Limited toxicity of NHx pulses on an early and late successional tropical seagrass species: Interactions with pH and light level

Our results indicate that the early successional H. uninervis has higher tolerance to high NHx loads as compared to the late successional T. hemprichii. H. uninervis was better able to avoid toxic internal NHx levels by further assimilating glutamine into asparagine in contrast to T. hemprichii. Moreover, both tropical species seem to cope much better with high NHx than the temperate Z. marina. The implications for the distribution and succession of seagrass species under high nutrient loads are discussed.