Nutrient limitation of Enhalus acoroides, Thalassja hemprichii and Cymodocea rotundata
in 2 mixed seagrass beds (Sllaqui and Lucero) in Cape Bolinao, NW Philippines was investigated
through a 4 mo in situ nutrient addition experiment. Leaf growth of T hernprichii and E. acoroides significantly
increased by 40 to 100% and 160%, respectively, following fertilization. Leaf biomass of the
3 species also increased significantly by 60 to 240':; following nutrient additions. The increased growth
and biomass with fertilization was supported by enhanced photosynthetic activity, consequently by
higher chlorophyll and nutrient concentrations in the photosynthetic tissues. These results demonstrated
nutnent limitation of seagrass growth and photosynthetic performance at the 2 sites in Cape
Bolinao. The nature and extent of nutrient limitation, however, varied between sites and among species.
T hemprichii and E. acoroides appeared to be mainly P deficient and N deficient, respectively
(from significant increases in tissue P and iV concentration following fertilization, respectively). The
deficiency was moderate (26 % of requirement) for T hemprichii but substantial for E. acoroides (54 %
of requirement). Moreover, N and P deficiency was greater in Lucero than in Silaqui, consistent with
the higher ambient nutrient concentration in the porewater and sediment nutrient and organic matter
content in Silaqui. These results emphasize the importance of local differences in the factors controlling
nutrient losses and gains in seagrass meadows and, more importantly, the importance of identifying the
species-specific traits that generate the interspecific plasticity of nutrient status.