Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039;
Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039.
Proc Natl Acad Sci U S A. 2018 Nov 27;115(48):12235-12240. doi: 10.1073/pnas.1814559115. Epub 2018 Nov 14.
Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events (≥mean + 2 σ), and 43% from 2011 to 2017. From 2011 to 2017, when high-resolution SCOC data were available, time lags between changes in satellite-estimated export flux (EF), POC flux, and SCOC on the sea floor varied between six flux events from 0 to 70 days, suggesting variable remineralization rates and/or particle sinking speeds. Half of POC flux pulse events correlated with prior increases in EF and/or subsequent SCOC increases. Peaks in EF overlying Station M frequently translated to changes in POC flux at abyssal depths. A power-law model (Martin curve) was used to estimate abyssal fluxes from EF and midwater temperature variation. While the background POC flux at 3,400-m depth was described well by the model, the episodic events were significantly underestimated by ∼80% and total flux by almost 50%. Quantifying episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of POC sequestration and understanding the global carbon cycle.
越来越多的证据表明，大量在地表水中产生的颗粒有机碳（POC）在爆发性通量事件中，于数天内到达深海深渊。利用 29 年的现场观测记录，研究了位于东北太平洋（4000 米水深）的 M 站 POC 通量和沉积物群落耗氧量（SCOC）的爆发性峰值。1989 年至 2017 年，在 3400 米深处，高达 19%的 POC 通量出现在高强度爆发性事件（≥平均值+2σ）中，而在 2011 年至 2017 年期间，这一比例达到了 43%。在 2011 年至 2017 年期间，当获得高分辨率 SCOC 数据时，卫星估计的外逸通量（EF）、POC 通量和海底 SCOC 变化之间的时间滞后在 6 个通量事件中从 0 到 70 天不等，这表明再矿化速率和/或颗粒下沉速度存在差异。POC 通量脉冲事件中有一半与 EF 和/或随后的 SCOC 增加有关。M 站上方 EF 的峰值经常转化为深海处 POC 通量的变化。使用幂律模型（Martin 曲线），根据 EF 和中层水温度变化来估算深海通量。虽然该模型能够很好地描述 3400 米深处的背景 POC 通量，但对爆发性事件的估算却低估了约 80%，总通量则低估了近 50%。定量描述有机碳进入深海的爆发性脉冲，对于模拟 POC 埋藏的深度和强度以及理解全球碳循环至关重要。
