Influence of sediment acidification and water flow on sediment acceptance and dispersal of juvenile soft-shell clams (Mya arenaria L.)

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• 作者：Jeff C. Clements ; ^{j.clements@unb.ca" class="auth_mail} ; Heather L. Hunt ^{hhunt@unb.ca" class="auth_mail}
• 关键词：Calcium carbonate ; Clam dispersal ; Ocean acidification ; pH ; Sediment acceptance ; Soft-shell clam
• 刊名：Journal of Experimental Marine Biology and Ecology
• 出版年：April, 2014
• 年：2014
• 卷：453
• 期：Complete
• 页码：62-69
• 全文大小：474 K

文摘

Although ocean acidification is expected to reduce carbonate saturation and yield negative impacts on open-ocean calcifying organisms in the near future, acidification in coastal ecosystems may already be affecting these organisms. Few studies have addressed the effects of sedimentary saturation state on benthic invertebrates. Here, we investigate whether sedimentary aragonite saturation (惟_aragonite) and proton concentration ([H⁺]) affect burrowing and dispersal rates of juvenile soft-shell clams (Mya arenaria) in a laboratory flume experiment. Two size classes of juvenile clams (0.5-1.5 mm and 1.51-2.5 mm) were subjected to a range of sediment 惟_aragonite and [H⁺] conditions within the range of typical estuarine sediments (惟_aragonite 0.21-1.87; pH 6.8-7.8; [H⁺] 1.58 脳 10^鈭?#xA0;8-1.51 脳 10^- 7) by the addition of varying amounts of CO₂, while overlying water pH was kept constant ~ 7.8 (惟_aragonite ~ 1.97). There was a significant positive relationship between the percent of juvenile clams burrowed in still water and 惟_aragonite and a significant negative relationship between burrowing and [H⁺]. Clams were subsequently exposed to one of two different flow conditions (flume; 11 cm s^鈭?#xA0;1 and 23 cm s^鈭?#xA0;1) and there was a significant negative relationship between 惟_aragonite and dispersal, regardless of clam size class and flow speed. No apparent relationship was evident between dispersal and [H⁺]. The results of this study suggest that sediment acidification may play an important role in soft-shell clam recruitment and dispersal. When assessing the impacts of open-ocean and coastal acidification on infaunal organisms, future studies should address the effects of sediment acidification to adequately understand how calcifying organisms may be affected by shifting pH conditions.