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Abstract: Bioerosion by Cliona delitrix and Cliona lampa was assessed at 43 sites along the Florida Reef Tract, USA, in the summer of 2001. Sponge abundances were estimated using rapid visual assessment. Tissue samples of sponges were taken for analysis of δ 15N. Comparison samples were taken from Belize. Annual trends in sponge abundance were estimated from archived videos covering the period from 1996 to 2001. Sites with the greatest boring sponge size and cover were in the Backcountry and Lower Keys, where total nitrogen, ammonium, and δ 15N levels were highest. The sites with the largest relative increase of C. delitrix and C. lampa over the 5 year period were in the Upper Keys, where the greatest relative decline in stony coral cover has occurred. Florida sponge δ 15N values were 5.2(±0.1)%, suggesting the influence of human waste; in comparison, offshore Belize samples were 2.1(±0.1)%. These results suggest sewage contamination of the Florida Reef Tract, shifting the carbonate balance from construction to destruction. [Copyright &y& Elsevier]

Species-area curves calculated from line-intercept transect surveys on 15 reefs in three regions of Indonesia allow estimation of the relative decrease in within-habitat coral species diversity associated with different types of reef degradation. Reefs subject to land-based pollution (sewage, sedimentation, and/or industrial pollution) show 30-50% reduced diversity at 3 m, and 40-60% reduced diversity at 10 m depth relative to unpolluted comparison reefs in each region. Bombed or anchor damaged reefs are ca 50% less diverse in shallow water (3 mdepth) than are undamaged reefs in the same region, but at 10 m depth the relative decrease is only 10%. Comparison reefs in the Java Seaare ca 20% less diverse than their counterparts in Ambon, Maluku. The results, compared with a previous survey in the Spermonde Archipelago found a 25% decrease in generic diversity of corals on two reefs resampled after 15 years. The decreased diversity on reefs subject to land-based pollution implies a dramatic, rapid decrease in Indonesianreef-based fisheries resources. [ABSTRACT FROM AUTHOR]