|Seagrass and seaweed competition for nitrogen uptake|
Califano, G. (2011). Seagrass and seaweed competition for nitrogen uptake. MSc Thesis. University of Algarve, Centre of Marine Science: Faro. 30 pp.
Ammonium; Nitraten; Opname; Stikstof; Zeegras; Ulva Linnaeus, 1753 [WoRMS]; Zostera subg. Zosterella noltei Hornemann [WoRMS]; Zostera subg. Zosterella noltei Hornemann [WoRMS]; Marien
seagrass; seaweed; ammonium uptake; nitrate uptake; Zostera noltii; Ulva spp.; nitrogen competition.
The constant risk of overgrowth of macroalgae, the reduction of seagrasses meadows and their effects on the trophic chain and on the whole ecosystem (human kind included), were the starting point for more studies exploring the relations existing between seagrasses and ephemeral macroalgae. A wide literature review showed a huge difference between nitrogen uptake ability of seaweed and seagrass. However the predominance of seagrass in several pristine environments doubts the accuracy of the literature results at low nutrient concentration in the water column. Then an experimental approach to test the ecological competition for inorganic nitrogen between two different species is performed in the present work. One ephemeral macroalgae, Ulva spp., and one slow growing seagrass species, Zostera noltii, incubated in the same media at constant inorganic nitrogen saturation at different concentration for one hour showed peculiar outcomes. At low concentration of nitrate in the water column, seagrasses could outcompete with seaweed due to the advantage to uptake nutrients from the roots. Higher performances of Zostera noltii than Ulva spp. in the uptake of ammonium defines a complete opposite behaviour from what could be inferred from individual studies already present in the literature. Thus, further studies may focus on the eventual influence of a species on the other through the imitation of shallow water ecosystem.