Marsh Vegetation Types of the Mississippi River Deltaic Plain

Visser, Jenneke M.; Sasser, Charles E.; Chabreck, Robert H.; Linscombe, R. G.

doi:10.2307/1353283

Cited by 113 publications

(76 citation statements)

References 19 publications

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“…However, because multiple factors influence the distribution of marsh plants, and many species occur over a wide range of salinity conditions, some sites may exist outside of the defined salinity range for a particular wetland type. Six sites each were sampled within four marsh types: fresh, intermediate, brackish, and saline Visser et al 1998) spanning two hydrologic basins, Terrebonne and Barataria (Fig. 1).…”

Section: Site Descriptionmentioning

confidence: 99%

Relationships Between Salinity and Short-Term Soil Carbon Accumulation Rates from Marsh Types Across a Landscape in the Mississippi River Delta

et al. 2017

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Salinity alterations will likely change the plant and environmental characteristics in coastal marshes thereby influencing soil carbon accumulation rates. Coastal Louisiana marshes have been historically classified as fresh, intermediate, brackish, or saline based on resident plant community and position along a salinity gradient. Short-term total carbon accumulation rates were assessed by collecting 10-cm deep soil cores at 24 sites located in marshes spanning the salinity gradient. Bulk density, total carbon content, and the short-term accretion rates obtained with feldspar horizon markers were measured to determine total carbon accumulation rates. Despite some significant differences in soil properties among marsh types, the mean total carbon accumulation rates among marsh types were not significantly different (mean ± std. err. of 190 ± 27 g TC m −2 year −1 ). However, regression analysis indicated that mean annual surface salinity had a significant negative relationship with total carbon accumulation rates. Based on both analyses, the coastal Louisiana total marsh area (1,433,700 ha) accumulates about 2.7 to 3.3 Tg C year −1 .Changing salinities due to increasing relative sea level or resulting from restoration activities may alter carbon accumulation rates in the short term and significantly influence the global carbon cycle.

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Section: Site Descriptionmentioning

confidence: 99%

Relationships Between Salinity and Short-Term Soil Carbon Accumulation Rates from Marsh Types Across a Landscape in the Mississippi River Delta

et al. 2017

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“…Furthermore, changes to channel width force the migration of channel banks that are a primary interface in island [Johnson et al, 1985;Visser et al, 1998;Viparelli et al, 2011] and aquatic [Minello and Rozas, 2002;Roth et al, 2008] ecosystems models. In this study, we show that distributary channels in the proximal WLD are both deepening and widening over time, causing islands to migrate laterally and downstream.…”

Section: Delta Channel Network Evolutionmentioning

confidence: 99%

The morphology and evolution of channels on the Wax Lake Delta, Louisiana, USA

Shaw

Mohrig

Whitman³

2013

JGR Earth Surface

107

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[1] River deltas are classic depositional systems, but a growing body of literature shows that their channel networks can be erosional. Furthermore, this erosion can attack channel beds of consolidated mud that acts as bedrock. To better understand the channel networks of natural deltas and engineered river diversions, we investigate bathymetric and planimetric change, bed cover, and sediment transport in the Wax Lake Delta (WLD) in coastal Louisiana, USA. Channels have eroded up to 40% of modern flow depth between the WLD's initiation in 1973 and 1999. Aerial image analysis shows that channels have widened by 11% between 1991 and 2009, forcing the downstream migration of islands. Channel beds are composed of 85-98% muddy bedrock, with the remainder covered by alluvial sands. Water velocity, grain size, and suspended sand concentration measurements during the 2009 spring flood show that almost all available grain sizes are transported in suspension. Flow was supply limited during this period, with the calculated sand concentration at the height of the bed load layer is 1-4 orders of magnitude smaller than predicted for saturated sand transport. We test "the cover effect" and "the tools effect" previously proposed for bedrock erosion in upland river channels. Bedrock erosion and alluvial cover are anti-correlated (the cover effect), but the observations do not closely follow previously proposed relationships. The difference in erosion rate between clear water and sand-rich water shows that abrasion by sand (the tools effect) accounts for 51% ± 56% of bedrock erosion when it is present.

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“…We used marsh vegetation to define our marsh types because vegetation reflects the salinity conditions of the recent past, as marsh plants respond to, and integrate local salinity patterns (Visser et al 1998, Rozas & Minello 2010. Furthermore, salinity ranges were a major consideration in our decision to select marsh types based on dominant marsh vegetation (i.e.…”

Section: Study Sitesmentioning

confidence: 99%

Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types

Kang

King²

2013

Aquat. Biol.

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Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes. KEY WORDS: Coastal marsh · Aquatic macroinvertebrate assemblage · Hydrologic connectivity · Functional feeding groupsResale or republication not permitted without written consent of the publisher

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Marsh Vegetation Types of the Mississippi River Deltaic Plain

Cited by 113 publications

References 19 publications

Relationships Between Salinity and Short-Term Soil Carbon Accumulation Rates from Marsh Types Across a Landscape in the Mississippi River Delta

Relationships Between Salinity and Short-Term Soil Carbon Accumulation Rates from Marsh Types Across a Landscape in the Mississippi River Delta

The morphology and evolution of channels on the Wax Lake Delta, Louisiana, USA

Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types

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