Figure 19 - uploaded by Robert Richmond
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1 (see color insert following page 464) Cross-section of coral colony with pink eggs and white spermaries.
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Black band disease (BBD) is one of the oldest recognized diseases of scleractinian corals. This disease is little known on the variation of progression rates across relatively small spatial scales and how local variations in the environment can impact prevalence and spread. The purpose of this study was to explore the progression of BBD on genus Mo...
Citations
... Reproduction and recruitment can be affected by both natural and anthropogenic stressors, the former often being exacerbated by the latter (e.g., Richmond 1997Richmond , 2005Fabricius 2005;Harrison 2011). The physiological state of a coral will determine the allocation of energy into various functions, including colony growth, tissue repair (when necessary), calcification, and reproduction. ...
Sexual reproductive activity has been demonstrated in all reef-building (zooxanthellate) scleractinian corals examined from Mexico to the equatorial eastern Pacific (Galápagos Islands). Eleven of 13 species spawn gametes, six are gonochoric, three hermaphroditic, and four exhibit significant mixed sexuality (both gonochoric and hermaphroditic). Four or 30.1 %, two species each of Pocillopora and Porites, produce autotrophic ova. Porites panamensis is the only known zooxanthellate brooder. Also sexually active are the azooxanthellate scleractinian Tubastraea coccinea and the zooxanthellate hydrocoral Millepora intricata. Reproductive structures, sex ratios, age at sexual maturity, sexuality, and developmental mode have been determined from largely histological evidence. Agariciid corals, comprising more than one-third of investigated species, exhibit predominantly mixed sexual systems with sequential cosexual hermaphroditic cycles in four species. Mixed sexuality is also minimally exhibited in populations of two dominantly gonochoric species. Several eastern Pacific corals spawn mostly on lunar day 17 and 1–2 days following; however, multispecific spawning has not been observed probably because of seasonal, diel, and variable timing in spawning behavior. Factors contributing to the high fecundity of eastern Pacific corals include (1) seasonally prolonged reproductive activity, (2) small size of mature gametes allowing for production of high numbers, (3) split spawning with bimonthly gamete production in some species, (4) alternation of sex maturation in gamete development, and possibly (5) their low latitudinal location under relatively constant and high thermal conditions. Coral community persistence, reef growth and recovery are highly dependent on both sexual and asexual reproductive processes. Asexual fragmentation by physical and biotic causes is particularly important, especially for branching pocilloporid species and the fungiid coral Diaseris distorta. Asexual propagation in massive and encrusting poritid and agariciid species is also common-place, often the result of bioerosion and colony breakage by foraging reef fishes. Some research areas in need of attention are noted, for example (a) timing of spawning and the behavior of gamete release of several species, (b) life cycles of Pocillopora spp. and Millepora intricata, and (c) effects of anthropogenic stressors on eastern Pacific coral reproduction and recruitment.
... Larvae were released from colonies during the night and collected in the morning each day. Once collected, larvae were kept in 10-L containers with UV-sterilized, 1-μm-filtered seawater at concentrations <1 larva ml −1 (Richmond 2005b) for 2-4 d until they were fully competent to settle. Daily water changes replaced approximately 75% of the volume of the larval holding tanks with a 125-μm mesh siphon to prevent larvae from being removed. ...
For degraded coral reef systems with limited larval supply, active restoration techniques may provide a means of replenishing adult coral populations. Settling or seeding large numbers of sexually-produced larvae directly onto denuded substrate is a potential restoration tool that can eliminate the costs associated with rearing coral spat in culturing facilities. However, the long-term potential to enhance recruitment using seeding techniques has generally been limited due to high post-settlement mortality. Using the brooding coral Porites astreoides (Lamarck, 1816), we explored two potential strategies—choosing favorable substrate communities and caging recently settled spat—to enhance early post-settlement survival during seeding efforts. Larvae were collected from adult colonies in the laboratory and, once competent to settle, were seeded directly onto the reef substrate. Settled spat were individually mapped and monitored using fluorescence techniques, and found to have a low survivorship with <3%–15% surviving after 1 mo, and <1% after 5 mo. Techniques to enhance survival, including choice of substrate and post-settlement caging, did not significantly influence the high rates of natural mortality. These results underscore the general lack of knowledge regarding the major factors that drive the magnitude of early post-settlement mortality, and future identification of these mortality factors may lead to suitable techniques to enhance survival in seeding efforts.
... Populations of P. damicornis depend on the settlement and recruitment of planula larvae during the juvenile polyp stage and these juvenile polyps later develop into mature corals (Permata et al., 2000). Recognizing these readily observable sensitivities, Goh (1991) and Richmond (2005) both suggest that scleractinian coral larvae make good test subjects for monitoring stress on coral reefs and are useful candidates for coral-reef ecotoxicology studies. ...
Biochemical and molecular biomarkers tools are utilized as early warning signatures of contaminant exposure to target and non-target organisms. The objective of this study was to investigate the sublethal effects of iron chloride to the larvae of the lace coral Pocillopora damicornis by measuring a suit of oxidative-stress biomarkers. The larvae were exposed to a range of sublethal concentrations of iron chloride (0.01, 0.1, 1, 10, and 100 ppm) for seven days. With reference to oxidative stress biomarkers, the no-observed effect concentration (NOEC) and the lowest observed effect concentration (LOEC) of iron chloride were observed to be 0.01 and 100 ppm respectively. At the end of the seventh day the antioxidant status of the larvae was evaluated by the levels of glutathione (GSH), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione-S-transferase (GST), in both experimental and control groups. For the quantification of cellular oxidative damage, lipid peroxidation (LPO) activity was determined in the same and the extent of DNA damage was assessed by the expression of DNA apurinic/apyrimidinic (AP) sites. Iron chloride exhibited a concentration-dependent inhibition of GSH and GPX and induction of GR, GST, LPO, and DNA-AP sites in the P. damicornis larvae when compared to the control group. The oxidative stress biomarkers of the larvae exposed to 0.1, 1, and 10 ppm of iron chloride did not show any significant overall differences when compared to the control group. However the activities of LPO, GSH, GPX, GR, GST and DNA-AP in the larval group exposed to 100 ppm of iron chloride exhibited statistically significant (P=0.002, 0.003, 0.002, 0.002, 0.005 and 0.007) differences when compared to the control group. The research results indicated that iron chloride in concentrations at the 100 ppm level caused oxidative stress in the P. damicornis larvae.
... Recruitment of coral larvae is essential to the replenishment of coral populations and survival of coral reefs. Coral larvae are extremely sensitive to environmental stressors and provide a good model for ecotoxicology testing (Richmond 2005). ...
... Pollutants may directly or indirectly affect coral larvae and metamorphic inducers associated with substrate (Richmond 2005). Metamorphic inducers send cues to coral larvae to settle and undergo metamorphosis (Harrington et al. 2004). ...
This study examined concentrations of Irgarol 1051(®) in selected marinas on the island of Oahu, Hawaii and used laboratory bioassays to assess effects of Irgarol on coral larval settlement. Field surveys of small boat marinas performed in 2006-2007 revealed low concentrations of Irgarol 1051(®), an antifouling paint additive, ranging from non-detected (<17 ng/l) to 283 ng/l. The highest concentrations of Irgarol 1051(®) were found in marinas with low flushing rates and a high density of moored boats and boat traffic. The potential effect of Irgarol 1051(®) on coral larval settlement was evaluated in the laboratory using planulae from Porites hawaiiensis, a zooxanthellate shade-dwelling coral found in Hawaiian waters. Exposure to Irgarol 1051(®) at 100 ng/l resulted in a statistically significant reduction in settlement of coral larvae. This was within the range of Irgarol 1051(®) concentrations found in some of the marinas surveyed on the island of Oahu but Irgarol was not detected in seawater samples at offshore reefs.
