Nutrient control of algal growth in estuarine waters. Nutrient limitation and the importance of nitrogen requirements and nitrogen storage among phytoplankton and species of macroalgae
Year: 1996
Type: article
Abstract: Nutrient enrichment of shallow coastal waters changes the composition of plant communities so that slow-growing, benthic macrophytes are replaced by fast-growing algae such as phytoplankton and ephemeral macroalgae.This scenario suggests that fast-growing algae suffer more from nutrient limitation than slow-growing algae at low nutrient availability.We tested this hypothesis by comparing the effect of in situ nutrient enrichment on the phytoplankton community, 4 ephemeral macroalgae (Ulva lactuca, Cladophora serica, Chaetomorpha linum and Ceramiurn rubrum) and 1 perennial macroalga (Fucus vesiculosus).Nitrogen was the main limiting nutrient to algal growth and fast-growing algae were N limited for a longer period during summer than slower-growing species.Differences in the temporal extent of N limitation were related to species-specific variations in N requirements for growth and in N storage pools.The N requirements per unit biomass and time were up to 30-fold higher for fast-growing algae compared to slow-growing species due to 10-fold faster growth and 3-fold higher demands for the internal N concentration needed to sustain maximum growth (i.e.critical concentrations).The pools of N reserves only varied 2-fold among algal species and could support maximum growth for 0.5 d in the phytoplankton community and for 12 d in E vesiculosus.Growth of phytoplankton and E vesiculosus could proceed at reduced rates for another 2.6 and 34 d.respectively, based on other internal pools of N. The results suggest that the species-specific differences in growth rate and critical N concentrations account for a substantial part of the variation in the duration of nutrient limitation among different algal types and, therefore, provide further clarification of the reasons why fast-growing algae are stimulated by increased nutrient availability while slowgrowing algae remain unaffected or are hampered due to shading.
Source: Marine Ecology Progress Series
DOI: 10.3354/meps142261
Authors: MF Pedersen, J Borum
Institutions: Roskilde University, University of Copenhagen
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: bronze
OpenAlex ID: W2045410088