Effects of turbulence on TEP dynamics under contrasting nutrient conditions:: implications for aggregation and sedimentation processes
Effects of turbulence on TEP dynamics under contrasting nutrient conditions:: implications for aggregation and sedimentation processes
复制标题
DOI：
10.3354/meps323047
复制
发表时间：
2006-01-01
影响因子：
2.5
通讯作者：
Marrase, C.
中科院分区：
文献类型：
--
作者：
Beauvais, S.;Pedrotti, M. L.;Marrase, C.
在北海沿海自然水域中研究了不同小尺度湍流强度对透明外聚合物颗粒（TEP）动力学的影响。在添加和不添加营养物的中生态系统中检查 TEP 的丰度、体积、尺寸谱和碳含量：无添加（T 系列）和第一天的 Redfield 比例供应（NT 系列），施肥 16 mu M N: 1 mu M P:32 mu M Si，以有利于浮游植物以水华形式生产。湍流由垂直振荡网格产生，连续运行 14 d。我们确定了在对比营养条件下 TEP 产量是否随湍流水平而变化。 TEP 浓度随湍流增加。湍流的影响可能是间接的，它会导致主动分泌 TEP 前体的硅藻生长速度加快，特别是当营养物质耗尽时。 TEP 生产后，无论湍流水平如何，颗粒有机碳与氮的比率在水华后都会增加。 TEP 的形成导致碳和氮动力学的解耦，大量碳流进入 TEP 池，占初级产量的 44%，并且与湍流强度保持恒定。虽然湍流对小颗粒（<40μm）没有影响，但湍流有利于>40μm的TEP聚集。我们发现，当湍流较低时（5 至 8 x 10(-2) cm(2) s(-3)），TEP 会显着沉降，并且 TEP 池会持续存在于水箱中，而在较高的湍流强度水平下不会下沉，这是典型的风暴事件（ε = 1 cm(2) s(-3)）。
The effect of different small-scale turbulence intensities on transparent exopolymeric particle (TEP) dynamics was studied in natural North Sea coastal waters. The abundance, volume, size spectra and carbon content of TEP were examined in mesocosms with and without added nutrients: no addition (T series) and a Redfield ratio supply on Day 1 (NT series), fertilized with 16 mu M N: 1 mu M P:32 mu M Si to favor phytoplankton production in the form of a bloom. Turbulence was generated by vertically oscillating grids, operating continuously for 14 d. We determined whether TEP production, under contrasting nutrient conditions, changes with level of turbulence. TEP concentration increased with turbulence. The effect of turbulence was likely indirect, by inducing an increase in growth rates of diatoms that actively exude TEP precursor, particularly when nutrients were exhausted. Following TEP production, the ratio of particulate organic carbon to nitrogen increased after the bloom, regardless of turbulence level. TEP formation led to a decoupling of carbon and nitrogen dynamics, with a large flow of carbon channeled into the TEP pool, representing up to 44% of the primary production, and was constant with the turbulence intensity. While turbulence had no effect on small particles (< 40 mu m), turbulence favored the aggregation of TEP > 40 mu m. We found significant sedimentation of TEP when turbulence was lower (5 to 8 x 10(-2) cm(2) s(-3)) and a persistence of the TEP pool in the tanks without sinking at higher levels of turbulence intensity, typical of storm events (epsilon = 1 cm(2) s(-3)).