Marsh Mat Flotation in the Louisiana Delta Plain

Swarzenski, Christopher M.; Swenson, Erick M.; Sasser, Charles E.; Gosselink, James G.

doi:10.2307/2261094

Cited by 49 publications

(54 citation statements)

References 18 publications

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“…The mat may settle on the underlying substrate during low water events. During flooding, water may flow above or below the mat (Swarzenski et al, 1991). Saline water enters Lake Salvador through tidal inlets from the Gulf of Mexico (maximum salinity = 4; Swarzenski et al, 1991) so that floating marshes near Lake Salvador have a range of salinity from freshwater to brackish (Swarzenski & Swenson, 1994).…”

Section: Study Areamentioning

confidence: 99%

“…During flooding, water may flow above or below the mat (Swarzenski et al, 1991). Saline water enters Lake Salvador through tidal inlets from the Gulf of Mexico (maximum salinity = 4; Swarzenski et al, 1991) so that floating marshes near Lake Salvador have a range of salinity from freshwater to brackish (Swarzenski & Swenson, 1994). We studied freshwater marshes in the Lake Salvador Management Area, which had lower levels of salinity than the intermediate type (Swarzenski et al, 1991).…”

Section: Study Areamentioning

confidence: 99%

“…Saline water enters Lake Salvador through tidal inlets from the Gulf of Mexico (maximum salinity = 4; Swarzenski et al, 1991) so that floating marshes near Lake Salvador have a range of salinity from freshwater to brackish (Swarzenski & Swenson, 1994). We studied freshwater marshes in the Lake Salvador Management Area, which had lower levels of salinity than the intermediate type (Swarzenski et al, 1991). The dominant species in the Lake Salvador Management Area are of the C 3 assimilation type including Cyperus haspan, Hydrocotyle verticillata, Panicum hemitomum, Sagittaria lancifolia, and S. americanus (Swarzenski et al, 1991).…”

Section: Study Areamentioning

confidence: 99%

“…We studied freshwater marshes in the Lake Salvador Management Area, which had lower levels of salinity than the intermediate type (Swarzenski et al, 1991). The dominant species in the Lake Salvador Management Area are of the C 3 assimilation type including Cyperus haspan, Hydrocotyle verticillata, Panicum hemitomum, Sagittaria lancifolia, and S. americanus (Swarzenski et al, 1991).…”

Section: Study Areamentioning

confidence: 99%

“…The species of the floating marshes of Lake Salvador in coastal Louisiana are excellent candidates for studies of potential multifactorial interactions in wetland environments. These wetlands constitute some of the southernmost freshwater wetlands in central North America (Swarzenski et al, 1991), and are thus likely to be directly impacted in the future by shifts in levels of CO 2 , water level, and salinity along the Gulf Coast. These wetlands lie within the Barataria Basin of the Mississippi River Deltaic Plain in the most recently abandoned channel of the Mississippi River (Swarzenski et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

Middleton

McKee

2011

Hydrobiologia

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Higher atmospheric concentrations of CO 2 can offset the negative effects of flooding or salinity on plant species, but previous studies have focused on mature, rather than regenerating vegetation. This study examined how interacting environments of CO 2 , water regime, and salinity affect seed germination and seedling biomass of floating freshwater marshes in the Mississippi River Delta, which are dominated by C 3 grasses, sedges, and forbs. Germination density and seedling growth of the dominant species depended on multifactor interactions of CO 2 (385 and 720 ll l -1 ) with flooding (drained, ?8-cm depth, ?8-cm depthgradual) and salinity (0, 6% seawater) levels. Of the three factors tested, salinity was the most important determinant of seedling response patterns. Species richness (total = 19) was insensitive to CO 2 . Our findings suggest that for freshwater marsh communities, seedling response to CO 2 is species-specific and secondary to salinity and flooding effects. Elevated CO 2 did not ameliorate flooding or salinity stress. Consequently, climate-related changes in sea level or human-caused alterations in hydrology may override atmospheric CO 2 concentrations in driving shifts in this plant community. The results of this study suggest caution in making extrapolations from species-specific responses to community-level predictions without detailed attention to the nuances of multifactor responses.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

Middleton

McKee

2011

Hydrobiologia

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Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

Krauss

Holm²,

Perez³

et al. 2016

JGR Biogeosciences

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Neubauer, Scott C.; and Raynie, Richard C., "Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance" (2016 Abstract Coastal marshes take up atmospheric CO 2 while emitting CO 2 , CH 4 , and N 2 O. This ability to sequester carbon (C) is much greater for wetlands on a per area basis than from most ecosystems, facilitating scientific, political, and economic interest in their value as greenhouse gas sinks. However, the greenhouse gas balance of Gulf of Mexico wetlands is particularly understudied. We describe the net ecosystem exchange (NEE c ) of CO 2 and CH 4 using eddy covariance (EC) in comparison with fluxes of CO 2 , CH 4 , and N 2 O using chambers from brackish and freshwater marshes in Louisiana, USA. From EC, we found that 182 g C m À2 yr À1 was lost through NEE c from the brackish marsh. Of this, 11 g C m À2 yr À1 resulted from net CH 4 emissions and the remaining 171 g C m À2 yr À1 resulted from net CO 2 emissions. In contrast, À290 g C m 2 yr À1 was taken up through NEE c by the freshwater marsh, with 47 g C m À2 yr À1 emitted as CH 4 and À337 g C m À2 yr À1 taken up as CO 2 . From chambers, we discovered that neither site had large fluxes of N 2 O. Sustained-flux greenhouse gas accounting metrics indicated that both marshes had a positive (warming) radiative balance, with the brackish marsh having a substantially greater warming effect than the freshwater marsh. That net respiratory emissions of CO 2 and CH 4 as estimated through chamber techniques were 2-4 times different from emissions estimated through EC requires additional understanding of the artifacts created by different spatial and temporal sampling footprints between techniques.

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Effects of root mat buoyancy and heterogeneity on floating fen hydrology

Stofberg

Engelen

Witte³

et al. 2016

Ecohydrology

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Floating fen ecosystems are home to several protected habitats and species. Their development and conservation require special attention regarding water management. Although they are known to be heterogeneous and partially buoyant, their root mats are simulated in hydrological models as homogeneous, static systems. The objective of this study is to quantify root mat heterogeneity and buoyancy and to assess their effects on groundwater flow and transport, and to determine if these factors need to be taken into account in modelling. We conducted field measurements of root mat heterogeneity and buoyancy in the 'Nieuwkoopse Plassen', the Netherlands. We found that hydraulic conductivity varied over four orders of magnitude and negatively correlated with degree of decomposition, resulting in a zonation of high conductivity near the surface and low conductivity in the deeper layers. Also, we found that the root mat moved vertically with the surface water. It became more buoyant with higher temperatures, but less buoyant with increasing groundwater levels relative to the surface. We implemented the findings in a semi-steady state hydrological model of a floating fen to compare the effects with other parameters. The profound heterogeneity had a limited effect on the water budget, but a clear effect on the flow lines and thus should be taken into account when modelling transport processes in floating fens. Although buoyancy affected the relative groundwater level near the root mat edge, it did not affect the water budget or the flow lines and may therefore be neglected in water budget modelling.

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Marsh Mat Flotation in the Louisiana Delta Plain

Cited by 49 publications

References 18 publications

Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

Can elevated CO2 modify regeneration from seed banks of floating freshwater marshes subjected to rising sea-level?

Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

Effects of root mat buoyancy and heterogeneity on floating fen hydrology

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