Globally enhanced calcification across the coccolithophore Gephyrocapsa complex during the mid-Brunhes interval
Globally enhanced calcification across the coccolithophore Gephyrocapsa complex during the mid-Brunhes interval
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DOI：
10.1016/j.quascirev.2023.108375
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发表时间：
2023-12
影响因子：
4
通讯作者：
A. González-Lanchas;R. Rickaby;F. Sierro;A. Rigual-Hernández;M. Alonso-García;José A. Flores
中科院分区：
文献类型：
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作者：
A. González-Lanchas;R. Rickaby;F. Sierro;A. Rigual-Hernández;M. Alonso-García;José A. Flores
在更新世低轨道偏心率时期，Noelaerhabdaceae颗石藻的进化或适应性变化与碳酸盐输出和埋藏的重大变化同时发生，周期性为400 kyr。在这些增强增殖的条件下，我们报告了在Mid-Brunhes （MB）期间，标本的钙化在全球范围内以及在gephyrocapsac复合体内的多个物种或形态中都得到了增强。这种由gephyrocapsa产生的有机和无机碳的峰值表明，这种全球变化可能源于一个共同的驱动因素。海水碱度的增加，以及适当长的停留时间，被认为是多种高钙化和高增殖的藻椒科植物选择的环境触发因素。这一新的观点强调了轨道强迫在浮游植物进化或适应中的作用，通过海水碳化学形式的全球环境驱动因素。我们的结果符合早期的建议呼吁加强生物泵和呼吸溶解在这段时间内。我们假设gephyrocapsaacme可能发挥了双重作用，通过增加浅呼吸溶解速率，限制通过掩埋去除碱度，这可能有助于碱度的再循环并保持在~ 400 kyr尺度上的恒定水平。这一观点表明，新藻科球石藻具有改变海洋中典型碳酸盐补偿行为的潜在能力，并且球石藻钙化的变化可能指示了过去海洋碳酸盐化学的变化和全球碳循环的运作。
Evolutionary or adaptative changes in Noelaerhabdaceae coccolithophores occurred in parallel with major changes in carbonate export and burial during scenarios of low orbital eccentricity, with a ∼400 kyr recurrence, during the Pleistocene. Coeval with these conditions of enhanced proliferation, here we report that the calcification of specimens was enhanced at a global scale and across multiple species or morphotypes within theGephyrocapsacomplex during the Mid-Brunhes (MB) interval. This acme of increased production of organic and inorganic carbon byGephyrocapsa, suggests that such global changes may originate from a common driver. Increased seawater alkalinity, with an appropriately long residence time, is proposed as environmental trigger on the selection of a wide variety of highly calcified and prolificGephyrocapsataxa. This new perspective highlights the role of orbital forcing in phytoplankton evolution or adaptation, via a global environmental driver in the form of seawater carbon chemistry. Our results fit with earlier proposals appealing for an intensified biological pump and respiration dissolution during this interval. We hypothesize that theGephyrocapsaacme may play adouble-edgedrole, by increasing shallow respiration dissolution rates, limiting the removal of alkalinity by burial, which may help to recycle alkalinity and maintain constant levels at the ∼400 kyr scale. This idea suggests the potential capacity of the Noelaerhabdaceae coccolithophore acmes to modify the typical behaviour of carbonate compensation in the ocean and that the changes in coccolithophore calcification may be indicative of changes in ocean carbonate chemistry and the operation of the global carbon cycle in the past.