Using Lagrangian sampling to study water quality during downstream transport in the San Luis Drain, California, USA

Chemical Geology
By: , and 

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Abstract

To investigate the mechanism for diel (24h) changes commonly observed at fixed sampling locations and how these diel changes relate to downstream transport in hypereutrophic surface waters, we studied a parcel of agricultural drainage water as it traveled for 84h in a concrete-lined channel having no additional water inputs or outputs. Algal fluorescence, dissolved oxygen, temperature, pH, conductivity, and turbidity were measured every 30min. Grab samples were collected every 2h for water quality analyses, including nutrients, suspended sediment, and chlorophyll/pheophytin. Strong diel patterns were observed for dissolved oxygen, pH, and temperature within the parcel of water. In contrast, algal pigments and nitrate did not exhibit diel patterns within the parcel of water, but did exhibit strong diel patterns for samples collected at a fixed sampling location. The diel patterns observed at fixed sampling locations for these constituents can be attributed to algal growth during the day and downstream transport (washout) of algae at night. Algal pigments showed a rapid daytime increase during the first 48h followed by a general decrease for the remainder of the study, possibly due to sedimentation and photobleaching. Algal growth (primarily diatoms) was apparent each day during the study, as measured by increasing dissolved oxygen concentrations, despite low phosphate concentrations (<0.01mgL-1). ?? 2011 Elsevier B.V.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Using Lagrangian sampling to study water quality during downstream transport in the San Luis Drain, California, USA
Series title Chemical Geology
DOI 10.1016/j.chemgeo.2011.01.029
Volume 283
Issue 1-2
Year Published 2011
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Chemical Geology
First page 68
Last page 77