Abstract
Understanding the connections between biological communities and elemental cycles is increasingly important given that alterations to both are occurring on a global scale. Biological control of elemental cycles is tied to patterns of biomass and the elemental stoichiometry of organisms and organic matter (OM) pools that comprise ecosystems. The structure and size of these ecosystem components are, in turn, shaped by key environmental factors that influence species composition, functional traits, and OM and element storage. In stream and river ecosystems, temperature and flow regime have a strong influence on ecosystem structure and function, yet little is known about their relative importance in driving patterns of ecosystem OM and stoichiometry. We quantified ecosystem OM pools and elemental stoichiometry in 11 Icelandic streams across a wide gradient of temperature (~ 5 to 25 °C) and flow. Across these environmental gradients, we observed two orders of magnitude variation in ecosystem OM mass, as well as relatively large variation in certain ecosystem stoichiometries (that is, C:N, C:P). We found that flow regime was more important than temperature in driving variation in OM pools and stoichiometry because of large shifts in community structure, that is, from dominance by large-bodied macrophyte and bryophyte communities to epilithic and detrital OM pools. Although temperature is known to influence mass-specific rates of metabolic and chemical processes, our study suggests that the flow disturbance regime may be the dominant control on patterns of OM storage and may thus control ecosystem fluxes by constraining ecosystem OM pool mass, organism size structure, and stoichiometric traits.
| Original language | English |
|---|---|
| Pages (from-to) | 1317-1331 |
| Number of pages | 15 |
| Journal | Ecosystems |
| Volume | 24 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Sept 2021 |
Bibliographical note
Funding Information: We would like to thank a number of individuals who contributed to this work: A. Toomey, B. Weigel, S. Layton, and R. McClure provided indispensable help in the field and laboratory. E. J. N. Brookshire, G. C. Poole and B. O. L. Demars contributed input on earlier versions and two anonymous reviewers provided feedback that greatly improved the clarity of the manuscript. We are grateful to Sigurður Guðjonsson, Guðni Guðbergsson, and the staff at the Veiðimálastofnun for laboratory space and logistical support. We are also grateful to Sveinbjörn Steinórsson of the University of Iceland for winter transport to our field sites. This work was supported in part by a Grant-In-Aid-of-Research to JRJ from Sigma-Xi (Grant ID #G20120315162084) and from the National Science Foundation (DEB-0949726 to WFC and DEB-0949774 and DEB-1354624 to JPB and ADH). Funding Information: We would like to thank a number of individuals who contributed to this work: A. Toomey, B. Weigel, S. Layton, and R. McClure provided indispensable help in the field and laboratory. E. J. N. Brookshire, G. C. Poole and B. O. L. Demars contributed input on earlier versions and two anonymous reviewers provided feedback that greatly improved the clarity of the manuscript. We are grateful to Sigur?ur Gu?jonsson, Gu?ni Gu?bergsson, and the staff at the Vei?im?lastofnun for laboratory space and logistical support. We are also grateful to Sveinbj?rn Stein?rsson of the University of Iceland for winter transport to our field sites. This work was supported in part by a Grant-In-Aid-of-Research to JRJ from Sigma-Xi (Grant ID #G20120315162084) and from the National Science Foundation (DEB-0949726 to WFC and DEB-0949774 and DEB-1354624 to JPB and ADH). Publisher Copyright: © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Other keywords
- Climate change
- Ecological stoichiometry
- Ecosystem biomass
- Flow disturbance
- Species traits
- Temperature