【摘要】 为探讨海洋酸化和光照强度变化对海洋钙化生物的影响,本文选用广泛分布在热带珊瑚礁区的大型钙化海藻仙掌藻(Halimeda opuntia)为研究对象,在室内通过CO2加富(pH=7.50、7.80和8.10)和调控光照强度(30和180μmol photons m2·s-1)的方式,探究其生长、钙化作用和光合作用等生理特征对海洋酸化和光照强度变化的响应。结果表明:海水酸化可以显著抑制仙掌藻的生长率、钙化速率和光合效率,且随酸化程度的加深而加强。酸化条件下(p H 7.50～7.80),生长率、钙化速率和Fv/Fm分别下降了48.29%～58.80%、51.78%～62.29%和2.37%～13.79%;光照强度的增加可以缓解这一抑制作用,高光照下生长率、钙化速率和Fv/Fm分别升高了2.01%～44.55%、29.61%～40.68%和1.68%～6.92%。酸化处理和光照强度变化对色素含量、丙二醛(MDA)和脯氨酸含量影响显著(P <0.01);酸化处理组中的Chl-a含量下降了32.69%～43.44%;而实验第20-28天,低光条件下的类胡萝卜素含量比高光照组高出12.12%～57.45%;酸化胁迫下,MDA在组织中逐渐积累;同时脯氨酸明显升高,以增加藻体自身的抗逆性,缓解胁迫带来的损伤。此外,组织中总碳(TC)和总氮(TN)含量在酸化条件下显著增加(P <0.05),光照强度的增加也一定程度上有利于提高TC和TN含量。通过分析可知,海洋酸化对仙掌藻的威胁是多方面的,对其生长、钙化作用和光合作用等生理过程的抑制作用随着酸化程度的加深而增加,而光照强度的增加一定程度上可以缓解酸化带来的负面效应。这些结果可以为预测未来海洋酸化对钙质生物的影响和珊瑚礁生物的多样性保护提供理论参考。更多还原

【Abstract】 While various responses of tropical calcifying species to ocean acidification have been widely reported, the modulating potential of irradiance combined with elevated p CO2 is not well studied. The interactive effects of ocean acidification(pH=7.50, 7.80 and 8.10) and irradiance intensities(30 and 180 μmol photons m2·s-1) on the physiology of calcifying green macroalgae Halimeda opuntia were investigated using a fully factorial, 28-day aquaria experiment. The results revealed that the specific growth rate(SGR), net calcification rates(Gnet) and the maximum quantum yield(Fv/Fm) of H. opuntia decreased by 48.29 %～58.80 %, 51.78 %～62.29 % and 2.37 %～13.79 %, respectively, in T1 and T2 treatments. However,when exposed to 180 μmol photons m-2 s-1, SGR, Gnetand Fv/Fm increased by 2.01 %～44.55 %, 29.61 %～40.68 % and1.68 %～6.92 % in two elevated p CO2 treatments. Chl-a contents in elevated p CO2 treatments showed 32.69 %～43.44 % lower than those in ambient p CO2 under high irradiance conditions after 28-day incubation, while the carotenoid content differed depending on elevated p CO2 and irradiance intensities(P < 0.01), which increased by 12.12 %～57.45 % at low irradiance on20～28-day. The malondialdehyde(MDA) content, which was measured every 4 days to evaluate the levels of abiotic stresses,showed higher in elevated p CO2 treatments. However, there were also 2～4 folds increase of proline contents in elevated p CO2 treatments which contributed to protection of membranes from various damages. Tissue total carbon(TC) and nitrogen(TN)was positively correlated to CO2 enrichment(P < 0.05). These results suggested that elevated p CO2 negatively influenced the physiological responses of H. opuntia from contrasting with different irradiance treatments and increasing irradiance intensity may serve to enhance the metabolic performance to ocean acidification in certain cases. Furthermore, the results of present study could provide a theoretical basis for protection of ecological diversity and sustainable development of coral reef ecosystems.更多还原