The phenomenon of coral fluorescence in mesophotic reefs, although well described for shallow waters, remains largely unstudied. We found that representatives of many scleractinian species are brightly fluorescent at depths of 50–60 m at the Interuniversity Institute for Marine Sciences (IUI) reef in Eilat, Israel. Some of these fluorescent species have distribution maxima at mesophotic depths (40–100 m). Several individuals from these depths displayed yellow or orange-red fluorescence, the latter being essentially absent in corals from the shallowest parts of this reef. We demonstrate experimentally that in some cases the production of fluorescent pigments is independent of the exposure to light; while in others, the fluorescence signature is altered or lost when the animals are kept in darkness. Furthermore, we show that green-to-red photoconversion of fluorescent pigments mediated by short-wavelength light can occur also at depths where ultraviolet wavelengths are absent from the underwater light field. Intraspecific colour polymorphisms regarding the colour of the tissue fluorescence, common among shallow water corals, were also observed for mesophotic species. Our results suggest that fluorescent pigments in mesophotic reefs fulfil a distinct biological function and offer promising application potential for coral-reef monitoring and biomedical imaging.

Coral reef net ecosystem calcification (NEC) has decreased for many Caribbean reefs over recent decades primarily due to changes in benthic community composition. Chemistry-based approaches to calculate NEC utilize the drawdown of seawater total alkalinity (TA) combined with residence time to calculate an instantaneous measurement of NEC. Census-based approaches combine annual growth rates with benthic cover and reef structural complexity to estimate NEC occurring over annual timescales. Here, NEC was calculated for Hog Reef in Bermuda using both chemistry and census-based NEC techniques to compare the mass-balance generated by the two methods and identify the dominant biocalcifiers at Hog Reef. Our findings indicate close agreement between the annual 2011 census-based NEC 2.35 ± 1.01 kg CaCO 3 •m −2 1•y − and chemistry-based NEC 2.23 ± 1.02 kg CaCO 3 •m −2 •y −1 at Hog Reef. An additional record of Hog Reef TA data calculated from an autonomous CO 2 mooring measuring pCO 2 and modeled pH total every 3-h highlights the dynamic temporal variability in coral reef NEC. This ability for chemistry-based NEC techniques to capture higher frequency variability in coral reef NEC allows the mechanisms driving NEC variability to be explored and tested. Just four coral species, Diploria labyrinthiformis, Pseudodiploria strigosa, Millepora alcicornis, and Orbicella franksi, were identified by the census-based NEC as contributing to 94 ± 19% of the total calcium carbonate production at Hog Reef suggesting these species should be highlighted for conservation to preserve current calcium carbonate production rates at Hog Reef. As coral cover continues to decline globally, the agreement between these NEC estimates suggest that either method, but ideally both methods, may serve as a useful tool for coral reef managers and conservation scientists to monitor the maintenance of coral reef structure and ecosystem services.

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Spatial and temporal patterns of coral black band disease (BBD) prevalence were examined during the summers of 2004 to 2008 at 10 reef sites located along a sewage gradient on either side of a major marine outfall on Bermuda's south shore. The gradient was identified by current meter and drogue deployments and confirmed by a water quality monitoring using fecal indicator bacteria (gastrointestinal enterococci) as a sewage marker. BBD prevalence was also examined at 22 locations across the Bermuda platform in different physiographic reef zones, identified by reef survey techniques and analysis of community composition. BBD prevalence was generally low and was recorded in Diploria strigosa > Montastraea franksi > M. cavernosa = D. labyrinthiformis > Porites astreoides and the hydrocoral Millepora alcicornis. Most occurrences were in D. strigosa, and BBD prevalence was highest on the outer rim reef (range: 0.3 to 1.9%), followed by the outer lagoonal patch reefs (range: 0.05 to 0.8%) and the deeper terrace reefs (range: 0.1 to 0.2%). BBD prevalence levels decreased over the study period, and BBD was only rarely observed in D. labyrinthiformis, which appears to be immune to infection in Bermuda. The BBD prevalence in D. strigosa was lower on reefs regularly exposed to sewage than on the near pristine outer rim reef sites, which experience the exceptional water quality characteristics of the oligotrophic North Atlantic gyre. KEY WORDS: Coral · Black band disease · Sewage · Bermuda Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 462: 79-92, 2012 80 most widespread diseases in the Carib bean and adjacent waters (Antonius 1981, Weil 2004, primarily infecting massive framework building scleractinian corals, including Diploria spp., Montastraea spp., Colpophyllia natans and Siderastrea siderea (Antonius 1981, Edmunds 1991, Sutherland et al. 2004). The disease is now recognized as having a global distribution (Sutherland et al. 2004).A number of field studies have suggested a link between sewage pollution and BBD outbreaks. Taylor (1983) reported an association between BBD prevalence and sewage pollution or poor water quality, but the study does not show any data, and reference is made to other still unpublished work by the same author suggesting the association. Antonius (1985) purports to show a link between disease frequency and sewage pollution, but again, the evidence is based upon a perceptible increase in BBD frequency near a sewage outfall; no data are shown. Kaczmarsky et al. (2005) recorded a significantly higher prevalence of BBD and White Plague type II in corals at a single location compared to a single control site 2.5 km away. The site where the disease prevalence was higher was occasionally exposed to un-treated sewage (during emergency sewage bypass events). Kuta & Richardson (2002) found a positive relationship between elevated nitrite and BBD prevalence in Florida but did not find an overall positive correlation with the more readily assimilab...