A comparison of sediment reworking rates by. the surface deposit-feeding bivalve Abra ovata during summertime and wintertime, with a comparison between two models of sediment reworking
A comparison of sediment reworking rates by. the surface deposit-feeding bivalve Abra ovata during summertime and wintertime, with a comparison between two models of sediment reworking
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DOI：
10.1016/j.jembe.2006.10.052
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发表时间：
2007-04-30
影响因子：
2
通讯作者：
Meysman, F. J. R.
中科院分区：
文献类型：
--
作者：
Maire, O.;Duchene, J. C.;Meysman, F. J. R.
利用发光团示踪粒子的自动图像分析程序，在薄水族箱中评估了表面沉积物捕食双壳贝Abra ovata对沉积物的改造率。试验在冬季（10℃）和夏季（20℃）进行，分为不添加食物（CF）、低添加食物(U)和高添加食物（HF） 3种食物处理。沉积物的再加工速率以四种不同的方式表征：(1)发光团的最大穿透深度（MPD），(2)再加工沉积物表面的比例（PRS），由此推导出单个表面积再加工速率（IRSAR），(3)标准生物扩散模型的拟合导致生物扩散系数D-b，以及(4)应用新的非局部生物扰动模型产生替代混合强度D-b。在冬季，沉积物的再加工较少，不受食物供应的影响。相反，在夏季，返工活动非常高，并受到食物供应的显著影响。这表明，在冬季，控制沉积物再加工的是温度，而不是食物供应。尽管生物扩散模型和非局部模型在48 h后产生的混合强度值相似，但非局部模型在实验初始阶段的拟合效果明显更好。这与理论预测很好地吻合：在短时间尺度上，非局部模型应该提供更准确的生物扰动描述，但随着生物扰动事件数量的增加，非局部模型应该收敛于生物扩散模型。然而，非局部模型的另一个优点是，它允许约束表征A. ovata生物扰动的两个关键参数：粒子位移的平均距离（2.1 mm）和两个生物扰动事件之间的等待时间（5.39 h）。因此，重加工的特点是高频率和小尺度的颗粒位移，这使得a . ovata可以归类为真正的生物扩散者。(c) 2007 Elsevier B.V.版权所有
Sediment reworking rates by the surface deposit-feeding bivalve Abra ovata were assessed in thin aquaria using an automated image analysis procedure for luminophore tracer particles. Experiments were carried in winter (10 degrees C) and summer (20 degrees C), and three food treatments were tested: no food addition (CF), low food addition (U) and high food addition (HF). The rate of sediment reworking was characterized in four different ways: (1) the maximum penetration depth of luminophores (MPD), (2) the proportion of reworked sediment surface (PRS) from which individual rates of surface area reworking (IRSAR) were derived, (3) the fitting of the standard biodiffusion model resulting in a biodiffiision coefficient D-b, and (4) the application of a new non-local bioturbation model that produced an alternative mixing intensity D-b. In winter, sediment reworking was low and was not affected by food availability. In contrast, during summer, reworking activity was very high and significantly affected by food availability. This suggests that temperature and not food availability controls sediment reworking during wintertime. Although the biodiffusive and non-local models produced similar values for mixing intensities after 48 h, the non-local model gave markedly better fits during the initial stage of the experiment. This agrees nicely with theoretical predictions: over short-time scales the non-local model should provide a more accurate description of bioturbation, but as the number of bioturbation events increases, the non-local model should converge to the biodiffusion one. Yet, an additional advantage of the non-local model is that it allows constraining two crucial parameters characterizing A. ovata bioturbation: the average distance over which particles are displaced (2.1 mm) and the waiting time between two bioturbation events (5.39 h). Accordingly, reworking is characterized by highly frequent and small-scale particle displacement, which makes that A. ovata can be classified as a true biodiffuser. (c) 2007 Elsevier B.V. All rights reserved.