|Fluxes of bacterioplankton between a tidal estuary and the sea: returning to the “Outwelling Hypothesis”|
Cunha, M.A.; Dias, J.M.; Almeida, M.A.; Lopes, J.F.; Alcântara, F. (2003). Fluxes of bacterioplankton between a tidal estuary and the sea: returning to the “Outwelling Hypothesis”. Aquat. Ecol. 37(1): 45-54
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588, more
Estuaries; Nannoplankton; Tidal dynamics; ANE, Portugal, Ria de Aveiro [Marine Regions]; Marine
|Authors|| || Top |
- Cunha, M.A., correspondent
- Dias, J.M.
- Almeida, M.A.
- Lopes, J.F.
- Alcântara, F.
The tidal dynamics of bacterioplankton communities at the outer part of a shallow estuary (Ria de Aveiro, Portugal) were studied during 6 tidal cycles at a fixed sampling site. Bacterial numbers (0.2-8.1 × 109 cells l-1), aminopeptidase activity (189-1662 nmol l-1 h-1), β-glucosidase activity (1.7-67.0 nmol l-1 h-1) and potential glucose incorporation (0.48-3.99 nmol l-1 h-1) followed a consistent pattern of increase during ebb and decrease during flood. Fluxes of bacterioplankton populations and associated heterotrophic activities between the estuary and the coastal area during a tidal cycle were estimated from the water flux as derived from a two-dimensional vertically-integrated numerical model. The net fluxes estimated for a tidal cycle ranged from -26.0 to -2.5 to × 1016 bacterial cells. The net tidal fluxes of potential heterotrophic activities ranged from -10 to -80 mol h-1 for aminopeptidase, -0.33 to -1.10 mol h-1 for β-glucosidase and -0.18 to +0.03 mol h-1 for glucose incorporation. Net fluxes were generally negative in sign indicating the transfer of phyto- and bacterioplankton, as well as potential capacities for the degradation and recycling of organic matter, from the outer estuarine compartment to the sea.