Title

Soil Property Control of Biogeochemical Processes beneath Two Subtropical Stormwater Infiltration Basins

Authors

Authors

A. M. O'Reilly; M. P. Wanielista; N. B. Chang; W. G. Harris;Z. M. Xuan

Comments

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Abbreviated Journal Title

J. Environ. Qual.

Keywords

LARGE KARSTIC SPRINGS; NITRATE CONTAMINATION; NUTRIENT REMOVAL; WATER-CONTENT; FRESH-WATER; NITROGEN; DENITRIFICATION; GROUNDWATER; FLORIDA; BIORETENTION; Environmental Sciences

Abstract

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L-1 and decreases in nitrate nitrogen (NO3--N) from 2.7 mg L-1 to <0.016 mg L-1, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0-7.8 mg L-1), resulting in NO3--N of 1.3 to 3.3 mg L-1 in shallow groundwater. Enrichment of delta N-15 and delta O-18 of NO3- combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO3- transport beneath the sandy basin. Soil-extractable NO3--N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine-and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO3- impacts.

Journal Title

Journal of Environmental Quality

Volume

41

Issue/Number

2

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

564

Last Page

581

WOS Identifier

WOS:000300851200029

ISSN

0047-2425

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