Nutrient limitation of the tropical seagrass Enhalus acoroides (L.) Royle in Cape Bolinao, NW Philippines

Experimental additions of nutrients to the sediment of Enhalus acoroides stands were performed at four sites and three times along the year in Cape Bolinao, NW Philippines to test the hypothesis that seagrass growth in tropical environments is limited by the availability of nutrients. Both the nitrogen content (as % DW) and the nitrogen incorporation of E. acoroides leaves increased after the addition of nutrients. The size (g DW per shoot) and the leaf growth rates (g DW per shoot d^-1) of E. acoroides shoots also increased after the addition of nutrients. Nitrogen rather than phosphorus was the nutrient limiting shoot size and leaf growth of E. acoroides in the area. The extent of nutrient limitation of E. acoroides showed high variability both in space and time which cannot be directly linked with differences in light or nutrient availability among the experimental sites.