Viana Inés G, Moreira-Saporiti Agustín, Teichberg Mirta
Department of Ecology and Animal Biology, University of Vigo, Vigo, Spain.
Leibniz Centre for Tropical Marine Research GmbH, Bremen, Germany.
Front Plant Sci. 2020 Nov 5;11:571363. doi: 10.3389/fpls.2020.571363. eCollection 2020.
Seagrass meadows are declining globally. The decrease of seagrass area is influenced by the simultaneous occurrence of many factors at the local and global scale, including nutrient enrichment and climate change. This study aims to find out how increasing temperature and nutrient enrichment affect the morphological, biochemical and physiological responses of three coexisting tropical species, , and . To achieve these aims, a 1-month experiment under laboratory conditions combining two temperature (maximum ambient temperature and current average temperature) and two nutrient (high and low N and P concentrations) treatments was conducted. The results showed that the seagrasses were differentially affected by all treatments depending on their life-history strategies. Under higher temperature treatments, showed photo-acclimation strategies, while showed decreased photo-physiological performance. In contrast, was resistant to nutrient over-enrichment, showing enhanced nutrient content and physiological changes, but suffered BG nutrient loss. The limited response of to nutrient enrichment or high temperature suggests that this seagrass is a tolerant species that may have a dormancy state with lower photosynthetic performance and smaller-size individuals. Interaction between both factors was limited and generally showed antagonistic effects only on morphological and biochemical traits, but not on physiological traits. These results highlight the different effects and strategies co-inhabiting seagrasses have in response to environmental changes, showing winners and losers of a climate change scenario that may eventually cause biodiversity loss. Trait responses to these stressors could potentially make the seagrasses weaker to cope with following events, due to BG biomass or nutrient loss. This is of importance as biodiversity loss in tropical seagrass ecosystems could change the overall effectiveness of ecosystem functions and services provided by the seagrass meadows.
全球范围内，海草草甸正在减少。海草面积的减少受到地方和全球尺度上多种因素同时出现的影响，包括营养物质富集和气候变化。本研究旨在探究温度升高和营养物质富集如何影响三种共存的热带海草物种，即[物种名称1]、[物种名称2]和[物种名称3]的形态、生化和生理反应。为实现这些目标，在实验室条件下进行了为期1个月的实验，该实验结合了两种温度（最高环境温度和当前平均温度）和两种营养物质（高氮磷浓度和低氮磷浓度）处理。结果表明，根据其生活史策略，所有处理对海草的影响各不相同。在较高温度处理下，[物种名称1]表现出光适应策略，而[物种名称2]的光生理性能下降。相比之下，[物种名称3]对营养物质过度富集具有抗性，表现为营养物质含量增加和生理变化，但[物种名称4]遭受了BG营养物质损失。[物种名称5]对营养物质富集或高温的有限反应表明，这种海草是一种耐受性物种，可能具有较低光合性能和较小个体的休眠状态。两种因素之间的相互作用有限，通常仅对形态和生化特征表现出拮抗作用，而对生理特征没有影响。这些结果突出了共存海草对环境变化的不同影响和策略，显示了气候变化情景下可能最终导致生物多样性丧失的赢家和输家。由于BG生物量或营养物质损失，对这些压力源的性状反应可能会使海草在应对后续事件时变得更脆弱。这一点很重要，因为热带海草生态系统中的生物多样性丧失可能会改变海草草甸提供的生态系统功能和服务的整体有效性。
