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

持续性小规模生物结构对上层海洋营养过程影响的评估

• 批准号: 9618137
• 负责人: Timothy Cowles
• 金额: $ 31.43万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-15 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9618137&HistoricalAwards=false
• 关键词: Evaluation; Consequences; Persistent; Small; Scale

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

最近开发的微结构仪器的观察表明，以前被描述为小规模的生物斑块可能不是由于生物结构的随机波动，但可能是持续的，小规模的结构欠采样观察。海洋上层持续存在的低于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。这种取样方案可能低估了与1米以下结构有关的原地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间/空间一致性迫使我们评估其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浓度、颗粒物、自养生产和异养过程，评估这些低于1米的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形成，持久性和擦除的机制。 我们将确定在较长的时间内欣快区浮游生物量的薄层的分布和时间一致性，并使用生物光学和生物声学传感器以及通过离散采样的个别薄层的生物薄层的组成特征。 我们还将评估自养和异养率过程内部和外部的持久性小规模的功能和映射的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，我们将调查与当地表面强迫条件的薄层的关联，并评估层内发生的生物速率对总水柱过程的贡献。 该数据集将提供一个独特的机会来定量评估海洋浮游食物网中持久性小规模结构的作用。如果不对这些过程进行明确的评价，用传统的取样方法获得的生物速率估计值将是有偏差的。 +n ±i n <$f S um m m ary in for m m a t i o n ( ++++++++++++ 8 Û ++++++++++++ ++++++++++++ ++++++++++++ + _ 你好，我的天啊 Ý + Õ $ H L + ¢ ╗ D H + R:\WWUSER\TEMPLATE\NORMAL.DOT =L 詹姆斯·威廉·安默曼 乔安妮·麦克里 @ =-vanadium @ -+Y+ A） @ dP单位 } } @ ¶+ª Microsoft Word 6.0 10 e =- e P ┐ P F F F F F F p F ÷ 1 z z z z z z z z ( = = F 不 S ; ÷ z z z z z ÷ z z z z z z z z z P X z z + z