scholarly journals The Impact of Sea Embankment Reclamation on Greenhouse Gas GHG Fluxes and Stocks in Invasive Spartina alterniflora and Native Phragmites australis Wetland Marshes of East China

2021 ◽  
Vol 13 (22) ◽  
pp. 12740
Author(s):  
Jian Li ◽  
Zhanrui Leng ◽  
Yueming Wu ◽  
Guanlin Li ◽  
Guangqian Ren ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Greenhouse Gas ◽  
Spartina Alterniflora ◽  
Phragmites Australis ◽  
Salt Marshes ◽  
Coastal Wetlands ◽  
Organic N ◽  
C And N ◽  
The Impact ◽  
Ghg Fluxes

The introduction of embankment seawalls to limit the expansion of the exotic C4 perennial grass Spartina alteniflora Loisel in eastern China’s coastal wetlands has more than doubled in the past decades. Previous research focused on the impact of sea embankment reclamation on the soil organic carbon (C) and nitrogen (N) stocks in salt marshes, whereas no study attempted to assess the impact of sea embankment reclamation on greenhouse gas (GHG) fluxes in such marshes. Here we examined the impact of sea embankment reclamation on GHG stocks and fluxes of an invasive Spartina alterniflora and native Phragmites australis dominated salt marsh in the Dongtai wetlands of China’s Jiangsu province. Sea embankment reclamation significantly decreased soil total organic C by 54.0% and total organic N by 73.2%, decreasing plant biomass, soil moisture, and soil salinity in both plants’ marsh. It increased CO2 emissions by 38.2% and 13.5%, and reduced CH4 emissions by 34.5% and 37.1%, respectively, in the Spartina alterniflora and Phragmites australis marshes. The coastal embankment wall also significantly increased N2O emission by 48.9% in the Phragmites australis salt marsh and reduced emissions by 17.2% in the Spartina alterniflora marsh. The fluxes of methane CH4 and carbon dioxide CO2 were similar in both restored and unrestored sections, whereas the fluxes of nitrous oxide N2O were substantially different owing to increased nitrate as a result of N-loading. Our findings show that sea embankment reclamation significantly alters coastal marsh potential to sequester C and N, particularly in native Phragmites australis salt marshes. As a result, sea embankment reclamation essentially weakens native and invasive saltmarshes’ C and N sinks, potentially depleting C and N sinks in coastal China’s wetlands. Stakeholders and policymakers can utilize this scientific evidence to strike a balance between seawall reclamation and invasive plant expansion in coastal wetlands.

scholarly journals Soil greenhouse gas fluxes from tropical coastal wetlands and alternative agricultural land uses

2021 ◽  
Vol 18 (18) ◽  
pp. 5085-5096
Author(s):  
Naima Iram ◽  
Emad Kavehei ◽  
Damien T. Maher ◽  
Stuart E. Bunn ◽  
Mehran Rezaei Rashti ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Greenhouse Gas ◽  
Coastal Wetlands ◽  
Agricultural Land ◽  
Ghg Emissions ◽  
Climatic Conditions ◽  
Land Uses ◽  
Ghg Mitigation ◽  
Tropical Regions ◽  
Ghg Fluxes

Abstract. Coastal wetlands are essential for regulating the global carbon budget through soil carbon sequestration and greenhouse gas (GHG – CO2, CH4, and N2O) fluxes. The conversion of coastal wetlands to agricultural land alters these fluxes' magnitude and direction (uptake/release). However, the extent and drivers of change of GHG fluxes are still unknown for many tropical regions. We measured soil GHG fluxes from three natural coastal wetlands – mangroves, salt marsh, and freshwater tidal forests – and two alternative agricultural land uses – sugarcane farming and pastures for cattle grazing (ponded and dry conditions). We assessed variations throughout different climatic conditions (dry–cool, dry–hot, and wet–hot) within 2 years of measurements (2018–2020) in tropical Australia. The wet pasture had by far the highest CH4 emissions with 1231±386 mgm-2d-1, which were 200-fold higher than any other site. Dry pastures and sugarcane were the highest emitters of N2O with 55±9 mgm-2d-1 (wet–hot period) and 11±3 mgm-2d-1 (hot-dry period, coinciding with fertilisation), respectively. Dry pastures were also the highest emitters of CO2 with 20±1 gm-2d-1 (wet–hot period). The three coastal wetlands measured had lower emissions, with salt marsh uptake of -0.55±0.23 and -1.19±0.08 gm-2d-1 of N2O and CO2, respectively, during the dry–hot period. During the sampled period, sugarcane and pastures had higher total cumulative soil GHG emissions (CH4+N2O) of 7142 and 56 124 CO2-eqkgha-1yr-1 compared to coastal wetlands with 144 to 884 CO2-eqkgha-1yr-1 (where CO2-eq is CO2 equivalent). Restoring unproductive sugarcane land or pastures (especially ponded ones) to coastal wetlands could provide significant GHG mitigation.

scholarly journals Pollen Geochronology from the Atlantic Coast of the United States during the Last 500 Years

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 362
Author(s):  
Margaret A. Christie ◽  
Christopher E. Bernhardt ◽  
Andrew C. Parnell ◽  
Timothy A. Shaw ◽  
Nicole S. Khan ◽  
...  
Keyword(s):  
United States ◽  
Salt Marsh ◽  
Salt Marshes ◽  
Coastal Wetlands ◽  
Atlantic Coast ◽  
The United States ◽  
Pollen Data ◽  
Sediment Reworking ◽  
Salt Marsh Sediment ◽  
The Impact

Building robust age–depth models to understand climatic and geologic histories from coastal sedimentary archives often requires composite chronologies consisting of multi-proxy age markers. Pollen chronohorizons derived from a known change in vegetation are important for age–depth models, especially those with other sparse or imprecise age markers. However, the accuracy of pollen chronohorizons compared to other age markers and the impact of pollen chronohorizons on the precision of age–depth models, particularly in salt marsh environments, is poorly understood. Here, we combine new and published pollen data from eight coastal wetlands (salt marshes and mangroves) along the Atlantic Coast of the United States (U.S.) from Florida to Connecticut to define the age and uncertainty of 17 pollen chronohorizons. We found that 13 out of 17 pollen chronohorizons were consistent when compared to other age markers (radiocarbon, radionuclide 137Cs and pollution markers). Inconsistencies were likely related to the hyperlocality of pollen chronohorizons, mixing of salt marsh sediment, reworking of pollen from nearby tidal flats, misidentification of pollen signals, and inaccuracies in or misinterpretation of other age markers. Additionally, in a total of 24 models, including one or more pollen chronohorizons, increased precision (up to 41 years) or no change was found in 18 models.

scholarly journals Effect of Organic Amendment Addition on Soil Properties, Greenhouse Gas Emissions and Grape Yield in Semi-Arid Vineyard Agroecosystems

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1477
Author(s):  
Antonio Marín-Martínez ◽  
Alberto Sanz-Cobeña ◽  
Mª Angeles Bustamante ◽  
Enrique Agulló ◽  
Concepción Paredes
Keyword(s):  
Soil Fertility ◽  
Soil Properties ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Organic Amendments ◽  
Organic N ◽  
N2o Emissions ◽  
The Impact ◽  
Semi Arid ◽  
Grape Yield

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell.

The impact of ozone on a salt marsh cordgrass (Spartina alterniflora)

2002 ◽  
Vol 120 (3) ◽  
pp. 701-705 ◽  
Author(s):  
Matthew D Taylor ◽  
Judith P Sinn ◽  
Donald D Davis ◽  
Eva J Pell
Keyword(s):  
Salt Marsh ◽  
Spartina Alterniflora ◽  
The Impact

RELATIONSHIP OF SPARTINA ALTERNIFLORA GROWTH TO SEDIMENT OIL CONTENT FOLLOWING AN OIL SPILL

1987 ◽  
Vol 1987 (1) ◽  
pp. 445-449 ◽  
Author(s):  
Steve K. Alexander ◽  
James W. Webb
Keyword(s):  
Salt Marsh ◽  
Crude Oil ◽  
Spartina Alterniflora ◽  
Oil Spill ◽  
Salt Marshes ◽  
Oil Content ◽  
Biological Effects ◽  
High Concentrations ◽  
Salt Marsh Sediments ◽  
Crude Oil Spill

ABSTRACT A single spill of crude oil in a salt marsh is generally considered to have limited biological effects. A crude oil spill in Dickinson Bayou (in the Galveston Bay system of Texas) in January 1984 provided the opportunity to test this hypothesis in salt marshes exposed to varying amounts of oil. Growth of Spartina alterniflora was unaffected in light to moderately oiled sediments (less than 5 mg oil/g sediment). However, growth was significantly reduced in sediments with high oil content (5 to 51 mg/g) through 18 months. Erosion of shoreline areas with high oil content was evident by 16 months and continued through 32 months. These results demonstrate the adverse effect of high concentrations of crude oil in salt marsh sediments. Each crude oil spill must be evaluated individually with regard to the likelihood of significant accumulation of oil in sediments before a decision is made regarding a cleanup response.

Salt Marsh Remediation and the Deepwater Horizon Oil Spill, the Role of Planting in Vegetation and Macroinvertebrate Recovery

2014 ◽  
Vol 2014 (1) ◽  
pp. 1985-1999 ◽  
Author(s):  
Scott Zengel ◽  
Nicolle Rutherford ◽  
Brittany Bernik ◽  
Zachary Nixon ◽  
Jacqueline Michel
Keyword(s):  
Salt Marsh ◽  
Spartina Alterniflora ◽  
Oil Spill ◽  
Salt Marshes ◽  
Mechanical Treatment ◽  
Reference Conditions ◽  
Deepwater Horizon ◽  
Deepwater Horizon Oil Spill ◽  
Littoraria Irrorata ◽  
Barataria Bay

ABSTRACT The Deepwater Horizon oil spill resulted in persistent heavy oiling in salt marshes, particularly in northern Barataria Bay, Louisiana. Oiling conditions and several ecological variables were compared among reference plots and three types of heavily oiled plots located along a continuous shoreline area in northern Barataria Bay: oiled control plots, mechanical treatment plots, and mechanical treatment plots coupled with vegetation planting (Spartina alterniflora). Data were collected more than three years following initial oiling and two years following cleanup treatments and planting. Salt marsh oiling and associated impacts were apparent across all oiling/treatment classes relative to reference conditions. Mechanical treatment with planting showed the most improvement in oiling conditions and was also effective in re-establishing vegetation cover and plant species composition similar to reference conditions, in contrast to the oiled controls and mechanical treatment plots without planting. Marsh periwinkle (Littoraria irrorata) recovery was limited across all oiling/treatment classes relative to reference. Impacts to fiddler crabs (Uca spp.) were also documented in the heavily oiled plots. Positive influences of mechanical treatment and planting on macroinvertebrate recovery were observed; however, invertebrate recovery may lag the return of Spartina alterniflora by several years. Vegetation planting should be considered as a spill response and emergency restoration option for heavily oiled salt marshes where vegetation impacts are substantial, natural recovery may be lacking or delayed, intensive cleanup treatments are used, or where marsh shorelines are at risk of erosion.

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