DMS emissions from the Arctic marginal ice zone
DMS emissions from the Arctic marginal ice zone
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DOI：
10.1525/elementa.2020.00113
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发表时间：
2021-07-14
影响因子：
3.9
通讯作者：
Levasseur, Maurice
中科院分区：
文献类型：
--
作者：
Gali, Marti;Lizotte, Martine;Levasseur, Maurice
北极边缘冰区（MIZ）的浮游植物大量繁殖，可以大量产生二甲硫醚（DMS），从而影响区域气溶胶的形成和云辐射强迫。在这里，我们描述了 2016 年初夏，DMS 及其前体二甲磺基丙酸 (DMSP) 在巴芬湾消退的冰缘上的分布。总体而言，DMS 和总 DMSP (DMSPt) 向大西洋起源的较温暖水域增加，同时冰融化和水华阶段也更先进。在表层（0-9 m 深度）观察到相对较高的 DMS 和 DMSPt（中值分别为 6.3 和 70 nM），在地下生物量最大值（15-30 m 深度）处观察到非常高的值（分别达到 74 和 524 nM）。显微镜和色素分析表明，地下 DMS 和 DMSPt 峰与普氏棕囊藻 (Phaeocystis pouchetii) 有关，这种藻类在受大西洋影响的水域中大量繁殖，并在巴芬湾达到了前所未有的生物量水平。在地表水中，MIZ 中的 DMS 浓度和 DMS:DMSPt 比率（中位数分别为 12 nM 和 0.15）比完全冰覆盖或无冰条件下更高，这可能与浮游植物 DMSP 释放和细菌 DMSP 裂解增强（高 dddP: dmdA 基因比率）有关。由于近地表 DMS 浓度和气体交换的物理驱动因素的并发趋势，平均海空气 DMS 通量（mmol m(-2) d(-1)）从冰覆盖水域的 0.3 增加到开放水域的 10（最大值 26）。利用遥感海冰覆盖范围和海气DMS通量数据的汇编，我们估计MIZ（E-DMS，E-MIZ）的泛北极DMS排放量为5-13 Gg S yr(-1)。在北纬 80 度以北，2003 年至 2014 年间，E-DMS、E-MIZ 可能每年增加约 10 +/- 4%(-1)，可能超过 6 月和 7 月的开放水域排放量。我们的结论是，在评估北极浮游生物气候反馈时必须考虑 E-DMS、E-MIZ。
Phytoplankton blooms in the Arctic marginal ice zone (MIZ) can be prolific dimethylsulfide (DMS) producers, thereby influencing regional aerosol formation and cloud radiative forcing. Here we describe the distribution of DMS and its precursor dimethylsulfoniopropionate (DMSP) across the Baffin Bay receding ice edge in early summer 2016. Overall, DMS and total DMSP (DMSPt) increased towards warmer waters of Atlantic origin concurrently with more advanced ice-melt and bloom stages. Relatively high DMS and DMSPt (medians of 6.3 and 70 nM, respectively) were observed in the surface layer (0-9 m depth), and very high values (reaching 74 and 524 nM, respectively) at the subsurface biomass maximum (15-30 m depth). Microscopic and pigment analyses indicated that subsurface DMS and DMSPt peaks were associated with Phaeocystis pouchetii, which bloomed in Atlantic-influenced waters and reached unprecedented biomass levels in Baffin Bay. In surface waters, DMS concentrations and DMS:DMSPt ratios were higher in the MIZ (medians of 12 nM and 0.15, respectively) than in fully ice-covered or ice-free conditions, potentially associated with enhanced phytoplanktonic DMSP release and bacterial DMSP cleavage (high dddP: dmdA gene ratios). Mean sea-air DMS fluxes (mmol m(-2) d(-1)) increased from 0.3 in ice-covered waters to 10 in open waters (maximum of 26) owing to concurrent trends in near-surface DMS concentrations and physical drivers of gas exchange. Using remotely sensed sea-ice coverage and a compilation of sea-air DMS flux data, we estimated that the pan-Arctic DMS emission from the MIZ (E-DMS,E- MIZ) was 5-13 Gg S yr(-1). North of 80 degrees N, E-DMS,E- MIZ might have increased by around 10 +/- 4% yr(-1) between 2003 and 2014, likely exceeding open-water emissions in June and July. We conclude that E-DMS,E- MIZ must be taken into account to evaluate plankton-climate feedbacks in the Arctic.