Abstract：
Gigaton scale atmospheric carbon dioxide (CO2) removal (CDR) is needed to keep global warming below 1.5 °C. Coastal enhanced olivine weathering is a CDR technique that could be implemented in coastal management programmes, but its CO2 sequestration potential and environmental safety remain uncertain. Large scale olivine spreading would change the surficial sediment characteristics, which could potentially reduce habitat suitability and ultimately result in community composition changes. To test this hypothesis, we investigated the avoidance response of the marine gastropod Littorina littorea (Linnaeus, 1758) and marine amphipod Gammarus locusta (Linnaeus, 1758) to relatively coarse (83 - 332 µm) olivine and olivine-sediment mixtures during short-term choice experiments. Pure olivine was significantly avoided by both species, while no significant avoidance was observed for sediment with 3% or 30% w/w olivine. For L. littorea, aversion of the light green colour of pure olivine (i.e. positive scototaxis) was the main reason for avoidance. Moreover, olivine was not significantly avoided when it was 7.5 cm (45%) closer to a food source/darker microhabitat (Ulva sp.) compared to natural sediment. It is inferred that the amphipod G. locusta avoided pure olivine to reduce Ni and Cr exposure. Yet, a significant increase in whole body Ni concentrations was observed after 79 h of exposure in the 30% and 100% w/w olivine treatments compared to the sediment control, likely as a result of waterborne Ni uptake. Overall, our results are significant for ecological risk assessment of coastal enhanced olivine weathering as they show that L. littorea and G. locusta will not avoid sediments with up to 30% w/w relatively coarse olivine added and that the degree of olivine avoidance is dependent on local environmental factors (e.g. food or shelter availability).
摘要：
需要千兆级大气二氧化碳（CO2）去除（CDR）才能将全球变暖保持在1.5°C以下。沿海增强橄榄石风化是一种CDR技术，可以在沿海管理计划中实施，但其二氧化碳封存潜力和环境安全性仍不确定。大型橄榄石扩散会改变表层沉积物特征，这可能会降低栖息地的适宜性，并最终导致群落组成的变化。为了检验这个假设，我们调查了海洋腹足动物Littorinalittorea(Linnaeus，1758年)和海洋两栖动物Gammaruslocusta(Linnaeus，1758）在短期选择实验中相对较粗（83-332µm）的橄榄石和橄榄石-沉积物混合物。纯橄榄石被两个物种显著避免，而对于含有3%或30%w/w橄榄石的沉积物，没有观察到明显的回避。对于Littorea,对纯橄榄石的浅绿色（即正scootaxis）的厌恶是避免的主要原因。此外，当橄榄石更靠近食物来源/较暗的微生境7.5厘米（45％）时，并没有明显避免橄榄石（Ulvasp.)与天然沉积物相比。推断两栖动物G.蝗虫避免了纯橄榄石以减少Ni和Cr的暴露。然而，与沉积物对照相比，在30％和100％w/w橄榄石处理暴露79小时后，观察到全身Ni浓度显着增加，可能是水性镍吸收的结果。总的来说,我们的结果对于沿海增强橄榄石风化的生态风险评估具有重要意义，因为它们表明，L.littorea和G.locusta不会避免沉积物添加多达30％w/w相对粗橄榄石，并且橄榄石的避免程度取决于当地的环境因素（例如食物或住所的可用性）。
