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On October 22, 2024, 9:47:21 AM UTC, Gravatar ckan_admin:

  • Updated description of Algal-Induced Biogeomorphic Feedbacks Lay the Groundwork for Coastal Wetland Development from

    Ecosystem establishment under adverse geophysical conditions is often studied within the framework of windows of opportunity, which predicts ecosystems to establish when geophysical disturbances are temporarily reduced. However, the role of biogeophysical interactions in this framework is less well understood. The establishment of saltmarsh vegetation on tidal flats, for example, is limited by abiotic factors such as hydrodynamics, sediment stability and drainage. On tidal flats, we observe high densities of plant seedlings on raised sediment ridges colonized by algal mats (Vaucheria sp.). Such ridges were previously found to have higher sediment strength than substrate 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 perform two experiments under controlled mesocosm conditions, to test the hypotheses that i) Vaucheria grows better on elevated topographic relief, ii) the binding force of their algal filaments increases sediment strength, which consequently iii) creates elevated topographic relief that further facilitates algal growth. Our experimental results confirm the existence of this algal-induced biogeomorphic feedback cycle. These findings reveal that primitive organisms like Vaucheria may contribute significantly to tidal marsh formation by creating elevated and stabilized substrate. We thus show that 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.
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    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 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 i) Vaucheria grows better on elevated topographic relief, that ii) the binding force of their algal filaments increases sediment strength, and that iii) 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.


  • Changed the version of Algal-Induced Biogeomorphic Feedbacks Lay the Groundwork for Coastal Wetland Development to 4 (previously 3)