摘要
The study proposes methodological developments to optimize sampling strategy of resting cysts of Alexandrium catenella to estimate their abundance with a predefined error. This work also aims to provide information on spatial distribution of resting cysts in sediments. The distribution mode of A. catenella resting cysts related to the abundance variability was studied through sediment cores sampling on four different spatial scales and using Ludox CLX gradient density method. The quantification method underestimates by a factor of 2 the resting cysts abundance in one gram of sediment. Application of Taylor's power law allowed us to define a compromise between sampling effort and abundance estimation error. In the case of A. catenella resting cysts from Thau lagoon, the optimal sampling strategy consists of sampling 10 stations on a surface of 2 km2 for a given coefficient of variability (C) of 15%, sampling 3 sediment cores at each station (C = 30%) and counting only one replicate by core (C = 18%). Results related to the application of Taylor's power law are closely dependent on resting cyst density and aggregation in a given sediment. In our area, A. catenella resting cysts are mainly observed in the upper 3 cm of sediment. Horizontally, their heterogeneity is lower on 10 cm2 surface and tends to stabilize itself beyond a surface of 10 m2. Each author has to carry out this pre-sampling effort for his own resting cysts-forming species, in his own area, in order to increase accuracy of resting cyst mapping.
摘要译文
该研究提出了方法学的发展，以优化亚历山大藻（Alexandrium catenella）静息囊肿的采样策略，以预定的误差估计其丰度。这项工作还旨在提供有关沉积物中静息囊肿空间分布的信息。 A的分配方式通过四种不同空间尺度的沉积物岩心取样并使用Ludox CLX梯度密度法研究了与丰度变化相关的Catenella静息囊肿。量化方法低估了1克沉积物中静息孢囊丰度的2倍。泰勒幂律的应用允许我们在采样努力和丰度估计误差之间定义折衷。在来自Thau泻湖的A. catenella休息囊肿的情况下，最佳采样策略包括在2 km sup 2 / sup的表面上对10个站点进行采样，给定的变异系数（C）为15％，每个站采样3个沉积物岩心（C \x3d 30％），核心仅重复一次重复（C \x3d 18％）。与泰勒幂律的应用相关的结果与给定沉积物中的静息囊肿密度和聚集密切相关。在我们的地区，A。Catenella静息囊肿主要在上部3 cm的沉积物中观察到。横向上，它们的异质性在10 cm sup 2 / sup表面较低，并且趋向于使其自身稳定在10 m sup 2 / sup的表面之外。每个作者都必须在他自己的区域为自己的静息囊肿形成物种进行这种预采样工作，以提高静息囊肿标测的准确性。
B.Genovesi[a];D.Mouillot[a];A.Vaquer[a];M.Laabir[a];A.Pastoureaud[b];. Towards an optimal sampling strategy for Alexandrium catenella (Dinophyceae) benthic resting cysts[J]. Harmful Algae, 2007,6(6): 837-848