کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6322138 1619724 2016 16 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Spatiotemporal variations in the abundance and composition of bulk and chromophoric dissolved organic matter in seasonally hypoxia-influenced Green Bay, Lake Michigan, USA
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Spatiotemporal variations in the abundance and composition of bulk and chromophoric dissolved organic matter in seasonally hypoxia-influenced Green Bay, Lake Michigan, USA
چکیده انگلیسی


- Terrestrial DOM dominated in Green Bay, with increasing aquagenic DOM in late summer.
- Non-chromophoric DOC comprised 32% of the bulk DOC in June and 47% in August.
- Bulk DOM had a quasi-conservative mixing behavior but underwent compositional changes.
- EEM-PARAFAC analysis identified 1 protein-like and 3 humic-like DOM components.
- DOM was related to hypoxic condition in southern Green Bay during late summer.

Green Bay, Lake Michigan, USA, is the largest freshwater estuary in the Laurentian Great Lakes and receives disproportional terrestrial inputs as a result of a high watershed to bay surface area ratio. While seasonal hypoxia and the formation of “dead zones” in Green Bay have received increasing attention, there are no systematic studies on the dynamics of dissolved organic matter (DOM) and its linkage to the development of hypoxia. During summer 2014, bulk dissolved organic carbon (DOC) analysis, UV-vis spectroscopy, and fluorescence excitation-emission matrices (EEMs) coupled with PARAFAC analysis were used to quantify the abundance, composition and source of DOM and their spatiotemporal variations in Green Bay, Lake Michigan. Concentrations of DOC ranged from 202 to 571 μM-C (average = 361 ± 73 μM-C) in June and from 279 to 610 μM-C (average = 349 ± 64 μM-C) in August. In both months, absorption coefficient at 254 nm (a254) was strongly correlated to bulk DOC and was most abundant in the Fox River, attesting a dominant terrestrial input. Non-chromophoric DOC comprised, on average, ~ 32% of bulk DOC in June with higher terrestrial DOM and ~ 47% in August with higher aquagenic DOM, indicating that autochthonous and more degraded DOM is of lower optical activity. PARAFAC modeling on EEM data resulted in four major fluorescent DOM components, including two terrestrial humic-like, one aquagenic humic-like, and one protein-like component. Variations in the abundance of DOM components further supported changes in DOM sources. Mixing behavior of DOM components also indicated that while bulk DOM behaved quasi-conservatively, significant compositional changes occurred during transport from the Fox River to the open bay.

Dynamics of dissolved organic matter in Green Bay, Lake Michigan, USA.124

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Science of The Total Environment - Volume 565, 15 September 2016, Pages 742-757
نویسندگان
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