EAPSI: Effects of Ocean Acidification and Eutrophication on the Green Macroalgae Ulva spp

该奖项支持的研究将调查不断变化的海洋环境如何影响杂草状大型藻类石莼的生长速度。两个因素可能协同作用于石莼属。海洋酸化和富营养化是增长的主要原因。海洋酸化是由于海水对大气中二氧化碳的吸收增加，从而改变了水的化学性质，降低了pH值。已知仅富营养化就能引起石莼属的绿潮水华，据预测，海洋酸化可能会增加石莼的生长速度。因为二氧化碳的供应量增加了。当这两个因素同时发生时，它们如何影响生长速率还没有得到彻底的研究。塔斯马尼亚大学将与大型藻类生理学专家Catriona Hurd博士合作，使用最先进的海洋酸化孵化系统来研究这些影响的协同作用。海洋酸化正在世界范围内发生，人口密集的海岸附近出现富营养化。该项目将提高我们预测石莼属物种丰度的能力。海洋酸化通过增加CO2（aq）浓度改变海水化学，CO2（aq）浓度是光合作用底物Rubisco使用的碳的形式。 目前，水中溶解的CO2占海水中总无机碳的不到1%。更丰富的无机碳形式是碳酸氢盐（H2CO3）。大多数大型藻类可以利用这两种形式的无机碳进行光合作用，但是CO2的吸收能量成本较低，因为它通过被动扩散通过细胞膜发生。H2CO3的吸收需要碳吸收的能量，因此我们预测，CO2的增加可能会导致能量的节省，可以分配给生长和营养吸收。本项目将研究增加溶解的CO2是否会增加石莼的能力。进行氮的养分吸收。这项实验的结果将使我们了解人类活动和环境因素如何在海洋初级生产者未来的气候条件下相互作用。这个NSF EAPSI奖支持美国研究生的研究，并与澳大利亚科学院合作资助。

This award supports research that will investigate how the changing marine environment affects the growth rate of a weedy macroalgae, Ulva spp. Two factors that may act synergistically on Ulva spp. growth rates are ocean acidification and eutrophication. Ocean acidification is caused by increasing absorption of atmospheric carbon dioxide in seawater, which changes water chemistry and lowers pH. Eutrophication is caused mainly by human activities increasing the nutrients in seawater. Eutrophication alone is known to cause green-tide blooms of Ulva spp., and it is predicted that ocean acidification may increase growth rates of Ulva spp. because of increased carbon dioxide availability. How these two factors affect the growth rate when occurring simultaneously has not been thoroughly investigated. A state of the art ocean acidification incubation system will be used to investigate the synergy of these effects at the University of Tasmania in collaboration with Dr. Catriona Hurd, an expert in macroalgal physiology. Ocean acidification is occurring worldwide and eutrophication occurs near heavily populated coasts. This project will increase our ability to make predictions about the abundance of Ulva spp. in future marine environments.Ocean acidification changes seawater chemistry by increasing the CO2(aq) concentration, which is the form of carbon used by the photosynthetic substrate Rubisco. Presently, dissolved CO2 in water makes up less than 1% of the total inorganic carbon in seawater. The more abundant form of inorganic carbon is bicarbonate (H2CO3). Most macroalgae can utilize both forms of inorganic carbon for photosynthesis, however the uptake of CO2 is less energetically costly as it occurs via passive diffusion through the cell membrane. Uptake of H2CO3 requires energy for carbon uptake, so we predict that the increase in CO2 may result in energetic savings that can be allocated to growth and nutrient uptake. This project will investigate if increasing dissolved CO2 will increase the ability of Ulva spp. to perform nutrient uptake of nitrogen. The results of this experiment will inform us about how human activities and environmental factors interact in future climate conditions for marine primary producers. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Australian Academy of Science.