Coral cover remains highest on patch reefs at the northern end of the Florida reef tract. The reasons for this trend are not well understood, but may be related to the protection from extreme variations in water quality parameters provided by the near constant presence of islands at the north extent of the Florida Keys. Three indices have been developed based on Foraminifera and sediment constituents. Two of the indices, the FORAM Index and the SEDCON Index, were developed to indicate the suitability of a reef environment for continued reef accretion. The third index, the Photic Index, is an assessment of photic stress on reefs based on incidence of bleaching in a species of Foraminifera, Amphistegina gibbosa, which is known to experience loss of algal endosymbionts similar to bleaching in corals. Patch reefs were sampled in Biscayne National Park, FL to assess sediment characteristics and foraminiferal assemblages, as well as to examine trends in the three indices. Sediments associated with a majority (59%) of reefs were coarse sands; muddy sediments were restricted to a few inner patch reefs that were isolated from the influence of Caesar's Creek, which flushes water from inside Biscayne Bay onto the open shelf. Unidentifiable grains predominated in the sediment constituents, along with calcareous algae and molluskan debris. Shells from 82 genera of Foraminifera were identified in the sediments. Quinqueloculina was the most consistently common genus. Percent mud was the single most influential measured variable on the distribution of both sediment constituents and foraminiferal assemblages. Analysis of bleaching in the foraminifer Amphistegina gibbosa revealed that photo-oxidative stress was chronic at 94% of the sites. Patterns of FORAM and SEDCON Index values and their similarity to temperature, salinity, and percent mud distributions show that Caesar's Creek is affecting the benthic community in its immediate vicinity by providing flow that limits the accumulation of mud and potentially other anthropogenic stressors. Overall this study suggests that the reefs in this area are marginal for continued reef growth. A more detailed study of water quality through Caesar's Creek should be conducted to determine exactly how it is affecting the reefs in Biscayne National Park.

A goal of the U.S. Environmental Protection Agency is to develop protocols applicable to coral reefs to distinguish between the effects of local water quality and those associated with regional to global environmental change. One test case is the current-dominated southeast coast of Florida where the Delray Outfall delivers 30 million gallons per day (114,000 cubic meters per day) of secondary-treated sewage into the ocean. Five study sites were established at depths between 15 and 18 m, and at distances between 1 and 18 km distance from the outfall, where the Stony Coral Rapid Bioassessment Protocol (RBP) was conducted to determine coral cover and selected other parameters. During sampling, 29 surface sediment samples were collected that I analyzed with respect to sediment texture, foraminiferal assemblages, and sediment constituents. Most samples were characterized by fine sands with <2% mud. A total of 77 genera of foraminifers were identified, averaging 28 genera per sample. Abundances of foraminiferal shells varied among samples by more than an order of magnitude (83 to 1010 shells per g sediment). The Foraminifera in Reef Assessment and Monitoring (FORAM) Index was calculated from the foraminiferal data, yielding values of 3 or more for all sites, with 26 of the 29 test sites yielding values >4, indicating that water quality should support coral growth. Sediment constituent analyses revealed that the sediments were overwhelmingly dominated by unidentifiable fragments (60%), with molluscan debris second (20%), and calcareous algae third (4.5%); larger foraminiferal shells and coral fragments together made up < 5.5%. The resulting sediment constituent (SEDCON) Index was consistently <2, indicating that erosional processes dominate over sediment production along the sampled shelf area. Results provided by the FORAM and SEDCON indices are consistent with results for stony coral based on the RBP. Stony coral cover was low at all sites, <2%, indicating that coral occurs in the area but neither dominates the benthos nor builds reefs. No relationship was observed between any parameter and distance from the Delray Outfall. However, both the RBP and FORAM Index indicated poorest conditions at the Horseshoe site, suggesting unidentified stressors in that vicinity.

Resource managers need inexpensive bioindicators to evaluate the health of coral reef ecosystems and to inform decisions on when and where to utilize more expensive assessment techniques. Following USEPA Guidelines for Evaluating Ecological Indicators, I developed the SEDCON Index (SI), a rapid-assessment protocol whichutilizes reef sediment composition to assess the integrity of coral-reef communities. Keyadvantages of this index are that it entails non-destructive sampling and is applicable to reefs worldwide. The underlying assumption of the index is that community structure is reflected by proportions of recognizable remnants of calcareous shells and skeletal remains of mixotrophic (zooxanthellate corals and larger foraminifers), autotrophic (calcareous and coralline algae), and heterotrophic (e.g., bryozoans, molluscs, smaller foraminifers) benthic organisms, as well as unrecognizable debris as a proxy for bioerosion.

From the Proceedings of the 1982 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona - Nevada Academy of Science - April 24,1982, Tempe, Arizona / A prototypical computer simulation model has been developed to aid watershed managers in estimating impacts of alternative land management practices on nutrient and heavy metal losses due to transported sediment on forested watersheds of the southwestern United States. The model, called SEDCON, allows users at remote locations with modest computer terminal equipment and commonly available data to obtain reliable estimates of nutrient and heavy metal concentrations in suspended sediment originating on uniformly-stocked, forested watersheds in the Southwest. SEDCON has been structured in an interactive mode to facilitate its use by persons not familiar with computer operations. Written in FORTRAN IV computer language, the model requires approximately 5000 words of core. SEDCON is operative on a DEC-10 computer at the University of Arizona.