Flow velocity and light level drive non-linear response of seagrass Zostera noltei to ammonium enrichment
Villazán, B.; Brun, F.G.; Moreno-Marín, F; Bouma, T.J.; Vergara, J.J. (2016). Flow velocity and light level drive non-linear response of seagrass Zostera noltei to ammonium enrichment. Mar. Ecol. Prog. Ser. 545: 109–121. https://dx.doi.org/10.3354/meps11631
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630; e-ISSN 1616-1599, more
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| Keyword |
Zostera noltei Hornemann, 1832 [WoRMS]
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| Author keywords |
Ammonium toxicity; Flume tank; Hydrodynamics; Light reduction; Multiple stressors; Seagrass; Zostera noltei |
| Authors | | Top |
- Villazán, B.
- Brun, F.G.
- Moreno-Marín, F
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- Bouma, T.J., more
- Vergara, J.J.
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| Abstract |
We investigated the interactive effects of light (low and high light doses) and flowvelocity (low, medium and high levels) under NH4+ enriched conditions on dynamic and morphologicalvariables of Zostera noltei plants in a 5 wk flume experiment. Our results showed a nonlinearresponse of Z. noltei in this factorial design, with the strongest negative effect of NH4+enrichment recorded at intermediate flow velocities for almost all the dynamic response variables(i.e. survival, net production, shoot appearance rate). This negative effect of NH4+ enrichment wasintensified under low light conditions, where net production was only positive in plants growingat high flow velocity. This positive effect of flow velocity was ascribed to the more horizontal positionof the leaves, which allows for higher levels of light capture than under lower flow velocities.However, enhancing current velocity may increase NH4+ uptake rates until they reach adverselevels, which can potentially trigger NH4+ toxicity. This negative effect of flow velocity seems to beneutralized by the higher light capture at high flow, resulting in intermediate current velocitiesbeing more harmful for plants. In summary, our results highlight the importance of studying thecomplexity of interactions among multiple stressors that frequently co-occur in nature to improveour ability to forecast the response of seagrass populations to possible interaction effects in futureglobal change scenarios. |
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