Patterns of dark respiration in aquatic systems


Mantikci M., Staehr P. A. , Hansen J. L. S. , Markager S.

MARINE AND FRESHWATER RESEARCH, vol.71, no.4, pp.432-442, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 71 Issue: 4
  • Publication Date: 2020
  • Doi Number: 10.1071/mf18221
  • Title of Journal : MARINE AND FRESHWATER RESEARCH
  • Page Numbers: pp.432-442
  • Keywords: bacteria, coastal ecosystems, lake, optode, phytoplankton, PLANKTON COMMUNITY RESPIRATION, DISSOLVED ORGANIC-MATTER, TEMPERATURE SENSITIVITY, BACTERIAL RESPIRATION, METABOLISM, LIGHT, GROWTH, BACTERIOPLANKTON, PHOTOSYNTHESIS, VARIABILITY

Abstract

We used continuous measurements of dissolved oxygen (DO) in dark bottles to characterise patterns of the dark respiration rate (R-dark) for three marine phytoplankton monocultures and in natural-water samples from two marine coastal systems. Furthermore, patterns of ecosystem community respiration rate were determined from open-water changes in DO in a fjord and in a lake. We considered two models of R-dark to describe temporal changes in DO: constant R-dark and decreasing R-dark; increasing R-dark. In addition, the effect of incubation time on R-dark was investigated in bottle incubations. Constant R-dark was observed in short-term (12-h) bottle incubations in natural-water samples from two marine coastal systems. Declining R-dark was observed in marine phytoplankton cultures and open-water measurements in a lake. Increasing R-dark was observed in open-water measurements in a fjord, particularly during summer. Long-term (120-h) bottle incubations in natural-water samples showed an increase in R-dark after 48 and 72 h. We show that the conventional expectation of constant rates of respiration in darkness is far from typical, because non-linear changes are common under both controlled experimental conditions, as well as for open-water measurements of ecosystem respiration.