Year: 2017
Type: conference-paper
Abstract: Shallow lakes are usually assumed to be well-mixed but can readily stratify if submerged macrophytes are abundant. While the effects of submerged macrophytes on diurnal stratification are well documented, the role of this feedback in driving large-scale changes such as shifts in the relative dominance of macrophytes or phytoplankton has been largely neglected. Here we describe the feedback that links plant attributes to thermal stratification and physicochemical characteristics in a shallow urban lake. We used a novel approach that integrates fine-scale measurements at high spatiotemporal resolution and 3D numerical modelling to explore how plant height and biomass affect the biophysical feedbacks. Above a threshold height, submerged macrophytes strongly affected vertical mixing and horizontal exchange with surrounding unvegetated areas, resulting in bottom hypoxia. Ultimately, bottom hypoxia altered biogeochemical cycling, leading to poor water quality conditions. Macrophyte-induced stratification and the subsequent anoxia were sufficiently strong to cause central dieback, leading to the emergence of a ring-shaped pattern. By means of a deterministic mathematical model we provide additional evidence that the thermal stratification feedback can lead to pattern formation in aquatic environments. Overall, our results suggest that the potential for submerged macrophytes to induce large-scale changes in shallow lakes is more significant than previously described.
Authors: Vilas, M. P., Marti, C. L., Adams, M. P., Oldham, C. E.; id_orcid 0000-0003-2968-6889, Hipsey, M. R.
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7112956749