Sedimentation, Nutrient Accumulation, and Early Diagenesis in Louisiana Barataria Basin Coastal Marshes

Hatton, R. S.; Patrick, W. H.; DeLaune, R. D.

doi:10.1016/b978-0-12-404070-0.50021-1

Cited by 20 publications

(12 citation statements)

References 19 publications

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“…One study found net C accumulation rate of 183, 296, and 224 g C m −2 year −1 for Barataria Basin saltwater, brackish, and freshwater marshes, suggesting relatively the same amount of carbon accumulation along a salinity gradient (Smith et al 1983). Hatton et al (1982) and (1983) reported similar C accumulation rates for these marshes. Average OM accumulation rate for marshes were converted where applicable to organic carbon (by multiplying OM by 0.56).…”

Section: Vertical Marsh Accretion and Soil Carbon Accumulation In Lousupporting

confidence: 68%

Will coastal wetlands continue to sequester carbon in response to an increase in global sea level?: a case study of the rapidly subsiding Mississippi river deltaic plain

2011

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The highly visible coastal phenomenon of wetland loss in coastal Louisiana (LA) was examined through the prism of carbon accumulation and loss. Carbon storage or sequestration in rapidly subsiding LA coastal marsh soils was based on vertical marsh accretion and aerial change data. Marshes sequester significant amount of carbon through vertical accretion however, large amounts of carbon previously sequestration in the soil profile is lost through annual deterioration of these coastal marshes. Hurricanes, such as Katrina and Rita, have triggered instantaneous large carbon losses of sequestered soil carbon through the destruction of large areas of marsh. This analysis shows proposed coastal restoration efforts will not be sufficient to restore carbon losses by storms and marsh deterioration. Further, we have estimated the economic benefit of carbon sequestration for coastal wetland restoration efforts. Results show that LA coastal marshes may not serve as a net sink of carbon. These results may serve as a predictor of the impact of future predictions of increasing global sea level rise on carbon sequestration for other coastal regions.

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Section: Vertical Marsh Accretion and Soil Carbon Accumulation In Lousupporting

confidence: 68%

Will coastal wetlands continue to sequester carbon in response to an increase in global sea level?: a case study of the rapidly subsiding Mississippi river deltaic plain

2011

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“…¶ From DeLaune and Patrick (1980), DeLaune et al (1981), Hatton et al (1982), Smith et al (1983), Craft et al (1993), Craft and Reader (1997), and this study. Havens et al (1995) (no depth given), Levin et al (1996) (0-6 cm), Craft and Reader (1997) (0-5 cm), Levin et al (1998) (0-6 cm), and this study (0-5 cm).…”

Section: Discussionmentioning

confidence: 98%

Twenty-Five Years of Ecosystem Development of Constructed Spartina alterniflora (Loisel) Marshes

Craft¹,

Reader²,

Sacco³

et al. 1999

Ecological Applications

150

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Wetland creation and restoration are frequently used to replace ecological functions and values lost when natural wetlands are degraded or destroyed. On many sites, restoration of ecological attributes such as secondary production, habitat/species diversity, and wetland soil characteristics do not occur within the first decade, and no long-term studies exist to document the length of time required to achieve complete restoration of wetland dependent functions and values. Characteristics of community structure (macrophyte aboveground biomass, macro-organic matter [MOM], benthic invertebrates) and ecosystem processes (soil development, organic C, N, and P accumulation) of two constructed Spartina alterniflora (Loisel) marshes (established 1971 and 1974) and paired natural S. alterniflora marshes in North Carolina were periodically measured during the past 25 yr. On constructed marshes, the macrophyte community developed quickly, and within 5 to 10 yr, aboveground biomass and MOM were equivalent to or exceeded corresponding values in natural marshes. After 15-25 yr, benthic infauna density and species richness were greater than in the natural marshes. Soil bulk density decreased, and organic C and total N increased over time in constructed marshes, but after 25 yr, soil organic C and N reservoirs were much smaller than in a 2000-yr-old natural marsh. Organic C accumulation was similar in constructed and natural marshes with 12-24% of the net primary production buried annually. Nitrogen accumulation was much higher in constructed marshes (7-12 g · m Ϫ2 · yr Ϫ1 ) than in natural marshes (2-5 g · m Ϫ2 · yr Ϫ1 ), reflecting the open biogeochemical cycles and paucity of N in these young ecosystems. Different ecological attributes develop at different rates, with primary producers achieving equivalence during the first 5 yr, followed by the benthic infauna community 5-10 yr later. Accumulation of soil nutrients to levels similar to those of reference marshes may require more time.

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“…In this system, removal is primarily by phytoplankton uptake with only moderate reductions by denitrifications observed in this open water system (Roy and White, 2012;Roy et al, 2013). Researchers agree coastal wetlands can serve as a buffer and sink for nutrients from upland sources that cause eutrophication in coastal marine systems (Hatton et al, 1982;Reddy et al, 1993;Lane et al, 1999;VanZomeren et al, 2013), but the physical conditions in coastal ecosystems can be highly dynamic, reducing the predictability of ecological functions like NO 3 removal. In particular, pulsing events, such as river floods and coastal storm surges, are a natural attribute of coastal wetlands with some positive consequences, including promoting plant productivity, sediment deposition, and wetland soil accretion (Nyman et al, 1990;Day et al, 1995).…”

mentioning

confidence: 97%

Effect of Fluctuating Salinity on Potential Denitrification in Coastal Wetland Soil and Sediments

Marks

Chambers

White

2016

Soil Science Society of America Journal

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The coastal wetlands of southern Louisiana provide an ideal environment for removing nitrate (NO 3 -) from the Mississippi River before discharge into the gulf of Mexico where it can contribute to hypoxia. However, denitrification, the primary mechanism of excess N removal, may be sensitive to the fluctuating salinities that characterize coastal wetlands. Salinity can shift from salt to fresh during river inflows, or from fresh to salt during storm surge events. This study investigated the impact of shifting salinity on potential denitrification rates in marsh soils and bayou sediments from the fresh and salt marshes of Brenton Sound estuary. Potential denitrification rates were quantified using bottle incubations for both short-term (2 d), and longer-term (11 d) studies. Fresh marsh sites had higher denitrification enzyme activity (DEA), but all soils and sediments achieved high denitrification when exposed to ideal conditions. Pulses of freshwater (0 ppt) in salt marsh soils decreased potential denitrification rates by 98% for an 11-d study, indicating the rapid opening of a freshwater diversion could significantly reduce that ability of coastal wetlands to provide significant nutrient-removal before discharge to the coastal ocean. Pulses of intermediate salinity (15 ppt) water stimulated denitrification rates in the fresh marsh soil by 75%, while full salinity seawater (35 ppt) suppressed potential denitrification by 73% for 11 d. This research demonstrates the sensitivity of the denitrifying microbial consortia to rapid shifts in salinity and this information can be used to guide water managers on maximizing NO 3 removal in Mississippi River surface water diversions.Abbreviations: DEA, denitrification enzyme activity; DI, deionized; DOC, dissolved organic carbon; MBC, microbial biomass carbon; TOC, total organic carbon.from the river, primarily through denitrification, to eliminate hypoxia in the Gulf of Mexico (Mitsch et al., 2001). While this magnitude of wetland restoration may not be feasible, a few large-scale river reconnection projects have been implemented in the Louisiana coastal zone, called diversion projects. For example, the Davis Pond freshwater diversion (completed in 2002 with a maximum discharge rate of 302 m 3 s -1 ) was designed to combat saltwater intrusion and land loss in Barataria Basin . However, it has also effectively reduced surface wa- Core Ideas• Fresh water pulse to salt marsh soil reduced denitrification.• Salt water reduced denitrification by 73% in fresh marsh soil.• Coastal storm surges can dramatically reduce denitrification.• River flood pulses can reduce salt marsh soil denitrification.

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Sedimentation, Nutrient Accumulation, and Early Diagenesis in Louisiana Barataria Basin Coastal Marshes

Cited by 20 publications

References 19 publications

Will coastal wetlands continue to sequester carbon in response to an increase in global sea level?: a case study of the rapidly subsiding Mississippi river deltaic plain

Will coastal wetlands continue to sequester carbon in response to an increase in global sea level?: a case study of the rapidly subsiding Mississippi river deltaic plain

Twenty-Five Years of Ecosystem Development of Constructed Spartina alterniflora (Loisel) Marshes

Effect of Fluctuating Salinity on Potential Denitrification in Coastal Wetland Soil and Sediments

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