Benthic primary production and mineralization in a High Arctic fjord: in situ assessments by aquatic eddy covariance
Benthic primary production and mineralization in a High Arctic fjord: in situ assessments by aquatic eddy covariance
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DOI：
10.3354/meps11780
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发表时间：
2016-07-28
影响因子：
2.5
通讯作者：
Glud, Ronnie N.
中科院分区：
文献类型：
--
作者：
Attard, Karl M.;Hancke, Kasper;Glud, Ronnie N.
沿海和大陆架系统可能对北冰洋的运作产生重大影响，但关键的生态系统过程仍难以量化。我们采用水生涡度协方差（AEC）氧（O₂）通量法来估算格陵兰高北极峡湾的底栖初级生产和矿化作用。在40米深的透光层内，海床总初级生产量（GPP）在10米处最高（29毫摩尔O₂每平方米每天），在40米处降至5毫摩尔O₂每平方米每天，而夜间群落呼吸（CR）范围为11到25毫摩尔O₂每平方米每天。在80米处，CR降至约2.5毫摩尔O₂每平方米每天，并随着深度增加保持恒定。在深度≥80米处，动物活动约占CR的50%。当按比例换算到峡湾外40米区域时，底栖GPP和CR相当，底栖GPP是浮游生物生产量的26%。在该区域（5.7吨碳每天），CR比GPP高两倍，因此是净异养的。通过使用模拟的海床光照数据将由AEC得出的北极底栖GPP换算到整个北冰洋，我们估算出北冰洋底栖生物的年GPP为11.5×10⁷吨碳每年。平均而言，这个数值占北冰洋浮游植物年净生产量估算值的26%。因此，这个很少被考虑的组成部分对当代和未来北极生态系统的运作可能具有重要意义。
Coastal and shelf systems likely exert major influence on Arctic Ocean functioning, yet key ecosystem processes remain poorly quantified. We employed the aquatic eddy covariance (AEC) oxygen (O-2) flux method to estimate benthic primary production and mineralization in a High Arctic Greenland fjord. Seabed gross primary production (GPP) within the 40 m deep photic zone was highest at 10 m (29 mmol O-2 m(-2) d(-1)) and decreased to 5 mmol O-2 m(-2) d(-1) at 40 m, while nighttime community respiration (CR) ranged from 11 to 25 mmol O-2 m(-2) d-1. CR decreased to similar to 2.5 mmol O-2 m(-2) d(-1) at 80 m and remained constant with further depth. Fauna activity accounted for similar to 50% of the CR at depths = 80 m. Benthic GPP and CR were comparable when scaled to the outer fjord area 40 m, benthic GPP was 26% of the pelagic production. CR was 2-fold higher than GPP over this region (5.7 t C d(-1)) and thus net heterotrophic. By scaling AEC-derived Arctic benthic GPP to the entire Arctic Ocean using modelled seabed light data, we estimate an annual Arctic Ocean benthic GPP of 11.5 x 10(7) t C yr(-1). On average, this value represents 26% of the Arctic Ocean annual net phytoplankton production estimates. This scarcely considered component is thus potentially important for contemporary and future Arctic ecosystem functioning.