Several attempts have been made to find universal zonation schemes for the benthic fauna in sandy beaches. Usually, the nature and number of zones are not fixed and depend on the beach type and temporal changes in environmental characteristics. We characterized spatial and temporal variations in the structure of macrobenthic communities on an Amazonian macrotidal sandy beach (Farol Beach, Algodoal-Maiandeua Island, Brazil). Samples (macrobenthos and sediments) were collected during the rainy (March 2012 and 2013) and dry seasons (September 2011 and 2012) at six equidistant sites (50 m apart) from the high tide water mark to the swash zone. The physical gradients influenced the faunal distribution, with significant seasonal variations. Density and diversity increased seaward, while increasing moisture, organic matter content, and fine grains in sediments. Two faunal zonation schemes were observed. In the dry season, three faunal zones were distinguished: upper-intertidal, mid-intertidal, and low-intertidal, whereas in the rainy season, only two faunal zones were distinguished: upper-intertidal and low-intertidal. In the rainy season, the physical gradients along the intertidal appeared to be smooth, allowing the expansion of the upper-tidal zone. This study provides novel insights into macrobenthic distribution patterns, reinforcing that tropical macrotidal beaches have unique characteristics that strongly influence macrobenthic distribution patterns.

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亚马逊海岸（巴西）河口大潮沙滩上大型底栖动物群的时空分布模式

为寻找沙滩底栖动物群的通用分区方案已经进行了多次尝试。通常，区域的性质和数量不是固定的，取决于海滩类型和环境特征的时间变化。我们描述了亚马逊大潮汐沙滩（巴西 Algodoal-Maiandeua 岛的 Farol 海滩）上大型底栖动物群落结构的时空变化。在雨季（2012 年 3 月和 2013 年 3 月和 2013 年）和旱季（2011 年 9 月和 2012 年 9 月）期间，在从高潮水位到冲刷区的六个等距地点（相距 50 m）收集样品（大型底栖动物和沉积物）。物理梯度影响动物群分布，具有显着的季节性变化。向海的密度和多样性增加，同时增加水分、有机物含量，和沉积物中的细颗粒。观察到两种动物区划方案。在旱季，可区分出三个动物区系：上潮间带、中潮间带和低潮间带；而在雨季，仅可区分出两个动物区系：上潮间带和低潮间带。在雨季，沿潮间带的物理梯度显得平滑，允许上潮带扩张。这项研究提供了对大型底栖动物分布模式的新见解，强化了热带大型潮汐海滩具有强烈影响大型底栖动物分布模式的独特特征。只区分了两个动物区系：上潮间带和下潮间带。在雨季，沿潮间带的物理梯度显得平滑，允许上潮带扩张。这项研究提供了对大型底栖动物分布模式的新见解，强化了热带大型潮汐海滩具有强烈影响大型底栖动物分布模式的独特特征。只区分了两个动物区系：上潮间带和下潮间带。在雨季，沿潮间带的物理梯度显得平滑，允许上潮带扩张。这项研究提供了对大型底栖动物分布模式的新见解，强化了热带大型潮汐海滩具有强烈影响大型底栖动物分布模式的独特特征。