Algal-Induced Biogeomorphic Feedbacks Lay the Groundwork for Coastal Wetland Development
van de Vijsel, Roeland C.; van Belzen, Jim; Bouma, Tjeerd J.; van der Wal, Daphne; van de Koppel, Johan
(2021) Journal of Geophysical Research: Biogeosciences, volume 126, issue 10, pp. 1 - 17
(Article)
Abstract
Ecosystem establishment under adverse geophysical conditions is often studied within the “windows of opportunity” framework, identifying disturbance-free periods (e.g., calm wave climate) where species can overcome establishment thresholds. However, the role of biogeophysical interactions in this framework is less well understood. The establishment of saltmarsh vegetation on tidal flats, for
... read more
example, is limited by abiotic factors such as hydrodynamics, sediment stability and drainage. On tidal flats, raised sediment ridges colonized by algal mats (Vaucheria sp.) appear to accomodate high densities of plant seedlings. Such ridges were previously found to have higher sediment strength than substratum without algae. Here, we investigate whether these measurements can be explained by geophysical factors only, or that biological (Vaucheria-induced) processes influence tidal marsh establishment by forming stabilized bedforms. We performed two experiments under controlled mesocosm conditions, to test the hypotheses that (a) Vaucheria grows better on elevated topographic relief, that (b) the binding force of their algal filaments increases sediment strength, and that (c) Vaucheria consequently creates elevated topographic relief that further facilitates algal growth. Our experimental results confirm the existence of this algal-induced biogeomorphic feedback cycle. These findings imply that benthic algae like Vaucheria may contribute significantly to tidal marsh formation by creating elevated and stabilized substratum. This suggests biogeophysical feedbacks can “widen” the windows of opportunity for further ecosystem establishment. Our results could be useful for the design of managed realignment projects aimed at restoring the unique ecosystem services of coastal wetlands, such as habitat biodiversity, carbon sequestration potential and nature-based flood defense.
show less
Download/Full Text
Keywords: algae, biogeophysics, coastal wetlands, drainage, sediment strength, vegetation, Soil Science, Forestry, Water Science and Technology, Palaeontology, Atmospheric Science, Aquatic Science, Ecology
ISSN: 2169-8953
Publisher: Wiley-Blackwell Publishing Ltd
Note: Funding Information: The authors wish to thank Lennart van IJzerloo, Jeroen van Dalen, Daniel B. Blok, Bert Sinke, Arne den Toonder and Lowie Haazen for their assistance during the setup of the experiments. Vincent van Belzen helped during the installation of Experiment 1. We acknowledge Yvonne van der Maas, Peter van Breugel and Jan Peene for their help with the analyses of chlorophyll-a and organic carbon content and tank water chemistry. The work of RCvdV was funded by the program ?The New Delta? (project number 869.15.003) of the Netherlands Organisation for Scientific Research (NWO). The work of JvB was funded by the Vlaams-Nederlandse Scheldecommissie (VNSC) project ?Vegetation modelling HPP? (contract 3109 1805). Funding Information: The authors wish to thank Lennart van IJzerloo, Jeroen van Dalen, Daniel B. Blok, Bert Sinke, Arne den Toonder and Lowie Haazen for their assistance during the setup of the experiments. Vincent van Belzen helped during the installation of Experiment 1. We acknowledge Yvonne van der Maas, Peter van Breugel and Jan Peene for their help with the analyses of chlorophyll‐a and organic carbon content and tank water chemistry. The work of RCvdV was funded by the program “The New Delta” (project number 869.15.003) of the Netherlands Organisation for Scientific Research (NWO). The work of JvB was funded by the Vlaams‐Nederlandse Scheldecommissie (VNSC) project “Vegetation modelling HPP” (contract 3109 1805). Publisher Copyright: © 2021. The Authors.
(Peer reviewed)
See more statistics about this item