Preliminary evaluation of the use of phosphogypsum for reef substrate. II. A study of the effects of phosphogypsum exposure on diversity and biomass of acquatic organisms

The effects of cement consolidateti phosphogvpsum (PG) ori marine organisms was investigateti under natural conditions in four 1000 M2 estuarine ponds. Two ponds were seeded with 160 kg of PG arranged in agl-re-gations of blocks and two ponds received similar mass of santi/cement blocks. Meiofauna were sampled quarterly and PG diti not affect total meiofauna or major taxa (nematodes and copepods) density. Abundant species of copepods either were slightly increased in ponds with PG or were inconsistently affected.A11 ponds were drained after one year. Three species of macroinvertebrates and 15 species of fishes were colleeted. Diversity indices showed modest but inconsistent variation among ponds. Only Pond 1 (contro!) and Pond 4 (experimental) had similar species abundances and all ponds showed unique distributions of biomasses among species. Thus, no differences in community structure attributable to tbc presenee of PG could be detected amorig benthie invertebrates, natant invertebrates, or fishes.