scholarly journals Contrasting latitudinal clines of nematode diversity in Spartina alterniflora salt marshes between native and introduced ranges

2020 ◽  
Vol 26 (5) ◽  
pp. 623-631
Author(s):  
Youzheng Zhang ◽  
Bo Li ◽  
Jihua Wu ◽  
Steven C. Pennings
1980 ◽  
Vol 7 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Rick A. Linthurst ◽  
Ernest D. Seneca

Spartina alterniflora is the dominant endemic saltmarsh angiosperm along the East and Gulf coasts of the United States. Dieback of S. alterniflora became evident through aerial surveys of the Lower Cape Fear Estuary of North Carolina. The areas affected varied in size, the largest being greater than 40 ha in areal extent. As S. alterniflora productivity losses can subsequently affect the productivity of the estuarine detritus-based food-web, studies were initiated in 1975 to examine the dieback phenomenon, follow successional trends, and determine the recolonization potential of S. alterniflora in dieback-affected salt-marshes.Three S. alterniflora dieback sites in the Lower Cape Fear Estuary were selected for study. Two of the sites, both above mean high-water, were recolonized by Salicornia europaea, Distichlis spicata, Scirpus robustus, Spartina patens, and S. alterniflora. At a third site, found to be below mean high-water, all volunteer plants were of S. alterniflora. Final stabilization of all three sites was mainly by S. alterniflora, with the living standing-crop biomass ranging from 341 to 1,565 g/m2 in September of 1978.Experimental plots within each of the three dieback sites were sprigged with S. alterniflora plants from three sources: (i) sandy dredge-material, (ii) volunteer plants within affected sites, and (iii) unaffected sites near the dieback areas. The success of these sprigs was strongly site-dependent. It is suggested that the plants used for revegetation of dieback sites should be obtained from areas similar to the site that is being transplanted and/or plants which have large rhizome systems.


2001 ◽  
Vol 67 (11) ◽  
pp. 5308-5314 ◽  
Author(s):  
Charles R. Lovell ◽  
Michael J. Friez ◽  
John W. Longshore ◽  
Christopher E. Bagwell

ABSTRACT DNA was extracted from dry standing dead Spartina alterniflora stalks as well as dry Spartinawrack from the North Inlet (South Carolina) and Sapelo Island (Georgia) salt marshes. Partial nifH sequences were PCR amplified, the products were separated by denaturing gradient gel electrophoresis (DGGE), and the prominent DGGE bands were sequenced. Most sequences (109 of 121) clustered with those from α-Proteobacteria, and 4 were very similar (>99%) to that of Azospirillum brasilense. Seven sequences clustered with those from known γ-Proteobacteria and five with those from known anaerobic diazotrophs. The diazotroph assemblages associated with dead Spartina biomass in these two salt marshes were very similar, and relatively few major lineages were represented.


1987 ◽  
Vol 1987 (1) ◽  
pp. 445-449 ◽  
Author(s):  
Steve K. Alexander ◽  
James W. Webb

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.


2014 ◽  
Vol 2014 (1) ◽  
pp. 1985-1999 ◽  
Author(s):  
Scott Zengel ◽  
Nicolle Rutherford ◽  
Brittany Bernik ◽  
Zachary Nixon ◽  
Jacqueline Michel

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.


2017 ◽  
Author(s):  
Tracy Elsey-Quirk ◽  
Viktoria Unger

Abstract. Environmental conditions have a strong influence on rates plant productivity and decomposition. In salt marshes, hydrology and salinity are important regulators of plant and soil processes, which, in turn, can influence the rate at which marsh ecosystems accumulate C and adjust to sea-level rise. For this study, we examined the influence of multivariate environmental conditions on belowground ingrowth (roots + rhizomes), decomposition and biomass in marshes dominated by Spartina alterniflora across two estuaries and a range of geomorphic settings. Secondly, we examined the influence of belowground plant biomass to soil C density, and C (labile and refractory) accumulation and accretion rates. Study locations occupied a full range of tidal elevations from below mean low water to above mean high water. Salinities ranged from 7–40, and soil properties also varied across marshes. While many of the environmental parameters were correlated across marshes, belowground ingrowth of S. alterniflora was negatively influenced by mean low water height, such that root growth increased with more drainage. Belowground decay rate increased with increasing salinity, but ultimately the percent of mass remaining was similar across marshes, averaging 59 ± 1 %. Above- and belowground biomass dynamics were estuary-dependent. In the coastal lagoon estuary, less flooding and a higher sedimentation rate favored above-and belowground biomass, which, in turn, increased soil C accumulation and accretion rates. Biomass dynamics in the coastal plain estuary, for the most part, were unrelated to environmental predictor variables, and had little influence on the accumulation of soil C or accretion rate. These findings indicate that mineral sedimentation is of utmost importance for promoting belowground biomass and soil C accumulation in sediment-limited systems while in minerogenic systems, belowground biomass may not scale with C accumulation and accretion, which may be influenced more by smaller submillimetre-sized C particles.


2021 ◽  
Vol 13 (22) ◽  
pp. 12740
Author(s):  
Jian Li ◽  
Zhanrui Leng ◽  
Yueming Wu ◽  
Guanlin Li ◽  
Guangqian Ren ◽  
...  

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.


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