EPA Science Inventory

Death by Ulva

Citation:

Watson, E., C. Wigand, A. Oczkowski, K. Sundberg, D. Vendettuoli, K. Saliba, AND J. Morris. Death by Ulva. Presented at New England Estuarine Research Society (NEERS) Spring Meeting, Salem, MA, May 01 - 03, 2014.

Description:

We report on a series of field and laboratory mesocosm experiments where we examined the effects of two levels of decomposing Ulva on Spartina alterniflora growth, soil biogeochemistry, and nitrogen dynamics. Monitoring of porewater revealed rapid mineralization to ammonium from decomposing Ulva, with porewater levels quickly attaining potentially toxic concentrations. In addition, Ulva soil amendments were associated with elevated porewater sulfide levels. Plant uptake of Ulva-derived nitrogen was documented using an 15N label, but higher nitrogen availability did not subsidize growth. In fact, higher levels of Ulva exposure resulted in pronounced reductions in above and belowground productivity, while lower levels of Ulva exposure resulted in reductions in belowground productivity only. Our findings support the hypothesis that decaying Ulva mats may create hotspots of adverse physiochemical conditions in salt marshes, similar to those reported for benthic and tidal flat habitats. Furthermore, decaying Ulva mats may compromise the erosion resistance of salt marshes via decreased plant belowground biomass. We conclude that additional field and laboratory studies are needed to establish more concretely which Ulva related stressors are primary, and whether similarly adverse responses are observed under natural field conditions.

Purpose/Objective:

This presentation will share information on recent findings on negative impacts of the macroalgae, Ulva, on salt marsh plant growth.

URLs/Downloads:

EW_NEERS_ULVA ABSTRACT_2014.PDF   (PDF,NA pp, 45.141 KB,  about PDF)

Record Details:

Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Completion Date: 05/13/2014
Record Last Revised: 05/13/2014
Record Created: 05/13/2014
Record Released: 05/13/2014
OMB Category: Other
Record ID: 275615

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

ATLANTIC ECOLOGY DIVISION

HABITATS EFFECT BRANCH