کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9758334 | 1496742 | 2005 | 27 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Phosphorus distribution in sinking oceanic particulate matter
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Despite the recognition of the importance of phosphorus (P) in regulating marine productivity in some modern oceanic systems and over long timescales, the nature of particulate P within the ocean is not well understood. We analyzed P concentration in particulate matter from sediment traps and selected core tops from a wide range of oceanic regimes: open ocean environments (Equatorial Pacific, North Central Pacific), polar environments (Ross Sea, Palmer Deep), and coastal environments (Northern California Coast, Monterey Bay, Point Conception). These sites represent a range of productivity levels, temporal (seasonal to annual) distributions, and trap depths (200-4400 m). P associations were identified using an operationally defined sequential extraction procedure. We found that P in the sediment traps is typically composed of reactive P components including acid-insoluble organic P (â¼Â 40%), authigenic P (â¼Â 25%), and oxide associated and/or labile P (â¼Â 21%), with lesser proportions of non-reactive detrital P depending on location (â¼Â 13%). The concentrations and fluxes of all particulate P components except detrital P decrease or remain constant with depth between the shallowest and the deepest sediment traps, indicating some regeneration of reactive P components. Transformation from more labile forms of P to authigenic P is evident between the deepest traps and core top sediments. Although for most sites the magnitudes of reactive P fluxes are seasonally variable and productivity dependent, the fractional associations of reactive P are independent of season. We conclude that P is transported from the upper water column to the sediments in various forms previously considered unimportant. Thus, acid-insoluble organic P measurements (typically reported as particulate organic P) likely underestimate biologically related particulate P, because they do not include the labile, oxide-associated, or authigenic P fractions that often are or recently were biologically related. Organic C to reactive P ratios are typically higher than Redfield Ratio and are relatively constant with depth below â¼Â 300 m suggesting that preferential regeneration of P relative to C occurs predominantly at shallow depths in the water column, but not deeper in the water column (> 300 m). The view of P cycling in the oceans should be revised (1) to include P fractions other than acid-soluble organic P as important carriers of reactive P in rapidly sinking particles, (2) to include the efficient transformation of labile forms of P to authigenic P in the water column as well as in sediments, and (3) to consider the occurrence of preferential P regeneration at very shallow depths.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Chemistry - Volume 97, Issues 3â4, 20 December 2005, Pages 307-333
Journal: Marine Chemistry - Volume 97, Issues 3â4, 20 December 2005, Pages 307-333
نویسندگان
Kristina L. Faul, Adina Paytan, Margaret L. Delaney,