An Evaluation of the Consequences of Persistent Small-Scale Biological Structure on Upper Ocean Trophic Processes

最近发展的微结构仪器的观察表明，以前被描述为小规模生物斑块的现象可能不是由于生物结构的随机波动造成的，而可能是对持续的小规模结构的欠采样观测。海洋上层持续的、低于1米的结构给精细尺度和中尺度观测项目的数据解释带来了严重的问题。这样的抽样方案很可能低估了与低于1米的结构相关的原位速率过程，以及生物和化学特性的丰度和分布模式。薄层的普遍存在和这些层的时空一致性迫使我们评估它们在上层海洋过程中的作用。因此，该项目的总体目标是通过直接测量营养物质浓度、颗粒物、自养生产和异养过程来评估这些小于1米的特征对上层海洋营养动态的贡献，并对海洋中薄生物层的出现、持续和组成进行详细的研究。此外，我们独特的高分辨率生物和物理采样系统将使我们能够研究层的形成、持久性和擦除的机制。我们将使用生物光学和生物声学传感器以及通过对单个薄层进行离散采样，确定在延长的时间段内浮游生物生物量薄层的分布和时间一致性，并表征生物薄层的组成。我们还将评估持续性小尺度地物内外的自养和异养速率过程，并绘制相关薄层的面积范围。我们还将量化薄层与局部物理过程的联系，特别是层结、小尺度切变和湍流混合，以及大尺度速度场和内波的频率和幅度。最后，我们将调查薄层与局部地表强迫条件的联系，并评估层内发生的生物速率对总水柱过程的贡献。这一数据集将提供一个独特的机会来定量评估持续的小尺度结构在海洋浮游食物网中的作用。如果没有对这些过程的明确评估，用传统抽样方法获得的生物比率的估计将是有偏见的。+n±i╝nüf S u m a r y in f r m a t i on n(+++_？？▓？？哦？+？？▒0？？$H L+，╗D？h+R：\WWUSER\TEMPLATE\NORMAL.DOT=L詹姆斯·威廉·安默曼乔安妮·麦克里里@=-v？▀@-+Y+？)@dp？▀}}@？+？Microsoft Word 6.0 10？e=-e P┐P fP f？1 z(==f T S；？z？z z？z zP X z z+z

Observations with recently developed microstructure instrumentation indicate that what had previously been described as small scale biological patchiness may not be due to stochastic fluctuations in biological structure, but may be undersampled observations of persistent, small scale structure. Persistent, sub 1-meter structure in the upper ocean poses serious problems for the interpretation of data from finescale and mesoscale observational programs. It is likely that such sampling programs are underestimating the in situ rate processes associated with sub 1-meter structure, as well as the abundance and distributional patterns of biological and chemical properties. The common occurrence of thin layers and the temporal/spatial coherence of these layers compel us to evaluate their role in upper ocean processes. Therefore, the overall objectives of this project are to evaluate the contribution of these sub-1-meter features to upper ocean trophic dynamics through direct measurements of nutrient concentration, particulate matter, autotrophic production, and heterotrophic processes, and to undertake a detailed study of the occurrence, persistence, and composition of thin biological layers in the ocean. In addition, our unique high resolution biological and physical sampling system will permit us to investigate the mechanisms of layer formation, persistence and erasure. We will determine the distribution and temporal coherence of thin layers of plankton biomass within the euphoric zone over extended time periods and characterize the composition of biological thin layers using bio optical and bio acoustical sensors as well as via discrete sampling of individual thin layers. We will also assess autotrophic and heterotrophic rate processes inside and outside of persistent small scale features and map the areal extent of coherent thin layers. We will also quantify the association of thin layers with local physical processes, specifically stratification, small scale shear, and turbulent mixing, as well as the large scale velocity field and the frequency and amplitude of internal waves. Finally, we will investigate the association of thin layers with local surface forcing conditions and evaluate the contribution of biological rates occurring within layers to total water column processes. This data set will provide a unique opportunity to evaluate, quantitatively, the role of persistent small scale structure in oceanic planktonic food webs. Without a clear evaluation of these processes, estimates of biological rates obtained with conventional sampling approaches will be biased. +n ±i ╝n ¼f S u m m a r y I n f o r m a t i o n ( ++++++++++++ 8 Û ++++++++++++ ++++++++++++ ++++++++++++ + _ Ûª▓ ÑOh ª' +'ª▒0 Ý + Õ $ H l + ¢ ╗ D h + R:\WWUSER\TEMPLATE\NORMAL.DOT =l James William Ammerman Joanne MCcreary @ =-vÞ ▀ @ -+Y+ª) @ dP¹ ▀ } } @ ¶+ª Microsoft Word 6.0 10 Õªe =- e P ┐ P f f f f f f p f ÷ 1 z z z z z z z z ( = = f T s ; ÷ z z z z z ÷ z z z z z z z z z P X z z + z