Patterns of Seagrass and Sediment Nutrient Distribution Suggest Anthropogenic Enrichment in Laamu Atoll, Republic of Maldives

Abstract

Sampling of seagrass cover and sediment nutrients was undertaken in lagoonal habitats of Laamu Atoll (Republic of Maldives) adjacent to three traditional fishing villages (fishing the predominant economic activity for more than 30 yr), three other villages (not traditional landing sites), and four uninhabited islands to determine if chronic input of organic fishing waste from the traditional fishing villages could explain spatial distribution of seagrass cover. Results indicated significantly greater cover of seagrass at the traditional fishing village sites than the other two site groups. Analysis of dried sediments showed sediments at traditional fishing village sites were significantly enriched with phosphorus, though no significant difference in nitrogen was found between groups of sites. These results, together with studies showing that sediment nutrient pools can limit seagrass bed development, suggest that anthropogenic enrichment of lagoonal sediments by fishing waste over generational time scales may have caused substantial proliferation of seagrass beds.