Abstract It has been historically documented that deep, nutrient-rich, offshore slope waters that enter the Gulf of Maine through the Northeast Channel are the principal source of nutrients to the region. Silicate (Si(OH)4) and nitrate (NO3) in particular are potentially limiting nutrients for phytoplankton production. We examine here the extent to which nutrient variability in the region may be caused by internal recycling of organic material (i.e., chemical breakdown and dissolution of diatoms) versus variability in water mass sources, which can be identified by temperature and salinity properties. We present here the results from a gulf-wide survey conducted in October 2016. Nutrient samples were collected at 44 stations and compared to temperature, salinity, and beam attenuation profiles. Additionally, suspended particulate material in near-bottom waters was collected on filters at all stations and analyzed for biogenic silica. The results show that after being supplied via a slope water source, nitrate is likely to become depleted and silicate is likely to become enriched at any location in the gulf. We suspect that most of the nutrient variability is due to internal recycling, but there is evidence for an input of Scotian Shelf Water to the Jordan Basin region contributing nutrients at mid-depths and mixing with the deeper slope waters.

中文翻译：

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源水团和内部循环对缅因湾溶解无机养分浓度的影响

摘要 历史记载，通过东北海峡进入缅因湾的深、营养丰富的近海斜坡水域是该地区营养的主要来源。硅酸盐 (Si(OH)4) 和硝酸盐 (NO3) 特别是可能限制浮游植物生产的营养物质。我们在这里检查了该地区养分变异的程度可能是由有机物质的内部循环（即硅藻的化学分解和溶解）引起的，而水体来源的变异可以通过温度和盐度特性来识别。我们在此展示了 2016 年 10 月进行的海湾范围调查的结果。在 44 个站点收集了营养样本，并与温度、盐度和光束衰减剖面进行了比较。此外，在所有站点的过滤器上收集了近底水中的悬浮颗粒物质，并分析了生物二氧化硅。结果表明，通过斜坡水源供应后，硝酸盐很可能会枯竭，而在海湾的任何位置，硅酸盐都可能会富集。我们怀疑大部分养分变异是由于内部循环造成的，但有证据表明，苏格兰大陆架水输入到约旦盆地地区，在中深度提供养分并与更深的斜坡水混合。