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.

Fungi on Juncus roemerianus. 8. New bitunicate ascomycetes

1996 ◽  
Vol 74 (11) ◽  
pp. 1830-1840 ◽  
Author(s):  
Jan Kohlmeyer ◽  
Brigitte Volkmann-Kohlmeyer ◽  
Ove E. Eriksson
Keyword(s):  
United States ◽  
Salt Marsh ◽  
Salt Marshes ◽  
New Genus ◽  
East Coast ◽  
The United States ◽  
The Other ◽  
Juncus Roemerianus

Heleiosa barbatula gen. et sp.nov., Massariosphaeria erucacea sp.nov., and Scirrhia annulata sp.nov. are described from Juncus roemerianus in salt marshes of the United States east coast. Whereas H. barbatula is very rare, the other two species do not show a seasonality because they occurred in almost every one of the monthly collections made throughout 2 years. The new genus Heleiosa is of unknown affinity but may belong to Dothideales s.l. Keywords: ascomycetes, Heleiosa, Juncus, Massariosphaeria, salt marsh, Scirrhia.

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 Salt Marsh Claviceps purpurea in Native and Invaded Spartina Marshes in Northern California

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 380-386 ◽  
Author(s):  
A. J. Fisher ◽  
J. M. DiTomaso ◽  
T. R. Gordon ◽  
B. J. Aegerter ◽  
D. R. Ayres
Keyword(s):  
United States ◽  
Salt Marsh ◽  
San Francisco ◽  
Atlantic Coast ◽  
The United States ◽  
San Francisco Estuary ◽  
Claviceps Purpurea ◽  
Northern California ◽  
Native Plant ◽  
Worldwide Distribution

The fungal pathogen Claviceps purpurea (subgroup G3) has a worldwide distribution on salt marsh Spartina spp. In Northern California (United States), native Spartina foliosa sustains high rates of infection by G3 C. purpurea in marshes north of the San Francisco Estuary. Invasive populations of S. alterniflora and S. alterniflora × foliosa hybrids are virtually disease free in the same estuary, although S. alterniflora is host to G3 C. purpurea in its native range (Atlantic Coast of the United States). Greenhouse inoculation experiments showed no differences in susceptibility among S. foliosa, S. alterniflora, and Spartina hybrids. Under field conditions, S. foliosa sustained a higher incidence of disease in coastal marshes than in marshes within the bay. This geographic effect may be attributable to environmental differences between the coast and the bay proper, with the former being more conducive to infection by C. purpurea. Seed set of S. foliosa spikelets was 40 to 70% lower on infected than on uninfected inflorescences, but seed germination was not affected. The C. purpurea epidemic on S. foliosa on the coast north of the San Francisco Estuary further reduces the meager competitive ability of this declining native plant species.

scholarly journals Release of Dimethylsulfide from Dimethylsulfoniopropionate by Plant-Associated Salt Marsh Fungi

1998 ◽  
Vol 64 (4) ◽  
pp. 1484-1489 ◽  
Author(s):  
M. K. Bacic ◽  
S. Y. Newell ◽  
D. C. Yoch
Keyword(s):  
United States ◽  
Salt Marsh ◽  
Salt Marshes ◽  
Strong Correlation ◽  
The United States ◽  
Smooth Cordgrass ◽  
Secondary Product ◽  
Mitosporic Fungi ◽  
Eukaryotic Algae ◽  
Lyase Activity

ABSTRACT The range of types of microbes with dimethylsulfoniopropionate (DMSP) lyase capability (enzymatic release of dimethylsulfide [DMS] from DMSP) has recently been expanded from bacteria and eukaryotic algae to include fungi (a species of the genus Fusarium[M. K. Bacic and D. C. Yoch, Appl. Environ. Microbiol. 64:106–111, 1998]). Fungi (especially ascomycetes) are the predominant decomposers of shoots of smooth cordgrass, the principal grass of Atlantic salt marshes of the United States. Since the high rates of release of DMS from smooth cordgrass marshes have a temporal peak that coincides with peak shoot death, we hypothesized that cordgrass fungi were involved in this DMS release. We tested seven species of the known smooth cordgrass ascomycetes and discovered that six of them exhibited DMSP lyase activity. We also tested two species of ascomycetes from other DMSP-containing plants, and both were DMSP lyase competent. For comparison, we tested 11 species of ascomycetes and mitosporic fungi from halophytes that do not contain DMSP; of these 11, only 3 were positive for DMSP lyase. A third group tested, marine oomycotes (four species of the genera Halophytophthora andPythium, mostly from mangroves), showed no DMSP lyase activity. Two of the strains of fungi found to be positive for DMSP lyase also exhibited uptake of DMS, an apparently rare combination of capabilities. In conclusion, a strong correlation exists between a fungal decomposer’s ability to catabolize DMSP via the DMSP lyase pathway and the host plant’s production of DMSP as a secondary product.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
United States ◽  
Salt Marsh ◽  
Marine Fish ◽  
Salt Marshes ◽  
Coastal Wetlands ◽  
Life Histories ◽  
Coastal Wetland ◽  
Fish Habitat ◽  
Northeastern United States ◽  
Fishery Habitat

<em>Abstract</em> .—The importance of coastal wetlands to a large number of commercially important marine fish species for spawning, nursery, and foraging habitat is a commonly held belief. Few studies to substantiate this belief have been conducted in the northeastern United States. This paper examines in detail the life histories and habitat requirements of three species of fish commonly found in salt marshes in the northeastern United States. The results indicate that valuable commercial and recreational species of fish and their prey require coastal wetlands as habitat during their life cycles in New England. Coastal wetland restoration projects will increase the abundance of wetland habitat types required by commercial and recreational species of marine fish. The restoration of the salt marsh within the Galilee Bird Sanctuary in Narragansett, Rhode Island is used as case study. When enhancement of fishery habitat value is a goal of a restoration project, the project should incorporate certain design features. However, the designers of many salt-marsh restoration projects assume that reestablishment of salt-marsh vegetation will result in recolonization by other species of animals.

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