Nutrients influence the thermal ecophysiology of an intertidal macroalga: multiple stressors or multiple drivers?
Nutrients influence the thermal ecophysiology of an intertidal macroalga: multiple stressors or multiple drivers?
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DOI：
10.1002/eap.1475
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发表时间：
2017-01-01
影响因子：
5
通讯作者：
Helmuth, Brian
中科院分区：
文献类型：
--
作者：
Colvard, Nicholas;Helmuth, Brian
海岸线的城市化导致陆地环境中的养分越来越多地引入近岸栖息地。虽然由于富营养化加剧和随后的氧气减少，这种营养物流入可能对沿海海洋生物有害，但它们也可能对大型藻类等限氮物种产生积极影响（即增加食物供应）。因此，这种环境中的营养富集有可能抵消温度升高的一些负面影响，至少对某些物种来说是这样。表征生物体对多种驱动因素同时变化的生理反应，是预测全球气候变化如何导致更局部层面生态反应的重要第一步。我们评估了营养富集（即氮的可用性）如何影响墨角藻（北大西洋岩石潮间带的一种基本大型藻类）的生长，发现与在环境条件下生长的个体相比，营养丰富的藻类叶片的组织生长显着增加。我们进一步量化了在一定温度条件（6-30 摄氏度）下饱和辐照度下环境和营养丰富的组织的净光合作用。呼吸不受营养处理的影响；然而，与环境相比，营养丰富的组织的光合产氧量显着增加，但仅限于升高的温度（18 摄氏度）。这项研究有助于越来越多的文献展示对多种驱动因素变化的反应的复杂性，并强调在更多当地环境条件的背景下研究全球气候变化影响的重要性。
Urbanization of coastlines is leading to increased introduction of nutrients from the terrestrial environment to nearshore habitats. While such nutrient influxes can be detrimental to coastal marine organisms due to increased eutrophication and subsequent reduced oxygen, they could also have positive effects (i.e., increased food availability) on species that are nitrogen-limited such as macroalgae. Nutrient enrichment in this environment thus has the potential to counteract some of the negative impacts of increasing temperatures, at least for some species. Characterizing the physiological response of organisms to simultaneous changes in multiple drivers such as these is an important first step in predicting how global climate change may lead to ecological responses at more local levels. We evaluated how nutrient enrichment (i.e., nitrogen availability) affected the growth of Fucus vesiculosus, a foundational macroalgal species in the North Atlantic rocky intertidal zone, and found that nutrient-enriched algal blades showed a significant increase in tissue growth compared to individuals grown under ambient conditions. We further quantified net photosynthesis by ambient and nutrient-enriched tissues at saturating irradiance over a range of temperature conditions (6-30 degrees C). Respiration was unaffected by nutrient treatment; however, there was a significant increase in photosynthetic oxygen production for nutrient-enriched tissue compared to ambient, but only at elevated (18 degrees C) temperatures. This study contributes to a growing body of literature showing the complexity of responses to changes in multiple drivers, and highlights the importance of studying the impacts of global climate change within the context of more local environmental conditions.