Fecal Pellet production by copepods during UPSB

To quantify grazing impact of copepod to UPSB in the wouthwester Baffin Bay, we conducted fecal pellet production experiments. Experimental specimens (i.e. copepods) were collected at 1 x 1 m hole on the first-year landfast ice once for each 2-7 days between 24 May to 7 July 2016 as a part of the Green Edge 2016 field campaign. A 200 micrometer mesh, 0.785 m2 mouth aperture conical net equipped with a rigid live-capture cod-end was hauled vertically from 100 m (from 24 May to 21 June) or 30 m (from 25 June to 10 July) to the surface at towing speed of 0.3 m s-1. To remove the effects of variation in the volume filtered due to the difference of net towing depth (30 m or 100 m), fecal pellets production rate was standardized for those data as towing distance of 100 m (i.e., the production rate per square meter = Raw data x100 / towing depth). Collected specimens were incubated in filtered sea water to collect fecal pellets. Those produced fecal pellets were counted and meausred width, length and shape under a stereo-microscope in a laboratory.为量化巴芬湾西南海域桡足类（copepod）对UPSB的牧食影响，本研究开展了粪便颗粒生产实验。作为Green Edge 2016野外科考项目的组成部分，我们于2016年5月24日至7月7日期间，每隔2至7天在当年形成的固定海冰的1米×1米冰孔处采集实验用桡足类样本。实验采用孔径200 μm、网口面积0.785 m²的锥形拖网，搭配刚性活体捕获型拖网囊，以0.3 m·s⁻¹的速度从水深100 m（2016年5月24日至6月21日）或30 m（2016年6月25日至7月10日）垂直拖曳至海面进行采样。为消除拖网深度差异导致的过滤体积变化对实验结果的影响，我们将所有粪粒生产速率标准化为拖曳距离100 m的情况，计算公式为：单位面积生产速率 = 原始数据 ×100 / 拖曳深度。采集得到的桡足类样本被置于过滤海水中进行培养，以收集其产生的粪便颗粒。随后在实验室中通过体视显微镜对产出的粪便颗粒进行计数，并测量其宽度、长度及形态特征。