光谱质量和光子照度对酸化环境中珊瑚代谢的影响

Role of Light Intensity and Spectral Quality in the OA-induced Metabolic Responses of Coral

以霜鹿角珊瑚(Acropora pruinosa)、稀杯盔形珊瑚(Galaxea astreata)、盾形陀螺珊瑚(Turbinaria peltata)为研究对象,研究光照对酸化环境中的珊瑚钙化的调节作用。结果表明,光照条件下,随着p H降低,光照钙化率(G_L)下降,且光子照度越低钙化率越低;酸化环境中,不同光谱低光强(LL)条件下G_L、G_L/GD(暗环境钙化率)比值小于高光强(HL)环境,G_L变化率大于HL环境,稀杯盔形珊瑚尤为明显,酸化对石珊瑚G_L的影响在高光强环境(HL)中受抑制。酸化环境中霜鹿角珊瑚总光合作用效率(P_G)在HL条件下降低速率明显小于LL,稀杯盔形珊瑚和盾形陀螺珊瑚则无差异,光子照度对酸化环境中不同珊瑚的P_G调节效果不同;G_L和P_G、G_L变化率和P_G变化率间的线性相关性显示HL加强了P_G,且可能加强G_L,由于P_G可能受限于pCO_2,且HL条件下,酸化减缓了pCO_2对P_G的抑制作用。低光子照度下珊瑚对酸化环境比较敏感。

We employed a multifactorial growth experiment to determine how light intensity and OAtogether modify the calcification of Acropora pruinosa,Galaxea astreata and Turbinaria peltata. It wasfound that decreased pH(OA)-induced losses of calcification in the light (GL) especially underlow-light growth conditions. The influence of light intensity upon gross photosynthesis(PG)onses iscoral species specific. Under light-limited growth conditions GL,GL / GD with OA was lower than thatgrowth under high-light and with different spectral quality,but the change of GL with OA was higherthan that of under high-lightcondition,in particular for Galaxea astreata. Those results suggested thathigh-light growth conditions dampened the impact of OA upon GL. OA-induced change of PG onlight-saturated growth(LL)was significantly smaller than LL for Acropora pruinosa,and did not showa significant differences between high light(HL)and low light(LL)for Galaxea astreata,Turbinariapeltata. The reciprocal OA-induced change of GL with PG and change of GL with PG are consistent with the notion that PG is enhanced by HL and GL is enhanced by PG,which is fundamentally limited bypCO2 availability (and hence relieved by OA) under HL. In total,this study suggests that lower lightavailability will potentially increase the susceptibility of key coral species to OA.