Dissolved organic carbon in a humic lake: effects on bacterial production and respiration

Hydrobiologia ◽  
1992 ◽  
Vol 229 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Dag O. Hessen
2000 ◽  
Vol 45 (3) ◽  
pp. 664-676 ◽  
Author(s):  
Anssi V. V äh ätalo ◽  
Mirja Salkinoja -Salonen ◽  
Petteri Taalas ◽  
Kalevi Salonen

2005 ◽  
Vol 75 (3) ◽  
pp. 393-407 ◽  
Author(s):  
Kelly O. Maloney ◽  
Donald P. Morris ◽  
Carl O. Moses ◽  
Christopher L. Osburn

2005 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Todd Tietjen ◽  
Anssi V. Vähätalo ◽  
Robert G. Wetzel

2015 ◽  
Vol 12 (11) ◽  
pp. 8199-8234
Author(s):  
V. Kasurinen ◽  
H. Aarnos ◽  
A. Vähätalo

Abstract. In order to assess the production of biologically labile photoproducts (BLPs) from non-labile riverine dissolved organic carbon (DOC), we collected water samples from ten major rivers, removed labile DOC and mixed the residual non-labile DOC with artificial seawater for microbial and photochemical experiments. Bacteria grew on non-labile DOC with a growth efficiency of 11.5% (mean; range from 3.6 to 15.3%). Simulated solar radiation transformed a part of non-labile DOC into BLPs, which stimulated bacterial respiration and production, but did not change bacterial growth efficiency (BGE) compared to the non-irradiated dark controls. In the irradiated water samples, the amount of BLPs stimulating bacterial production depended on the photochemical bleaching of chromophoric dissolved organic matter (CDOM). The apparent quantum yields for BLPs supporting bacterial production ranged from 9.5 to 76 (mean 39) (μmol C mol photons−1) at 330 nm. The corresponding values for BLPs supporting bacterial respiration ranged from 57 to 1204 (mean 320) (μmol C mol photons−1). According to the calculations based on spectral apparent quantum yields and local solar radiation, the annual production of BLPs ranged from 21 (St. Lawrence) to 584 (Yangtze) mmol C m−2 yr−1 in the plumes of the examined rivers. Complete photobleaching of riverine CDOM in the coastal ocean was estimated to produce 10.7 Mt C BLPs yr−1 from the rivers examined in this study and globally 38 Mt yr−1 (15% of riverine DOC flux from all rivers), which support 4.1 Mt yr−1 of bacterial production and 33.9 Mt yr−1 bacterial respiration.


2000 ◽  
Vol 57 (2) ◽  
pp. 487-496 ◽  
Author(s):  
Michael L Pace ◽  
Jonathan J Cole

We assessed planktonic respiration in whole-lake manipulations of nutrient loading and food web structure in three manipulated and one unmanipulated lake over 7 years. The manipulations created strong contrasts in zooplankton body size across a series of nutrient loads. Large-bodied zooplankton were suppressed by planktivorous fish in one lake, while in the other two manipulated lakes, large-bodied zooplankton dominated community biomass. Nutrients were added as inorganic N and P. Nutrient loads ranged from background to conditions resembling eutrophic lakes. Planktonic respiration was measured weekly in each lake by dark bottle oxygen consumption. Respiration was low when lakes were not fertilized (average 8.5 µmol O2·L-1·day-1) and was correlated with differences in dissolved organic carbon among the lakes. Respiration increased with nutrient addition to a mean range of 12-25 µmol O2·L-1·day-1; however, respiration differed among lakes at the same nutrient loading. Further, respiration was independent of dissolved organic carbon in the fertilized lakes. Differences in the intensity of zooplankton grazing as determined by food web structure strongly regulated primary and bacterial production across the range of nutrient loads. Consequently, respiration was positively related to primary production, phytoplankton biomass, and bacterial production and inversely related to the average size of crustacean zooplankton.


Sign in / Sign up

Export Citation Format

Share Document