کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1242644 1645368 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Analytical performance during ratiometric long-term imaging of pH in bioturbated sediments
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Analytical performance during ratiometric long-term imaging of pH in bioturbated sediments
چکیده انگلیسی

In this study, the long-term analytical performance of a high-resolution ratiometric imaging sensor for pH was quantitatively determined. The sensor was applied in an experimental microcosm to illustrate biogeochemical consequences from mining activities by the chemosymbiotic bivalve Thyasira sarsi. Utilizing time-correlated pixel-by-pixel calibration protocols during imaging, close to 90% of the pixels were associated with a precision (S.D.) of <0.05 pH units at the end of an experimental period of 17 days. For comparison, a precision of <0.05 pH units was achieved for less than 50% of the pixels throughout experiments using conventional pre-sample calibration procedures. The average standard deviation of pixels was 0.01 pH units. Image analysis of single pixel derivatives and pH measurements over time suggested that T. sarsi affect pH distributions and general sediment geochemistry more than would be expected based on the small size of the bivalves. A significant decrease of pH in the overlying water suggested a considerable release of reduced compounds from the exhalent stream of the thyasirids. Strong pH gradients were demonstrated not only across the sediment–water interface but, also associated with bioturbation activities immediately adjacent to T. sarsi burrowing tracts, inhalant tubes and pedal tracts in the sediment matrix. Gradients of up to 1.16 pH units per mm were observed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Talanta - Volume 81, Issues 4–5, 15 June 2010, Pages 1393–1401
نویسندگان
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