TY - JOUR
T1 - Phosphorus dynamics and limitation of fast- and slow-growing temperate seaweeds in Oslofjord, Norway
AU - Pedersen, Morten Foldager
AU - Borum, Jens
AU - Fotel, Frank Leck
N1 - KEY WORDS: Macroalgae · Seaweeds · Nutrient dynamics · Phosphorus · Eutrophication
PY - 2010
Y1 - 2010
N2 - During coastal eutrophication, fast-growing, ephemeral macroalgae bloom at the expense of slow-growing, perennial macroalgae. This change in community composition has been explained by a differential ability to exploit and utilize inorganic nitrogen among macroalgae with different growth strategies. However, some coastal areas are becoming phosphorus- rather than nitrogen-limited; we therefore compared phosphorus dynamics among 6 temperate species of macroalgae with different growth rates in order to test whether differences in algal P-dynamics may explain macroalgal community changes. Thin, fast-growing algae (Ulva and Ceramium) took up dissolved inorganic P (DIP) much faster than thicker, slower growing species (belonging to Fucus, Ascophyllum and Laminaria) but also had much higher P-demands per unit biomass and time. DIP concentrations in the Oslofjord were low from April through August, and fast-growing species were unable to meet their P-demand from uptake for several months during summer. Hence, Ceramium and Ulva were potentially P-limited during summer, whereas Ascophyllum and Laminaria were able to acquire sufficient external DIP to remain P-replete throughout the year. Storage of P prevented Fucus species from suffering severe P-limitation for several weeks in summer. The absolute amount of P stored within the algae per unit biomass did not differ systematically among the 6 species, but the storage capacity (i.e. the period of time for which stored P could support growth) was much larger for slower growing species since this parameter depended heavily on realized growth rate. Our results show how differences in macroalgal P-dynamics may explain the changing balance among macroalgae with different growth strategies in P-deficient coastal areas.
AB - During coastal eutrophication, fast-growing, ephemeral macroalgae bloom at the expense of slow-growing, perennial macroalgae. This change in community composition has been explained by a differential ability to exploit and utilize inorganic nitrogen among macroalgae with different growth strategies. However, some coastal areas are becoming phosphorus- rather than nitrogen-limited; we therefore compared phosphorus dynamics among 6 temperate species of macroalgae with different growth rates in order to test whether differences in algal P-dynamics may explain macroalgal community changes. Thin, fast-growing algae (Ulva and Ceramium) took up dissolved inorganic P (DIP) much faster than thicker, slower growing species (belonging to Fucus, Ascophyllum and Laminaria) but also had much higher P-demands per unit biomass and time. DIP concentrations in the Oslofjord were low from April through August, and fast-growing species were unable to meet their P-demand from uptake for several months during summer. Hence, Ceramium and Ulva were potentially P-limited during summer, whereas Ascophyllum and Laminaria were able to acquire sufficient external DIP to remain P-replete throughout the year. Storage of P prevented Fucus species from suffering severe P-limitation for several weeks in summer. The absolute amount of P stored within the algae per unit biomass did not differ systematically among the 6 species, but the storage capacity (i.e. the period of time for which stored P could support growth) was much larger for slower growing species since this parameter depended heavily on realized growth rate. Our results show how differences in macroalgal P-dynamics may explain the changing balance among macroalgae with different growth strategies in P-deficient coastal areas.
U2 - 10.3354/meps08350
DO - 10.3354/meps08350
M3 - Journal article
SN - 0171-8630
VL - 399
SP - 103
EP - 115
JO - Marine Ecology - Progress Series
JF - Marine Ecology - Progress Series
ER -
