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1

Centuries of Human-Driven Change in Salt Marsh Ecosystems  

NASA Astrophysics Data System (ADS)

Salt marshes are among the most abundant, fertile, and accessible coastal habitats on earth, and they provide more ecosystem services to coastal populations than any other environment. Since the Middle Ages, humans have manipulated salt marshes at a grand scale, altering species composition, distribution, and ecosystem function. Here, we review historic and contemporary human activities in marsh ecosystems—exploitation of plant products; conversion to farmland, salt works, and urban land; introduction of non-native species; alteration of coastal hydrology; and metal and nutrient pollution. Unexpectedly, diverse types of impacts can have a similar consequence, turning salt marsh food webs upside down, dramatically increasing top down control. Of the various impacts, invasive species, runaway consumer effects, and sea level rise represent the greatest threats to salt marsh ecosystems. We conclude that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management.

Gedan, K. Bromberg; Silliman, B. R.; Bertness, M. D.

2009-01-01

2

The nitrogen budget of a salt marsh ecosystem  

Microsoft Academic Search

Salt marshes reduce oxidised nitrogenous compounds to ammonium and paniculate nitrogen and export these reduced forms to coastal waters. The internal demands exceed the net inputs of nitrogen by rain, groundwater flow and fixation, suggesting very active uptake, conversion, release and recycling of nitrogen within a marsh ecosystem. Nitrogen losses are mainly through tidal exchanges and denitrification, and these two

Ivan Valiela; John M. Teal

1979-01-01

3

Salt Marsh--Estuarine Ecosystem: A Liquid Asset  

ERIC Educational Resources Information Center

A comprehensive description of the salt marsh-estuarine ecosystem is provided. Topics discussed include: the general geologic history and formation of this ecosystem; physical and chemical parameters; variety; primary productivity; tidal zones; kind, sizes and abundance of vegetation; and the environmental factors influencing vegetation. (BT)

Steever, E. Zell

1977-01-01

4

Ecosystem engineers activate mycorrhizal mutualism in salt marshes.  

PubMed

Theory predicts that ecosystem engineers should have their most dramatic effects when they enable species, through habitat amelioration, to live in zones where physical and biological conditions would otherwise suppress or limit them. Mutualisms between mycorrhizal fungi and plants are key determinants of productivity and biodiversity in most terrestrial systems, but are thought to be unimportant in wetlands because anoxic sediments exclude fungal symbionts. Our field surveys revealed arbuscular mycorrhizal associations on salt marsh plant roots, but only in the presence of crabs that oxygenate soils as a by-product of burrowing. Field experiments demonstrate that fungal colonization is dependent on crab burrowing and responsible for nearly 35% of plant growth. These results highlight ecosystem engineers as ecological linchpins that can activate and maintain key mutualisms between species. Our findings align salt marshes with other important biogenic habitats whose productivity is reliant on mutualisms between the primary foundation species and micro-organisms. PMID:17845290

Daleo, Pedro; Fanjul, Eugenia; Mendez Casariego, Agustina; Silliman, Brian R; Bertness, Mark D; Iribarne, Oscar

2007-10-01

5

Salt Marsh  

NSDL National Science Digital Library

High school level and higher description of Spartina salt marshes with pictures. Page is full of fantastic photographs most featuring a descriptive caption. Topics discussed include zonation, succession, and the intertidal zone. The habitat's associated flora and fauna are discussed. Organisms of particular interest include: Spartina alterniflora, Spartina patens, Geukenzia demissa, Mytilus edulis, Distichlis spicata, Salicornia, Melampus bidentatus, Ilyanassa obsoleta, and Hydrobia totteni.

6

Fate and effects of nutrients and heavy metals in experimental salt marsh ecosystems  

Microsoft Academic Search

Fate and effects of the macro nutrients nitrogen and phosphorus, and the heavy metals zinc, copper and cadmium, brought into experimental salt marsh ecosystems via sediment supply, were studied over a three-year period.The supply of sediment from the Marsdiep (at a low and high rate) and from the harbour of Delfzijl (at a high rate) led to an increase of

Peter C. Leendertse; Martin C. Th. Scholten; Jan Tjalling van der Wal

1996-01-01

7

Effects of the antifouling compound, Irgarol 1051, on a simulated estuarine salt marsh ecosystem.  

PubMed

Toxicity effects of the antifouling compound, Irgarol 1051, were examined using a simulated estuarine salt marsh ecosystem. The 35 day mesocosm exposure incorporated tidal flux and contained seawater, sediments, marsh grass, and estuarine biota. Irgarol (10.0 microg/l) caused a significant reduction in phytoplankton biomass and primary productivity. HPLC pigment analysis indicated significant effects of irgarol on both phytoplankton and periphyton community composition, with decreased concentrations of pigments representative of diatom species. There was also a significant decrease in dissolved oxygen levels in the 10.0 microg/l irgarol treatment. Growth of the hard shell clam was significantly reduced in the 1.0 and 10.0 microg/l irgarol treatments. The effects observed occurred at irgarol concentrations greater than those typically measured in the environment. Prolonged exposure, the accumulation of irgarol in sediments, plant, or animal tissues, and the interaction of irgarol with other chemicals in the environment; however, could increase risk. PMID:19015980

DeLorenzo, M E; Pennington, P L; Chung, K W; Finnegan, M C; Fulton, M H

2008-11-18

8

Ecosystem assembly rules: the interplay of green and brown webs during salt marsh succession.  

PubMed

Current theories about vegetation succession and food web assembly are poorly compatible, as food webs are generally viewed to be static, and succession is usually analyzed without the inclusion of higher trophic levels. In this study we present results from a detailed analysis of ecosystem assembly rules over a chronosequence of 100 years of salt marsh succession. First, using 13 yearlong observations on vegetation and soil parameters in different successional stages, we show that the space-for-time substitution is valid for this chronosequence. We then quantify biomass changes for all dominant invertebrate and vertebrate species across all main trophic groups of plants and animals. All invertebrate and vertebrate species were assigned to a trophic group according to feeding preference, and changes in trophic group abundance were quantified for seven different successional stages of the ecosystem. We found changes from a marine-fueled, decomposer-based (brown) food web in early stages to a more terrestrial, plant-based, herbivore-driven (green) food web in intermediate succession stages, and finally to a decomposer-based, terrestrial-driven food web in the latest stages. These changes were accompanied not only by an increase in live plant biomass and a leveling toward late succession but also by a constant increase in the amount of dead plant biomass over succession. Our results show that the structure and dynamics of salt marsh food webs cannot be understood except in light of vegetation succession, and vice versa. PMID:23236907

Schrama, Maarten; Berg, Matty P; Olff, Han

2012-11-01

9

Experimental restoration of a salt marsh with some comments on ecological restoration of coastal vegetated ecosystems in Korea  

NASA Astrophysics Data System (ADS)

Since the 1980s, the coastal wetlands in Korea have been rapidly degraded and destroyed mainly due to reclamation and landfills for coastal development. In order to recover damaged coastal environments and to develop wetland restoration technologies, a 4-year study on ecological the restoration of coastal vegetated ecosystems was started in 1998. As one of a series of studies, a small-scale experiment on salt marsh restoration was carried out from April 2000 to August 2001. The experiment was designed to find effective means of ecological restoration through a comparison of the changes in environmental components and species structure between two different experimental plots created using sediment fences, one with and one without small canals. Temporal variation in surface elevation, sedimentary facies, and benthic species were measured seasonally in each plot and in the adjacent natural reference sites. Monthly exposure occurred from 330 cm to mean sea level, which represents the critical tidal level (CTL) at which salt marsh plants colonize. Vegetation, especially Suaeda japonica, colonized the site the following spring and recovered to a similar extent in the natural marshes 16 months later. The sedimentary results indicated that the sediment fences had effects on particle size and sediment accumulation, especially in the plot with small canals. This experiment also showed that tidal height, especially that exceeding the CTL, is an important factor in the recovery of the benthic fauna of salt marshes. From these results, we suggested that designs for the restoration of salt marsh ecosystems must consider the inclusion of a tidal height exceeding CTL, as this may allow reconstruction of the previous natural ecosystem without artificial transplanting.

Koo, Bon Joo; Je, Jong Geel; Woo, Han Jun

2011-03-01

10

Deteriorating Coastal Salt Marshes - Lessons Learned  

EPA Science Inventory

Noticeable changes in structure and function in some Narragansett Bay, RI and Jamaica Bay, NY coastal salt marshes support the idea that â??tipping pointsâ? in these ecosystems have been exceeded....

11

New Salt Marshes for Old - Salt Marsh Creation and Management  

Microsoft Academic Search

Salt marshes are vulnerable to rising sea levels, coastal developments, pollution and disturbance, and at the same time they provide economic, social and environmental benefits. Recently salt marsh re-creation has been undertaken in the interest of both sea defence and nature conservation. The vegetation pattern on these newly created marshes is very different from that found on mature marshes. This

L. Boorman; J. Hazelden; M. Boorman

2002-01-01

12

Responses of salt marsh ecosystems to mosquito control management practices along the Atlantic Coast (U.S.A.)  

USGS Publications Warehouse

Open marsh water management (OMWM) of salt marshes modifies grid-ditched marshes by creating permanent ponds and radial ditches in the high marsh that reduce mosquito production and enhance fish predation on mosquitoes. It is preferable to using pesticides to control salt marsh mosquito production and is commonly presented as a restoration or habitat enhancement tool for grid-ditched salt marshes. Monitoring of nekton, vegetation, groundwater level, soil salinity, and bird communities before and after OMWM at 11 (six treatment and five reference sites) Atlantic Coast (U.S.A.) salt marshes revealed high variability within and among differing OMWM techniques (ditch-plugging, reengineering of sill ditches, and the creation of ponds and radial ditches). At three marshes, the dominant nekton shifted from fish (primarily Fundulidae species) to shrimp (Palaemonidae species) after manipulations and shrimp density increased at other treatment sites. Vegetation changed at only two sites, one with construction equipment impacts (not desired) and one with a decrease in woody vegetation along existing ditches (desired). One marsh had lower groundwater level and soil salinity, and bird use, although variable, was often unrelated to OMWM manipulations. The potential effects of OMWM manipulations on non-target salt marsh resources need to be carefully considered by resource planners when managing marshes for mosquito control.

James-Pirri, Mary-Jane; Erwin, R. Michael; Prosser, Diann J.; Taylor, Janith D.

2012-01-01

13

Mercury cycling and sequestration in salt marshes sediments: an ecosystem service provided by Juncus maritimus and Scirpus maritimus.  

PubMed

In this study two time scales were looked at: a yearlong study was completed, and a 180-day decay experiment was done. Juncus maritimus and Scirpus maritimus have different life cycles, and this seems to have implications in the Hg-contaminated salt marsh sediment chemical environment, namely Eh and pH. In addition, the belowground biomass decomposition rates were faster for J. maritimus, as well as the biomass turnover rates. Results show that all these species-specific factors have implications in the mercury dynamics and sequestration. Meaning that J. maritimus belowground biomass has a sequestration capacity for mercury per square metre approximately 4-5 times higher than S. maritimus, i.e., in S. maritimus colonized areas Hg is more extensively exchange between belowground biomass and the rhizosediment. In conclusion, J. maritimus seems to provide a comparatively higher ecosystem service through phytostabilization (Hg complexation in the rhizosediment) and through phytoaccumulation (Hg sequestration in the belowground biomass). PMID:21514707

Marques, B; Lillebø, A I; Pereira, E; Duarte, A C

2011-04-22

14

A laboratory study on biochemical degradation and microbial utilization of organic matter comprising a marine diatom, land grass, and salt marsh plant in estuarine ecosystems  

Microsoft Academic Search

We studied the biochemical degradation of organic matter comprising marine diatom, land grass, and salt marsh plant in estuarine\\u000a ecosystems in two laboratory microcosms consisting of estuarine sediments and coastal seawater. The materials were incubated\\u000a separately and together under controlled oxic and anoxic conditions to test effects of co-metabolism and redox on overall\\u000a degradation of organic matter. We followed variations

Jihong Dai; Ming-Yi Sun; Randolph A. Culp; John E. Noakes

2009-01-01

15

Guidelines for the Bioremediation of Oil-Contaminated Salt Marshes.  

National Technical Information Service (NTIS)

Salt marshes are among the most sensitive ecosystems and, therefore, the most difficult to clean. Applications of some traditional oil spill cleanup techniques in wetland habitats have caused more damage than the oil itself. The objective of this document...

X. Zhu A. D. Venosa M. T. Suidan K. Lee

2004-01-01

16

Relationships between Sediment Microbial Communities and Pollutants in Two California Salt Marshes  

Microsoft Academic Search

Salt marshes are important ecosystems whose plant and microbial communities can alter terrestrially derived pollutants prior to coastal water discharge. However, knowledge regarding relationships between anthropogenic pollutant levels and salt marsh microbial communities is limited, and salt marshes on the West Coast of the United States are rarely examined. In this study, we investigated the relationships between microbial community composition

Y. Cao; G. N. Cherr; A. L. Córdova-Kreylos; T. W.-M. Fan; P. G. Green; R. M. Higashi; M. G. LaMontagne; K. M. Scow; C. A. Vines; J. Yuan; P. A. Holden

2006-01-01

17

What do we need to assess the sustainability of the tidal salt marsh carbon sink?  

Microsoft Academic Search

Tidal salt marshes provide a range of ecosystem services. The most recently recognized is their provision of highly effective sinks for atmospheric carbon dioxide, a characteristic they share with mangroves swamps which largely replace salt marshes in the intertidal zones of tropical regions. Efforts are emerging to use salt marsh preservation or restoration in carbon offset programs, similar to the

Gail L. Chmura

18

Plant Zonation in a Salt Marsh.  

ERIC Educational Resources Information Center

|The zonation of plants within a salt marsh environment is detailed via illustrations and scientific nomeclature for purposes of encouraging outdoor educators to use the salt marsh environment as a learning laboratory. (JC)|

Etri, Lawrence R.

1978-01-01

19

Coastal eutrophication as a driver of salt marsh loss.  

PubMed

Salt marshes are highly productive coastal wetlands that provide important ecosystem services such as storm protection for coastal cities, nutrient removal and carbon sequestration. Despite protective measures, however, worldwide losses of these ecosystems have accelerated in recent decades. Here we present data from a nine-year whole-ecosystem nutrient-enrichment experiment. Our study demonstrates that nutrient enrichment, a global problem for coastal ecosystems, can be a driver of salt marsh loss. We show that nutrient levels commonly associated with coastal eutrophication increased above-ground leaf biomass, decreased the dense, below-ground biomass of bank-stabilizing roots, and increased microbial decomposition of organic matter. Alterations in these key ecosystem properties reduced geomorphic stability, resulting in creek-bank collapse with significant areas of creek-bank marsh converted to unvegetated mud. This pattern of marsh loss parallels observations for anthropogenically nutrient-enriched marshes worldwide, with creek-edge and bay-edge marsh evolving into mudflats and wider creeks. Our work suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects. Projected increases in nitrogen flux to the coast, related to increased fertilizer use required to feed an expanding human population, may rapidly result in a coastal landscape with less marsh, which would reduce the capacity of coastal regions to provide important ecological and economic services. PMID:23075989

Deegan, Linda A; Johnson, David Samuel; Warren, R Scott; Peterson, Bruce J; Fleeger, John W; Fagherazzi, Sergio; Wollheim, Wilfred M

2012-10-18

20

Salt marshes and eutrophication: An unsustainable outcome  

Microsoft Academic Search

Most plant production by emergent coastal marshes occurs belowground. This belowground production adds to the accumulation of organic matter sustaining salt marshes as sea level rises, thus preventing excessive flooding, eventual plant death, and habitat loss. The ubiquitous nutrient enrichment of coastal salt marshes stimulating aboveground plant growth may result in higher rates of inorganic matter accumulation that compensates for

R. Eugene Turner; Brian L. Howes; John M. Teal; Charles S. Milan; Erick M. Swenson; Dale D. Goehringer-Tonerb

2009-01-01

21

Hydrologic modeling as a predictive basis for ecological restoration of salt marshes  

Microsoft Academic Search

Roads, bridges, causeways, impoundments, and dikes in the coastal zone often restrict tidal flow to salt marsh ecosystems. A dike with tide control structures, located at the mouth of the Herring River salt marsh estuarine system (Wellfleet, Massachusetts) since 1908, has effectively restricted tidal exchange, causing changes in marsh vegetation composition, degraded water quality, and reduced abundance of fish and

Charles T. Roman; Richard W. Garvine; John W. Portnoy

1995-01-01

22

Respiration Studies in a Louisiana Salt Marsh.  

National Technical Information Service (NTIS)

Respiration studies of the salt marsh intertidal zone and adjacent submerged sediments were carried out in coastal Louisiana from July 1973 to August 1974. Respiration of the marsh intertidal zone was measured by dissolved oxygen uptake in an enclosure ov...

C. S. Hopkinson J. W. Day B. T. Gael

1978-01-01

23

Persistence and movement of atrazine in a salt marsh sediment microecosystem  

SciTech Connect

Pesticides enter salt marshes in runoff from agricultural lands or through direct or near-by application. Concern has been raised that the tidal action in the salt marsh that functions to trap sediment and nutrients may also function to concentrate pesticides to harmful levels. Studies have been conducted to evaluate the effect of pesticides on representative species of salt marsh ecosystems. This paper describes the use of a modified salt marsh microecosystem to evaluate persistence and movement of atrazine in salt marsh sediment under simulated tidal flux and continuous flooding conditions. Atrazine persistence was also compared under normal field conditions.

Isensee, A.R.

1987-09-01

24

Atrazine Fate and Effects in a Salt Marsh.  

National Technical Information Service (NTIS)

Components of the Spartina alterniflora salt marsh were exposed to atrazine individually, in microecosystems, and in the field, to determine its effects on salt marsh components and its fate in the salt marsh. Components studied were S. alterniflora; hors...

D. E. Davis J. D. Weete C. G. P. Pillai F. G. Plumley J. T. McEnerney

1979-01-01

25

The dynamics of bottom–up and top–down control in a New England salt marsh  

Microsoft Academic Search

Traditionally, salt marsh ecosystems were thought to be controlled exclusively by bottomup processes. Recently, this paradigm has shifted to include topdown control as an additional primary factor regulating salt-marsh community structure. The most recent research on consumer impacts in southern US marshes has shown that topdown forces often interact with biotic and abiotic factors, such as secondary fungal infection in

N. M. Sala; M. D. Bertness; B. R. Silliman

2008-01-01

26

Making and Measuring a Model of a Salt Marsh  

NSDL National Science Digital Library

Students are often confused by the difference between the terms accuracy and precision . In the following activities, students explore the definitions of accuracy and precision while learning about salt march ecology and the methods used by scientists to assess salt marsh health. The activities also address the concept that the ocean supports a great diversity of life and ecosystems, which is one of the ocean literacy principles outlined by the Ocean Literacy Network.

Curran, Mary C.; Fogleman, Tara

2007-12-01

27

Ecogeomorphic Properties of Flood-ebb Flows on a Coastal North Carolina Salt-marsh Platform  

Microsoft Academic Search

Salt marsh ecosystems play a vital role in nutrient processing, shoreline defense, and as habitats for commercially important species. Along the Albemarle and Pamlico Sounds, North Carolina, where the tidal amplitude ranges from 1.0 to 1.5 m, salt marsh communities are expected to undergo a transition from intertidal marshes to subtidal habitats in response to sea-level rise and associated increases

S. Howell; D. Furbish; S. Mudd

2006-01-01

28

Hydrologic modeling as a predictive basis for ecological restoration of salt marshes  

Microsoft Academic Search

Roads, bridges, causeways, impoundments, and dikes in the coastal zone often restrict tidal flow to salt marsh ecosystems.\\u000a A dike with tide control structures, located at the mouth of the Herring River salt marsh estuarine system (Wellfleet, Massachusetts)\\u000a since 1908, has effectively restricted tidal exchange, causing changes in marsh vegetation composition, degraded water quality,\\u000a and reduced abundance of fish and

Charles T. Roman; Richard W. Garvine; John W. Portnoy

1995-01-01

29

What's the Use of a Salt Marsh?  

ERIC Educational Resources Information Center

|Summarizes information about salt marshes, including descriptions of their development and structure, details of their values in terms of commercial fishing, stabilization of coastal zones, "reclamation" for grazing and cropfields, recreation and aesthetics. (CS)|

Van Raalte, Charlene

1977-01-01

30

Shore Erosion Control with Salt Marsh Vegetation.  

National Technical Information Service (NTIS)

Salt marsh plants are effective in stabilizing eroding shorelines in many sheltered coastal areas. Exceptional results have been achieved in a variety of intertidal environments at a fraction of the cost required for comparable structural protection. Tech...

P. L. Knutson M. R. Inskeep

1982-01-01

31

Mobile dunes and eroding salt marshes  

NASA Astrophysics Data System (ADS)

The paper deals with general outlines of salt marsh and dune vegetation in the Ellenbogen and Listland area on Sylt (Schleswig-Holstein, FRG). The composition of current salt marsh vegetation is considered to be mainly the result of a long-lasting process of tidal inundation, grazing, and a permanent influence of groundwater seepage from the surrounding dunes. The lower salt marsh communities have shown constancy for 67 years, due to the effect of heavy grazing. The mid-upper salt marsh communities demonstrated a succession from a Puccinellia maritima-dominated community of the lower marsh to a Juncus gerardii-dominated community of the mid-upper salt marsh, which may be due to the transport of sand — over a short time — on the surface of the marsh. The area covered by plant communities of annuals below Mean High Water (MHW) seemed to diminish. Salt marsh soils, especially of the mid-upper marsh, indicate sandy layers resulting from sand drift of the dunes. Dry and wet successional series of the dunes in the Listland/Ellenbogen area both show grassy stages shifting to dwarf shrubs as final stages. White primary dunes can only be found on the accreting shoreline of the Ellenbogen, which is also grazed by sheep; vegetation cover therefore remains dominated by grasses, mosses and lichens. Three mobile dunes (as the most prominent features of this landscape) have been left unaffected by seeding and planting by local authorities. Grazing is considered to be an inadequate tool in nature conservation as long as natural processes are to prevail in the landscape as major determinants.

Neuhaus, R.

1994-06-01

32

Coastal Wetland Deterioration, Climate Change and Nutrient Inputs in California and Southern New England Salt Marsh  

EPA Science Inventory

Coastal salt marshes provide a wide variety of ecosystem services, including habitat for protected vertebrates and ecologically valuable invertebrate fauna, flood protection, and improvements in water quality for adjacent marine and estuarine environments. Here, we consider the i...

33

Mercury volatilization from salt marsh sediments  

Microsoft Academic Search

In situ volatilization fluxes of gaseous elemental mercury, Hg(0), were estimated for tidally exposed salt marsh sediments in the summer at the urban\\/industrial Secaucus High School Marsh, New Jersey Meadowlands (Secaucus, New Jersey) and in the early autumn at a regional background site in the Great Bay estuary (Tuckerton, New Jersey). Estimated daytime sediment-air mercury volatilization fluxes at the Secaucus

Lora M. Smith; John R. Reinfelder

2009-01-01

34

Habitat Function of a Restored Salt Marsh: Post-Larval Gulf Killifish as a Sentinel  

EPA Science Inventory

Successful marsh restoration requires recreating conditions to ensure proper ecosystem function. One approach to monitor restoration success is using a sentinel species as a proxy integrator of salt marsh function. The gulf killifish (Fundulus grandis, Baird and Girard) is a goo...

35

Mercury volatilization from salt marsh sediments  

NASA Astrophysics Data System (ADS)

In situ volatilization fluxes of gaseous elemental mercury, Hg(0), were estimated for tidally exposed salt marsh sediments in the summer at the urban/industrial Secaucus High School Marsh, New Jersey Meadowlands (Secaucus, New Jersey) and in the early autumn at a regional background site in the Great Bay estuary (Tuckerton, New Jersey). Estimated daytime sediment-air mercury volatilization fluxes at the Secaucus High School Marsh ranged from -375 to +677 ng m-2 h-1 and were positive (land to air flux) in 16 out of 20 measurement events. At the Great Bay estuary, mercury fluxes measured continuously over a 48-h period ranged from -34 to +81 ng m-2 h-1 and were positive during the day and negative at night. At both sites, mercury volatilization fluxes peaked at midday, and cumulative mercury fluxes exhibited strong positive correlations with cumulative solar radiation (r2 = 0.97, p < 0.01) consistent with a light-driven mercury volatilization efficiency of about 15 ng Hg mol PAR-1 or about 0.06 ng Hg kJ-1. No significant correlations were found between mercury fluxes and wind speed, air temperature, or tide height at either site. Thus despite a tenfold difference in sediment mercury concentration, photochemistry appears to be the dominant factor controlling mercury volatilization from these salt marsh sediments. The average mercury volatilization flux estimated for the Great Bay salt marsh in this study (17 ng m-2 h-1) compares well with other micrometeorological mercury fluxes for nonpoint source contaminated salt marsh and forest soils (8-18 ng m-2 h-1) and is more than 10 times higher than the average mercury emission flux from land (˜1 ng m-2 h-1). Annual mercury emissions from salt marsh wetlands may be comparable to individual industrial emissions sources in coastal states of the eastern United States.

Smith, Lora M.; Reinfelder, John R.

2009-06-01

36

Effects of pH and plant sourceon lignocellulose biodegradation rates in two wetland ecosystems, the Okefenokee Swamp and a Georgia salt marsh  

Microsoft Academic Search

The microbial mineralization of synthetic ( L4C)lignin, specifically radiolabeled ( 14C-ligninl-lig- nocellulose and ( L4C-polysaccharide)-lignocellulose from a variety of aquatic herbaceous and woody plants was investigated in water and sediment from a salt marsh on Sapelo Island, Georgia, and from the Okefenokee Swamp, an acidic peat-forming freshwater swamp in southern Georgia. Rates of microbial degradation of lignocellulose were depressed in

RONALD BENNER; MARY ANN MORAN; ROBERT E. HODSON

1985-01-01

37

Gross production exceeds gross consumption of methyl halides in northern California salt marshes  

NASA Astrophysics Data System (ADS)

Coastal salt marshes are sources of CH3Br and CH3Cl to the atmosphere, but the wide range of reported emission rates illustrates the need to understand better the factors controlling net fluxes. Here we demonstrate the use of a stable isotope tracer method to separately evaluate gross production and consumption fluxes to determine their relative roles in the overall net flux. At two salt marshes in northern California, gross production exceeds gross consumption at all measured sites, leading to a large net source overall. Emission rates are within the range observed at other temperate salt marshes. By evaluating the consumption component separately, we explain how a typical salt marsh source might convert into a temporary net sink by exposing the ecosystem to uncharacteristically high concentrations of methyl halides. This circumstance may account for the reported net uptake of methyl chloride during the growing season at a coastal salt marsh in China.

Rhew, Robert; Mazéas, Olivier

2010-09-01

38

Modeling wave impact on salt marsh boundaries  

NASA Astrophysics Data System (ADS)

Wind-wave attack is the fundamental cause of erosion of salt marsh boundaries. Tidal forcing acts as a proxy determining at which elevation waves pound against the marsh edge and conditioning the propagation and transformation of wave trains as they move toward these boundaries. The objective of the present work is to evaluate, through analysis of the results of a numerical model, the effect of wave action on marsh boundaries as a function of tidal elevation and wave height for different edge configurations. In order to link numerical simulations to field conditions, the model inputs are based on topographical and hydrodynamical surveys conducted at a study site at the Virginia Coast Reserve (VCR), VA. Model results show that the wave thrust on the marsh scarp strongly depends on tidal level. The thrust increases with tidal elevation until the marsh is submerged and then rapidly decreases. The wave thrust is maximum for a vertical scarp and minimum for a terraced scarp. Similarly, wave energy dissipation is maximized just above the marsh platform elevation, when wave reflection is reduced and wave breaking occurs at the marsh edge.

Tonelli, Mara; Fagherazzi, Sergio; Petti, Marco

2010-09-01

39

Tidal regime, salinity and salt marsh plant zonation  

Microsoft Academic Search

Salt marsh morphology is known to be strongly correlated to vegetation patterns through a complex interplay of biological and physical processes. This paper presents the results of field surveys at several study salt marshes within the Venice Lagoon (Italy), which indicate that salt-marsh macrophyte species may indeed be associated with narrow ranges of soil topographic elevation. Statistical analyses show that

Sonia Silvestri; Andrea Defina; Marco Marani

2004-01-01

40

Tidal regime, salinity and salt marsh plant zonation  

Microsoft Academic Search

Salt marsh morphology is known to be strongly correlated to vegetation patterns through a complex interplay of biological and physical processes. This paper presents the results of field surveys at several study salt marshes within the Venice Lagoon (Italy), which indicate that salt-marsh macrophyte species may indeed be associated with narrow ranges of soil topographic elevation. Statistical analyses show that

Sonia Silvestri; Andrea Defina; Marco Marani

2005-01-01

41

Early Salt-Marsh Development, an Example of a Turing Instability?  

NASA Astrophysics Data System (ADS)

In the past decades, regular spatial patterns have been described in a wide range of ecosystems, ranging from arid lands to boreal peat lands. Pattern formation mechanisms in many of these ecosystems are caused by scale-dependent interactions between organisms and geophysical processes, causing facilitation between organisms at small spatial scale, but inhibition at larger spatial scales. This conforms to the activation-inhibition principle laid out by Alan Turing in 1953. We present a combination of experimental and modeling studies on early salt-marsh development that indicate that similar scale-dependent interactions determine the establishment of salt-marsh vegetation and early geomorphological development of the marsh. Based on these studies, we argue that the early development of salt-marsh ecosystems is characterized by a Turing instability, placed into a complex landscape setting.

van de Koppel, J.

2008-12-01

42

An analytical biogeomorphic model for salt-marsh equilibrium states and transient dynamics  

NASA Astrophysics Data System (ADS)

Salt marshes are coastal ecosystems of great relevance characterized by extremely high biodiversity and primary productivity, and are agreed to be important indicators of environmental change. The overall dynamics of such systems are governed by complex two-way interactions between biological and geomorphological processes, their evolution and possible survival depending on complex biogeomorphic feedbacks. Observations of marsh degradation worldwide and the acceleration in the rate of global sea level rise highlight the importance of improving our understanding of the chief processes controlling salt-marsh response to current natural climate changes and to the effects of changes in sediment supply, usually associated with human interference. To address this important issue we have developed the first analytical model describing the biomorphodynamic evolution of salt-marsh ecosystems in the vertical plane. The model allows one to study salt-marsh equilibria and dynamics in response to changes in sediment load, organic soil production, and rates of relative sea level rise. Our results show that in the case of a step change in the rate of relative sea level rise or in the availability of sediment, the time required by the marsh platform to reach new equilibrium conditions depends on the initial and final sediment availability, on vegetation productivity, on the tidal range, and on the initial and newly imposed rate of sea level rise. Marshes are more resilient to a decrease rather than to an increase in the rate of relative sea level rise, whereas they are more resilient to a decrease rather than to an increase in sediment availability. Despite the model is based on a few simplifying assumptions it provides a coupled description of the key biogeomorphic processes governing the vertical evolution of salt-marsh ecosystems and allows an instant assessment of key dynamical behaviour of salt-marsh surfaces. Model results are consistent with field observations and with he results of previous numerical models, and furthermore provide means to improve our understanding of salt-marsh biomorphodynamics.

D'Alpaos, A.; Mudd, S. M.; Carniello, L.

2011-12-01

43

Salt Marsh Planting: Example Contract Specifications.  

National Technical Information Service (NTIS)

This technical note provides an example set of contract specifications that can be used as a template by Corps personnel for planting salt marsh vegetation. While the example presented here will be useful to U.S. Army Corps of Engineers biologists, engine...

Schneider B. Streever R. Medina

2000-01-01

44

Salt tolerance of salt marsh plants of Otago, New Zealand  

Microsoft Academic Search

The salt tolerance of 31 species — 29 halophytes constituting a large proportion of the more important species in salt marshes of Otago, and 2 glycophytes — was examined in water culture. The effects of salinity on growth and survival were the main parameters measured. There were considerable differences between species; most could not grow in sea water (3.5% NaCl),

T. R. Partridge; J. B. Wilson

1987-01-01

45

A trophic cascade regulates salt marsh primary production  

PubMed Central

Nutrient supply is widely thought to regulate primary production of many ecosystems including salt marshes. However, experimental manipulation of the dominant marsh grazer (the periwinkle, Littoraria irrorata) and its consumers (e.g., blue crabs, Callinectes sapidus, terrapins, Malaclemys terrapin) demonstrates plant biomass and production are largely controlled by grazers and their predators. Periwinkle grazing can convert one of the most productive grasslands in the world into a barren mudflat within 8 months. Marine predators regulate the abundance of this plant-grazing snail. Thus, top-down control of grazer density is a key regulatory determinant of marsh grass growth. The discovery of this simple trophic cascade implies that over-harvesting of snail predators (e.g., blue crabs) may be an important factor contributing to the massive die-off (tens of km2) of salt marshes across the southeastern United States. In addition, our results contribute to a growing body of evidence indicating widespread, predator regulation of marine macrophyte production via trophic cascades (kelps, seagrasses, intertidal algae).

Silliman, Brian Reed; Bertness, Mark D.

2002-01-01

46

Pregermination Requirements and Establishment Techniques for Salt Marsh Plants.  

National Technical Information Service (NTIS)

Pregermination requirements and establishment techniques for several salt marsh plant species are discussed. Both seeding and transplanting have resulted in successful artificial marsh establishment on natural coastal areas and on deposited dredged materi...

P. K. Falco F. J. Cali

1977-01-01

47

Regional ontogeny of new England salt marsh die-off.  

PubMed

Coastal areas are among the world's most productive and highly affected ecosystems. Centuries of human activity on coastlines have led to overexploitation of marine predators, which in turn has led to cascading ecosystem-level effects. Human effects and approaches to mediating them, however, differ regionally due to gradients in biotic and abiotic factors. Salt marsh die-off on Cape Cod, Massachusetts (U.S.A.), triggered by a recreational-fishing-induced trophic cascade that has released herbivorous crabs from predator control, has been ongoing since 1976. Similar salt marsh die-offs have been reported in Long Island Sound and Narragansett Bay (U.S.A.), but the driving mechanism of these die-offs has not been examined. We used field experiments to assess trophic interactions and historical reconstructions of 24 New England marshes to test the hypotheses that recreational fishing and predator depletion are a regional trigger of salt marsh die-off in New England and that die-offs in Long Island Sound and Narragansett Bay are more recent than those on Cape Cod. Predator depletion was the general trigger of marsh die-off and explained differences in herbivorous crab abundance and the severity of die-off across regions. Die-offs in Long Island Sound and Narragansett Bay are following a trajectory similar to die-off on Cape Cod, but are approximately 20 years behind those on Cape Cod. As a result, die-off currently affects 31.2% (SE 2.2) of low-marsh areas in Long Island Sound and Narragansett Bay, less than half the severity of die-off on Cape Cod. Our results contribute to the growing evidence that recreational fishing is an increasing threat to coastal ecosystems and that studying the effects of human activity at regional scales can provide insight into local effects and aid in early detection and potential remediation. Ontogenia Regional de un Incremento en la Mortandad en una Marisma Salada de Nueva Inglaterra. PMID:23566036

Coverdale, Tyler C; Bertness, Mark D; Altieri, Andrew H

2013-04-08

48

How will warming affect the salt marsh foundation species Spartina patens and its ecological role?  

PubMed

Foundation species structure environments and create refuge from environmental stress. In New England high salt marsh, the grass Spartina patens is a foundation species that reduces salinity, anoxia, desiccation, and thermal stresses through canopy shading and root proliferation. In a factorial S. patens-removal and warming field experiment, foundation species removal strongly impacted every aspect of the community, reiterating the important role of the foundation species S. patens in the high marsh. Given this central role, we hypothesized that facilitation by the foundation species would be even more important under warmer conditions by ameliorating more severe thermal stress. However, the ecological role of S. patens was unaffected by experimental warming, and, independent of the presence of the foundation species, warming had only weak effects on the salt marsh ecological community. Only the foundation species itself responded strongly to warming, by significantly increasing aboveground production in warmed plots. Apparently, amelioration of thermal stress is not as important for salt marsh ecosystem function as S. patens' moderation of salinity and desiccation stresses. From these experimental results, we anticipate that climate change-associated thermal stress will not greatly affect S. patens-dominated high marsh communities. In contrast, foundation species loss, an emergent conservation issue in Atlantic salt marshes, represents a critical threat to salt marsh ecosystem function. PMID:20490551

Gedan, Keryn B; Bertness, Mark D

2010-05-20

49

SPATIAL AND THERMAL ECOLOGY OF DIAMONDBACK TERRAPINS (MALACLEMYS TERRAPIN) IN A SOUTH CAROLINA SALT MARSH  

Microsoft Academic Search

East coast barrier islands such as Kiawah Island, South Carolina, have experienced rapid urbanization resulting in alteration of their salt marsh ecosystems since the 1980's. These estuarine ecosystems serve as critical habitat for numerous endemic wildlife such as diamondback terrapins (Malaclemys terrapin) which are particularly vulnerable to anthropogenic disturbances. An intensive six-day radiotelemetric study was initiated to better understand the

LEIGH ANNE HARDEN; NICHOLAS A. DILUZIO; J. WHITFIELD GIBBONS; MICHAEL E. DORCAS

2007-01-01

50

Hydrocarbon degradation potential of salt marsh plant-microorganisms associations.  

PubMed

Estuaries are often considered sinks for contaminants and the cleanup of salt marshes, sensitive ecosystems with a major ecological role, should be carried out by means of least intrusive approaches, such as bioremediation. This study was designed to evaluate the influence of plant-microorganisms associations on petroleum hydrocarbons fate in salt marshes of a temperate estuary (Lima River, NW Portugal). Sediments un-colonized and colonized (rhizosediments) by different plants (Juncus maritimus, Phragmites australis, Triglochin striata and Spartina patens) were sampled in four sites of the lower and middle estuary for hydrocarbon degrading microorganisms (HD), total cell counts (TCC) and total petroleum hydrocarbons (TPHs) assessment. In general, TPHs, HD and TCC were significantly higher (P < 0.05) in rhizosediments than in un-colonized sediments. Also recorded were differences on the abundance of hydrocarbon degraders among the rhizosediment of the different plants collected at the same site (J. maritimus < P. australis < T. striata), with statistically significant differences (P < 0.05) between J. maritimus and T. striata. Moreover, strong positive correlations-0.81 and 0.84 (P < 0.05), between biotic (HD) and abiotic (organic matter content) parameters and TPHs concentrations were also found. Our data clearly suggest that salt marsh plants can influence the microbial community, by fostering the development of hydrocarbon-degrading microbial populations in its rhizosphere, an effect observed for all plants. This effect, combined with the plant capability to retain hydrocarbons around the roots, points out that salt marsh plant-microorganisms associations may actively contribute to hydrocarbon removal and degradation in estuarine environments. PMID:21188477

Ribeiro, Hugo; Mucha, Ana P; Almeida, C Marisa R; Bordalo, Adriano A

2010-12-25

51

Response of a salt marsh microbial community to metal contamination  

NASA Astrophysics Data System (ADS)

Salt marshes are important sinks for contaminants, namely metals that tend to accumulate around plant roots and could eventually be taken up in a process known as phytoremediation. On the other hand, microbial communities display important roles in the salt marsh ecosystems, such as recycling of nutrients and/or degradation of organic contaminants. Thus, plants can benefit from the microbial activity in the phytoremediation process. Nevertheless, above certain levels, metals are known to be toxic to microorganisms, fact that can eventually compromise their ecological functions. In this vein, the aim of present study was to investigate, in the laboratory, the effect of selected metals (Cd, Cu and Pb) on the microbial communities associated to the roots of two salt marsh plants. Sediments colonized by Juncus maritimus and Phragmites australis were collected in the River Lima estuary (NW Portugal), and spiked with each of the metals at three different Effects Range-Median (ERM) concentrations (1, 10×, 50×), being ERM the sediment quality guideline that indicates the concentration above which adverse biological effects may frequently occur. Spiked sediments were incubated with a nutritive saline solution, being left in the dark under constant agitation for 7 days. The results showed that, despite the initial sediments colonized by J. maritimus and P. australis displayed significant (p < 0.05) differences in terms of microbial community structure (evaluated by ARISA), they presented similar microbial abundances (estimated by DAPI). Also, in terms of microbial abundance, both sediments showed a similar response to metal addition, with a decrease in number of cells only observed for the higher addition of Cu. Nevertheless, both Cu and Pb, at intermediate metals levels promote a shift in the microbial community structure, with possibly effect on the ecological function of these microbial communities in salt marshes. These changes may affect plants phytoremediation potential and further work on this subject is in need.

Mucha, Ana P.; Teixeira, Catarina; Reis, Izabela; Magalhães, Catarina; Bordalo, Adriano A.; Almeida, C. Marisa R.

2013-09-01

52

Storm-driven groundwater flow in a salt marsh  

NASA Astrophysics Data System (ADS)

Storms can cause significant groundwater flow in coastal settings, but prior studies of the effects of storms on groundwater flow and transport have largely focused on very large storms and used salinity as a tracer. We have little information about the effects of smaller storms on coastal flow and how storm-induced variability affects key tidal wetlands like salt marshes, which may remain saline throughout a storm. Here we show that even the distant passage of a moderate storm can strongly increase groundwater flow and transport in salt marsh ecosystems and adjacent barrier islands. Groundwater monitoring and radium isotope tracer analyses revealed significant influx of saline creek water into the confined aquifer below the marsh platform, driven by storm surge. This pulse of fluids reached depths exceeding 5 m, and surge-enhanced tides propagated through the aquifer to affect flow in the upland >100 m from the creek bank. Groundwater discharge from the marsh varied significantly prior to the storm, doubling during inundating tides compared to a period of noninundating neap tides. Storm surge then caused groundwater discharge to decline ˜50% compared to similar inundating tides. Ra- and nutrient-poor creek water that entered the confined aquifer below the marsh was quickly enriched in nutrients and carbon, even on 12 h tidal cycles, so that nutrient discharge was likely proportional to groundwater discharge. Storm-related flow could also drive significant contaminant discharge from developed coastlines. The enhanced transport and variability observed here likely affected hundreds of kilometers of the coastline impacted by the storm.

Wilson, Alicia M.; Moore, Willard S.; Joye, Samantha B.; Anderson, Joseph L.; Schutte, Charles A.

2011-02-01

53

Consequences of Climate Change, Eutrophication, and Other Anthropogenic Impacts to Coastal Salt Marshes: Multiple Stressors Reduce Resiliency and Sustainability  

EPA Science Inventory

Coastal salt marshes provide a wide variety of ecosystem services, including habitat for protected vertebrates and ecologically valuable invertebrate fauna, flood protection, and improvements in water quality for adjacent marine and estuarine environments. Here, we consider the ...

54

Influence of multiple stressors on the auto-remediation processes occurring in salt marshes.  

PubMed

Due to increasing global population, salt marshes have been subjected to multiple stressors such as increasing nutrient loadings and historical contamination. In order to better understand how does the salt marsh plants auto-remediation capacity (phytoaccumulation of metals) is affected by cultural eutrophication, an experiment was performed under controlled conditions. Plants were exposure to equal metal concentrations (Zn, Cu, and Ni - micronutrients, and Cd - class B metal) simulating historical contamination and three different concentrations of nitrogen (nitrate) simulating steps of cultural eutrophication. According to our study, under the tested concentrations, cultural eutrophication does not seem to affect Zn, Cu and Ni phytoremediation of H. portulacoides, but the ecosystem service of Cd phytoremediation seems to be promoted. Nevertheless, Cd high toxicity and bioaccumulation should be taken into account, as well as the vulnerability of salt marsh ecosystems, whose reduction will have drastic consequences to the ecosystem health. PMID:21592533

Sousa, Ana I; Lillebø, Ana I; Pardal, Miguel A; Caçador, Isabel

2011-05-17

55

Spatial patterns in accretion on barrier-island salt marshes  

NASA Astrophysics Data System (ADS)

On minerogenic barrier-island salt marshes, sedimentation is spatially heterogeneous. Although the main forcing factors for sedimentation are known, much less is known about the characteristic sizes of this spatial patterning. Such patterning gives information on the spatial component of salt-marsh formation and on the uncertainty in measured accretion rates. We used variograms (geostatistics) to study the size of spatial patterns in the thickness of salt-marsh deposits, based on a database of over 10,000 soil cores. These were taken at various spatial scales ranging from metres to kilometres, along a chronosequence representing 10-150 years of salt-marsh formation at three barrier islands in the Wadden Sea (south-eastern North Sea).The general complexity of salt-marsh accretion was reflected in the observed patterns of the thickness of the marsh deposits. The patterns were nested and ranged in horizontal size from 3 m on sites with micro-topography, to 900 m at the scale of the entire marsh. Their structure and size changed with salt-marsh age and there was no characteristic pattern size. Although the pre-marsh topography is an important large-scale control, during salt-marsh development independent spatial patterns are superimposed.When scaling up data on salt-marsh sedimentation, the presence of spatial patterning adds uncertainty to the prediction. The consequence of the complexity of these patterns is that the spatial uncertainty is a (not necessarily linear) function of the area under consideration, which can only be quantified if it is explicitly measured. Our findings therefore pose a cautionary note to studies of salt-marsh resilience to sea-level rise: reliable estimates can only be derived if they are based on measurements that take into account the entire salt marsh.

de Groot, Alma V.; Veeneklaas, Roos M.; Kuijper, Dries P. J.; Bakker, Jan P.

2011-11-01

56

The influence of Spartina maritima on carbon retention capacity in salt marshes from warm-temperate estuaries.  

PubMed

Salt marshes constitute highly productive systems playing an important role on ecosystem functions. The aim of this study is to compare the role of Spartina maritima salt marshes on carbon cycling. Thus, four salt marshes located in two mesotidal estuarine systems (Tagus and Mondego, two salt marshes per estuary) were studied. The S. maritima above- and belowground biomass, carbon production, decomposition rates (through a litterbag experiment) and carbon content in the sediment were estimated for a one year period in both systems and compared. In Corroios (located at the Tagus estuary) S. maritima salt marsh had the highest belowground production (1008 gC m(-2) y(-1)), slower decomposition rate (k=0.0024 d(-1)), and the highest carbon content in sediments (750 gC m(-2) y(-1)); and thus, the highest carbon retention capacity. The other three salt marshes had comparatively higher aboveground productions, higher decomposition rates and lower carbon retention capacity. Therefore, Corroios had the most important carbon cycling characteristics. As a whole, results show that differences in carbon cycling in salt marshes depend mostly on its own characteristics and maturity, rather than the system itself. The intrinsic characteristics of the salt marshes, namely the physicochemical conditions determined by the maturity of the system, are more important factors affecting the role of warm-temperate mesotidal salt marshes as carbon sinks. PMID:20304438

Sousa, Ana I; Lillebø, Ana I; Pardal, Miguel A; Caçador, Isabel

2010-03-20

57

Remote sensing of wetland conditions in West Coast salt marshes  

NASA Astrophysics Data System (ADS)

The objective of the PEEIR (Pacific Estuarine Ecosystem Indicator Research Consortium) program is to develop new indicators for assessing wetland health or condition. As part of PEEIR program we are investigating the use of imaging spectrometry to map and characterize marsh vegetation of several estuarine systems in California. We obtained airborne Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data, an instrument which measures a detailed reflectance spectrum (400-2500nm) for each pixel, over paired tidal marshes, having either a history of exposure to pollution or no known exposure. AVIRIS image data was analyzed based on comparison to field measurements and reflectance changes measured in hydroponic experiments. We report leaf and canopy reflectance measurements of several common plant species of Pacific coast salt marshes exposed to different concentrations of heavy metals (Cd, V) and crude oil contaminants. Species exhibited differential sensitivities to specific contaminants, however in general, Salicornia virginica, the most salt tolerant species and the dominant species in these wetlands (70-90% cover) was most sensitive to metal and petroleum contaminants. Field measurements of canopy reflectance, biomass and vegetation structure were acquired across GPS-located transects at each field site. The AVIRIS data were calibrated to surface reflectance using the FLAASH radiative transfer code and geometrically registered to coordinates using the 1m USGS digital orthophoto quads. AVIRIS results show spatial patterns of plant stress indicators (e.g., reduced chlorophyll and water contents) are consistent with known patterns of contamination in these tidal wetlands.

Ustin, Susan L.; Lay, Mui C.; Li, Lin

2004-11-01

58

Post-mortem ecosystem engineering by oysters creates habitat for a rare marsh plant.  

PubMed

Oysters are ecosystem engineers in marine ecosystems, but the functions of oyster shell deposits in intertidal salt marshes are not well understood. The annual plant Suaeda linearis is associated with oyster shell deposits in Georgia salt marshes. We hypothesized that oyster shell deposits promoted the distribution of Suaeda linearis by engineering soil conditions unfavorable to dominant salt marsh plants of the region (the shrub Borrichia frutescens, the rush Juncus roemerianus, and the grass Spartina alterniflora). We tested this hypothesis using common garden pot experiments and field transplant experiments. Suaeda linearis thrived in Borrichia frutescens stands in the absence of neighbors, but was suppressed by Borrichia frutescens in the with-neighbor treatment, suggesting that Suaeda linearis was excluded from Borrichia frutescens stands by interspecific competition. Suaeda linearis plants all died in Juncus roemerianus and Spartina alterniflora stands, regardless of neighbor treatments, indicating that Suaeda linearis is excluded from these habitats by physical stress (likely water-logging). In contrast, Borrichia frutescens, Juncus roemerianus, and Spartina alterniflora all performed poorly in Suaeda linearis stands regardless of neighbor treatments, probably due to physical stresses such as low soil water content and low organic matter content. Thus, oyster shell deposits play an important ecosystem engineering role in influencing salt marsh plant communities by providing a unique niche for Suaeda linearis, which otherwise would be rare or absent in salt marshes in the southeastern US. Since the success of Suaeda linearis is linked to the success of oysters, efforts to protect and restore oyster reefs may also benefit salt marsh plant communities. PMID:22644048

Guo, Hongyu; Pennings, Steven C

2012-05-29

59

On salt marsh vegetation in North Korea  

Microsoft Academic Search

The salt marsh vegetation on the west coast of North Korea was studied by the method of the Zürich-Montpellier school. The\\u000a following communities were distinguished:Suaedetum japonicae, Scirpetum iseensis, Artemisietum fukudo, and the following were described as new:Triglochini maritimae-Phragmitetum communis, Artemisio capillaris-Salsoletum komarovii andSalsolo komarovii-Rosetum rugosae. The phytocoenological material was also analysed by means of numerical techniques.\\u000a \\u000a The population density ofSuaeda

Ji?í Kolbek; Ji?í Dostálek; Ivan Jarolímek; Ivan Ostrý; Li Sek-Ha

1989-01-01

60

Methylmercury Cycling and Tidal Exchange in a Chesapeake Bay Salt Marsh (Invited)  

NASA Astrophysics Data System (ADS)

The importance of salt marshes to methylmercury budgets in coastal regions is poorly understood. Given that salt marshes are important coastal features around Chesapeake Bay and in many other coastal areas, and that methylmercury is a bioaccumulated neurotoxin to aquatic biota and the humans that consume them, fully understanding methylmercury sources is an important step in mitigating detrimental health and ecosystem effects. In this research, we highlight the important biogeochemical controls on methylmercury production in a Chesapeake Bay salt marsh and link this production with tidal exchange using hydrological measurements and sampling over a 12-month period. Our findings point to an important linkage between iron cycling and methylmercury production. Net tidal exchange of total mercury and methylmercury showed marked seasonal variation, especially for methylmercury. Overall, we estimate the salt marsh was a large net sink for total mercury (~60 ?g m-2 yr-1) and a net source of methylmercury (~0.25 ?g m-2 yr-1). In addition to significant in situ methylmercury exposure risk to biota that utilize salt marshes as habitat or breeding grounds, the contribution of methylmercury to the estuarine zone as a result of salt marsh tidal exchange is not negligible.

Mitchell, C. P.; Jordan, T. E.; Heyes, A.; Gilmour, C. C.

2010-12-01

61

Effects of historic tidal restrictions on salt marsh sediment chemistry  

Microsoft Academic Search

The effects of tidalrestrictions by diking on salt marshbiogeochemistry were interpreted by comparingthe hydrology, porewater chemistry and solidphase composition of both seasonally floodedand drained diked marshes with adjacentnatural salt marshes on Cape Cod,Massachusetts. Flooding periods weregreatest in natural and least in drainedmarshes.

J. W. PORTNOY; A. E. GIBLIN

1997-01-01

62

ANTHROPOGENIC INFLUENCES ON STREAMS AND THEIR RECEIVING SALT MARSHES  

EPA Science Inventory

Land use and anthropogenic activities in watersheds affect biological, chemical, and physical conditions in streams and receiving coastal salt marshes. Our objective is to compare indicators of stream condition and riparian vegetation with analagous indicators of the coastal salt...

63

Anthropogenic modification of New England salt marsh landscapes  

PubMed Central

Salt marshes play a critical role in the ecology and geology of wave-protected shorelines in the Western Atlantic, but as many as 80% of the marshes that once occurred in New England have already been lost to human development. Here we present data that suggest that the remaining salt marshes in southern New England are being rapidly degraded by shoreline development and eutrophication. On the seaward border of these marshes, nitrogen eutrophication stimulated by local shoreline development is shifting the competitive balance among marsh plants by releasing plants from nutrient competition. This shift is leading to the displacement of natural high marsh plants by low marsh cordgrass. On the terrestrial border of these same marshes, shoreline development is also precipitating the invasion of the common reed, Phragmites, by means of nitrogen eutrophication caused by the removal of the woody vegetation buffer between terrestrial and salt marsh communities. As a consequence of these human impacts, traditional salt marsh plant communities and the plants and animals that are dependent on these habitats are being displaced by monocultures of weedy species.

Bertness, Mark D.; Ewanchuk, Patrick J.; Silliman, Brian Reed

2002-01-01

64

Hydrologic modeling as a predictive basis for ecological restoration of salt marshes  

NASA Astrophysics Data System (ADS)

Roads, bridges, causeways, impoundments, and dikes in the coastal zone often restrict tidal flow to salt marsh ecosystems. A dike with tide control structures, located at the mouth of the Herring River salt marsh estuarine system (Wellfleet, Massachusetts) since 1908, has effectively restricted tidal exchange, causing changes in marsh vegetation composition, degraded water quality, and reduced abundance of fish and macroinvertebrate communities. Restoration of this estuary by reintroduction of tidal exchange is a feasible management alternative. However, restoration efforts must proceed with caution as residential dwellings and a golf course are located immediately adjacent to and in places within the tidal wetland. A numerical model was developed to predict tide height levels for numerous alternative openings through the Herring River dike. Given these model predictions and knowledge of elevations of flood-prone areas, it becomes possible to make responsible decisions regarding restoration. Moreover, tidal flooding elevations relative to the wetland surface must be known to predict optimum conditions for ecological recovery. The tide height model has a universal role, as demonstrated by successful application at a nearby salt marsh restoration site in Provincetown, Massachusetts. Salt marsh restoration is a valuable management tool toward maintaining and enhancing coastal zone habitat diversity. The tide height model presented in this paper will enable both scientists and resource professionals to assign a degree of predictability when designing salt marsh restoration programs.

Roman, Charles T.; Garvine, Richard W.; Portnoy, John W.

1995-07-01

65

Crab induced salt marsh regeneration after the 1991 Gulf War oil spill  

Microsoft Academic Search

The 1991 Gulf War led to the largest oil spill in human history. Over 770 km of coastline from southern Kuwait to Abu Ali Island (Saudi Arabia) were smothered with oil and tar, erasing most of the local plant and animal communities. Salt marshes were most severely hit of the different coastal ecosystem types along the Saudi Arabian coast and

Hans-Jörg Barth

2007-01-01

66

A WATERSHED APPROACH TO UNDERSTANDING ANTHROPOGENIC INFLUENCES ON STREAMS AND THEIR RECEIVING SALT MARSHES  

EPA Science Inventory

Fresh and saltwater ecosystems have customarily been assessed separately. By taking a watershed approach, we are exploring the linkages between stream conditions, the biotic integrity of coastal salt marshes, and land use. Watersheds provide a pathway for point and nonpoint pollu...

67

Tidal salt marshes of the southeast Atlantic Coast: A community profile  

SciTech Connect

This report is part of a series of community profiles on the ecology of wetland and marine communities. This particular profile considers tidal marshes of the southeastern Atlantic coast, from North Carolina south to northern Florida. Alone among the earth's ecosystems, coastal communities are subjected to a bidirectional flooding sometimes occurring twice each day; this flooding affects successional development, species composition, stability, and productivity. In the tidally influenced salt marsh, salinity ranges from less than 1 ppt to that of seawater. Dominant plant species include cordgrasses (Spartina alterniflora and S. cynosuroides), black needlerush (Juncus romerianus), and salt marsh bulrush (Scirpus robustus). Both terrestrail and aquatic animals occur in salt marshes and include herons, egrets ospreys (Pandion haliaetus), bald eagles (Haliaeetus leucocephalus), alligators (Alligator Mississippiensis), manatees (Trichecus manatus), oysters, mussels, and fiddler crabs. Currently, the only significant direct commercial use of the tidal salt marshes is by crabbers seeking the blue crab Callinectes sapidus, but the marshes are quite important recreationally, aesthetically, and educationally. 151 refs., 45 figs., 6 tabs.

Wiegert, R.G.; Freeman, B.J.

1990-09-01

68

Specificity of Salt Marsh Diazotrophs for Vegetation Zones and Plant Hosts: Results from a North American marsh  

PubMed Central

Salt marshes located on the east coast of temperate North America are highly productive, typically nitrogen-limited, and support diverse assemblages of free-living nitrogen fixing (diazotrophic) bacteria. This article reviews and analyzes data from North Inlet estuary (SC, USA), addressing diazotroph assemblage structure and the influence of plant host and environmental conditions on the assemblage. The North Inlet estuary is a salt marsh ecosystem in which anthropogenic influences are minimal and the distributions of diazotrophs are governed by the natural biota and dynamics of the system. Denaturing gradient gel electrophoresis fingerprinting and phylogenetic analyses of recovered sequences demonstrated that the distributions of some diazotrophs reflect plant host specificity and that diazotroph assemblages distributed across marsh gradients are also heavily influenced by edaphic conditions. Broadly distributed diazotrophs that are capable of maintaining populations under all environmental conditions spanning such gradients are also present in these assemblages. Statistical analyses indicate that the structures of diazotroph assemblages in different vegetation zones are significantly (p?salt marsh rhizosphere microenvironments, and corroborate previous findings from different plant hosts growing at several locations within this estuary. The data from these collected works support the hypothesis that the biogeography of microorganisms is non-random and these biogeographic patterns are predictable.

Lovell, Charles R.; Davis, Debra A.

2012-01-01

69

Nitrogen Pools of Macrophyte Species in a Coastal Lagoon Salt Marsh: Implications for Seasonal Storage and Dispersal  

Microsoft Academic Search

High nitrogen (N) loading rates received by coastal bays can have deleterious effects on aquatic ecosystems. Salt marshes\\u000a can intercept land-based N through seasonal plant uptake, denitrification, and burial. Salt marshes fringing Delaware’s Inland\\u000a Bays are characterized by different plant species occurring in close proximity. To evaluate N pool retention and loss for\\u000a the dominant plant species, we measured seasonal

Tracy Elsey-Quirk; Denise M. Seliskar; John L. Gallagher

2011-01-01

70

Hydrodynamic forcing on salt-marsh development: Distinguishing the relative importance of waves and tidal flows  

NASA Astrophysics Data System (ADS)

To unravel the relation between hydrodynamic forcing and the dynamics of the tidal flat-salt-marsh ecosystem, we compared hydrodynamic forcing in terms of proxies relevant to bed sediment motion for four tidal flat-salt-marsh ecosystems that were contrasting in terms of wind exposure (sheltered vs. exposed) and lateral development (shrinking vs. expanding). Wave and current field measurements on these four contrasting tidal flat and salt-marsh ecosystems indicated that the hydrodynamic forcing on the bottom sediment (bed shear stress) was strongly influenced by wind-generated waves, more so than by tidal- or wind-drive currents. The measurements further showed that the hydrodynamic forcing decreased considerably landward of the marsh cliff, highlighting a transition from vigorous (tidal flat and pioneer zone) to sluggish (mature marsh) fluid forcing. Spatial wave modeling using measured wind, revealed that the time-integrated wave forcing on the intertidal mudflat in front of the marsh (i.e., the potential bed sediment pickup) was a factor two higher for salt marshes that are laterally shrinking than for laterally expanding marshes, regardless of whether these marshes were exposed to or sheltered from the wind. The same result could not be obtained from a straightforward wind speed and fetch length approach for estimating wave forcing. This confirmed that wave force estimates required spatial modeling to be consistent with the sites trends of shrinking or expanding marshes and wind exposure is not enough to characterize the wave forcing at these sites. Seasonal changes in wave forcing identified from wind measurements potentially provide an alternative mechanism for marsh cliff formation. During the calm summer, fine sediments switches from the water column to the bed. During the following winter, fine sediment is retained within the vegetated regions while being returned to the water column from the bare tidal flats. The continuous slow upward growth of vegetated areas combined with the seasonal cyclic tidal flat elevations, could, during winter, cause a discontinuity at the bare/vegetated boundary. If this discontinuity grows large enough for plant die-off to occur, then a small cliff will form.

Callaghan, D. P.; Bouma, T. J.; Klaassen, P.; van der Wal, D.; Stive, M. J. F.; Herman, P. M. J.

2010-09-01

71

Proximate nutritive value changes during decomposition of salt marsh plants  

Microsoft Academic Search

Recognition of salt marsh plant detritus as a nutritious source of food for estuarine consumers prompted investigation of in situ decomposition and proximate nutritive values of three plants and their detritus namely: Spartina cynosuroides and Distichlis spicata (Gramineae) and Scirpus americanus (Cyperaceae) growing abundantly in Mississippi tidal marshes. During decomposition to particulate detritus, these plants retain 60–70% organic content and

Armando A. Cruz

1975-01-01

72

Nutrient-Uptake Model in Marsh Ecosystems.  

National Technical Information Service (NTIS)

Mechanistic models of nutrient dynamics in natural wetlands were developed and applied in a study of Kissimmee River (Florida) flood-plain marshes. The models describe hydrodynamics and transport diffusion in wetland basins and the ecological processes of...

L. A. Burns R. B. Taylor

1979-01-01

73

Degradation and resilience in Louisiana salt marshes after the BP-Deepwater Horizon oil spill  

PubMed Central

More than 2 y have passed since the BP–Deepwater Horizon oil spill in the Gulf of Mexico, yet we still have little understanding of its ecological impacts. Examining effects of this oil spill will generate much-needed insight into how shoreline habitats and the valuable ecological services they provide (e.g., shoreline protection) are affected by and recover from large-scale disturbance. Here we report on not only rapid salt-marsh recovery (high resilience) but also permanent marsh area loss after the BP–Deepwater Horizon oil spill. Field observations, experimental manipulations, and wave-propagation modeling reveal that (i) oil coverage was primarily concentrated on the seaward edge of marshes; (ii) there were thresholds of oil coverage that were associated with severity of salt-marsh damage, with heavy oiling leading to plant mortality; (iii) oil-driven plant death on the edges of these marshes more than doubled rates of shoreline erosion, further driving marsh platform loss that is likely to be permanent; and (iv) after 18 mo, marsh grasses have largely recovered into previously oiled, noneroded areas, and the elevated shoreline retreat rates observed at oiled sites have decreased to levels at reference marsh sites. This paper highlights that heavy oil coverage on the shorelines of Louisiana marshes, already experiencing elevated retreat because of intense human activities, induced a geomorphic feedback that amplified this erosion and thereby set limits to the recovery of otherwise resilient vegetation. It thus warns of the enhanced vulnerability of already degraded marshes to heavy oil coverage and provides a clear example of how multiple human-induced stressors can interact to hasten ecosystem decline.

Silliman, Brian R.; van de Koppel, Johan; McCoy, Michael W.; Diller, Jessica; Kasozi, Gabriel N.; Earl, Kamala; Adams, Peter N.; Zimmerman, Andrew R.

2012-01-01

74

Degradation and resilience in Louisiana salt marshes after the BP-Deepwater Horizon oil spill.  

PubMed

More than 2 y have passed since the BP-Deepwater Horizon oil spill in the Gulf of Mexico, yet we still have little understanding of its ecological impacts. Examining effects of this oil spill will generate much-needed insight into how shoreline habitats and the valuable ecological services they provide (e.g., shoreline protection) are affected by and recover from large-scale disturbance. Here we report on not only rapid salt-marsh recovery (high resilience) but also permanent marsh area loss after the BP-Deepwater Horizon oil spill. Field observations, experimental manipulations, and wave-propagation modeling reveal that (i) oil coverage was primarily concentrated on the seaward edge of marshes; (ii) there were thresholds of oil coverage that were associated with severity of salt-marsh damage, with heavy oiling leading to plant mortality; (iii) oil-driven plant death on the edges of these marshes more than doubled rates of shoreline erosion, further driving marsh platform loss that is likely to be permanent; and (iv) after 18 mo, marsh grasses have largely recovered into previously oiled, noneroded areas, and the elevated shoreline retreat rates observed at oiled sites have decreased to levels at reference marsh sites. This paper highlights that heavy oil coverage on the shorelines of Louisiana marshes, already experiencing elevated retreat because of intense human activities, induced a geomorphic feedback that amplified this erosion and thereby set limits to the recovery of otherwise resilient vegetation. It thus warns of the enhanced vulnerability of already degraded marshes to heavy oil coverage and provides a clear example of how multiple human-induced stressors can interact to hasten ecosystem decline. PMID:22733752

Silliman, Brian R; van de Koppel, Johan; McCoy, Michael W; Diller, Jessica; Kasozi, Gabriel N; Earl, Kamala; Adams, Peter N; Zimmerman, Andrew R

2012-06-25

75

PRODUCTION IN COASTAL SALT MARSHES OF SOUTHERN CALIFORNIA  

EPA Science Inventory

Production ecology in southern California coastal salt marshes was investigated by harvesting macrophytes and monitoring environmental factors (substrate salinity, pH, nitrogen, redox, water content, temperature, and tide level) at four locations--Sweetwater River Estuary, Los Pe...

76

The influence of tidal channels on the distribution of salt marsh plant species in Petaluma Marsh, CA, USA  

Microsoft Academic Search

Tidal channels influence the distribution and composition of salt marsh vegetation in a San Francisco Bay salt marsh. Two channel networks in the Petaluma Marsh, Sonoma County, CA, were mapped and characterized using global positioning and geographic information systems. Plant species abundance was sampled on transects placed perpendicular to and extending away from the channel banks. The vegetation showed significant

Eric W. Sanderson; Susan L. Ustin; Theodore C. Foin

2000-01-01

77

Effects of global climate change on coastal salt marshes  

Microsoft Academic Search

A methodology combining ecological modelling with geographical information analysis and remote sensing was employed to determine the effects of sea-level rise in estuarine salt marshes, using the Tagus estuary (Portugal) as a case study. The development of salt marsh vegetation was simulated separately for C3 and C4 plants, using a combined biogeochemical and demographic model. This simulation, which provided small-scale

T. Simas; J. P. Nunes; J. G. Ferreira

2001-01-01

78

Groundwater Nitrate Removal Capacity of Filled Salt Marshes  

NASA Astrophysics Data System (ADS)

Undisturbed salt marshes can serve as sinks for groundwater nitrate flowing through sandy soils underlying salt marsh peat deposits. Many salt marshes have been destroyed by covering the original marsh with fill material to create level, dry surfaces suitable for urban and suburban developments. These alterations may alter groundwater hydrology and nitrate transformations or these buried, organically enriched deposits below the fill could serve as "relic" zones of microbial activity. We measured in situ groundwater denitrification capacity of saturated, sandy soils below buried salt marsh deposits at four filled sites with the 15N-nitrate push-pull method. 15N-enriched nitrate was injected into wells (5 per site) and denitrification rates were obtained by tracking the evolution of 15N-enriched denitrification gases. Three sites were managed lawns and one site had unmanaged scrubby vegetation. The former salt marshes were covered with 60-150 cm of fill material 30-65 years ago. Fill ranged from silt loam to very gravelly sands with 2-75% coarse fragments. At all sites, we observed a buried horizon of enriched carbon material representative of the former salt marsh. One site showed consistently elevated groundwater denitrification capacity at all replicate wells (mean: 60 ?g N kg-1 soil d-1). At the remaining sites, groundwater denitrification capacity was spotty with high intrasite variability. Only one or two of the replicate wells displayed elevated denitrification (>22 ?g N kg-1 soil d-1), but no denitrification was measured in the other wells at those sites. We found no significant correlation between groundwater denitrification and groundwater dissolved oxygen, dissolved organic carbon, temperature, salinity, pH, ambient nitrate concentration, depth below the water table, fill thickness, depth below fill, or fill age. The extreme intrasite variability of groundwater denitrification capacity at these filled salt marsh settings constrasts with our observations at undisturbed salt marshes. We hypothesize that the buried salt marshes are still capable of contributing carbon to fuel groundwater denitrification, but site disturbance appears to alter the spatial pattern of groundwater denitrification capacity. Additionally the longevity of the buried labile carbon pools is a source of uncertainty in evaluating the long-term nitrate sink function of filled salt marshes.

Addy, K.; Gold, A. J.; Stolt, M. H.; Groffman, P. M.

2006-05-01

79

Effect of dominant Spartina species on salt marsh detritus production in SW Atlantic estuaries  

NASA Astrophysics Data System (ADS)

Two cordgrass species of the genus Spartina cohabit in SW Atlantic (southern Brazil 31º48? S to Argentinean Patagonia, 43º20? S) salt marshes. Some salt marshes are dominated by the dense-flowered cordgrass Spartina densiflora (which inhabits the upper intertidal level) and others by the smooth cordgrass Spartina alterniflora (which inhabits the lower intertidal level). We investigated how the different species dominance affects the detritus dynamics in the Bahia Blanca estuary (38º47? S, 62º20? W Argentina). Field measurements of annual detritus production using destructive methods show that both plants are similar. However, detritus of S. alterniflora shows higher decomposition rates than that of S. densiflora . This difference may be due to a larger N content, lower lignocellulose content and lower C/N ratio of S . alternifora when compared with S. densiflora . Moreover, field sampling shows that S. alterniflora has a larger amount of trapped litter that, according to the litterbag method, has higher decomposition rates. Therefore it is highly likely that S. alterniflora salt marshes contribute towards more profitable detritus for estuarine food webs than marshes dominated by S. densiflora . These results illustrate that the composition of the coastal plant community can determine the quality and profitability of the detritus that support estuarine food webs. They also illustrate that salt marshes belonging to a same biogeographic group and even coexisting in great proximity can have very different ecosystemic roles.

Montemayor, Diana I.; Addino, Mariana; Fanjul, Eugenia; Escapa, Mauricio; Alvarez, M. Fernanda; Botto, Florencia; Iribarne, Oscar O.

2011-08-01

80

Comparative Geomorphology of Salt and Tidal Freshwater Marsh Environments  

NASA Astrophysics Data System (ADS)

Temperate estuaries include a spectrum of coastal marshes ranging from highly saline near the ocean to fresh in tributaries with substantial watershed drainage. While the hydrologic, sedimentary, and geomorphic dynamics of salt marshes have been thoroughly investigated, those aspects of tidal freshwater marshes have only begun to be addressed. Based on a recent burst in research on tidal freshwater systems in Chesapeake Bay by different universities, an attempt is made here to provide comparative geomorphology. In terms of similarities, both have tidal channels whose hydraulic geometry is primarily controlled by the tidal prism. Both show decreasing sedimentation and increasing organics with elevation and distance from channels. At seasonal to interannual time scales, the morphodynamics of both show similarities in the interplay among hydroperiod, vegetation, and geomorphology. Rather than simply evolving from youth to maturity, both systems exhibit strong evidence for dynamic equilibrium between process and morphology. Despite these similarities, there are key differences that motivate further research of tidal freshwater marshes. First, whereas salt marshes are limited by sediment supply, tidal fresh ones may not be limited depending on upstream basin size. E.g., fringing marshes along Pumunkey River have very low sediment supply, while deltaic marshes in Bush River and Sassafras River are not supply-limited. Instead, the growth of deltaic fresh marshes is transport limited, as winds and tides can only generate low momentum and turbulence for sediment transport. As illustrated in multiple systems, a constant availability of sediment leads to higher sedimentation in fresh marshes. Second, in high latitude salt marshes where the tidal range is large and the climate cold, ice acts as a strong erosional agent. In fresh marshes, ice serves to sequester sediment and buffer the erosional impact of autumnal vegetation dieback. Third, the high spatial variation in plant associations in fresh marshes allows for a finer control of spatial patterns in sedimentation and erosion than is possible in salt marshes. Finally, the landscape position of fresh marshes places them near riparian forests that can supply large amounts of organics thereby promoting accretion.

Pasternack, G. B.

2002-05-01

81

Inventory and protection of salt marshes from risks of sea-level rise at Acadia National Park, Maine  

USGS Publications Warehouse

Recent U.S. Geological Survey (USGS) climate studies in the northeastern United States have shown substantial evidence of climate-related changes during the last 100 years, including earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies related to climate change are being expanded to include investigation of coastal wetlands that might be at risk from sealevel rise. Coastal wetlands, particularly salt marshes, are important ecosystems that provide wildlife nursery and breeding habitat, migratory bird habitat, water quality enhancement, and shoreline erosion control. The USGS is investigating salt marshes in Acadia National Park with the goal of determining which salt marshes may be threatened by sea-level rise and which salt marshes may be able to adapt to sea-level rise by migrating into adjacent low-lying lands.

Dudley, Robert W.; Nielsen, Martha G.

2011-01-01

82

Chapter 4 Practical Proxies for Tidal Marsh Ecosystem Services  

Microsoft Academic Search

Tidal marshes are valued, protected and restored in recognition of their ecosystem services: (1) high productivity and habitat provision supporting the food web leading to fish and wildlife, (2) buffer against storm wave damage, (3) shoreline stabilization, (4) flood water storage, (5) water quality maintenance, (6) biodiversity preservation, (7) carbon storage and (8) socio?economic benefits. Under US law, federal and

Charles H. Peterson; Kenneth W. Able; Christin Frieswyk DeJong; Michael F. Piehler; Charles A. Simenstad; Joy B. Zedler

2008-01-01

83

Salt marshes: An important coastal sink for dissolved uranium  

SciTech Connect

The global budget for marine uranium demands another geochemical sink other than deep-sea systems, and the coastal environment may host some or all of this missing sink. In a previous paper, we have shown that some large subtidal estuaries are seasonal summer sinks at low salinities. In this paper, we show that intertidal salt marshes are even stronger sinks at all salinities, if for somewhat different reasons. Uranium was sampled in dissolved and particulate fractions over several tidal cycles and seasons for a lower Delaware Bay salt marsh (Canary Creek, Lewes, Delaware, USA), and uniquely, during summer months, the dissolved uranium is nonconservative. Moreover, because uranium extraction is greater on higher tides and occurs over the entire salinity gradient, this processing appears associated with surface of vegetated high marsh, We hypothesize that either (1) uranium scavenging occurs during the process of tidal mixing and attendant flocculation of humic acids and iron oxides-favoring this process is the presence of sulfonate complexes in salt marsh humic substances, and iron coprecipitation during its extensive redox cycling in the salt marsh-or (2) uranium extraction occurs at the marsh surface during extensive flooding of the salt marsh surface sediments-favoring this process is the increase in sulfuric acidity at the summer salt marsh surface that could destabilize the tetracarbonate species of U(VI). The latter option is favored by both field observations of maximum removal at the surface during the spring and summer tide conditions, and selective extraction of sediment phases where uranium is found as adsorbed and complexed forms in the ascorbate-citrate and humic acid fractions, respectively. Mass balance calculations show that under steady-state conditions, nearly two-thirds of the uranium extracted from tidal waters is retained in the sediments, while one-third is exported as U-enriched particles during ebbing tides. 41 refs., 7 figs., 3 tabs.

Church, T.M.; Sarin, M.M.; Fleisher, M.Q.; Ferdelman, T.G. [Univ. of Delaware, Newark, DE (United States)

1996-10-01

84

Microbial community analysis of an Alabama coastal salt marsh impacted by the Deepwater Horizon Oil Spill  

NASA Astrophysics Data System (ADS)

Microbial community responses of an Alabama coastal salt marsh environment to the Deepwater Horizon oil spill were studied by 16S rRNA (PhyloChip) and functional gene (GeoChip) microarray-based analysis. Oil and tar balls associated with the oil spill arrived along the Alabama coast in June 2010. Marsh and inlet sediment samples collected in June, July, and September 2010 from a salt marsh ecosystem at Point Aux Pines Alabama were analyzed to determine if bacterial community structure changed as a result of oil perturbation. Sediment total petroleum hydrocarbon (TPH) concentrations ranged from below detection to 189 mg kg-1 and were randomly dispersed throughout the salt marsh sediments. Total DNA extracted from sediment and particulates were used for PhyloChip and GeoChip hybridization. A total of 4000 to 8000 operational taxonomic units (OTUs) were detected in marsh and inlet samples. Distinctive changes in the number of detectable OTUs were observed between June, July, and September 2010. Surficial inlet sediments demonstrated a significant increase in the total number of OTUs between June and September that correlated with TPH concentrations. The most significant increases in bacterial abundance were observed in the phyla Actinobacteria, Firmicutes, Gemmatimonadetes, Proteobacteria, and Verrucomicrobia. Bacterial richness in marsh sediments also correlated with TPH concentrations with significant changes primarily in Acidobacteria, Actinobacteria, Firmicutes, Fusobacteria, Nitrospirae, and Proteobacteria. GeoChip microarray analysis detected 5000 to 8300 functional genes in marsh and inlet samples. Surficial inlet sediments demonstrated distinctive increases in the number of detectable genes and gene signal intensities in July samples compared to June. Signal intensities increased (> 1.5-fold) in genes associated with petroleum degradation. Genes related to metal resistance, stress, and carbon cycling also demonstrated increases in oiled sediments. This study demonstrates the value of applying phylogenetic and functional gene microarray technology to characterize the extensive microbial diversity of marsh environments. Moreover, this technology provides significant insight into bacterial community responses to anthropogenic oil events.

Beazley, M. J.; Martinez, R.; Rajan, S.; Powell, J.; Piceno, Y.; Tom, L.; Andersen, G. L.; Hazen, T. C.; Van Nostrand, J. D.; Zhou, J.; Mortazavi, B.; Sobecky, P. A.

2011-12-01

85

Ecogeomorphic Properties of Flood-ebb Flows on a Coastal North Carolina Salt-marsh Platform  

NASA Astrophysics Data System (ADS)

Salt marsh ecosystems play a vital role in nutrient processing, shoreline defense, and as habitats for commercially important species. Along the Albemarle and Pamlico Sounds, North Carolina, where the tidal amplitude ranges from 1.0 to 1.5 m, salt marsh communities are expected to undergo a transition from intertidal marshes to subtidal habitats in response to sea-level rise and associated increases in inundation and possibly tidal range. Intertidal areas along the back-barrier sound of Bogue Banks feature well developed networks of tidal channels and exhibit classic macrophyte zonation, with Spartina spp. residing along lower elevations and Juncus roemerianus at higher elevations. As part of a long-term study of macrophyte dynamics, sedimentation and geomorphology in the Albemarle and Pamlico Sounds area, here we describe the pattern of flood-ebb flow on a marsh platform. Continuous measurements from a set of pressure transducers arranged along a marsh transect are used to describe spatial variations in the frequency, duration and depth of inundation as a function of platform elevation, macrophyte biomass, and proximity to the tidal creek. Stem density and diameter of Spartina alterniflora and Juncus roemerianus affect the magnitude of drag forces on the marsh platform during flooding; our field measurements are used to constrain the relationship between macrophyte stand characteristics and these drag forces.

Howell, S.; Furbish, D.; Mudd, S.

2006-12-01

86

The ecology of New England high salt marshes: A community profile  

Microsoft Academic Search

The high salt marshes of New England have evolved in response to sea-level rises through accretion of sediments entrapped by marsh vegetation. Early theories of marsh development are traced and are reconciled in Redfield's synthesis accounting for marsh growth by aggradation over sand and mud flats as well as by accretion on existing marsh surfaces. The shape and appearance of

1982-01-01

87

Salt marsh-atmosphere exchange of energy, water vapor, and carbon dioxide: Effects of tidal flooding and biophysical controls  

NASA Astrophysics Data System (ADS)

The degree to which short-duration, transient floods modify wetland-atmosphere exchange of energy, water vapor, and carbon dioxide (CO2) is poorly documented despite the significance of flooding in many wetlands. This study explored the effects of transient floods on salt marsh-atmosphere linkages. Eddy flux, micrometeorological, and other field data collected during two tidal phases (daytime versus nighttime high tides) quantified the salt marsh radiation budget, surface energy balance, and CO2 flux. Analysis contrasted flooded and nonflooded and day and night effects. The salt marsh surface energy balance was similar to that of a heating-dominated sparse crop during nonflooded periods but similar to that of an evaporative cooling-dominated, well-watered grassy lawn during flooding. Observed increases in latent heat flux and decreases in net ecosystem exchange during flooding were proportional to flood depth and duration, with complete CO2 flux suppression occurring above some flood height less than the canopy height. Flood-induced changes in the salt marsh energy balance were dominated by changes in sensible heat flux, soil heat flux, and surface water heat storage. Parameters suitable for predicting the salt marsh surface energy balance were obtained by calibrating common models (e.g., Penman-Monteith, Priestley-Taylor, and pan coefficient). Biophysical controls on salt marsh-atmosphere exchange were identified following calibration of models describing the coupling of canopy photosynthesis and stomatal conductance in the salt marsh. The effects of flooding on salt marsh-atmosphere exchange are temporary but strongly affect the marsh water, carbon, and energy balance despite their short duration.

Moffett, Kevan B.; Wolf, Adam; Berry, Joe A.; Gorelick, Steven M.

2010-10-01

88

Impacts and interactions of multiple human perturbations in a California salt marsh.  

PubMed

Multiple disturbances to ecosystems can influence community structure by modifying resistance to and recovery from invasion by non-native species. Predicting how invasibility responds to multiple anthropogenic impacts is particularly challenging due to the variety of potential stressors and complex responses. Using manipulative field experiments, we examined the relative impact of perturbations that primarily change abiotic or biotic factors to promote invasion in coastal salt marsh plant communities. Specifically we test the hypotheses that nitrogen enrichment and human trampling facilitate invasion of upland weeds into salt marsh, and that the ability of salt marsh communities to resist and/or recover from invasion is modified by hydrological conditions. Nitrogen enrichment affected invasion of non-native upland plants at only one of six sites, and increased aboveground native marsh biomass at only two sites. Percent cover of native marsh plants declined with trampling at all sites, but recovered earlier at tidally flushed sites than at tidally restricted sites. Synergistic interactions between trampling and restricting tidal flow resulted in significantly higher cover of non-native upland plants in trampled plots at tidally restricted sites. Percent cover of non-native plants recovered to pre-trampling levels in fully tidal sites, but remained higher in tidally restricted sites after 22 months. Thus, perturbations that reduce biotic resistance interact with perturbations that alter abiotic conditions to promote invasion. This suggests that to effectively conserve or restore native biodiversity in altered systems, one must consider impacts of multiple human disturbances, and the interactions between them. PMID:18766384

Goldman Martone, Rebecca; Wasson, Kerstin

2008-09-03

89

Salt stress limitation of seedling recruitment in a salt marsh plant community  

Microsoft Academic Search

Seedling recruitment in salt marsh plant communities is generally precluded in dense vegetation by competition from adults, but is also relatively rare in disturbance-generated bare space. We examined the constraints on seedling recruitment in New England salt marsh bare patches. Under typical bare patch conditions seed germination is severely limited by high substrate salinities. We examined the germination requirements of

Scott W. Shumway; Mark D. Bertness

1992-01-01

90

Salt marsh vegetation change in response to tidal restriction  

Microsoft Academic Search

Vegetation change in response to restriction of the normal tidal prism of six Connecticut salt marshes is documented. Tidal flow at the study sites was restricted with tide gates and associated causeways and dikes for purposes of flood protection, mosquito control, and\\/or salt hay farming. One study site has been under a regime of reduced tidal flow since colonial times,

Charles T. Roman; William A. Niering; R. Scott Warren

1984-01-01

91

Making and Measuring a Model of a Salt Marsh  

ERIC Educational Resources Information Center

|Students are often confused by the difference between the terms "accuracy" and "precision." In the following activities, students explore the definitions of accuracy and precision while learning about salt march ecology and the methods used by scientists to assess salt marsh health. The activities also address the concept that the ocean supports…

Fogleman, Tara; Curran, Mary Carla

2007-01-01

92

Accretion rates and sediment accumulation in Rhode Island salt marshes  

Microsoft Academic Search

In order to test the assumption that accretion rates of intertidal salt marshes are approximately equal to rates of sea-level\\u000a rise along the Rhode Island coast,210Pb analyses were carried out and accretion rates calculated using constant flux and constant activity models applied to sediment\\u000a cores collected from lowSpartina alterniflora marshes at four sites from the head to the mouth of

S. Bricker-Urso; S. W. Nixon; J. K. Cochran; D. J. Hirschberg; C. Hunt

1989-01-01

93

The persistence of endangered Florida Salt Marsh Voles in salt marshes of the central Florida Gulf Coast  

USGS Publications Warehouse

Two endangered Microtus pennsylvanicus dukecampbelli (Florida Salt Marsh Vole) were captured at a new location, in February of 2009, at Lower Suwannee National Wildlife Refuge. Since the species discovery in 1979, only 43 Florida Salt Marsh Voles (hereafter FSM Vole) have been captured. Outside of the type locality, this is only the second documented location for the FSM Vole. Given the difficulty in trapping this species and the lack of information about its life history, its discovery in a new location lends itself to the possibility that it is more widespread in the Central Florida Gulf Coast than previously thought. Although much of the salt marsh in the area is in public ownership, a good deal of it has already been altered by logging or development and is threatened by global climate change. More research is needed to adequately protect and manage the habitat for the FSM Vole. A study of FSM Vole coastal salt marsh habitat could also serve as a valuable monitoring tool for subtle changes in salt marsh habitats as global climate change progresses.

Hotaling, A. S.; Percival, H. F.; Kitchens, W. M.; Kasbohm, J. W.

2010-01-01

94

Salt marshes: An important coastal sink for dissolved uranium  

NASA Astrophysics Data System (ADS)

The global budget for marine uranium demands another geochemical sink other than deep-sea systems, and the coastal environment may host some or all of this missing sink. In a previous paper (Sarin and Church, 1994), we have shown that some large subtidal estuaries are seasonal summer sinks at low salinities. In this paper, we show that intertidal salt marshes are even stronger sinks at all salinities, if for somewhat different reasons. Uranium was sampled in dissolved and particulate fractions over several tidal cycles and seasons for a lower Delaware Bay salt marsh (Canary Creek, Lewes, Delaware, USA), and uniquely, during summer months, the dissolved uranium is nonconservative. Moreover, because uranium extraction is greater on higher tides and occurs over the entire salinity gradient, this processing appears associated with surface of vegetated high marsh. We hypothesize that either (1) uranium scavenging occurs during the process of tidal mixing and attendant flocculation of humic acids and iron oxides—favoring this process is the presence of sulfonate complexes in salt marsh humic substances, and iron coprecipitation during its extensive redox cycling in the salt marsh—or (2) uranium extraction occurs at the marsh surface during extensive flooding of the salt marsh surface sediments—favoring this process is the increase in sulfuric acidity at the summer salt marsh surface that could destabilize the tetracarbonate species of U(VI). The latter option is favored by both field observations of maximum removal at the surface during the spring and summer tide conditions, and selective extraction of sediment phases where uranium is found as adsorbed and complexed forms in the ascorbate-citrate and humic acid fractions, respectively. Mass balance calculations show that under steady-state conditions, nearly two-thirds of the uranium extracted from tidal waters is retained in the sediments, while one-third is exported as U-enriched particles during ebbing tides. Independent confirmation of this balance comes from the measured accumulation rate of uranium buried at depth. This represents the net inventory buried below the geochemically reactive surface responsible for the initial extraction and redistribution of uranium onto sediment or tidally exported phases. Extrapolated globally, uranium burial in salt marshes alone or total marine wetlands including mangroves could comprise at least 10% and perhaps as much as 50% the total marine sink for uranium, or on an area specific basis, up to 50 times their marine areal extent.

Church, T. M.; Sarin, M. M.; Fleisher, M. Q.; Ferdelman, T. G.

1996-10-01

95

Does vegetation prevent wave erosion of salt marsh edges?  

PubMed Central

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves.

Feagin, R. A.; Lozada-Bernard, S. M.; Ravens, T. M.; Moller, I.; Yeager, K. M.; Baird, A. H.

2009-01-01

96

Composition and abundance of resident marsh-surface nekton: comparison between tidal freshwater and salt marshes in Virginia, USA  

Microsoft Academic Search

Previous research on intertidal nekton communities has identifiedimportant determinants of community structure and distribution;\\u000a however, fewstudies have compared nekton utilization of disparate marsh habitats. Inthis study, abundance and distribution\\u000a patterns of resident nekton werecompared between tidal freshwater marsh and salt marsh surfaces varying inflooding depth and\\u000a duration. Nekton were collected in pit traps installedalong elevational transects at four marshes in

David J. Yozzo; David E. Smith

1997-01-01

97

Coatal salt marshes and mangrove swamps in China  

NASA Astrophysics Data System (ADS)

Based on plant specimen data, sediment samples, photos, and sketches from 45 coastal crosssections, and materials from two recent countrywide comprehensive investigations on Chinese coasts and islands, this paper deals with China’s vegetative tidal-flats: salt marshes and mangrove swamps. There are now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about 30% of the mud-coast area of the country and distribute between 18°N (Southern Hainan Island) and 41 °N (Liaodong Bay). Over the past 45 years, about 1750000 acres of salt marshes and 49400 acres of mangrove swamps have been reclaimed. The 2.0×109 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats, the soil basis of coastal helophytes. Different climates result in the diversity of vegetation. The 3˜8 m tidal range favors intertidal zone development. Of over 20 plant species in the salt marshes, native Suaeda salsa, Phragmites australis, Aeluropus littoralis, Zoysia maerostachys, Imperata cylindrica and introduced Spartina anglica are the most extensive in distribution. Of the 41 mangrove swamps species, Kandelia candel, Bruguiera gymnorrhiza, Excoecaria agallocha and Avicennia marina are much wider in latitudinal distribution than the others. Developing stages of marshes originally relevant to the evolution of tidal flats are given out. The roles of pioneer plants in decreasing flood water energy and increasing accretion rate in the Changjiang River delta are discussed.

Yang, Shi-Lun; Chen, Ji-Yu

1995-12-01

98

A monitoring protocol to assess tidal restoration of salt marshes on local and regional scales  

USGS Publications Warehouse

Assessing the response of salt marshes to tidal restoration relies on comparisons of ecosystem attributes between restored and reference marshes. Although this approach provides an objective basis for judging project success, inferences can be constrained if the high variability of natural marshes masks differences in sampled attributes between restored and reference sites. Furthermore, such assessments are usually focused on a small number of restoration projects in a local area, limiting the ability to address questions regarding the effectiveness of restoration within a broad region. We developed a hierarchical approach to evaluate the performance of tidal restorations at local and regional scales throughout the Gulf of Maine. The cornerstone of the approach is a standard protocol for monitoring restored and reference salt marshes throughout the region. The monitoring protocol was developed by consensus among nearly 50 restoration scientists and practitioners. The protocol is based on a suite of core structural measures that can be applied to any tidal restoration project. The protocol also includes additional functional measures for application to specific projects. Consistent use of the standard protocol to monitor local projects will enable pooling information for regional assessments. Ultimately, it will be possible to establish a range of reference conditions characterizing natural tidal wetlands in the region and to compare performance curves between populations of restored and reference marshes for assessing regional restoration effectiveness.

Neckles, H. A.; Dionne, M. D.; Burdick, D. M.; Roman, C. T.; Buchsbaum, R.; Hutchins, E.

2002-01-01

99

Net primary production and decomposition of salt marshes of the Ebre delta (Catalonia, Spain)  

Microsoft Academic Search

Net primary production was measured in three characteristic salt marshes of the Ebre delta: anArthrocnemum macrostachyum salt marsh,A. macrostachyum-Sarcocornia fruticosa mixed salt marsh andS. fruticosa salt marsh. Above-ground and belowground biomass were harvested every 3 mo for 1 yr. Surface litter was also collected from\\u000a each plot. Aboveground biomass was estimated from an indirect non-destructive method, based on the relationship

ANTONI CURCO ´; Carles Ibàñez; John W. Day; Narcís Prat

2002-01-01

100

ASSESSING SALT MARSH HEALTH: A TEST OF THE UTILITY OF FIVE POTENTIAL INDICATORS  

Microsoft Academic Search

We examined the utility of five measures of salt marsh function, focusing on angiosperms and microbes, as potential indicators of salt marsh health. We studied twelve salt marsh creeks around Charleston Harbor, South Carolina, USA, six of which were polluted with metals and\\/or organic compounds and six of which were relatively pristine. Physical variables (sediment clay-silt content, creek water salinity)

Steven C. Pennings; V. Dan Wall; Darrin J. Moore; Mala Pattanayek; Tracy L. Buck; James J. Alberts

2002-01-01

101

EVALUATING THE INTEGRITY OF SALT MARSHES IN NARRAGANSETT BAY SUB-ESTUARIES USING A WATERSHED APPROACH  

EPA Science Inventory

A watershed approach to examine measures of structure and function in salt marshes of similar geomorphology and hydrology in Narragansett Bay is being used to develop a reference system for evaluating salt marsh integrity. We describe integrity as the capability of a salt marsh t...

102

Microclimate and substrate quality controls on nitrogen mineralization in a New England high salt marsh  

Microsoft Academic Search

New England high salt marsh primary productivity is limited by N, but variation in plant N availability across salt marsh vegetation zones has not been quantified. To investigate this, we measured in situ net N mineralization rates throughout the growing season in three zones of a Maine high salt marsh, Juncus gerardii, Spartina patens, and mixed perennial forb. We also

Theresa A. Theodose; Janette Martin

2003-01-01

103

EVALUATING THE INTEGRITY OF SALT MARSHES IN NARRAGANSETT BAY SUBESTUARIES USING A WATESHED APPROACH  

EPA Science Inventory

A watershed approach to examine measures of structure and function in salt marshes of similar geomorphology and hydrology in Narragansett Bay was used to develop a reference system for evaluating salt marsh integrity. We describe integrity as the capability of a salt marsh to pro...

104

Accumulation, distribution and cellular partitioning of mercury in several halophytes of a contaminated salt marsh.  

PubMed

This work evaluates the role of a plant community in mercury (Hg) stabilization and mobility in a contaminated Portuguese salt marsh. With this aim, the distribution of Hg in below and aboveground tissues, as well as the metal partitioning between cellular fractions (soluble and insoluble) in four different species (Triglochin maritima L., Juncus maritimus Lam, Sarcocornia perennis (Miller) A.J. Scott, and Halimione portulacoides (L.) Aellen) was assessed. Mercury accumulation, translocation and compartmentation between organs and cellular fractions were related to the plant species. Results showed that the degree of Hg absorption and retention was influenced both by environmental parameters and metal translocation/partitioning strategies. Different plant species presented different allocation patterns, with marked differences between monocots (T. maritima and J. maritimus) and dicots (S. perennis, H. portulacoides). Overall, the two monocots, in particular T. maritima showed higher Hg retention in the belowground organs whereas the dicots, particularly S. perennis presented a more pronounced translocation to the aboveground tissues. Considering cellular Hg partitioning, all species showed a higher Hg binding to cell walls and membranes rather than in the soluble fractions. This strategy can be related to the high degree of tolerance observed in the studied species. These results indicate that the composition of salt marsh plant communities can be very important in dictating the Hg mobility within the marsh ecosystem and in the rest of the aquatic system as well as providing important insights to future phytoremediation approaches in Hg contaminated salt marshes. PMID:19595432

Castro, Rita; Pereira, Sofia; Lima, Ana; Corticeiro, Sofia; Válega, Mónica; Pereira, Eduarda; Duarte, Armando; Figueira, Etelvina

2009-09-01

105

Spartina Introductions and Consequences in Salt Marshes  

Microsoft Academic Search

Maritime Spartina species define and maintain the shoreline along broad expanses of temperate coasts where they are native. The large Spartina species grow lower on the tidal plane than other vascular plants; tall, stiff stems reduce waves and currents to precipitate sediments from turbid estuarine waters. With the right conditions, roots grow upward through harvested sediments to elevate the marsh.

D. R. Strong; D. A. Ayres

106

Response of salt-marsh carbon accumulation to climate change.  

PubMed

About half of annual marine carbon burial takes place in shallow water ecosystems where geomorphic and ecological stability is driven by interactions between the flow of water, vegetation growth and sediment transport. Although the sensitivity of terrestrial and deep marine carbon pools to climate change has been studied for decades, there is little understanding of how coastal carbon accumulation rates will change and potentially feed back on climate. Here we develop a numerical model of salt marsh evolution, informed by recent measurements of productivity and decomposition, and demonstrate that competition between mineral sediment deposition and organic-matter accumulation determines the net impact of climate change on carbon accumulation in intertidal wetlands. We find that the direct impact of warming on soil carbon accumulation rates is more subtle than the impact of warming-driven sea level rise, although the impact of warming increases with increasing rates of sea level rise. Our simulations suggest that the net impact of climate change will be to increase carbon burial rates in the first half of the twenty-first century, but that carbon-climate feedbacks are likely to diminish over time. PMID:23018965

Kirwan, Matthew L; Mudd, Simon M

2012-09-27

107

Links Between Watershed Activities and the Degradation of Coastal, Tidal Salt Marshes in Southern New England USA  

EPA Science Inventory

Human activities (e.g., land development, wastewater) in coastal watersheds in New England USA are linked with community- and system-level changes in tidal, organic-rich salt marshes. Significant relationships between various indicators of watershed activities and ecosystem stru...

108

Soil Respiration and Belowground Carbon Stores Among Salt Marshes Subjected to Increasing Watershed Nitrogen Loadings in Southern New England  

EPA Science Inventory

Coastal salt marshes are ecosystems located between the uplands and sea, and because of their location are subject to increasing watershed nutrient loadings and rising sea levels. Residential development along the coast is intense, and there is a significant relationship between...

109

Hydrologic variability in a salt marsh: Assessing the links between drought and acute marsh dieback  

NASA Astrophysics Data System (ADS)

It has been hypothesized that acute marsh dieback (AMD) observed along the Gulf Coast and South Atlantic Bight in the early 2000s was the result of drought-induced changes to porewater and sediment chemistry through hypersalinity or through mobilization of metals and acidification associated with redox changes. The impact of drought on coastal wetlands remains unclear because the hydrology of these wetlands is strongly influenced by regular tidal inundation. In order to test the links between hydrologic variability and changes to marsh groundwater conditions that may be stressful to the salt marsh grass Spartina alterniflora, we installed piezometers and passive diffusion samplers in a salt marsh island at North Inlet, South Carolina, where AMD was observed in fall 2001. Significant variations in tidal inundation, rainfall, evapotranspiration, groundwater dynamics, and porewater chemistry were observed. The island was typically inundated twice daily, but there were occasional 19-21 h periods in winter and spring when the marsh was not inundated and a singular event when the marsh was not inundated for three days (March 2008). Enhanced exposure resulted in seasonal redox chemistry changes, as indicated by changes in the ratio of ferrous iron [Fe(II)] to total iron [Fe(II) + Fe(III)], but our observations do not support redox and pH changes as the cause of AMD at this site. Porewater salinity varied from 14 to 40 in the upper 1 m of the marsh. Salinity was most variable near the surface and increased with depth, reflecting root zone transpiration and downward movement of porewater through the marsh mud into the underlying confined sand aquifer. Pearson Correlation tests among porewater constituents and hydrologic parameters indicated significant associations between porewater salinity, tidal inundation, rainfall, and ET, and additional associations between porewater iron concentration, speciation, and tidal inundation. Linear regression model estimates of porewater salinity for 2001-2002 did not indicate the development of hypersalinity during that period. However, these estimates did predict a dramatic increase in salinity that coincided with the beginning of drought conditions just prior to the observation of AMD, suggesting this as a cause for AMD at this site. Drought is predicted to increase over the next century; damage caused by potential increases in the frequency of drought-related AMD may limit the ability of intertidal salt marshes to accommodate sea level rise.

Hughes, Andrea L. H.; Wilson, Alicia M.; Morris, James T.

2012-10-01

110

Responses of salt marsh plant rhizosphere diazotroph assemblages to changes in marsh elevation, edaphic conditions and plant host species.  

PubMed

An important source of new nitrogen in salt marsh ecosystems is microbial diazotrophy (nitrogen fixation). The diazotroph assemblages associated with the rhizospheres (sediment directly affected by the roots) of salt marsh plants are highly diverse, somewhat stable, and consist mainly of novel organisms. In Crab Haul Creek Basin, North Inlet, SC, the distribution of plant types into discrete zones is dictated by relatively minor differences in marsh elevation and it was hypothesized that the biotic and abiotic properties of the plant zones would also dictate the composition of the rhizosphere diazotroph assemblages. Over a period of 1 year, rhizosphere sediments were collected from monotypic stands of the black needlerush, Juncus roemerianus, the common pickleweed, Salicornia virginica, the short and tall growth forms of the smooth cordgrass Spartina alterniflora, and a mixed zone of co-occurring S. virginica and short form, S. alterniflora. DNA was extracted, purified and nifH sequences PCR amplified for denaturing gradient gel electrophoresis (DGGE) analysis to determine the composition of the diazotroph assemblages. The diazotroph assemblages were strongly influenced by season, abiotic environmental parameters and plant host. Sediment chemistry and nitrogen fixation activity were also significantly influenced by seasonal changes. DGGE bands that significantly affected seasonal and zone specific clustering were identified and most of these sequences were from novel diazotrophs, unaffiliated with any previously described organisms. At least one third of the recovered nifH sequences were from a diverse assemblage of Chlorobia, and ?-, ?-, ?- and ?-Proteobacteria. Diazotrophs that occurred throughout the growing season and among all zones (frequently detected) were also mostly novel. These significant sequences indicated that diazotrophs driving the structure of the assemblages were diverse, versatile, and some were ubiquitous while others were seasonally responsive. Several ubiquitous sequences were closely related to sequences of actively N(2) fixing diazotrophs previously recovered from this system. These sequences from ubiquitous and versatile organisms likely indicate the diazotrophs in these rhizosphere assemblages that significantly contribute to ecosystem function. PMID:20963583

Davis, Debra A; Gamble, Megan D; Bagwell, Christopher E; Bergholz, Peter W; Lovell, Charles R

2010-10-21

111

Tidal salt marsh sediment in California, USA. Part 2: Occurrence and anthropogenic input of trace metals  

Microsoft Academic Search

Surface sediment samples (0–5cm) from 5 tidal salt marshes along the coast in California, USA were analyzed to investigate the occurrence and anthropogenic input of trace metals. Among study areas, Stege Marsh located in the central San Francisco Bay was the most contaminated marsh. Concentrations of metals in Stege Marsh sediments were higher than San Francisco Bay ambient levels. Zinc

Hyun-Min Hwang; Peter G. Green; Richard M. Higashi; Thomas M. Young

2006-01-01

112

Effects of plant roots on salt-marsh sediment geochemistry  

Microsoft Academic Search

Sediment cores were collected in two salt marshes of the Tagus estuary in vegetated and non-vegetated areas. EH and pH were measured in loco whereas zinc, lead, sulphate and acid volatile sulphides were determined in the laboratory. The results show the direct influence of vascular plants on the sedimentary chemistry. Sediments containing higher root density are more oxidative and acid,

M. I. Caçador; M. J. Madureira; C. Vale

2000-01-01

113

Results of Total Mercury Analysis in Salt Marsh Invertebrates  

EPA Science Inventory

Analysis of blood samples obtained from saltmarsh sparrows revealed high levels (> 1.0 µg/g(wet)) of mercury (Hg) in sparrows inhabiting a salt marsh site in the Narrow River, RI (also known as Pettaquamscutt River). These analyses were conducted by Oksana Lane at the Biodiversit...

114

Salt marshes: An important coastal sink for dissolved uranium  

Microsoft Academic Search

The global budget for marine uranium demands another geochemical sink other than deep-sea systems, and the coastal environment may host some or all of this missing sink. In a previous paper (Sarin and Church, 1994), we have shown that some large subtidal estuaries are seasonal summer sinks at low salinities. In this paper, we show that intertidal salt marshes are

T. M. Church; M. M. Sarin; M. Q. Fleisher; T. G. Ferdelman

1996-01-01

115

Classification of contamination in salt marsh plants using hyperspectral reflectance  

Microsoft Academic Search

In this paper, we compare the classification effectiveness of two relatively new techniques on data consisting of leaf-level reflectance from five species of salt marsh and two species of crop plants (in four experiments) that have been exposed to varying levels of different heavy metal or petroleum toxicity, with a control treatment for each experiment. If these methodologies work well

Machelle D. Wilson; Susan L. Ustin; David M. Rocke

2004-01-01

116

Characterization of marine debris in North Carolina salt marshes  

Microsoft Academic Search

Marine debris composition, density, abundance, and accumulation were evaluated in salt marshes in Carteret County, North Carolina seasonally between 2007 and 2009. We assessed relationships between human use patterns and debris type. Wave effects on marine debris density were examined using a GIS-based forecasting tool. We assessed the influence of site wave exposure, period, and height on debris quantity. Presence

Shay Viehman; Jenny L. Vander Pluym; Jennifer Schellinger

117

DEGRADATION OF MALATHION BY SALT-MARSH MICROORGANISMS  

EPA Science Inventory

Numerous bacteria from a salt-marsh environment are capable of degrading malathion, an organophosphate insecticide, when supplied with additional nutrients as energy and carbon sources. Seven isolates exhibited ability (48-90%) to degrade malathion as a sole carbon source. Gas an...

118

Population biology of salt marsh and sand dune annuals  

Microsoft Academic Search

Annuals represent a significant component of the vegetation of coastal salt marshes and sand dunes. From many points of view, the two habitats might appear to have little in common. Yet both are characterized by episodes of low water potential, marked spatial and temporal heterogeneity and a zonation which, within certain limits, reflects successional change.

A. R. Watkinson; A. J. Davy

1985-01-01

119

Exposed salt marsh morphodynamics: An example from the Danish Wadden Sea  

NASA Astrophysics Data System (ADS)

In the Danish Wadden Sea, exposed salt marshes grow in the form of sequences of salt marsh platforms which terminate at the tidal flat with an erosional cliff. On the tidal flat adjacent to the salt marsh, a marsh-parallel small depression is usually formed which acts as a tidal channel (landpriel) creating levees on its landward side, on which salt marsh from the mainland spreads seaward with an uneven topography. On the seaward side of the landpriel, patches of slightly higher elevations form as a result of wave action. As plants get a foothold on these patches salt marsh growth is initiated. Along with this process a salt marsh cliff develops against wave attack from the tidal flat during storms. The unit consisting of levee, landpriel and patches of higher elevation eventually silts up and buries the former cliff on top of the levee, so this now stands as a small (? 0.25 m) ridge separating the new platform from the older one. Thus, the salt marsh accretes through a sequence of salt marsh platforms, each with its own landpriel, levee and erosional cliff. The landpriel and levee can be recognised later as topographic lows and highs, respectively, in the sand beneath the fine-grained salt marsh sediments, while the erosional cliff can be recognised in the salt marsh topography. Based on these observations, a conceptual evolutionary/accretionary model for exposed salt marshes with associated erosional cliff, landpriel and levee is presented. The deposition across the salt marsh platform decreases in an exponential manner away from the salt marsh edge at a lower rate than that found on a lee side salt marsh at the Skallingen backbarrier north of the study area. This is interpreted as a result of wave action.

Pedersen, Jørn B. T.; Bartholdy, Jesper

2007-10-01

120

Tidal circulation alteration for salt marsh mosquito control  

NASA Astrophysics Data System (ADS)

Mosquito control ditches designed to increase tidal circulation are widely used as a physical control alternative to insecticidal applications The impact of such ditching on Pacific Coast marshlands was largely unknown before this five-year study of impact in two types of San Francisco Bay salt marshes, a Salicornia virginica (pickleweed) monoculure and a mixed vegetation marsh Results of our studies suggest that ditches cause less environmental disturbance than insecticidal applications The article describes the following environmental consequences of ditching for mosquito control: increased tidal flushing of soils occurs adjacent to ditches compared with that in the open marsh, thereby reducing ground water and soil surface salinities and water table height; primary productivity of S. virginica, as determined by both the harvest method and infrared photographic analysis, is higher directly adjacent to ditches than in the open marsh, distribution of selected arthropod populations is similar at ditches and natural channels, although arthropod community response differs seasonally; aquatic invertebrate biomass is similar within ditched and natural ponds, but diversity is lower in ditched habitats, ditching increases fish diversity and density by improving fish access from tidal channels; ditches provide additional salt marsh song sparrow habitat, although ditches are less preferred than natural channels or sloughs. Management criteria can be used to design ditches that provide effective mosquito control and reduced environmental impact

Resh, Vincent H.; Balling, Steven S.

1983-01-01

121

The environmental consequences of climatic change on British salt marsh vegetation  

Microsoft Academic Search

The present relationship between sea level and the zonation of salt marsh vegetation is discussed in terms of the salt marshes of the Essex and Kent coasts. These marshes are already decreasing in area as a result of a number of different environmental pressures, including the sinking of the land relative to the sea, at a rate of about 3

Laurence A. Boorman

1992-01-01

122

Records of change in salt marshes: a radiochronological study of three Westerschelde (SW Netherlands) marshes.  

PubMed

Three salt marshes on a 50-km transect along the north bank of the Westerschelde Estuary were investigated to determine whether salt marshes in the estuary had responded to shipping channel modifications in recent decades. Marsh accretion rates were estimated mainly from 137Cs profiles with further evidence from 241Am because changes in both rate of deposition and nature of the accreting material precluded use of standard 210Pb(excess) dating models. The 137Cs profiles usually show peaks corresponding to atmospheric deposition from the 1963 fallout maximum and sometimes from the Chernobyl accident, although intervening enhanced 137Cs activities derived from the nuclear reprocessing marine discharges of Sellafield and La Hague are clearly discernible. In all three marshes (Ritthem at the mouth of the estuary and Zuidgors and Waarde at 20 and 45 km upstream), a marked, near-coincident change in the rate of accumulation and in the grain size of material deposited occurred around 1980. This may be related to a combination of channel deepening and straightening operations undertaken in the mid-1970s and/or natural changes in winter wave climate. PMID:11918007

Dyer, F M; Thomson, J; Croudace, I W; Cox, R; Wadsworth, R A

2002-03-01

123

Characterization of marine debris in North Carolina salt marshes.  

PubMed

Marine debris composition, density, abundance, and accumulation were evaluated in salt marshes in Carteret County, North Carolina seasonally between 2007 and 2009. We assessed relationships between human use patterns and debris type. Wave effects on marine debris density were examined using a GIS-based forecasting tool. We assessed the influence of site wave exposure, period, and height on debris quantity. Presence and abundance of debris were related to wave exposure, vegetation type and proximity of the strata to human population and human use patterns. Plastic pieces accounted for the majority of all debris. Small debris (0-5 cm) was primarily composed of foam pieces and was frequently affiliated with natural wrack. Large debris (>100 cm) was encountered in all marsh habitat types surveyed and was primarily composed of anthropogenic wood and derelict fishing gear. Marsh cleanup efforts should be targeted to specific habitat types or debris types to minimize further damage to sensitive habitats. PMID:21986539

Viehman, Shay; Vander Pluym, Jenny L; Schellinger, Jennifer

2011-10-08

124

Algal productivity in salt marshes of Georgia  

Microsoft Academic Search

ABSTRACT Gross primary,production,of algae,in the intertidal,marshes,on the,coast,of Georgia,was measured at various seasons. Measurements were also made of light, temperature, pH, depth of flooding at high tide, and sedimentary chlorophyll. Migration of the algae in t,he sediments,was,observed,along,creek,borders. Production,during,low tide is 150 mg,C\\/m2\\/hr in winter,and 2&30 mg,C\\/mz\\/hr in summer. Production under water, during high tide is 200 mg C\\/m2\\/hr in August and

1959-01-01

125

Plant regeneration from callus cultures of salt marsh hay, Spartina patens, and its cellular-based salt tolerance  

Microsoft Academic Search

Salt marsh hay, Spartina patens (Ait.) Muhl. (Poaceae), is a perennial salt-tolerant grass common in salt marshes and sand dunes of the Atlantic and Gulf coasts of the USA, and grows vigorously at coastal seawater salinity. To study the salt tolerance mechanisms that operate in S. patens at the cellular level, a tissue culture and regeneration protocol for this species

Xianggan Li; Denise M. Seliskar; Jennifer A. Moga; John L. Gallagher

1995-01-01

126

Seasonal Patterns of CO2 and Water Vapor Exchange of Three Salt Marsh Succulents.  

National Technical Information Service (NTIS)

Diurnal carbon dioxide exchange patterns of three salt marsh succulents, Borrichia frutescens, Batis maritima and Salicornia virginica, were determined on a seasonal basis in the marsh at Sapelo Island, Georgia. Year-round photosynthetic activity was obse...

A. E. Antlfinger E. L. Dunn

1979-01-01

127

Salt marsh vegetation response to edaphic and topographic changes from upland sedimentation in a Pacific estuary  

Microsoft Academic Search

This study investigated how changes in salt marsh soil properties and topography on sediment fans related to shifts in salt\\u000a marsh plant community composition in the Elkhorn Slough Watershed, California, USA. Several sediment fans have formed in this\\u000a watershed as soil eroding from farms moved downslope, filling marshes, mudflats, and channels. Sandy sediment deposition increased\\u000a marsh plain elevation and altered

Kristin B. Byrd; Maggi Kelly

2006-01-01

128

Disturbance and Recovery of Salt Marsh Arthropod Communities following BP Deepwater Horizon Oil Spill  

PubMed Central

Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration activities that historically have impacted intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the terrestrial arthropod community and marine invertebrates found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes. Sampling occurred in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails were unaffected. One year later, crab and arthropods had largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure and quite resilient, able to recover from exposure within a year if host plants remain healthy.

McCall, Brittany D.; Pennings, Steven C.

2012-01-01

129

Does seed availability limit plant establishment during salt marsh restoration?  

Microsoft Academic Search

Patterns of seed dispersal and seed bank accumulation need to be known to predict the species that will recruit into restoration\\u000a sites versus those that must be introduced. We assessed the temporal and spatial patterns of seed availability and seed accumulation\\u000a on the salt marsh plain of an 8-ha resforation site, based on seedlings that emerged from tidal material, wrack,

Hem Nalini Morzaria-Luna; Joy B. Zedler

2007-01-01

130

Photosynthesis and respiration of exposed salt-marsh fucoids  

Microsoft Academic Search

Photosynthesis and respiration of the salt-marsh fucoids Ascophyllum nodosum ecad scorpioides and Fucus vesiculosus were investigated using an infrared CO2 gas analyzer under a variety of light intensities, temperatures, and levels of desiccation while the algae were exposed to the atmosphere. Results indicated that net photosynthesis (0.5 to 2.0 mg C\\/g dry weight\\/h) saturated rapidly at light intensities (0.1 to

B. H. Brinkhuis; N. R. Tempel; R. F. Jones

1976-01-01

131

White Phosphorus Poisoning of Waterfowl in an Alaskan Salt Marsh  

Microsoft Academic Search

The cause of the yearly death of an estimated 1,000 to 2,000 migrating dabbling ducks (Anas spp.) and 10 to 50 swans (Cygnus buccinator and C. columbianus) has remained a mystery for the last ten years in Eagle River Flats (ERF), a 1,000 ha estuarine salt marsh near Anchorage, Alaska, used for artillery training by the U.S. Army. We have

Charles H. Racine; Marianne E. Walsh; Bill D. Roebuck; Charles M. Collins; Darryl Calkins

132

Role of crab herbivory in die-off of New England salt marshes.  

PubMed

Die-offs of cordgrass are pervasive throughout western Atlantic salt marshes, yet understanding of the mechanisms precipitating these events is limited. We tested whether herbivory by the native crab, Sesarma reticulatum, is generating die-offs of cordgrass that are currently occurring on Cape Cod, Massachusetts (U.S.A.), by manipulating crab access to cordgrass transplanted into die-off areas and healthy vegetation. We surveyed 12 Cape Cod marshes to investigate whether the extent of cordgrass die-off on creek banks, where die-offs are concentrated, was related to local Sesarma grazing intensity and crab density. We then used archived aerial images to examine whether creek bank die-off areas have expanded over the past 2 decades and tested the hypothesis that release from predation, leading to elevated Sesarma densities, is triggering cordgrass die-offs by tethering crabs where die-offs are pervasive and where die-offs have not yet been reported. Intensity of crab grazing on transplanted cordgrass was an order of magnitude higher in die-off areas than in adjacent vegetation. Surveys revealed that Sesarma herbivory has denuded nearly half the creek banks in Cape Cod marshes, and differences in crab-grazing intensity among marshes explained >80% of variation in the extent of the die-offs. Moreover, the rate of die-off expansion and area of marsh affected have more than doubled since 2000. Crab-tethering experiments suggest that release from predation has triggered elevated crab densities that are driving these die-offs, indicating that disruption of predator-prey interactions may be generating the collapse of marsh ecosystems previously thought to be exclusively under bottom-up control. PMID:19183205

Holdredge, Christine; Bertness, Mark D; Altieri, Andrew H

2008-12-16

133

Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.  

PubMed

Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4)NO(3))-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication. PMID:22879873

Nelson, Joanna L; Zavaleta, Erika S

2012-08-07

134

Salt marsh hydrology data web site facilitates research  

NASA Astrophysics Data System (ADS)

The interface between maritime forests and inter-tidal salt marshes along the southeastern coast of the United States is a major ecological boundary characterized by a sequence of botanical zones that typically consist of pine/ oak forest>Iva>Juncus>Salicornia>Spartina. In addition to questions regarding the physical and chemical factors that govern this ecotone, this interface is of interest because of the potential for groundwater flow to transfer nutrients and pollutants from developed uplands to the adjacent marshes. The interface is also of interest because it is presumably migrating upslope as a result of ongoing sea level rise and concomitant aquifer salinization.A new Web site, http://links.baruch.sc.edu/data/GRNDWATER/data/data.htm, contains long-term and spatially dense measurements of groundwater heads and salinity from a network of nested piezometers that has been installed along three forest-marsh transects across the Crab Haul Creek finger marsh basin at the North Inlet-Winyah Bay National Estuarine Research Reserve in Georgetown County South Carolina (Figure 1).

Gardner, L. R.; Reeves, H. W.

135

Assessing salt marsh health: A test of the utility of five potential indicators  

Microsoft Academic Search

We examined the utility of five measures of salt marsh function, focusing on angiosperms and microbes, as potential indicators\\u000a of salt marsh health. We studied twelve salt marsh creeks around Charleston Harbor, South Carolina, USA, six of which were\\u000a polluted with metals and\\/or organic compounds and six of which were relatively pristine. Physical variables (sediment clay-silt\\u000a content, creek water salinity)

Steven C. Pennings; V. Dan Wall; Darrin J. Moore; Mala Pattanayek; Tracy L. Buck; James J. Alberts

2002-01-01

136

Monitoring Food Web Changes in Tide-Restored Salt Marshes: A Carbon Stable Isotope Approach  

Microsoft Academic Search

Primary producer (angiosperms, macroalgae, submerged aquatic vegetation), suspended particulate matter, and Fundulus heteroclitus isotope values (d 13 C, d 15 N, d 34 S) were examined to assess their use as indicators for changes in food web support functions in tidally-restored salt marshes. Study sites, located throughout the southern New England region (USA), ranged from Spartina alterniflora-dominated reference marshes, marshes

ANDREW S. WOZNIAK; CHARLES T. ROMAN; S AM C. WAINRIGHT; R ICHARD A. MCKINNEY

2006-01-01

137

Temporal and spatial variation of arbuscular mycorrhizas in salt marsh plants of the Tagus estuary (Portugal)  

Microsoft Academic Search

The factors which may influence temporal and spatial variation in plant arbuscular mycorrhizal (AM) colonization and propagule occurrence were evaluated in a Portuguese salt marsh poor in plant diversity. Two distinct sites were studied: a more-flooded (low marsh) and a less-flooded zone (high marsh). AM root colonization, AM fungal spore number and inoculum potential, soil edaphic parameters and tidal flooding

Luís M. Carvalho; Isabel Caçador; M. Martins-Loução

2001-01-01

138

Belowground herbivory increases vulnerability of New England salt marshes to die-off.  

PubMed

Belowground herbivory is commonly overlooked as a mechanism of top-down control in vegetated habitats, particularly in aquatic ecosystems. Recent research has revealed that increased densities of the herbivorous crab Sesarma reticulatum have led to runaway herbivory and widespread salt marsh die-off on Cape Cod, Massachusetts, USA. Aboveground herbivory is a major driver of this cordgrass habitat loss, but the role of belowground grazing is poorly understood. Sesarma live in communal burrows typically consisting of 1-2 openings and containing 2-3 crabs. However, at die-off sites, burrow complexes can cover > 90% of the low marsh zone, with crab densities as high as 50 crabs/m2 and burrow opening densities of 170 openings/m2. The magnitude of belowground Sesarma activity in association with salt marsh die-off provides an excellent opportunity to extend our knowledge of belowground herbivory impacts in coastal wetlands. Since Sesarma burrows allow access to cordgrass roots and rhizomes, and Sesarma are frequently restricted to burrows by thermal stress and predation, we hypothesized that belowground herbivory would be widespread in die-off areas. We experimentally demonstrate that Sesarma readily eat belowground roots and rhizomes in addition to aboveground cordgrass leaves. We then partitioned above- and belowground herbivory with field manipulations and found that belowground grazing is not only common, but can cause total plant mortality. Additional experiments revealed that plants remain vulnerable to belowground herbivory even after reaching a size refuge from aboveground grazing. This suggests that belowground herbivory contributes to salt marsh die-offs and adds to growing evidence that belowground herbivory is a widespread structuring force in plant communities that can limit habitat persistence. PMID:23094380

Coverdale, Tyler C; Altieri, Andrew H; Bertness, Mark D

2012-09-01

139

Ecosystem Resilience of Coastal Marshes Following a Massive Oiling Event  

NASA Astrophysics Data System (ADS)

The Deepwater Horizon spill released an estimated 6.7 x 105 m3 of crude oil into the marine environment, leading to widespread fears of an environmental catastrophe. A considerable fraction found its way into Barataria Bay, one of the largest and most productive of the coastal bays in the Mississippi River delta. Beginning in May 2010, crude oil was transported to the northerly edge of the bay under the influence of southerly winds, where it was trapped by the fringing 5 - 20 m of Spartina alterniflora marsh. This heavy oiling led to the widespread mortality of marsh plants along this band of heavy oiling. However, on July 17, 2010 new shoots, often ~10 cm high, were observed in the die-off areas. Subsequently, re-growth was further quantified with digital photogrammetry. This re-growth suggests that the widespread oiling led to stem mortality, not root mortality. These findings have important implications for our understanding of ecosystem resilience, and for the impact of this massive oil spill on the erosion of coastal wetlands.

Kolker, A. S.; Ameen, A. D.; Bianchi, T. S.; Cook, R. L.; Green, N.; Kolic, P.; Zhang, Y.

2010-12-01

140

Loss of 'blue carbon' from coastal salt marshes following habitat disturbance.  

PubMed

Increased recognition of the global importance of salt marshes as 'blue carbon' (C) sinks has led to concern that salt marshes could release large amounts of stored C into the atmosphere (as CO2) if they continue undergoing disturbance, thereby accelerating climate change. Empirical evidence of C release following salt marsh habitat loss due to disturbance is rare, yet such information is essential for inclusion of salt marshes in greenhouse gas emission reduction and offset schemes. Here we investigated the stability of salt marsh (Spartinaalterniflora) sediment C levels following seagrass (Thallasiatestudinum) wrack accumulation; a form of disturbance common throughout the world that removes large areas of plant biomass in salt marshes. At our study site (St Joseph Bay, Florida, USA), we recorded 296 patches (7.5 ± 2.3 m(2) mean area ± SE) of vegetation loss (aged 3-12 months) in a salt marsh meadow the size of a soccer field (7 275 m(2)). Within these disturbed patches, levels of organic C in the subsurface zone (1-5 cm depth) were ~30% lower than the surrounding undisturbed meadow. Subsequent analyses showed that the decline in subsurface C levels in disturbed patches was due to loss of below-ground plant (salt marsh) biomass, which otherwise forms the main component of the long-term 'refractory' C stock. We conclude that disturbance to salt marsh habitat due to wrack accumulation can cause significant release of below-ground C; which could shift salt marshes from C sinks to C sources, depending on the intensity and scale of disturbance. This mechanism of C release is likely to increase in the future due to sea level rise; which could increase wrack production due to increasing storminess, and will facilitate delivery of wrack into salt marsh zones due to higher and more frequent inundation. PMID:23861964

Macreadie, Peter I; Hughes, A Randall; Kimbro, David L

2013-07-08

141

Low Persistence of Bacillus thuringiensis Serovar israelensis Spores in Four Mosquito Biotopes of a Salt Marsh in Southern France  

Microsoft Academic Search

We studied the persistence of Bacillus thuringiensis serovar israelensis (Bti) in a typical breeding site of the mosquito Ochlerotatus caspius in a particularly sensitive salt marsh ecosystem following two Bti-based larvicidal applications (Vectobac®12AS, 1.95 L\\/ha).\\u000a The treated area was composed of four larval biotopes that differed in terms of the most representative plant species (Sarcocornia fruticosa, Bolboschoenus maritimus, Phragmites australis, and

Myriam Hajaij; Alexandre Carron; Julien Deleuze; Bruno Gaven; Marie-Laure Setier-Rio; Gerard Vigo; Isabelle Thiéry; Christina Nielsen-LeRoux; Christophe Lagneau

2005-01-01

142

Milieucontaminatie door Metalen en Fluor op het Verdronken Land van Saeftinge en de Effecten Ervan op Schapen (Environmental Pollution with Metals and Fluorine in the Saeftinge Salt Marsh and Its Effect on Sheep).  

National Technical Information Service (NTIS)

The Saeftings salt marsh in the Westerschelde estuary (south-western part of The Netherlands) represents one of the very few tidal brackish marsh ecosystems in Western Europe. During the period May 1983 to May 1985 its local pollution with metals and fluo...

A. J. Baars W. G. Beeftink J. J. Pekelder

1985-01-01

143

Net ecosystem CO 2 exchange in a temperate cattail marsh in relation to biophysical properties  

Microsoft Academic Search

Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured at a temperate cattail marsh using the eddy covariance technique in order to examine the relationships between NEE, weather, and vegetation properties. Analyses of CO2 fluxes for a complete year (May 9, 2005 to May 30, 2006) showed that the marsh wetland was a net CO2 sink for each month

Marie-Claude Bonneville; Ian B. Strachan; Elyn R. Humphreys; Nigel T. Roulet

2008-01-01

144

Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine  

USGS Publications Warehouse

Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median size of 1.0 ha. Inundation contours were mapped at 110 salt marshes. Approximately 350 ha of low-lying upland areas adjacent to these marshes will be inundated with 60 cm of sea-level rise. Many of these areas are currently freshwater wetlands. There are potential barriers to marsh migration at 27 of the 114 marshes. Although only 23 percent of the salt marshes in the study are on ANP property, about half of the upland areas that will be inundated are within ANP; most of the predicted inundated uplands (approximately 170 ha) include freshwater wetlands in the Northeast Creek and Bass Harbor Marsh areas. Most of the salt marshes analyzed do not have a significant amount of upland area available for migration. Seventy-five percent of the salt marshes have 20 meters or less of adjacent upland that would be inundated along most of their edges. All inundation contours, salt marsh locations, potential barriers, and survey data are stored in geospatial files for use in a geographic information system and are a part of this report.

Nielsen, Martha G.; Dudley, Robert W.

2013-01-01

145

Influence of Spartina alterniflora on the mobility of heavy metals in salt marsh sediments of the Yangtze River Estuary, China.  

PubMed

Using bio-disturbed sulphide to trace the mobility and transformation of Cu, Pb, Ni and Zn in the sediments of the Spartina alterniflora-dominated salt marsh in the Yangtze River Estuary, measurements were made of the seasonal variations of acid-volatile sulphide (AVS) and of the simultaneously extracted metals (SEM) in the rhizosphere sediments. Microcosm incubation experiments recreating flooding conditions were conducted to evaluate the effect of AVS and other metal binding phases upon the dynamics of Cu, Pb, Ni and Zn in the salt marsh sediments. The results demonstrate that the ratio values of SEM/AVS have a significant seasonal variation in the rhizosphere sediments and that the anoxic conditions in the sediments were likely enhanced by S. alterniflora during the summer and autumn compared with the anoxic conditions resulting from the native species Phragmites australis and Scirpus mariqueter. The incubation experiments suggest that Fe(III) and Mn(IV/III) (hydr)oxides provide important binding sites for heavy metals under oxic conditions, and sulphide provides important binding sites for the Cu and Pb under anoxic conditions. Our observations indicate that the mobility of heavy metals in the salt marsh sediments is strongly influenced by biogeochemical redox processes and that the invasive S. alterniflora may increase the seasonal fluctuation in heavy metal bioavailability in the salt marsh ecosystem. PMID:22821343

Wang, Yongjie; Zhou, Limin; Zheng, Xiangmin; Qian, Peng; Wu, Yonghong

2012-07-22

146

National survey of planted salt marshes (Vegetative stabilization and wave stress)  

Microsoft Academic Search

There have been many recent attempts to establish salt marshes in the coastal United States. Plantings are generally made\\u000a for the purpose of shore protection, dredged material stabilization, or habitat development. During 1980 a survey was made\\u000a of recent and historic salt marsh planting projects. Data were collected in 104 planted marshes in 12 coastal states. The\\u000a relative stability of

Paul L. Knutson; Julie C. Ford; Margaret R. Inskeep; John Oyler

1981-01-01

147

Assessing the wildlife habitat value of New England salt marshes: I. Model and application  

Microsoft Academic Search

We developed an assessment model to quantify the wildlife habitat value of New England salt marshes based on marsh characteristics\\u000a and the presence of habitat types that influence habitat use by terrestrial wildlife. Applying the model to 12 salt marshes\\u000a located in Narragansett Bay, RI resulted in assessment scores that ranged over a factor of 1.5 from lowest to highest.

Richard A. McKinney; Michael A. Charpentier; Cathleen Wigand

2009-01-01

148

Does low temperature prevent Spartina alterniflora from expanding toward the austral-most salt marshes?  

Microsoft Academic Search

Along the Atlantic coast of South America, the northern salt marshes (lower than 43°S) are dominated by Spartina species while the southern salt marshes (greater than 43°S) are dominated by Sarcocornia perennis. The most abundant Spartina species are Spartina densiflora which is present in most coastal marshes, and Spartina alterniflora that was never recorded above the ~42°25?S. It is not clear

Yanina L. Idaszkin; Alejandro Bortolus

2011-01-01

149

Stratigraphic and Ecophysical Characterizations of Salt Pools: Dynamic Landforms of the Webhannet Salt Marsh, Wells, ME, USA  

Microsoft Academic Search

Salt pools are water-filled depressions common to north-temperate salt marshes. In Wells, ME, USA, cores reveal a unique salt\\u000a pool signature consisting of water-saturated dark-gray mud often containing fragments of Ruppia maritima. Cores through pool sediment reenter salt marsh peat, not tidal flat sediment, demonstrating that most pools are of secondary\\u000a origin. A principal component analysis of attribute data collected

Kristin R. Wilson; Joseph T. Kelley; Arie Croitoru; Michele Dionne; Daniel F. Belknap; Robert Steneck

2009-01-01

150

Microbial Community Composition and Denitrifying Enzyme Activities in Salt Marsh Sediments  

Microsoft Academic Search

Denitrifying microbial communities and denitrification in salt marsh sediments may be affected by many factors, including environmental conditions, nutrient availability, and levels of pollutants. The objective of this study was to examine how microbial community composition and denitrification enzyme activities (DEA) at a California salt marsh with high nutrient loading vary with such factors. Sediments were sampled from three elevations,

Yiping Cao; Peter G. Green; Patricia A. Holden

2008-01-01

151

IMPACTS OF NITROGEN LOADING ON SALT MARSH INTEGRITY IN NEW ENGLAND, USA  

EPA Science Inventory

Salt marsh habitat integrity is linked with the ability to provide good water quality and high biodiversity. We measured high denitrification enzyme activity (DEA) in ten coastal salt marshes in Narragansett Bay, Rhode Island (seasonal means ranging from 7,476 - 53,494 kg N-1ha-...

152

Assessing Wildlife Habitat Value of New England Salt Marshes: II. Model Testing and Validation  

EPA Science Inventory

We test a previously described model to assess the wildlife habitat value of New England salt marshes by comparing modeled habitat values and scores with bird abundance and species richness at sixteen salt marshes in Narragansett Bay, Rhode Island USA. Assessment scores ranged f...

153

Copper and lead concentrations in salt marsh plants on the Suir Estuary, Ireland  

Microsoft Academic Search

Concentrations of Cu and Pb were determined in the roots and shoots of six salt marsh plant species, and in sediment taken from between the roots of the plants, sampled from the lower salt marsh zone at four sites along the Suir Estuary in autumn 1997. Cu was mainly accumulated in the roots of monocotyledonous and dicotyledonous species. Pb was

E. J Fitzgerald; J. M Caffrey; S. T Nesaratnam; P McLoughlin

2003-01-01

154

Facilitation May Buffer Competitive Effects: Indirect and Diffuse Interactions among Salt Marsh Plants  

Microsoft Academic Search

Direct interactions among plant species may be highly modified by indirect or diffuse effects within a multispecies com- munity. We investigated the direct and diffuse effects of two salt marsh perennials, Monanthechloe littoralis and Arthrocnemum sub- terminale, on winter annuals and the perennial herb Limonium cal- ifornicum in a salt marsh in central California. In permanent plots, Monanthechloe had expanded

2000-01-01

155

Interaction between hydrodynamics and salt marsh dynamics: An example from Jiangsu coast  

Microsoft Academic Search

Salt marshes are distributed along more than 400 km of the Jiangsu coast in Eastern China, which are regarded as important habitats and serve as coastal protection as well. Previous research has proven that salt-marsh vegetation can reduce current velocity and dampen waves by its stems and leaves. Reversely, hydrodynamic forces also have a significant influence on the growth of

Z. Hu; M. J. F. Stive; T. J. Zitman; Q. H. Ye; Z. B. Wang; A. Luijendijk; Z. Gong; T. Suzuki

2011-01-01

156

TOP-DOWN CONTROL OF SPARTINA ALTERNIFLORA PRODUCTION BY PERIWINKLE GRAZING IN A VIRGINIA SALT MARSH  

Microsoft Academic Search

Top-down forces, such as grazing and predation, have long been thought to be unimportant in controlling plant growth in salt marshes. Instead, bottom-up forces, such as porewater ammonium and oxygen availability, are thought to be the primary regulating factors. In the field, we observed the periwinkle, Littoraria irrorata, grazing on live salt- marsh cordgrass, Spartina alterniflora. To examine the relative

Brian R. Silliman; Jay C. Zieman

2001-01-01

157

COASTAL SALT MARSH COMMUNITY CHANGE IN NARRAGANSETT BAY IN RESPONSE TO CULTURAL EUTROPHICATION  

EPA Science Inventory

Coastal salt marshes are susceptible to cultural eutrophication, particularly the over-enrichment of nitrogen, because they are often located where surface water and groundwater discharge into estuaries. In this report, the current areal extent of coastal salt marshes in Narrag...

158

Comparison of wetland structural characteristics between created and natural salt marshes in southwest Louisiana, USA  

USGS Publications Warehouse

The use of dredge material is a well-known technique for creating or restoring salt marshes that is expected to become more common along the Gulf of Mexico coast in the future. However, the effectiveness of this restoration method is still questioned. Wetland structural characteristics were compared between four created and three natural salt marshes in southwest Louisiana, USA. The created marshes, formed by the pumping of dredge material into formerly open water areas, represent a chronosequence, ranging in age from 3 to 19 years. Vegetation and soil structural factors were compared to determine whether the created marshes become more similar over time to the natural salt marshes. Vegetation surveys were conducted in 1997, 2000, and 2002 using the line-intercept technique. Site elevations were measured in 2000. Organic matter (OM) was measured in 1996 and 2002, while bulk density and soil particle-size distribution were determined in 2002 only. The natural marshes were dominated by Spartina alterniflora, as were the oldest created marshes; these marshes had the lowest mean site elevations ( 35 cm NGVD) and became dominated by high marsh (S. patens, Distichlis spicata) and shrub (Baccharis halimifolia, Iva frutescens) species. The higher elevation marsh seems to be following a different plant successional trajectory than the other marshes, indicating a relationship between marsh elevation and species composition. The soils in both the created and natural marshes contain high levels of clays (30-65 %), with sand comprising < 1 % of the soil distribution. OM was significantly greater and bulk density significantly lower in two of the natural marshes when compared to the created marshes. The oldest created marsh had significantly greater OM than the younger created marshes, but it may still take several decades before equivalency is reached with the natural marshes. Vegetation structural characteristics in the created marshes take only a few years to become similar to those in the natural marshes, just so long as the marshes are formed at a proper elevation. This agrees with other studies from North Carolina and Texas. However, it will take several decades for the soil characteristics to reach equivalency with the natural marshes, if they ever will.

Edwards, K. R.; Proffitt, C. E.

2003-01-01

159

INTERSPECIFIC INTERACTIONS AMONG HIGH MARSH PERENNIALS IN A NEW ENGLAND SALT MARSH1  

Microsoft Academic Search

High marsh habitats in New England exhibit conspicuous zonation of vas- cular plants. Spartina patens and Juncus gerardi dominate the seaward and terrestrial borders of the high marsh, respectively, whereas Dist~chlis spicata is common in disturbed habitats. In this paper I examine the role of interspecific interactions among these marsh perennials in maintaining marsh plant zonation. Removal and transplant experiments

MARK D. BERTNESS

1991-01-01

160

Substrate mediates consumer control of salt marsh cordgrass on Cape Cod, New England.  

PubMed

Cordgrass die-offs in Cape Cod, Massachusetts, USA, salt marshes have challenged the view that the primary production of New England salt marshes is controlled by physical factors. These die-offs have increased dramatically over the last decade and are caused by the common herbivorous marsh crab Sesarma reticulatum, but other factors that control crab impacts remain unclear. We examined the influence of plant nutrient supply and disturbances on Sesarma herbivory by fertilizing plots and creating experimental disturbances, since previous studies have revealed that they mediate the intensity of herbivory in other Western Atlantic marshes. Neither nutrient enrichment nor experimental disturbances affected crab grazing intensity despite their strong effects in other marsh systems. Within and among Cape Cod salt marshes, however, Sesarma burrows are concentrated on peat substrate. Surveys of 10 Cape Cod marshes revealed that burrow density, depth, and complexity are all much higher on peat than on sand or mud substrate, and paralleling these patterns, crab abundance, herbivore pressure, and the expansion of die-off areas are markedly higher on peat than on other substrates. Complementing work hypothesizing that predator release is triggering increased crab herbivory in Cape Cod marshes, these results suggest that cordgrass die-offs are constrained to the peat substrate commonly found on the leading edge of marshes and that the vulnerability of New England salt marshes to crab herbivory and future die-offs may be predictable. PMID:19739373

Bertness, Mark D; Holdredge, Christine; Altieri, Andrew H

2009-08-01

161

Ecohydrology of drought in a tide-dominated salt marsh island  

NASA Astrophysics Data System (ADS)

The importance of groundwater flow for wetland zonation and productivity is particularly striking in salt marsh ecosystems, where tidally-influenced groundwater flow controls salinity in addition to saturation state and nutrient transport. Here we describe complex interactions between groundwater, rainfall, evapotranspiration and surface water in an ostensibly simple salt marsh island that was affected by acute marsh dieback in 2001-2002, during a period of severe drought. Two mechanisms by which drought may cause dieback have been hypothesized: (1) soil drying leads to changes in chemistry (pH and/or redox state) and (2) drought leads to high porewater salinities. In addition to assessing these two hypotheses, a further question at our site is how a dearth of rainfall could affect an island that lacks a freshwater lens and is typically inundated by saline surface water twice a day. We instrumented the marsh with a network of piezometers and diffusion samplers in 2006. Hydrologic monitoring revealed rare periods when the marsh was not inundated for several consecutive tidal cycles, but no periods with similar low water levels were found in the tidal record prior to the dieback. Thus, soil drying appears unlikely to have been the cause of dieback at our site. Porewater salinity was monitored via a combination of piezometers and diffusion samplers. We found striking variations in salinity (14 - 40 ppt) in the upper 1 m of the marsh mud, but nearly constant salinity (36 ppt) at depths greater than 1 m. These results suggest significant infiltration of fresh rainwater, despite frequent inundation by surface water, with subsequent increases in salinity via transpiration as water moves downward through the root zone. Simple statistical models suggest that porewater salinity is correlated with surface water salinity and rainfall over periods of 30-60 days, but these models fail to capture the full range of variability in this complex system. Results also suggest that porewater salinity in the island was much higher during the drought of 2001-2002 than it was during the period we monitored, so that hypersaline conditions likely developed. These results can be used to inform process-based numerical models, which in turn can be used to develop quantitative estimates of the timing and duration of hypersaline conditions during the drought.

Hughes, A. L.; Wilson, A. M.; Morris, J. T.

2010-12-01

162

Shoreline Development Drives Invasion of Phragmites australis and the Loss of Plant Diversity on New England Salt Marshes  

Microsoft Academic Search

The reed Phragmites australis Cav. is aggressively invading salt marshes along the Atlantic Coast of North America. We examined the interactive role of habitat alteration (i.e., shoreline development) in driv- ing this invasion and its consequences for plant richness in New England salt marshes. We surveyed 22 salt marshes in Narragansett Bay, Rhode Island, and quantified shoreline development, Phragmites cover,

BRIAN R. SILLIMAN; MARK D. BERTNESS

2004-01-01

163

Suitability of different salt marsh plants for petroleum hydrocarbons remediation.  

PubMed

The suitability of the salt-marsh species Halimione portulacoides, Scirpus maritimus, Juncus maritimus and an association of the last two for remediation of petroleum hydrocarbons (PHC) in soil was investigated. An outdoor laboratory experiment (microcosm-scale) was carried out using contaminated soil collected in a refinery, as a complement of another study carried out in the refinery environment (mesocosm-scale). Soil samples with old contamination (mainly crude oil) and with a mixture of the old and recent (turbine oil) contamination were tested. Studies in both micro- and mesocosm-scale provided results coherent in substance. The presence of S. maritimus caused removal of old contamination which was refractory to natural attenuation (after 7months of exposure, efficiency was 13% when only old contamination was present and 40% when the soil also contained recent contamination). H. portulacoides (only included in the microcosm-scale study) revealed also potentiality for PHC remediation, although with less efficiency than S. maritimus. Degradation of recent contamination was also faster in the presence of plants (after 7months: 100% in the presence of S. maritimus vs. 63% in its absence). As these species are common in salt marsh areas in Atlantic coast of Europe, it is probable they will be also useful for recovering coast sediments. In contrast, J. maritimus and association did not reveal capability to remove PHC from soil, the presence of J. maritimus inhibiting the capability of S. maritimus. PMID:21601235

Couto, M Nazaré P F S; Basto, M Clara P; Vasconcelos, M Teresa S D

2011-05-20

164

White phosphorus poisoning of waterfowl in an Alaskan salt marsh.  

PubMed

The cause of the yearly death of an estimated 1,000 to 2,000 migrating dabbling ducks (Anas spp.) and 10 to 50 swans (Cygnus buccinator and C. columbianus) has remained a mystery for the last ten years in Eagle River Flats (ERF), a 1,000 ha estuarine salt marsh near Anchorage, Alaska, used for artillery training by the U.S. Army. We have gathered evidence that the cause of this mortality is the highly toxic, incendiary munition white phosphorus (P4). The symptoms of poisoning we observed in wild ducks included lethargy, repeated drinking, and head shaking and rolling. Death was preceded by convulsions. Farm-reared mallards dosed with white phosphorus showed nearly identical behavioral symptoms to those of wild ducks that became sick in ERF. White phosphorus does not occur in nature but was found in both the sediments where dabbling ducks and swans feed and in the gizzards of all carcasses collected in ERF. We hypothesize that feeding waterfowl are ingesting small particles of the highly toxic, incendiary munition P4 stored in the bottom anoxic sediments of shallow salt marsh ponds. PMID:1474672

Racine, C H; Walsh, M E; Roebuck, B D; Collins, C M; Calkins, D; Reitsma, L; Buchli, P; Goldfarb, G

1992-10-01

165

Seasonal habitat-use patterns of nekton in a tide-restricted and unrestricted New England salt marsh  

USGS Publications Warehouse

Many New England salt marshes remain tide-restricted or are undergoing tidal restoration. Hydrologic manipulation of salt marshes affects marsh biogeochemistry and vegetation patterns, but responses by fishes and decapod crustaceans (nekton) remain unclear, This study examines nekton habitat-use patterns in the tide-restricted Hatches Harbor salt marsh (Provincetown, Massachusetts) relative to a downstream, unrestricted marsh. Nekton assemblages were sampled in tidal creek, marsh pool, and salt marsh surface habitats. Pools and creeks were sampled every two weeks for one year to account for seasonal variability, and the marsh surface was sampled at two-week intervals in summer and fall. Density, richness, and community composition of nekton in creek and marsh surface habitats were similar between the unrestricted and restricted marsh, but use of pools differed drastically on the two sides of the tide-restricting dike. In 95% of the cases tested, restricted marsh habitats provided equal or greater habitat value for nekton than the same habitat in the unrestricted marsh (based on density), suggesting that the restricted marsh did not provide a degraded habitat for most species. For some species, the restricted marsh provided nursery, breeding, and overwintering habitat during different seasons, and tidal restoration of this salt marsh must be approached with care to prevent losses of these valuable marsh functions.

Raposa, K.B.; Roman, C.T.

2001-01-01

166

Phylogenetic analysis of culturable dimethyl sulfide-producing bacteria from a spartina-dominated salt marsh and estuarine water.  

PubMed

Dimethylsulfoniopropionate (DMSP), an abundant osmoprotectant found in marine algae and salt marsh cordgrass, can be metabolized to dimethyl sulfide (DMS) and acrylate by microbes having the enzyme DMSP lyase. A suite of DMS-producing bacteria isolated from a salt marsh and adjacent estuarine water on DMSP agar plates differed markedly from the pelagic strains currently in culture. While many of the salt marsh and estuarine isolates produced DMS and methanethiol from methionine and dimethyl sulfoxide, none appeared to be capable of producing both methanethiol and DMS from DMSP. DMSP, and its degradation products acrylate and beta-hydroxypropionate but not methyl-3-mecaptopropionate or 3-mercaptopropionate, served as a carbon source for the growth of all the alpha- and beta- but only some of the gamma-proteobacterium isolates. Phylogenetic analysis of 16S rRNA gene sequences showed that all of the isolates were in the group Proteobacteria, with most of them belonging to the alpha and gamma subclasses. Only one isolate was identified as a beta-proteobacterium, and it had >98% 16S rRNA sequence homology with a terrestrial species of Alcaligenes faecalis. Although bacterial population analysis based on culturability has its limitations, bacteria from the alpha and gamma subclasses of the Proteobacteria were the dominant DMS producers isolated from salt marsh sediments and estuaries, with the gamma subclass representing 80% of the isolates. The alpha-proteobacterium isolates were all in the Roseobacter subgroup, while many of the gamma-proteobacteria were closely related to the pseudomonads; others were phylogenetically related to Marinomonas, Psychrobacter, or Vibrio species. These data suggest that DMSP cleavage to DMS and acrylate is a characteristic widely distributed among different phylotypes in the salt marsh-estuarine ecosystem. PMID:11229912

Ansede, J H; Friedman, R; Yoch, D C

2001-03-01

167

Phylogenetic Analysis of Culturable Dimethyl Sulfide-Producing Bacteria from a Spartina-Dominated Salt Marsh and Estuarine Water  

PubMed Central

Dimethylsulfoniopropionate (DMSP), an abundant osmoprotectant found in marine algae and salt marsh cordgrass, can be metabolized to dimethyl sulfide (DMS) and acrylate by microbes having the enzyme DMSP lyase. A suite of DMS-producing bacteria isolated from a salt marsh and adjacent estuarine water on DMSP agar plates differed markedly from the pelagic strains currently in culture. While many of the salt marsh and estuarine isolates produced DMS and methanethiol from methionine and dimethyl sulfoxide, none appeared to be capable of producing both methanethiol and DMS from DMSP. DMSP, and its degradation products acrylate and ?-hydroxypropionate but not methyl-3-mecaptopropionate or 3-mercaptopropionate, served as a carbon source for the growth of all the ?- and ?- but only some of the ?-proteobacterium isolates. Phylogenetic analysis of 16S rRNA gene sequences showed that all of the isolates were in the group Proteobacteria, with most of them belonging to the ? and ? subclasses. Only one isolate was identified as a ?-proteobacterium, and it had >98% 16S rRNA sequence homology with a terrestrial species of Alcaligenes faecalis. Although bacterial population analysis based on culturability has its limitations, bacteria from the ? and ? subclasses of the Proteobacteria were the dominant DMS producers isolated from salt marsh sediments and estuaries, with the ? subclass representing 80% of the isolates. The ?-proteobacterium isolates were all in the Roseobacter subgroup, while many of the ?-proteobacteria were closely related to the pseudomonads; others were phylogenetically related to Marinomonas, Psychrobacter, or Vibrio species. These data suggest that DMSP cleavage to DMS and acrylate is a characteristic widely distributed among different phylotypes in the salt marsh-estuarine ecosystem.

Ansede, John H.; Friedman, Robert; Yoch, Duane C.

2001-01-01

168

Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise  

PubMed Central

The distribution of New England salt marsh communities is intrinsically linked to the magnitude, frequency, and duration of tidal inundation. Cordgrass (Spartina alterniflora) exclusively inhabits the frequently flooded lower elevations, whereas a mosaic of marsh hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus gerardi) typically dominate higher elevations. Monitoring plant zonal boundaries in two New England salt marshes revealed that low-marsh cordgrass rapidly moved landward at the expense of higher-marsh species between 1995 and 1998. Plant macrofossils from sediment cores across modern plant community boundaries provided a 2,500-year record of marsh community composition and documented the migration of cordgrass into the high marsh. Isotopic dating revealed that the initiation of cordgrass migration occurred in the late 19th century and continued through the 20th century. The timing of the initiation of cordgrass migration is coincident with an acceleration in the rate of sea-level rise recorded by the New York tide gauge. These results suggest that increased flooding associated with accelerating rates of sea-level rise has stressed high-marsh communities and promoted landward migration of cordgrass. If current rates of sea-level rise continue or increase slightly over the next century, New England salt marshes will be dominated by cordgrass. If climate warming causes sea-level rise rates to increase significantly over the next century, these cordgrass-dominated marshes will likely drown, resulting in extensive losses of coastal wetlands.

Donnelly, Jeffrey P.; Bertness, Mark D.

2001-01-01

169

Relationships between sedimentation, plant species, and the proximity to tidal channels in coastal salt marshes  

NASA Astrophysics Data System (ADS)

Deposition of sediment on vegetated salt marshes enables these marshes to maintain their elevation relative to rising sea level. It has been found that deposition rates of suspended sediment on vegetated salt marshes are highest near tidal channels. This is due to the reduction in turbulence as flows from the tidal channel encounter the stems of the macrophytes that live on the marsh. Despite the presence of levees along some tidal channels, many marsh surfaces paradoxically slope gently upward away from tidal creeks, despite the reduction of deposition of suspended sediment distal from the salt marsh creek. We explore the effect of different marsh species on deposition rates in order to explain this apparent paradox. In the Beaufort Inlet, North Carolina, Spartina alterniflora tends to grow at low elevations near tidal channels, whereas Juncus roemerianus occupies higher elevations distal from the tidal channels. Juncus roemerianus tends to have greater biomass and stem density; this causes it to be more effective at trapping suspended sediment, and may lead Juncus roemerianus to have a higher rate of organogenic sedimentation compared to Spartina alterniflora. We explore how these two effects may allow the portion of the marsh populated by Juncus roemerianus to remain at a higher elevation than the portion of the marsh occupied by Spartina alterniflora, despite the greater rate of deposition due to the settling of suspended sediment in portions of the marsh near the tidal channels.

Mudd, S. M.; Howell, S. M.; Furbish, D. J.; Morris, J. T.

2006-12-01

170

The ecology of New England high salt marshes: A community profile  

SciTech Connect

The high salt marshes of New England have evolved in response to sea-level rises through accretion of sediments entrapped by marsh vegetation. Early theories of marsh development are traced and are reconciled in Redfield's synthesis accounting for marsh growth by aggradation over sand and mud flats as well as by accretion on existing marsh surfaces. The shape and appearance of high marshes result from unique, complex interactions of local topography and bathymetry, sea-level rise, tides, sediment supply and vegetation. These factors, particularly the major influences of tides and short-term changes in sea-level, are incorporated in short-term processes that define and mold the ecology of the high marsh. Short- and long-term mechanisms have produced approximate zonation of vegetation in the high marsh. High marshes are contrasted to Spartina-dominated low marsh in terms of plant and animal species and the relative importance of the dynamics of production, export, decomposition, and accumulation of materials in the sediments. High marshes have been subjected to man's activities since earliest English settlement. This history of New Englanders' impact on this community is traced from their use of marshes as hay fields to depositories of pollutants. Habitat management considerations today include mosquito control and sewage sludge treatment. 154 refs., 29 figs., 14 tabs.

Nixon, S.W. (Rhode Island Univ., Kingston, RI (USA). Graduate School of Oceanography)

1982-03-01

171

Microbial carbon monoxide consumption in salt marsh sediments.  

PubMed

We have examined sediments from a fringing salt marsh in Maine to further understand marine CO metabolism, about which relatively little is known. Intact cores from the marsh emitted CO during dark oxic incubations, but emission rates were significantly higher during anoxic incubations, which provided evidence for simultaneous production and aerobic consumption in surface sediments. CO emission rates were also elevated when cores were exposed to light, which indicated that photochemical reactions play a role in CO production. A kinetic analysis of marsh surface sediments yielded an apparent K(m) of about 82 ppm, which exceeded values reported for well-aerated soils that consume atmospheric CO (65nM). Surface (0-0.2 cm depth interval) sediment slurries incubated under oxic conditions rapidly consumed CO, and methyl fluoride did not inhibit uptake, which indicated that neither ammonia nor methane oxidizers contributed to the observed activity. In contrast, aerobic CO uptake was inhibited by additions of readily available organic substrates (pyruvate, glucose and glycine), but not by cellulose. CO was also consumed by surface and sub-surface sediment slurries incubated under anaerobic conditions, but rates were less than during aerobic incubations. Molybdate and nitrate or nitrite, but not 2-bromoethanesulfonic acid, partially inhibited anaerobic uptake. These results suggest that sulfidogens and acetogens, but not dissimilatory nitrate reducers or methanogens, actively consume CO. Sediment-free plant roots also oxidized CO aerobically; rates for Spartina patens and Limonium carolinianum roots were significantly higher than rates for Spartina alterniflora roots. Thus plants may also impact CO cycling in estuarine environments. PMID:17059484

King, Gary M

2006-10-24

172

Tidal Flushing Restores the Physiological Condition of Fish Residing in Degraded Salt Marshes  

PubMed Central

Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus) at four tidally restricted and four tidally restored marshes in New England invaded by P. australis relative to adjacent reference salt marshes. We used physiological and morphological indicators of fish condition, including proximate body composition (% lipid, % lean dry, % water), recent daily growth rate, age class distributions, parasite prevalence, female gravidity status, length-weight regressions, and a common morphological indicator (Fulton’s K) to assess impacts to fish health. We detected a significant increase in the quantity of parasites infecting fish in tidally restricted marshes but not in those where tidal flow was restored to reduce P. australis cover. Using fish length as a covariate, we found that unparasitized, non-gravid F. heteroclitus in tidally restricted marshes had significantly reduced lipid reserves and increased lean dry (structural) mass relative to fish residing in reference marshes. Fish in tidally restored marshes were equivalent across all metrics relative to those in reference marshes indicating that habitat quality was restored via increased tidal flushing. Reference marshes adjacent to tidally restored sites contained the highest abundance of young fish (ages 0–1) while tidally restricted marshes contained the lowest. Results indicate that F. heteroclitus residing in physically and hydrologically altered marshes are at a disadvantage relative to fish in reference marshes but the effects can be reversed through ecological restoration.

Dibble, Kimberly L.; Meyerson, Laura A.

2012-01-01

173

Monitoring food web changes in tide-restored salt marshes: A carbon stable isotope approach  

Microsoft Academic Search

Primary producer (angiosperms, macroalgae, submerged aquatic vegetation), suspended particulate matter, andFundulus heteroclitus isotope values (?13C, ?15N, ?34S) were examined to assess their use as indicators for changes in food web support functions in tidally-restored salt marshes.\\u000a Study sites, located throughout the southern New England region (USA), ranged fromSpartina alterniflora-dominated reference marshes, marshes under various regimes and histories of tide restoration,

Andrew S. Wozniak; Charles T. Roman; Sam C. Wainright; Richard A. McKinney; Mary-Jane James-Pirri

2006-01-01

174

Distribution and ecological role of the non-native macroalga Gracilaria vermiculophylla in Virginia salt marshes  

Microsoft Academic Search

Intertidal salt marshes are considered harsh habitats where relatively few stress-resistant species survive. Most studies\\u000a on non-native species in marshes describe terrestrial angiosperms. We document that a non-native marine macroalga, Gracilaria vermiculophylla, is abundant throughout Virginia’s Atlantic coastline. We sampled eight marshes, characterized by low slopes and by the presence\\u000a of the tube-building polychaete Diopatra\\u000a cuprea on adjacent mudflats, which

M. S. Thomsen; K. J. McGlathery; A. Schwarzschild; B. R. Silliman

2009-01-01

175

Predaceous gastropods regulate new-shell supply to salt marsh hermit crabs  

Microsoft Academic Search

Marsh hermit crabsPagurus longicarpus Say directly acquire new shells as the predatory gastropodMelongena corona Gmelin consumes marsh periwinkles,Littorina irrorata Say. The influx rate of new shells into a salt marsh hermit crab population was measured by marking live periwinkles and daily recovering the shells from hermit crabs over periods of 3 to 6 d. Average rates of new shell acquisition

T. Payson Wilber; W. F. Herrnkind

1984-01-01

176

How sea level rise affects sedimentation, plant growth, and carbon accumulation on coastal salt marshes  

NASA Astrophysics Data System (ADS)

The rate of accretion on coastal salt marshes depends on feedbacks between flow, macrophyte growth, and sedimentation. Under favourable conditions, marsh accretion rates will keep pace with the local rate of sea level rise. Marsh accretion is driven by both organic and inorganic sedimentation; mineral rich marshes will need less organic sedimentation to keep pace with sea level rise. Here we use a numerical model of marsh accretion, calibrated by sediment cores, to explore the relationship between sea level rise and carbon sequestration on salt marshes in the face of differing supplies of inorganic sediment. The model predicts that changes in carbon storage resulting from changing sediment supply or sea-level rise are strongly dependant on the background sediment supply: if inorganic sediment supply is reduced in an already sediment poor marsh the storage of organic carbon will increase to a far greater extent than in a sediment-rich marsh, provided that the rate of sea-level rise does not exceed a threshold. These results imply that altering sediment supply to estuaries (e.g., by damming upstream rivers or altering littoral sediment transport) could lead to significant changes in the carbon budgets of coastal salt marshes.

Mudd, S. M.; Howell, S. M.; Morris, J. T.

2009-12-01

177

Latitudinal variation in herbivore pressure in Atlantic Coast salt marshes.  

PubMed

Despite long-standing interest in latitudinal variation in ecological patterns and processes, there is to date weak and conflicting evidence that herbivore pressure varies with latitude. We used three approaches to examine latitudinal variation in herbivore pressure in Atlantic Coast salt marshes, focusing on five abundant plant taxa: the grass Spartina alterniflora, the congeneric rushes Juncus gerardii and J. roemerianus, the forb Solidago sempervirens, and the shrubs Iva frutescens and Baccharis halimifolia. Herbivore counts indicated that chewing and gall-making herbivores were typically > or = 10 times more abundant at low-latitude sites than at high-latitude sites, but sucking herbivores did not show a clear pattern. For two herbivore taxa (snails and tettigoniid grasshoppers), correctly interpreting latitudinal patterns required an understanding of the feeding ecology of the species, because the species common at high latitudes did not feed heavily on plant leaves whereas the related species common at low latitudes did. Damage to plants from chewing herbivores was 2-10 times greater at low-latitude sites than at high-latitude sites. Damage to transplanted "phytometer" plants was 100 times greater for plants transplanted to low- than to high-latitude sites, and two to three times greater for plants originating from high- vs. low-latitude sites. Taken together, these results provide compelling evidence that pressure from chewing and gall-making herbivores is greater at low vs. high latitudes in Atlantic Coast salt marshes. Sucking herbivores do not show this pattern and deserve greater study. Selective pressure due to greater herbivore damage at low latitudes is likely to partially explain documented patterns of low plant palatability to chewing herbivores and greater plant defenses at low latitudes, but other factors may also play a role in mediating these geographic patterns. PMID:19294924

Pennings, Steven C; Ho, Chuan-Kai; Salgado, Cristiano S; Wieski, Kazimierz; Davé, Nilam; Kunza, Amy E; Wason, Elizabeth L

2009-01-01

178

Mosquitoes Associated with Ditch-Plugged and Control Tidal Salt Marshes on the Delmarva Peninsula  

PubMed Central

A study was conducted during the summer of 2009 (from July to September) to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November) ditches were plugged near their outlets in two (‘experimental’) marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557) of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt) than unoccupied habitats (20.1 ppt), and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of this study suggest that wooded areas adjacent to salt marshes may be a substantial source of biting adult mosquitoes usually associated with salt marsh habitats and that ditch plugging may alter the productivity of mosquitoes on some marshes. We recommend future studies consider mosquito productivity from habitats surrounding salt marshes, and if assessments of marsh alterations are a goal, compare multiple experimental and control areas before and after treatments to determine if alterations have a consistent impact on regional mosquito production.

Leisnham, Paul T.; Sandoval-Mohapatra, Sarah

2011-01-01

179

Marine fungal diversity: a comparison of natural and created salt marshes of the north-central Gulf of Mexico.  

PubMed

Marine fungal communities of created salt marshes of differing ages were compared with those of two reference natural salt marshes. Marine fungi occurring on the lower 30 cm of salt marsh plants Spartina alterniflora and Juncus roemerianus were inventoried with morphological and molecular methods (ITS T-RFLP analysis) to determine fungal species richness, relative frequency of occurrence and ascomata density. The resulting profiles revealed similar fungal communities in natural salt marshes and created salt marshes 3 y old and older with a 1.5 y old created marsh showing less fungal colonization. A 26 y old created salt marsh consistently exhibited the highest fungal species richness. Ascomata density of the dominant fungal species on each host was significantly higher in natural marshes than in created marshes at all three sampling dates. This study indicates marine fungal saprotroph communities are present in these manmade coastal salt marshes as early as 1 y after marsh creation. The lower regions of both plant hosts were dominated by a small number of marine ascomycete species consistent with those species previously reported from salt marshes of the East Coast of USA. PMID:20524584

Walker, Allison K; Campbell, Jinx

180

Utilization of Open Marsh Water Management Ditches by the Treatened Atlantic Salt Marsh Snake ('Nerodia clarkii taeniata').  

National Technical Information Service (NTIS)

A survey of a population of Atlantic salt marsh snakes (Nerodia clarkii taeniata) located in a recovered mosquito control impoundment was made during a 6 month period beginning in July, 1991, and ending in early January 1992. Snakes were either hand caugh...

G. T. Goode S. A. Scott H. I. Kochman

1992-01-01

181

The fate of metals introduced into a new england salt marsh  

Microsoft Academic Search

As part of a study to investigate the effect of chronic eutrophication on salt marshes, a sewage sludge fertilizer has been applied to experimental plots in Great Sippewissett Marsh, MA., since 1974. The fertilizer contains substantial amounts of heavy metals. Sediments from fertilized plots contain elevated levels of Cu, Cd, Zn, Fe, Mn, Cr, and Pb. The above- and below-ground

Anne E. Giblin; Ivan Valiela; John M. Teal

1983-01-01

182

RELATIONSHIPS OF NITROGEN LOADINGS AND PHYSICAL CHARACTERISTICS WITH PLANT STRUCTURE IN NEW ENGLAND SALT MARSHES  

EPA Science Inventory

Nitrogen enrichment is hypothesized to cause competitive displacement of dominant plants in New England salt marshes. In this Narragansett Bay, RI, field survey, we examined the vascular plant species richness and the extent, density, and height of Spartina species in ten marshe...

183

Effects of grazing and inundation on pasture quality and seed production in a salt marsh  

Microsoft Academic Search

During a six-year period, changes in the composition of dominant plant species of importance to foraging birds in a salt marsh on the Swedish west coast were followed inside and outside exclosures to document effects of grazing on herbage quality and seed production. Since marshes provide an important habitat for foraging geese and ducks, it was of interest to determine

Olof Pehrsson

1988-01-01

184

Salt marsh sediment bacteria: their distribution and response to external nutrient inputs.  

PubMed

A primary focus among microbial ecologists in recent years has been to understand controls on the distribution of microorganisms in various habitats. Much less attention has been paid to the way that environmental disturbance interacts with processes that regulate bacterial community composition. We determined how human disturbance affected the distribution and community structure of salt marsh sediment bacteria by using denaturing gradient gel electrophoresis of 16S rRNA in five different habitats in each of four salt marshes located in northeastern Massachusetts, USA. Two of the four marsh creeks were experimentally enriched 15 x above background by the addition of nitrogen and phosphorus fertilizers for two or more growing seasons. Our results indicate that extrinsic factors acting at broad scales do not influence the distribution of salt marsh sediment bacteria. Intrinsic factors, controlled by local-scale environmental heterogeneity, do play a role in structuring these sediment microbial communities, although nutrient enrichment did not have a consequential effect on the microbial community in most marsh habitats. Only in one habitat, a region of the marsh creek wall that is heavily colonized by filamentous algae, did we see any effect of fertilization on the microbial community structure. When similar habitats were compared among marshes, there was considerable convergence in the microbial community composition during the growing season. Environmental factors that correlated best with microbial community composition varied with habitat, suggesting that habitat-specific intrinsic forces are primarily responsible for maintaining microbial diversity in salt marsh sediments. PMID:19421233

Bowen, Jennifer L; Crump, Byron C; Deegan, Linda A; Hobbie, John E

2009-05-07

185

Linkages Between Salt Marshes and Other Nekton Habitats in Delaware Bay, USA  

Microsoft Academic Search

Although the importance of salt marsh habitats for fishes and crabs has been accepted for nearly a half century, the linkages between marshes and adjacent estuarine habitats have been ill-defined. In this synoptic study (n > 19,000 samples, 14 species, 10 million individuals), we provide fresh insights into the patterns of fish and blue crab habitat use for the Delaware

Kenneth W. Able; John H. Balletto; Stacy M. Hagan; Paul R. Jivoff; Kenneth Strait

2007-01-01

186

The Role of Tidal Salt Marsh as an Energy Source for  

Microsoft Academic Search

Stable isotope ratios of carbon, nitrogen, and sulfur (813C, 815N, and 834S) in bay anchovy Anchoa mitchilli and white perch Morone americana from Delaware Bay were a function of capture location and, for restored tidal salt marshes, possibly a function of the relative position of the marsh restoration trajectory. White perch collected in polyhaline restoration and reference (Moore's Beach) sites

KEITH L. BOSLEY; CHARLOTTE M. FULLER; SAM C. WAINRIGHT; MICHAEL P. WEINSTEIN; STEVEN Y. LITVIN

2000-01-01

187

The macrobenthos in Spartina alterniflora salt marshes of the Wanggang tidal-flat, Jiangsu coast, China  

Microsoft Academic Search

On the Jiangsu coast, eastern China, Spartina alterniflora, which was introduced artificially into the region, is becoming a dominant plant species in the inter-tidal salt marshes. In order to evaluate the environmental and ecological impact of the colonization of S. alterniflora, we carried out investigations into the benthic macrofauna of the Spartina marshes of the Wanggang area, central Jiangsu coast,

Wen-jing Xie; Shu Gao

2009-01-01

188

Dissolved phosphorus concentrations in a natural salt-marsh of Delaware  

Microsoft Academic Search

Dissolved phosphorus concentrations, salinity, pH, and related physical parameters were used to evaluate the variations in a natural salt-marsh. Diel, tidal, lunar, and seasonal variations in phosphorus concentrations were evaluated for a three year period in a natural marsh, situated along the southwestern coast of the Delaware Estuary.

Robert J. Reimold; Franklin C. Daiber

1970-01-01

189

Biostimulation For The Treatment Of An Oil-Contaminated Coastal Salt Marsh  

EPA Science Inventory

A field study was conducted on a coastal salt marsh in Nova Scotia, Canada, during the summer of 2000. The objective of the study was to assess the effectiveness of biostimulation in restoring an oil-contaminated coastal marsh dominated by Spartina alterniflora under north...

190

Early diagenesis of lignin-associated phenolics in the salt marsh grass Spartina alterniflora  

Microsoft Academic Search

The predepositional stability of lignin in the salt marsh cordgrass Spartina alterniflora was examined in two different degradation studies: one was a traditional litterbag study carried out using post-senescent brown leaves in a North Carolina marsh creek, and the other was a study in which senescing, standing plants were tagged and allowed to undergo in situ degradation in a Sapelo

R. I. Haddad; C. S. Martens; S. Y. Newell; R. D. Fallon

1992-01-01

191

Evaluation of tidal marsh restoration: Comparison of selected macroinvertebrate populations on a restored impounded valley marsh and an unimpounded valley marsh within the same salt marsh system in Connecticut, USA  

NASA Astrophysics Data System (ADS)

Macroinvertebrates were examined on an impounded valley marsh in Stonington, Connecticut, that has changed from a Typha-dominated system to one with typical salt-marsh vegetation during 13 years following the reintroduction of tidal exchange. Animal populations on this restored impounded marsh were evaluated by comparing them with populations on a nearby unimpounded valley marsh of roughly the same size. Populations of the high marsh snail, Melampus bidentatus Say, were quantitatively sampled along transects that extended from the water-marsh edge to the upland; those of the ribbed mussel, Geukensia demissa Dillwyn, were sampled in low marsh areas on transects along the banks of creeks and mosquito ditches. The occurrence of other marsh invertebrates also was documented, but their abundance was not measured. The mean density of Melampus was 332±39.6 SE/m2 on the restored impounded marsh and 712±56.0 SE/m2 on the unimpounded marsh. However, since snails were larger on the restored impounded marsh, the difference in snail biomass was less pronounced than the difference in snail density. Mean Melampus biomass was 4.96±0.52 SE g dry wt/m2 on the restored impounded marsh and 6.96±0.52 SE g dry wt/m2 on the unimpounded marsh. On the two marshes, snail density and biomass varied in relation to plant cover and other factors. The density and biomass of Geukensia at the edge of the marsh were comparable on the restored impounded and unimpounded marshes. Mean mussel densities ranged from 80 to 240/m2 and mean mussel biomass varied from 24.8-64.8 g dry wt/m2 in different low marsh areas. In contrast, below the impoundment dike, mean Geukensia density was 1100±96.4 SE/m2 and mean Geukensia biomass was 303.6±33.28 SE g dry wt/m2. A consideration of all available evidence leads to the conclusion that the impounded marsh is in an advanced phase of restoration.

Peck, Myron A.; Fell, Paul E.; Allen, Elizabeth A.; Gieg, Jennifer A.; Guthke, Carl R.; Newkirk, Michael D.

1994-03-01

192

Sulfate reduction in a New England salt marsh  

Microsoft Academic Search

Sulfate reduction rates were measured for 2 years in the peat of a salt mars by a radiotracer technique. Rates are high throughout the peat, from the surface to more than 20 cm deep. The integrated annual rate is about 75 mol SOâ\\/sup 2 -\\/.m⁻².yr⁻¹, the highest yet reported for any natural ecosystem. Sulfate reduction accounts for the consumption of

ROBERT W. HOWARTH; JOHN M. TEAL

1979-01-01

193

Flow, sedimentation, and biomass production on a vegetated salt marsh in South Carolina: toward a predictive model of marsh morphologic and ecologic evolution  

NASA Astrophysics Data System (ADS)

A 1-D model for exploring the interaction between hydrodynamics, sedimentation, and plant community evolution on a salt marsh populated by Spartina alterniflora is developed. In the model tidally induced flows over marsh platforms are affected by S. alterniflora through drag forces. In general macrophyte characteristics are determined by a wide range of processes; here, based on field studies at North Inlet estuary, South Carolina, the biomass of the S. alterniflora on the marsh platform is simply related to their time of submergence under tidally induced flows. Additionally, field data collected at North Inlet are used to relate biomass to plant area per unit volume, stem diameter, and an empirical drag coefficient. Sedimentation is also related to biomass, through either organogenic deposition or trapping of suspended sediment particles. The morphologic evolution of simulated marshes is explored by varying the sedimentation process and the rate of sea level rise. Different sedimentation processes result in marshes with different morphologies. An organogenic marsh is predicted to evolve under a regime of steady sea level rise into a platform with a relatively flat surface, whereas a marsh developed primarily through a trapping mechanism is predicted to have a surface that slopes gently away from the salt marsh creek. As predicted by 0-D modeling studies, sea level rise may be accommodated up to a certain critical sea level rise rate, after which the salt marsh platform will drown. Marshes that accrete through sediment trapping adjust to changes in sea level more rapidly than marshes that accrete through organogenic deposition.

Fagherazzi, S.; Mudd, S. M.; Morris, J. T.; Furbish, D. J.

2004-12-01

194

DENITRIFICATION IN FRINGING SALT MARSHES OF NARRAGANSETT BAY, RHODE ISLAND, USA  

EPA Science Inventory

In the past century, loading of terrestrial inorganic nitrogen to coastal receiving waters has increased dramatically. Salt marshes, because of their location between upland regions and coastal waters and their recognized role as nutrient transformers, have the potential to ameli...

195

Rhode Island Salt Marshes: Elevation Capital and Resilience to Sea Level Rise  

EPA Science Inventory

Tidal salt marsh is especially sensitive to deterioration due to the effects of accelerated sea level rise when combined with other anthropogenically linked stressors, including crab herbivory, changes in tidal hydrology, nutrient loading, dam construction, changes in temperature...

196

The ecology of regularly flooded salt marshes of New England: A community profile  

SciTech Connect

The current state-of-the-art in scientific knowledge about intertidal salt marshes is presented, but restricted to one habitat in New England, specifically Great Sippewissett at Falmouth, Massachusetts. (PSB)

Teal, J.M.

1986-06-01

197

Predicting Phosphorus Movement and Pesticide Action in Salt Marshes with Microecosystems.  

National Technical Information Service (NTIS)

Microecosystems of a salt marsh community were designed and established to determine the mechanism by which phosphorous moves through the different physical and biological components of the community, and to determine the effect of the herbicide, fluometu...

J. W. Everest

1978-01-01

198

Ecology of Irregularly Flooded Salt Marshes of the Northeastern Gulf of Mexico: A Community Profile.  

National Technical Information Service (NTIS)

The salt marshes of the northeastern Gulf of Mexico are distinguished by irregular flooding, low energy wave and tidal action, and long periods of exposure. The plant community is most often dominated by black needlerush (Juncus roemerianus), the species ...

J. P. Stout

1984-01-01

199

Species Composition, Standing Stock, and Net Primary Production of a Salt Marsh Community in Mississippi.  

National Technical Information Service (NTIS)

Square meter quadrat samples harvested monthly during 1971 to 1972 provided data on the species composition, standing stock, and net primary aerial production of a salt marsh community in St. Louis Bay Estuary, Mississippi. Although a total of 34 species ...

B. C. Gabriel A. A. de la Cruz

1974-01-01

200

Underground Biomass Dynamics and Substrate Selective Properties of Atlantic Coastal Salt Marsh Plants.  

National Technical Information Service (NTIS)

An intensive study was made of the dynamics of the underground portion of selected salt marsh plants along the U. S. Atlantic Coast. The plants studied included: Borrichia frutescens, Carex paleacea, Distichlis spicata, Eleocharis obtusa, Juncus gerardi J...

J. L. Gallagher F. G. Plumley P. L. Wolf

1977-01-01

201

Sulfate Reduction and Other Sedimentary Biogeochemistry in a Northern New England Salt Marsh.  

National Technical Information Service (NTIS)

Sulfate reduction rates, dissolved iron and sulfide concentrations, and titration alkalinity were measured in salt marsh soils along a transect that included areas inhabited by both the tall and short forms of Spartina alterniflora and by Spartina patens....

M. E. Hines S. L. Knollmeyer J. B. Tugel

1992-01-01

202

A Volumetric Analysis of Holocene Sediments Underlying Present Delaware Salt Marshes Inundated by Delaware Bay Tides.  

National Technical Information Service (NTIS)

Data from 226 borings drilled in Delaware salt marshes lying between Wilmington, New Castle County and Lewes, Sussex County were used to construct isopach maps of Holocene muds. Planimetric analyses of these maps and studies of drill records provided info...

A. Richter

1974-01-01

203

Tidal salt marsh sediment in California, USA. Part 2: occurrence and anthropogenic input of trace metals.  

PubMed

Surface sediment samples (0-5 cm) from 5 tidal salt marshes along the coast in California, USA were analyzed to investigate the occurrence and anthropogenic input of trace metals. Among study areas, Stege Marsh located in the central San Francisco Bay was the most contaminated marsh. Concentrations of metals in Stege Marsh sediments were higher than San Francisco Bay ambient levels. Zinc (55.3-744 microg g(-1)) was the most abundant trace metal and was followed by lead (26.6-273 microg g(-1)). Aluminum normalized enrichment factors revealed that lead was the most anthropogenically impacted metal in all marshes. Enrichment factors of lead in Stege Marsh ranged from 8 to 49 (median=16). Sediments from reference marshes also had high enrichment factors (2-8) for lead, indicating that lead contamination is ubiquitous, possibly due to continuous input from atmospherically transported lead that was previously used as a gasoline additive. Copper, silver, and zinc in Stege Marsh were also enriched by anthropogenic input. Though nickel concentrations in Stege Marsh and reference marshes exceeded sediment quality guidelines, enrichment factors indicated nickel from anthropogenic input was negligible. Presence of nickel-rich source rock such as serpentinite in the San Francisco Bay watershed can explain high levels of nickel in this area. Coefficients of variation were significantly different between anthropogenically impacted and non-impacted metals and might be used as a less conservative indicator for anthropogenic input of metals when enrichment factors are not available. PMID:16524617

Hwang, Hyun-Min; Green, Peter G; Higashi, Richard M; Young, Thomas M

2006-03-09

204

Comparison of wetland structural characteristics between created and natural salt marshes in southwest Louisiana, USA  

Microsoft Academic Search

The use of dredge material is a well-known technique for creating or restoring salt marshes that is expected to become more\\u000a common along the Gulf of Mexico coast in the future. However, the effectiveness of this restoration method is still questioned.\\u000a Wetland structural characteristics were compared between four created and three natural salt marshes in southwest Louisiana,\\u000a USA. The created

Keith R. Edwards; C. Edward Proffitt

2003-01-01

205

Dependence of fishery species on salt marshes: The role of food and refuge  

Microsoft Academic Search

Salt marshes are widely believed to serve as nurseries for many fishes and crustaceans of fishery value as a result of the\\u000a high production of vascular plant detritus and the protection from predation offered by shallow, spatially complex habitats.\\u000a Comparisons of the yields of species which reside in salt marsh habitats during critical life history stages (such as penaeid\\u000a shrimp)

Donald F. Boesch; R. Eugene Turner

1984-01-01

206

Salt Marsh Carbon Pool Distribution in a Mid-Atlantic Lagoon, USA: Sea Level Rise Implications  

Microsoft Academic Search

The distribution of carbon (C) within a salt marsh may vary among vegetation zones depending on production and decomposition\\u000a dynamics and organic and mineral depositional history. We examined spatial and temporal variation of plant and soil C pools\\u000a within a salt marsh fringing a coastal lagoon along the mid-Atlantic coast of the U.S. The total plant C pool increased from

Tracy Elsey-Quirk; Denise M. Seliskar; Christopher K. Sommerfield; John L. Gallagher

2011-01-01

207

Environmental and biological controls on methyl halide emissions from southern California coastal salt marshes  

Microsoft Academic Search

Methyl bromide (CH3Br) and methyl chloride(CH3Cl) emission rates from southernCalifornia coastal salt marshes show largespatial and temporal variabilities that arestrongly linked to biological and environmentalfactors. Here we discuss biogeochemical linesof evidence pointing to vegetation as theprimary source of CH3Br and CH3Clemissions from salt marshes. Sediments andmacroalgae do not appear to be major producersof these compounds, based on observations thatthe highest

Robert C. Rhew; Benjamin R. Miller; Markus Bill; Allen H. Goldstein; Ray F. Weiss

2002-01-01

208

Anthropogenic and climate-change impacts on salt marshes of Jamaica Bay, New York City  

Microsoft Academic Search

Field studies and aerial photograph interpretation suggest that large sections of Jamaica Bay salt marshes in New York City\\u000a near John F. Kennedy International Airport are deteriorating rapidly. The relatively recent salt marsh losses may be caused\\u000a by a variety of factors, potentially interacting synergistically. Possible factors include reduced sediment input, dredging\\u000a for navigation channels, boat traffic, and regional sea-level

Ellen Kracauer Hartig; Vivien Gornitz; Alexander Kolker; Frederick Mushacke; David Fallon

2002-01-01

209

A rapid, non-destructive method for estimating aboveground biomass of salt marsh grasses  

Microsoft Academic Search

Understanding the primary productivity of salt marshes requires accurate estimates of biomass. Unfortunately, these estimates\\u000a vary enough within and among salt marshes to require large numbers of replicates if the averages are to be statistically meaningful.\\u000a Large numbers of replicates are rarely taken, however, because they involve too much labor. Here, we present data on a fast,\\u000a non-destructive method for

Glen B. Thursby; Marnita M. Chintala; Denise Stetson; Cathleen Wigand; Denise M. Champlin

2002-01-01

210

Biotic interactions mediate the expansion of black mangrove (Avicennia germinans) into salt marshes under climate change.  

PubMed

Many species are expanding their distributions to higher latitudes due to global warming. Understanding the mechanisms underlying these distribution shifts is critical for better understanding the impacts of climate changes. The climate envelope approach is widely used to model and predict species distribution shifts with changing climates. Biotic interactions between species, however, may also influence species distributions, and a better understanding of biotic interactions could improve predictions based solely on climate envelope models. Along the northern Gulf of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its distribution grows sympatrically with temperate salt marsh plants in Florida, Louisiana, and Texas. In recent decades, freeze-free winters have led to an expansion of black mangrove into salt marshes. We examined how biotic interactions between black mangrove and salt marsh vegetation along the Texas coast varied across (i) a latitudinal gradient (associated with a winter-temperature gradient); (ii) the elevational gradient within each marsh (which creates different marsh habitats); and (iii) different life history stages of black mangroves (seedlings vs. juvenile trees). Each of these variables affected the strength or nature of biotic interactions between black mangrove and salt marsh vegetation: (i) Salt marsh vegetation facilitated black mangrove seedlings at their high-latitude distribution limit, but inhibited black mangrove seedlings at lower latitudes; (ii) mangroves performed well at intermediate elevations, but grew and survived poorly in high- and low-marsh habitats; and (iii) the effect of salt marsh vegetation on black mangroves switched from negative to neutral as black mangroves grew from seedlings into juvenile trees. These results indicate that the expansion of black mangroves is mediated by complex biotic interactions. A better understanding of the impacts of climate change on ecological communities requires incorporating context-dependent biotic interactions into species range models. PMID:23580161

Guo, Hongyu; Zhang, Yihui; Lan, Zhenjiang; Pennings, Steven C

2013-07-15

211

Intertidal variation in foraminiferal species diversity: Mississippi-Louisiana salt marshes  

SciTech Connect

Salt marshes are tide-stressed environments where ecologic variables exert strong selective control upon the distribution, type, and abundance of organisms. Ecologic conditions range from marine to terrestrial; hence gradational and/or abrupt environmental changes across marshes produce similar gradients in communities of organisms and their biotopes. Salt marshes are one of the present-day sites of peat accumulation. They represent a potential millieu for lignite and coal formation. Recognition of microenvironments within such marshes will provide coal explorationists and paleontologists with another tool for predicting the location of subsurface peats, lignites, and coals. Twenty-eight modern bottom samples were collected for analysis for foraminiferal populations (total = live + dead) in the Hancock County, Mississippi, and Pearl River, Louisiana, marshes during May and June 1981. After extracting a minimum of 300 specimens/sample, foraminiferal species diversity patterns among the 14 doubly sampled stations were studied.

Lariccia, M.P.; Krutak, P.R.

1983-03-01

212

A comparison of fungal communities from four salt marsh plants using automated ribosomal intergenic spacer analysis (ARISA).  

PubMed

Fungal decomposers are important contributors to the detritus-based food webs of salt marsh ecosystems. Knowing the composition of salt marsh fungal communities is essential in understanding how detritus processing is affected by changes in community dynamics. Automated ribosomal intergenic spacer analysis (ARISA) was used to examine the composition of fungal communities associated with four temperate salt marsh plants, Spartina alterniflora (short and tall forms), Juncus roemerianus, Distichlis spicata and Sarcocornia perennis. Plant tissues were homogenized and subjected to a particle-filtration protocol that yielded 106 microm particulate fractions, which were used as a source of fungal isolates and fungal DNA. Genera identified from sporulating cultures demonstrated that the 106 microm particles from each host plant were reliable sources of fungal DNA for ARISA. Analysis of ARISA data by principal component analysis (PCA), principal coordinate analysis (PCO) and species diversity comparisons indicated that the fungal communities from the two grasses, S. alterniflora and D. spicata were more similar to each other than they were to the distinct communities associated with J. roemerianus and S. perennis. Principal component analysis also showed no consistent, seasonal pattern in the composition of these fungal communities. Comparisons of ARISA fingerprints from the different fungal communities and those from pure cultures of selected Spartina ascomycetes supported the host/substrate specificity observed for the fungal communities. PMID:17256573

Torzilli, Albert P; Sikaroodi, Masoumeh; Chalkley, David; Gillevet, Patrick M

213

Importance of allochthonous material in benthic macrofaunal community functioning in estuarine salt marshes  

NASA Astrophysics Data System (ADS)

Allochthonous input provides important food and spatial resources for estuarine benthic fauna. While it is known that autochthonous materials are important for fauna occupying small marshes, here, we present the significance of allochthonous materials for benthic fauna inhabiting a large salt marsh. To assess the effects of allochthonous input on benthic macrofaunal communities in estuarine salt marshes, we determined the source of substrate sediments and food resource utilisation patterns of benthic invertebrates in 2 temperate estuaries (the Tama River and the Obitsu River estuarine outlets into Tokyo Bay) by using stable carbon and nitrogen isotope analyses. In the Tama River estuary, which has small patches of marsh vegetation upstream of the river mouth, there was an input of sedimentary organic matter from autochthonous sources (i.e. common reed and microphytobenthos). In the Obitsu River estuary salt marsh, which is situated immediately upstream of the river mouth and is well connected to the sea, sediment consists of allochthonous sources (i.e. imported phytoplankton), along with microphytobenthos. Isotope analysis indicated that most benthic invertebrates in the Tama River estuary depend on benthic microalgae (autochthonous) as a food resource, whereas the macrofauna in the Obitsu River estuary are supported by drift macroalgae (allochthonous), in addition to microphytobenthos or phytoplankton. Our results indicated that allochthonous material provides a food resource and potential habitat for benthic macrofauna in extensive salt marshes that have a strong connection to the sea but is not substantial in smaller marshes with limited connectivity to coastal water.

Kon, Koetsu; Hoshino, Yukihiro; Kanou, Kouki; Okazaki, Daisuke; Nakayama, Satoko; Kohno, Hiroshi

2012-01-01

214

MOSQUITO MAGNETS AS BARRIER TREATMENTS AGAINST SALT MARSH MOSQUITOES AROUND RESIDENTIAL HOUSES IN MARSH AREA  

Technology Transfer Automated Retrieval System (TEKTRAN)

In recent years, more residential homes have been built around the marsh areas located on the Intra-Coastal Waterway (ICW) and brought more complaints about marsh mosquitoes. Many homeowner associations have created policies and regulations that forbid the spraying of pesticides. The new challenge h...

215

Tidal events and salt-marsh structure influence black mangrove (Avicennia germinans) recruitment across an ecotone.  

PubMed

Field experiments were conducted at a black mangrove-salt-marsh ecotone in southwest Florida (U.S.A.) to investigate retention of propagules of the black mangrove, Avicennia germinans, by salt-marsh plants as a mechanism of facilitation operating on recruitment success at landward boundaries. Buoyant A. germinans propagules are dispersed by tides, and stranding is required for establishment; therefore, processes that enable stranding should facilitate mangrove recruitment. We expected the physical structure of salt-marsh vegetation to define propagule retention capacity, and we predicted that salt-marsh plants with distinct growth forms would differentially retain propagules. Experimental monoculture plots (1 m2) of salt-marsh plants with different growth forms (Sporobolus virginicus [grass], Sesuvium portulacastrum [succulent forb], and Batis maritima [succulent scrub]) were created, and A. germinans propagules were emplaced into these plots and monitored over time. For comparison, propagules were also placed into natural polyculture plots (1 m2). Polyculture plots contained at least two of the salt-marsh plant taxa selected for monoculture treatments, and S. virginicus was always present within these polyculture plots. Natural polyculture plots retained 59.3% +/- 11.0% (mean +/- SE) of emplaced propagules. Monocultures varied in their propagule retention capacities with plots of S. virginicus retaining on average 65.7% +/- 11.5% of transplanted propagules compared to 7.2% +/- 1.8% by B. maritima and 5.0% +/- 1.9% by S. portulacastrum. Plots containing S. virginicus retained a significantly greater percentage of emplaced propagules relative to the two succulent salt-marsh taxa. Furthermore, propagule entrapment, across all treatments, was strongly correlated with salt-marsh structure (r2 = 0.6253, P = 0.00001), which was estimated using an indirect quantitative metric (lateral obstruction) calculated from digital images of plots. Overall, our findings imply that entrapment of propagules by salt-marsh plants may be facilitative if propagules are dispersed beyond the established tree line by spring or storm tides, and that facilitation may be sustained over time. We conclude that salt-marsh ecotone permeability may modulate landward encroachment by A. germinans, and that interactions among the early life history stages of black mangroves and neighboring plants may direct community responses to climate change. PMID:22919911

Peterson, Jennifer M; Bell, Susan S

2012-07-01

216

Amylase Variation in the Salt Marsh Amphipod, GAMMARUS PALUSTRIS  

PubMed Central

There are two common alleles at the Amylase-2 locus in populations of Gammarus palustris, the salt marsh amphipod. Intensive sampling of individuals from two localities at Jamaica Bay revealed a consistent pattern of heterozygote deficiency.—Five possible sources of heterozygote deficiency were examined in this study. Four of them—selection against heterozygotes, null alleles at the locus, assortative mating for amylase genotype and inbreeding—are inconsistent with the evidence and are rejected. The fifth possibility, Wahlund effects due to genetic differentiation of the population, is tentatively accepted. Although there is no direct evidence for differentiation within this population, separate populations along the Eastern seaboard are highly differentiated in a nonclinal pattern. Furthermore, the Wahlund hypothesis is consistent with observations on differences in degree of deficiency exhibited among collections at Jamaica Bay.—Animals from this population exhibit feeding preferences correlated with genotype. Given the choice of two green algae, Enteromorpha or Ulva, the frequency of the slow allele among individuals choosing Enteromorpha was higher than among those choosing Ulva. This suggests that the animals assort themselves in the field into subpopulations with different allelic frequencies. This assortment could contribute to the maintenance of the polymorphism and to the observed heterozygote deficiency. We hypothesize that genotype influences behavior in this system through the action of enzyme on substrate, which determines the nature of the oligosaccharide pool liberated early in amylolysis.

Borowsky, Richard; Borowsky, Betty; Milani, Haleh; Greenberg, Pietra

1985-01-01

217

Populations of Methanogenic Bacteria in a Georgia Salt Marsh  

PubMed Central

Methanogens represented about 0.5% of the total bacteria in sediments from a Georgia salt marsh in which Spartina alterniflora is the predominant vegetation. The population of methanogens was composed of at least two groups of nearly equal size. One group was represented by cocci which were able to utilize trimethylamine and were unable to use H2 or acetate. The second group was composed of two subgroups which were able to utilize H2 but were unable to use trimethylamine or acetate. The more common subgroup included rod- or plate-shaped methanogens which could utilize isopropanol in addition to H2 and formate. The second subgroup included Methanococcus maripaludis, which utilized only H2 and formate. Other groups of methanogens were also present, including Methanosarcina sp. which utilized acetate, H2, and methylamines. In addition to the overall variability in the types of methanogens, the numbers of methanogens in sediments also exhibited significant spatial variability both within and between tall- and short-Spartina zones. Images

Franklin, Michael J.; Wiebe, William J.; Whitman, William B.

1988-01-01

218

Stratigraphic response of salt marshes to slow rates of sea-level change  

NASA Astrophysics Data System (ADS)

Conventional models of salt-marsh development show an idealized spatial relationship between salt-marsh floral and foraminiferal zones, where the landward margin of the marsh gradually migrates inland in response to sea-level rise. This model predicts that transgression will result in persistent and possibly expanded salt marshes at the surface, depending on a variety of factors including sediment supply, hydrologic conditions, tidal range, and rate of sea-level rise. However, in areas with abundant sediment supply and slow rates of sea- level rise, the extent of back-barrier salt marshes may decline over time as the barrier-spits mature. Sea level around the northeast coast of Newfoundland is rising at a very slow rate during the late Holocene (<0.5 mm/yr). Sandy barrier-spits and tombolos are common coastal features, but salt marshes are rare. The generalized stratigraphy of dutch cores collected in back-barrier settings in this region is a surface layer of sphagnum peat with abundant woody roots, underlain by sedge-dominated peat that transitions gradually to a thin layer of Juncus sp. peat with agglutinated foraminifera, dominantly Jadammina macrescens and Balticammina pseudomacrescens. These basal peats are interpreted as salt-marsh peats, characterized by the presence of foraminifera that are absent in overlying peat units. This sequence indicates that salt marshes developed in back-barrier environments during the initial stages of barrier progradation, then gradually transitioned to environments increasingly dominated by freshwater flora. These transitions are interpreted to reflect the progradation of the spit, decreased tidal exchange in the back-barrier, and increased influence of freshwater streams discharging into the back-barrier setting. Decreased marine influence on the back-barrier environment leads to a floral and faunal shift associated with a regressive stratigraphy in an area experiencing sea-level rise. For studies of Holocene sea-level change requiring salt-marsh stratigraphic records, it is necessary to account for changing micro-environments to locate sites appropriate for study; salt marshes may play an important role in defining the record, but may not exist at the surface to guide investigation.

Daly, J.; Bell, T.

2006-12-01

219

A comparison between conventional and AMS [sup 14]C dates on basal salt marsh peats from coastal Maine. [Accelerator Mass Spectroscopy  

Microsoft Academic Search

This study reports AMS dates from four Maine salt marshes: Webbannet Marsh (Wells), Morse and Sprague River marshes (Phippsburg), and Sanborn Cove marsh (Machiasport). The AMS dates are compared with conventional dates on bulk samples obtained from either the same cores or from other cores at comparable depths. Four AMS dates from the Webhannet and Sanborn Cove marshes were considerably

R. W. Gehrels; D. F. Belknap

1992-01-01

220

Latitudinal and climate-driven variation in the strength and nature of biological interactions in New England salt marshes  

Microsoft Academic Search

We examined the linkage between climate and interspecific plant interactions in New England salt marshes. Because harsh edaphic conditions in marshes can be ameliorated by neighboring plants, plant neighbors can have net competitive or facilitative interactions, depending on ambient physical stresses. In particular, high soil salinities, which are largely controlled by solar radiation and the evaporation of marsh porewater, can

Mark D. Bertness; Patrick J. Ewanchuk

2002-01-01

221

Man's Impact on the Environment: The Freshwater Marsh as an Ecosystem. Update.  

ERIC Educational Resources Information Center

|This environmental education program emphasizes the cause and effect of change in a freshwater marsh ecosystem with special attention given to man and his role in environmental change. Concepts are employed from the natural and social sciences to investigate environmental problems. Unit activities are inquiry oriented and answer these questions:…

Brevard County School Board, Cocoa, FL.

222

EMERGING ISSUES FOR THE RESTORATION OF TIDAL MARSH ECOSYSTEMS IN THE CONTEXT OF PREDICTED CLIMATE CHANGE  

Microsoft Academic Search

There is currently a large regional effort to restore tidal marsh ecosystems in the San Francisco Bay- Delta Estuary involving the commitment of hundreds of millions of dollars and broad landscape-scale habitat manipulations. Although climate change has been on the horizon for many years, recent developments suggest that it must be taken seriously as a factor to be considered in

John C. Callaway; V. Thomas Parker; Michael C. Vasey; Lisa M. Schile

2007-01-01

223

Uranium, thorium and lead nuclides in a Delaware salt marsh sediment  

NASA Astrophysics Data System (ADS)

Natural isotopes of uranium (234, 238), thorium (232, 230) and lead (210) have been assayed in sediments from a lower Delaware salt marsh. Uranium is concentrated in the top sections of the core and decreases with depth (3 to 1 d min-1 g-1). A significant proportion of this uranium has been authigenically extracted from seawater as demonstrated by an excess ratio of 234U:238U (1·03 1·14). Thorium (232) is rather constant (2·4 4·7 parts 10-6 for all but one sample), while the concentration of 230Th is deficient with respect to its uranium parent. In contrast to the deep sea, the fixation of authigenic reduced uranium dominates over the scavenging of 230Th in these tidal sediments. Excess 210Pb shows an exponential decay over the length of the core, and when corrected for a correspondingly significant exponential decrease in organic carbon and salt yields a sedimentation rate of 0·47 cm year-1. Although this rate approximates the local apparent rate of sea-level rise, a lower limit for the rate of salt marsh accumulation, the actual rate is higher suggesting net filling and acccretion of salt marshes. The total integrated flux of 210Pb to this and other salt marsh surfaces in the eastern U.S. is calculated to more often exceed the reported local atmospheric flux. It appears that salt marshes may scavenge 210Pb, as other trace metals, from flooding waters.

Church, Thomas M.; Lord, Charles J.; Somayajulu, B. L. K.

1981-09-01

224

Grazing rates of organic matter and living fungal biomass of decaying Spartina alterniflora by three species of salt-marsh invertebrates  

Microsoft Academic Search

The pathway for the flow of salt-marsh grass production into marsh food-webs is still not well defined. We compared the abilities\\u000a of three marsh macroinvertebrates [salt marsh periwinkles, Littoraria irrorata (Say) (=Littorina irrorata), salt-marsh coffee-bean snails, Melampus bidentatus (Say); and a talitrid amphipod, Uhlorchestia spartinophila Bounsfield and Heard] to access standing-dead leaves of smooth cordgrass (Spartina alterniflora Loisel). The invertebrates

M. A. Graça; S. Y. Newell; R. T. Kneib

2000-01-01

225

The Intertidal Burrowing Crab Neohelice (= Chasmagnathus ) granulata Positively Affects Foraging of Rodents in South Western Atlantic Salt Marshes  

Microsoft Academic Search

The role of positive and indirect interactions is often crucial in communities with intense abiotic stress such as salt marshes.\\u000a The burrowing crab, Neohelice (=Chasmagnathus) granulata, is the dominant benthic macroinvertebrate of southwest Atlantic marshes (southern Brazil to Northern Argentinean Patagonia),\\u000a having strong direct and indirect effects on marsh soil and, in consequence, on marsh vegetation and primary consumers. In

Alejandro D. Canepuccia; Maria S. Fanjul; Eugenia Fanjul; Florencia Botto; Oscar O. Iribarne

2008-01-01

226

Mechanisms of erosion along salt marsh edges: the interplay of invertebrates, vegetation, and sediment properties  

NASA Astrophysics Data System (ADS)

Many salt marshes within the shallow, coastal bays of Virginia have been experiencing rapid erosion along their bay-facing edges. Although waves are typically the driving force behind this erosion, internal properties of the marsh influence rates of erosion and the mechanisms by which erosion occurs. Sediment properties, vegetation community, and burrowing activity of crabs have been characterized at three eroding marsh sites to determine their relative importance to erosion. Two types of erosion appear to be dominant along the marsh edge at the studied sites. The first involves a form of terracing, in which the upper layer of root mat is initially removed by wave activity, which is followed by persistent erosion of the less-vegetated, underlying material. The other common mechanism by which erosion occurs is through block detachment. This is the result of large cracks or fissures that form as water travels through areas of weakness or burrow structures along the marsh edge; eventually, waves or gravity remove these large block structures from the edge. Results indicate that certain properties of the marsh edge likely impact the mechanism of erosion at work at each site. Block detachment is common at a marsh edge with abundant coverage of large communal crab burrows, sparse aboveground vegetation, and fine-grained sediment near the edge. Terracing is more prevalent at marshes with dense belowground vegetation or high mussel densities that provide stability near the surface of the marsh. Though not fully addressed in previous studies, these appear to be critical processes in regulating marsh erosion in Virginia coastal bays and are likely common along marsh edges elsewhere.

McLoughlin, S.; Wiberg, P. L.; McGlathery, K.; Fagherazzi, S.; Mariotti, G.

2010-12-01

227

Germination in relation to salinity in some plants of salt marshes in Otago, New Zealand  

Microsoft Academic Search

Germination characteristics were examined for nine halophytes occurring on Otago salt marshes and were compared with two glycophytes. The seed of most halophytes remained dormant, but viable, in saline solution for at least several months. In comparison, of the two glycophyte species, one germinated in saline solution whereas the other suffered seed mortality. There was a correlation between the salt

T. R. Partridge; J. B. Wilson

1987-01-01

228

The importance of salt-marsh wetness for seed exploitation by dabbling ducks Anas sp  

Microsoft Academic Search

The relationship between the inundation of a salt marsh in southeast Denmark not subject to lunar tides and the availability and predation of seeds of the annuals Salicornia spp. and Suada maritima by autumn staging dabbling ducks was studied by carrying out exclosure experiments over the course of 2 years. There was a marked difference in the wetness of the salt

Ole R. Therkildsen; Thomas Bregnballe

2006-01-01

229

Anthropogenic ecological change and impacts on mosquito breeding and control strategies in salt-marshes, Northern Territory, Australia.  

PubMed

Darwin, in the tropical north of Australia, is subject to high numbers of mosquitoes and several mosquito-borne diseases. Many of Darwin's residential areas were built in close proximity to tidally influenced swamps, where long-term storm-water run-off from nearby residences into these swamps has led to anthropogenic induced ecological change. When natural wet-dry cycles were disrupted, bare mud-flats and mangroves were transformed into perennial fresh to brackish-water reed swamps. Reed swamps provided year-round breeding habitat for many mosquito species, such that mosquito abundance was less predictable and seasonally dependent, but constant and often occurring in plague proportions. Drainage channels were constructed throughout the wetlands to reduce pooled water during dry-season months. This study assesses the impact of drainage interventions on vegetation and mosquito ecology in three salt-marshes in the Darwin area. Findings revealed a universal decline in dry-season mosquito abundance in each wetland system. However, some mosquito species increased in abundance during wet-season months. Due to the high expense and potentially detrimental environmental impacts of ecosystem and non-target species disturbance, large-scale modifications such as these are sparingly undertaken. However, our results indicate that some large scale environmental modification can assist the process of wetland restoration, as appears to be the case for these salt marsh systems. Drainage in all three systems has been restored to closer to their original salt-marsh ecosystems, while reducing mosquito abundances, thereby potentially lowering the risk of vector-borne disease transmission and mosquito pest biting problems. PMID:22476689

Jacups, Susan; Warchot, Allan; Whelan, Peter

2012-04-03

230

Growth of the salt marsh periwinkle Littoraria irrorata on fungal and cordgrass diets  

Microsoft Academic Search

The growth of the salt marsh periwinkleLittoraria irrorata (collected from Sapelo Island, Georgia in 1991, initial shell length 6.2 to 11.5 mm) on various diets was measured. Growth was highest on a diet of standing-dead leaves ofSpartina alterniflora. Periwinkles provided with marsh sediment, yellow-green, sterile, or bacteria-colonized leaves lost organic mass. Fungal-colonized leaves and pure mycelia of fungi common on

F. Bärlocher; S. Y. Newell

1994-01-01

231

Spatial and temporal habitat use patterns for salt marsh nekton: implications for ecological functions  

Microsoft Academic Search

We synthesized information on temporal and spatial patterns of salt marsh habitat use by nekton in order to infer the importance\\u000a of five main types of marsh function: reproduction, foraging, refuge from predation, refuge from stressful environmental conditions\\u000a and environmental enhancement of physiology. We then extended the concept that intertidal gradients regulate habitat use patterns\\u000a of nekton to a more

Rodney A. Rountree; Kenneth W. Able

2007-01-01

232

Growth and production of the mummichog ( Fundulus heteroclitus ) in a restored salt marsh  

Microsoft Academic Search

The mummichog,Fundulus heteroclitus, is one of the most important macrofaunal components of salt marsh surfaces and an important link to subtidal areas of the\\u000a adjacent estuary along the east coast of the U.S. We estimated growth, population size, and production of the mummichog in\\u000a a restored marsh in order to improve our understanding of the role of this resident fish

S. L. H. Teo; K. W. Able

2003-01-01

233

Crab: snail size-structured interactions and salt marsh predation gradients  

Microsoft Academic Search

We studied size-structured predator-prey interactions between blue crabs (Callinectes sapidus) and marsh periwinkles (Littoraria irrorata) with a combination of field studies, laboratory experiments and individual-based modeling. Size distributions of Littoraria differed among years at the same sites in a salt marsh and could largely be explained by dominance of strong cohorts in the population. At a given site, abundance increased

Daniel E. Schindler; Brett M. Johnson; Neil A. MacKay; Nicolaas Bouwes; James F. Kitchell

1994-01-01

234

Salt Marsh-Upland Ecotones in Central California: Vulnerability to Invasions and Anthropogenic Stressors  

Microsoft Academic Search

Ecotones, zones of abrupt biological transition typically reflecting strong physical gradients, may be particularly sensitive\\u000a to changes in environmental conditions. Our characterization of the ecotone between salt marshes and uplands in the Elkhorn\\u000a Slough watershed in central California revealed that extent of appropriate habitat for native high marsh species endemic to\\u000a this zone is extremely limited. The ecotone is highly

Kerstin Wasson; Andrea Woolfolk

2011-01-01

235

Relationships of salt-marsh plant distributions to tidal levels in Connecticut, USA  

Microsoft Academic Search

A three-year study of Connecticut, USA, salt-marsh vegetation was undertaken to determine the relationship of its distribution on the marsh surface to tidal levels, particularly mean high water (MHW) as measured on each of three sites representing different tidal amplitudes. Elevations and species present were measured on 1-m2 grids in 10x 70-m belt transects at each site. After the data

Michael Wm. Lefor; William C. Kennard; Daniel L. Civco

1987-01-01

236

Seasonal cycling of sulfur and iron in porewaters of a Delaware salt marsh  

Microsoft Academic Search

Luther G.W. III. and Church. T.M.• 1988. Seasonal cycling of sulfur and iron in porewaters of a Delaware salt marsh. Mar. Chem.• 23: 295-309. An extensive porewater data set has been gathered in the Great Marsh. Delaware over various seasons. salinities and tides. The data all point to a complimentary redox cycle for sulfur and iron which operates seasonally and

G LUTHERIII; THOMAS M. CHURCH

1988-01-01

237

Trophic Cascades Uncoupled in a Coastal Marsh Ecosystem  

Microsoft Academic Search

The Mediterranean population of the exotic eastern mosquitofish Gambusia holbrooki (Agassiz 1859) (Osteichthyes, Poeciliidae) has been held responsible for causing eutrophication due to zooplankton removal\\u000a and phytoplankton enhancement, however no experimental evidence exists of this. To test this allegation, an enclosure experiment\\u000a was conducted in spring in an oligohaline coastal marsh. The manipulation of fish density had profound effects on

Luis Cardona

2006-01-01

238

A survey of zinc, copper and cadmium concentrations in salt marsh plants along the Dutch coast.  

PubMed

In autumn 1986, plants and soil were collected from the lower and the higher salt marsh zones of salt marshes along the Dutch coast. The main purpose was to get an overview of Zn, Cu and Cd concentrations in six dominant species of salt marsh plants. The roots and shoots of the plants were analysed for Zn, Cu and Cd. The highest heavy metal concentrations were found in plants collected from salt marshes near harbour areas and/or that are known to receive contaminated fluvial sediment. Dicotyledonous plant species tended to have similar heavy metal concentrations in roots and shoots, whereas in monocotyledonous species the concentrations in the roots were two to three times higher than in the shoots. Differences in accumulation in the roots between elements and between plant species were found. Cd was accumulated more than Zn or Cu. Triglochin maritima shows a low Cd uptake by roots, whereas Spartina anglica and Scirpus maritimus tend to accumulate it. The fraction of soil particles smaller than 63 microm, loss on ignition and Zn, Cu and Cd concentrations were determined in soil samples. The highest Zn, Cu and Cd concentrations in the soil were found at salt marshes in the Western Scheldt area and were nine, five and 20 times higher than background levels, respectively. PMID:15092100

Otte, M L; Bestebroer, S J; van der Linden, J M; Rozema, J; Broekman, R A

1991-01-01

239

Multi-seasonal spectral characteristics analysis of coastal salt marsh vegetation in Shanghai, China  

NASA Astrophysics Data System (ADS)

Remote sensing technology has become the primary tool for ecological research on a large scale. The spectral characteristics of the salt marsh vegetation canopy, including four main communities, Phragmites australis community, Spartina alterniflora community, Scirpus mariqueter community and Carex scabrifolia community, were measured in the seasons of spring, summer and autumn by a ground FieldSpec™ Pro JR spectroradiometer, at the Chongming Dongtan Nature Reserve in Shanghai. The spectral data were converted to the reflectance curves, and their first derivative curves between 350 nm and 1000 nm were calculated. The differences in the reflectance and first derivative curves were then analyzed, with particular attention paid to the characteristics in the bands of visible, "green peak", "red edge" and near infrared. The results from this study showed that the different salt marsh communities had different and rather unique spectral characteristics during the three seasons studied. The near-ground spectral reflectance varied with the growing season, community type and its phenology. The discrimination ability, in terms of variations in the spectral reflectance, among the four major salt marsh communities was highest in autumn. It is proposed that a realistic strategy for classifying the salt marsh vegetation could be adopted by integrating and analyzing their remotely sensed images of multi-seasons. The implications of the results from this study in terms of serving as a tool for monitoring and mapping the distribution pattern and dynamics of salt marsh vegetation on the eastern coast of China are discussed.

Gao, Z. G.; Zhang, L. Q.

2006-08-01

240

Quantifying Microbial Utilization of Petroleum Hydrocarbons in Salt Marsh Sediments by Using the 13C Content of Bacterial rRNA  

Microsoft Academic Search

Natural remediation of oil spills is catalyzed by complex microbial consortia. Here we took a whole- community approach to investigate bacterial incorporation of petroleum hydrocarbons from a simulated oil spill. We utilized the natural difference in carbon isotopic abundance between a salt marsh ecosystem supported by the 13C-enriched C4 grass Spartina alterniflora and 13 C-depleted petroleum to monitor changes in

Ann Pearson; Kimberly S. Kraunz; Alex L. Sessions; Anne E. Dekas; William D. Leavitt; Katrina J. Edwards

2008-01-01

241

Inter-annual Variability in Net Ecosystem Exchange of Carbon Dioxide and Methane Emissions in a Temperate Freshwater Marsh  

Microsoft Academic Search

There exists very little information on greenhouse gas (GHG) exchange in marsh wetlands, especially in temperate climates. Measurements of carbon dioxide (CO2) and methane (CH4) fluxes were made from May 2005 to June 2008 in a temperate freshwater cattail marsh in Eastern Ontario, Canada. The net ecosystem exchange (NEE) of CO2 was measured continuously using the eddy covariance technique, and

M. Bonneville; I. Strachan

2009-01-01

242

Habitat influences on reproductive allocation and growth of the mummichog ( Fundulus heteroclitus ) in a coastal salt marsh  

Microsoft Academic Search

To determine whether life history differences can occur in salt marsh fishes that occupy different habitats within the same\\u000a marsh, we compared reproductive allocation in female mummichog (Fundulus heteroclitus) inhabiting creeks and ponds of a coastal salt marsh in southern New Jersey, USA during the spring and summer of 2001 and\\u000a 2002. Females were collected in phase with the lunar

Karen L. Hunter; Michael G. Fox; Kenneth W. Able

2007-01-01

243

Spatial and temporal distribution patterns of the macrozoobenthos assemblage in the salt marshes of Tejo estuary (Portugal)  

Microsoft Academic Search

The present study focuses on the spatial and temporal distribution of the macroinvertebrate community of the salt marsh areas\\u000a of the Tejo estuary, based on surveys conducted from autumn 1998 to summer 2000. Samples were collected quarterly in five\\u000a different intertidal areas along an elevation gradient in: mudflats, creek mouths, creeks, pioneer salt marsh areas and middle\\u000a marsh areas. A

João P. Salgado; H. N. Cabral; M. J. Costa

2007-01-01

244

Soils-Based Rapid Assessment for Quantifying Changes in Salt Marsh Condition as a Result of Hydrologic Alteration  

Microsoft Academic Search

Wetland condition can be severely altered as a result of a change in hydrology. In this study, we examined several soil-based\\u000a methods to quantify and assess changes in salt marsh condition as a result of tidal restriction. Soil properties were compared\\u000a between two tidally restricted and two (paired) unrestricted salt marshes. Organic horizon morphology provided a qualitative\\u000a metric of marsh

Timothy M. Twohig; Mark H. Stolt

245

Size and species diversity of zooplankton communities in fluctuating Mediterranean salt marshes  

NASA Astrophysics Data System (ADS)

Differences in size and species diversity were analysed in a zooplankton community of a Mediterranean salt marsh (Empordà wetlands, NE Iberian Peninsula), where the dominance of a single species was frequent. In the permanent salt marsh, species diversity and size diversity had similar patterns along zooplankton succession. In the temporary salt marsh species diversity was high after flooding and diminished once water inputs ceased. As species diversity declined size diversity increased. Eventually, one species of calanoid dominated the zooplankton community. The high size diversity in situations of calanoid dominance was possibly due to the co-occurrence of different developmental stages, each of which have different diets. Size diversity would thus indicate trophic niche segregation among different sizes. The combined use of species and size diversity values allows the identification of the successional phases.

Brucet, S.; Boix, D.; Lopez-Flores, R.; Badosa, A.; Quintana, X. D.

2006-04-01

246

Acute salt marsh dieback in the Mississippi River deltaic plain: A drought-induced phenomenon?  

USGS Publications Warehouse

Aims Extensive dieback of salt marsh dominated by the perennial grass Spartina alterniflora occurred throughout the Mississippi River deltaic plain during 2000. More than 100,000 ha were affected, with 43,000 ha severely damaged. The aim of this work was to determine if sudden dieback could have been caused by a coincident drought and to assess the significance of this event with respect to long-term changes in coastal vegetation. Location Multiple dieback sites and reference sites were established along 150 km of shoreline in coastal Louisiana, USA. Methods Aerial and ground surveys were conducted from June 2000 to September 2001 to assess soil conditions and plant mortality and recovery. Results Dieback areas ranged in size from???300 m2-5 km2 in area with 50-100% mortality of plant shoots and rhizomes in affected zones. Co-occurring species such as Avicennia germinans (black mangrove) and Juncus roemerianus (needlegrass rush) were unaffected. Historical records indicate that precipitation, river discharge, and mean sea level were unusually low during the previous year. Although the cause of dieback is currently unknown, plant and soil characteristics were consistent with temporary soil desiccation that may have reduced water availability, increased soil salinity, and/or caused soil acidification (via pyrite oxidation) and increased uptake of toxic metals such as Fe or Al. Plant recovery 15 months after dieback was variable (0-58% live cover), but recovering plants were vigorous and indicated no longlasting effects of the dieback agent. Main conclusions These findings have relevance for global change models of coastal ecosystems that predict vegetation responses based primarily on long-term increases in sea level and submergence of marshes. Our results suggest that large-scale changes in coastal vegetation may occur over a relatively short time span through climatic extremes acting in concert with sea-level fluctuations and pre-existing soil conditions. ?? 2004 Blackwell Publishing Ltd.

McKee, K. L.; Mendelssohn, I. A.; Materne, M. D.

2004-01-01

247

Phylogenetic Analysis of Culturable Dimethyl Sulfide-Producing Bacteria from a Spartina-Dominated Salt Marsh and Estuarine Water  

Microsoft Academic Search

Dimethylsulfoniopropionate (DMSP), an abundant osmoprotectant found in marine algae and salt marsh cordgrass, can be metabolized to dimethyl sulfide (DMS) and acrylate by microbes having the enzyme DMSP lyase. A suite of DMS-producing bacteria isolated from a salt marsh and adjacent estuarine water on DMSP agar plates differed markedly from the pelagic strains currently in culture. While many of the

JOHN H. ANSEDE; ROBERT FRIEDMAN; DUANE C. YOCH

2001-01-01

248

Quantitative vertical zonation of salt-marsh foraminifera for reconstructing former sea level; an example from New Jersey, USA  

Microsoft Academic Search

We present a quantitative technique to reconstruct sea level from assemblages of salt-marsh foraminifera using partitioning around medoids (PAM) and linear discriminant functions (LDF). The modern distribution of foraminifera was described from 62 surface samples at three salt marshes in southern New Jersey. PAM objectively estimated the number and composition of assemblages present at each site and showed that foraminifera

Andrew C. Kemp; Benjamin P. Horton; David R. Vann; Simon E. Engelhart; Candace A. Grand Pre; Christopher H. Vane; Daria Nikitina; Shimon C. Anisfeld

249

Practical proxies for tidal marsh ecosystem services: application to injury and restoration.  

PubMed

Tidal marshes are valued, protected and restored in recognition of their ecosystem services: (1) high productivity and habitat provision supporting the food web leading to fish and wildlife, (2) buffer against storm wave damage, (3) shoreline stabilization, (4) flood water storage, (5) water quality maintenance, (6) biodiversity preservation, (7) carbon storage and (8) socio-economic benefits. Under US law, federal and state governments have joint responsibility for facilitating restoration to compensate quantitatively for ecosystem services lost because of oil spills and other contaminant releases on tidal marshes. This responsibility is now met by choosing and employing metrics (proxies) for the suite of ecosystem services to quantify injury and scale restoration accordingly. Most injury assessments in tidal marshes are triggered by oil spills and are limited to: (1) documenting areas covered by heavy, moderate and light oiling; (2) estimating immediate above-ground production loss (based on stem density and height) of the dominant vascular plants within each oiling intensity category and (3) sampling sediments for chemical analyses and depth of contamination, followed by sediment toxicity assays if sediment contamination is high and likely to persist. The percentage of immediate loss of ecosystem services is then estimated along with the recovery trajectory. Here, we review potential metrics that might refine or replace present metrics for marsh injury assessment. Stratifying plant sampling by the more productive marsh edge versus the less accessible interior would improve resolution of injury and provide greater confidence that restoration is truly compensatory. Using microphytobenthos abundance, cotton-strip decomposition bioassays and other biogeochemical indicators, or sum of production across consumer trophic levels fails as a stand-alone substitute metric. Below-ground plant biomass holds promise as a potential proxy for resiliency but requires further testing. Under some conditions, like chronic contamination by organic pollutants that affect animals but not vascular plants, benthic infaunal density, toxicity testing, and tissue contamination, growth, reproduction and mortality of marsh vertebrates deserve inclusion in the assessment protocol. Additional metrics are sometimes justified to assay microphytobenthos, use by nekton, food and habitat for reptiles, birds and mammals, or support of plant diversity. Empirical research on recovery trajectories in previously injured marshes could reduce the largest source of uncertainty in quantifying cumulative service losses. PMID:18929066

Peterson, Charles H; Able, Kenneth W; Dejong, Christin Frieswyk; Piehler, Michael F; Simenstad, Charles A; Zedler, Joy B

2008-01-01

250

Critical bifurcation of shallow microtidal landforms in tidal flats and salt marshes.  

PubMed

Shallow tidal basins are characterized by extensive tidal flats and salt marshes that lie within specific ranges of elevation, whereas intermediate elevations are less frequent in intertidal landscapes. Here we show that this bimodal distribution of elevations stems from the characteristics of wave-induced sediment resuspension and, in particular, from the reduction of maximum wave height caused by dissipative processes in shallow waters. The conceptual model presented herein is applied to the Venice Lagoon, Italy, and demonstrates that areas at intermediate elevations are inherently unstable and tend to become either tidal flats or salt marshes. PMID:16707583

Fagherazzi, Sergio; Carniello, Luca; D'Alpaos, Luigi; Defina, Andrea

2006-05-17

251

Critical bifurcation of shallow microtidal landforms in tidal flats and salt marshes  

PubMed Central

Shallow tidal basins are characterized by extensive tidal flats and salt marshes that lie within specific ranges of elevation, whereas intermediate elevations are less frequent in intertidal landscapes. Here we show that this bimodal distribution of elevations stems from the characteristics of wave-induced sediment resuspension and, in particular, from the reduction of maximum wave height caused by dissipative processes in shallow waters. The conceptual model presented herein is applied to the Venice Lagoon, Italy, and demonstrates that areas at intermediate elevations are inherently unstable and tend to become either tidal flats or salt marshes.

Fagherazzi, Sergio; Carniello, Luca; D'Alpaos, Luigi; Defina, Andrea

2006-01-01

252

Tagus estuary and Ria de Aveiro salt marsh dynamics and the impact of sea level rise  

NASA Astrophysics Data System (ADS)

Different characteristics of Spartina maritima found in two distinct salt marshes located in different estuaries were analysed through interpretation of their local hydrodynamic patterns, as well as the impact of sea level rise on physical processes and consequently on plant dynamics and salt marshes stability. These salt marshes are situated in two of the most important Portuguese coastal systems, Tagus estuary (Rosário salt marsh) and Ria de Aveiro lagoon (Barra salt marsh), which are dominated by physical processes that induce strong tidal currents. They were monitored during one year and plant and sediment samples of S. maritima were collected quarterly in order to determine the vegetation coverage, above and belowground biomass, organic matter and sediment moisture. Residual circulation, tidal asymmetry and tidal dissipation were determined from numerical modelling results of the MOHID 2D model that was applied to each coastal system, considering the actual sea level and a sea level rise (SLR) scenario.

Valentim, J. M.; Vaz, N.; Silva, H.; Duarte, B.; Caçador, I.; Dias, J. M.

2013-09-01

253

Temporal changes and spatial variation of soil oxygen consumption, nitrification and denitrification rates in a tidal salt marsh of the Lagoon of Venice, Italy  

Microsoft Academic Search

The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh

P. G. Eriksson; J. M. Svensson; G. M. Carrer

2003-01-01

254

Long-Term Sediment Dynamics in a Tidal Salt Marsh, North Inlet, South Carolina  

NASA Astrophysics Data System (ADS)

The salt marshes along the southeastern U.S. coast are in a delicate balance between rates of sediment accretion and relative sea level rise. Short-term sediment flux studies in the region indicate a net export of suspended sediment out of salt marsh systems despite the necessity for these marshes to import sediment in order to keep pace with relative sea level rise. Long-term suspended sediment concentration data collected daily through the Long-Term Ecological Research Program (LTER) are utilized in this study. The objective of this study is to identify the relative importance of different processes including tidal range, rainfall, winds, water temperature and river discharge in effecting suspended sediment concentrations in salt marsh channels. The study area is a small {\\Spartina}- and {\\Juncus}-dominated salt marsh located at North Inlet, South Carolina. Suspended sediment concentrations were collected daily at 3 sites in the marsh basin at approximately 1000 hrs EST for a period of 10 to 15 years. The determination of how suspended sediment concentrations vary with respect to the tidal cycle required identification of the phase within the cycle that the sample was collected. This was achieved predicting tidal phases using sea surface elevation data. Suspended sediment concentrations collected during periods of different rainfall, tidal ranges, wind conditions, water temperatures and freshwater discharge were used to develop "representative" tidal cycles for each of the aforementioned forcings. Mean suspended sediment concentrations were found to be highest during the ebb tide while the lowest concentrations were found following high and low slack water. These concentrations vary spatially throughout the marsh with the highest concentrations located at the most landward site and lowest at the site nearest the inlet. A seasonal bias of suspended sediment concentrations was observed with highest concentrations in the summer months. Import of sediment in the system coincides with spring tides while export occurs during neap tidal conditions. Rainfall increases sediment concentration in the channels and appears to be associated with periods of sediment redistribution within the marsh. The impact of river discharge on suspended sediment concentrations affects the marsh over longer time intervals with years of low discharge into adjacent Winyah Bay coinciding with periods of low suspended sediment concentrations. Water discharge through each channel will be estimated using harmonic analysis of tidal current records collected over a 30-day period in order to resolve spring-neap variations in tidal velocity. The coupling of mean suspended sediment concentration and water discharge of the same phase will later be used to produce a long-term sediment budget for the marsh basin.

Murphy, S.; Voulgaris, G.

2001-05-01

255

Exchanges and photo-biogeochemical transformation of dissolved organic compounds in Eastern US tidal marsh ecosystems.  

NASA Astrophysics Data System (ADS)

The role of tidal marshes as sources, sinks and/or transformers of biologically important nutrients, carbon and pollutants has been studied in various marsh-estuarine environments and geomorphological settings. Although there is no consensus on the magnitude and direction of marsh-estuary net (particulate and dissolved) organic fluxes, most previous studies suggest that salt marshes export dissolved organic carbon (DOC) to the surrounding estuarine waters. There has been less attention, however, to the influence of transformations on marsh-exported organic carbon composition or "quality". Yet, carbon composition affects a wide variety of estuarine processes, including microbial respiration and photochemistry. Our objectives in this study were to quantify the photo-reactivity and bio-availability of dissolved organic carbon compounds exported from tidal wetlands of the Chesapeake Bay and determine their effects on the optical properties of colored organic matter (CDOM). We quantified DOC bioavailability with two assays of microbial mineralization: the traditional batch incubation approach in which a suspension of DOM and microbial cells (1 µm filtrate) was incubated in bottles for 7 d, and a continuous-flow bioreactor approach in which DOC (0.2 µm filtrate) was passed through a microbial community that had been pre-established on glass beads from the same source water. Photochemical degradation was measured after a 10h exposure to filtered xenon irradiance simulating midday surface exposure. We measured decreases in CDOM absorption and fluorescence spectra, DOC concentrations, changes in molecular weight distribution, and increases in dissolved inorganic carbon (DIC) and CO2. Results provide important insights on the transformation, fate and cycling of marsh-exported organic compounds, and the role of tidal marsh systems as major regulators of short-scale biological, optical and biogeochemical variability in highly dynamic coastal margins and catchment areas.

Tzortziou, Maria; Neale, Patrick; Megonigal, Patrick; Butterworth, Megan; Jaffe, Rudolf

2010-05-01

256

The role of Phragmites australis in mediating inland salt marsh migration in a Mid-Atlantic Estuary.  

PubMed

Many sea level rise adaptation plans emphasize the protection of adjacent uplands to allow for inland salt marsh migration, but little empirical information exists on this process. Using aerial photos from 1930 and 2006 of Delaware Estuary coastal habitats in New Jersey, I documented the rate of coastal forest retreat and the rate of inland salt marsh migration across 101.1 km of undeveloped salt marsh and forest ecotone. Over this time, the amount of forest edge at this ecotone nearly doubled. In addition, the average amount of forest retreat was 141.2 m while the amount of salt marsh inland migration was 41.9 m. Variation in forest retreat within the study area was influenced by variation in slope. The lag between the amount of forest retreat and salt marsh migration is accounted for by the presence of Phragmites australis which occupies the forest and salt marsh ecotone. Phragmites expands from this edge into forest dieback areas, and the ability of salt marsh to move inland and displace Phragmites is likely influenced by salinity at both an estuary-wide scale and at the scale of local subwatersheds. Inland movement of salt marsh is lowest at lower salinity areas further away from the mouth of the estuary and closer to local heads of tide. These results allow for better prediction of salt marsh migration in estuarine landscapes and provide guidance for adaptation planners seeking to prioritize those places with the highest likelihood of inland salt marsh migration in the near-term. PMID:23705031

Smith, Joseph A M

2013-05-21

257

Channel and Flow Relationships in Tidal Salt Marsh Wetlands.  

National Technical Information Service (NTIS)

In a natural tidal channel in Tule Slough, Petaluma Marsh bordering the Petaluma River north of San Pablo Bay, synoptic measurements of stage and velocity were made at 7 locations along the 3 mile length of the channel. The purpose was to measure gage hei...

L. B. Leopold L. Collins M. Inbar

1984-01-01

258

Temporal changes and spatial variation of soil oxygen consumption, nitrification and denitrification rates in a tidal salt marsh of the Lagoon of Venice, Italy  

NASA Astrophysics Data System (ADS)

The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh creeks and in areas covered by the dominant vegetation, Limonium serotinum. In May, cores were also collected in areas with vegetation dominated by Juncus maritimus and Halimione portulacoides. In laboratory incubations at in situ temperature in the dark, flux rates of oxygen and DIN were monitored in the overlying water of the intact cores. 15N-nitrate was added to the overlying water and nitrification and denitrification were measured using isotope-dilution and -pairing techniques. The results show that highest soil oxygen consumption coincided with the highest water temperature in June and July. The highest denitrification rates were recorded in spring and autumn coinciding with the highest nitrate concentrations. Soil oxygen consumption and nitrification rates differed between sampling sites, but denitrification rates were similar among the different vegetation types. The highest rates were recorded in areas covered with L. serotinum. Burrowing soil macrofauna enhanced oxygen consumption, nitrification and denitrification in April and May. The data presented in this study indicate high temporal as well as spatial variations in the flux of oxygen and DIN, and nitrogen transformations in the tidal salt marshes of the Venice lagoon during the growth season. The results identify the salt marshes of the Venice lagoon as being metabolically very active ecosystems with a high capacity to process nitrogen.

Eriksson, P. G.; Svensson, J. M.; Carrer, G. M.

2003-12-01

259

Dissolved Inorganic Nitrogen Pools and Surface Flux under Different Brackish Marsh Vegetation Types, Common Reed ( Phragmites australis ) and Salt Hay ( Spartina patens )  

Microsoft Academic Search

The current expansion of Phragmites australis into the high marsh shortgrass (Spartina patens, Distichlis spicata) communities of eastern U.S. salt marshes provided an opportunity to identify the influence of vegetation types on pools and fluxes of dissolved inorganic nitrogen (DIN). Two brackish tidal marshes of the National Estuarine Research Reserve system were examined, Piermont Marsh of the Hudson River NERR

Lisamarie Windham-Myers

2005-01-01

260

Feedbacks underlie the resilience of salt marshes and rapid reversal of consumer-driven die-off.  

PubMed

Understanding ecosystem resilience to human impacts is critical for conservation and restoration. The large-scale die-off of New England salt marshes was triggered by overfishing and resulted from decades of runaway crab grazing. In 2009, however, cordgrass began to recover, decreasing die-off -40% by 2010. We used surveys and experiments to test whether plant-substrate feedbacks underlie marsh resilience. Initially, grazer-generated die-off swept through the cordgrass, creating exposed, stressful peat banks that inhibited plant growth. This desertification cycle broke when banks eroded and peat transitioned into mud with fewer herbivores, less grazing, and lower physical stress. Cordgrass reestablished in these areas through a feedback where it engineered a recovery zone by further ameliorating physical stresses and facilitating additional revegetation. Our results reveal that feedbacks can play a critical role in rapid, reversible ecosystem shifts associated with human impacts, and that the interplay of facilitative and consumer interactions should be incorporated into resilience theory. PMID:23951724

Altieri, Andrew H; Bertness, Mark D; Coverdale, Tyler C; Axelman, Eric E; Herrmann, Nicholas C; Szathmary, P Lauren

2013-07-01

261

MARSH INSITU EH DATA FOR SOUTH FLORIDA ECOSYSTEM ASSESSMENT PROJECT  

EPA Science Inventory

The South Florida Ecosystem Assessment Project is an innovative, large-scale monitoring and assessment program designed to measure current and changing conditions of ecological resources in South Florida using an integrated holistic approach. This data set contains results for f...

262

Macroinfauna of a Southern New England salt marsh: seasonal dynamics and production  

Microsoft Academic Search

The animal-habitat relationships and seasonal dynamics of the benthic macroinfauna were investigated from November 1986 to October 1988 in the Great Sippe-wissett salt marsh (Massachusetts, USA). Total macrofaunal abundance varied seasonally, displaying a peak in late spring and early summer, then declining sharply during late summer and recovering briefly in fall before collapsing in winter. Three macroinfaunal assemblages were found

R. Sardá; K. Foreman; I. Valiela

1995-01-01

263

Variation in insect herbivory across a salt marsh tidal gradient influences plant survival and distribution  

Microsoft Academic Search

Herbivore damage and impact on plants often varies spatially across environmental gradients. Although such variation has been hypothesized to influence plant distribution, few quantitative evaluations exist. In this study I evaluated patterns of insect herbivory on an annual forb, Atriplex patula var. hastata, across a salt marsh tidal gradient, and performed experiments to examine potential causes and consequences of variation

Tatyana A. Rand

2002-01-01

264

Uranium, thorium and lead nuclides in a Delaware salt marsh sediment  

Microsoft Academic Search

Natural isotopes of uranium (234, 238), thorium (232, 230) and lead (210) have been assayed in sediments from a lower Delaware salt marsh. Uranium is concentrated in the top sections of the core and decreases with depth (3 to 1 d min-1 g-1). A significant proportion of this uranium has been authigenically extracted from seawater as demonstrated by an excess

Thomas M. Church; Charles J. Lord; B. L. K. Somayajulu

1981-01-01

265

Salt marsh sediment bacteria: their distribution and response to external nutrient inputs  

Microsoft Academic Search

A primary focus among microbial ecologists in recent years has been to understand controls on the distribution of microorganisms in various habitats. Much less attention has been paid to the way that environmental disturbance interacts with processes that regulate bacterial community composition. We determined how human disturbance affected the distribution and community structure of salt marsh sediment bacteria by using

Jennifer L Bowen; Byron C Crump; Linda A Deegan; John E Hobbie

2009-01-01

266

Biogeochemical cycling of methylmercury at Barn Island Salt Marsh, Stonington, CT, USA  

Microsoft Academic Search

Monomethylmercury (MMHg) is toxic, and is the primary form of Hg thatbioaccumulates in the food web. An understanding of its distribution,production, and transport is needed. Prior investigations indicate thatmethylation is mediated by sulfate-reducing bacteria, yet limited in highsulfate environments. High rates of microbial respiration and strong oxygengradients are found in salt marshes. It is hypothesized that significant in situ methylation

C. S. Langer; W. F. Fitzgerald; P. T. Visscher; G. M. Vandal

2001-01-01

267

Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes  

Microsoft Academic Search

The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three salt- marsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable

J. L. Espinar; L. V. Garcia; L. Clemente

2005-01-01

268

Oxygen Dynamics in Crude Oil Contaminated Salt Marshes: I. Aerobic Respiration Model  

Microsoft Academic Search

A simple model was developed to predict oxygen demand exerted by aerobic biodegradation of spilled crude oil and fertilizer added to stimulate biodegradation in salt marsh sediment. The role of aerobic respiration (AR) was determined using first-order G kinetics. The G kinetic rate constants were calculated from laboratory data sets through linear regression. The effect of oil and fertilizer on

W. S. Shin; J. H. Pardue

2001-01-01

269

Magnetic properties of salt-marsh soils contaminated by iron industry emissions (southeast France)  

Microsoft Academic Search

Detailed magnetic properties of salt-marsh soils exposed to intense atmospheric deposition of fly ashes from the iron industry (southeast France) are reported. An enhancement in the concentration of magnetic particles in topsoil through this area is observed. Low values of frequency-dependent susceptibility (?FD) are characteristic of coarse multidomain (MD) grains and were observed in surface samples. Concentration of ferrimagnetic minerals

Hélène Lecoanet; François Lévêque; Jean-Paul Ambrosi

2001-01-01

270

HEMIPARASITES GENERATE ENVIRONMENTAL HETEROGENEITY AND ENHANCE SPECIES COEXISTENCE IN SALT MARSHES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tidal inundation and salinity are considered to be controlling factors in salt marsh species distributions. Parasitic plants may also influence community organization as parasite – host interactions may play a functional role in stress amelioration due to physiological mechanisms for salinity toler...

271

Vegetation loss alters soil nitrogen dynamics in an Arctic salt marsh  

Microsoft Academic Search

Summary 1 Plant and microbial nitrogen (N) dynamics were examined in soils of an Arctic salt marsh beneath goose-grazed swards and in degraded soils. The degraded soils are the outcome of intensive destructive foraging by geese, which results in vegetation loss and near-irreversible changes in soil properties. The objective of the study was to determine whether vegetation loss led to

KATE M. BUCKERIDGE; ROBERT L. JEFFERIES

2007-01-01

272

Monitoring anthropogenic radioactivity in salt marsh environments through in situ gamma-ray spectrometry  

Microsoft Academic Search

Radionuclide bearing effluents discharged into the Irish Sea have resulted in the accumulation of radionuclides in salt marsh environments which can contribute to critical group exposures. Recent developments in in situ gamma-ray spectrometry provide a novel and effective method for monitoring anthropogenic radionuclide concentrations and distributions within these coastal environments. This paper presents the results from an in situ survey

Andrew N. Tyler

1999-01-01

273

Decomposition processes of Spartina maritima in a salt marsh of the Basque Country  

Microsoft Academic Search

Decomposition dynamics of aerial parts and root-rhizomes of Spartina maritima in a Basque Country salt marsh was studied, using litter bags placed on the soil surface and buried 10 cm below ground. Aerial parts of the plant in aboveground position showed higher breakdown rates than samples placed belowground. There was no significant difference found between aerial parts and root-rhizomes buried.

J. Pozo; R. Colino

1992-01-01

274

Estimating shallow subsidence in microtidal salt marshes of the southeastern United States: Kaye and Barghoorn revisited  

Microsoft Academic Search

Simultaneous measurements of vertical accretion and change in surface elevation relative to a shallow (3–5 m) subsurface datum were made in selected coastal salt marshes of Louisiana, Florida, and North Carolina to quantitatively test Kaye and Barghoorn's contention that vertical accretion is not a good surrogate for surface elevation change because of autocompaction of the substrate. Rates of subsidence of

Donald R. Cahoon; Denise J. Reed; John W. Day

1995-01-01

275

Modelling the effects of sediment compaction on salt marsh reconstructions of recent sea-level rise  

NASA Astrophysics Data System (ADS)

This paper quantifies the potential influence of sediment compaction on the magnitude of nineteenth and twentieth century sea-level rise, as reconstructed from salt marsh sediments. We firstly develop a database of the physical and compression properties of low energy intertidal and salt marsh sediments. Key compression parameters are controlled by organic content (loss on ignition), though compressibility is modulated by local-scale processes, notably the potential for desiccation of sediments. Using this database and standard geotechnical theory, we use a numerical modelling approach to generate and subsequently ‘decompact’ a range of idealised intertidal stratigraphies. We find that compression can significantly contribute to reconstructed accelerations in recent sea level, notably in transgressive stratigraphies. The magnitude of this effect can be sufficient to add between 0.1 and 0.4 mm yr-1 of local sea-level rise, depending on the thickness of the stratigraphic column. In contrast, records from shallow (<0.5 m) uniform-lithology stratigraphies, or shallow near-surface salt marsh deposits in regressive successions, experience negligible compaction. Spatial variations in compression could be interpreted as ‘sea-level fingerprints’ that might, in turn, be wrongly attributed to oceanic or cryospheric processes. However, consideration of existing sea-level records suggests that this is not the case and that compaction cannot be invoked as the sole cause of recent accelerations in sea level inferred from salt marsh sediments.

Brain, Matthew J.; Long, Antony J.; Woodroffe, Sarah A.; Petley, David N.; Milledge, David G.; Parnell, Andrew C.

2012-09-01

276

Critical Bifurcation of Shallow Microtidal Landforms in Tidal Flats and Salt Marshes  

Microsoft Academic Search

Shallow tidal basins are characterized by extensive tidal flats and salt marshes that lie within specific ranges of elevation, whereas intermediate elevations are less frequent in intertidal landscapes. Here we show that this bimodal distribution of elevations stems from the characteristics of wave induced sediment resuspension, and, in particular, from the reduction of maximum wave height caused by dissipative processes

Sergio Fagherazzi; Luca Carniello; Luigi D'Alpaos; Andrea Defina

2006-01-01

277

Salt Marsh 'Culicoides' (Diptera: Ceratopogonidae): Species, Seasonal Abundance and Comparisons of Trapping Methods.  

National Technical Information Service (NTIS)

The spatial and seasonal abundance of adult Culicoides in a coastal Spartina salt marsh in North Carolina was determined during a 2-year period by a light trap, emergence traps, and sticky cylinder traps. Twelve species were collected, the greatest number...

D. L. Kline R. C. Axtell

1976-01-01

278

Mycorrhizal fungi determine salt-marsh plant zonation depending on nutrient supply  

Microsoft Academic Search

Summary 1. Arbuscular mycorrhizal fungi (AMF) can affect nutrient uptake of associated plants and can vary in function from mutualism to parasitism as nutrient availability increases; thus they may interact with nutrient availability to influence plant community structure. 2. We experimentally investigated the hypotheses that AMF can affect the community structure of salt marshes by affecting plant competitive ability. We

Pedro Daleo; Juan Alberti; Alejandro Canepuccia; Mauricio Escapa; Eugenia Fanjul; Brian R. Silliman; Mark D. Bertness; Oscar Iribarne

2008-01-01

279

Release into the environment of metals by two vascular salt marsh plants  

Microsoft Academic Search

Metals in contaminated salt marshes are mainly locked in the anaerobic layer of sediments, where they are tightly bound as sulfides and organic complexes. Vascular plants survive in saturated soils in part by pumping O2 into their root zones, changing their microenvironment to an oxic one. This, along with chelating exudates, mobilizes metals, allowing uptake by the roots. We compared

P Weis; L Windham; D. J Burke; J. S Weis

2002-01-01

280

GEOGRAPHIC VARIATION IN POSITIVE AND NEGATIVE INTERACTIONS AMONG SALT MARSH PLANTS  

Microsoft Academic Search

A pressing problem for ecologists is determining whether our understanding of communities, often developed from work at fine scales, can explain processes across broader scales. Here, we explore whether models of positive interactions developed in southern New England can be applied to geographic scales. Salt marsh plants may interact positively by ameliorating harsh physical conditions such as salinity stress. Because

Steven C. Pennings; Elizabeth R. Selig; Letise T. Houser; Mark D. Bertness

2003-01-01

281

Consumer pressure and seed set in a salt marsh perennial plant community  

Microsoft Academic Search

Seed predation can be an important determinant of plant success, but has received little attention in wetland plant communities. Here, we examine the role of flower and seed predators in limiting the seed production of the dominant perennial plants in a salt marsh plant community. Of the four perennial investigated, direct ovule loss to consumers ranged from 51 to 80%,

M. D. Bertness; C. Wise; A. M. Ellison

1987-01-01

282

Physiological ecology of acetylene reduction (nitrogen fixation) in a Delaware salt marsh  

Microsoft Academic Search

The effects of several fixed nitrogen compounds on acetylene reduction activity (nitrogen fixation) of surface sediments from a Delaware salt marsh were studied. Ammonia addition caused little decrease in activity early in the summer but resulted in a considerable decrease (85–95%) in activity late in the summer and early in the fall. Nitrate caused a near complete suppression of activity

Howard J. Dicker; David W. Smith

1980-01-01

283

Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary, China  

NASA Astrophysics Data System (ADS)

The structure and temporal variations of the fish community in salt marshes of Chinese estuaries are poorly understood. Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary was studied based on quarterly sampling surveys in July and November, 2004, and February and May, 2005. Fishes were collected by consecutive day and night samplings using fyke nets during the ebbing spring tides. A total of 25,010 individuals were caught during the study. 17 families and 33 species were documented, and the most species-rich family was Gobiidae. Three species, Synechogobius ommaturus, Chelon haematocheilus and Lateolabrax maculatus together comprised 95.65% of the total catch, which were also the most important commercial fishery species in the Yangtze River estuary. The fish community was dominated by juvenile individuals of estuarine resident species. Time of year significantly affected fish use of salt marshes, but no significant effects of diel periodicity on the fish community were found except for fish sampling in July. These findings indicate that salt marshes in the Yangtze River estuary may play important nursery roles for fish community.

Jin, Binsong; Fu, Cuizhang; Zhong, Junsheng; Li, Bo; Chen, Jiakuan; Wu, Jihua

2007-07-01

284

Spatial and seasonal variation in heavy metals in interstitial water of salt marsh soils  

Microsoft Academic Search

The composition of interstitial water collected from a salt marsh in NW Spain showed clear seasonal and spatial variations associated with redox cycles of Fe and S. In the summer, salinity increased in all soils as a consequence of the increase in evapotranspiration. The pH and concentrations of heavy metals also differed with season, but not all environments showed the

Xosé L. Otero; Felipe Mac??as

2002-01-01

285

A mixing-model approach to quantifying sources of organic matter to salt marsh sediments  

NASA Astrophysics Data System (ADS)

Salt marshes are highly productive ecosystems, where autochthonous production controls an intricate exchange of carbon and energy among organisms. The major sources of organic carbon to these systems include 1) autochthonous production by vascular plant matter, 2) import of allochthonous plant material, and 3) phytoplankton biomass. Quantifying the relative contribution of organic matter sources to a salt marsh is important for understanding the fate and transformation of organic carbon in these systems, which also impacts the timing and magnitude of carbon export to the coastal ocean. A common approach to quantify organic matter source contributions to mixtures is the use of linear mixing models. To estimate the relative contributions of endmember materials to total organic matter in the sediment, the problem is formulated as a constrained linear least-square problem. However, the type of data that is utilized in such mixing models, the uncertainties in endmember compositions and the temporal dynamics of non-conservative entitites can have varying affects on the results. Making use of a comprehensive data set that encompasses several endmember characteristics - including a yearlong degradation experiment - we study the impact of these factors on estimates of the origin of sedimentary organic carbon in a saltmarsh located in the SE United States. We first evaluate the sensitivity of linear mixing models to the type of data employed by analyzing a series of mixing models that utilize various combinations of parameters (i.e. endmember characteristics such as ?13COC, C/N ratios or lignin content). Next, we assess the importance of using more than the minimum number of parameters required to estimate endmember contributions to the total organic matter pool. Then, we quantify the impact of data uncertainty on the outcome of the analysis using Monte Carlo simulations and accounting for the uncertainty in endmember characteristics. Finally, as biogeochemical processes can alter endmember characteristics over time, we investigate the effect of early diagenesis on chosen parameters, an analysis that entails an assessment of the organic matter age distribution. Thus, estimates of the relative contributions of phytoplankton, C3 and C4 plants to bulk sediment organic matter depend not only on environmental characteristics that impact reactivity, but also on sediment mixing processes.

Bowles, K. M.; Meile, C. D.

2010-12-01

286

Methyl and Total Mercury Budget of a Mid-Atlantic Estuarine Salt Marsh  

NASA Astrophysics Data System (ADS)

Coastal and estuarine salt marshes are both efficient accumulators of particulate-bound inorganic mercury (Hg) and transformers of inorganic Hg to methylmercury (MeHg). As part of continuing studies on the biogeochemical controls, sources, and fate of Hg and MeHg in the Chesapeake Bay region, we have recently expanded our research to examine Hg and MeHg cycling in Chesapeake tidal marshes. Our main study site is the Kirkpatrick Marsh, a salt marsh at the Smithsonian Environmental Research Center (SERC) on the shores of a Chesapeake Bay sub-estuary, the Rhode River. Kirkpatrick Marsh is dominated by Spartina patens, Scirpus olneyi, Phragmites australis, and several other species and is influenced by a mean tidal range of approximately 30 cm. The marsh is currently and has previously been the subject of various biogeochemical studies, thus basic biogeochemistry, carbon, and nutrient cycling for this system is well understood. Research goals for our study include an estimation of the contribution of salt marshes to MeHg budgets in the Chesapeake specifically and in coastal zones more generally; a first look at the sources of Hg for methylmercury production in tidal marshes; and an improved understanding of the biogeochemical controls on net MeHg production and flux in these wetlands. The research study has two major components. One is a spatially-distributed investigation of the geochemical and microbial controls on MeHg production in this high sulfate/high sulfide wetland system. Detailed biogeochemical measurements were made across three marsh zones distinguished by vegetation/elevation characteristics. Microbial activity in the three zones peaks at depths approximately equal to the mean water table depth, but always in the upper 5-10 cm of soil. Pore water sulfide concentrations increase substantially with depth in marsh soil cores, with highest sulfide concentrations (up to 1.5 M) found deeper in the least frequently flooded site. Initial data show that MeHg concentrations are maximal in the top 5-10 cm of soil, right above the transition into high sulfide zones. In contrast to some other marine systems, our initial data reveals high MeHg concentrations (up to 2.5 ng/L) in marsh pore water across a wider range of sulfide concentrations between 5 and 400 uM. The other component of this research is the construction of comprehensive and temporally-intensive water, total mercury, and methylmercury budgets for the salt marsh. This includes local Hg deposition, continuous flow- weighted Hg/MeHg flux measurements through the main tidal channel, monthly Hg/MeHg measurements along a salinity gradient in the adjacent Rhode River, and various other hydrologic and climatologic measurements. Initial results indicate, as expected, that the marsh is a major sink for particulate bound Hg. Linking process scale measurements with larger-scale hydrology is a key step in attributing the source/sink characteristics of the marsh to spatial and temporal variability of processes within it.

Mitchell, C. P.; Gilmour, C. C.

2007-12-01

287

The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments  

PubMed Central

Methane (CH4) flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23??g CH4?m?2?day?1 for each g?N?m?2?year?1 applied) after 7?months of fertilization. To test the reason behind this increased CH4 flux, we conducted a microcosm experiment altering both nitrogen and carbon availability under aerobic and anaerobic conditions. Methanogenesis appeared to be both nitrogen and carbon (acetate) limited. N and C each increased methanogenesis by 18%, and together by 44%. In contrast, methanotrophy was stimulated by carbon (methane) addition (830%), but was unchanged by nitrogen addition. Sequence analysis of the sediment methylotroph community with the methanol dehydrogenase gene (mxaF) revealed three distinct clades that fall outside of known lineages. However, in agreement with the microcosm results, methylotroph abundance (assayed by qPCR) and composition (assayed by terminal restriction fragment length polymorphism analysis) did not vary across the experimental nitrogen gradient in the field. Together, these results suggest that nitrogen enrichment to salt marsh sediments increases methane flux by stimulating the methanogen community.

Irvine, Irina C.; Vivanco, Lucia; Bentley, Peris N.; Martiny, Jennifer B. H.

2012-01-01

288

Cattail invasion and persistence in a coastal salt marsh: The role of salinity reduction  

Microsoft Academic Search

The hypothesis thatTypha domingensis (cattail) can invade tidal marshes only after soil salinities are substantially reduced was tested experimentally by comparing\\u000a the salt tolerance of seeds, seedlings, and plants reared from rhizomes. Germination rates for four southern California populations\\u000a reached 100% in fresh water, decreasing to 2% at 20‰. The salt tolerance of seeds from three coastal populations was lower

Pamela A. Beare; Joy B. Zedler

1987-01-01

289

Comparison of vesicular-arbuscular mycorrhizae in plants from disturbed and adjacent undisturbed regions of a coastal salt marsh in Clinton, Connecticut, USA  

NASA Astrophysics Data System (ADS)

Roots of salt marsh plant species Spartina alterniflora, S. patens, Distichlis spicata, and others were examined for the presence of vesicular-arbuscular mycorrhizal (VAM) fungi. Samples were taken from introduced planted material in a salt marsh restoration project and from native material in adjacent marsh areas along the Indian River, Clinton, Connecticut, USA. After ten years the replanted area still has sites devoid of vegetation. The salt marsh plants introduced there were devoid of VAM fungi, while high marsh species from the adjacent undisturbed region showed consistent infection, leading the authors to suggest that VAM fungal infection of planting stocks may be a factor in the success of marsh restoration.

Cooke, John C.; Lefor, Michael W.

1990-01-01

290

Managing Salt Marshes for Mosquito Control: Impacts of Runnelling, Open Marsh Water Management and Grid-ditching in Sub-tropical Australia  

Microsoft Academic Search

Three salt marsh sites in south-east Queensland, Australia, have been modified for mosquito control. The problem species is\\u000a Ochlerotatus vigilax, a vector of Ross River virus that is an epidemic polyarthritic disease. All sites have similar vegetation and tidal influences.\\u000a Each site has a different form of modification to manage the mosquitoes: runnelling, Open Marsh Water Management (OMWM) and\\u000a grid-ditching.

Pat E. R. Dale; Jon M. Knight

2006-01-01

291

Seasonal Variability and Transport of Suspended Microfungi in a Southeastern Salt Marsh †  

PubMed Central

Tidally induced fluctuations and transports of microfungi were investigated. Samples were collected at three depths from three stations positioned at a transect in a large salt marsh creek. Samples were taken every 1.5 h for 50 consecutive h during neap tides and 50 consecutive h during the corresponding spring tides. In each season, microfungi concentrations fluctuated out of phase with the tides during both neap and spring tides. Mean concentrations of suspended microfungi did not vary appreciably throughout the year. Fungi were exported from the marsh during the majority of the tidal cycles studied. The results suggest that microfungi may serve as indicators of water mass movements.

Chrzanowski, Thomas H.; Stevenson, L. Harold; Spurrier, J. D.

1982-01-01

292

Ecology of irregularly flooded salt marshes of the northeastern Gulf of Mexico: a community profile  

SciTech Connect

The salt marshes of the northeastern Gulf of Mexico are distinguished by irregular flooding, low energy wave and tidal action, and long periods of exposure. The plant community is most often dominated by black needlerush (Juncus roemerianus), the species of focus in this synthesis. Distinct marsh zones include those dominated by Juncus and Spartina alterniflora at low elevations, sparsely vegetated salt flats, and higher elevation salt meadows of Juncus and Spartina patens. A diverse microbial and algal assemblage is also present. A diverse fauna has adapted to the physical rigors of these marshes. Zooplankton are dominated by the larvae of fiddler crabs and other decapods. The meiofauna consist primarily of nematodes and harpacticoid copepods. Macroinvertebrates are represented by crustaceans (especially mollusks and crabs), annelids, and insects. Grass shrimp, blue crabs, and other crustaceans are seasonally abundant in marsh creeks, as are a number of resident and migratory fish species. Birds comprise one of the larger herbivore groups and are also significant at higher tropic levels as top carnivores. Muskrat and nutria are important mammals. 43 figs., 38 tabs.

Stout, J.P.

1984-12-01

293

Temporal and spatial relationships between watershed land use and salt marsh disturbance in a pacific estuary.  

PubMed

Historical and recent remote sensing data can be used to address temporal and spatial relationships between upland land cover and downstream vegetation response at the watershed scale. This is demonstrated for sub-watersheds draining into Elkhorn Slough, California, where salt marsh habitat has diminished because of the formation of sediment fans that support woody riparian vegetation. Multiple regression models were used to examine which land cover variables and physical properties of the watershed most influenced sediment fan size within 23 sub-watersheds (1.4 ha to 200 ha). Model explanatory power increased (adjusted R(2) = 0.94 vs. 0.75) among large sub-watersheds (>10 ha) and historical watershed variables, such as average farmland slope, flowpath slope, and flowpath distance between farmland and marsh, were significant. It was also possible to explain the increase in riparian vegetation by historical watershed variables for the larger sub-watersheds. Sub-watershed area is the overriding physical characteristic influencing the extent of sedimentation in a salt marsh, while percent cover of agricultural land use is the most influential land cover variable. The results also reveal that salt marsh recovery depends on relative cover of different land use classes in the watershed, with greater chances of recovery associated with less intensive agriculture. This research reveals a potential delay between watershed impacts and wetland response that can be best revealed when conducting multi-temporal analyses on larger watersheds. PMID:17106797

Byrd, Kristin B; Kelly, N Maggi; Merenlender, Adina M

2006-11-14

294

Energy filter properties of ecosystems. [New Zealand marshes  

SciTech Connect

The role of ecosystem structure and function in absorbing energy inputs was developed using wave filter concepts combining ecology and communications engineering. Analysis techniques used to trace signals and energy through linear systems are applied to nonlinear ecosystem models in 1005 simulation runs. The energy absorbed by different designs was simulated separating mean power and that due to variation about the mean, variant power. Where more energy absorption generates more potential for success, then these designs may be favored in survival. More power was used by linear competition at low energy input and autocatalytic competition at high energy input. In general, trophic chain models with increasing secondary positive feedbacks in multiplicative interactions transformed more power but were less stable. Simulation of four turnover arrangements in a three unit trophic chain model showed that hierarchically arranged turnovers (Q/sub 1/ = 10, Q/sub 2/ = 1, Q/sub 3/ = 0.1) were the most stable (82.7% of the time) and used the most power (37.6% of the time).

Campbell, D.E.

1984-01-01

295

Spartina alterniflora genotype influences facilitation and suppression of high marsh species colonizing an early successional salt marsh  

USGS Publications Warehouse

1. Genetically based phenotypic and ecotypic variation in a dominant plant species can influence ecological functions and patterns of recruitment by other species in plant communities. However, the nature and degree of importance of genotypic differences is poorly understood in most systems. 2. The dominant salt marsh species, Spartina alterniflora, is known to induce facultative and competitive effects in different plant species, and the outcomes of interactions can be affected by nutrients and flooding stress. Clonal genotypes, which maintained their different plant architecture phenotypes throughout 31 months of a field experiment, underwent considerable genet-specific senescence in their centres over the last 12 months. 3. Different clonal genotypes and different locations (robust edges vs. senescent centres) permitted significantly different levels of light penetration of the canopy (14.8-77.6%), thus establishing spatial heterogeneity for this important environmental factor. 4. S. alterniflora clonal genotype influenced the degree of suppression of the previously dominant Salicornia bigelovii as well as facilitation of recruitment and growth by other plant species. Aster subulatus and Atriplex, patula performed better in Spartina clone centres, and experienced reduced growth in Salicornia-dominated areas. 5. Four other high marsh species (Borrichia frutescens, Aster tenuifolius, Iva frutescens and Limonium carolinianum) colonized only into Spartina clones but not into the Salicornia-dominated area. 6. These results suggest that differences in clone size, centre senescence, stem density, height, total stem length and biomass in different genotypes of a dominant marsh plant species can influence recruitment and growth of other plant species. The spatial pattern of habitat heterogeneity is, at least in part, dependent on the genotypic diversity, and possibly the genetic diversity, of such foundation species. 7. We hypothesize that as genotypic diversity increases in populations of a dominant plant species like S. alterniflora, the number and diversity of interactions with other species will increase as well. ?? 2005 British Ecological Society.

Proffitt, C. E.; Chiasson, R. L.; Owens, A. B.; Edwards, K. R.; Travis, S. E.

2005-01-01

296

The Role of Tidal Salt Marsh as an Energy Source for Marine Transient and Resident Finfishes: A Stable Isotope Approach  

Microsoft Academic Search

Stable isotope ratios of carbon, nitrogen, and sulfur (?C, ?N, and ?S) in bay anchovy Anchoa mitchilli and white perch Morone americana from Delaware Bay were a function of capture location and, for restored tidal salt marshes, possibly a function of the relative position of the marsh restoration trajectory. White perch collected in polyhaline restoration and reference (Moore's Beach) sites

Michael P. Weinstein; Steven Y. Litvin; Keith L. Bosley; Charlotte M. Fuller; Sam C. Wainright

2000-01-01

297

Experiencing the salt marsh environment through the foot of Littoraria irrorata: Behavioral responses to thermal and desiccation stresses  

Microsoft Academic Search

Behavioral responses to environmental conditions can determine both the microclimate surrounding an organism, as well as how an organism experiences that microclimate. The salt marsh snail Littoraria irrorata (Say) employs two types of behaviors that potentially affect its likelihood of experiencing thermal and\\/or desiccation stress: 1) retracting its foot into its shell and 2) vertically migrating on the marsh grass

Josephine C. Iacarella; Brian Helmuth

298

The Growth Rate of Fundulus Heteroclitus: A Comparative Study of two Virginia Salt Marshes.  

NASA Astrophysics Data System (ADS)

The growth rate of Fundulus heteroclitus (mummichog) was determined in a comparative study of Virginia tidal salt marshes. Two marshes in close geographic proximity were selected, one was considered pristine (natural) and the other impacted (urban). Monthly sampling was conducted during November 1999 and February 2000 and biweekly during May 2000 through September 2000. Stratified random samples of mummichogs were collected and brought back to the lab for otolith extraction and age determination. All other nekton were identified, measured, and enumerated. Marginal increment analysis was used to validate the use of otoliths in determining the age of mummichogs. Annulus formation was determined to occur annually; therefore counts of annuli obtained were valid and truly reflected the age of mummichogs. Difference in growth was found to exist between mummichogs from the natural and urban marshes. In the natural marsh, mummichogs grew 0.13 mm/day at age 0, 0.04 mm/day at age 1 and 0.13 mm/day at age 2. In the urban marsh, mummichogs grew 0.22 mm/day at age 0, 0.09 mm/day at age 1 and 0.13 mm/day at age 2.

Holloman, E. L.; Bodolus, D.

2004-12-01

299

Habitat utilization and alteration by the invasive burrowing isopod, Sphaeroma quoyanum, in California salt marshes  

Microsoft Academic Search

In recent years the pace of exotic species introduction and invasion has accelerated, particularly in estuaries and wetlands.\\u000a Species invasions may affect coastal ecosystems in many ways. Alteration of sedimentary environments, through structure formation\\u000a and burrowing, has particularly dramatic effects on coastal habitats. This study examines modification of channel bank and\\u000a marsh edge habitat by the burrowing Australasian isopod Sphaeroma

T. S. Talley; J. A. Crooks; L. A. Levin

2001-01-01

300

The Effects of Ditching on the Mosquito Populations in Some Sections of 'Juncus' Salt Marsh in Carteret County, North Carolina.  

National Technical Information Service (NTIS)

Five areas of irregularly flooded salt marsh were studied to determine effects of ditching on mosquito populations. Principal species were Anopheles atropos, Anopheles bradleyi, Aedes sollicitans, and Aedes taeniorhynchus. Present in lesser numbers were C...

R. N. LaSalle K. L. Knight

1973-01-01

301

Sediment quality assessment in tidal salt marshes in northern California, USA: an evaluation of multiple lines of evidence approach.  

PubMed

The objective of this study was to evaluate the efficacy of integrating a traditional sediment quality triad approach with selected sublethal chronic indicators in resident species in assessing sediment quality in four salt marshes in northern California, USA. These included the highly contaminated (Stege Marsh) and relatively clean (China Camp) marshes in San Francisco Bay and two reference marshes in Tomales Bay. Toxicity potential of contaminants and benthic macroinvertebrate survey showed significant differences between contaminated and reference marshes. Sublethal responses (e.g., apoptotic DNA fragmentation, lipid accumulation, and glycogen depletion) in livers of longjaw mudsucker (Gillichthys mirabilis) and embryo abnormality in lined shore crab (Pachygrapsus crassipes) also clearly distinguished contaminated and reference marshes, while other responses (e.g., cytochrome P450, metallothionein) did not. This study demonstrates that additional chronic sublethal responses in resident species under field exposure conditions can be readily combined with sediment quality triads for an expanded multiple lines of evidence approach. This confirmatory step may be warranted in environments like salt marshes in which natural variables may affect interpretation of toxicity test data. Qualitative and quantitative integration of the portfolio of responses in resident species and traditional approach can support a more comprehensive and informative sediment quality assessment in salt marshes and possibly other habitat types as well. PMID:23542672

Hwang, Hyun-Min; Carr, R Scott; Cherr, Gary N; Green, Peter G; Grosholz, Edwin D; Judah, Linda; Morgan, Steven G; Ogle, Scott; Rashbrook, Vanessa K; Rose, Wendy L; Teh, Swee J; Vines, Carol A; Anderson, Susan L

2013-03-28

302

Distribution of natural uranium, thorium, lead, and polonium radionuclides in tidal phases of a Delaware salt marsh  

Microsoft Academic Search

Natural radionuclides in the uranium and thorium series were measured in solid tidal phases (suspended particles, bottom sediment,\\u000a surface microlayer colloids) of a salt marsh in lower Delaware. The purpose was to identify potential processes responsible\\u000a for trace element cycling (sources, redistribution and exchange) in salt water marshes and with their coastal waters. Generally,\\u000a concentrations of U, Th,210Pb, and210Po on

T. M. Church; M. Bernat; P. Sharma

1986-01-01

303

Mangrove encroachment of salt marsh in Western Port Bay, Victoria: The role of sedimentation, subsidence, and sea level rise  

Microsoft Academic Search

Surface elevation tables, feldspar marker horizons, and210Pb analysis of core profiles were implemented at four sites in Western Port Bay, Victoria, Australia, to provide information\\u000a on the role of sedimentation, subsidence or compaction, and enhanced sea-level rise in contributing to salt marsh decline.\\u000a Photogrammetric surveys indicate that the rate of salt marsh decline that is attributable to mangrove encroachment is

K. Rogers; N. Saintilan; H. Heijnis

2005-01-01

304

The abundance and life histories of terrestrial isopods in a salt marsh of the Ria Formosa lagoon system, southern Portugal  

Microsoft Academic Search

Four species of isopod characteristic of salt marsh habitats, Tylos ponticus, Porcellio lamellatus, Halophiloscia couchii and Armadillidium album coexist in the upper reaches of the Ria Formosa lagoon salt marsh system in southern Portugal. In this locality, T. ponticus is the most abundant of the four species with mean annual densities of 2,950 m?2 and a peak density of 10,387 m?2 in

N. Dias; M. Sprung; M. Hassall

2005-01-01

305

Differential effects of salinity and soil saturation on native and exotic plants of a coastal salt marsh  

Microsoft Academic Search

In many southern California salt marshes, increased freshwater inflows have promoted the establishment of exotic plant species.\\u000a A comparative study showed that a native, perennial, high marsh dominant,Salicornia subterminalis, and an invasive, exotic annual grass,Polypogon monspeliensis, responded differently to soil salinity and saturation.Salicornia subterminalis seeds and young plants were more salt tolerant, and the native grew best at high salinities

Nathan L. Kuhn; Joy B. Zedler

1997-01-01

306

Beneath the Salt Marsh Canopy: Loss of Soil Strength with Increasing Nutrient Loads  

Microsoft Academic Search

Although the broadly observed increase in nutrient loading rates to coastal waters in the last 100 years may increase aboveground\\u000a biomass, it also tends to increase soil metabolism and lower root and rhizome biomass—responses that can compromise soil strength.\\u000a Fourteen different multiyear field combinations of nutrient amendments to salt marshes were made to determine the relationship\\u000a between soil strength and various

R. Eugene Turner

2011-01-01

307

Seasonal Variability of Diazotroph Assemblages Associated with the Rhizosphere of the Salt Marsh Cordgrass, Spartina alterniflora  

Microsoft Academic Search

Nitrogen fixation is the primary N source in the highly productive but N-limited North Inlet, SC, USA salt marsh system. The\\u000a diverse assemblages of nitrogen-fixing (diazotrophic) bacteria associated with the rhizospheres of the short and tall growth\\u000a forms of Spartina alterniflora were analyzed at two sites, Crab Haul Creek and Goat Island, which are in different tidal creek drainage systems

Megan D. Gamble; Christopher E. Bagwell; Jeannine LaRocque; Peter W. Bergholz; Charles R. Lovell

2010-01-01

308

Denitrification in salt marsh sediments: Evidence for seasonal temperature selection among populations of denitrifiers  

Microsoft Academic Search

Direct measurements of bacterial denitrification in salt marsh sediments near Woods Hole, Massachusetts were made over a 10-month period using a simple and precise gas-chromatographic technique. Based on laboratory experiments at 5°, 10°, and 20°C, it is shown that seasonal temperature variations select for at least two distinct populations of denitrifiers.In situ incubations suggest that resident populations of denitrifying bacteria

Warren A. Kaplan; John M. Teal; Ivan Valiela

1977-01-01

309

Effects of Monospecific Banks of Salt Marsh Vegetation on Sediment Bacterial Communities  

Microsoft Academic Search

The aim of this study was to understand if two species of salt marsh plants, widely distributed in European estuaries (Spartina maritima and Halimione portulacoides) differently influence the distribution, activity, and metabolic physiology of sediment bacterial communities in monospecific\\u000a banks, in comparison with uncolonized sediment (control). Microbiological descriptors of abundance and activity were assessed\\u000a along vertical profiles of sediments. Rates

Vanessa Oliveira; Ana L. Santos; Francisco Coelho; Newton C. M. Gomes; Helena Silva; Adelaide Almeida; Ângela Cunha

2010-01-01

310

Oxygen loss from Spartina alterniflora and its relationship to salt marsh oxygen balance  

Microsoft Academic Search

Spartina alterniflora has been reported to lose significant amounts of oxygen to its rhizosphere with potentially important effects on salt-marsh biogeochemical cycling and plant productivity. The potential significance of this oxidative pathway was evaluated using laboratory split-chamber experiments to quantify oxygen loss from intact root systems under a wide variety of pre-treatment and incubation conditions including antibiotics to inhibit microbial

B. L. Howes; J. M. Teal

1994-01-01

311

Oxygen demand and sulfate reduction in petroleum hydrocarbon contaminated salt marsh soils  

Microsoft Academic Search

Laboratory studies were conducted using salt marsh cores to determine the oxygen demand exerted by spilled crude oil and fertilizers added to stimulate biodegradation. Measurements of oxygen uptake and CO2 efflux in flooded and non-flooded cores were conducted in addition to measurements of the magnitude and depth distribution of sulfate reduction rates using 35SO2?4. Additions of crude oil and fertilizers

Won Sik Shin; John H. Pardue; W. Andrew Jackson

2000-01-01

312

Naked Amoebas and Bacteria in an Oil-Impacted Salt MarshCommunity  

Microsoft Academic Search

  Populations of soil amoebas were monitored in two salt marshes in Staten Island, NY for 2 years. One site, Gulfport Reach\\u000a on the Arthur Kill, has been highly impacted by numerous oil spills. In particular, in 1990 a massive no. 2 fuel oil spill\\u000a from a ruptured pipe flooded the area; its sediments had total petroleum hydrocarbon (TPH) concentrations in

O. R. Anderson; T. Gorrell; A. Bergen; R. Kruzansky; M. Levandowsky

2001-01-01

313

Catastrophic events reveal the dynamic nature of salt-marsh vegetation in Southern California  

Microsoft Academic Search

Recent hydrological disturbances, including flooding, dry-season streamflow, and drought, greatly altered coastal wetland\\u000a habitats in sourthern California. At Tijuana Estuary, a six-year study of salt-marsh vegetation patterns during these rare\\u000a conditions documented substantial temporal variability in plant growth and distribution. Important to cordgrass (Spartina foliosa Trin.) dynamics were the amount and timing of streamflows, which reduced soil salinity and alleviated

Joy B. Zedler; Jordan Covin; Chris Nordby; Phil Williams; John Boland

1986-01-01

314

Hurricane signals in salt marsh sediments: Inorganic sources and soil volume  

Microsoft Academic Search

Abstract The inorganic,content of 51 dated sediment,cores from,Mississippi River deltaic plain salt marsh,wetlands peaks with the landfall of hurricanes. Variations in the inorganic sediment content,demonstrate,no temporal coherence with changes in either the Mississippi River suspended matter concentration or discharge, or with wetland losses on this coast. The inorganic matter brought,to wetlands,during hurricanes is sufficient to account for the accumulated inorganic

R. Eugene Turner; Erick M. Swenson; Charles S. Milan; James M. Lee

2007-01-01

315

Metal levels in sediments from the Minho estuary salt marsh: a metal clean area?  

Microsoft Academic Search

Total-recoverable metals (Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in sediments from Minho estuary salt marsh were determined to\\u000a evaluate possible increase in anthropogenic contamination by metals and to evaluate the possibility of this area to be considered\\u000a a pristine area in terms of metals, which can be used as a reference site for other metal-contaminated national and

Pedro A. Reis; José C. Antunes; C. Marisa R. Almeida

2009-01-01

316

Relation between heavy metal concentrations in salt marsh plants and soil.  

PubMed

The aim of the research reported here was to investigate the relation between heavy metal concentrations in salt marsh plants, extractability of the metals from soil and some soil characteristics. In April 1987, Spartina anglica and Aster tripolium plants and soil were collected from four salt marshes along the Dutch coast. The redox potential of the soil between the roots of the plants and at bare sites was measured. Soil samples were oven-dried and analyzed for chloride concentration, pH, fraction of soil particles smaller than 63 microm (f < 63 microm), loss on ignition (LOI) and ammonium acetate and hydrochloric acid extractable Cd, Cu and Zn concentrations. The roots and shoots of the plants were analyzed for Cd, Cu and Zn. Because drying of the soil prior to chemical analysis might have changed the chemical speciation of the metals, and therefore the outcome of the ammonium acetate extraction, a second survey was performed in October 1990. In this survey A. tripolium plants and soil were collected from two salt marshes. Fresh and matched oven-dried soil samples were analyzed for water, ammonium acetate and diethylene triaminepentaacetic acid (DTPA) extractable Cd, Cu and Zn concentrations. The soil samples were also analyzed for f < 63 microm, LOI and total (HNO(3)/HCl digestion) metal concentrations. Soil metal concentrations were correlated with LOI. Drying prior to analysis of the soil had a significant effect on the extractability of the metals with water, ammonium acetate or DTPA. Plant metal concentrations significantly correlated only with some extractable metal concentrations determined in dried soil samples. However, these correlations were not consistently better than with total metal concentrations in the soil. It was concluded that extractions of metals from soil with water, ammonium acetate or DTPA are not better predictors for metal concentrations in salt marsh plants than total metal concentrations, and that a major part of the variation in metal concentrations in the plants cannot be explained by variation in soil composition. PMID:15091794

Otte, M L; Haarsma, M S; Broekman, R A; Rozema, J

1993-01-01

317

Temporal and Spatial Relationships Between Watershed Land Use and Salt Marsh Disturbance in a Pacific Estuary  

Microsoft Academic Search

Historical and recent remote sensing data can be used to address temporal and spatial relationships between upland land cover\\u000a and downstream vegetation response at the watershed scale. This is demonstrated for sub-watersheds draining into Elkhorn Slough,\\u000a California, where salt marsh habitat has diminished because of the formation of sediment fans that support woody riparian\\u000a vegetation. Multiple regression models were used

Kristin B. Byrd; N. Maggi Kelly; Adina M. Merenlender

2007-01-01

318

Evaluation of alternative oil spill cleanup techniques in a Spartina alterniflora salt marsh.  

PubMed

Three oil spill situations which cause long-term impact were simulated in 1 m(2) salt marsh plots to evaluate the effectiveness of alternative cleanup techniques at removing oil and reducing damage to Spartina alterniflora. Cleanup techniques, implemented 18-24 h after oiling, were not effective at removing oil after sediment penetration. When oil remained on the sediment surface, flushing techniques were most effective at removal, reducing levels of added oil by 73% to 83%. The addition of dispersant to the flushing stream only slightly enhanced oil removal. Clipping of vegetation followed by sorbent pad application to sediment was moderately effective, reducing added oil by 36% to 44%. In contrast to flushing and clipping, burning increased the amount of oil in sediment by 27% to 72%. Although flushing and clipping were effective at oil removal, neither technique reduced initial damage to plants or enhanced long-term recovery. While flushed plots sustained no additional plant damage due to cleanup, clipped and burned plots sustained additional initial plant damage. Based on these results, first considerations should be given to natural tidal flushing as the means to remove oil, especially in salt marshes subject to ample tidal inundation. Although our results do not support cleanup in salt marshes with ample tidal inundation, low pressure flushing may be warranted when fuel oils or large quantities of crude oil impact salt marshes subject to reduced tidal flushing. Flushing, when warranted, should be initiated prior to oil penetration into the substrate. Clipping may be considered as a cleanup response only when heavy oil cannot be effectively removed from vegetation by flushing. Burning is not recommended because it enhances oil penetration into sediment and causes substantial initial plant damage. PMID:15092503

Kiesling, R W; Alexander, S K; Webb, J W

1988-01-01

319

Latitudinal Variation in Palatability of Salt-Marsh Plants: Which Traits Are Responsible?  

Microsoft Academic Search

Abstract. Biogeographic,theory,predicts that intense consumer?prey,interactions at low,latitudes should,select for increased,defenses,of prey relative to high latitudes. In salt marshes on the Atlantic coast of the United States, a community-wide pattern exists in which,10 species of low-latitude plants are less palatable to a diverse suite of herbivores than are high-latitude conspecifics. Examination of proximate plant traits (toughness, pal- atability of polar and

Erin L. Siska; Steven C. Pennings; Tracy L. Buck; M. Dennis Hanisak

2002-01-01

320

From the salt marsh to the ID-card: Bacteriorhodopsin as a functional material in nanobiotechnology  

Microsoft Academic Search

Bacteriorhodopsin (BR) is an evolutionary highly optimized photochromic retinal protein, which is found in extremely halophilic\\u000a bacteria, e.g., in salt marshes. We demonstrated that starting from the wildtype as a blueprint by means of gene technology\\u000a and biotechnology a versatile material for optical information recording can be developed. BR is structurally related to the\\u000a visual pigment rhodopsin. It is the

Norbert A. Hampp

2005-01-01

321

Phylogenetic Diversity of Archaea in Sediment Samples from a Coastal Salt Marsh  

Microsoft Academic Search

The Archaea present in salt marsh sediment samples from a tidal creek and from an adjacent area of vegetative marshland, both of which showed active methanogenesis and sulfate reduction, were sampled by using 16S rRNA gene libraries created with Archaea-specific primers. None of the sequences were the same as reference sequences from cultured taxa, although some were closely related to

MARK A. MUNSON; DAVID B. NEDWELL; T. MARTIN EMBLEY

1997-01-01

322

Restoring assemblages of salt marsh halophytes in the presence of a rapidly colonizing dominant species  

Microsoft Academic Search

Establishing species-rich plant communities is a common goal of habitat restoration efforts, but not all species within a\\u000a target assemblage have the same capacity for recruitment and survival in created habitats. We investigated the development\\u000a of a tidal salt marsh plant community in the presence of a rapidly colonizing dominant species, Salicornia virginica, in a newly created habitat in Mugu

Anna R. Armitage; Katharyn E. Boyer; Richard R. Vance; Richard F. Ambrose

2006-01-01

323

Archaeal Diversity and the Prevalence of Crenarchaeota in Salt Marsh Sediments?  

PubMed Central

Crenarchaeal 16S rRNA sequences constituted over 70% of the archaeal clones recovered from three salt marsh sites dominated by different grasses. Group I.1a Crenarchaeota dominated at two sites, while group I.3b Crenarchaeota sequences were most abundant at a third site. Abundances of 16S rRNA genes related to “Candidatus Nitrosopumilus maritimus” differed by site and sampling date.

Nelson, Katelyn A.; Moin, Nicole S.; Bernhard, Anne E.

2009-01-01

324

Ecosystem response to changes in water level of Lake Ontario marshes: lessons from the restoration of Cootes Paradise Marsh  

Microsoft Academic Search

A general understanding of how aquatic vegetation responds to water-level fluctuations is needed to guide restoration of Great Lakes coastal wetlands because inter-annual and seasonal variations often confound effects of costly remedial actions. In 1997, common carp (Cyprinus carpio) was removed from Cootes Paradise Marsh (L. Ontario) to reduce sediment resuspension and bioturbation, and thus regenerate marsh plants that had

Patricia Chow-Fraser

2005-01-01

325

137Cs in the Danish Wadden Sea: contrast between tidal flats and salt marshes.  

PubMed

The 137Cs activity of salt marsh and tidal flat sediments of the northern part of the European Wadden Sea was studied based on a comprehensive dataset of 210Pb dated cores. The 137Cs inventory of salt marsh sediments shows a major peak corresponding to the Chernobyl accident in 1986, and a minor peak located in the late 1960s interpreted as the combined effect of atmospheric testing of nuclear weapons. Emissions from the nuclear reprocessing plant Sellafield are not reflected as peaks in 137Cs activity, but may contribute to the rising 137Cs activity in the years prior to 1986. The 137Cs activity of tidal flat sediments differs from salt marsh sediment in two respects. First, the activity is much lower and, second, the major peak in the 1980s is located in the beginning instead of in the middle of the decade. The differences in 137Cs inventory between the two environments are interpreted to result from repeated cycles of deposition/resuspension and mixing on tidal flats. A simple model illustrating the consequence of mixings returns an apparent shift of major peaks in 137Cs activities backwards in time corresponding to the mixing depth divided by the deposition rate. PMID:17449152

Pedersen, Jørn B T; Bartholdy, Jesper; Christiansen, Christian

2007-04-20

326

Bacterial community response to petroleum contamination and nutrient addition in sediments from a temperate salt marsh.  

PubMed

Microbial communities play an important role in the biodegradation of organic pollutants in sediments, including hydrocarbons. The aim of this study was to evaluate the response of temperate salt marsh microbial communities to petroleum contamination, in terms of community structure, abundance and capacity to degrade hydrocarbons. Sediments un-colonized and colonized (rhizosediments) by Juncus maritimus, Phragmites australis and Triglochin striata were collected in a temperate estuary (Lima, NW Portugal), spiked with petroleum under variable nutritional conditions, and incubated for 15 days. Results showed that plant speciation emerged as the major factor for shaping the rhizosphere community structure, overriding the petroleum influence. Moreover, when exposed to petroleum contamination, the distinct salt marsh microbial communities responded similarly with (i) increased abundance, (ii) changes in structure, and (iii) decreased diversity. Communities, particularly those associated to J. maritimus and P. australis roots displayed a potential to degrade petroleum hydrocarbons, with degradation percentages between 15% and 41%, depending on sediment type and nutritional conditions. In conclusion, distinct salt marsh microbial communities responded similarly to petroleum contamination, but presented different pace, nutritional requirements, and potential for its biodegradation, which should be taken into account when developing bioremediation strategies. PMID:23707865

Ribeiro, Hugo; Mucha, Ana P; Almeida, C Marisa R; Bordalo, Adriano A

2013-05-22

327

Tracer Analysis of Methanogenesis in Salt Marsh Soils †  

PubMed Central

Differences in paths of carbon flow have been found in soils of the tall (TS) and short (SS) Spartina alterniflora marshes of Sapelo Island, Ga. Gaseous end products of [U-14C]glucose metabolism were 14CO2 and 14CH4 in the SS region and primarily 14CO2 in the TS region. Sulfate concentration did not demonstrably affect glucose catabolism or the distribution of end products in either zone. [U-14C]acetate was converted to 14CO2 and 14CH4 in the SS soils and almost exclusively to 14CO2 in the TS soils. Sulfate concentration did not affect acetate metabolism in the SS soils; however, a noticeable effect of sulfate dilution was seen in TS soils. Sulfate dilution in TS samples resulted in increased methane formation. Total glucose and acetate metabolism were similar in TS and SS soils despite differences in end products. A microbial community characterized by fermentative/sulfate-reducing processes has developed in TS soils as opposed to the fermentative/methanogenic/sulfate-reducing community found in SS soils.

King, Gary M.; Wiebe, W. J.

1980-01-01

328

Long-term effects of mercury in a salt marsh: hysteresis in the distribution of vegetation following recovery from contamination.  

PubMed

During four decades, the Ria de Aveiro was subjected to the loading of mercury from a chlor-alkali industry, resulting in the deposition of several tons of mercury in the sediments. The present study evaluates the impact of this disturbance and the recovery processes, temporally and spatially, by means of examining the richness of the species of salt marsh plants and mercury concentrations in sediments over the last fifty years. The temporal assessment showed that the mercury loading induced a shift in the species composition of the salt marsh from a non-disturbed salt marsh with higher species richness to an alternative state dominated by Phragmites australis. The horizontal assessment, through a mercury gradient, presents the same trend, indicating that P. australis is the species most tolerant to higher mercury concentrations, comparative to Halimione portulacoides, Arthrocnemum fruticosum, Triglochin maritima, Juncus maritimus and Scirpus maritimus. After the reduction of mercury discharges in 1994, the salt marsh shows a slowly return path recovery response. The hysteresis in the response results in the temporal gap between the reduction in mercury concentrations in the sediment and the salt marsh species richness response, comparatively to the existing diversity in the local reference marsh. PMID:18061237

Válega, M; Lillebø, A I; Pereira, M E; Duarte, A C; Pardal, M A

2007-12-03

329

Joint Geophysical and Hydrologic Constraints on Shallow Groundwater Flow Systems in Clastic Salt Marshes of the South Atlantic Bight  

NASA Astrophysics Data System (ADS)

Salt marsh systems play a critical role in buffering upland coastal areas from the influence of open saltwater bodies and in filtering contaminants that originate offshore or are flushed from uplands. For these reasons, it is important to understand the salt marsh hydrologic cycle, especially the interaction of groundwater and surface water across low-lying coastal fringes and the changes in physical, chemical, and ecological parameters across salinity gradients extending from upland to tidal creek to open water. For the past 5 years, we have conducted hydrogeophysical surveys (inductive EM and DC resistivity) and collected limited, coincident groundwater hydrologic data in clastic salt marshes throughout the South Atlantic Bight (SAB), stretching from South Carolina on the north to the Georgia-Florida border on the south. All of the marshes are dominated by Spartina and Juncus grasses and are cut by tidally-influenced creeks, but both the lithology and age of the marshes vary widely. For example, one highly homogeneous marsh study site has formed only within the past century, while most sites have existed for thousands of years and have laterally and vertically heterogeneous lithology. Geophysical images of the marsh subsurface and coincident monitoring of groundwater temperature, water level, and/or chemistry consistently show that marshes in the mixed energy environment of the middle part of the SAB (GCE LTER) tend to be dominated by submarsh discharge of freshwater to adjacent tidal creeks. In the South Carolina part of the SAB, we have greater evidence for seepage, particularly through biologically-created macropore networks and permeable sediment bodies that intersect tidal creeks. It is possible though that the South Carolina results are not so much 'universal' as reflective of local lithology. In a very young marsh near the Florida border, geophysical imaging implies a mixture of seepage and submarsh flow, and hydrologic data provide unequivocal proof that the near-surface marsh muds act as a low permeability barrier to downward penetration of tidal creek surface waters during periodic inundation of the marsh. Taken together, the results imply that subsurface freshwater bodies flowing beneath some salt marshes act as extensions of the classic freshwater lens that develops beneath uplands and help to resist saline intrusion toward uplands. Certain factors allow us to predict the occurrence of seepage, instead of submarsh flow, in SAB salt marshes with some degree of confidence. Where we have acquired time series, both the hydrogeophysical and hydrologic data suggest that groundwater transport processes are at approximate steady-state at the length scales (vertical and horizontal) and over the duration of our measurements.

Ruppel, C.; Fulton, P.; Schultz, G. M.; Castillo, L.; Bartlett, J.; Sibley, S.

2005-12-01

330

Movements and food habits of striped bass (Morone saxatilis) in Delaware Bay (USA) salt marshes: comparison of a restored and a reference marsh  

Microsoft Academic Search

There has been much recent interest in restoration of salt-marsh habitats to their natural structure and function. However,\\u000a the criteria for success of such restorations are not well-defined. As part of a larger program to evaluate the restoration\\u000a of a former salt-hay farm bordering Delaware Bay, New Jersey, USA, we monitored the response of a large predator, the striped\\u000a bass

M. Tupper; K. W. Able

2000-01-01

331

The Protective Role of Coastal Marshes: A Systematic Review and Meta-analysis  

Microsoft Academic Search

BackgroundSalt marshes lie between many human communities and the coast and have been presumed to protect these communities from coastal hazards by providing important ecosystem services. However, previous characterizations of these ecosystem services have typically been based on a small number of historical studies, and the consistency and extent to which marshes provide these services has not been investigated. Here,

Christine C. Shepard; Caitlin M. Crain; Michael W. Beck

2011-01-01

332

Potential uses of TerraSAR-X for mapping herbaceous halophytes over salt marsh and tidal flats  

NASA Astrophysics Data System (ADS)

This study presents a method and application results of mapping different halophytes over tidal flats and salt marshes using high resolution space-borne X-band synthetic aperture radar (SAR) that has been rarely used for salt marsh mapping. Halophytes in a salt marshes are sensitive to sea-level changes, sedimentation, and anthropogenic modifications. The alteration of the demarcations among halophyte species is an indicator of sea level and environmental changes within a salt marsh. The boundary of an herbaceous halophyte patch is, however, difficult to determine using remotely sensed data because of its sparseness. We examined the ecological status of the halophytes and their distribution changes using TerraSAR-X and optical data. We also determined the optimum season for halophyte mapping. An annual plant, Suaeda japonica (S. japonica), and a typical perennial salt marsh grass, Phragmites australis (P. australis), were selected for halophyte analysis. S. japonica is particularly sensitive to sea level fluctuation. Seasonal variation for the annual plant was more significant (1.47 dB standard deviation) than that for the perennial grass, with a pattern of lower backscattering in winter and a peak in the summer. The border between S. japonica and P. australis was successfully determined based on the distinctive X-band radar backscattering features. Winter is the best season to distinguish between the two different species, while summer is ideal for analyzing the distribution changes of annual plants in salt marshes. For a single polarization, we recommend using HH polarization, because it produces maximum backscattering on tidal flats and salt marshes. Our results show that high resolution SAR, such as TerraSAR-X and Cosmo-SkyMed, is an effective tool for mapping halophyte species in tidal flats and monitoring their seasonal variations.

Lee, Yoon-Kyung; Park, Jeong-Won; Choi, Jong-Kuk; Oh, Yisok; Won, Joong-Sun

2012-12-01

333

MAPPING AND MONITORING OF SALT MARSH VEGETATION AND TIDAL CHANNEL NETWORK FROM HIGH RESOLUTION IMAGERY (1975-2006). EXAMPLE OF THE MONT-SAINT-MICHEL BAY (FRANCE)  

NASA Astrophysics Data System (ADS)

Coastal landscapes are severely affected by environmental and social pressures. Their long term development is controlled by both physical and anthropogenic factors, which spatial dynamics and interactions may be analysed by Earth Observation data. The Mont-Saint-Michel Bay (Normandy, France) is one of the European coastal systems with a very high tidal range (approximately 15m during spring tides) because of its geological, geomorphological and hydrodynamical contexts at the estuary of the Couesnon, Sée and Sélune rivers. It is also an important touristic place with the location of the Mont-Saint-Michel Abbey, and an invaluable ecosystem of wetlands forming a transition between the sea and the land. Since 2006, engineering works are performed with the objective of restoring the maritime character of the Bay. These works will lead to many changes in the spatial dynamics of the Bay which can be monitored with two indicators: the sediment budget and the wetland vegetation surfaces. In this context, the aim of this paper is to map and monitor the tidal channel network and the extension of the salt marsh vegetation formation in the tidal zone of the Mont-Saint-Michel Bay by using satellite images. The spatial correlation between the network location of the three main rivers and the development of salt marsh is analysed with multitemporal medium (60m) to high spatial resolution (from 10 to 30 m) satellite images over the period 1975-2006. The method uses a classical supervised algorithm based on a maximum likelihood classification of eleven satellites images. The salt-marsh surfaces and the tidal channel network are then integrated in a GIS. Results of extraction are assessed by qualitative (visual interpretation) and quantitative indicators (confusion matrix). The multi-temporal analysis between 1975 and 2006 highlights that in 1975 when the study area is 26000 ha, salt marshes cover 16% (3000ha), the sandflat (slikke) and the water represent respectively 59% and 25% of the area. In 2006, salt marshes represent more than 3900 ha. Then, in thirty years, salt marshes have increased in average of 29 ha.yr-1. Several periods with different speed can be identified. Moreover, if the global tendency is a progression of salt-marshes, three period of accretion are noticed. Some hypothesis can be formulated about the tidal channel migrations using various data sources as tide levels, wind wave and meteorological data and river discharges. This analysis showed that satellite images are an important information source to locate morphological coastal changes and allows to perform the understanding of a dynamic and complex system such as the Mont-Saint-Michel Bay. It is possible to extract and to monitor coastal objects over a long time series with heterogeneous data such as satellite images with different spatial and spectral resolutions. With the multiplication of very high spatial resolution images, the detection of salt marshes surfaces and tidal channel could ever be more accurate.

Puissant, A. P.; Kellerer, D.; Gluard, L.; Levoy, F.

2009-12-01

334

Polychlorinated biphenyls in two salt marsh sediments of the Venice Lagoon.  

PubMed

Polychlorinated biphenyls (PCBs) were measured in two dated salt marsh cores of the Venice Lagoon to assess their input chronology and to evaluate the importance of atmospheric deposition as a source. Sampling sites were chosen in order to evidence the differences between areas located leeward and windward with respect to inputs originating in both the city of Venice and the industrial area. Concentrations of PCB indicators (0.13-15.6 ng g?¹) increased gradually from the 1930s, reached maxima from the 1950s to the late 1970s, and then decreased. PCB loadings to marshes are driven by both the atmospheric deposition and the resuspension of subtidal sediments, this latter being more important for heavier congeners. The downwind marsh recorded higher fluxes (0.06-9.72 ng cm?² year?¹) than the upwind one (0.01-0.53 ng cm?² year?¹). Recent fluxes are rather consistent with bulk deposition measurements. A higher contribution of CB-101 and CB-118 was detected in the intermediate layers of the downwind site, suggesting a different PCB source for the corresponding time interval. In the other marsh, PCBs showed a rather constant composition at all levels (mostly CB-153, CB-138 and CB-180), accounting for a regional influence. Deep layers showed an enrichment of higher chlorinated congeners at both sites, whereas recent samples conserve the patterns typical of surficial and subsurficial subtidal sediments. The scientific approach adopted in this research can be considered as a sort of methodological procedure for the determination of fluxes and pathways of PCBs through the study of marsh cores. PMID:21165695

Mugnai, Cristian; Giuliani, Silvia; Bellucci, Luca G; Carraro, Claudio; Favotto, Maurizio; Frignani, Mauro

2010-12-17

335

Mobility of Pb in salt marshes recorded by total content and stable isotopic signature.  

PubMed

Total lead and its stable isotopes were analysed in sediment cores, leaves, stem and roots of Sacorconia fruticosa and Spartina maritima sampled from Tagus (contaminated site) and Guadiana (low anthropogenic pressure) salt marshes. Lead concentration in vegetated sediments from the Tagus marsh largely exceeded the levels in non-vegetated sediments. Depth profiles of (206)Pb/(207)Pb and (206)Pb/(208)Pb showed a decrease towards the surface ((206)Pb/(207)Pb=1.160-1.167) as a result of a higher proportion of pollutant Pb components. In contrast, sediments from Guadiana marsh exhibited low Pb concentrations and an uniform isotopic signature ((206)Pb/(207)Pb=1.172+/-0.003) with depth. This suggests a homogeneous mixing of mine-derived particles and pre-industrial sediments with minor inputs of anthropogenic Pb. Lead concentrations in roots of plants from the two marshes were higher than in leaves and stems, indicating limited transfer of Pb to aerial parts. A similar Pb isotopic signature was found in roots and in vegetated sediments, indicating that Pb uptake by plants reflects the input in sediments as determined by a significant anthropogenic contribution of Pb at Tagus and by mineralogical Pb phases at Guadiana. The accumulation in roots from Tagus marsh (max. 2870 microg g(-1) in S. fruticosa and max. 1755 microg g(-1) in S. maritima) clearly points to the dominant role of belowground biomass in the cycling of anthropogenic Pb. The fraction of anthropogenic Pb in belowground biomass was estimated based on the signature of anthropogenic Pb components in sediments ((206)Pb/(207)Pb=1.154). Since no differences exist between Pb signature in roots and upper sediments, the background and anthropogenic levels of Pb in roots were estimated. Interestingly, both background and anthropogenic Pb in roots exhibited a maximum at the same depth, although the proportion of anthropogenic Pb was relatively constant with depth (83+/-4% for S. fruticosa and 74+/-8% for S. maritima). PMID:17320933

Caetano, Miguel; Fonseca, Nuno; Cesário Carlos Vale, Rute

2007-02-23

336

Effect of root metabolism on the post-depositional mobilization of mercury in salt marsh soils  

SciTech Connect

Salt marsh soils are an efficient sink for trace metals associated with particulate material in tidal waters and have been proposed as monitors for trace metal contamination in coastal areas, on the basis that vertical profiles provide a record of loading rates. However, the complex nature of the biogeochemical processes occurring in these soils, may prevent this use, since post-depositional mobilization of some trace metals may occur, resulting in their release to pore water, vertical movement through the soil column and exchange with overlying waters. This paper presents and compares the vertical profiles of mercury in soil cores taken under a Spartina altermilflora marsh and in adjacent mod flats without plant cover to characterize the role played by this plant on the post-depositional movement of mercury through the soil and on the possibility of using such profiles as indicators of mercury loading rates in coastal areas. 19 refs., 1 fig., 1 tab.

Marins, R.V. [Fluminense Federal Univ., Niteroi (Brazil)]|[Mineral Technology Center, Rio de Janeiro (Brazil); Lacerda, L.D. [Fluminense Federal Univ., Niteroi (Brazil); Goncalves, G.O.; Paiva, E.C. de [Mineral Technology Center, Rio de Janeiro (Brazil)

1997-05-01

337

Multitemporal spectroradiometry-guided object-oriented classification of salt marsh vegetation  

NASA Astrophysics Data System (ADS)

This study addresses the use of multitemporal field spectral data, satellite imagery, and LiDAR top of canopy data to classify and map common salt marsh plant communities. Visible to near-infrared (VNIR) reflectance spectra were measured in the field to assess the phenological variability of the dominant species - Spartina patens, Phragmites australis and Typha spp. The field spectra and single date LiDAR canopy height data were used to define an objectoriented classification methodology for the plant communities in multitemporal QuickBird imagery. The classification was validated using an extensive field inventory of marsh species. Overall classification accuracies were 97% for Phragmites, 63% for Typha spp. and 80% for S. patens meadows. Using a fuzzy assessment analysis, these accuracies were 97%, 76%, and 92%, respectively, for the three major species.

Civco, Daniel L.; Gilmore, Martha S.; Wilson, Emily H.; Barrett, Nels; Prisloe, Sandy; Hurd, James D.; Chadwick, Cary

2008-10-01

338

Alteration of a salt marsh bacterial community by fertilization with sewage sludge  

SciTech Connect

The effects of long-term fertilization with sewage sludge on the aerobic, chemoheterotrophic portion of a salt marsh bacterial community were examined. The study site in the Great Sippewissett Marsh, Cap Cod, Mass., consisted of experimental plots that were treated with different amounts of commercial sewage sludge fertilizer or with urea and phosphate. The number of CFUs, percentage of mercury- and cadmium-resistant bacteria, and percentage of antibiotic-resistant bacteria were all increased in the sludge-fertilized plots. Preliminary taxonomic characterization showed fertilization markedly altered the taxonomic distribution and reduced diversity within both the total heterotrophic and the mercury-resistant communities. In control plots, the total heterotrophic community was fairly evenly distributed among taxa and the mercury-resistant community was dominated by Pseudomonas spp. In sludge-fertilized plots, both the total and mercury-resistant communities were dominated by a single Cytophaga sp.

Hamlett, N.V.

1986-10-01

339

Alteration of a Salt Marsh Bacterial Community by Fertilization with Sewage Sludge  

PubMed Central

The effects of long-term fertilization with sewage sludge on the aerobic, chemoheterotrophic portion of a salt marsh bacterial community were examined. The study site in the Great Sippewissett Marsh, Cape Cod, Mass., consisted of experimental plots that were treated with different amounts of commercial sewage sludge fertilizer or with urea and phosphate. The number of CFUs, percentage of mercury- and cadmium-resistant bacteria, and percentage of antibiotic-resistant bacteria were all increased in the sludge-fertilized plots. Preliminary taxonomic characterization showed that sludge fertilization markedly altered the taxonomic distribution and reduced diversity within both the total heterotrophic and the mercury-resistant communities. In control plots, the total heterotrophic community was fairly evenly distributed among taxa and the mercury-resistant community was dominated by Pseudomonas spp. In sludge-fertilized plots, both the total and mercury-resistant communities were dominated by a single Cytophaga sp.

Hamlett, Nancy V.

1986-01-01

340

Characterising the distribution and morphology of creeks and pans on salt marshes in England and Wales using Google Earth  

NASA Astrophysics Data System (ADS)

By using Google Earth images and simple morphometric analyses, pan and creek characteristics of salt marshes across England and Wales have been mapped and related to key environmental variables, including tidal range, sea level change, coastal configuration, sediment type and erosion state. Pan density was found to be higher on the west coast or where there is a moderate tidal range and low sea level change. Pan density is also higher on back barrier and drowned valley marshes and when creek density is low. Maximum pan size is partly controlled by pan density. Creek density and sinuosity showed great variability between areas with marshes in the south having a higher creek density. Creek density is related to tidal prism and marshes undergoing high rates of sea level change usually have higher creek densities. Marshes with an upstream configuration (embayment, drowned valley and back barrier) have lower creek densities due to a lower tidal prism. Sediment type also plays a role with lower creek densities found on coarser sediment types. Creek sinuosity seems to be largely controlled by tidal range with higher sinuosities on meso- or macro-tidal marshes. This large-scale, Google Earth-based, analysis of the distribution and likely environmental controls on salt marsh morphometry illustrates the utility of Digital Globes as sources of freely-available, high resolution imagery for geomorphological research.

Goudie, Alice

2013-09-01

341

The Life Cycle of Entzia, an Agglutinated Foraminifer from the Salt Marshes in Transylvania  

NASA Astrophysics Data System (ADS)

The small salt marshes associated with Miocene salt domes in Transylvania are host to a variety of marine organisms, including communities of halophytic plants as well as an agglutinated foraminifer that is normally found in coastal salt marshes worldwide. Originally described as the species Entzia tetrastoma by Daday (1884), the foraminifer is more widely known by the name Jadammina macrescens (Brady, 1870). Because the genus name Entzia has priority over Jadammina, the valid name of this taxon is Entzia macrescens (Brady, 1870). In 2007, we discovered a living population of Entzia inhabiting a small salt marsh just outside the town of Turda in central Transylvania, only a kilometer from the famous Maria Theresa Salt Mine. This is the first discovery of a living population of Entzia in Transylvania since the species was originally described in 1884. To determine whether or not the specimens we found represent a breeding population, samples were collected from the marsh on a monthly basis over the span of a year. This species can be found among the roots of the halophytic plants, in the uppermost one or two centimeters of the mud. Sediment samples were preserved in Vodka with Rose Bengal to distinguish living and dead specimens, and examined quantitatively. To document the life cycle of the species the following metrics were carried out: test size, abundance, number of chambers, ratio between live and dead specimens, and the diameter of the proloculus. An increase in the mean diameter of specimens was found from October to December. However the mean diameter decreased again in January, which suggests that asexual reproduction had apparently taken place. Small specimens again appeared in March, when sexual reproduction is presumed to have taken place. The median proloculus diameter was smallest in April and May, but the monthly changes in mean proloculus size within the population over the span of a year are not significant. However, specimens with largest proloculus diameters (up to 50 microns) are found in winter, and specimens with smallest proloculi (11 microns) are found in spring. In this respect, the life cycle of Entzia macrescens resembles that of the well-known invasive species Trochammina hadai. We are taking measures to preserve the site containing the living Entzia population, as the area is located opposite a public swimming pool and is endangered by human activity.

Kaminski, Michael; Telespan, Andreea; Balc, Ramona; Filipescu, Sorin; Varga, Ildiko; Görög, Agnes

2013-04-01

342

Interpreting Sea Level Rise and Rates of Vertical Marsh Accretion in a Southern New England Tidal Salt Marsh  

Microsoft Academic Search

An investigation of marsh accretion rates on a New England type high marsh (Barn Island Wildlife Management Area, Stonington, Connecticut) reveals that this system is sensitive to changes in sea level and storm activity and the peat can accurately record rates of relative submergence as determined by tide gauge records over intervals of 2–5 decades. The results also suggest that

R. A. Orson; R. S. Warren; W. A. Niering

1998-01-01

343

Assessment of Prey Availability for Diamondback Terrapins in a Connecticut Salt Marsh  

Microsoft Academic Search

Wheeler Marsh in Milford, Connecticut provides habitat for diamondback terrapins (Malaclemys terrapin), a unique estuarine turtle. To assess potential prey availability, the distribution and abundances of marsh snails (Melampus bidentatus), mud snails (Ilyanassa obsoleta), marsh mussels (Geukensia demissa), and fiddler crabs (Uca spp.) were studied in several sub- habitats (marsh surface, marsh edge, creek bank, and mudflats) of five tidal

Diana M. Whitelaw; Roman N. Zajac

2002-01-01

344

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

PubMed Central

Diversity and abundance of ammonia-oxidizing Betaproteobacteria (?-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 ?-AOB amoA richness at SAT and SP, but AOA and ?-AOB richness were similar at SAS. ?-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 ?-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 ?-AOB varied over 2 orders of magnitude among sites and sampling dates. Nevertheless, abundances of AOA and ?-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 ?-??? 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.

Moin, Nicole S.; Nelson, Katelyn A.; Bush, Alexander; Bernhard, Anne E.

2009-01-01

345

Suspended sediment deposition and trapping efficiency in a Delaware salt marsh  

NASA Astrophysics Data System (ADS)

This study examined sediment deposition and retention in a section of salt marsh in the St. Jones River estuary in Delaware. Sediment traps, siphon samplers, a LISST particle sizer, and four water level sensors were deployed in a 100 m by 200 m grid over the course of a spring tide in June 2007. The objective was to determine the relative influences of suspended sediment concentration, settling velocity, tidal hydroperiod, and vegetation density on sediment deposition and trapping efficiency within a small section of marsh. Hydroperiod is not a major contributor to sediment deposition in the study plot. Spatial patterns in depositional processes on tidal timescales are instead primarily controlled by overmarsh SSC, settling velocity, and distance from the tidal channel. Trapping efficiency, or the ratio of measured deposition and the amount of sediment available for deposition, decreased with distance away from the tidal channel, indicating that less of the available suspended sediment was deposited in the marsh interior. The suspended particles were flocculated, but floc sizes decreased with distance away from the tidal channel.

Moskalski, Susanne M.; Sommerfield, Christopher K.

2012-02-01

346

Seasonal Changes in Reflectance and Standing Crop Biomass in Three Salt Marsh Communities 1  

PubMed Central

Reflectance of red (656-705 nm) and infrared (776-826 nm) solar radiation and standing crop biomass were measured in three salt marsh communities at intervals of approximately 2 weeks between February and August 1974. Red reflectance declined at the onset of greening in each community and was correlated with standing crop of green biomass. Infrared reflectance increased substantially in the shrub community but less in the grass and sedge communities. The inverse of red reflectance was found to be a reliable predictor of green biomass in sedge and grass communities, but not in a shrub community.

Drake, Bert G.

1976-01-01

347

Draft Genome Sequence of Bacillus sp. Strain NSP2.1, a Nonhalophilic Bacterium Isolated from the Salt Marsh of the Great Rann of Kutch, India.  

PubMed

The 5.52-Mbp draft genome sequence of Bacillus sp. strain NSP2.1, a nonhalophilic bacterium isolated from the salt marsh of the Great Rann of Kutch, India, is reported here. An analysis of the genome of this organism will facilitate the understanding of its survival in the salt marsh. PMID:24158559

Dey, Rinku; Pal, Kamal Krishna; Sherathia, Dharmesh; Dalsania, Trupti; Savsani, Kinjal; Patel, Ilaxi; Sukhadiya, Bhoomika; Mandaliya, Mona; Thomas, Manesh; Ghorai, Sucheta; Vanpariya, Sejal; Rupapara, Rupal; Rawal, Priya; Saxena, Anil Kumar

2013-10-24

348

Positive interactions between cordgrass, Spartina alterniflora, and the brown alga, Ascophyllum nodosum ecad scorpioides, in a mid-Atlantic coast salt marsh  

Microsoft Academic Search

Interactions between salt marsh cordgrass, Spartina alterniflora, and the brown alga, Ascophyllum nodosum ecad scorpioides, were examined by determining effects of experimental removal of each species. Three sites were located in areas where A. nodosum formed a dense understory mat in the tall S. alterniflora zone of the Flax Pond salt marsh on Long Island, New York, USA. Removal of

Valrie A Gerard

1999-01-01

349

Spectroscopic properties of sedimentary humic acids from a salt marsh (Ria de Aveiro, Portugal): comparison of sediments colonized by Halimione portulacoides (L.) Aellen and non-vegetated sediments  

Microsoft Academic Search

The influence of the colonization of salt marsh sediments with Halimione portulacoides, on the composition of the sedimentary humic acids was evaluated. For this purpose, cores of colonized and non-colonized sediments from a salt marsh in Ria de Aveiro (Portugal) were collected, and the humic acids of different layers were extracted and characterized by Fourier transform infrared, synchronous molecular fluorescence

Ana Mendonça; Armando C. Duarte; Eduarda B. H. Santos

2004-01-01

350

Draft Genome Sequence of Bacillus sp. Strain NSP2.1, a Nonhalophilic Bacterium Isolated from the Salt Marsh of the Great Rann of Kutch, India  

PubMed Central

The 5.52-Mbp draft genome sequence of Bacillus sp. strain NSP2.1, a nonhalophilic bacterium isolated from the salt marsh of the Great Rann of Kutch, India, is reported here. An analysis of the genome of this organism will facilitate the understanding of its survival in the salt marsh.

Pal, Kamal Krishna; Sherathia, Dharmesh; Dalsania, Trupti; Savsani, Kinjal; Patel, Ilaxi; Sukhadiya, Bhoomika; Mandaliya, Mona; Thomas, Manesh; Ghorai, Sucheta; Vanpariya, Sejal; Rupapara, Rupal; Rawal, Priya; Saxena, Anil Kumar

2013-01-01

351

Physical Stress, Not Biotic Interactions, Preclude an Invasive Grass from Establishing in Forb-Dominated Salt Marshes  

PubMed Central

Background Biological invasions have become the focus of considerable concern and ecological research, yet the relative importance of abiotic and biotic factors in controlling the invasibility of habitats to exotic species is not well understood. Spartina species are highly invasive plants in coastal wetlands; however, studies on the factors that control the success or failure of Spartina invasions across multiple habitat types are rare and inconclusive. Methodology and Principal Findings We examined the roles of physical stress and plant interactions in mediating the establishment of the smooth cordgrass, Spartina alterniflora, in a variety of coastal habitats in northern China. Field transplant experiments showed that cordgrass can invade mudflats and low estuarine marshes with low salinity and frequent flooding, but cannot survive in salt marshes and high estuarine marshes with hypersaline soils and infrequent flooding. The dominant native plant Suaeda salsa had neither competitive nor facilitative effects on cordgrass. A common garden experiment revealed that cordgrass performed significantly better when flooded every other day than when flooded weekly. These results suggest that physical stress rather than plant interactions limits cordgrass invasions in northern China. Conclusions and Significance We conclude that Spartina invasions are likely to be constrained to tidal flats and low estuarine marshes in the Yellow River Delta. Due to harsh physical conditions, salt marshes and high estuarine marshes are unlikely to be invaded. These findings have implications for understanding Spartina invasions in northern China and on other coasts with similar biotic and abiotic environments.

He, Qiang; Cui, Baoshan; An, Yuan

2012-01-01

352

Comparison of Bulk and Compound-Specific Carbon Isotope Analyses and Determination of Carbon Sources to Salt Marsh Sediments Using n-Alkane Distributions (Maine, USA)  

NASA Astrophysics Data System (ADS)

Sources of sedimentary organic matter to a Morse River, Maine (USA) salt marsh over the last 3390+/-60 RCYBP are determined using distribution patterns of n-alkanes as well as bulk and compound-specific carbon isotopic analysis. Marsh foraminiferal counts indicate the ubiquitous presence of zone 1B deposits, suggesting that the deposits were laid down ~0.2 to 0.5m above mean high water. Distributions of n-alkanes show a primary contribution from higher plants, confirmed by an average ACL value of 27.5 for the core sediments and CPI values above 3. Many sample depths have a maximum abundance at the C25 alkane. Ten low marsh, high marsh, and higher-high marsh plant species common to Maine salt marshes were sampled, including Spartina alterniflora, Spartina patens, Juncus gerardi and Solidago sempervirens. The ACL value for the average of the 10 marsh species is 29.1. Salicornia europa, usually not considered to be a dominant species in Maine marshes, has a similar n-alkane distribution to many of the salt marsh sediments, suggesting that it is an important source to the biomass of the marsh through time. Bacterial degradation or algal inputs to the marsh sediments appear to be minor. Compound specific carbon isotopic analyses of the C27 alkanes are, on average, 7.2ppt. depleted relative to bulk values, but the two records are strongly correlated (R2 = 0.87), suggesting that marsh plants are "swamping" the bulk carbon isotopic signal. The apparent abundance of a subordinate (though common) salt marsh plant species (Salicornia europa) within our core underscores the importance of using caution when applying mixing models of relatively few plant species to marsh sediments.

Tanner, B. R.; Uhle, M. E.; Kelley, J. T.; Mora, C. I.

2005-12-01

353

Dynamics of Rainfall-mobilized Suspended Particulate Organic Carbon in Salt Marsh Tidal Creeks  

NASA Astrophysics Data System (ADS)

Climate models have projected a trend of more frequent and more intense rainfall events in many coastal landscapes due to goble climate change. Rainfall kinetic energy and runoff from severe thunderstorms have the ability to do a substantial amount of work on intertidal landscapes. For instance, low tide rainfall events can produce a 2-3 order of magnitude increase in suspended sediment concentration in subtidal channels. Moreover, low tide rainfall affects the bulk composition of carbon and other nutrients in surface sediments and in the water column. We sampled rainfall-mobilized suspended sediment in two intertidal creeks in North Inlet (South Carolina) salt marsh, examined their elemental (carbon and nitrogen), isotopic (?13C and ?15N), CuO oxidation product (COP) compositions, Chlorophyll a content, and use upscaling methods, to analyze the biogeochemical composition of rainfall-entrained suspended particulate organic carbon (RSPOC) and quantify the flux of RSPOC between marsh platform and subtidal channel. The concentrations and compositions of RSPOC varied widely but were significantly different from no-rain samples and salt marsh surface sediment. COP parameters such as lignin contents are higher in RSPOC, indicating a preferential transportation of terrestrial materials. Acid/aldehyde ratios of vanillyl and syringyl phenols, cinnamyl/vanillyl ratios and syringyl/vanillyl ratios indicate that RSPOC is more degraded and from distinct terrigenous sources. Chla/TSS ratio indicates that rainfall-entrained sediment contains less biotic material. Preliminary results indicated that 7-12 tons/km2 of POC can be mobilized in a single rain event. Therefore, low tide rainfall-runoff processes likely detach and transport organic matter which is compositionally distinct from tidally-resuspended particulate matter. The RSPOC is more degraded, with more of a terrestrial contribution and a higher abundance of abiotic materials. The significant input of these specific materials alters the biogeochemical characteristics of the subtidal water column.

Chen, S.; Torres, R.; Goni, M. A.

2011-12-01

354

Dynamics of Bacterial and Fungal Communities on Decaying Salt Marsh Grass†  

PubMed Central

Both bacteria and fungi play critical roles in decomposition processes in many natural environments, yet only rarely have they been studied as an integrated microbial community. Here we describe the bacterial and fungal assemblages associated with two decomposition stages of Spartina alterniflora detritus in a productive southeastern U.S. salt marsh. 16S rRNA genes and 18S-to-28S internal transcribed spacer (ITS) regions were used to target the bacterial and ascomycete fungal communities, respectively, based on DNA sequence analysis of isolates and environmental clones and by using community fingerprinting based on terminal restriction fragment length polymorphism (T-RFLP) analysis. Seven major bacterial taxa (six affiliated with the ?-Proteobacteria and one with the Cytophagales) and four major fungal taxa were identified over five sample dates spanning 13 months. Fungal terminal restriction fragments (T-RFs) were informative at the species level; however, bacterial T-RFs frequently comprised a number of related genera. Amplicon abundances indicated that the salt marsh saprophyte communities have little-to-moderate variability spatially or with decomposition stage, but considerable variability temporally. However, the temporal variability could not be readily explained by either successional shifts or simple relationships with environmental factors. Significant correlations in abundance (both positive and negative) were found among dominant fungal and bacterial taxa that possibly indicate ecological interactions between decomposer organisms. Most associations involved one of four microbial taxa: two groups of bacteria affiliated with the ?-Proteobacteria and two ascomycete fungi (Phaeosphaeria spartinicola and environmental isolate “4clt”).

Buchan, Alison; Newell, Steven Y.; Butler, Melissa; Biers, Erin J.; Hollibaugh , James T.; Moran, Mary Ann

2003-01-01

355

Salt marsh sediment diversity: a test of the variability of the rare biosphere among environmental replicates  

PubMed Central

Much of the phylogenetic diversity in microbial systems arises from rare taxa that comprise the long tail of taxon rank distribution curves. This vast diversity presents a challenge to testing hypotheses about the effects of perturbations on microbial community composition because variability of rare taxa among environmental replicates may be sufficiently large that it would require a prohibitive degree of sequencing to discern differences between samples. In this study we used pyrosequencing of 16S rRNA tags to examine the diversity and within-site variability of salt marsh sediment bacteria. Our goal was to determine whether pyrosequencing could produce similar patterns in community composition among replicate environmental samples from the same location. We hypothesized that repeated sampling from the same location would produce different snapshots of the rare community due to incomplete sequencing of the taxonomically rich rare biosphere. We demonstrate that the salt marsh sediments we sampled contain a remarkably diverse array of bacterial taxa and, in contrast to our hypothesis, repeated sampling from within the same site produces reliably similar patterns in bacterial community composition, even among rare organisms. These results demonstrate that deep sequencing of 16s tags is well suited to distinguish site-specific similarities and differences among rare taxa and is a valuable tool for hypothesis testing in microbial ecology.

Bowen, Jennifer L; Morrison, Hilary G; Hobbie, John E; Sogin, Mitchell L

2012-01-01

356

The Protective Role of Coastal Marshes: A Systematic Review and Meta-analysis  

PubMed Central

Background Salt marshes lie between many human communities and the coast and have been presumed to protect these communities from coastal hazards by providing important ecosystem services. However, previous characterizations of these ecosystem services have typically been based on a small number of historical studies, and the consistency and extent to which marshes provide these services has not been investigated. Here, we review the current evidence for the specific processes of wave attenuation, shoreline stabilization and floodwater attenuation to determine if and under what conditions salt marshes offer these coastal protection services. Methodology/Principal Findings We conducted a thorough search and synthesis of the literature with reference to these processes. Seventy-five publications met our selection criteria, and we conducted meta-analyses for publications with sufficient data available for quantitative analysis. We found that combined across all studies (n?=?7), salt marsh vegetation had a significant positive effect on wave attenuation as measured by reductions in wave height per unit distance across marsh vegetation. Salt marsh vegetation also had a significant positive effect on shoreline stabilization as measured by accretion, lateral erosion reduction, and marsh surface elevation change (n?=?30). Salt marsh characteristics that were positively correlated to both wave attenuation and shoreline stabilization were vegetation density, biomass production, and marsh size. Although we could not find studies quantitatively evaluating floodwater attenuation within salt marshes, there are several studies noting the negative effects of wetland alteration on water quantity regulation within coastal areas. Conclusions/Significance Our results show that salt marshes have value for coastal hazard mitigation and climate change adaptation. Because we do not yet fully understand the magnitude of this value, we propose that decision makers employ natural systems to maximize the benefits and ecosystem services provided by salt marshes and exercise caution when making decisions that erode these services.

Shepard, Christine C.; Crain, Caitlin M.; Beck, Michael W.

2011-01-01

357

Tidal salt marsh sediment in California, USA. Part 1: Occurrence and sources of organic contaminants  

Microsoft Academic Search

Surface sediment samples (0–5cm) from five tidal marshes along the coast of California, USA were analyzed for organic pollutants to investigate their relationship to land use, current distribution within marshes, and possible sources. Among the study areas, Stege Marsh, located in San Francisco Bay, was the most contaminated. Compared to San Francisco Bay, Stege Marsh had much higher levels of

Hyun-Min Hwang; Peter G. Green; Thomas M. Young

2006-01-01

358

Elemental Status in Sediment and American Oyster Collected from Savannah Marsh\\/Estuarine Ecosystem: A Preliminary Assessment  

Microsoft Academic Search

Sediment and American oyster (Crassostrea virginica) collected from nine selected marsh\\/estuarine ecosystems in Savannah, Georgia were analyzed for elements such as Al, As,\\u000a B, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Si, and Zn. Sediments were extracted by ammonium acetate (NH4OAc), Mehlich-3 (M-3), and water procedures, whereas an acid digestion procedure was adopted for oyster tissue. Concentrations\\u000a of

Kenneth S. Sajwan; Kurunthachalam Senthil Kumar; Sivapatham Paramasivam; Sanya S. Compton; Joseph P. Richardson

2008-01-01

359

Aquatic Insects of New York Salt Marsh Associated with Mosquito Larval Habitat and their Potential Utility as Bioindicators  

PubMed Central

The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonomic survey of salt marsh aquatic insects on Long Island, New York, USA and to evaluate their utility for non-target pesticide impacts and environmental biomonitoring. A total of 18 species from 11 families and five orders were collected repeatedly during the five month study period. Diptera was the most diverse order with nine species from four families, followed by Coleoptera with four species from two families, Heteroptera with three species from three families, then Odonata and the hexapod Collembola with one species each. Water boatmen, Trichocorixa verticalis Fieber (Heteroptera: Corixidae) and a shore fly, Ephydra subopaca Loew (Diptera: Ephydridae), were the two most commonly encountered species. An additional six species; Anurida maritima Guérin-Méneville (Collembola: Neanuridae), Mesovelia mulsanti White (Heteroptera: Mesovelidae), Enochrus hamiltoni Horn (Coleoptera: Hydrophilidae), Tropisternus quadristriatus Horn (Coleoptera: Hydrophilidae), Dasyhelea pseudocincta Waugh and Wirth (Diptera: Ceratopogonidae), and Brachydeutera argentata Walker (Diptera: Ephydridae), were found regularly. Together with the less common Erythrodiplax berenice Drury (Odonata: Libellulidae), these nine species were identified as the most suitable candidates for pesticide and environmental impact monitoring due to abundance, position in the food chain, and extended seasonal occurrence. This study represents a first step towards developing an insectbased index of biological integrity for salt marsh health assessment.

Rochlin, Ilia; Dempsey, Mary E.; Iwanejko, Tom; Ninivaggi, Dominick V.

2011-01-01

360

Aquatic insects of New York salt marsh associated with mosquito larval habitat and their potential utility as bioindicators.  

PubMed

The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonomic survey of salt marsh aquatic insects on Long Island, New York, USA and to evaluate their utility for non-target pesticide impacts and environmental biomonitoring. A total of 18 species from 11 families and five orders were collected repeatedly during the five month study period. Diptera was the most diverse order with nine species from four families, followed by Coleoptera with four species from two families, Heteroptera with three species from three families, then Odonata and the hexapod Collembola with one species each. Water boatmen, Trichocorixa verticalis Fieber (Heteroptera: Corixidae) and a shore fly, Ephydra subopaca Loew (Diptera: Ephydridae), were the two most commonly encountered species. An additional six species; Anurida maritima Guérin-Méneville (Collembola: Neanuridae), Mesovelia mulsanti White (Heteroptera: Mesovelidae), Enochrus hamiltoni Horn (Coleoptera: Hydrophilidae), Tropisternus quadristriatus Horn (Coleoptera: Hydrophilidae), Dasyhelea pseudocincta Waugh and Wirth (Diptera: Ceratopogonidae), and Brachydeutera argentata Walker (Diptera: Ephydridae), were found regularly. Together with the less common Erythrodiplax berenice Drury (Odonata: Libellulidae), these nine species were identified as the most suitable candidates for pesticide and environmental impact monitoring due to abundance, position in the food chain, and extended seasonal occurrence. This study represents a first step towards developing an insect-based index of biological integrity for salt marsh health assessment. PMID:22957707

Rochlin, Ilia; Dempsey, Mary E; Iwanejko, Tom; Ninivaggi, Dominick V

2011-01-01

361

New England salt marsh recovery: opportunistic colonization of an invasive species and its non-consumptive effects.  

PubMed

Predator depletion on Cape Cod (USA) has released the herbivorous crab Sesarmareticulatum from predator control leading to the loss of cordgrass from salt marsh creek banks. After more than three decades of die-off, cordgrass is recovering at heavily damaged sites coincident with the invasion of green crabs (Carcinusmaenas) into intertidal Sesarma burrows. We hypothesized that Carcinus is dependent on Sesarma burrows for refuge from physical and biotic stress in the salt marsh intertidal and reduces Sesarma functional density and herbivory through consumptive and non-consumptive effects, mediated by both visual and olfactory cues. Our results reveal that in the intertidal zone of New England salt marshes, Carcinus are burrow dependent, Carcinus reduce Sesarma functional density and herbivory in die-off areas and Sesarma exhibit a generic avoidance response to large, predatory crustaceans. These results support recent suggestions that invasive Carcinus are playing a role in the recovery of New England salt marshes and assertions that invasive species can play positive roles outside of their native ranges. PMID:24009763

Coverdale, Tyler C; Axelman, Eric E; Brisson, Caitlin P; Young, Eric W; Altieri, Andrew H; Bertness, Mark D

2013-08-29

362

The response of salt marsh vegetation to tidal reduction caused by the Oosterschelde storm-surge barrier  

Microsoft Academic Search

In 1986 a sluice gate barrier was completed in the mouth of the Oosterschelde estuary. The barrier has been partially or completely closed during 1986 and the first months of 1987. Consequently the high tides were reduced to such a level that the salt marshes were scarcely flooded. Since April 1987 the barrier has been closed on average during two

Jan de Leeuw; Leo P. Apon; Peter M. J. Herman; W. De Munck; Wim G. Beeftink

1994-01-01

363

Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat complexity  

Microsoft Academic Search

Studies of diet choice by omnivores have the potential to form conceptual links between studies of diet choice by herbivores, frugivores, detritivores, and predators. We examined diet choice in the omnivorous salt marsh crab Armases cinereum (=Sesarma cinereum (Grapsidae)) in a series of laboratory experiments. Armases is sexually dimorphic, with larger males having relatively larger claws than females. In a

Tracy L. Buck; Greg A. Breed; Steven C. Pennings; Margo E. Chase; Martin Zimmer; Thomas H. Carefoot

2003-01-01

364

RELATIONSHIPS OF NITROGEN LOADINGS, RESIDENTIAL DEVELOPMENT, AND PHYSICAL CHARACTERISTICS WITH PLANT STRUCTURE IN NEW ENGLAND SALT MARSHES  

EPA Science Inventory

We examined the vascular plant species richness and the extent, density, and height of Spartina species of ten Narragansett Bay, Rhode Island (United States) fringe salt marshes which had a wide range of residential land development N-loadings associated with their watersheds. Si...

365

LINKING ECOLOGICAL IMPACT TO METAL CONCENTRATIONS AND SPECIATION: A MICROCOSM EXPERIMENT USING A SALT MARSH MEIOFAUNAL COMMUNITY  

Microsoft Academic Search

Microcosm experiments addressed the impact of a mixture of Cu, Cr, Cd, Pb, and Hg at three concentrations after 36 h, 12 d, and 30 d on a meiofauna-dominated salt marsh community. In addition to analyzing effects on meiofaunal abundances, the study quantified the sediment metal concentrations of all five metals and pore-water concentrations, speciation, and ligand complexation of Cu.

Rod N. Millward; Kevin R. Carman; John W. Fleeger; Robert P. Gambrell; Rodney T. Powell; Mary-Anne M. Rouse

2001-01-01

366

New England Salt Marsh Recovery: Opportunistic Colonization of an Invasive Species and Its Non-Consumptive Effects  

PubMed Central

Predator depletion on Cape Cod (USA) has released the herbivorous crab Sesarmareticulatum from predator control leading to the loss of cordgrass from salt marsh creek banks. After more than three decades of die-off, cordgrass is recovering at heavily damaged sites coincident with the invasion of green crabs (Carcinusmaenas) into intertidal Sesarma burrows. We hypothesized that Carcinus is dependent on Sesarma burrows for refuge from physical and biotic stress in the salt marsh intertidal and reduces Sesarma functional density and herbivory through consumptive and non-consumptive effects, mediated by both visual and olfactory cues. Our results reveal that in the intertidal zone of New England salt marshes, Carcinus are burrow dependent, Carcinus reduce Sesarma functional density and herbivory in die-off areas and Sesarma exhibit a generic avoidance response to large, predatory crustaceans. These results support recent suggestions that invasive Carcinus are playing a role in the recovery of New England salt marshes and assertions that invasive species can play positive roles outside of their native ranges.

Coverdale, Tyler C.; Axelman, Eric E.; Brisson, Caitlin P.; Young, Eric W.; Altieri, Andrew H.; Bertness, Mark D.

2013-01-01

367

The dose-response relationship between No. 2 fuel oil and the growth of the salt marsh grass, Spartina alterniflora  

Microsoft Academic Search

The effect of No. 2 fuel oil on the biomass production of the salt marsh plant, Spartina alterniflora, was studied in a greenhouse dose-response experiment. S. alterniflora were transplanted into soil with 10 dosage levels of No. 2 fuel oil ranging from 0 to 456 mgg?1 dry soil. Three months after transplantation, values for plant biomass, stem density, and shoot

Qianxin Lin; Irving A Mendelssohn; Makram T Suidan; Kenneth Lee; Albert D Venosa

2002-01-01

368

Oligochaeta in Spartina stems: the microdistribution of Enchytraeidae and Tubificidae in a salt marsh, Sapelo Island, USA  

Microsoft Academic Search

The distribution and abundance of Enchytraeidae and Tubificidae in and around Spartina alterniflora plants in a tidal salt marsh on Sapelo Island, Georgia, USA were studied using two different sampling techniques: wet funnel extraction and stem dissection. At least 80% of all worms inhabited leaf sheaths at the bases of S. alterniflora plants, and densities were low in sediment, root

Brenda Healy; Keith Walters

1994-01-01

369

Enhancement of natural radioactivity in soils and salt-marshes surrounding a non-nuclear industrial complex  

Microsoft Academic Search

The existence of a very high extension (about 1000 ha) of phosphogypsum piles, sited in the estuary formed by the mouths of the Tinto and Odiel rivers (SW Spain), produce a quite local, but unambiguous radioactive impact in the surrounding salt-marshes. In these piles the main by-product formed in the manufacture of phosphoric acid is stored. The radioactive impact is

J. P. Bolívar; R. García-Tenorio; M. García-León

1995-01-01

370

Variability of soil carbon sequestration capability and microbial activity of different types of salt marsh soils at Chongming Dongtan  

Microsoft Academic Search

Variations in the soil carbon sequestration capability of different types of salt marsh soils at Chongming Dongtan and its influencing factors were studied by analyzing the soil organic carbon (SOC) content, organic matter input and microbial activities. The results indicated that the total SOC content at Area A (southeast of Dongtan, sandy soil with Phragmites communis) was only 46.11% of

Yan-li Li; Lei Wang; Wen-quan Zhang; Shi-ping Zhang; Hong-li Wang; Xiao-hua Fu; Yi-quan Le

2010-01-01

371

Feasibility of using dredge spoil to generate a wildlife reserve and salt marsh in San Diego Bay, California  

Microsoft Academic Search

A multidisciplinary feasibility study involving extensive interaction with regulatory agencies and environmental groups has shown that the proposed use of about one million cubic yards of unpolluted dredged sediment from a small boat basin to build a 90 to 100 acre island-like wildlife reserve and associated salt marsh would be environmentally beneficial, compatible with existing local multiple land\\/water use, and

David D. Smith; Tomas E. Firee; Charles T. Mitchell; Malcolm L. Whitt

1975-01-01

372

Long-term effects of mercury in a salt marsh: Hysteresis in the distribution of vegetation following recovery from contamination  

Microsoft Academic Search

During four decades, the Ria de Aveiro was subjected to the loading of mercury from a chlor-alkali industry, resulting in the deposition of several tons of mercury in the sediments. The present study evaluates the impact of this disturbance and the recovery processes, temporally and spatially, by means of examining the richness of the species of salt marsh plants and

M. Válega; A. I. Lillebø; M. E. Pereira; A. C. Duarte; M. A. Pardal

2008-01-01

373

A simple empirical model of salt marsh plant spatial distributions with respect to a tidal channel network  

Microsoft Academic Search

Previous work has shown that the distribution of plant species in a salt marsh near Petaluma, CA, is strongly influenced by the location and size of tidal channels. We developed a simple mathematical model to measure the “channel influence” at each point as a cumulative function based on inverse squared distance to channel, length of potentially influential channel, and channel

Eric W. Sanderson; Theodore C. Foin; Susan L. Ustin

2001-01-01

374

Morphodynamics of Holocene salt marshes: a review sketch from the Atlantic and Southern North Sea coasts of Europe  

Microsoft Academic Search

Salt marshes, most now embanked, together with genetically related wetlands and high intertidal flats, make a major environmental contribution to the lowland coasts of Northwest Europe. They occur in many different contexts, but chiefly on open and barrier coasts and in estuaries and embayments, and range greatly in scale, from a modest total that measure hundreds of square kilometres in

J. R. L. Allen

2000-01-01

375

Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)  

EPA Science Inventory

CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

376

Population structure of the ribbed mussel Geukensia demissa in salt marshes in the southern Gulf of St. Lawrence, Canada  

NASA Astrophysics Data System (ADS)

The ribbed mussel, Geukensia demissa, is highly dependent on the cordgrass Spartina alterniflora for amelioration from environmental stress and substrate stabilization. Spartina alterniflora is a foundation species in marshes, and G. demissa is typically associated with cordgrass beds. Marshes in the southern Gulf of St. Lawrence are experiencing erosion and degradation, presumably as a result of increases in sea level, which increases salinity exposure and negatively impacts S. alterniflora. The population structure of the ribbed mussel, Geukensia demissa, was studied at nine sites in six estuaries in the southern Gulf of St. Lawrence in Nova Scotia, Canada, where marsh degradation is occurring. Mussel length was used as a proxy for age of G. demissa in three salt marsh zones characterized by density and elevation of Spartina alterniflora: (1) a lower zone in which the S. alterniflora was dead, but where the basal mat was coherent, (2) a zone of living, but low density S. alterniflora at the margin of the living marsh, and (3) a zone of dense S. alterniflora one to three meters back from the edge. Mussel length was significantly different across the three zones in seven of the nine sites. Mean length decreased as elevation increased, and small mussels (i.e., 1-3 cm) were absent at seven sites. The smallest mussels occurred in the dense S. alterniflora zone, higher in the marsh. Mussel length in the two western sites did not differ between zones, and small mussels (i.e., 1-3 cm) were present, but rare. The absence of small mussels in seven of the nine sites, and the size frequency distribution at remaining sites, suggests a lack of recent recruitment and a long-term threat to the survival of G. demissa. Salt marsh degradation and the death of S. alterniflora have negatively impacted G. demissa recruitment, and population decline is evident.

Watt, Cortney; Garbary, David J.; Longtin, Caroline

2011-09-01

377

Effects of soil PH, redox potential, and elevation on survival of Spartina patens planted at a west Central Florida salt marsh restoration site  

Microsoft Academic Search

PlantingSpartina patens (Salt Meadow Cord Grass) is an integral part of restoring salt marshes along Tampa Bay, Florida, USA. Of the salt marsh species\\u000a that are planted,S. patens often has the lowest survivorship. State managers have hypothesized that this low survivorship is related to transplant shock\\u000a and to acidic soil conditions commonly found under dense stands ofCasuarina sp. (Australian Pine),

Christopher J. Anastasiou; J. Renée Brooks

2003-01-01

378

Ecological Relationships between Meloidogyne spartinae and Salt Marsh Grasses in Connecticut.  

PubMed

Healthy specimens of selected grasses were collected from salt marshes and grown in the greenhouse. Plants were inoculated with Meloidogyne spartinae to determine the host range of this nematode. After 12 weeks, Spartina alterniflora plants formed root galls in response to infection and increased M. spartinae populations. Spartina patens, Spartina cynosuroides, Juncus gerardii and Distichlis spicata were non-hosts. In order to determine the natural distribution of M. spartinae in dieback areas, S. alterniflora plants were sampled from transects adjacent to dieback areas in Madison, CT, at low tide. Plants were sampled at the top or the creek and at 1-m intervals to the lowest area of plant growth at the low tide water's edge. Five samples were taken over an elevation drop of 90 cm. Two transects were taken each day on 21 June and 5 July 2007, and one transect was taken on 31 October 2007. Meloidogyne spartinae galls per gram root were higher at the higher elevations. In late June and early July 2007, M. spartinae developed more quickly in the higher elevations, perhaps because peat and sediments were drier and warmer away from low tide water levels. The effects of M. spartinae on S. alterniflora and the role of the nematode in marsh decline and dieback in the northeast United States remain to be determined. PMID:19440262

Lamondia, J A; Elmer, W H

2008-09-01

379

Nutrient retention in plant biomass and sediments from the salt marsh in Hangzhou Bay estuary, China.  

PubMed

Nutrient load into the ocean can be retained during the process of plant uptake and sedimentation in marshes along the bay zone. Seasonal variations of biomass and nutrient concentration in three dominated plant assemblages and associated sediments were monitored in this study area to determine effects of salt marsh on nutrient retention. Results showed that plant aboveground biomass displayed a unimodal curve with nutrient concentration generally decreased from spring to winter. Belowground biomass was relatively low during the rapid growth period with nutrient concentration tending to decrease and then increase during this period. Plant total nitrogen (TN) pools are higher than total phosphorus (TP) pools, and both pools showed significant seasonal variations. Water purification coefficients (WPC) of nutrients by plant assimilation were 34.4/17.3, 19.3/24.0, and 5.14/6.04 t/(m(2) year) (TN/TP) for Phragmites australis, Spartina alterniflora, and Scirpus mariqueter, respectively. Overall, these results suggest that higher annual plant biomass and nutrient assimilation contribute to greater nutrient retention capacity and accumulation in sediments, thereby enabling reduced eutrophication in transitional waters. PMID:23589271

Shao, Xuexin; Wu, Ming; Gu, Binhe; Chen, Yinxu; Liang, Xinqiang

2013-04-16

380

Role of different salt marsh plants on metal retention in an urban estuary (Lima estuary, NW Portugal)  

NASA Astrophysics Data System (ADS)

The aim of the present work was to understand the role different salt marsh plants on metal distribution and retention in the Lima River estuary (NW Portugal), which to our knowledge have not been ascertained in this area yet. The knowledge of these differences is an important requirement for the development of appropriate management strategies, and is poorly described for Eurosiberian estuaries, like the one selected. In addition it is important to understand the difference among introduced and native salt marsh plants. In this work, metal levels (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were surveyed (by atomic absorption spectrometry) in sediments from sites vegetated with Juncus maritimus, Spartina patens, Phragmites australis and Triglochin striata (rhizo-sediments), in non-vegetated sediments and in the different tissues of the plants (roots, rhizomes and aerial shoots). In general, rhizo-sediments had higher metal concentrations than non-vegetated sediments, a feature that seems common to sediments colonized by salt marsh plants of different estuarine areas. All plants concentrated metals, at least Cd, Cu and Zn (and Pb for T. striata) in their belowground structures ([ M] belowground tissues/[ M] non-vegetated sediment > 1). However, when considered per unit of salt marsh area, the different selected plants played a different role on sediment metal distribution and retention. Triglochin striata retained a significant metal burden in it belowground structures (root plus rhizomes) acting like a possible phyto-stabilizer, whereas P. australis had an higher metal burden in aboveground tissues acting as a possible phyto-extractor. As for J. maritimus and S. patens, metal burden distribution between above and belowground structures depended on the metal, with J. maritimus retaining, for instance, much more Cd and Cu in the aboveground than in the belowground structures. Therefore, the presence of invasive and exotic plants in some areas of the salt marsh may considerably affect metal distribution and retention in the estuarine region.

Almeida, C. M. R.; Mucha, Ana P.; Teresa Vasconcelos, M.

2011-01-01

381

Greenhouse Gas and Mercury Emissions from a Salt Marsh on the Bay of Fundy  

NASA Astrophysics Data System (ADS)

The Bay of Fundy, primarily situated between the provinces of New Brunswick and Nova Scotia in Canada is known have tides among the highest in the world, where tidal amplitudes have reached 17 m, and regularly exceed 12-13m. The reason for these extremely high tides has been attributed to basin morphology and tidal resonance. Along the margin of the Bay of Fundy, salt marshes are exposed to these high tidal ranges. These salt marshes have unknown greenhouse gas (CO2, CH4 specifically) and mercury trace gas budgets. Tides here exert significant pressure on salt marsh sediments, to the point where gases are visibly seen escaping around the waters edge. This pressure-driven gas transport phenomena is markedly different than most greenhouse gas releases from other sediments, which occurs primarily by diffusion. Our study site in Kingsport, NS, Canada also provides a unique opportunity to examine pressure-driven emissions using differential pressure measurements. This work is significant in determining the role of salt marshes in the carbon and mercury emission budgets in the maritime region, and their sensitivity to environmental forcings. For our study, mercury fluxes were measured using Teflon flux chamber technique with Tekran gaseous mercury analysis, while CO2 and CH4 fluxes were measured at 60 second intervals using a new technique called continuous timeseries-forced diffusion (CT-FD). A portable meteorological station was located on site, with soil temperature, solar radiation, soil O2, and soil-atmosphere differential pressure measurements logged continuously for 10 days and 19 tidal cycles. After the field deployment, the CO2 and CH4 instrumentation was moved to soil plots in mesocosm tidal-simulation benches to conduct experiments that would allow us to separate the difference between tidal forcings and thermally-driven microbial greenhouse gas production in sediments. In the field, differential pressure varied according to tidal cycles and was surprising in that rebound to atmospheric pressure rarely occurred. Instead, pressure gradients were sustained in the sediments during high (excess pressure) and low (pressure deficit) tides. While no compelling relationship appears evident between mercury, CO2, or CH4 flux and tidal height, ratios of flux to solar radiation suggest that tidal inundation and gas release does at least facilitate mercury release from sediments during peak flux times. Low gas diffusivity sediments (very fine, impermeable, compact) are potentially very important at these sites, potentially damping transport rates across the soil surface. Gas bubbles, which can be observed at the incoming waterline, may be preferentially emitted through more permeable sediment layers and subsurface sand channels rather than the surface. The Bay of Fundy setting provides a rather unique and challenging opportunity to study extreme examples of trace gas flux and gas transport dynamics.

O'Driscoll, N.; McArthur, G. S.; Risk, D. A.; Dalziel, J.; Beltrami, H.

2009-12-01

382

Prescribed fire and cutting as tools for reducing woody plant succession in a created salt marsh  

USGS Publications Warehouse

This paper reports on efforts to reduce woody successional growth by the native shrub Iva frutescens L. in a created salt marsh by using prescribed fire and cutting. Experimental treatments included a winter burn, cutting plants at ground level, and a combination burn-and-cut treatment, with replicate plots of each. Iva frutescens proved to be extremely hardy, with zero mortality following the cutting, burning, or combination treatment; similar levels of regrowth were observed for all treatments. Individual shrub response, however, was found to be related to initial plant size, ground water level and salinity, and two fire characteristics (total heating >60??C and total heat index >60??C). Fire severity, sediment nutrient concentrations, and other abiotic factors had no observable effects. ?? 2007 Springer Science+Business Media B.V.

Owens, A. B.; Proffitt, C. E.; Grace, J. B.

2007-01-01

383

Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities  

NASA Astrophysics Data System (ADS)

This paper reports changes in vegetation distribution and species cover in relation to soil factors and hydrology in a semiarid Mediterranean salt marsh adjacent to the Mar Menor saline lagoon. Species cover, soil salinity, and the groundwater level were monitored between 1991 and 1993 and between 2002 and 2004, and total organic carbon, total nitrogen, total phosphorus, nitrates, ammonium and exchangeable phosphorus were measured in the soils in both study periods. In addition, three soil profiles were described in August 1992 and August 2004. The results indicate an elevation of the water table throughout the 13-year period, which was attributable to water flowing from areas with intensive agriculture. Flooding increased and soil salinity dropped in the most saline sites and increased in the least saline ones. The morphology of the soil profiles reflected the increase in flooding periods, due to the appearance of a greyer matrix in the deeper horizons and a more diffuse pattern of Fe mottles. Following these environmental changes, Sarcocornia fruticosa, Phragmites australis and Juncus maritimus strongly expanded at the wettest sites, which led to the disappearance of the original zonation pattern. The cover of Limonium delicatulum, in turn, decreased with the increase in moisture but increased following the increase in salinity. Changes in soil nutrients were only very evident in the sandy soils of the beach, probably due to the influence of organic debris deposited on the shoreline by the storms and due to the strong increase in the colonisation of this habitat by perennial species. According to the results obtained, control measures are needed in order to preserve habitat diversity in this and other salt marshes of this area. Monitoring of the vegetation distribution could be a useful tool to identify environmental impacts, in order to implement remedial actions.

Álvarez-Rogel, J.; Jiménez-Cárceles, F. J.; Roca, M. J.; Ortiz, R.

2007-07-01

384

A regional assessment of salt marsh restoration and monitoring in the Gulf of Maine  

USGS Publications Warehouse

We compiled salt marsh monitoring datasets from 36 complete or imminent restoration projects in the Gulf of Maine to assess regional monitoring and restoration practices. Data were organized by functional indicators and restoration project types (culvert replacement, excavation works, or ditch plugging) then pooled to generate mean values for indicators before restoration, after restoration, and at reference sites. Monitoring data were checked against the regional standards of a voluntary protocol for the Gulf of Maine. Data inventories showed that vegetation and salinity indicators were most frequently collected (89 and 78% of sites, respectively), whereas nekton, bird, and hydrologic measures were collected at only about half of the sites. Reference conditions were monitored at 72% of sites. Indicators were analyzed to see if project sites were degraded relative to reference areas and to detect ecological responses to restoration activities. Results showed that compared to reference areas, prerestoration sites had smaller tidal ranges, reduced salinity levels, greater cover of brackish plants species, and lower cover of halophyte plants. Following restoration, physical factors rebounded rapidly with increased flood and salinity levels after about one year, especially for culvert projects. Biological responses were less definitive and occurred over longer time frames. Plant communities trended toward recovered halophytes and reduced brackish species at 3+ years following restoration. Nekton and avian indicators were indistinguishable among reference, impacted, and restored areas. The protocol was successful in demonstrating restoration response for the region, but results were limited by regional inconsistencies in field practices and relatively few multiyear datasets. To improve future assessment capabilities, we encourage greater adherence to the standard protocol throughout the Gulf of Maine salt marsh restoration community.

Konisky, R.A.; Burdick, D. M.; Dionne, M.; Neckles, H. A.

2006-01-01

385

New species of Fusarium associated with dieback of Spartina alterniflora in Atlantic salt marshes.  

PubMed

Sudden vegetation dieback (SVD) is the loss of smooth cordgrass (Spartina alterniflora) along intertidal creeks in salt marshes of the Atlantic and Gulf states. The underlying cause of SVD remains unclear, but earlier work suggested a contributing role for Fusarium spp. in Louisiana. This report investigated whether these or other Fusarium species were associated with S. alterniflora dieback in mid- to north-Atlantic states. Isolations from seven SVD sites yielded 192 isolates of Fusarium spp., with more than 75% isolated from aboveground tissue. Most isolates (88%) fell into two undescribed morphospecies (MS) distinguished from each other by macroconidial shape, phialide ontogeny and growth rates. Pathogenicity tests on wound-inoculated S. alterniflora stems and seedling roots revealed that isolates in MS1 were more virulent than those in MS2 but no single isolate caused plant mortality. No matches to known species of Fusarium were revealed by DNA sequence queries of translation elongation factor 1-? (tef1) sequences. A phylogenetic analysis of partial sequences of three genes, ?-tubulin (?-tub), calmodulin (cal) and tef1, was conducted on representative isolates from MS1 (n = 20) and MS2 (n = 18); it provided strong evidence that the MS1 isolates form a clade that represents a heretofore undescribed species, which we designate Fusarium palustre sp. nov. Isolates from the more variable MS2 clustered with the F. incarnatum-equiseti species complex as F. cf. incarnatum. Although a strong association exists between both species and declining S. alterniflora in SVD sites, neither appears to play a primary causal role in SVD. However, our findings suggest that F. palustre might play an important secondary role in the ecological disruption of the salt marshes. PMID:21471289

Elmer, Wade H; Marra, Robert E

2011-04-06

386

Assessment of phosphogypsum impact on the salt-marshes of the Tinto river (SW Spain): role of natural attenuation processes.  

PubMed

About 120 Mton of phosphogypsum from the fertiliser industry were stack-piled on the salt-marshes of the Tinto river (Spain). This paper investigates the capacity of salt-marshes to attenuate contamination due to downward leaching from phosphogypsum. Solids and pore-waters were characterized at different depths of the pile to reach the marsh-ground. In superficial zones, metals were highly mobile, and no reduced sulphur was found. However, pollutant concentration decreased in the pore-water in deeper oxygen-restricted zones. Metal removal occurred by precipitation of newly formed sulphides, being this process main responsible for the contamination attenuation. Pyrite-S was the main sulphide component (up to 2528 mg/kg) and occurred as framboids, leading to high degrees of pyritization (up to 97%). The sulphidization reaction is Fe-limited; however, excess of acid-volatile sulphide over other metals cause precipitation of other sulphides, mainly of Cu and As. This decrease in metal mobility significantly minimises the impact of phosphogypsums on the salt-marshes. PMID:21992931

Pérez-López, Rafael; Castillo, Julio; Sarmiento, Aguasanta M; Nieto, José M

2011-10-10

387

Selenium biotransformation by the salt marsh cordgrass Spartina alterniflora: Evidence for dimethylselenoniopropionate formation  

SciTech Connect

Phytoremediation of toxic inorganic selenium compounds by accumulation, assimilation, and volatilization is an ideal way to rid contaminated soils and sediments of these molecules. In this context, salt marsh cordgrass (Spartina alterniflora) was investigated for its potential to produce dimethylselenoniopropionate (DMSeP), which as the authors have shown can serve as a precursor for the enzymatic volatilization of the relatively nontoxic gas, dimethylselenide (DMSe). Plants grown in sand culture, under varying saline conditions amended with the environmentally toxic form of selenium (selenate) were analyzed for organoselenium compounds. DMSeP was positively identified in plant tissue and partially purified plant extracts by alkaline degradation to DMSe, [sup 1]H and [sup 77]Se NMR, and by enzymatic cleavage by DMSP lyase to DMSe (and acrylate). DMSeP levels were highest in plants grown in high salt (full-strength seawater) and high selenium. Preliminary evidence suggests that cordgrass may also produce Se-methyl selenomethionine, the putative precursor of DMSeP. This appears to be the first report for the biological assimilation of selenate into DMSeP by a plant species. These findings suggest a possible mechanism for the volatilization of selenium, as DMSe, analogous to that of dimethylsulfide (DMS) production by the salt tolerant cordgrass, Spartina alterniflora.

Ansede, J.H.; Pellechia, P.J.; Yoch, D.C. (Univ. of South Carolina, Columbia, SC (United States))

1999-06-15

388

EFFECTS OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND SALT MARSH  

EPA Science Inventory

Coastal marshes represent an important transitional zone between uplands and estuaries. One important function of marshes is to assimilate nutrient inputs from uplands, thus providing a buffer for anthropogenic nutrient loads. We examined the effects of nitrogen (N) and phosphoru...

389

VARYING LANDSCAPE STRUCTURE AND POTENTIAL DENITRIFICATION ACTIVITY AMONG SALT MARSHES ALONG AN ANTHROPOGENIC DISTURBANCE GRADIENT  

EPA Science Inventory

Marsh landscape structure and denitrification are proposed as indicators of key wetland services, providing animal habitat and water quality maintenance, respectively. We examined marsh landscape structure (i.e., plant species richness and extent of dominant plant species) and po...

390

The role of groundwater flow in controlling the spatial distribution of soil salinity and rooted macrophytes in a southeastern salt marsh, USA  

Microsoft Academic Search

Groundwater flow is an important factor in governing botanical zonation in the salt marsh at North Inlet, SC. Areas of the marsh adjacent to upland forest are characterized by upward flow of fresh groundwater. This inhibits the infiltration and evapoconcentration of saline tidal water and the development of a habitat for hypersaline-tolerant fugitive species such as Salicornia europaea. Areas of

Peter M. Thibodeau; Leonard Robert Gardner; Howard W. Reeves

1998-01-01

391

Sulfur, carbon, and nitrogen isotopes used to trace organic matter flow in the salt-marsh estuaries of Sapelo Island, Georgia  

Microsoft Academic Search

The stable isotopes of sulfur, nitrogen, and carbon were used to trace organic matter flow in salt marshes and cstuarinc waters at Sapelo Island, Georgia. Organic matter inputs from terrestrial sources as detrital input either from forests adjacent to the marshes or from rivers were not dctcctable by their isotopic signatures in estuarine consumers. The results suggest that there are

BRUCE J. PETERSON; ROBERT W. HOWARTH

1987-01-01

392

Seasonal changes in community composition and trophic structure of fish populations of five salt marshes along the Essex coastline, United Kingdom  

NASA Astrophysics Data System (ADS)

European intertidal salt marshes are important nursery sites for juvenile fish and crustaceans. Due to the increasing threat of habitat loss, the seasonal changes of salt marsh fish communities need to be understood in order to appreciate the ecological and economic importance of the saltmarsh habitat. This study was the first in Great Britain to investigate the seasonal changes of salt marsh fish communities and the variation in community structure between closely located marsh habitats. Between February 2007 and March 2008, five marshes on three estuaries of the Essex coastline were sampled using flume nets to block off intertidal creeks at high tide. Fourteen fish species were caught. The community overall was dominated by three species that made up 91.6% of the total catch: the common goby Pomatoschistus microps (46.2% of the total catch), juvenile herring Clupea harengus (24.3%), and juvenile and larval sea bass Dicentrarchus labrax (21.2%). Cluster analysis demonstrated clear seasonal patterns, with some community structures unique to specific marshes or estuaries. The marsh fish community shifts from a highly diverse community during spring, to a community dominated by D. labrax and P. microps in autumn, and low diversity during winter months. Gravimetric stomach content analysis of fish community identified three main trophic guilds; macroinvertivores, planktivores and omnivores. The macroinvertivore feeding guild contained D. labrax and P. microps, the two most frequently occurring species. This investigation demonstrates the importance of British salt marshes as nursery habitats for commercial fish species.

Green, Benjamin C.; Smith, David J.; Earley, Sarah E.; Hepburn, Leanne J.; Underwood, Graham J. C.

2009-11-01

393

Marsh vegetation patterns and soil phosphorus gradients in the Everglades ecosystem  

Microsoft Academic Search

In order to test the hypothesis that phosphorous enrichment is modifying Everglades marsh community composition, we sampled vegetation and soil phosphorus concentrations along four transects in areas representative of varying environmental conditions within the Everglades region. Each transect originated at or near a canal flow control structure and extended towards the center of the marsh because the canal flow structures

Robert F. Doren; Thomas V. Armentano; Louis D. Whiteaker; Ronald D. Jones

1997-01-01

394

Salt Marsh development studies at Waquoit Bay, Massachusetts: Influence of geomorphology on long-term plant community structure  

NASA Astrophysics Data System (ADS)

Stochastic events relating to beach formation and inlet dynamics have been the major factors influencing the development of the Waquoit Bay tidal marshes. This results from the physical structure of the Waquoit Bay system where tidal exchange is limited to one or two small inlets and is in contrast to marsh development in nearby Barnstable Marsh where direct unrestricted exchange with Cape Cod Bay has smoothed the effects of stochastic events on vegetation development. We contend that vegetation development in salt marshes where connections to adjacent waters are restricted will be dominated by abiotic factors (e.g. storms, sedimentation rates, etc.) while those marshes directly linked to open bodies of water and where alterations to hydrodynamic factors are gradual, autecological processes (e.g. interspecific competition) will dominate long-term plant community development. The results from the five marsh systems within the Waquoit Bay complex suggest that once a vegetation change occurs the new community tended to persist for long periods of time (100's 1000's years). Stability of the ‘new’ community appeared to depend upon the stability of the physical structure of the system and/or time between perturbations necessary to allow the slower autecological processes to have a discernable effect. In order for the plant community to persist as long as observed, the vegetation must also be exerting an influence on the processes of development. Increased production of roots and rhizomes and growth characteristics (density of culms) are some of the factors which help to maintain long-term species dominance. It is clear from this investigation that the structure of the plant community at any one point in time is dependent upon numerous factors including historical developmental influences. To properly assess changes to the present plant community or determine recent rates of accretion, historic developmental trends must be considered. The factors that have influenced the development of marsh in the past will be important in understanding and formulating predictive models in the future.

Orson, Richard A.; Howes, Brian L.

1992-11-01

395

Controls on spatial patterns of sediment deposition across a macro-tidal salt marsh surface over single tidal cycles  

NASA Astrophysics Data System (ADS)

A field study was conducted to determine the controls on spatial patterns of sediment deposition across a salt marsh surface in the Bay of Fundy. Approximately 670 surface-mounted sediment traps were deployed over 28 different tidal cycles in a variety of spatial configurations and environmental conditions. Spatial patterns of deposition were derived using spatial interpolation procedures in ArcView GIS 3.2. Suspended sediment concentration, flow characteristics and water depth were measured using co-located optical backscatterance sensors, electromagnetic current meters and a pressure transducer. Sediment deposition was a complex function of variables controlling the availability of sediment and the opportunity for this sediment to be deposited. The relative importance of inundation time, distance from source material, relative roughness and suspended sediment concentration varied across the marsh surface. Wave activity, however, exerted a significant influence on both the temporal and spatial patterns of sediment deposition, particularly through an increase in suspended sediment concentrations and through transport of suspended sediment further up into the mid and high marsh during spring tides. In addition, the region around the mean high water level appears to form a transition zone for processes of sediment transport and deposition, with most deposition taking place around this region. This study also emphasizes the importance of knowing precisely where one's sample stations are within the tidal frame. Modelling exercises must therefore consider spatial and temporal variability in sedimentary processes across a salt marsh surface. In addition, this study suggests sedimentation models developed for sheltered coastal marshes cannot necessarily be applied to open coastal marshes exposed to wave activity.

van Proosdij, Danika; Davidson-Arnott, Robin G. D.; Ollerhead, Jeff

2006-08-01

396

Stochastic description of salt-marsh inundation from mixed astronomical-wind driven tides, with implications for macrophyte growth  

NASA Astrophysics Data System (ADS)

Sea-level rise and sedimentation interact to control productivity on coastal salt marshes since the mean sea level influences flood frequency. Irregularly flooded marshes are inundated during spring and storm tides and during extended periods of north-easterly winds. The weak and irregular inundation in marshes may effect rates of decomposition, organic matter accumulation, and the vertical distribution of marsh vegetation. Whereas astronomical tides are predictable, wind driven tides depend on the strength and direction of the wind. Because these systems are stochastic, a non-hydrodynamic approach is used to describe the tides and determine the distribution of water depths. Here we present a description of salt-marsh inundation from mixed astronomical-wind driven tides that removes the astronomical forcing from water level records to determine the role of wind, storms, and forecasting of stochastic platform wetting. Using a 3 year record of water level and wind from sites in Carteret County, North Carolina, we calculate the mean high water (MHW) level and the ratio of inundation for a given elevation and corresponding macrophyte. The frequency of inundation or marsh platform wetting will vary from the frequency of MHW level, yet it is this stochastic wetting process that determines productivity and plant distribution since infrequent flooding may cause stress or hypersaline conditions. An ARIMA model is used to describe this higher order structure of the inundation signal. Wind can be described as an AR1 and a transfer function model is used to determine the dynamic response of the effect of noise and sustained winds on water levels. Harmonic analysis is also performed for comparison of predicted water levels using various tidal constituents to determine the phases and amplitudes and to explore model simplification.

Howell, S. M.; Furbish, D. J.; Morris, J. T.

2009-12-01

397

The greenhouse gas flux and potential global warming feedbacks of a northern macrotidal and microtidal salt marsh  

NASA Astrophysics Data System (ADS)

Conversion of wetlands by drainage for agriculture or other anthropogenic activities could have a negative or positive feedback to global warming (GWF). We suggest that a major predictor of the GWF is salinity of the wetland soil (a proxy for available sulfate), a factor often ignored in other studies. We assess the radiative balance of two northern salt marshes with average soil salinities > 20 ppt, but with high (macro-) and low (micro-) tidal amplitudes. The flux of greenhouse gases from soils at the end of the growing season averaged 485 ± 253 mg m - 2 h - 1, 13 ± 30 µg m - 2 h - 1, and 19 ± 58 µg m - 2 h - 1 in the microtidal marsh and 398 ± 201 mg m - 2 h - 1, 2 ± 26 µg m - 2 h - 1, and 35 ± 77 µg m - 2 h - 1 in the macrotidal marsh for CO2, N2O, and CH4, respectively. High rates of C sequestration mean that loss of these marshes would have a radiative balance of - 981 CO2_eq. m - 2 yr - 1 in the microtidal and - 567 CO2_eq. m - 2 yr - 1 in the macrotidal marsh.

Chmura, Gail L.; Kellman, Lisa; Guntenspergen, Glenn R.

2011-10-01

398

Co-occurrence of habitat-modifying invertebrates: effects on structural and functional properties of a created salt marsh  

Microsoft Academic Search

The roles of co-occurring herbivores that modify habitat structure and ecosystem processes have seldom been examined in manipulative\\u000a experiments or explored in early successional communities. In a created marsh in southern California (USA), we tested the\\u000a individual and combined effects of two epibenthic invertebrates on nutrient and biomass pools, community structure, and physical\\u000a habitat features. We manipulated snail (Cerithidea californica)

Katharyn E. Boyer; Peggy Fong

2005-01-01

399

Bepaling van de Ondergrondse Biomassa en Produktie van een Aantal Schorreplanten (Sampling Program on Below-Ground Biomass and Productivity in Four Salt Marsh Vegetation Stands).  

National Technical Information Service (NTIS)

During 1979 and 1980 a sampling programme was performed on the below-ground biomass and productivty in four salt marsh vegetation stands. Three of the stands were monospecific, comprising: Elytrigia pungens, Halimione portulacoides and Spartina anglica, a...

M. A. Vink-Lievaart

1983-01-01

400

Methane, carbon dioxide and nitrous oxide fluxes from a temperate salt marsh: Grazing management does not alter Global Warming Potential  

NASA Astrophysics Data System (ADS)

Soil greenhouse gas emissions from cattle grazed and un-grazed temperate upper salt marsh were measured using dark static chambers, monthly for one year. Below-ground gas sampling tubes were also used to measure soil methane (CH4) concentrations. CH4 efflux from grazed and un-grazed salt marsh did not differ significantly although grazing did lead to 'hotspots' of underground CH4 (up to 6% of total air volume) and CH4 efflux (peak of 9 mg m-2 h-1) significantly linked to high soil moisture content, low soil temperatures and the presence of Juncus gerardii. Carbon dioxide (CO2) efflux was greater from the un-grazed marsh (mean of 420 mg m-2 h-1) than the grazed marsh (mean of 333 mg m-2 h-1) throughout most of the year and was positively correlated with the deeper water table and greater soil temperatures. Grazing was not a significant predictor of nitrous oxide (N2O) soil emissions. Global Warming Potential (GWP; over 100 years), calculated from mean yearly chamber fluxes for CH4 and CO2, did not differ significantly with grazing treatment. Seasonal variation in the key drivers of soil greenhouse gas efflux; soil temperature, moisture and water table, plus the presence or absence of aerenchymatous plants such as J. gerardii were more important to the magnitude of greenhouse gas emissions than grazing management per se.

Ford, Hilary; Garbutt, Angus; Jones, Laurence; Jones, Davey L.

2012-11-01

401

[Evolvement of soil quality in salt marshes and reclaimed farmlands in Yancheng coastal wetland].  

PubMed

Through vegetation investigation and soil analysis, this paper studied the evolvement of soil quality during natural vegetation succession and after farmland reclamation in the Yancheng coastal wetland of Jiangsu Province. Along with the process of vegetation succession, the soil physical, chemical, and biological properties in the wetland improved, which was manifested in the improvement of soil physical properties and the increase of soil nutrient contents, microbial biomass, and enzyme activities. Different vegetation type induced the differences in soil properties. Comparing with those in salt marshes, the soil salt content in reclaimed farmlands decreased to 0.01 - 0.04%, the soil microbial biomass and enzyme activities increased, and the soil quality improved obviously. The soil quality index (SQI) in the wetland was in the order of mudflat (0.194) < Suaeda salsa flat (0.233) < Imperata cylindrica flat (0.278) < Spartina alterniflora flat (0.446) < maize field (0.532) < cotton field (0.674) < soybean field (0.826), suggesting that positive vegetation succession would be an effective approach in improving soil quality. PMID:21043105

Mao, Zhi-Gang; Gu, Xiao-Hong; Liu, Jin-E; Ren, Li-Juan; Wang, Guo-Xiang

2010-08-01

402

Distribution of modern salt-marsh foraminifera in the Albemarle–Pamlico estuarine system of North Carolina, USA: Implications for sea-level research  

Microsoft Academic Search

We described the distributions of foraminifera from ten physiographically distinct salt marshes in the Albemarle–Pamlico estuarine system, North Carolina using 193 surface samples. We defined elevation-dependent ecological zones at individual sites using cluster analysis and detrended correspondence analysis. Additionally, seven principal biozones of salt-marsh foraminifera were identified that have distinctive spatial distributions reflecting a pattern of salinity regimes caused by

Andrew C. Kemp; Benjamin P. Horton; Stephen J. Culver

2009-01-01

403

A Population Survey of Members of the Phylum Bacteroidetes Isolated from Salt Marsh Sediments along the East Coast of the United States  

Microsoft Academic Search

The population diversity of cultured isolates of the phylum Bacteroidetes was investigated from salt-marsh sediments. A total of 44 isolates that belonged to this phylum were isolated either from high-dilution plates or from end-dilution most-probable-number (MPN) tubes. The majority of the isolates came from Virginia, with others isolated from salt marshes in Delaware and North Carolina. All the isolates were

C. Lydell; L. Dowell; M. Sikaroodi; P. Gillevet; D. Emerson

2004-01-01

404

Seasonal Changes in the Relative Abundance of Uncultivated Sulfate-Reducing Bacteria in a Salt Marsh Sediment and in the Rhizosphere of Spartina alterniflora  

Microsoft Academic Search

Phylogenetic diversity and community composition of sulfate-reducing bacteria in a salt marsh sediment and in the rhizosphere of Spartina alterniflora were investigated. Uncultivated Desulfobacteriaceae family-related phylotypes were studied by selectively amplifying 16S rRNA gene fragments from DNA extracted from salt marsh rhizosphere samples. Two novel phylotypes were retrieved from rhizosphere samples, with A01 having 89.1% sequence similarity with Desulfococcus multivorans

JULIETTE N. ROONEY-VARGA; RICHARD DEVEREUX; ROBERT S. EVANS

1997-01-01

405

Nitrogen assimilation and short term retention in a nutrient-rich tidal freshwater marsh - a whole ecosystem 15N enrichment study  

NASA Astrophysics Data System (ADS)

An intact tidal freshwater marsh system (3477 m2) was labelled by adding 15N-ammonium as a tracer to the flood water inundating the ecosystem. The appearance and retention of 15N-label in different marsh components (leaves, roots, sediment, leaf litter and invertebrate fauna) was followed over 15 days. This allowed us to elucidate the direct assimilation and dependence on creek-water nitrogen on a relatively short term and provided an unbiased assessment of the relative importance of the various compartments within the ecosystem. Two separate experiments were conducted, one in spring/early summer (May 2002) when plants were young and building up biomass; the other in late summer (September 2003) when macrophytes were in a flowering or early senescent state. Nitrogen assimilation rate (per hour inundated) was >3 times faster in May compared to September. On both occasions, however, the results clearly revealed that the less conspicuous compartments such as leaf litter and ruderal vegetations are more important in nitrogen uptake and retention than the prominent reed (Phragmites australis) meadows. Moreover, short-term nitrogen retention in these nutrient rich marshes occurs mainly via microbial pathways associated with the litter and sediment. Rather than direct uptake by macrophytes, it is the large reactive surface area provided by the tidal freshwater marsh vegetation that is most crucial for nitrogen transformation, assimilation and short term retention in nutrient rich tidal freshwater marshes. Our results clearly revealed the dominant role of microbes in initial nitrogen retention in marsh ecosystems.

Gribsholt, B.; Struyf, E.; Tramper, A.; de Brabandere, L.; Brion, N.; van Damme, S.; Meire, P.; Dehairs, F.; Middelburg, J. J.; Boschker, H. T. S.

2007-01-01

406

Metabolism of low molecular weight organic compounds by sulfate-reducing bacteria in a Delaware salt marsh  

Microsoft Academic Search

Oxidation of acetate, lactate, pyruvate, and ethanol to CO2 in anaerobic salt marsh sediments was rapid, with the oxidation rate being significantly inhibited (60–90% decrease) in the presence of 2 mM sodium molybdate, an inhibitor of sulfate-reducing bacteria (SRB). 2-Bromoethanesulfonic acid (BES), an inhibitor of methanogenic bacteria, generally had no effect on the oxidation rate. Acetate was the only intermediate

Howard J. Dicker; David W. Smith

1985-01-01

407

Stable Isotope and Biochemical Composition of White Perch in a Phragmites Dominated Salt Marsh and Adjacent Waters  

Microsoft Academic Search

Tissue stable isotopes and biochemical condition were compared in two populations of white perch, Morone americana, residing in a Phragmites australis-dominated tidal salt marsh and adjacent open waters of Haverstraw Bay, in the Hudson River estuary, USA. As reported previously\\u000a for other taxa in this system, stable isotope composition of M. americana was influenced by the dominant vegetation present, in

Michael P. Weinstein; Steven Y. Litvin; Vincent G. Guida

2010-01-01

408

Growth patterns of Carolina wolfberry ( Lycium carolinianum L.) in the salt marshes of Aransas National Wildlife Refuge, Texas, USA  

Microsoft Academic Search

The coastal salt marshes of the Aransas National Wildlife Refuge (ANWR), Texas, USA support a wintering population of the\\u000a endangered Whooping Crane (Grus americana). Although the bulk of their winter diet is comprised of blue crabs, berries from the Carolina wolfberry (Lycium carolinianum) can contribute 21–52% of crane energy intake early in the wintering period. Monthly, from November 2003 to

Rachel E. Butzler; Stephen E. Davis

2006-01-01

409

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria were isolated from contaminated estuarine sediment and salt marsh rhizosphere by enrichment using either naphthalene, phenanthrene, or biphenyl as the sole source of carbon and energy. Pasteurization of samples prior to enrichment resulted in isolation of gram-positive, spore-forming bacteria. The isolates were characterized using a variety of phenotypic, morpho- logic, and molecular properties. Identification of

L. L. Daane; I. Harjono; G. J. Zylstra; M. M. Haggblom

2001-01-01

410

Seasonal analyses of arbuscular mycorrhizae, nitrogen-fixing bacteria and growth performance of the salt marsh grass Spartina patens  

Microsoft Academic Search

Seasonal variation of arbuscular mycorrhizal fungi (AMF) in roots of the high salt marsh plant Spartina patens, the diversity of nitrogen-fixing bacteria in the rhizosphere and plant growth performance was studied at key stages of the\\u000a growing season coinciding with major plant phenological stages, i.e., vegetative growth, reproduction and senescence. AMF\\u000a colonization was highest during vegetative growth, with values declining

Allana K. Welsh; David J. Burke; Erik P. Hamerlynck; Dittmar Hahn

2010-01-01

411

Abiotic stress mediates top-down and bottom-up control in a Southwestern Atlantic salt marsh  

Microsoft Academic Search

Increasing evidence has shown that nutrients and consumers interact to control primary productivity in natural systems, but\\u000a how abiotic stress affects this interaction is unclear. Moreover, while herbivores can strongly impact zonation patterns in\\u000a a variety of systems, there are few examples of this in salt marshes. We evaluated the effect of nutrients and herbivores\\u000a on the productivity and distribution

Juan Alberti; Agustina Méndez Casariego; Pedro Daleo; Eugenia Fanjul; Brian Silliman; Mark Bertness; Oscar Iribarne

2010-01-01

412

Role of the Salt Marsh Grass Spartina alterniflora in the Response of Soil-Denitrifying Bacteria to Glucose Enrichment †  

PubMed Central

Long-term incubations of salt marsh soil systems in the presence of glucose resulted in a decrease in the soils' denitrification potential. Addition of nitrate or the presence of living Spartina alterniflora reversed this effect, indicating that Spartina, through the establishment of an oxidized rhizosphere where nitrification can occur, enables the denitrifying bacteria to adequately compete with the less energetically efficient components of the anaerobic soil microbial community.

Sherr, B. F.; Payne, W. J.

1979-01-01

413

Salt marsh-atmosphere exchange of energy, water vapor, and carbon dioxide: Effects of tidal flooding and biophysical controls  

Microsoft Academic Search

The degree to which short-duration, transient floods modify wetland-atmosphere exchange of energy, water vapor, and carbon dioxide (CO2) is poorly documented despite the significance of flooding in many wetlands. This study explored the effects of transient floods on salt marsh-atmosphere linkages. Eddy flux, micrometeorological, and other field data collected during two tidal phases (daytime versus nighttime high tides) quantified the

Kevan B. Moffett; Adam Wolf; Joe A. Berry; Steven M. Gorelick

2010-01-01

414

Soil chemical and biochemical properties of a salt-marsh alluvial Spanish area after long-term reclamation  

Microsoft Academic Search

Marisma, one of the largest salt-marsh alluvial areas in SW Spain, has been reclaimed since 1970 by artificial drainage and\\u000a amendment with phosphogypsum (PG) so as to reduce Na+ saturation. Within the reclaimed area, two 250-?×?20-m plots were treated as follows: (1) amendment with 25 Mg\\/ha of PG every\\u000a 2 to 3 years between 1979 and 2003 (plot PY); (2) like PY

Vito Armando Laudicina; Maria Dolores Hurtado; Luigi Badalucco; Antonio Delgado; Eristanna Palazzolo; Michele Panno

2009-01-01

415

Fractionation of metals and As in sediments from a biosphere reserve (Odiel salt marshes) affected by acidic mine drainage  

Microsoft Academic Search

The Odiel salt marshes (Marismas del Odiel) are an important nature area declared a Biosphere Reserve, but they are greatly\\u000a affected by pollution from the Odiel River. Surface sediments from this area were analysed using the latest version of the\\u000a BCR sequential extraction procedure to determine the fractionation of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn among

José Morillo; José Usero; Raquel Rojas

2008-01-01

416

Quantitative vertical zonation of salt-marsh foraminifera for reconstructing former sea level; an example from New Jersey, USA.  

NASA Astrophysics Data System (ADS)

We present a quantitative technique to reconstruct sea level from assemblages of salt-marsh foraminifera using partitioning around medoids (PAM) and linear discriminant functions (LDF). The modern distribution of foraminifera was described from 62 surface samples at three salt marshes in southern New Jersey. PAM objectively estimated the number and composition of assemblages present at each site and showed that foraminifera adhered to the concept of elevation-dependent ecological zones, making them appropriate sea-level indicators. Application of PAM to a combined dataset identified five distinctive biozones occupying defined elevation ranges, which were similar to those identified elsewhere on the U.S. mid-Atlantic coast. Biozone A had high abundances of Jadammina macrescens and Trochammina inflata; biozone B was dominated by Miliammina fusca; biozone C was associated with Arenoparrella mexicana; biozone D was dominated by Tiphotrocha comprimata and biozone E was dominated by Haplophragmoides manilaensis. Foraminiferal assemblages from transitional and high salt-marsh environments occupied the narrowest elevational range and are the most precise sea-level indicators. Recognition of biozones in sequences of salt-marsh sediment using LDFs provides a probabilistic means to reconstruct sea level. We collected a core to investigate the practical application of this approach. LDFs indicated the faunal origin of 38 core samples and in cross-validation tests were accurate in 54 of 56 cases. We compared reconstructions from LDFs and a transfer function. The transfer function provides smaller error terms and can reconstruct smaller RSL changes, but LDFs are well suited to RSL reconstructions focused on larger changes and using varied assemblages. Agreement between these techniques suggests that the approach we describe can be used as an independent means to reconstruct sea level or, importantly, to check the ecological plausibility of results from other techniques.

Kemp, Andrew C.; Horton, Benjamin P.; Vann, David R.; Engelhart, Simon E.; Grand Pre, Candace A.; Vane, Christopher H.; Nikitina, Daria; Anisfeld, Shimon C.

2012-10-01

417

Physicochemical environments and tolerances of cyprinodontoid fishes found in estuaries and salt marshes of eastern North America  

Microsoft Academic Search

Individuals of 28 species of cyprinodontoid fishes have been reported from estuaries\\/salt marshes of the Atlantic and Gulf coasts of North America. Some species show limited latitudinal distributions and\\/or occupy a limited range of habitats; others are widely distributed and\\/or occupy a wide range of habitats.A literature survey was made of conditions of water temperature, dissolved-oxygen (DO) concentrations, and salinities

Frank G. Nordlie

2006-01-01

418

An ecological study of a natural population of diamondback terrapins ( Malaclemys t. terrapin ) in a Delaware salt marsh  

Microsoft Academic Search

A two-year study of a population of the northernediamondback terrapin (Malaclemys t. terrapin) was undertaken in a salt marsh in Delaware. Population size estimates based on markrelease-recapture data indicate an early\\u000a season mean population size of 1655 individuals during June of 1975, declining to a mean of 378 by August. Captures per unit\\u000a effort declined during this same period, supporting

L. E. Hurd; G. W. Smedes; T. A. Dean

1979-01-01

419

The effect of sewage sludge on salt-marsh denitrifying bacteria  

Microsoft Academic Search

Sewage sludge was applied biweekly to the soil surface of a shortSpartina alterniflora marsh in order to evaluate the marsh’s ability to assimilate the sludge nitrogen. After nine months there was a significant\\u000a decrease of the denitrification potential in the first 15cm of the soil profile. In laboratory experiments the sludge was\\u000a shown to have an immediate inhibitory effect on

Barry F. Sherr; William J. Payne

1981-01-01

420

Co-development of wetland soils and benthic invertebrate communities following salt marsh creation  

Microsoft Academic Search

The development of wetland soil characteristics andbenthic invertebrate communities were evaluated increated Spartina alterniflorasalt marshes inNorth Carolina ranging in age from 1 to 25 years-old.A combination of measurements from different-agecreated marshes as well as periodic measurements overtime on two marshes were used to (1) document rates ofwetland pedogenesis, especially soil organic matter,and, (2) explore relationships between soil andbenthic invertebrate community

C. Craft

2000-01-01

421

Effects of sediment slurry enrichment on salt marsh rehabilitation: Plant and soil responses over seven years  

Microsoft Academic Search

In deltaic marshes, mineral sediment promotes positive elevation change and counters subsidence and sea level rise. In many\\u000a such marshes sediment deficits result in wetland loss. One new way to address sediment deficiency is to supply marshes with\\u000a sediments in a slurry that deposits the sediment in a thin layer over a large area. The long-term effects of this strategy

Matthew G. Slocum; Irving A. Mendelssohn; Nathan L. Kuhn

2005-01-01

422

Salt tolerance underlies the cryptic invasion of North American salt marshes by an introduced haplotype of the common reed Phragmites australis (Poaceae)  

USGS Publications Warehouse

A distinct, non-native haplotype of the common reed Phragmites australis has become invasive in Atlantic coastal Spartina marshes. We compared the salt tolerance and other growth characteristics of the invasive M haplotype with 2 native haplotypes (F and AC) in greenhouse experiments. The M haplotype retained 50% of its growth potential up to 0.4 M NaCl, whereas the F and AC haplotypes did not grow above 0.1 M NaCl. The M haplotype produced more shoots per gram of rhizome tissue and had higher relative growth rates than the native haplotypes on both freshwater and saline water treatments. The M haplotype also differed from the native haplotypes in shoot water content and the biometrics of shoots and rhizomes. The results offer an explanation for how the M haplotype is able to spread in coastal salt marshes and support the conclusion of DNA analyses that the M haplotype is a distinct ecotype of P. australis.

Vasquez, E.A.; Glenn, E.P.; Brown, J.J.; Guntenspergen, G.R.; Nelson, S.G.

2005-01-01

423

The influence of Sarcocornia fruticosa on retention of PAHs in salt marsh sediments (Sado estuary, Portugal).  

PubMed

Depth concentration profiles of PAHs, organic carbon and dissolved oxygen in non-colonised sediments and sediments colonised by Sarcocornia fruticosa from Mitrena salt marsh (Sado, Portugal) were determined in November 2004 and April 2005. Belowground biomass and PAH levels in below and aboveground material were also determined. In both periods, colonised sediments were oxygenated until 15-cm, rich in organic carbon (max 4.4%) and presented much higher PAH concentrations (max. 7.1 microg g(-1)) than non-colonised sediments (max. 0.55 microg g(-1)). Rooting sediments contained the highest PAH concentrations. The five- and six-ring compounds accounted to 50-75% of the total PAHs in colonised sediments, while only to 30% in non-colonised sediments. The elevated concentrations of PAHs in colonised sediments may be attributed to the transfer of dissolved PAH compounds towards the roots as plant uptake water and subsequent sequestration onto organically rich particles. A phase-partitioning mechanism probably explains the higher retention of the heavier PAHs. In addition oxygenated conditions of the rooting sediments favour the degradation of the lighter PAHs and explain the elevated proportion of the heavier compounds. Below and aboveground materials presented lower PAH concentrations (0.18-0.38 microg g(-1)) than colonised sediments. Only 3- and 4-PAHs were quantified in aboveground material, reflecting either preferential translocation of lighter compounds from roots or atmospheric deposition. PMID:18068208

Martins, Marta; Ferreira, Ana Maria; Vale, Carlos

2007-12-18

424

The effect of multiple stressors on salt marsh end-of-season biomass  

USGS Publications Warehouse

It is becoming more apparent that commonly used statistical methods (e.g., analysis of variance and regression) are not the best methods for estimating limiting relationships or stressor effects. A major challenge of estimating the effects associated with a measured subset of limiting factors is to account for the effects of unmeasured factors in an ecologically realistic matter. We used quantile regression to elucidate multiple stressor effects on end-of-season biomass data from two salt marsh sites in coastal Louisiana collected for 18 yr. Stressor effects evaluated based on available data were flooding, salinity, air temperature, cloud cover, precipitation deficit, grazing by muskrat, and surface water nitrogen and phosphorus. Precipitation deficit combined with surface water nitrogen provided the best two-parameter model to explain variation in the peak biomass with different slopes and intercepts for the two study sites. Precipitation deficit, cloud cover, and temperature were significantly correlated with each other. Surface water nitrogen was significantly correlated with surface water phosphorus and muskrat density. The site with the larger duration of flooding showed reduced peak biomass, when cloud cover and surface water nitrogen were optimal. Variation in the relatively low salinity occurring in our study area did not explain any of the variation in Spartina alterniflora biomass. ?? 2006 Estuarine Research Federation.

Visser, J. M.; Sasser, C. E.; Cade, B. S.

2006-01-01

425

The role of herbicides in the erosion of salt marshes in eastern England.  

PubMed

Laboratory studies and field trials were conducted to investigate the role of herbicides on saltmarsh vegetation, and their possible significance to saltmarsh erosion. Herbicide concentrations within the ranges present in the aquatic environment were found to reduce the photosynthetic efficiency and growth of both epipelic diatoms and higher saltmarsh plants in the laboratory and in situ. The addition of sublethal concentrations of herbicides resulted in decreased growth rates and photosynthetic efficiency of diatoms and photosynthetic efficiency of higher plants. Sediment stability also decreased due to a reduction in diatom EPS production. There was qualitative evidence that diatoms migrated deeper into the sediment when the surface was exposed to simazine, reducing surface sediment stability by the absence of a cohesive biofilm. Sediment loads on leaves severely reduced photosynthesis in Limonium vulgare. This, coupled with reduced carbon assimilation from the effects of herbicides, could have large negative consequences for plant productivity and over winter survival of saltmarsh plants. The data support the hypothesis that sublethal herbicide concentrations could be playing a role in the increased erosion of salt marshes that has occurred over the past 40 years. PMID:12535594

Mason, C F; Underwood, G J C; Baker, N R; Davey, P A; Davidson, I; Hanlon, A; Long, S P; Oxborough, K; Paterson, D M; Watson, A

2003-01-01

426

Mercury in sediments and vegetation in a moderately contaminated salt marsh (Tagus Estuary, Portugal).  

PubMed

Depth variations of total mercury (Hg) and methylmercury (MeHg) concentrations were studied in cores from non-colonized sediments, sediments colo