There has been much discussion and some controversy regarding the role of nutrient enrichment versus other factors, such as altered rates of herbivory, in the degradation of coral reef ecosystems. The resolution of this controversy has been hampered by the lack of manipulative field studies testing the effects of ecologically relevant levels of nutrient enrichment on coral reef communities. We present a new method for adding ecologically relevant levels of nutrients to experimental substrates on coral reefs. The method elevates nutrients for sustained periods of time (Ͼ41 d without replenishment of nutrients) and allows for testing interactions of nutrients and altered levels of herbivory. Results from an offshore reef in Key Largo, Florida, show strong effects of excluding large herbivorous fishes, negligible effects of nutrient enrichment-or effects that are opposite of predictions, and no interaction between nutrient levels and herbivory in affecting algal abundance. Patterns observed for this reef did not confirm predictions of previously proposed models that frondose macroalgal or crustose algal abundance would be enhanced with nutrient enrichment or that dominance of filamentous turfs would be greater in unenriched conditions. In contrast to previous predictions, the abundance of larger macroalgae at this site was not increased by elevating nutrients above predicted threshold response levels of 1.0 M for total inorganic nitrogen or 0.10 M for soluble reactive phosphate. Also conflicting with some models, filamentous, nitrogen-fixing cyanobacteria were enhanced, rather than suppressed, by nutrient enrichment.There is considerable concern among scientists and conservationists regarding the degradation of coral reef com-

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Domestic wastewater disposal practices in the Florida Keys are primarily limited to on-site disposal systems such as septic tanks, injection wells, and illegal cesspits. Poorly treated sewage is thus released into the highly porous subsurface Key Largo limestone matrix. To investigate the fate and transport of sewage in the subsurface environment and the potential for contamination of marine surface waters, we employed bacteriophages as tracers in a domestic septic system and a simulated injection well in Key Largo, Florida. Transport of bacteriophage ⌽HSIC-1 from the septic tank to adjacent surface canal waters and outstanding marine waters occurred in as little as 11 and 23 h, respectively. Transport of the Salmonella phage PRD1 from the simulated injection well to a canal adjacent to the injection site occurred in 11.2 h. Estimated rates of migration of viral tracers ranged from 0.57 to 24.2 m/h, over 500-fold greater than flow rates measured previously by subsurface flow meters in similar environments. These results suggest that current on-site disposal practices can lead to contamination of the subsurface and surface marine waters in the Keys.

We surgically implanted coded-acoustic transmitters in a total of 46 coral reef fish during a saturation mission to the Aquarius Undersea Laboratory in August 2002. Aquarius is located within the Conch Reef Research Only Area, a no-take marine reserve in the northern Florida Keys National Marine Sanctuary. Over the course of 10 days, with daily bottom times of 7 hrs, saturation diving operations allowed us to collect, surgically tag, release, and subsequently track fishes entirely in situ. Fish were collected using baited traps deployed adjacent to the reef as well as nets manipulated on the bottom by divers. Surgical implantation of acoustic transmitters was conducted at a mobile surgical station that was moved to different sites across the reef. Each fish was revived from anesthetic and released as divers swam the fish about the reef. Short-term tracking of tagged fish was conducted by saturation divers, while long-term fish movement was recorded by a series of acoustic receivers deployed on the seafloor. Though not designed as an explicit comparison with surface tagging operations, the benefits of working entirely in situ were apparent.

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