Denitrification and Oxygen Consumption in Sediments of Two South Texas Estuaries

Author(s)

Won Bae Yoon, University of Texas at Austin
Ronald Benner, University of South Carolina - ColumbiaFollow

ORCID iD

Ronald Benner: https://orcid.org/0000-0002-1238-2777

Document Type

Article

Subject Area(s)

Biology

Abstract

Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N₂ m^-2 h^-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N₂ m^-2 h^-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O₂ m^-2 h^-1 in Nueces Estuary and from 208 to 550 µmol O₂ m^-2 h^-1 in Guadalupe Estuary. In both estuaries denitrification and oxygen consumption rates were generally higher in the upper estuaries where the porosity and organic matter contents of sediments were typically highest. Among 3 measurements in different seasons, the lowest denitrification and oxygen consumption rates were usually observed during winter. Chemical oxygen consumption, as measured using formalin-killed controls, was about 50 % of the total oxygen consumption. A considerable portion (ca 50 %,) of biological oxygen consumption was attributed to nitrification in sediments. We estimated that carbon mineralization by denitrifiers was as much as 40 to 179% of that by aerobic heterotrophs. In the Guadalupe Estuary, denitrification removed about 38 % of the measured inputs of organic and inorganic nitrogen. In the Nueces Estuary, the amount of nitrogen removed by denitrification was ca 2 times greater than the measured nitrogen inputs from the Nueces River and precipitation, suggesting that unmeasured anthropogenic inputs along the perimeter of the estuary were very important for maintaining nitrogen balance.

Publication Info

Marine Ecology Progress Series, ed. S.Y. Newell, Volume 90, 1992, pages 157-167.

Rights

© Marine Ecology Progress Series 1992, Inter-Research.

APA Citation

Yoon, W., & Benner, R. (1992). Denitrification and Oxygen Consumption in Sediments of Two South Texas Estuaries. Marine Ecology Progress Series, 90, 157–167.