Sampling sandy surface sediments is an important first step in understanding biogeochemical processes in these dynamic environments. However, sampling such sediments poses several challenges, especially when undisturbed samples with porewater are required. Several grab samplers are commercially available, but they are either prone to sample loss, too heavy or bulky for use in small vessels, or those with spring-loaded mechanisms present safety issues. Here, we present the Ellrott grab, a lightweight sediment sampler designed for collecting undisturbed surface sediments including porewater and overlying bottom seawater. The sampler consists of a frame and a rotating bowl that can collect 370 cm² of surface sediments up to 10 cm deep (2.5 liters total volume). The instrument is 40 × 60 cm in size, has a basic weight of 10 kg, with up to 20 kg additional weights for stability in sandy sediments. Two persons can operate the grab and it can be used on small boats with a crane and winch system or a hand winch. The grab is now in routine use in the Wadden Sea and in Isfjorden, Svalbard. The samples obtained from the grab were suitable for various geochemical and microbial analyses. Using microelectrodes, we found that in situ oxygen profiles were similar to ex situ profiles in cores subsampled from the grab, confirming that the grab causes minimal disturbance to the sample. Although the grab was designed for collecting sandy sediments, it could also be applied to silty sediments, allowing straightforward and efficient sampling of various sediment types.

中文翻译：

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Ellrott 抓斗：一种小型、轻型沉积物采样器，用于收集未受干扰的沙质沉积物

对沙质表面沉积物进行采样是了解这些动态环境中生物地球化学过程的重要第一步。然而，对此类沉积物进行采样面临着一些挑战，特别是当需要含有孔隙水的未受干扰样品时。市面上有几种抓取取样器，但它们要么容易丢失样品，要么太重或体积太大，不适合在小型容器中使用，要么带有弹簧加载机构的取样器存在安全问题。在这里，我们展示了 Ellrott 抓取器，这是一种轻型沉积物采样器，设计用于收集未受干扰的表面沉积物，包括孔隙水和上覆底部海水。采样器由框架和旋转碗组成，可收集 370 cm ²的表面沉积物，深达 10 cm（总体积 2.5 升）。该仪器尺寸为 40 × 60 厘米，基本重量为 10 公斤，为了在沙质沉积物中保持稳定性，可增加最多 20 公斤的附加重量。抓斗可由两人操作，可在带有起重机和绞盘系统或手动绞盘的小船上使用。该抓斗现已在瓦登海和斯瓦尔巴群岛伊斯峡湾常规使用。从抓取中获得的样品适用于各种地球化学和微生物分析。使用微电极，我们发现原位氧分布与从抓取物中二次取样的岩心的异位分布相似，证实抓取物对样品造成的干扰最小。尽管该抓斗设计用于收集沙质沉积物，但它也可以应用于粉质沉积物，从而可以对各种沉积物类型进行简单有效的采样。