Biomass, production, and specific growth rate of bacterioplankton and coupling to phytoplankton in an oligotrophic lake

Abstract

Production of bacterioplanktonand phytoplankton was analyzed in oligotrophic Lawrence Lake, Michigan, over a 2-yr period. Variables examined were temperature, bacterial numbers and biovolumes, bacterial production and specific growth rates (p), phytoplanktonic biomass and production, and alkaline phosphatase activity. Algal and bacterial production varied similarly on temporal and spatial scales; some differences in vertical patterns were evident during summer stratification. Values for p ranged from 0.2 d-l during winter to 2.6 d-l in midsummer. Decreases in specific growth rates of bacteria coincided with the onset of heavy CaCO, precipitation and with increased alkaline phosphatase activities. p was close to predicted maximal values during periods of mixing but was depressed in upper layers during summer. Temperature showed significant bivariate rank correlations with all variables. With temperature controlled, p did not show significant partial correlations with algal chlorophyll or production, consistent with a minor role of dissolved organic carbon from phytoplankton for bacterial growth. Low and high estimates of bacterioplanktonic production over 2 yr exceeded that of phytoplankton by factors of 1.33 and 3.35. Net metabolism in the pelagic zone was heterotrophic, a state likely maintained by littoral macrophytic and periphytic production. Apparent coupling between phyto-and bacterioplankton stemmed mainly from similar responses of each component to common regulating factors rather than from direct metabolic links.Abundance and production of bacterioplankton and phytoplankton have been demonstrated to covary across a large range of trophic states in both freshwater and marine ecosystems (e.g. Bird and Kalff 1984;Cole et al. 1988). These relationships have supported a general conceptual model of bacterial dependence, either direct or indirect, on algal production as a primary source of organic substrates, although alternative interpretations have been offered (Cole et al. 1988;Currie 1990). Further, these Acknowledgments This research was supported by the National Science Foundation(BSR 83-07716,BSR 8%17039,andOSR91-08761)and the Department of Energy (DE-FG02-87ER605 15). We acknowledge the technical assistance of J. Sonnad, S. Marsh Ford, and N. L. Consolatti in the laboratory and the many colleagues that assisted with field measurements. We appreciate the critical review of E. Roden and the comments of two anonymous reviewers.

The Effects of System-Level Nutrient Enrichment on Bacterioplankton Production in a Tidally-Influenced Estuary**

“…However, covariation of BP and CHLA may also occur if both bacterioplankton metabolism and phytoplankton biomass are simultaneously yet independently regulated by an external factor, such as inorganic nutrient availability (e.g., COVENEY and WETZEL, 1995;SMITH and KEMP, 2003;VREDE et al, 1999). Under such circumstances, nutrients subsidize algal production while bacterioplankton combine nutrients with allochthonous (i.e., nonalgal) sources of organic matter to fuel growth, evidence of which was observed in the studies discussed earlier (i.e., REVILLA et al, 2000).…”

Relaciones entre las abundancias del bacterioplancton y del fitoplancton en tres ecosistemas lénticos de los Andes Colombianos

“…En diversos ecosistemas acuáticos se ha encontrado un acoplamiento entre microalgas y bacterias, en el cual la liberación de carbono orgánico disuelto (COD) por parte del fitoplancton controla parcialmente el crecimiento del bacterioplancton; éste a su vez libera nutrientes utilizables por las microalgas, lo que favorece su desarrollo (Currie 1990, Cole et al 1993, Coveney and Wetzel 1995, del Giorgio et al 1997, Havens et al 2000. Dicha relación depende de factores que afectan a las dos comunidades, como temperatura y disponibilidad de fósforo, e influye sobre su productividad, abundancia y composición.…”

Effects of nutrients (phosphorous, nitrogen, and carbon) and zooplankton on bacterioplankton and phytoplankton—a seasonal study

“…Additions of inorganic nutrients have been reported to stimulate bacterioplankton growth directly in several studies (Toolan et al 1991;Coveney and Wetzel 1992;Le et al 1994), but indirect stimulation via increased phytoplankton growth and increased release rates of organic C from phytoplankton has also been found (Riemann and Søndergaard 1986;Wang et al 1992). Taken together, these findings indicate that the correlation between bacterioplankton and phytoplankton growth can be attributed either to bacterial dependence on organic C released from phytoplankton or to the regulation of both bacterioplankton and phytoplankton growth by the same factor.…”

“…These correlations can be ascribed to the dependence of bacteria on organic carbon (C) derived from phytoplankton. However, the correlations may also reflect an indirect relationship mediated via dependence on common regulating factors such as temperature and nutrients (Currie 1990;Coveney and Wetzel 1995).…”