Sediment trap data from Lake Peters and Lake Schrader, Arctic National Wildlife Refuge, Alaska, 2015-2017

Throughout 2015-2017, sediment traps were deployed in Lakes Peters and Schrader to measure the rate of deposition and collect suspended sediments in the lakes. In 2015, three pairs of static (i.e., non-automated) traps with different aspect ratios (different collection-tube heights but same collection-tube diameters) were deployed from May-August at a central location of Lake Peters to determine the effect of these proportions on sediment collection efficiency. In May-August 2016, one static trap was deployed in Lake Peters, two sets in Lake Schrader, and one set in a small pond on the southwestern edge of Lake Schrader ("Schrader Pond"). The same traps were also deployed for a full year from August 2016-August 2017. These traps consisted of ordinary 2 Liter plastic bottles with the bottoms removed, a 50 milliliter centrifuge tube secured to its mouth, and inverted to funnel sediments into the tubes. Each trap comprised two or three replicate tubes/bottles deployed at different depths along an anchored mooring. In addition, an incrementing sediment trap was deployed from May 2016 through August 2017, collecting sediments in 23 bottles rotating over daily to weekly increments. The last sample of these 23 increments should be interpreted cautiously, as there is evidence that excess sediments sluffed off into the bottle upon trap retrieval. This trap design is described in the following study: Muzzi, R.W. and Eadie, B.J., 2002. The design and performance of a sequencing sediment trap for lake research. Marine Technology Society Journal, 36, 2–28. For all sediment samples, dry sediment mass, daily flux, and annual flux were calculated. For several static trap samples, grain size data (mean, SD, d50, d90, %sand, %silt, and %clay) were determined using a Coulter LS-320 following diatom removal. Organic matter content was determined using loss on ignition analysis.

2015年至2017年间，研究团队在彼得斯湖（Lake Peters）与施拉德湖（Lake Schrader）布设了沉积物捕集器（sediment traps），用于测定湖泊沉积物的沉积速率并采集悬浮沉积物。2015年5月至8月，研究人员在彼得斯湖中心区域布设了3对静态（即非自动化）捕集器，这些捕集器的收集管高度各异但管径一致，即具有不同的长径比，布设周期为5月至8月，以探究该结构比例对沉积物收集效率的影响。2016年5月至8月，研究人员在彼得斯湖布设1台静态捕集器，在施拉德湖布设2组静态捕集器，同时在施拉德湖西南侧边缘的小型池塘“施拉德池塘（Schrader Pond）”布设1组。此外，研究团队于2016年8月至2017年8月对上述捕集器进行了为期一整年的持续布设。本次使用的捕集器由普通2升塑料瓶改造而成：切除瓶底后，在瓶口固定50毫升离心管，将装置倒置以形成漏斗结构，使沉积物顺利落入离心管内。每套捕集装置包含2或3组重复的管瓶结构，通过锚定系泊系统布设在不同水深位置。除此之外，2016年5月至2017年8月期间还布设了一台增量式沉积物捕集器，该装置通过23个瓶子按每日至每周的周期轮换采集沉积物。由于有证据表明在回收捕集器时，过量沉积物会滑落至瓶中，因此对这23个周期采集的最后一份样本需谨慎解读。该捕集器的设计详见以下研究文献：Muzzi, R.W. 与 Eadie, B.J., 2002. 《用于湖泊研究的序列式沉积物捕集器的设计与性能》，《海洋技术学会期刊（Marine Technology Society Journal）》，第36卷，第2–28页。针对所有沉积物样品，研究人员计算了沉积物干重、日沉积通量与年沉积通量。针对多组静态捕集器样品，在去除硅藻后，采用库尔特LS-320（Coulter LS-320）粒度分析仪测定了粒度数据，包括平均值、标准差（SD）、d50、d90、砂粒占比、粉粒占比与黏粒占比。有机质含量则通过烧失量分析法进行测定。