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

最近开发的微结构仪器的观察表明，以前被描述为小尺度生物斑块的现象可能不是由于生物结构的随机波动，而可能是对持续的小尺度结构的采样不足观察。上层海洋中持续的低于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。这样的采样方案很可能低估了与亚1米结构相关的原位速率过程，以及生物和化学性质的丰度和分布模式。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，本项目的总体目标是通过对营养物质浓度、颗粒物、自养生产和异养过程的直接测量来评估这些1米以下特征对上层海洋营养动力学的贡献，并对海洋中薄生物层的发生、持久性和组成进行详细研究。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，持久性和擦除机制。我们将确定在长时间内欣快区浮游生物生物量薄层的分布和时间相干性，并使用生物光学和生物声学传感器以及通过单个薄层的离散采样来表征生物薄层的组成。我们还将评估持续小尺度特征内部和外部的自养和异养速率过程，并绘制连贯薄层的面积范围。我们还将量化薄层与局部物理过程的关联，特别是分层，小尺度剪切和湍流混合，以及大尺度速度场和内波的频率和振幅。最后，我们将研究薄层与当地地表强迫条件的关系，并评估层内发生的生物速率对总水柱过程的贡献。这个数据集将提供一个独特的机会，定量地评估持久性小尺度结构在海洋浮游生物食物网中的作用。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率估计将是有偏差的。+n±i * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *++++++++++++ + _ Ûª烧ÑOhª‘ +’ª█0 Ý + Õ $ H l +¢D H + R:\WWUSER\TEMPLATE\NORMAL。DOT =l James William Ammerman Joanne MCcreary @ =-vÞ█@ -+Y+ª)@ dP¹█}}@¶+ª微软Word 6.0 10Õª- e =- e P - P f f f f f ÷ 1z z z z 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 z z P 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