flat) and above the tidal prism (on the salt marsh) in the northern part of the Wadden Sea area.
The aims of this study are to elucidate tidal and meteorological induced variations in nutrient (both dissolved and particulate bound) behaviour. This is carried out below the tidal prism (in a tidal channel), in the tidal prism (on an intertidal
Iron sulfide minerals may be formed in tidalmarshes following microbial reduction of sulfate to sulfide. Sulfate reduction requires certain necessary factors including sulfate reducing bacteria, organic matter, low redox potential, and sulfate
. The role of each factor is reviewed critically in this paper and a generalized model is presented to assist interpretation of observed behaviour in marsh soils.
Sulphate reduction as a geomorphological agent in tidalmarshes (Great Marshes at Barnstable, Cape Cod, USA)
Brackish environment ; Coastal environment ; Environmental degradation ; Hydrochemistry ; Intertidal zone ; Massachusetts ; Model ; Salinity ; Tidalmarsh ; United States of America ; Vegetation ; Water temperature
Many tidalmarsh surfaces feature water-filled depressions, known as salt pans (shallow) or ponds (deeper). In the Great Marshes at Barnstable, Cape Cod, pond formation is an active process. The AA. hypothesize that degradation of organic matter
by sulphate-reducing bacteria in these peat-rich marsh deposits is the primary cause of pan and pond formation. Computer simulation suggests that ponds with similar characteristics to those in the Barnstable marshes may develop by sulphate reduction.
Characterization and classification of tidalmarsh soils and plant communities in north-west Spain
The objective of this research is the characterization and classification of soils and plant communities in a tidalmarsh in the Ria of Betanzos (43o21'N, 8o13'W) as a contribution to the knowledge of the specific properties of these soils which
Hydrodynamics of salt marsh creek systems : implications for marsh morphological development and material exchange
Coastal environment ; Earth surface processes ; Geomorphogenesis ; Hydrodynamics ; Norfolk ; Salt marsh ; Sediment transport ; Sedimentary ; Tide ; United Kingdom
In this study, the processes of marsh morphological development are analysed. In north Norfolk, highly unsteady creek flows exhibit well-developed velocity and stress transients which result from the nature of tidal priom and the interaction
of shallow water tidal inputs with hydraulically rough vegetated surfaces (d'après l'Ed.).
Trends of soil organic matter turnover in the salt marsh of the Yangtze River estuary
China ; Estuary ; Geochemistry ; Grain size distribution ; Humid environment ; Isotope analysis ; Organic materials ; Salt marsh
Characteristics and tidal flat trends of soil organic matter (SOM) turnover were studied for the Chrongmingdongtan Salt Marsh in the Yangtze River estuary, based on analyses C 13, grain sizes and contents of particulate organic carbon, total
nitrogen and inorganic carbon for 3 cores excavated from high tidal flat, middle tidal flat and bare flat. The muddy tidal flat processes exerted direct influences on sequestration and turnover of SOM in the salt marsh, and had great constraints
on the spatial and temporal characteristics of SOM turnover of the Chrongmingdongtan Salt Marsh in the Yangtze River estuary.
Late Holocene δ13C and pollen records of paleosalinity from tidalmarshes in the San Francisco Bay estuary, California
California ; Carbon ; Estuary ; Holocene ; Isotope analysis ; Palaeo-environment ; Palynology ; Pollen diagram ; San Francisco ; Sedimentology ; Tidalmarsh ; United States of America
Records of stable carbon isotopes (δ13C) are presented from cores collected from 4 San Francisco Bay marshes and used as a proxy for changes in estuary salinity. The 4 marshes included in this study are located along a natural salinity gradients
that exists in the San Francisco Bay, and records of vegetation change at all 4 sites can be used to infer changes in overall estuary paleosalinity. The δ13C values complement pollen data from the same marsh sites producing a paleoclimate record for the late
Marsh loss in Nanticoke estuary, Chesapeake Bay in Thematic Issue II.
Marsh loss in the Nanticoke estuary dates from the 1920 s. Since 1938 overall rate of loss has averaged 49.6 ha annually, with rates increasing down estuary. Most losses have occurred in submerged upland marshes| tidal freshwater marshes are stable
. Interior ponding has been the primary mechanism of loss. Rising water levels are postulated to be the underlying force behind marsh losses in this estuary.
Hydrology of some tidal channels in estuarine marshland near San Francisco
California ; Channel geometry ; Estuary ; Fluvial hydrology ; Humid environment ; Intertidal zone ; Suspended load ; Tidalmarsh ; United States
Wishing to understand better the role of channels of different sizes in the development and maintenance of marsh lands, a study was made of one major channel and some of its minor tributaries. Measurements of velocity, depth, discharge, and slope
were simultaneously made at ten gages along a natural estuarine channel 19,000 feet in length in Petaluma Marsh, California.
Discordant 14C ages from buried tidal-marsh soils in the Cascadia subduction zone, southern Oregon coast
Peaty, tidal-marsh soils interbedded with estuarine mud in late Holocene stratigraphic sequences near Coos Bay, Oregon, may have been submerged and buried during great (M>8) subduction earthquakes, smaller localized earthquakes, or by nontectonic
Evolution of salt-marsh cliffs in muddy and sandy systems : a qualitative comparison of british west-coast estuaries
Salt-marsh cliffs in the muddy Severn Estuary are mostly strong and tall. They are retreating in response to the erosive attack of wave and tidal currents chiefly through toppling failures and rotational slips. In the sandy Solway Firth
and Morecambe Bay systems, marsh cliffs are strong only in their upper parts, where a dense root-mat of marsh grasses binds the sediments. Here cantilever and toppling failures are the main response of the cliffs to tidal and wave erosion. The differences
between the three estuarine systems in the mechanisms of marsh-cliff erosion are partly reflected in the mode of preservation of the cliffs on the restoration of the conditions leading to renewal of marsh growth.
The effect of bidirectional flow on tidal channel planforms
Aerial photography ; Bank erosion ; California ; Channel geometry ; Coastal environment ; Intertidal zone ; Meander ; Model ; Tidal creek ; Tidal current ; Tidalmarsh ; United States of America
Field surveys and aerial photographs were used to characterize the planform of tidal channels at China Camp Marsh in the San Francisco Bay, California. To model the planform evolution, the AA. assume that the topographic curvature of the channel
centreline is a key element driving meander migration. The curvature calculations, combined with data from numerous cross-sections along the tidal channel, were used to parameterize a computer model. With this model, based on recent theoretical work
Tsunami deposits beneath tidalmarshes on northwestern Vancouver Island, British Columbia
British Columbia ; C 14 dating ; Canada ; Earthquake ; Grain size distribution ; Humid environment ; Island ; Isotope analysis ; Sand ; Sedimentology ; Stratigraphy ; Tidalmarsh ; Tsunami ; Vancouver
The aim of this paper is to characterize tsunami deposits in Holocene peat at tidalmarshes on northwestern Vancouver Island. The AA. studied the architecture, stratigraphy, and sedimentology of 2 sand sheets at Fair Harbour, Neroutsos Inlet
Numerical simulation of vertical marsh growth and adjustment to accelerated sea-level rise, North Norfolk, UK
Coastal environment ; Coastal marsh ; England ; Eustatism ; Fauna ; Flood ; Flora ; Global change ; Model ; Numerical model ; Sea level ; Sedimentation ; United Kingdom
This paper outlines the implementation and application of a refined one-dimensional model designed to simulate the vertical adjustment of marsh surfaces to various combinations of sediment supply, tidal levels and regional subsidence
, with particular reference to the marshes of north Norfolk, on the East coast of England.
active uptake conversion, release and recycling of nitrogen within a marsh ecosystem. Nitrogen losses are mainly through tidal exchanges and denitrification, and these two outputs balance the gains. The chemical exchanges among uplands, marshes
Salt marshes reduces oxidised nitrogenous compounds to ammonium and particulate nitrogen and export these reduced forms to coastal waters. The internal demands exceed the net imputs of nitrogen by rain, groundwater flow and fixation, suggesting very
Environmental controls on multiscale spatial patterns of salt marsh vegetation
Coastal environment ; Denmark ; Jylland ; Salinity ; Salt marsh ; Spatial distribution ; Tidal creek ; Topography ; Vegetation
The AA. investigate the topography-vegetation relationship in a Danish salt marsh, focusing upon 2 scales : a macro-scale (ca. 500 m) across the marsh platform, encompasing seaward and landward areas, and a meso-scale (ca. 25 m) across tidal creeks
. While long-term sea-level variation and grazing influenced the macro-scale pattern, short-term fluvial-geomorphic processes drove the meso-scale pattern. The results suggest that, in salt marshes, elevation plays a still more important ecological role
Stratigraphic and microfossil evidence for late Holocene tsunamis at Swantown marsh, Whidbey Island, Washington
Earthquake ; Holocene ; Palaeo-ecology ; Palaeo-environment ; Plate tectonics ; Quaternary ; Sedimentology ; Stratigraphy ; Tidalmarsh ; Tsunami ; United States of America ; Washington State
The AA. report stratigraphic and paleoecologic findings from a tidalmarsh on the west coast of Whidbey Island, Washington, where 4 muddy sand layers were found in the peat underlying the marsh. These sand sheets record repeated inundation
of the marsh over a short time period by distinct pulses of sediment-laden ocean water, consistent with deposition by a tsunami wave train. The layers have been radiocarbon-dated. The 2 older layers do not correlate with plate-boundary events. They may
deposition in tidal creeks, providing large amounts of material that is eventually distributed to and deposited on marsh surfaces.
This research considers acoustic Doppler velocimeter (ADV) and optical backscatter sensor (OBS) data from a sheltered tidal creek in the Minas Basin, for analysis of tidal characteristics in a hypertidal creek environment over spring and neap tidal
cycles. Sediment deposition in the creek was also measured. Results show a first-order control of topography on flow magnitude in the tidal creek, which impacts net sediment deposition through resuspension and removal of newly introduced material