Evaluation of Nutrient Limitation of CO Sub(2) and N Sub(2) Fixation in Marine Microbial Mats
Paerl HW, Joye SB, Fitzpatrick M. 1993. Evaluation of Nutrient Limitation of CO Sub(2) and N Sub(2) Fixation in Marine Microbial Mats. Marine Ecology Progress Series. 101(3):297-306
Photosynthetic CO sub(2) fixation and N sub(2) fixation are fundamentally important in mediating production dynamics of intertidal and subtidal marine microbial mat communities. We examined nutrient [N, P, Fe, Mo, dissolved organic carbon (DOC)] limitation of CO sub(2) and N sub(2) fixation in geographically and physiologically diverse mats. Nitrogen enrichment (as NO sub(3) super(-)) infrequently stimulated CO sub(2) fixation. Phosphorus, Fe and Mo enrichment generally failed to stimulate CO sub(2) fixation. The frequent absence of N limitation appears linked to the ability of mat microbial communities to fix N sub(2) and effectively recycle fixed N. Nitrogen fixation was enhanced by DOC, while no P, Fe or trace element stimulation was observed. The lack of nutrient stimulation of CO sub(2) fixation appeared related to low net growth rates of some mats. Slow growing mats, including hypersaline, stromatolitic (Storrs Lake, Bahamas) and certain hypersaline, lagoonal mats (Guerrero Negro, Baja California, Mexico) exhibited virtually no nutrient stimulation of either CO sub(2) or N2 fixation. More productive coastal (North Carolina, USA) and estuarine (Tomales Bay, California, USA) mats showed higher frequencies of nutrient limitation of either process. Seasonally, N and DOC stimulation were most profound during periods of maximum growth. Mats are able to minimize C and N limitation by metabolically coupling CO sub(2) and N sub(2) fixation as sources of 'new' C and N inputs respectively. Phototrophic-heterotrophic microbial consortia appear to mediate coupling, which minimizes losses of fixed C and N to overlying waters.
- Type
- Journal Article
- Authors
- Paerl, H; Joye, S; Fitzpatrick, M
- Units
- PORE
- Keywords
- algal mats, benthic environment, Benthos, biological production, Carbon fixation, community studies, Ecosystems, Energetics, Environmental Regime Marine, ER, intertidal environment, Iron, limiting factors, Microorganisms, molybdenium, Nitrogen Fixation, nutrient deficiency, Phosphorus