
TY  - JOUR
A1  - Campbell, Stuart J. 
T1  - Uptake of ammonium by four species of macroalgae in Port Phillip Bay, Victoria, Australia
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 1999
VL  - 50
IS  - 6
SP  - 515
EP  - 522
KW  - 
UR  - https://doi.org/10.1071/MF98058 
N2  - The uptake rates of ammonium were determined for three species of native macroalgae and an exotic macroalga from Port Phillip Bay. All species exhibited rate-saturated mechanisms of uptake described by Michaelis&#8211;Menten uptake kinetics. At the highest concentration examined (28.6 &#181;mol NH4-N) Hincksia sordida had a higher rate of uptake (435 &#181;mol NH4 -N g dry wt&#8211;1 h&#8211;1) than Ulva sp. (108 &#181;mol NH4-N g dry wt&#8211;1 h&#8211;1) or Polysiphonia decipiens (53 &#181;mol NH4 -N g dry wt&#8211;1 h&#8211;1). Maximum surge uptake rate was highest for H. sordida and lowest for P. decipiens (802 and 57 &#181;mol NH4 -N g dry wt&#8211;1 h&#8211;1 respectively). The introduced phaeophyte Undaria pinnatifida had an intermediate capacity for ammonium uptake which was dependent on blade maturity. Differences in the ratio of maximum uptake rate to half-saturation rate between surge and assimilation uptake phases suggest a propensity for some species to take up ammonium at low concentrations. The relationships between nutrient uptake and growth among species would afford mature U. pinnatifida, H. sordida and Ulva sp. a competitive advantage for ammonium uptake in winter during high N availability, whereas P. decipiens would be able to exploit low N concentrations in spring and summer. 
ER  -

