ISSN:
1573-5117
Keywords:
bioassay
;
Chlorophyta
;
functional-form
;
Halimeda
;
nutrients
;
productivity
;
seaweed
;
Udotea
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Members of the green algal order Bryopsidales (= Caulerpales) are important calcifying agents of tropical reefs and comprise two fundamentally different life-form groups: (1) epilithic species with limited attachment structures and (2) psammophytic forms that have extensive subterranean rhizoidal systems. Because the shallow-water habitats of the former have relatively low nitrogen (N) to phosphorus (Pi) ratios compared to the pore waters of the sedimentary carbonate-rich substrata in which the latter are anchored, we hypothesized that epilithic forms should tend to be relatively more limited by N, while psammophytic species should tend to show Pi limitation. In partial support of the hypothesis, light-saturated net photosynthesis (Pmax) in the epilithic forms, Halimeda opuntia, H. lacrimosa and H. copiosa, tended to be enhanced by N, while Pi was inhibitory or had no effect. In contrast, the psammophytic forms, Udotea sp., U. conglutinata, H. monde, H. tuna and H. simulans, tended to be stimulated more by Pi, whereas N had little effect. The utility of a bioassay to assess macroalgal nutrient limitation, based on a physiological response (net Pmax) to short-term nutrient pulses, is demonstrated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00040214
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