Investigating the carbon cycle in the Gulf of Maine using the natural tracer thorium 234
Investigating the carbon cycle in the Gulf of Maine using the natural tracer thorium 234
复制标题
DOI：
10.1029/1999jc000277
复制
发表时间：
2001-06
影响因子：
--
通讯作者：
M. Charette;S. B. Moran;S. Pike;John N. Smith
中科院分区：
文献类型：
--
作者：
M. Charette;S. B. Moran;S. Pike;John N. Smith
用天然放射性核素234(t1/2=24.1天)研究了缅因湾的有机碳循环。在缅因州中部的威尔金森和约旦盆地进行了季节性研究(1995年3月、6月和9月)，并在1997年8月至9月期间进行了区域调查，其中包括斯科特大陆架。颗粒有机碳(POC)出口(颗粒出口产生量)是根据234通量的三维稳态模型结合对>；53-μm颗粒的POC/234比值的测量来估计的。该区域的POC出口随季节变化；平均值在15至34mmolCm−2 d−1之间，占区域综合初级生产量的11%至25%。缅因湾是(大西洋中部海湾)溶解有机碳(2.4mmolCm−2 d−1)的净来源，占碳吸收速率的∼2%。沉积物中的有机碳埋藏量只占初级生产量的一小部分，平均为1.6mmolCm−2d−1。虽然只有一小部分出口产品埋藏在沉积物中，但这些估计值接近缅因湾有机碳的预算。这意味着，现货出口在这个货架地区可能不像之前估计的那样重要。
The naturally occurring radionuclide 234Th (t1/2 = 24.1 days) was used to examine the organic carbon cycle in the Gulf of Maine. A seasonal study (March, June, and September 1995) was conducted in the central Gulf of Maine in Wilkinson and Jordan Basins, and a regional survey, which included the Scotian Shelf, was conducted during August-September 1997. Particulate organic carbon (POC) export (particulate export production) was estimated from a three-dimensional steady state model of 234Th flux combined with measurements of the POC/234Th ratio on >53-μm particles. The POC export for this region was seasonally variable; average values ranged from 15 to 34 mmol C m−2 d−1, between 11% and 25% of the regionally integrated primary production. The Gulf of Maine was a net source (to the Mid-Atlantic Bight) of dissolved organic carbon (2.4 mmol C m−2 d−1) amounting to ∼2% of carbon uptake rates. Organic carbon burial in the sediments was a minor fraction of the primary production, averaging 1.6 mmol C m−2 d−1. Though only a fraction of total export production was buried in the sediments, these estimates close the budget for organic carbon in the Gulf of Maine. An implication is that off-shelf export may not be as important as previously estimated in this shelf region.