Intermittent bioirrigation and oxygen dynamics in permeable sediments: An experimental and modeling study of three tellinid bivalves
Intermittent bioirrigation and oxygen dynamics in permeable sediments: An experimental and modeling study of three tellinid bivalves
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DOI：
10.1357/002224012806770955
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发表时间：
2012-11
影响因子：
0.5
通讯作者：
N. Volkenborn;C. Meile;L. Polerecky;C. Pilditch;A. Norkko;J. Norkko;J. Hewitt;S. Thrush;D. Wethey;S. Woodin
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文献类型：
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作者：
N. Volkenborn;C. Meile;L. Polerecky;C. Pilditch;A. Norkko;J. Norkko;J. Hewitt;S. Thrush;D. Wethey;S. Woodin
为了探索生物灌溉海洋渗透性沉积物中地球化学条件的动态性质，我们研究了三种泰利纳类双壳软体动物（太平洋物种Macoma nasuta和Macomona liliana，以及北方大西洋和太平洋物种Macoma balth-ica）的水力活动。我们结合孔隙水压力传感，延时摄影和氧气成像，量化的时间和频率的tellinid灌溉活动和相关的沉积物中的氧动力学。孔隙水压力记录的所有tellinids占主导地位的间歇性孔隙水加压，诱导定期注水到沉积物通过其excurrent虹吸管，这导致间歇性的氧气供应到地下沉积物。灌水时间（2 ~ 12分钟）和灌水间隔（1.5 ~ 13分钟），对不同种类、不同大小的石首鱼均有不同的影响。liliana和M. nasuta时，灌水间隔时间较长（分别为10 min和4 min），能使所有试验沉积物类型的灌水间隔完全耗氧。balthica的特点是灌溉间隔时间大大缩短，从而使沉积物的氧化作用更加连续。运输-反应模型证实了这些物种和大小特异性的地球化学特征，并表明沉积物的地球化学特征在很大程度上取决于时间灌溉模式和沉积物耗氧率之间的相互作用。对于大的碲铋矿，模型模拟表明，振荡，而不是固定的地球化学条件普遍存在于各种各样的沉积物类型，与氧化口袋之间的积极灌溉期间完全崩溃。基于模型的结果，我们开发了分析近似值，可以估计的时空特征的沉积物氧化的沉积物类型和底栖动物的活动模式的范围很广。我们的研究结果强调，需要考虑间歇性的生物灌溉时，在渗透性沉积物中的底栖动物的地球化学影响的研究。
To explore the dynamic nature of geochemical conditions in bioirrigated marine permeable sediments, we studied the hydraulic activity of three tellinacean bivalve molluscs (the Pacific species Macoma nasuta and Macomona liliana , and the northern Atlantic and Pacific species Macoma balth-ica ). We combined porewater pressure sensing, time-lapse photography and oxygen imaging to quantify the durations and frequencies of tellinid irrigation activity and the associated oxygen dynamics in the sediment. Porewater pressure records of all tellinids were dominated by intermittent porewater pressurization, induced by periodic water injection into the sediment through their excurrent siphons, which resulted in intermittent oxygen supply to subsurface sediments. The irrigation (two–12 minutes long)andintervalsbetweensubsequentirrigationbouts(1.5–13minutes)variedamongtellinidspecies andindividualsizes.Forlarge M. liliana and M. nasuta , the average intervals between irrigation bouts weresufficientlylong(10minutesandfourminutes,respectively)toallowcompleteoxygenconsump-tioninbetweenirrigationboutsinalltestedsedimenttypes.Irrigationpatternsofsmallerconspecifics andthesmallerspecies M. balthica were characterized by significantly shorter separation of irrigation bouts, which resulted in more continuous oxygenation of the sediment. Transport-reaction modeling confirmed these species-and size-specific geochemical signatures and indicated that the geochemical character of the sediment is largely conditioned by the interplay between temporal irrigation patterns and sedimentary oxygen consumption rates. For large tellinids, model simulations indicated that oscillatory rather than stationary geochemical conditions are prevalent in a wide range of sediment types, with oxic pockets collapsing completely between periods of active irrigation. Based on the model results we developed analytical approximations that allow estimation of spatio-temporal characteristics of sediment oxygenation for a wide range of sediment types and infaunal activity patterns. Our results emphasize the need to consider the intermittent nature of bioirrigation when studying the geochemical impact of infauna in permeable sediments.