Particulate amino acid and carbohydrates and particulate organic carbon and nitrogen in suspended and sinking organic matter from METEOR cruise M160@en

We collected in situ marine snow aggregates with a Marine Snow Catcher (MSC). The MSC allows studying the composition of suspended and fast-sinking organic matter from intact in situ formed aggregates (Riley et al. 2012). After deployment, the MSC was left vertically on deck for three hours, seawater containing suspended organic matter was collected from the top part of the MSC and fast-sinking organic matter was picked manually from the MSC base. The MSC was deployed within the mixed layer depth. Duplicate samples for particulate organic carbon (POC) and organic nitrogen (PON) were filtered onto pre-combusted (450 ◦C for 5 h) Whatman GF/F filters (25 mm, 0.7 µm) under low pressure (< 200 mbar). Filters were frozen at −20 °C and stored until analysis. Prior to analysis, filters were acid-fumed (37% HCl for 24 h) in order to remove inorganic carbon and dried at 40°C for 24 h. Subsequently, filters were wrapped in tin cups (8×8×15 mm), combusted and analyzed according to Sharp (1974) using an elemental analyzer (Euro EA). We determined high-molecular-weight (>1 kDa) particulate combined carbohydrates (pCCHO) based on Engel and Händel (2011) and particulate hydrolysable amino acids (pHAA) based on Lindroth and Mopper (1979) and Dittmar et al., (2009). The analysis of pCCHO detected 11 monomers: and the pHAA analysis classified 13 monomers. The calculations for the carbon and nitrogen contents of pCCHO and pHAA were based on carbon and nitrogen atoms contained in the identified monomers.本研究使用海洋雪采集器（Marine Snow Catcher, MSC）原位采集海洋雪聚集体。该采集器可针对原位形成的完整聚集体，探究悬浮态与快速沉降有机质的组成（Riley等，2012）。布放完成后，将采集器垂直放置于甲板静置3小时，从采集器上部收集含悬浮有机质的海水，并手动从采集器底部获取快速沉降有机质。本次布放作业位于混合层深度范围内。将颗粒有机碳（Particulate Organic Carbon, POC）与有机氮（Particulate Organic Nitrogen, PON）的平行样在低压（<200 mbar）条件下，过滤至预先灼烧（450℃，5小时）的Whatman GF/F滤膜（直径25 mm，孔径0.7 µm）上。将滤膜置于-20℃冷冻保存，直至后续分析。分析前，将滤膜置于37%盐酸中熏蒸24小时以去除无机碳，随后在40℃下烘干24小时。随后将滤膜封装至8×8×15 mm的锡杯中，参照Sharp（1974）的方法，使用元素分析仪（Euro EA）进行灼烧与分析。本研究参照Engel与Händel（2011）的方法测定了高分子量（>1 kDa）颗粒结合碳水化合物（pCCHO），并参照Lindroth与Mopper（1979）及Dittmar等（2009）的方法测定了颗粒水解氨基酸（pHAA）。pCCHO分析共检出11种单糖单体，pHAA分析则鉴定出13种氨基酸单体。pCCHO与pHAA的碳、氮含量计算基于已鉴定单体中所含的碳、氮原子数。