海水铝浓度对海链藻活性、生产力及其固碳性的影响

近年来,随着人类工业活动的增多及强淋溶性酸雨的频繁出现,大量的铝被输入到海洋中,导致海水环境中铝浓度的急剧增加.由于可溶性铝对绝大多数水生生物具有生物毒害性,其浓度的增加势必将影响到水生生物,尤其是对环境变化较为敏感的水生植物等的生命活动及其所涉及的元素地球化学循环作用.作为全球生产力的主要贡献者,硅藻提供了40％的海...

Effects of aluminum concentration in seawater on the activity, productivity, and carbon sequestration of Thalassiosira weissflogii

Recently,huge amounts of aluminum(Al)have been imported into oceans due to increasing industrial activities and intensive eluviation of soils and rocks by acid rain,thus consequently resulting in a rapid increase of Al concentration in seawater.The biological activity and related biological driven geochemical cycling of most aquatic organisms that are sensitive to environmental changes will consequently be influenced by such Al concentrations increment,given the biological toxicity of Al.As an important contributor to global productivity,diatoms provide 40%of marine primary productivity and regulate the global carbon cycle through a“biological pump.”However,whether the increase in aluminum concentration in seawater will affect its biological activities and its carbon sequestration capacity remains unclear.In this study,we aimed to investigate the effect and mechanism of Al concentrations on biological activity and productivity of one marine diatom and its driven biogeochemical cycle of carbon.Thalassiosira weissflogii,a typical offshore diatom,was selected as a model of marine diatoms and cultured in Al-rich medium.Results showed no toxic effect on Thalassiosira weissflogii when Al concentrations were≤50 nmol/L.Nonetheless,these Al concentrations resulted in an increase in primary productivity of the model diatom(Thalassiosira weissflogii).However,the carbon sequestration capacity of the model diatom is varied with different Al concentrations,such that,when it was 20 nmol/L,carbon sequestration capacity of the diatom was higher than when Al was not added.Moreover,Al was taken up by biological behaviors of the diatom and used as a framework element to build siliceous shells.These fundamental results show that Al concentration in seawater has a significant effect on biological activity of diatoms.When the concentration reaches a certain threshold,it significantly decreases the carbon sequestration capacity of diatoms,thus affecting the global role of diatom in the“biological pump.”