變遷海洋中的幼生烏賊：海洋酸化、暖化及微塑膠汙染對其生長及行為之探討

Abstract

氣候變遷和環境污染正對海洋生態系統構成嚴峻挑戰，海洋酸化、暖化及微塑膠汙染是其中重要的環境壓力源。過去研究觀察到頭足類在氣候變遷下族群有上升趨勢，然而近年來區域性頭足類漁獲量的下降，引起了頭足類能否在多重環境壓力影響下生存的疑慮。此外生物早期生命階段的脆弱性與行為改變可能會影響到後續族群延續，因此本研究選擇孵化後一週及四週的幼生虎斑烏賊作為實驗動物，設計六組條件：控制組、酸化組、暖化組、微塑膠組、酸暖化組、酸暖化微塑膠組，以釐清暖化、酸化和微塑膠對幼生烏賊的影響，各組均透過捕食行為實驗、耗氧實驗、測量外套膜長和溼重來了解其行為、代謝和生長表現情況。研究發現，在捕食行為方面，雖然暴露在暖化環境中會導致幼生虎斑烏賊孵化一週後所需的捕食時間增加，但到了孵化後四週，各組之間所需的捕食時間表現並沒有顯著差異；暖化和微塑膠環境下會使幼生虎斑烏賊代謝增加，而暴露在酸化下則減緩了代謝表現；暴露在酸化和微塑膠污染的環境下，會對孵化後四週幼生虎斑烏賊溼重產生顯著負面影響，分別下降13%、15%。本研究證實，氣候變遷及環境污染可能會給幼生虎斑烏賊帶來相關的生理挑戰，但其捕食能力並不容易受到破壞。本研究為理解多重環境壓力源對幼生虎斑烏賊的影響提供了重要依據，可以更全面地理解在未來變遷海洋中頭足類動物如何反應及適應。

Climate change and environmental pollution pose significant challenges to marine ecosystems, with ocean acidification, warming, and microplastic pollution being significant environmental stressors. Previous studies observed an increase in cephalopod populations under climate change. However, recent declines in regional cephalopod catches have raised concerns about their ability to survive under multiple environmental stressors. Additionally, the vulnerability and behavioral changes during early life stages of organisms could impact subsequent population sustainability. Therefore, this study focused on juvenile pharaoh cuttlefish (Sepia pharaonis) at one and four weeks after hatching. Six experimental conditions were designed: control, acidification, warming, microplastic, acidification-warming, and acidification-warming-microplastic, to clarify the effects of warming, acidification, and microplastic on juvenile cuttlefish. Each group was evaluated for predation behavior, metabolism, and growth performance through predation behavior experiments, oxygen consumption experiments, and measurements of mantle length and wet weight. The results revealed that while exposure to warming environments increased the time required for one-week-old juvenile pharaoh cuttlefish to catch prey, there were no significant differences in predation behavior among groups by four weeks after hatching. Both warming and microplastic environments led to increased metabolism, whereas exposure to acidification reduced metabolic performance. Moreover, exposure to acidification and microplastic pollution significantly reduced the wet weight of four-week-old juvenile pharaoh cuttlefish by 13% and 15%, respectively. This research confirms that climate change and environmental pollution may pose physiological challenges to juvenile pharaoh cuttlefish, but their predation abilities remain relatively unaffected. This study provides crucial insights into understanding the impacts of multiple environmental stressors on juvenile pharaoh cuttlefish. It offers a comprehensive understanding of how cephalopod may respond and adapt to future changing ocean.