Bioeroding sponges are important macroborers that chemically cut out substrate particles (chips) and mechanically remove them, thereby contributing to reef-associated sediment. These chemical and mechanical proportions vary with elevated levels of partial pressure of carbon dioxide (pCO2). To assess related impacts, the morphometric parameters “chip diameter” and “etching fissure width” were analyzed for Cliona orientalis Thiele, 1900, hypothesizing that their dimensions would differ with different pCO2 exposures (72 h at ca. 400, 750 and 1700 μatm). Under ambient conditions, we obtained a mean chip diameter of 21.6 ± 0.7 μm and a mean fissure width of 0.29 ± 0.01 μm. Chips were evenly distributed across the medium and coarse silt fractions regardless of treatment. We could not find a reliable pCO2 treatment effect for chip diameter and fissure width, but we observed strong data variability not related to our key questions. A hierarchical data design further reduced the test power. Fissure width was the more sensitive, but also more variable parameter. Sample size analyses nevertheless indicated that we had processed enough data. Thus, we reject our scenario of an increase in fissure width and consequent reduction in chip size to explain why chemical sponge bioerosion increases more strongly than the mechanical counterpart. Instead, we propose that a lowered ambient pH may favor respiratory acid build-up in the sponge tissue, possibly leading to a less localized bioerosion, causing bias towards more chemical bioerosion. Overall, this does not seem to affect the morphometry of sponge chips and the quality of sponge-generated sediment.

中文翻译：

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海绵生物侵蚀与 pCO2 水溶液：碎片和蚀刻裂缝的形态测量评估

生物侵蚀海绵是重要的大孔虫，它们通过化学方式切出基质颗粒（碎片）并以机械方式去除它们，从而有助于形成与珊瑚礁相关的沉积物。这些化学和机械比例随着二氧化碳分压 (pCO2) 的升高而变化。为了评估相关影响，我们对 1900 年的 Cliona orientalis Thiele 的形态测量参数“芯片直径”和“蚀刻裂缝宽度”进行了分析，并假设它们的尺寸会随着不同的 pCO2 暴露（72 小时，大约 400、750 和 1700 μatm）而有所不同. 在环境条件下，我们获得了 21.6 ± 0.7 μm 的平均切屑直径和 0.29 ± 0.01 μm 的平均裂缝宽度。无论处理方式如何，碎屑都均匀地分布在中等和粗粒淤泥部分。我们无法找到对切屑直径和裂缝宽度的可靠 pCO2 处理效果，但我们观察到与我们的关键问题无关的强烈数据可变性。分层数据设计进一步降低了测试能力。裂隙宽度是更敏感的，但也是更可变的参数。尽管如此，样本量分析表明我们已经处理了足够的数据。因此，我们拒绝了我们的裂缝宽度增加和随之而来的芯片尺寸减小的情况，以解释为什么化学海绵生物侵蚀比机械对应物增加得更强烈。相反，我们建议降低环境 pH 值可能有利于海绵组织中呼吸酸的积聚，可能导致局部生物侵蚀减少，从而导致倾向于更多化学生物侵蚀。全面的，