Abstract The processes affecting diatom dissolution and upper water column silica recycling are understood in modern environments. However, few studies have been undertaken to understand which processes have the greatest impact on diatom preservation in sedimentary archives. Furthermore, variability in diatom dissolution in the upper water column of past oceans is rarely quantified. Here we present a record of diatom dissolution, a proxy for upper water column silica recycling, from the Pliocene of the Ross Sea. Dissolution was quantified utilizing diatoms from the AND-1B core. These data were related to previously published diatom proxies of sea surface conditions. Diatoms were found to be better preserved in intervals dominated by sea ice diatoms than intervals dominated by cosmopolitan open ocean diatoms. However, preservation was not constant in the interval dominated by cosmopolitan diatoms, implying another taphonomic control. An antiphase relationship was found between diatom-inferred water temperature and dissolution; dissolution is less during cold intervals. A weaker positive correlation was found between diatom accumulation and preservation; dissolution is lower during periods of high diatom accumulation. The relationship between diatom accumulation and preservation reflects pore water saturation; individual diatoms contributes less silica to pore water saturation. However, increased growth rate is expected to result in thinner frustules and increased dissolution. These two opposing factors explain the weakness of the observed correlation. Interestingly, these results are different from those found in other Southern Ocean sediment cores. Comparative analysis highlights the importance of taphofacies on diatom preservation in understanding diatom dissolution data.

中文翻译：

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来自AND-1B钻芯的硅藻保存记录：火泥相对硅藻保存的意义

摘要 在现代环境中了解影响硅藻溶解和上水柱二氧化硅回收的过程。然而，很少有研究了解哪些过程对沉积档案中的硅藻保存影响最大。此外，过去海洋上层水体中硅藻溶解的变化很少被量化。在这里，我们展示了来自罗斯海上新世的硅藻溶解记录，这是上水柱二氧化硅回收的代表。利用来自 AND-1B 核心的硅藻对溶解进行量化。这些数据与先前公布的海面条件硅藻代理有关。发现在以海冰硅藻为主的区间中，硅藻比以国际化的公海硅藻为主的区间保存得更好。然而，在世界性硅藻占主导地位的区间内，保存并不是恒定的，这意味着另一种埋藏控制。发现硅藻推断水温与溶解之间存在反相关系；在冷间隔期间溶解较少。发现硅藻积累与保存之间存在较弱的正相关；在高硅藻积累期间溶解较低。硅藻积累与保存的关系反映了孔隙水饱和度；单个硅藻对孔隙水饱和度的贡献较少。然而，预计增加的生长速率会导致更薄的硅藻壳和增加的溶解。这两个相反的因素解释了观察到的相关性的弱点。有趣的是，这些结果与在其他南大洋沉积岩心中发现的结果不同。