scholarly journals Seasonal variation in apparent conductivity and soil salinity at two Narragansett Bay, RI salt marshes

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8074
Author(s):  
Richard McKinney ◽  
Alana Hanson ◽  
Roxanne Johnson ◽  
Michael Charpentier
Keyword(s):  
Salt Marsh ◽  
Soil Salinity ◽  
Salt Marshes ◽  
Temporal Trends ◽  
Narragansett Bay ◽  
Spatial And Temporal Variability ◽  
Apparent Conductivity ◽  
Marsh Sediments ◽  
Salt Marsh Sediments ◽  
Over Time

Measurement of the apparent conductivity of salt marsh sediments using electromagnetic induction (EMI) is a rapid alternative to traditional methods of salinity determination that can be used to map soil salinity across a marsh surface. Soil salinity measures can provide information about marsh processes, since salinity is important in determining the structure and function of tidally influenced marsh communities. While EMI has been shown to accurately reflect salinity to a specified depth, more information is needed on the potential for spatial and temporal variability in apparent conductivity measures that may impact the interpretation of salinity data. In this study we mapped soil salinity at two salt marshes in the Narragansett Bay, RI estuary monthly over the course of several years to examine spatial and temporal trends in marsh salinity. Mean monthly calculated salinity was 25.8 ± 5.5 ppt at Narrow River marsh (NAR), located near the mouth of the Bay, and 17.7 ± 5.3 ppt at Passeonkquis marsh (PAS) located in the upper Bay. Salinity varied seasonally with both marshes, showing the lowest values (16.3 and 8.3 ppt, respectively) in April and highest values (35.4 and 26.2 ppt, respectively) in August. Contour plots of calculated salinities showed that while the mean whole-marsh calculated salinity at both sites changed over time, within-marsh patterns of higher versus lower salinity were maintained at NAR but changed over time at PAS. Calculated salinity was significantly negatively correlated with elevation at NAR during a sub-set of 12 sample events, but not at PAS. Best-supported linear regression models for both sites included one-month and 6-month cumulative rainfall, and tide state as potential factors driving observed changes in calculated salinity. Mapping apparent conductivity of salt marsh sediments may be useful both identifying within-marsh micro-habitats, and documenting marsh-wide changes in salinity over time.

scholarly journals Distribution and Diversity of Archaeal and Bacterial Ammonia Oxidizers in Salt Marsh Sediments

2009 ◽  
Vol 75 (23) ◽  
pp. 7461-7468 ◽  
Author(s):  
Nicole S. Moin ◽  
Katelyn A. Nelson ◽  
Alexander Bush ◽  
Anne E. Bernhard
Keyword(s):  
Salt Marsh ◽  
16S Rrna ◽  
New England ◽  
Water Column ◽  
Salt Marshes ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Group I ◽  
Marsh Sediments ◽  
Salt Marsh Sediments

ABSTRACT Diversity and abundance of ammonia-oxidizing Betaproteobacteria (β-AOB) and archaea (AOA) were investigated in a New England salt marsh at sites dominated by short or tall Spartina alterniflora (SAS and SAT sites, respectively) or Spartina patens (SP site). AOA amoA gene richness was higher than β-AOB amoA richness at SAT and SP, but AOA and β-AOB richness were similar at SAS. β-AOB amoA clone libraries were composed exclusively of Nitrosospira-like amoA genes. AOA amoA genes at SAT and SP were equally distributed between the water column/sediment and soil/sediment clades, while AOA amoA sequences at SAS were primarily affiliated with the water column/sediment clade. At all three site types, AOA were always more abundant than β-AOB based on quantitative PCR of amoA genes. At some sites, we detected 109 AOA amoA gene copies g of sediment−1. Ratios of AOA to β-AOB varied over 2 orders of magnitude among sites and sampling dates. Nevertheless, abundances of AOA and β-AOB amoA genes were highly correlated. Abundance of 16S rRNA genes affiliated with Nitrosopumilus maritimus, Crenarchaeota group I.1b, and pSL12 were positively correlated with AOA amoA abundance, but ratios of amoA to 16S rRNA genes varied among sites. We also observed a significant effect of pH on AOA abundance and a significant salinity effect on both AOA and β-ΑΟΒ abundance. Our results expand the distribution of AOA to salt marshes, and the high numbers of AOA at some sites suggest that salt marsh sediments serve as an important habitat for AOA.

Metal speciation in salt marsh sediments: Influence of halophyte vegetation in salt marshes with different morphology

2015 ◽  
Vol 167 ◽  
pp. 248-255 ◽  
Author(s):  
Sílvia Pedro ◽  
Bernardo Duarte ◽  
Pedro Raposo de Almeida ◽  
Isabel Caçador
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Metal Speciation ◽  
Marsh Sediments ◽  
Salt Marsh Sediments

scholarly journals Topological and Morphological Controls on Morphodynamics of Salt Marsh Interiors

2021 ◽  
Vol 9 (3) ◽  
pp. 311
Author(s):  
Ben R. Evans ◽  
Iris Möller ◽  
Tom Spencer
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
East Coast ◽  
Marsh Surface ◽  
Coastal Environments ◽  
Coastal System ◽  
Morphological Segmentation ◽  
The Usa ◽  
The Uk ◽  
Over Time

Salt marshes are important coastal environments and provide multiple benefits to society. They are considered to be declining in extent globally, including on the UK east coast. The dynamics and characteristics of interior parts of salt marsh systems are spatially variable and can fundamentally affect biotic distributions and the way in which the landscape delivers ecosystem services. It is therefore important to understand, and be able to predict, how these landscape configurations may evolve over time and where the greatest dynamism will occur. This study estimates morphodynamic changes in salt marsh areas for a regional domain over a multi-decadal timescale. We demonstrate at a landscape scale that relationships exist between the topology and morphology of a salt marsh and changes in its condition over time. We present an inherently scalable satellite-derived measure of change in marsh platform integrity that allows the monitoring of changes in marsh condition. We then demonstrate that easily derived geospatial and morphometric parameters can be used to determine the probability of marsh degradation. We draw comparisons with previous work conducted on the east coast of the USA, finding differences in marsh responses according to their position within the wider coastal system between the two regions, but relatively consistent in relation to the within-marsh situation. We describe the sub-pixel-scale marsh morphometry using a morphological segmentation algorithm applied to 25 cm-resolution maps of vegetated marsh surface. We also find strong relationships between morphometric indices and change in marsh platform integrity which allow for the inference of past dynamism but also suggest that current morphology may be predictive of future change. We thus provide insight into the factors governing marsh degradation that will assist the anticipation of adverse changes to the attributes and functions of these critical coastal environments and inform ongoing ecogeomorphic modelling developments.

Long-Term Fertilization Alters Nitrous Oxide Cycling Dynamics in Salt Marsh Sediments

2021 ◽  
Author(s):  
Xuefeng Peng ◽  
Qixing Ji ◽  
John H. Angell ◽  
Patrick J. Kearns ◽  
Jennifer L. Bowen ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Salt Marsh ◽  
Marsh Sediments ◽  
Salt Marsh Sediments
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