Knauss legislative fellowships in Congress help build careers — and they're fun and educational. See our video and fact sheet for details.
Research Publications: UM-SG-RS-2012-15
Title:
Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams.
Year:
2012Authors:
Newcomer, TA; Kaushal, SS; Mayer, PM; Shields, AR; Canuel, EA; Groffman, PM; Gold, AJSource:
Ecological Monographs 82 ( 4 ) : 449 - 466DOI:
10.1890/12-0458.1Abstract:
Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrification at the riparian-stream interface. Field measurements of streamwater chemistry, organic carbon characterization, and laboratory-based denitrification experiments were completed at two forested, two restored, and two unrestored urban streams at the Baltimore Long-Term Ecological Research site, Maryland, USA. Dissolved organic carbon (DOC) and nitrate loads increased with runoff according to a power-law function that varied across sites. Stable isotopes and molar C:N ratios suggested that stream particulate organic matter (POM) was a mixture of periphyton, leaves, and grass that varied across site types. Stable-isotope signatures and lipid biomarker analyses of sediments showed that terrestrial organic carbon sources in streams varied as a result of riparian vegetation. Laboratory experiments indicated that organic carbon amendments significantly increased rates of denitrification (35.1 +/- 9.4 ng N.[g dry sediment]-1.h-1; mean +/- SE) more than nitrate amendments (10.4 +/- 4.0 ng N.[g dry sediment]-1.h-1) across streamflow conditions and sites. Denitrification experiments with naturally occurring carbon sources showed that denitrification was significantly higher with grass clippings from home lawns (1244 +/- 331 ng N.g dry sediment-1.h-1), and overall unrestored urban sites showed significantly higher denitrification rates than restored and forest sites. We found that urbanization influences organic carbon sources and quality in streams, which can have substantial downstream impacts on ecosystem services such as denitrification.
Related Research Project(s) Funded by Maryland Sea Grant:
Maryland Sea Grant Topic(s):
'Related Research Project(s)' link to details about research projects funded by Maryland Sea Grant that led to this publication. These details may include other impacts and accomplishments resulting from the research.
'Maryland Sea Grant Topic(s)' links to related pages on the Maryland Sea Grant website.
Program Announcements
News and Blogs
Featured Fellow
Leone Yisrael is a cephalopod-loving scuba diver, cook, and loves to try new activities. She conducts genetic analysis and fieldwork at the Smithsonian Environmental Research Center through the Coastal Disease Ecology Lab.
Featured Research Project
Exploring the Use of Benthic Microbial Fuel Cells to Remove Sulfide While Harvesting Energy from Oyster Aquaculture Biodeposits
Oyster aquaculture is a rapidly growing industry in Maryland’s Chesapeake waters which stimulates economic activity and may provide a host of ecosystem benefits. A potential concern associated with the intensification of the oyster aquaculture is the local production and accumulation of oyster biodeposits, which can lead to a porewater sulfide accumulation and declining bioturbation, symptoms of declining ecosystem function. Sulfide is naturally removed from the seafloor by the interactions between bioturbating infauna and sulfide oxidizing bacteria.
Chesapeake Quarterly Magazine
A Growing Industry: Advancing Oyster Aquaculture in Maryland
