Monterey Bay Aquarium Research Institute
Marine Botany

Ulva title imageEcology  

Distribution    Biotic Interactions    Nutrients    Bioindicators    


The distribution of Ulva species can be limited by nitrogen concentrations.  Due to their high nitrogen requirements, reduced ability to take up nitrogen, and limited ability to store it, Ulva need to be in nitrogen-rich environments. On the other hand, when nitrogen is available in particularly high concentrations, Ulva are able to take up more than most species and use it to grow rapidly.  This feature of Ulva makes it very successful in nitrogen-rich areas due to sewage pollution. Nutrient availability is known to influence reproduction in the microalgal species U. fasciata. Specifically, less nitrogen concentrations lead to enhanced gamete formation, while high nitrogen concentrations lead to vegetative growth and asexual reproduction. Nitrogen deficiency is known to suppress reproduction in many species, for example U. lactuca, in which high concentrations of ammonium have been seen to cause abundant zoospore formation.

As I said before, Ulva are found in abundance in areas with enhanced nutrient supplies, including anthropogenically altered areas where sewage is released into the water. Nuisance growths of Ulva can occur in such areas, especially if they are enclosed or semi-enclosed and experience little mixing. In these areas, Ulva comprise a large proportion of drift plants, which can smother the benthic communities below.  

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