROS are involved. It is suggested that hydrogen peroxide generated in the zooxanthellae may have a signalling role in triggering the mechanisms that result in expulsion of zooxanthellae from corals. Author Keywords: bleaching, corals, hydrogen peroxide, photoinhibition, photosynthesis, reactive oxygen species, singlet oxygen, zooxanthellae KeyWords Plus: DINOFLAGELLATE SYMBIODINIUM-MICROADRIATICUM, SOLAR ULTRAVIOLET-RADIATION, INORGANIC CARBON UPTAKE, REEF CORALS, OXIDATIVE STRESS, HEAT-STRESS, STYLOPHORA-PISTILLATA, HYDROGEN-PEROXIDE, GONIASTREA-ASPERA, RUBISCO ACTIVASE Addresses: Baker NR, Univ Essex, Coral Reef Res Unit, Dept Biol Sci, Colchester CO4 3SQ, Essex, England Univ Essex, Coral Reef Res Unit, Dept Biol Sci, Colchester CO4 3SQ, Essex, England Publisher: BLACKWELL PUBLISHING LTD, 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND IDS Number: 880LM ISSN: 1354-1013 Link to comment Share on other sites More sharing options...
michaelg January 24, 2005 Author Share January 24, 2005 Distribution of magnesium in coral skeleton Meibom A, Cuif JP, Hillion FO, Constantz BR, Juillet-Leclerc A, Dauphin Y, Watanabe T, Dunbar RB GEOPHYSICAL RESEARCH LETTERS 31 (23): Art. No. L23306 DEC 11 2004 Document type: Article Language: English Cited References: 32 Times Cited: 0 Explanation Abstract: Ion micro-probe imaging of the aragonite skeleton of Pavona clavus, a massive reef-building coral, shows that magnesium and strontium are distributed very differently. In contrast to strontium, the distribution of magnesium is strongly correlated with the fine-scale structure of the skeleton and corresponds to the layered organization of aragonite fibers surrounding the centers of calcification, which have up to ten times higher magnesium concentration. This indicates a strong biological control over the magnesium composition of all structural components within the skeleton. Magnesium may be used by the coral to actively control the growth of the different skeletal crystal components. KeyWords Plus: AMORPHOUS CALCIUM-CARBONATE, SCLERACTINIAN CORAL, GROWTH, THERMOMETRY, BINDING, PHASE, MG/CA Addresses: Meibom A, Stanford Univ, Dept Geol & Environm Sci, 320 Lomita Mall, Stanford, CA 94305 USA Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA Fac Sci, Geol UMR IDES, F-91405 Orsay, France Cameca SA, F-92403 Courbevoie, France Stanford Univ, Biomech Engn Div, Stanford, CA 94305 USA CEA, CNRS, Lab Sci Climat & Environm, F-91198 Gif Sur Yvette, France Publisher: AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA IDS Number: 881PE ISSN: 0094-8276 Link to comment Share on other sites More sharing options...
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