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1

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

2

Mercury in salt marshes ecosystems: Halimione portulacoides as biomonitor  

Microsoft Academic Search

Mercury concentrations were quantified in Halimione portulacoides (roots, stems and leaves) as well as in sediments from eight Portuguese estuarine systems, covering seventeen salt marshes with distinct degrees of mercury contamination. The concentration of mercury in the sediments ranged from 0.03 to 17.0?gg?1. The results show that the accumulation of mercury differed according to the organ of the plant examined

M. Válega; A. I. Lillebø; M. E. Pereira; I. Caçador; A. C. Duarte; M. A. Pardal

2008-01-01

3

DIEL FLUX OF DISSOLVED CARBOHYDRATE IN A SALT MARSH AND A SIMULATED ESTUARINE ECOSYSTEM  

EPA Science Inventory

The concentrations of total dissolved carbohydrate (TCHO), monosaccharide (MCHO) and polysaccharide (PCHO) were followed over a total of ten diel cycles in a salt marsh and a 13 cu m seawater tank simulating an estuarine ecosystem. Their patterns are compared to those for total d...

4

A trophic cascade triggers collapse of a salt-marsh ecosystem with intensive recreational fishing.  

PubMed

Overexploitation of predators has been linked to the collapse of a growing number of shallow-water marine ecosystems. However, salt-marsh ecosystems are often viewed and managed as systems controlled by physical processes, despite recent evidence for herbivore-driven die-off of marsh vegetation. Here we use field observations, experiments, and historical records at 14 sites to examine whether the recently reported die-off of northwestern Atlantic salt marshes is associated with the cascading effects of predator dynamics and intensive recreational fishing activity. We found that the localized depletion of top predators at sites accessible to recreational anglers has triggered the proliferation of herbivorous crabs, which in turn results in runaway consumption of marsh vegetation. This suggests that overfishing may be a general mechanism underlying the consumer-driven die-off of salt marshes spreading throughout the western Atlantic. Our findings support the emerging realization that consumers play a dominant role in regulating marine plant communities and can lead to ecosystem collapse when their impacts are amplified by human activities, including recreational fishing. PMID:22834380

Altieri, Andrew H; Bertness, Mark D; Coverdale, Tyler C; Herrmann, Nicholas C; Angelini, Christine

2012-06-01

5

Mercury in salt marshes ecosystems: Halimione portulacoides as biomonitor.  

PubMed

Mercury concentrations were quantified in Halimione portulacoides (roots, stems and leaves) as well as in sediments from eight Portuguese estuarine systems, covering seventeen salt marshes with distinct degrees of mercury contamination. The concentration of mercury in the sediments ranged from 0.03 to 17.0 microg g(-1). The results show that the accumulation of mercury differed according to the organ of the plant examined and the concentration of mercury in the sediments. Higher mercury concentrations were found in the roots (up to 12.9 microg g(-1)) followed by the leaves (up to 0.12 microg g(-1)), while the stems had the lowest concentrations (up to 0.056 microg g(-1)). A linear model explained the relation between the concentrations of mercury in the different plant organs: roots and stems (R(adj)(2)=0.75), stems and leaves (R(adj)(2)=0.85) and roots and leaves (R(adj)(2)=0.78). However, the results show that the variation of mercury concentration in the roots versus mercury concentration in the sediments was best fitted by a sigmoidal model (R(adj)(2)=0.89). Mercury accumulation in the roots can be described in three steps: at a low range of mercury concentrations in the sediments (from 0.03 up to 2 microg g(-1)), the accumulation of mercury in roots is also low reaching a maximum concentration of 1.3 microg g(-1); the highest rates of mercury accumulation in the roots occur in a second step, until the concentrations of mercury in the sediments reach approximately 4.5 microg g(-1); after reaching this maximum value, the rate of mercury accumulation in the roots slows down leading to a plateau in the concentration of mercury in the roots of about 9.4 microg g(-1), which corresponds to a mercury concentration in the sediments of about 11 microg g(-1). A linear model explained also the accumulation of mercury in leaves versus the mercury concentration in the sediments (R(adj)(2)=0.88). Differences in responses of roots and leaves are explained by the dynamics of the plant organs: old roots are mineralised in situ close to new roots, while leaves are renewed. Previous studies have already shown that H. portulacoides is a bioindicator for mercury and the results from this work sustain that H. portulacoides may also be used as a biomonitor for mercury contamination in salt marshes. Nevertheless, caution should be taken in the application of the models, concerning the life cycle of the species and the spatial variability of the systems. PMID:18799184

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

2008-11-01

6

Microbial-Malathion Interaction in Artificial Salt-Marsh Ecosystems. Effect and Degradation.  

National Technical Information Service (NTIS)

Malathion is rapidly degraded in vitro by salt-marsh bacteria to malathion-monocarboxylic acid, malathion-dicarboxylic acid and various phosphothionates as a result of carboxyesterase cleavage. In addition, some expected phosphatase activity produces desm...

A. W. Bourquin

1975-01-01

7

DEVELOPING INDICATORS OF SALT MARSH HEALTH  

EPA Science Inventory

We relate plant zonation in salt marshes to key ecosystem services such as erosion control and wildlife habitat. Ten salt marshes in Narragansett Bay, with similar geological bedrock and sea exchange, were identified to examine plant zonation. Sub-watersheds adjacent to the salt ...

8

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

9

Hemigrapsus sanguineus in Long Island salt marshes: experimental evaluation of the interactions between an invasive crab and resident ecosystem engineers  

PubMed Central

The invasive Asian shore crab, Hemigrapsus sanguineus, has recently been observed occupying salt marshes, a novel environment for this crab species. As it invades this new habitat, it is likely to interact with a number of important salt marsh species. To understand the potential effects of H. sanguineus on this ecosystem, interactions between this invasive crab and important salt marsh ecosystem engineers were examined. Laboratory experiments demonstrated competition for burrows between H. sanguineus and the native fiddler crab, Uca pugilator. Results indicate that H. sanguineus is able to displace an established fiddler crab from its burrow. Feeding experiments revealed that the presence of H. sanguineus has a significantly negative impact on the number as well as the biomass of ribbed mussels (Geukensia demissa) consumed by the green crab, Carcinus maenas, although this only occurred at high predator densities. In addition, when both crabs foraged together, there was a significant shift in the size of mussels consumed. These interactions suggests that H. sanguineus may have long-term impacts and wide-ranging negative effects on the saltmarsh ecosystem.

Fournier, Alexa M.; Furman, Bradley T.; Carroll, John M.

2014-01-01

10

TOWARDS DEVELOPING INDICATORS OF SALT MARSH CONDITION  

EPA Science Inventory

Five ecosystem services: water quality maintenance, erosion and flood control, recreation and cultural use, wildlife habitat, and food production were identified from the literature as key services to characterize salt marshes of high integrity. We describe a systems approach to ...

11

Oregon Salt Marshes: How Blue are They?  

EPA Science Inventory

Two important ecosystem services of wetlands are carbon sequestration and filtration of nutrients and particulates. We quantified the carbon and nitrogen accumulation rates in salt marshes at 135 plots distributed across eight estuaries located in Oregon, USA. Net carbon and ...

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

Ecosystem Functions of Tidal Fresh, Brackish, and Salt Marshes on the Georgia Coast  

Microsoft Academic Search

We examined patterns of habitat function (plant species richness), productivity (plant aboveground biomass and total C), and\\u000a nutrient stocks (N and P in aboveground plant biomass and soil) in tidal marshes of the Satilla, Altamaha, and Ogeechee Estuaries\\u000a in Georgia, USA. We worked at two sites within each salinity zone (fresh, brackish, and saline) in each estuary, sampling\\u000a a transect

Kazimierz Wi?ski; Hongyu Guo; Christopher B. Craft; Steven C. Pennings

2010-01-01

14

The bly creek ecosystem study: Phosphorus transport within a euhaline salt marsh basin, North Inlet, South Carolina  

NASA Astrophysics Data System (ADS)

Phosphorus transport through the tidal creek linking the Bly Creek basin (North Inlet, South Carolina) and the surrounding water body was studied on 34 tidal cycles between 20 June 1983 and 19 June 1984. Annual estimates of phosphorus input to the basin via streamwater, groundwater, and via streamwater, groundwater, and rain totalled 19.6 kg P·y -1; PO 4 export from the basin was not significant. Within the basin, the salt marsh was shown to be an important sink for PO 4 (207 kg P·y -1) while the oyster reef community exported a statistically insignificant 7.7 kg P·y -1. The data suggest that the source of the PO 4 to the salt marsh is the water column or benthic sediments of the tidal creek. The salt marsh was a significant sink for particulate phosphorus, but those uptakes were less than the error on the insignificant fluxes into the basin via the water column. The oyster reef community was a statistically significant sink for total phosphorus (98 kg P·y -1).

Dame, Richard F.; Wolaver, Thomas G.; Williams, Thomas M.; Spurrier, John D.; Miller, Anne B.

15

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

16

Hydrocarbon degradation potential of salt marsh plant–microorganisms associations  

Microsoft Academic Search

Estuaries are often considered sinks for contaminants and the cleanup of salt marshes, sensitive ecosystems with a major ecological\\u000a role, should be carried out by means of least intrusive approaches, such as bioremediation. This study was designed to evaluate\\u000a the influence of plant–microorganisms associations on petroleum hydrocarbons fate in salt marshes of a temperate estuary (Lima\\u000a River, NW Portugal). Sediments

Hugo RibeiroAna; Ana P. Mucha; C. Marisa R. Almeida; Adriano A. Bordalo

2011-01-01

17

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

18

Salt marsh vegetation change in response to tidal restriction  

NASA Astrophysics Data System (ADS)

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, while the duration of restriction at the other sites ranges from less than ten years to several decades. The data indicate that with tidal restriction there is a substantial reduction in soil water salinity, lowering of the water table level, as well as a relative drop in the marsh surface elevation. These factors are considered to favor the establishment and spread of Phragmites australis (common reed grass) and other less salt-tolerant species, with an attendant loss of Spartina-dominated marsh. Based on detailed vegetation mapping of the study sites, a generalized scheme is presented to describe the sequence of vegetation change from typical Spartina- to Phragmites-dominated marshes. The restoration of these Phragmites systems is feasible following the reintroduction of tidal flow. At several sites dominated by Phragmites, tidal flow was reintroduced after two decades of continuous restriction, resulting in a marked reduction in Phragmites height and the reestablishment of typical salt marsh vegetation along creekbanks. It is suggested that large-scale restoration efforts be initiated in order that these degraded systems once again assume their roles within the salt marsh-estuarine ecosystem.

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

1984-03-01

19

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

20

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

21

A Review of Tidal Salt Marsh Morphodynamics  

NASA Astrophysics Data System (ADS)

We now understand that, morphologically, natural tidal marshes are generally near or progressing rapidly toward dynamic equilibrium with sediment supply, vegetative growth and relative sea level, rather than far out of equilibrium on a slow evolution toward geologic maturity. The last fifteen years have been marked by major advances in the observation of sedimentation and accretion patterns in tidal salt marshes which reinforce the above interpretation. This paper reviews and synthesizes advances since the late 1980s in our understanding of tidal salt marsh morphodynamics. Recent work has shown that allochthonous deposition patterns on the marsh are controlled primarily by source concentration, distance from that source, and duration of inundation (in turn determined by marsh elevation). Because deposition is proportional to inundation period, inorganic accretion tends to increase or decrease with accelerated or decelerated sea level rise, allowing the accretion rate to similarly fluctuate. Feedback between proximity to sediment source and duration of inundation causes relatively uniform accretion to be characterized by highest marsh elevations adjacent to tidal creeks. Since physical stress on vegetation increases with inundation, plant density and accretion of organic matter is reduced as inundation period increases, a pattern opposite to allochthonous deposition. Among systems dominated by allochthonous sediment, microtidal marshes are more reliant on storm and flood sedimentation and horizontally expand and retreat more quickly than macrotidal marshes, while the latter are more likely to persist during periods of accelerated sea level rise. The density, width and depth of salt marsh creeks all increase with increased tidal prism. Along barrier coastlines, greater tidal range is associated with more frequent inlet spacing, shallower channels, flood-dominance, and higher marsh elevation at equilibrium. Smaller tidal range results in greater inlet spacing, deeper channels, ebb-dominance and lower marsh elevation.

Friedrichs, C. T.; Perry, J. E.

2001-05-01

22

Carbon and Nitrogen Accumulation Rates in Salt Marshes in Oregon, USA  

EPA Science Inventory

Two important ecosystem services of wetlands are carbon sequestration and filtration of nutrients and particulates. We quantified the carbon and nitrogen accumulation rates in salt marshes at 135 plots distributed across eight estuaries located in Oregon, USA. Net carbon and ...

23

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

24

Changes in benthic algal attributes during salt marsh restoration  

Microsoft Academic Search

To assess attributes of algal assemblages as indicators of salt marsh restoration, we chose eight pairs of salt marshes in\\u000a North Carolina, USA, each pair with one restored marsh (from 1 to 28 years old) and a nearby existing salt marsh. Algae on\\u000a both Spartina alterniflora and sediments (sediment algae) were collected in each marsh during spring and summer 1998

Lei Zheng; R. Jan Stevenson; Christopher Craft

2004-01-01

25

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

26

The role of salt marshes in the Mira estuary (Portugal)  

Microsoft Academic Search

The Mira estuary is a narrow entrenched pristine estuary of the Ria type, about 30 km long. It comprises an area of 285 ha\\u000a of salt marsh, of which250 ha have been proposed for reclamation for aquaculture. Dredging, village and recreation development\\u000a menace the yet undisturbed estuarine ecosystem. To assess the biological importance of this wetland, a multidisciplinary study\\u000a was

M. J. Costa; Fernando Catarino; Alexandre Bettencourt

2001-01-01

27

Without Blue Crabs, Southern Salt Marshes Wash Away  

NSF Publications Database

... of this News Tip: Without Blue Crabs, Southern Salt Marshes Wash Away Ocean Drilling Program ... Technology Research Without Blue Crabs, Southern Salt Marshes Wash Away The blue crab harvest needs ...

28

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

29

Geographic variation in salt marsh structure and function.  

PubMed

We examined geographic variation in the structure and function of salt marsh communities along the Atlantic and Gulf coasts of the United States. Focusing on the arthropod community in the dominant salt marsh plant Spartina alterniflora, we tested two hypotheses: first, that marsh community structure varies geographically, and second, that two aspects of marsh function (response to eutrophication and addition of dead plant material) also vary geographically. We worked at eleven sites on the Gulf Coast and eleven sites on the Atlantic Coast, dividing each coast up into two geographic areas. Abiotic conditions (tidal range, soil organic content, and water content, but not soil salinity), plant variables (Spartina nitrogen content, height, cover of dead plant material, but not live Spartina percent cover or light interception), and arthropod variables (proportional abundances of predators, sucking herbivores, stem-boring herbivores, parasitoids, and detritivores, but not total arthropod numbers) varied among the four geographic regions. Latitude and mean tidal range explained much of this geographic variation. Nutrient enrichment increased all arthropod functional groups in the community, consistent with previous experimental results, and had similar effects in all geographic regions, contrary to our hypothesis, suggesting widespread consistency in this aspect of ecosystem function. The addition of dead plant material had surprisingly little effect on the arthropod community. Our results caution against the uncritical extrapolation of work done in one geographic region to another, but indicate that some aspects of marsh function may operate in similar ways in different geographic regions, despite spatial variation in community structure. PMID:22614261

McCall, Brittany D; Pennings, Steven C

2012-11-01

30

Ecophysiological adaptations of coastal halophytes from foredunes and salt marshes  

Microsoft Academic Search

Ecophysiological strategies of coastal halophytes from foredunes and salt marshes are discussed. A comparison is made of the factors that limit growth in salt marshes and sand dunes. In salt marshes, zonation and succession are primarily governed by variation in soil salinity, which strongly depends on inundation with seawater. Results are described of experiments which aim at separating salinity and

J. Rozema; P. Bijwaard; G. Prast; R. Broekman

1985-01-01

31

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

32

Recent Trends in Bird Abundance on Rhode Island Salt Marshes  

EPA Science Inventory

Salt marsh habitat is under pressure from development on the landward side, and sea level rise from the seaward side. The resulting loss of habitat is potentially disastrous for salt marsh dependent species. To assess the population status of three species of salt marsh dependent...

33

Microbial community analysis of a coastal salt marsh affected by the Deepwater Horizon oil spill.  

PubMed

Coastal salt marshes are highly sensitive wetland ecosystems that can sustain long-term impacts from anthropogenic events such as oil spills. In this study, we examined the microbial communities of a Gulf of Mexico coastal salt marsh during and after the influx of petroleum hydrocarbons following the Deepwater Horizon oil spill. Total hydrocarbon concentrations in salt marsh sediments were highest in June and July 2010 and decreased in September 2010. Coupled PhyloChip and GeoChip microarray analyses demonstrated that the microbial community structure and function of the extant salt marsh hydrocarbon-degrading microbial populations changed significantly during the study. The relative richness and abundance of phyla containing previously described hydrocarbon-degrading bacteria (Proteobacteria, Bacteroidetes, and Actinobacteria) increased in hydrocarbon-contaminated sediments and then decreased once hydrocarbons were below detection. Firmicutes, however, continued to increase in relative richness and abundance after hydrocarbon concentrations were below detection. Functional genes involved in hydrocarbon degradation were enriched in hydrocarbon-contaminated sediments then declined significantly (p<0.05) once hydrocarbon concentrations decreased. A greater decrease in hydrocarbon concentrations among marsh grass sediments compared to inlet sediments (lacking marsh grass) suggests that the marsh rhizosphere microbial communities could also be contributing to hydrocarbon degradation. The results of this study provide a comprehensive view of microbial community structural and functional dynamics within perturbed salt marsh ecosystems. PMID:22815990

Beazley, Melanie J; Martinez, Robert J; Rajan, Suja; Powell, Jessica; Piceno, Yvette M; Tom, Lauren M; Andersen, Gary L; Hazen, Terry C; Van Nostrand, Joy D; Zhou, Jizhong; Mortazavi, Behzad; Sobecky, Patricia A

2012-01-01

34

Microbial Community Analysis of a Coastal Salt Marsh Affected by the Deepwater Horizon Oil Spill  

PubMed Central

Coastal salt marshes are highly sensitive wetland ecosystems that can sustain long-term impacts from anthropogenic events such as oil spills. In this study, we examined the microbial communities of a Gulf of Mexico coastal salt marsh during and after the influx of petroleum hydrocarbons following the Deepwater Horizon oil spill. Total hydrocarbon concentrations in salt marsh sediments were highest in June and July 2010 and decreased in September 2010. Coupled PhyloChip and GeoChip microarray analyses demonstrated that the microbial community structure and function of the extant salt marsh hydrocarbon-degrading microbial populations changed significantly during the study. The relative richness and abundance of phyla containing previously described hydrocarbon-degrading bacteria (Proteobacteria, Bacteroidetes, and Actinobacteria) increased in hydrocarbon-contaminated sediments and then decreased once hydrocarbons were below detection. Firmicutes, however, continued to increase in relative richness and abundance after hydrocarbon concentrations were below detection. Functional genes involved in hydrocarbon degradation were enriched in hydrocarbon-contaminated sediments then declined significantly (p<0.05) once hydrocarbon concentrations decreased. A greater decrease in hydrocarbon concentrations among marsh grass sediments compared to inlet sediments (lacking marsh grass) suggests that the marsh rhizosphere microbial communities could also be contributing to hydrocarbon degradation. The results of this study provide a comprehensive view of microbial community structural and functional dynamics within perturbed salt marsh ecosystems.

Beazley, Melanie J.; Martinez, Robert J.; Rajan, Suja; Powell, Jessica; Piceno, Yvette M.; Tom, Lauren M.; Andersen, Gary L.; Hazen, Terry C.; Van Nostrand, Joy D.; Zhou, Jizhong; Mortazavi, Behzad; Sobecky, Patricia A.

2012-01-01

35

Evaluation of salt marsh hydrology using radium as a tracer  

Microsoft Academic Search

Radium isotopes provide unique and important information concerning water exchange in a salt marsh-tidal creek system. Seasonal radium data collected over five tidal cycles from a creek draining a South Carolina salt marsh, radium and thorium data from the adjacent marsh sediments and interstitial water radium data from the drainage basin are modeled to yield residence times of water in

M. S. Bollinger; W. S. Moore

1993-01-01

36

Evaluation of salt marsh hydrology using radium as a tracer  

Microsoft Academic Search

Radium isotopes provide unique and important information concerning water exchange in a salt marsh-tidal creek system. Seasonal radium data collected over five tidal cycles from a creek draining a South Carolina salt marsh, radium and thorium data from the adjacent marsh sediments, and interstitial water radium data from the drainage basin are modeled to yield residence times of water in

M. S. Bollinger; W. S. Moore

1993-01-01

37

The Effects of Tidal Export from Salt Marsh Ditches on Estuarine Water Quality and Plankton Communities  

Microsoft Academic Search

Salt marshes are an important transition zone between terrestrial and marine ecosystems, and in their natural state, they\\u000a often function to cycle or trap terrestrially derived nutrients and organic matter. Many US salt marshes were ditched during\\u000a the twentieth century, potentially altering their functionality. The goal of this 4-year study was to assess the impact of\\u000a water from ditches within

Florian Koch; Christopher J. Gobler

2009-01-01

38

Controls on salt marsh accretion: A test in salt marshes of Eastern Canada  

Microsoft Academic Search

We used137Cs-dating to determine vertical accretion rates of 15 salt marshes on the Bay of Fundy, the Gulf of St. Lawrence, and the\\u000a Atlantic coast of Nova Scotia. Accretion rates are compared to a number of factors assumed to influence vertical marsh accretion:\\u000a rates of relative sea-level rise, climatic parameters (average daily temperatures and degree days) and latitude (related to

Gail L. Chmura; Grace A. Hung

2004-01-01

39

Crenarchaeal heterotrophy in salt marsh sediments.  

PubMed

Mesophilic Crenarchaeota (also known as Thaumarchaeota) are ubiquitous and abundant in marine habitats. However, very little is known about their metabolic function in situ. In this study, salt marsh sediments from New Jersey were screened via stable isotope probing (SIP) for heterotrophy by amending with a single (13)C-labeled compound (acetate, glycine or urea) or a complex (13)C-biopolymer (lipids, proteins or growth medium (ISOGRO)). SIP incubations were done at two substrate concentrations (30-150??M; 2-10?mg?ml(-1)), and (13)C-labeled DNA was analyzed by terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes. To test for autotrophy, an amendment with (13)C-bicarbonate was also performed. Our SIP analyses indicate salt marsh crenarchaea are heterotrophic, double within 2-3 days and often compete with heterotrophic bacteria for the same organic substrates. A clone library of (13)C-amplicons was screened to find matches to the (13)C-TRFLP peaks, with seven members of the Miscellaneous Crenarchaeal Group and seven members from the Marine Group 1.a Crenarchaeota being discerned. Some of these crenarchaea displayed a preference for particular carbon sources, whereas others incorporated nearly every (13)C-substrate provided. The data suggest salt marshes may be an excellent model system for studying crenarchaeal metabolic capabilities and can provide information on the competition between crenarchaea and other microbial groups to improve our understanding of microbial ecology. PMID:24553469

Seyler, Lauren M; McGuinness, Lora M; Kerkhof, Lee J

2014-07-01

40

Recent volumetric changes in salt marsh soils  

NASA Astrophysics Data System (ADS)

Salt marsh sediment volume decreases from organic decomposition, compaction of solids, and de-watering, and each of these processes may change with age. Variability in the vertical accretion rate within the upper 2 m was determined by assembling results from concurrent application of the 137Cs and 210Pb dating techniques used to estimate sediment age since 1963/1964, and 0 to ca 100+ years before present (yBP), respectively. The relationship between 210Pb and the 137Cs dated accretion rates (Sed 210 and Sed 137, respectively) was linear for 45 salt marsh and mangrove environments. Sed 210 averaged 75% of Sed 137 suggesting that vertical accretion over the last 100+ years is driven by soil organic matter accumulation, as shown for the pre 137Cs dated horizon. The ratio of Sed 210/Sed 137 declines with increasing mineral content. A linear multiple regression equation that includes bulk density and Sed 137 to predict Sed 210 described 97% of the variance in Sed 210. Sediments from Connecticut, Delaware and Louisiana coastal environments dated with 14C indicate a relatively constant sediment accretion rate of 0.13 cm year -1 for 1000-7000 yBP, which occurs within 2 m of today's marsh surface and equals modern sea level rise rates. Soil subsidence is not shown to be distinctly different in these vastly different coastal settings. The major reason why the Sed 137 measurements indicate higher accretion rates than do the Sed 210 measurements is because the former apply to younger sediments where the effects of root growth and decomposition are greater than in the latter. The most intense rates of change in soil volume in organic-rich salt marshes sediments is, therefore, neither in deep or old sediments (>4 m; >1000 years), but within the first several hundreds of years after accumulation. The average changes in organic and inorganic constituents downcore are nearly equal for 58 dated sediment cores from the northern Gulf of Mexico. These parallel changes downcore are best described as resulting from compaction, rather than from organic matter decomposition. Thus most of the volumetric changes in these salt marsh sediments occurs in the upper 2 m, and declines quickly with depth. Extrapolation forwards or backwards, using results from the 210Pb and the 137Cs dating technique appear to be warranted for the types of samples from the environments described here.

Eugene Turner, R.; Milan, Charles S.; Swenson, Erick M.

2006-09-01

41

Comparative Geomorphology of Salt and Tidal Freshwater Marsh Environments  

Microsoft Academic Search

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

G. B. Pasternack

2002-01-01

42

Controls on resilience and stability in a sediment-subsidized salt marsh.  

PubMed

Although the concept of self-design is frequently employed in restoration, reestablishment of primary physical drivers does not always result in a restored ecosystem having the desired ecological functions that support system resilience and stability. We investigated the use of a primary environmental driver in coastal salt marshes, sediment availability, as a means of promoting the resilience and stability of submerging deltaic salt marshes, which are rapidly subsiding due to natural and human-induced processes. We conducted a disturbance-recovery experiment across a gradient of sediment slurry addition to assess the roles of sediment elevation and soil physico-chemical characteristics on vegetation resilience and stability in two restored salt marshes of differing age (a 15-year-old site and a 5-year-old site). Salt marshes that received moderate intensities of sediment slurry addition with elevations at the mid to high intertidal zone (2-11 cm above local mean sea level; MSL) were more resilient than natural marshes. The primary regulator of enhanced resilience and stability in the restored marshes was the alleviation of flooding stress observed in the natural, unsubsidized marsh. However, stability reached a sediment addition threshold, at an elevation of 11 cm above MSL, with decreasing stability in marshes above this elevation. Declines in resilience and stability above the sediment addition threshold were principally influenced by relatively dry conditions that resulted from insufficient and infrequent flooding at high elevations. Although the older restored marsh has subsided over time, areas receiving too much sediment still had limited stability 15 years later, emphasizing the importance of applying the appropriate amount of sediment to the marsh. In contrast, treated marshes with elevations 2-11 cm above MSL were still more resilient than the natural marsh 15 years after restoration, illustrating that when performed correctly, sediment slurry addition can be a sustainable restoration technique. PMID:21830714

Stagg, Camille L; Mendelssohn, Irving A

2011-07-01

43

Salt marshes in the silica budget of the North Sea  

NASA Astrophysics Data System (ADS)

Local scale studies reported the silica recycling of salt marshes to substantially attenuate the dissolved silica (DSi) limitation in coastal waters during summer. To assess the importance of salt marshes in the silica budget of the North Sea, we extrapolate reported DSi exports by local scale studies to salt marsh areas adjacent to the North Sea. The resulting annual average contribution of salt marshes to the DSi budget of the North Sea is estimated to 0.8% of the annual river DSi export. During summer, this contribution may reach 2.4%. Thus, salt marshes likely impact the annual dissolved silica budget of the North Sea only weakly. However, for regions with favorable geographic conditions of low river DSi exports and large marsh areas, salt marsh DSi exports may substantially contribute to coastal DSi budgets. In the English Channel, salt marsh DSi exports are estimated to 16% of river DSi export in summer. However, the low data density calls for additional field research to improve extrapolations and the evaluation of the contribution of salt marsh DSi export to the coastal DSi budgets.

Moosdorf, Nils; Weiss, Andreas; Müller, Frauke; Lauerwald, Ronny; Hartmann, Jens; Worrall, Fred

2014-07-01

44

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...

45

Restoration of urban salt marshes: Lessons from southern California  

Microsoft Academic Search

Extensive restoration efforts in southern California coastal wetlands highlight several challenges for urban salt marsh restoration, including: habitat isolation and fragmentation, impacts from exotic species, the loss of transitional upland habitats, and other alterations to hydrologic and sediment dynamics. Habitat isolation impairs colonization by dispersal-limited plants, so planting becomes essential to achieve diverse salt marshes. Low species richness slows the

John C. Callaway; Joy B. Zedler

2004-01-01

46

Using Avian Communities to Evaluate Salt Marsh Restoration  

Microsoft Academic Search

The objectives of this study were to document avian species inhabiting West River Memorial Park in New Haven, Connecticut and develop goals for restoration of a salt marsh bird community. Restoration goals were based on the breeding season bird community at the restoration site, breeding season communities of less disturbed salt marshes, and a literature review. Community descriptions included relative

Celia Lewis; David G. Casagrande

47

Large methyl halide emissions from south Texas salt marshes  

NASA Astrophysics Data System (ADS)

Coastal salt marshes are natural sources of methyl chloride (CH3Cl) and methyl bromide (CH3Br) to the atmosphere, but measured emission rates vary widely by geography. Here we report large methyl halide fluxes from subtropical salt marshes of south Texas. Sites with the halophytic plant, Batis maritima, emitted methyl halides at rates that are orders of magnitude greater than sites containing other vascular plants or macroalgae. B. maritima emissions were generally highest at midday; however, diurnal variability was more pronounced for CH3Br than CH3Cl, and surprisingly high nighttime CH3Cl fluxes were observed in July. Seasonal and intra-site variability were large, even taking into account biomass differences. Overall, these subtropical salt marsh sites show much higher emission rates than temperate salt marshes at similar times of the year, supporting the contention that low-latitude salt marshes are significant sources of CH3Cl and CH3Br.

Rhew, R. C.; Whelan, M. E.; Min, D.-H.

2014-06-01

48

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...

49

OUTLINE OF A NEW APPROACH TO EVALUATE ECOLOGICAL INTEGRITY OF SALT MARSHES  

EPA Science Inventory

The integrity of coastal salt marshes can be determined from the extent to which they provide key ecosystem services: food and habitat for fish and wildlife, good water quality, erosion and flood control, and recreation and cultural use. An outline of a new approach for linking e...

50

Utilization of invasive tamarisk by salt marsh consumers.  

PubMed

Plant invasions of coastal wetlands are rapidly changing the structure and function of these systems globally. Alteration of litter dynamics represents one of the fundamental impacts of an invasive plant on salt marsh ecosystems. Tamarisk species (Tamarix spp.), which extensively invade terrestrial and riparian habitats, have been demonstrated to enter food webs in these ecosystems. However, the trophic impacts of the relatively new invasion of tamarisk into marine ecosystem have not been assessed. We evaluated the trophic consequences of invasion by tamarisk for detrital food chains in the Tijuana River National Estuarine Research Reserve salt marsh using litter dynamics techniques and stable isotope enrichment experiments. The observations of a short residence time for tamarisk combined with relatively low C:N values indicate that tamarisk is a relatively available and labile food source. With an isotopic (15N) enrichment of tamarisk, we demonstrated that numerous macroinvertebrate taxonomic and trophic groups, both within and on the sediment, utilized 15N derived from labeled tamarisk detritus. Infaunal invertebrate species that took up no or limited 15N from labeled tamarisk (A. californica, enchytraeid oligochaetes, coleoptera larvae) occurred in lower abundance in the tamarisk-invaded environment. In contrast, species that utilized significant 15N from the labeled tamarisk, such as psychodid insects, an exotic amphipod, and an oniscid isopod, either did not change or occurred in higher abundance. Our research supports the hypothesis that invasive species can alter the trophic structure of an environment through addition of detritus and can also potentially impact higher trophic levels by shifting dominance within the invertebrate community to species not widely consumed. PMID:18797931

Whitcraft, Christine R; Levin, Lisa A; Talley, Drew; Crooks, Jeffrey A

2008-11-01

51

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

52

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

53

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

54

Evaluation of salt marsh hydrology using radium as a tracer  

NASA Astrophysics Data System (ADS)

Radium isotopes provide unique and important information concerning water exchange in a salt marsh-tidal creek system. Seasonal radium data collected over five tidal cycles from a creek draining a South Carolina salt marsh, radium and thorium data from the adjacent marsh sediments and interstitial water radium data from the drainage basin are modeled to yield residence times of water in the upper 10 cm of the marsh sediments ranging from less than one to twenty-six hours. Water residence times derived from chambers which directly measure the flux of Ra isotopes to the creek waters agree well with these calculated interstitial water turnover times. Dissolved radium activities in the tidal creek were greater during the summer than during other times of the year. We suspect that seasonal changes in the storage of organic carbon and rates of bioturbation lead to net reduction of radium carrier phases in the marsh sediments during the summer.

Bollinger, M. S.; Moore, W. S.

1993-05-01

55

Effects of wrack burial in salt stressed habitats: Batis maritima in a southwest Atlantic marsh  

Microsoft Academic Search

In coastal salt marshes, mats of wrack (dead plant stems) that are deposited on the marsh by high tides can kill underlying vegetation and initiate secondary succession. The importance of wrack disturbance in northwest Atlantic salt marshes has been a topic of recent debate. The importance of wrack disturbance in southwest Atlantic salt marshes, which experience a very different climate

Steven C. Pennings; Christina L. Richards

1998-01-01

56

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

57

Herbivory Drives the Spread of Salt Marsh Die-Off  

PubMed Central

Salt marsh die-off is a Western Atlantic conservation problem that has recently spread into Narragansett Bay, Rhode Island, USA. It has been hypothesized to be driven by: 1) eutrophication decreasing plant investment into belowground biomass causing plant collapse, 2) boat wakes eroding creek banks, 3) pollution or disease affecting plant health, 4) substrate hardness controlling herbivorous crab distributions and 5) trophic dysfunction releasing herbivorous crabs from predator control. To distinguish between these hypotheses we quantified these variables at 14 Narragansett Bay salt marshes where die-off intensity ranged from <5% to nearly 98%. Nitrogen availability, wave intensity and plant growth did not explain any variation in die-off. Herbivory explained 73% of inter-site variation in die-off and predator control of herbivores and substrate hardness also varied significantly with die-off. This suggests that salt marsh die-off is being largely driven by intense herbivory via the release of herbivorous crabs from predator control. Our results and those from other marsh systems suggest that consumer control may not simply be a factor to consider in marsh conservation, but with widespread predator depletion impacting near shore habitats globally, trophic dysfunction and runaway consumption may be the largest and most urgent management challenge for salt marsh conservation.

Bertness, Mark D.; Brisson, Caitlin P.; Bevil, Matthew C.; Crotty, Sinead M.

2014-01-01

58

NUTRIENT-UPTAKE MODEL IN MARSH ECOSYSTEMS  

EPA Science Inventory

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 nutrient uptake, convers...

59

Methanogenesis and microbial lipid synthesis in anoxic salt marsh sediments  

Microsoft Academic Search

In anoxic salt marsh sediments of Sapelo Island, GA, USA, the vertical distribution of CH4 production was measured in the upper 20 cm of surface sediments in ten locations. In one section of high marsh sediments,\\u000a the concentration and oxidation of acetate in sediment porewaters and the rate and amount of14C acetate and14CO2 incorporation into cellular lipids of the microbial

H. Rodger Harvey; Robert D. Fallon; John S. Patton

1989-01-01

60

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

61

Spatial variability of phosphorus sorption dynamics in Louisiana salt marshes  

NASA Astrophysics Data System (ADS)

(P) biogeochemistry has been studied in multiple wetland ecosystems, though few data exist on P sorption in U.S. Gulf Coast marshes. There also is a limited understanding of how oil spills in coastal zones can influence P dynamics in wetland soils. In this study, we measured P sorption potential, using the P sorption index (PSI), soil properties, and P saturation at increasing distances from the marsh edge in oiled and unoiled marshes in three regions along the southeastern Louisiana coast (Terrebonne Bay, western, and eastern Barataria Bay). Individual PSI values were highly variable, ranging from 19.5 to 175.6 mg P 100 g-1 and varying by at least a factor of five within each of the three regions, and did not significantly differ between regions or between oiled and unoiled marshes. Soil pH, organic matter, total N, N:P ratio, moisture content, cation exchange capacity, and P saturation differed between regions, and all soil parameters showed great variability between and within individual marshes. Extractable iron was the strongest predictor of PSI across all regions, explaining between 51 and 95% of the variability in individual regions. PSI increased with distance from marsh edge in Terrebonne Bay where other soil properties exhibited similar trends. Results suggest mineral composition of marsh soils, influenced by elevation-inundation gradients, are critical in dictating P loading to estuaries and open waters, and overall marsh functioning. Further, within 2 years of the Deepwater Horizon oil spill, oiled marshes are able to sorb phosphorus at comparable levels as unoiled marshes.

Marton, John M.; Roberts, Brian J.

2014-03-01

62

Does vegetation prevent wave erosion of salt marsh edges?  

PubMed

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. PMID:19509340

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

2009-06-23

63

Remote sensing salt marsh biomass and stress detection  

NASA Astrophysics Data System (ADS)

A hand-held radiometer was used to gather spectral radiance data simulating bands 3, 4 and 5 of the Landsat-D Thematic Mapper. Variations in biomass of the salt marsh plant Spartina alterniflora were highly correlated to changes in spectral radiance expressed as the vegetation index or the infrared index. Negative stresses like increased soil salinity and increased concentrations of copper or zinc yielded reductions in biomass which were detected spectrally. Positive stresses like freshwater and sewage effluent additions produced an increase in biomass which also were detected using spectral data. The demonstrated detection of biomass from spectral data was expanded spatially and temporally to estimate net primary productivity of a salt marsh. Remote sensing estimates of production ranged from 5 to 20% of estimates from harvest data. Future applications of this biomass estimation technique, employing data gathered from satellite platforms and from the ground, are discussed for salt marsh systems.

Hardisky, M. A.; Klemas, V.; Daiber, F. C.

64

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

65

Salt marsh response to the effects of physical and biological processes  

NASA Astrophysics Data System (ADS)

Salt marshes are widespread features of the tidal landscape governed by the interacting physical and biological processes. These crucially important ecosystems provide valuable services and are currently threatened by the effects of increasing rates of relative sea level rise (RSLR) and decreasing sediment supply. Although a few studies have analyzed the biomorphological evolution of salt marsh systems, a complete understanding of the two-way feedbacks between physical and biological processes is still lacking. The temporal evolution of marsh elevation is governed by the balance between inorganic and organic accretion rates, and the rate of RSLR. Studies based on field observations and modeling suggest that, in equilibrium conditions, marsh inorganic accretion rates, and the related platform elevations, decrease with distance from the main creek whereas the organic deposition gradually increases. In order to analyze salt marsh responses to the effect of physical and biological processes, about 100 sediment samples were collected on the San Felice salt marsh, Venice Lagoon. For each sample, local coordinates, surface elevations and vegetation cover were detected, whereas inorganic and organic sediment content, together with grain size distribution, were determined and analyzed. Loss On Ignition (LOI) and a double treatment with H2O2 and NaClO, were used to estimate the amount of organic matter in each sample. Particle size analysis was carried out on the inorganic fraction with a Mastersizer that uses laser diffraction techniques to measure the grain size. Our results show that the San Felice salt marsh is characterized by a concave-up profile, as commonly displayed by marshes worldwide. Marsh elevation is highest along the boundary and decreases toward the inner marsh. The inorganic deposition, which is maximum along the marsh edge, decreases with distance from the channel network, because as water moves across the marsh, the velocity is reduced and sediment particles are deposited. In contrast, the organic deposition, dictated by local plant productivity, gradually increases with distance from the channel to balance the decrease in the inorganic deposition and to help the marsh surface to keep pace with current rates of RSLR. Interestingly, we note that the amounts of organic and inorganic sediment display non-monotonically trends. Furthermore, regardless of the method used, the amounts of organic matter show the same qualitative trend, although characterized by different values for a single sample. The grain size of inorganic sediment show a variable distribution between medium sand and clay. In particular, the grains along marsh portions adjacent to the channels are coarser and become gradually finer toward the inner marsh, according to the transport capability of the tidal flow and the decrease in the water velocity away from the main channel. In particular, we observed that the location of the channels is an important factor controlling patterns of inorganic and organic deposition. Our results also suggest that halophytic vegetation species largely contribute to tune marsh elevation and bring new insight on the spatial distribution of organic and inorganic deposition rates.

Roner, Marcella; D'Alpaos, Andrea; Ghinassi, Massimiliano; Franceschinis, Erica; Realdon, Nicola; Marani, Marco

2014-05-01

66

A RAPID NON-DESTRUCTIVE METHOD FOR ESTIMATING ABOVEGROUND BIOMASS OF SALT MARSH GRASSES  

EPA Science Inventory

Understanding the primary productivity of salt marshes requires accurate estimates of biomass. Unfortunately, these estimates vary enough within and among salt marshes to require large numbers of replicates if the averages are to be statistically meaningful. Large numbers of repl...

67

Remote sensing of biomass of salt marsh vegetation in France  

NASA Technical Reports Server (NTRS)

Spectral data (gathered using a hand-held radiometer) and harvest data were collected from four salt marsh vegetation types in Brittany, France, to develop equations predicting live aerial biomass from spectral measurements. Remote sensing estimates of biomass of the general salt marsh community (GSM) and of Spartina alterniflora can be obtained throughout the growing season if separate biomass prediction equations are formulated for different species mixtures (for the GSM) and for different canopy types (for S. alterniflora). Results suggest that remote sensing will not be useful for predicting Halimione portulacoides biomass, but can be used to estimate Puccinellia maritima biomass early in the growing season.

Gross, M. F.; Klemas, V.; Levasseur, J. E.

1988-01-01

68

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...

69

Recent Advances in Our Understanding of Salt Marsh Ecology.  

National Technical Information Service (NTIS)

Our understanding of the ecology of coastal marshes has revolved about the role of this ecosystem as a source and reservoir of energy and nutrients, and as a vital habitat for certain life stages of a number of marine organisms. While recent advances in s...

A. A. Cruz

1980-01-01

70

Ecological responses to tidal restorations of two northern New England salt marshes  

Microsoft Academic Search

Efforts are underway to restore tidal flow in New England salt marshes that were negatively impacted by tidal restrictions.\\u000a We evaluated a planned tidal restoration at Mill Brook Marsh (New Hampshire) and at Drakes Island Marsh (Maine) where partial\\u000a tidal restoration inadvertently occurred. Salt marsh functions were evaluated in both marshes to determine the impacts from\\u000a tidal restriction and the

D. M. Burdick; M. Dionne; R. M. Boumans; F. T. Short

1996-01-01

71

Storm-driven groundwater flow in a salt marsh  

Microsoft Academic Search

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

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

2011-01-01

72

Contingent Valuation of an Urban Salt Marsh Restoration  

Microsoft Academic Search

This paper discusses the validity of the contingent valuation method (CVM) and presents the results of a CVM survey we conducted to estimate the nonmarket value of restoring a salt marsh in New Haven, Connecticut. The literature suggests that CVM is valid, but results are often biased by poor survey design. Using a survey that was extensively pretested, we addressed

Matthew K. Udziela; Lynne L. Bennett

73

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...

74

'Pichia spartinae', A Dominant Yeast of the 'Spartina' Salt Marsh.  

National Technical Information Service (NTIS)

Pichia spartinae, a salt-marsh yeast, occurs in concentrations as great as 9 x 10 to the 7th power cells/g in intraculm cell liquid and viable tissue of the estuarine angiosperm plant, Spartina alterniflora. Highest densities of the yeast occur on the out...

S. P. Meyers D. G. Ahearn S. K. Alexander W. L. Cook

1975-01-01

75

Radium isotopes in salt marsh and estuarine environments  

SciTech Connect

Dissolved /sup 226/Ra, /sup 228/Ra, and /sup 224/Ra data from the tidal creeks and interstitial water and radium and thorium data from the sediments of salt marches in South Carolina, Delaware, and Massachusetts are presented. Dissolved radium activities in the tidal creeks were 2-3 times higher in the summer than at any other time because of increased bioturbation rates during the warm months. Radium activities in a tidal creek of the marsh surrounding North Inlet, SC, were 3 times higher than in the creeks of the Great Marsh, DE, and the Great Sippewissett Marsh, MA, primarily due to higher thorium activities in the southern marsh sediments. Diffusion out of the marsh sediments, drainage of pore water from creek banks near low tide, and bioturbation which brings high radium activity porewater and sediments toward the surface of the marsh and increases the surface area over which diffusion and desorption may occur control the dissolved radium activities in the tidal creeks.

Bollinger, M.S.

1986-01-01

76

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

77

Vulnerability of Northeastern U.S. Salt Marshes to Climatic and Anthropogenic Stressors  

EPA Science Inventory

In the Northeastern U.S., salt marsh area is in decline. Habitat change analysis has revealed fragmentation, displacement of high marsh by low marsh species, and marsh drowning, while development of adjacent uplands limits upslope migration. Using inundation experiments, field s...

78

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

79

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

2011-12-01

80

Assessing the Wildlife Habitat Value of New England Salt Marshes: I. Model and Application  

EPA Science Inventory

We developed an assessment model to quantify the wildlife habitat value of New England salt marshes based on marsh characteristics and the presence of habitat types that influence habitat use by terrestrial wildlife. Applying the model to12 salt marshes located in Narragansett B...

81

On salt marshes retreat: Experiments and modeling toppling failures induced by wind waves  

NASA Astrophysics Data System (ADS)

marshes are delicate ecosystems which are disappearing in many areas of the world, mainly due to increasing rates of sea level rise, subsidence, and anthropic pressure. The lateral erosion of the edge of salt marshes is one of the most important processes in determining changes in morphology, and wind waves have a key role in this retreat. Lateral retreat occurs by means of several types of mass failure processes, typically cantilever, sliding, and toppling. In the literature, no mechanistic models for the description of toppling failure are available. In this study, we performed a set of experiments to quantify the pressure field and the hydrodynamic forcing induced by wind waves during toppling failures of unstable blocks on a salt marsh edge. We propose a model interpreting toppling failure based on the experimental evidence as well as on the physics of the system. We model the system as a dynamic rigid block of cohesive soil, identified by the presence of a tension crack, subjected to hydrodynamic forces caused by impact of waves and resistive forces due to the block's weight and soil cohesion. The failure of the blocks occurs when the soil tensile strength is exceeded along the failure surface located at the base of the block. The model is able to reproduce failure processes observed in the laboratory. Moreover, the model reveals that the most critical conditions for marsh bank instability due to toppling failure are associated to the presence of water inside the tension crack and low water levels in front of the bank.

Bendoni, M.; Francalanci, S.; Cappietti, L.; Solari, L.

2014-03-01

82

Gross nitrous oxide production and consumption along a salt marsh redox gradient  

NASA Astrophysics Data System (ADS)

Coastal wetlands denitrify nitrate (NO3-)-rich urban and agricultural runoff, and thus decrease anthropogenic nitrogen loading on downslope aquatic ecosystems. Elevation gradients in coastal wetlands likely create redox gradients that result in a range of denitrification dynamics. Our objective was to determine if this redox gradient could elucidate the controls on nitrous oxide (N2O) production and consumption in a salt marsh bordering Tomales Bay, CA. We installed soil equilibration chambers to measure soil oxygen (O2) at 10 cm depth along a transect in each of three marsh zones: high, mid, and low (n=4 per zone). We used the stable isotope trace gas pool dilution technique to measure gross rates of N2O production and consumption over three hour sampling periods at low tide when the surface soils were not saturated. Intact soil cores (0-10 cm depth) taken from the flux chamber footprints were extracted for ammonium, NO3-, and ferric and ferrous iron (Fe(III) and Fe(II)) concentrations as well as assayed for denitrifying enzyme activity (DEA). We sampled on four dates to characterize N2O dynamics across a range of environmental conditions. Bulk soil O2 concentrations in the soil equilibration chambers were higher in the high marsh than in the mid and low marshes (p<0.001, n=44). Soil NO3- concentrations were significantly lower and HCl-extractable Fe(II) concentrations were significantly higher in the low marsh compared to the high and mid marshes (NO3- p<0.001, Fe(II) p<0.001, n=44). Despite differences in redox among the marsh zones, neither gross rates of N2O production (Figure 1a) nor consumption (Figure 1b) varied significantly among the zones. DEA also did not differ among marsh zones, with averages ranging from 136 ± 30 ng-N g-1 h-1 in the mid marsh to 550 ± 121 ng-N g-1 h-1 in the low marsh. Overall, this salt marsh was neither an N2O source nor sink, with net N2O fluxes averaging 51 ± 40 ?g-N m-2 d-1 across all marsh zones and sampling dates. However, net N2O fluxes were negative in 29 out of 44 measurements. Sub-atmospheric soil N2O concentrations at 10 cm depth together with the quantification of significant gross N2O consumption rates suggest that the net uptake of atmospheric N2O by the soil occurred in all marsh zones. Boxplots of (1) gross N2O production rates and (2) gross N2O consumption rates along a salt marsh elevation gradient. The y-axes are shown on log10 scale.

Yang, W. H.; Silver, W. L.

2012-12-01

83

Identification of metrics to monitor salt marsh integrity on National Wildlife Refuges in relation to conservation and management objectives  

USGS Publications Warehouse

Most salt marshes in the US have been degraded by human activities, and threats from physical alterations, surrounding land-use, species invasions, and global climate change persist. Salt marshes are unique and highly productive ecosystems with high intrinsic value to wildlife, and many National Wildlife Refuges (NWRs) have been established in coastal areas to protect large tracts of salt marsh and wetland-dependent species. Various management practices are employed routinely on coastal NWRs to restore and enhance marsh integrity and ensure ecosystem sustainability. Prioritizing NWR salt marshes for application of management actions and choosing among multiple management options requires scientifically-based methods for assessing marsh condition. Monitoring is integral to structured decision-making (SDM), a formal process for decomposing a decision into its essential elements. Within a natural resource context, SDM involves identifying management objectives, alternative management actions, and expected management outcomes. The core of SDM is a set of criteria for measuring system performance and evaluating management responses. Therefore, use of SDM to frame natural resource decisions leads to logical selection of monitoring attributes that are linked explicitly to management needs. We used SDM to guide selection of variables for monitoring the ecological integrity of salt marshes within the National Wildlife Refuge System (NWRS). Our objectives were to identify indicators of salt marsh integrity that are effective across large geographic regions, responsive to a wide range of threats, and feasible to implement within funding and staffing constraints of the NWRS. In April, 2008, we engaged interdisciplinary experts in a week-long rapid prototyping SDM workshop to define the essential elements of salt marsh management decisions on refuges throughout the northeastern, southwestern, and northwestern US, corresponding to respective Regions 5, 2, and 1 of the US Fish and Wildlife Service (FWS). Through this process we identified measurable attributes for monitoring salt marsh ecosystems that are integrated into conservation practice and target management objectives. The following salt marsh attributes were identified through the SDM process either for describing state condition to determine management needs or for evaluating the achievement of management objectives: historical condition and geomorphic setting; ditch density; surrounding land use; ratio of open water area to vegetation area; rate of pesticide application; environmental contaminant concentration; change in marsh surface elevation relative to sea level rise; tidal range and groundwater level; surface topography; salinity; and species composition and abundance of vegetation, invasive species, invertebrates, nekton, and breeding and wintering birds. The identified attributes were too broadly defined to serve as operational monitoring variables. Therefore, we tested specific metrics for quantifying most of these attributes in summers of 2008 and 2009. The first four attributes in the above list can be characterized by office-based analysis of existing GIS data layers. The remaining attributes require field-based methods for assessment. We were forced to exclude a small number of attributes from field tests due to inconsistent data (pesticide application rate, environmental contaminant concentrations) or requirements that exceeded the scope of this project (change in marsh surface elevation; surface topography; benthic invertebrates; wintering birds). We evaluated potential metrics for evaluating all remaining field attributes. In partnership with NWRS biologists, we tested rapid versus intensive metrics for monitoring field attributes (tidal range and groundwater level; marsh surface elevation; salinity; and species composition and abundance of vegetation, invasive species, nekton, and breeding birds) at coastal refuges throughout FWS Region 5. Seven refuges participated in metric testing in 2008: Rachel Carson (ME), Parker River (MA), Wertheim (NY), E. B. Forsythe

Neckles, Hilary A.; Guntenspergen, Glenn R.; Shriver, W. George; Danz, Nicholas P.; Wiest, Whitney A.; Nagel, Jessica L.; Olker, Jennifer H.

2013-01-01

84

Methane emissions along a salt marsh salinity gradient  

Microsoft Academic Search

The seasonal flux of methane to the atmosphere was measured at three salt marsh sites along a tidal creek. Average soil salinities at the sites ranged from 5 to 17 ppt and fluxes ranged from below detection limits (less than 0.3 mgCH4 m-2 d-1) to 259 mgCH4 m-2 d-1. Annual flux to the atmosphere was 5.6 gCH4 m-2 from the

Karen B. Bartlett; David S. Bartlett; Robert C. Harriss; Daniel I. Sebacher

1987-01-01

85

Long-term remote monitoring of salt marsh biomass  

NASA Astrophysics Data System (ADS)

An objective of NASA's Biospheric Research Program is to understand biogeochemical cycling on a global scale. Being both very biologically productive and anoxic, wetlands are major sites of carbon dioxide, mean, and sulfur gas flux on a per area basis. Biogeochemical cycling in wetlands is intricately linked to vegetation biomass production. We have been monitoring biomass dynamics of the dominant salt marsh grass Spartina alterniflora for over ten years using remote sensing. Live above ground biomass is highly correlated (r = .79) with Laridsat Thematic Mapper ('IN) and SPOT spectral data transformed into normalized difference vegetation indices. Live belowg round biomass is, in turn, highly correlated (r = .86) with live above ground biomass. Therefore, below ground biomass, a source of carbon substrates for microbial gas production, can be measured using remote sensing indirectly. These relationships have been tested over a wide latitudinal range (from Georgia to Nova Scotia). Analysis of TM and SPOT satellite images from several years has revealed substantial interannual variability in mean live aerial biomass of this species in a 580ha Delaware marsh. Additionally, interannual spatial variability in biomass distribution within the marsh is evident and seems to be linked to precipitation. The aerial biomass of high salinity areas least influenced by upland runoff is the most sensitive to precipitation, whereas marsh areas adjacent to large upland areas or freshwater creeks are the least sensitive. In summary, remote sensing is an effective tool for studying aboveground and belowground biomass in salt marshes. Once the relationship between gas flux data and vegetation biomass is better understood, satellite data could be used to estimate biomass arid gas flux over large regions of the world.

Gross, M. F.; Klemas, V.; Hardisky, M. A.

1990-12-01

86

Disturbance and recovery of salt marsh arthropod communities following BP Deepwater Horizon oil spill.  

PubMed

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. PMID:22412916

McCall, Brittany D; Pennings, Steven C

2012-01-01

87

Dual role of salt marsh retreat: Long-term loss and short-term resilience  

NASA Astrophysics Data System (ADS)

major causes of salt marsh loss are vertical drowning, when sediment accumulation on the platform cannot keep vertical pace with sea level rise, and horizontal retreat, associated with wave-induced marsh boundary erosion. Despite these processes having been extensively documented and modeled, it is unclear which loss modality dominates given a set of environmental parameters. A three-point dynamic model was developed to predict marsh loss as a function of sea level rise, allochthonous sediment supply, wind regime, tidal range, and marsh bank and mudflat erodability. Marsh horizontal and vertical evolutions were found to respond in opposing ways to wave-induced erosion processes. Marsh horizontal retreat was triggered by large mudflats, strong winds, high erodability of marsh bank and mudflat, whereas the opposite conditions acted to reduce the sediment supply to the marsh platform, promoting marsh loss to drowning. With low and moderate rates of sea level rise (˜5 mm/yr), retreat was found to be a more likely marsh loss modality than drowning. However, conditions associated with marsh retreat also increase the system resilience by transferring sediment on the marsh platform and preventing drowning. Our results suggest the use of a modular strategy for short-term marsh management: selectively protect extensive salt marsh regions by maintaining healthy vegetation on the platform, while allowing other areas to retreat, leveraging the natural resilience embedded in the lateral loss of marsh extent.

Mariotti, G.; Carr, J.

2014-04-01

88

Consequences of climate change, eutrophication, and other anthropogenic impacts to coastal salt marshes: multiple stressors reduce resiliency and sustainability  

NASA Astrophysics Data System (ADS)

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 impacts of future sea level rise combined with other anthropogenic stressors to salt marsh sustainability through the implementation of field and laboratory mesocosms, manipulative experiments, correlative studies, and predictive modeling conducted in central California and southern New England salt marshes. We report on measurements of soil respiration, decomposition, sediment accumulation, and marsh elevation, which considered jointly suggest an association between nitrate input and marsh elevation loss resulting from mineralization of soil organic matter. Furthermore, use of imaging techniques (CT scans) has shown differences in belowground root and rhizome structure associated with fertilization, resulting in a loss of sediment cohesion promoted by fine root structure. Additionally, field and greenhouse mesocosm experiments have provided insight into the specific biogeochemical processes responsible for plant mortality at high immersion or salinity levels. In conclusion, we have found that poor water quality (i.e. eutrophication) leads to enhanced respiration and decomposition of soil organic matter, which ultimately contributes to a loss of salt marsh sustainability. However, marsh deterioration studied at field sites (Jamaica Bay, NY and Elkhorn Slough, CA) is associated not only with enhanced nutrient loads, but also increased immersion due to tidal range increases resulting from dredging. To ensure the continuation of the ecosystem services provided by tidal wetlands and to develop sustainable management strategies that provide favorable outcomes under a variety of future sea level rise and land use scenarios, we need to develop a better understanding of the relative impacts of the various stressors leading to salt marsh loss. Without this understanding, costly remediation may unintentionally lead to continued marsh deterioration. More research is needed to carefully document the positive and negative aspects of nutrient loading to coastal marsh sustainability in order to ensure that coastal watersheds are managed in a way that minimizes detrimental impacts to adjacent coastal habitats, while not interfering unnecessarily with important and needed public interest activities such as agriculture and wastewater discharge.

Watson, E. B.; Wigand, C.; Nelson, J.; Davey, E.; Van Dyke, E.; Wasson, K.

2011-12-01

89

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.

90

Temperate mangrove and salt marsh sediments are a small methane and nitrous oxide source but important carbon store  

NASA Astrophysics Data System (ADS)

Tidal saline wetlands (TSW), such as mangrove and salt marsh systems, provide many valuable ecosystem services, but continue to suffer disturbance, degradation and deforestation. Tropical mangroves perform a critical role in the exchange and storage of terrestrial-marine carbon but can function as a source of methane (CH 4) and nitrous oxide (N 2O). However, little is known of biogeochemical processes in temperate mangrove and salt marsh systems in the southern hemisphere. In this study, the soil/sediment exchange of CO 2, CH 4 and N 2O was measured seasonally along a natural transition from melaleuca woodland, salt marsh and into mangroves along the Mornington Peninsula edge of Westernport Bay, Victoria, Australia. Soil/sediment physiochemical properties and sediment C density were measured concurrently. The melaleuca woodland soil was a constant CH 4 sink of approximately -25 ?g C m -2 h -1 but along the transect this rapidly switched to a weak CH 4 source (<5 ?g C m -2 h -1) in the salt marsh which increased further in the mangrove sediments where emissions of up to 375 ?g C m -2 h -1 were measured in summer. Sediment CH 4 exchange correlated with salinity, pneumatophore number and the redox potential of sediment water at depth. All three ecosystems were a small N 2O source of <10 ?g N m -2 h -1. Soil-atmosphere exchange was dominated by CO 2 which showed a significant response according to ecosystem and season along with soil temperature and salinity. Sediment C density was significantly greater in the salt marsh than the mangrove. Salt marsh sediment C density was 168 Mg C ha -1 which is comparable with that measured globally, whereas the mangrove sediment C density of 145 Mg C ha -1 is among the lowest reported. Contrary to global patterns in terrestrial soil C content and salt marsh sediment C content, data from our study indicate that mangrove sediments from a cooler, drier temperate latitude may store less C than mangroves in warmer and wetter tropical latitudes. Understanding both C storage and the greenhouse gas balance of TSWs will help us to better value these vulnerable ecosystems and manage them accordingly.

Livesley, Stephen J.; Andrusiak, Sascha M.

2012-01-01

91

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

92

Effects of warming and altered precipitation on plant and nutrient dynamics of a New England salt marsh.  

PubMed

Salt marsh structure and function, and consequently ability to support a range of species and to provide ecosystem services, may be affected by climate change. To better understand how salt marshes will respond to warming and associated shifts in precipitation, we conducted a manipulative experiment in a tidal salt marsh in Massachusetts, USA. We exposed two plant communities (one dominated by Spartina patens-Distichlis spicata and one dominated by short form Spartina alternifora) to five climate manipulations: warming via passive open-topped chambers, doubled precipitation, warming and doubled precipitation, extreme drought via rainout shelter, and ambient conditions. Modest daytime warming increased total aboveground biomass of the S. alterniflora community (24%), but not the S. patens-D. spicata community. Warming also increased maximum stem heights of S. alterniflora (8%), S. patens (8%), and D. spicata (15%). Decomposition was marginally accelerated by warming in the S. alternifora community. Drought markedly increased total biomass of the S. alterniflora community (53%) and live S. patens (69%), perhaps by alleviating waterlogging of sediments. Decomposition was accelerated by increased precipitation and slowed by drought, particularly in the S. patens-D. spicata community. Flowering phenology responded minimally to the treatments, and pore water salinity, sulfide, ammonium, and phosphate concentrations showed no treatment effects in either plant community. Our results suggest that these salt marsh communities may be resilient to modest amounts of warming and large changes in precipitation. If production increases under climate change, marshes will have a greater ability to keep pace with sea-level rise, although an increase in decomposition could offset this. As long as marshes are not inundated by flooding due to sea-level rise, increases in aboveground biomass and stem heights suggest that marshes may continue to export carbon and nutrients to coastal waters and may be able to increase their carbon storage capability by increasing plant growth under future climate conditions. PMID:19831068

Charles, Heather; Dukes, Jeffrey S

2009-10-01

93

Effects of salinity and flooding on the infectivity of salt marsh arbuscular mycorrhizal fungi in Aster tripolium L  

Microsoft Academic Search

Salt marshes are characterized by the occurrence of combined salinity and flooding stresses. The individual and combined effects of salinity and flooding on the establishment and activity of arbuscular mycorrhizal (AM) colonization in the salt marsh halophyte Aster tripolium L. by indigenous salt marsh AM fungi were evaluated. A. tripolium plants were cultivated in a mixture of sand and salt

Luís M. Carvalho; Patrícia M. Correia; Isabel Caçador; M. Amélia Martins-Loução

2003-01-01

94

Topsoil morphology indicates bio-effective redox conditions in Venice salt marshes  

NASA Astrophysics Data System (ADS)

Visual traces of iron reduction and oxidation are linked to the redox status of soils and have been used to characterise the quality of agricultural soils. We tested whether this feature could also be used to explain the spatial pattern of the natural vegetation of tidal habitats. If so, an easy assessment of the effect of rising sea level on tidal ecosystems would be possible. Our study was conducted at the salt marshes of the northern lagoon of Venice, which are strongly threatened by erosion and rising sea level and are part of the world heritage "Venice and its lagoon". We analysed the abundance of plant species at 255 sampling points along a land-sea gradient. In addition, we surveyed the redox morphology (presence/absence of red iron oxide mottles in the greyish topsoil horizons) of the soils and the presence of disturbances. We used indicator species analysis, correlation trees and multivariate regression trees to analyse relations between soil properties and plant species distribution. Plant species with known sensitivity to anaerobic conditions (e.g. Halimione portulacoides) were identified as indicators for oxic soils (showing iron oxide mottles within a greyish soil matrix). Plant species that tolerate a low redox potential (e.g. Spartina maritima) were identified as indicators for anoxic soils (greyish matrix without oxide mottles). Correlation trees and multivariate regression trees indicate the dominant role of the redox morphology of the soils in plant species distribution. In addition, the distance from the mainland and the presence of disturbances were identified as tree-splitting variables. The small-scale variation of oxygen availability plays a key role for the biodiversity of salt marsh ecosystems. Our results suggest that the redox morphology of salt marsh soils indicates the plant availability of oxygen. Thus, the consideration of this indicator may enable an understanding of the heterogeneity of biological processes in oxygen-limited systems and may be a sensitive and easy-to-use tool to assess human impacts on salt marsh ecosystems.

Lang, Friederike; von der Lippe, Moritz; Schimpel, Susanne; Scozzafava-Jaeger, Tiberio; Straub, Wolfgang

2010-03-01

95

Rhizosphere heterogeneity shapes abundance and activity of sulfur-oxidizing bacteria in vegetated salt marsh sediments  

PubMed Central

Salt marshes are highly productive ecosystems hosting an intense sulfur (S) cycle, yet little is known about S-oxidizing microorganisms in these ecosystems. Here, we studied the diversity and transcriptional activity of S-oxidizers in salt marsh sediments colonized by the plant Spartina alterniflora, and assessed variations with sediment depth and small-scale compartments within the rhizosphere. We combined next-generation amplicon sequencing of 16S rDNA and rRNA libraries with phylogenetic analyses of marker genes for two S-oxidation pathways (soxB and rdsrAB). Gene and transcript numbers of soxB and rdsrAB phylotypes were quantified simultaneously, using newly designed (RT)-qPCR assays. We identified a diverse assemblage of S-oxidizers, with Chromatiales and Thiotrichales being dominant. The detection of transcripts from S-oxidizers was mostly confined to the upper 5 cm sediments, following the expected distribution of root biomass. A common pool of species dominated by Gammaproteobacteria transcribed S-oxidation genes across roots, rhizosphere, and surrounding sediment compartments, with rdsrAB transcripts prevailing over soxB. However, the root environment fine-tuned the abundance and transcriptional activity of the S-oxidizing community. In particular, the global transcription of soxB was higher on the roots compared to mix and rhizosphere samples. Furthermore, the contribution of Epsilonproteobacteria-related S-oxidizers tended to increase on Spartina roots compared to surrounding sediments. These data shed light on the under-studied oxidative part of the sulfur cycle in salt marsh sediments and indicate small-scale heterogeneities are important factors shaping abundance and potential activity of S-oxidizers in the rhizosphere.

Thomas, Francois; Giblin, Anne E.; Cardon, Zoe G.; Sievert, Stefan M.

2014-01-01

96

Rhizosphere heterogeneity shapes abundance and activity of sulfur-oxidizing bacteria in vegetated salt marsh sediments.  

PubMed

Salt marshes are highly productive ecosystems hosting an intense sulfur (S) cycle, yet little is known about S-oxidizing microorganisms in these ecosystems. Here, we studied the diversity and transcriptional activity of S-oxidizers in salt marsh sediments colonized by the plant Spartina alterniflora, and assessed variations with sediment depth and small-scale compartments within the rhizosphere. We combined next-generation amplicon sequencing of 16S rDNA and rRNA libraries with phylogenetic analyses of marker genes for two S-oxidation pathways (soxB and rdsrAB). Gene and transcript numbers of soxB and rdsrAB phylotypes were quantified simultaneously, using newly designed (RT)-qPCR assays. We identified a diverse assemblage of S-oxidizers, with Chromatiales and Thiotrichales being dominant. The detection of transcripts from S-oxidizers was mostly confined to the upper 5 cm sediments, following the expected distribution of root biomass. A common pool of species dominated by Gammaproteobacteria transcribed S-oxidation genes across roots, rhizosphere, and surrounding sediment compartments, with rdsrAB transcripts prevailing over soxB. However, the root environment fine-tuned the abundance and transcriptional activity of the S-oxidizing community. In particular, the global transcription of soxB was higher on the roots compared to mix and rhizosphere samples. Furthermore, the contribution of Epsilonproteobacteria-related S-oxidizers tended to increase on Spartina roots compared to surrounding sediments. These data shed light on the under-studied oxidative part of the sulfur cycle in salt marsh sediments and indicate small-scale heterogeneities are important factors shaping abundance and potential activity of S-oxidizers in the rhizosphere. PMID:25009538

Thomas, François; Giblin, Anne E; Cardon, Zoe G; Sievert, Stefan M

2014-01-01

97

Microbial Aldicarb Transformation in Aquifer, Lake, and Salt Marsh Sediments  

PubMed Central

The microbial transformation of [N-methyl-(sup14)C]aldicarb, a carbamate pesticide, occurred in aquifer, lake, and salt marsh sediments. Microbial degradation of aldicarb took place within 21 days in aquifer sediments from sites previously exposed to aldicarb (Jamesport, Long Island, N.Y.) but did not occur in sediments which were not previously exposed (Connetquot State Park, Long Island, N.Y.). At the Jamesport sites, higher aldicarb transformation rates occurred in deep, anoxic sediments than in shallow, oxic sediments. There was a significant negative relationship (P < 0.05) between transformation rates and ambient dissolved O(inf2) levels. Aldicarb hydrolysis rates in Jamesport sediments were 10- to 1,000-fold lower than rates previously reported for soils. In addition, aldicarb degradation rates were not significantly correlated with measurements of bacterial activity and density previously determined in the same sediments. Substantially higher aldicarb degradation rates were found in anoxic lake and salt marsh than in aquifer sediments. Furthermore, we investigated the anaerobic microbial processes involved in aldicarb transformation by adding organic substrates (acetate, glucose), an alternative electron acceptor (nitrate), and microbial inhibitors (molybdate, 2-bromoethanesulfonic acid) to anoxic aquifer, lake, and salt marsh sediments. The results suggest that a methanogenic consortium was important in aldicarb transformation or in the use of aldicarb-derived products such as methylamine. In addition, microbial aldicarb transformation proceeded via different pathways under oxic and anoxic conditions. In the presence of O(inf2), aldicarb transformation was mainly via an oxidation pathway, while in the absence of O(inf2), degradation took place through a hydrolytic pathway (including the formation of methylamine precursors). Under anoxic conditions, therefore, aldicarb can be transformed by microbial consortia to yield products which can be of direct benefit to natural populations of methanogens present in sediments.

Kazumi, J.; Capone, D. G.

1995-01-01

98

Loss of 'Blue Carbon' from Coastal Salt Marshes Following Habitat Disturbance  

PubMed Central

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 m2 mean area ± SE) of vegetation loss (aged 3-12 months) in a salt marsh meadow the size of a soccer field (7 275 m2). 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.

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

2013-01-01

99

Deuterium in water vapor evaporated from a coastal salt marsh  

NASA Astrophysics Data System (ADS)

Atmospheric water vapor was sampled simultaneously at two heights in the atmospheric surface layer above a coastal salt marsh near New Haven, Connecticut, during June 11-27, 1997. The water vapor samples were analyzed for their mixing ratio, Q, and deuterium isotope ratio, ?D. The observed ?D varied in the range of -145 to -89 per mil and was positively correlated with Q, reflecting the influence of in-cloud condensation and surface evapotranspiration processes at a regional scale. Both Q and ?D were, in general, lower at the upper level, indicating an upward transport of H216O and HD16O. The Craig-Gordon model reproduced reasonably well the combined effects of equilibrium and kinetic fractionations and atmospheric demand on the evaporation process. Transpiration of the marsh plants, Spartina patens (Ait.), was a minor component (11%) of the total evapotranspiration during the experimental period. We also suggest that the relationship between ?D and salinity, S, of the marsh surface water can be used to infer the isotope flux ratio. More data, however, are needed to verify this mass balance approach.

He, Hui; Lee, Xuhui; Smith, Ronald B.

2001-06-01

100

Candidate Tsunami Deposits at Carpinteria Salt Marsh, Southern California  

NASA Astrophysics Data System (ADS)

Carpinteria Salt Marsh, 15 km southeast of Santa Barbara, California preserves geologic evidence of possible past tsunami inundation along the southern California coast. The proximity of the Santa Barbara coastline to the Goleta slide complex and to numerous offshore faults in the Santa Barbara basin suggests a potential for moderate to large tsunamis. A field investigation in February 2008 collected more than 60 cores and examined 8 cutbank exposures throughout the marsh. Sand layers consistent with tsunami deposition were found at depths from 35 to 96 cm in cores from four areas within the marsh. The sand layers, which range from 1 cm to 35 cm thick and extend up to 630 m inland, had sharp lower contacts and were often normally graded. In addition, in some cores there were one or more intervening mud layers within the sand layer. Composition and angularity of the sand is similar to sands found in the surrounding beach, dune, and nearshore environments. While the sand layers occur at similar depths in the cores, they were concentrated in four areas that were isolated by regions with no evidence of tsunami deposition. The deposits may represent spatially discontinuous deposition from one event, spatially continuous deposition from one event with poor preservation of the deposits, or deposition from more than one event. Discontinuous deposition from one event is in contrast to spatially continuous sheet deposition characteristic of moderate to large tsunamis, but may represent isolated deposition by a smaller tsunami along channel banks. The deposit is more consistent with tsunami deposition than deposition by other event-driven processes such as storms or floods. However, marsh processes that may create normally graded sand layers such as channel migration must also be considered before accepting a tsunami origin for the deposits.

Peters, R.; Jaffe, B. E.; Buckley, M.; Watt, S. G.

2008-12-01

101

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

102

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-...

103

Recovery of a northern New England salt marsh plant community from winter icing  

Microsoft Academic Search

High latitude salt marsh plant communities are frequently exposed to conspicuous winter ice disturbances, which trigger secondary succession. In this paper, we document the recovery of a northern New England salt marsh from a severe winter icing event in 1998. Ice disturbances that killed plants but that left the underlying peat intact recovered rapidly. However, ice damage that killed plants

Patrick J. Ewanchuk; Mark D. Bertness

2003-01-01

104

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...

105

New England salt marsh pools: A quantitative analysis of geomorphic and geographic features  

USGS Publications Warehouse

New England salt marsh pools provide important wildlife habitat and are the object of on-going salt marsh restoration projects; however, they have not been quantified in terms of their basic geomorphic and geographic traits. An examination of 32 ditched and unditched salt marshes from the Connecticut shore of Long Island Sound to southern Maine, USA, revealed that pools from ditched and unditched marshes had similar average sizes of about 200 m2, averaged 29 cm in depth, and were located about 11 m from the nearest tidal flow. Unditched marshes had 3 times the density (13 pools/ha), 2.5 times the pool coverage (83 m pool/km transect), and 4 times the total pool surface area per hectare (913 m2 pool/ha salt marsh) of ditched sites. Linear regression analysis demonstrated that an increasing density of ditches (m ditch/ha salt marsh) was negatively correlated with pool density and total pool surface area per hectare. Creek density was positively correlated with these variables. Thus, it was not the mere presence of drainage channels that were associated with low numbers of pools, but their type (ditch versus creek) and abundance. Tidal range was not correlated with pool density or total pool surface area, while marsh latitude had only a weak relationship to total pool surface area per hectare. Pools should be incorporated into salt marsh restoration planning, and the parameters quantified here may be used as initial design targets.

Adamowicz, S.C.; Roman, C.T.

2005-01-01

106

Salt Marsh Sediment Mixing Following Petroleum Hydrocarbon Exposure from the Deepwater Horizon Oil Spill  

NASA Astrophysics Data System (ADS)

Tidal marshes support valuable ecosystems, but their coastal locations make them susceptible to oil spills. Oil spilled in the ocean is easily transported via tidal and wind-driven currents to the shore and incorporated into sediments. The primary goal of this research was to determine how deeply oil from the 2010 Deepwater Horizon spill has penetrated sediments along the Gulf Coast, and whether oil has quantifiably affected benthic ecosystems at these sites. Sediment cores were taken from three marsh environments at sites classified as unoiled, lightly oiled, and heavily oiled based on data from NOAA's Environmental Response Management Application (ERMA). These classifications have been verified by measurements of total polycyclic aromatic hydrocarbons ([TPAH] without perylene). Bioturbators, such as polychaetes and oligochaetes, constantly rework sediments as they burrow into them. In this way, bioturbators can play a role in the fate of organic contaminants, either by allowing for natural remediation of contaminants via enhanced microbial degradation, or by mixing oil from the surface deeper into the sediment column. The constant fallout radionuclide 7Be was measured to determine short-term sediment mixing depths. However, there was a conspicuous absence of 7Be at most sites. This could be due to sediment composition constraints on 7Be sorption (coarse-grained sediment, high organic matter contents), or rapid erosion of the marsh surface. Instead, minimum mixing depths were derived from 234Thxs profiles. Thorium-234 is a lithogenic isotope that has widely been used to trace particle mixing on short time scales near that of its mean life (36 days). Penetration depths of 234Thxs ranged between 0.25 and 4.5 cm. Sediment accumulation rates will be determined using 210Pb, with verification from an independent tracer, 137Cs, in selected cores. Preliminary results from 210Pb profiles reveal thorough, long-term (decadal) sediment mixing to at least 40 cm at all sites. Salt marsh sediments of Bay Jimmy, Louisiana were significantly impacted by the DWH oil spill, as indicated by TPAH concentrations up to 18,279 ppb. This is not only well above what is considered to be the upper limit background for this area (1,500 ppb), but also far exceeds the level at which adverse biological effects occur (Effects Range-Low = 4,022 ppb). In addition, benthic foraminifera responded to the heavy oiling at Bay Jimmy by decreases to both standing stock and depth of habitation relative to unoiled sites. Deformed specimens were also found at this site. These data clearly show that oil can be quickly incorporated into salt marsh sediments via mixing, with demonstrable impacts on indigenous benthos.

Hatch, R. S.; Yeager, K. M.; Brunner, C. A.; Wade, T. L.; Briggs, K. B.; Schindler, K. J.

2013-12-01

107

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

108

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

109

Silica uptake by Spartina--evidence of multiple modes of accumulation from salt marshes around the world  

PubMed Central

Silicon (Si) plays a critical role in plant functional ecology, protecting plants from multiple environmental stressors. While all terrestrial plants contain some Si, wetland grasses are frequently found to have the highest concentrations, although the mechanisms driving Si accumulation in wetland grasses remain in large part uncertain. For example, active Si accumulation is often assumed to be responsible for elevated Si concentrations found in wetland grasses. However, life stage and differences in Si availability in the surrounding environment also appear to be important variables controlling the Si concentrations of wetland grasses. Here we used original data from five North American salt marshes, as well as all known published literature values, to examine the primary drivers of Si accumulation in Spartina, a genus of prolific salt marsh grasses found worldwide. We found evidence of multiple modes of Si accumulation in Spartina, with passive accumulation observed in non-degraded marshes where Spartina was native, while rejective accumulation was found in regions where Spartina was invasive. Evidence of active accumulation was found in only one marsh where Spartina was native, but was also subjected to nutrient over-enrichment. We developed a conceptual model which hypothesizes that the mode of Si uptake by Spartina is dependent on local environmental factors and genetic origin, supporting the idea that plant species should be placed along a spectrum of Si accumulation. We hypothesize that Spartina exhibits previously unrecognized phenotypic plasticity with regard to Si accumulation, allowing these plants to respond to changes in marsh condition. These results provide new insight regarding how salt marsh ecosystems regulate Si exchange at the land-sea interface.

Carey, Joanna C.; Fulweiler, Robinson W.

2014-01-01

110

A Dynamic Nutrient Budget of Subsystem Interactions in a Salt Marsh Estuary  

NASA Astrophysics Data System (ADS)

In tidal salt marsh estuaries, the different habitats of the ecosystem interact primarily through the tidal creek water column. These interactions include nutrient and materials exchanges with the salt marsh, oyster reefs, creek bottoms, and adjacent uplands. Nutrient budgets are often used to synthesize these kinds of subsystem exchange data, and are usually based on annual totals without accounting for nutrient variability at finer temporal resolutions. In this paper, we present a dynamic budget of carbon (C), nitrogen (N), and phosphorus (P) for the North Inlet estuary, South Carolina that synthesizes subsystem flux data in a new way. We have developed a dynamic budget that uses a tidal hydrology model to generate daily areas of inundated intertidal habitat (i.e. vegetated marsh and oyster reef) from tidal heights calculated hourly and combines them with flux data to determine a net daily input to, or removal from, the water column. Daily surpluses or deficits of each nutrient were compared with daily rates of change in observed tidally-averaged nutrient concentrations. Particular emphasis was placed on evaluating budget output from the intertidal subsystems. We compared our total annual budgets to values from syntheses of two North Inlet flux studies. Although areas of marsh inundated were 150-200 times greater than areas of oyster reef inundated, interactions per unit volume of estuarine water column were comparable in magnitude for soluble reactive P (SRP), particulate organic C (POC), and dissolved organic C (DOC). The marsh dominated the ammonium (NH +4) and nitrate + nitrite (NN) exchanges in the summer but the NH +4 and POC output were particularly sensitive to changes in oyster reef area. Winter and spring DOC release by the marsh coincided closely (in timing and magnitude) with the peak in DOC concentrations observed in the North Inlet estuary, suggesting that forest stream inputs of DOC are not nearly as important as has been hypothesized. Comparison of our budget predictions to a previous synthesis of the same subsytem flux data confirmed the power of using tidal hydrology to estimate subsystem interactions between sampling times. These comparisons also emphasized the importance of (1) water column processes to NH +4 dynamics (2) subtidal benthic fluxes to DOC dynamics, and (3) external inputs to NN dynamics. By incorporating our best current knowledge of estuary-wide subsystem areas, the dynamic budget also allowed us to link subsystem flux data to the results of a study quantifying exchanges between the estuary and the coastal ocean. That comparison indicated the shortcomings of any site-specific extrapolation to whole-system conclusions where a homogeneous ecosystem must be assumed. We used the differences between our total annual C, N, and P budgets and reported exports of those constituents from the system to generate hypotheses and suggest future research efforts both at North Inlet and southeastern salt marsh estuaries in general.

Childers, Daniel L.; McKellar, Henry N.; Dame, Richard F.; Sklar, Fred H.; Blood, Elizabeth R.

1993-02-01

111

Habitat Characteristics and Eggshell Distribution of the Salt Marsh Mosquito, Aedes vigilax, in Marshes in Subtropical Eastern Australia  

PubMed Central

Research at 10 locations in coastal subtropical Queensland, Australia, has shown that salt marshes contained heterogeneous distributions of eggshells of the pest and vector mosquito Aedes vigilax (Skuse) (Diptera:Culicidae). The eggshell distribution was related to specific vegetation assemblages, with a mix of the grass, Sporobolus virginicus (L.) Kunth (Poales: Poaceae), and the beaded glasswort, Sarcocornia quinqueflora (Bunge ex (Ung.-Stern) A.J. Scott (Caryophyllales: Chenopodiaceae), as significantly higher in eggshells than any other vegetation. There were also high numbers in the mix of S. virginicus with the arrowgrass, Triglochin striata Ruiz & Pavón (Alismatales: Juncaginaceae). Both mixed types are found in relatively wetter areas, despite very few eggshells being found generally in the low marsh. Most sites contained S. virginicus and eggshell locations were variable for this species alone. This was probably related to its life form variability in response to salinity and location on the marsh. Location on the marsh was important for eggshell distribution with most eggshells around the edges of pools and depressions, followed by, but to a significantly lesser extent, the marsh surface. Eggshells were fewest in the low marsh. Partition analysis resulted in a tree that simplified and summarised the factors important for eggshell distribution confirming the individual analyses. The potential effects of climate, sea level and other change are also briefly discussed in the context of likely changes to land cover and relative location on the marsh. For example, increased sea level may lead to low marsh conditions extending into higher marsh area with implications for oviposition and numbers of eggshells.

Dale, Pat E. R.; Knight, Jon; Kay, Brian H.; Chapman, Heather; Ritchie, Scott A.; Brown, Michael D.

2008-01-01

112

Lignocellulose-responsive bacteria in a southern California salt marsh identified by stable isotope probing  

PubMed Central

Carbon cycling by microbes has been recognized as the main mechanism of organic matter decomposition and export in coastal wetlands, yet very little is known about the functional diversity of specific groups of decomposers (e.g., bacteria) in salt marsh benthic trophic structure. Indeed, salt marsh sediment bacteria remain largely in a black box in terms of their diversity and functional roles within salt marsh benthic food web pathways. We used DNA stable isotope probing (SIP) utilizing 13C-labeled lignocellulose as a proxy to evaluate the fate of macrophyte-derived carbon in benthic salt marsh bacterial communities. Overall, 146 bacterial species were detected using SIP, of which only 12 lineages were shared between enriched and non-enriched communities. Abundant groups from the 13C-labeled community included Desulfosarcina, Spirochaeta, and Kangiella. This study is the first to use heavy-labeled lignocellulose to identify bacteria responsible for macrophyte carbon utilization in salt marsh sediments and will allow future studies to target specific lineages to elucidate their role in salt marsh carbon cycling and ultimately aid our understanding of the potential of salt marshes to store carbon.

Darjany, Lindsay E.; Whitcraft, Christine R.; Dillon, Jesse G.

2014-01-01

113

Evidence for iron-sulfate coupling in salt marsh sediments  

NASA Astrophysics Data System (ADS)

Organic carbon burial in shallow marine sediments represents an important net sink in the global carbon cycle. Microbially mediated oxidation of organic matter in oxic, suboxic, and anoxic sediments however, prevents the ultimate burial of organic carbon and its removal from the surface of the planet. Although the subsurface transformations of organic carbon have been studied extensively, an enigmatic question remains: when organic matter is deposited, what determines whether it will be buried, reoxidized, or undergo methanogenesis? One hypothesis is that the sulfur cycle, due to the abundance of sulfate in many surface environments, dominates the subsurface oxidation or other fate of organic carbon. However, it has also been suggested that iron may in turn play a key role in determining the behavior of the sulfur cycle. To better understand the controls on these processes, we are using stable isotope and geochemical techniques to explore the microbially mediated oxidation of organic carbon in salt marsh sediments in North Norfolk, UK. In these sediments there is a high supply of organic carbon, iron, and sulfate (from diurnal tidal cycles). Thus these environments may provide insight into the nature of interactions between the carbon, iron, and sulfur cycles. A series of sampling missions was undertaken in the autumn and winter of 2013-2014. In subsurface fluid samples we observe very high ferrous iron concentrations (>1mM), indicative of extended regions of iron reduction (to over 30cm depth). Within these zones of iron reduction we would predict no sulfate reduction, and as expected ?34Ssulfate remains unchanged with depth. However, ?18Osulfate exhibits significant enrichments of up to 5 permil. This decoupling in the sulfur and oxygen isotopes of sulfate is suggestive of a sulfate recycling process in which sulfate is reduced to an intermediate sulfur species and subsequently reoxidized to sulfate. Taken together, these data suggest that microbial assemblages in these salt marsh sediments facilitate a cryptic cycling of sulfur, potentially mediated by iron species in the zone of iron reduction.

Mills, Jennifer; Antler, Gilad; Turchyn, Alexandra

2014-05-01

114

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

115

Salt Marsh Sediment Biogeochemical Response to the Deep Water Horizon BP Oil Spill (Skiff Island, LA, and Cat Island, Marsh Point, and Salt Pan Island, MS)  

NASA Astrophysics Data System (ADS)

The large scale impact of the Deep Water Horizon BP Oil Spill on biological communities can be better predicted by developing an understanding of how carbon loading from the spill is affecting the microbial and biological communities of salt marshes along the Mississippi and Louisiana Gulf Coast. Sediment biogeochemical processes that degrade enriched carbon pools through sulfate reduction are primarily responsible for the biological breakdown of spilled hydrocarbons (Shin et al., 2000). Determination of sulfide concentration in contaminated areas, therefore, allows for an assessment of the oil spill impact on salt marsh at Skiff Island, LA, and Marsh Point, Cat Island, and Salt Pan Island, MS. As a result of carbon loading, porewater hydrogen sulfide (H2S) concentrations are expected to show an increase in the largely anoxic wetland sediment, making the sediment more toxic and inhospitable to marsh vegetation (Alber et al., 2008). High sulfide levels due to carbon loading in hydrocarbon contaminated salt marshes cause microbial activity to increase at the plant rhizospere, leading to plant browning and die back (Eldridge and Morse 2000). Preliminary analysis of the Marsh Point study area was conducted in Fall 2010. Sediment cores indicated that sulfate reducing bacteria are significantly more active in contaminated sediments, producing sulfide concentrations 20x higher than in non-contaminated sediments. The difference in the sediment biogeochemistry between the contaminated site and non-contaminated site at Marsh Point, MS indicated that the effects of hydrocarbon contamination on sulfur cycling in salt marshes should be more spatially explored. In Fall 2011, the study was expanded to include Skiff Island, LA, and Cat Island, and Salt Pan Island, MS in addition to Marsh Point, MS. Sediment electrode profiles (H2S, O2, pH, and Eh), degree of hydrocarbon contamination (GC), grain size analysis, microbial community substrate level carbon utilization profiles, and total organic carbon results will be presented on these four locations in order to explore the potential sedimentary geochemical processes impacting salt marsh dieback, which may be enhanced as a result of the Deep Water Horizon BP Oil Spill.

Guthrie, C. L.; McNeal, K. S.; Mishra, D. R.; Blakeney, G. A.

2012-12-01

116

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

117

Population differentiation in the life-history characteristics of salt-marsh annuals  

Microsoft Academic Search

Coastal salt marshes are heterogeneous spatially but predictable temporally. Genetic differentiation between populations on different parts of a marsh in response to this combination of circumstances has been well documented in several perennial species; differentiation has been evident in certain features of the life cycle that contribute to overall fitness.

A. J. Davy; H. Smith

1985-01-01

118

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...

119

The ecology of temperate salt-marsh fucoids. I. Occurrence and distribution of Ascophyllum nodosum ecads  

Microsoft Academic Search

The distribution of several free-living Ascophyllum nodosum ecads, including scorpioides and mackaii, in a temperate salt marsh is described. Morphological characterization of these ecads by the presence or absence of air bladders and reproductive receptacles, and size and shape of fronds, indicated that several free-living forms occur throughout the marsh. Plants resembling the ecad mackaii were more closely associated with

B. H. Brinkhuis

1976-01-01

120

EFFECTS OF MALATHION ON MICROORGANISMS OF AN ARTIFICIAL SALT-MARSH ENVIRONMENT  

EPA Science Inventory

Laboratory salt-marsh environments were treated with malathion, an organophosphate insectide, and aerobic heterotrophic bacteria were monitored to determine changes in their microbial ecology. Several physiological activities were assayed in both treated and untreated controls; h...

121

Distribution of Larval Tabanidae (Diptera) in a 'Spartina alterniflora' Salt Marsh.  

National Technical Information Service (NTIS)

Larvae of Chrysops fuliginosus Wiedemann and Tabanus nigrovittatus Macquart were recovered from the soil of a regularly flooded salt marsh having Spartina alterniflora Loisel (smooth cordgrass) as the dominant vegetation. The larvae were found throughout ...

J. C. Dukes T. D. Edwards R. C. Axtell

1974-01-01

122

DISTRIBUTION OF LARVAL TABANIDAE (DIPTERA) IN A SPAR TINA ALTERNIFLORA SALT MARSH  

Microsoft Academic Search

Larvae of Chrysopsfuliginosus Wiedemann and Tabanus nigrovittatus Macquart were recovered from the soil of a regularly flooded salt marsh having Spartina altemifloraLoisel (smooth cordgrass) as the dominant vegetation. The larvae were

J. C. Dukes; T. D. Edwards; R. C. Axtell

123

Associations of Tabanidae (Diptera) Larvae with Plant Species in Salt Marshes, Carteret County, North Carolina.  

National Technical Information Service (NTIS)

Larvae of Tabanus nigrovittatus Macquart, Chrysops fuliginosus Wiedemann and C. atlanticus Pechuman were recovered most often and in greatest abundance in regularly flooded areas of salt marshes with nearly uniform stands of Spartina alterniflora Loisel (...

J. C. Dukes T. D. Edwards R. C. Axtell

1973-01-01

124

Physiological Ecology of Acetylene Reduction (Nitrogen Fixation) in a Delaware Salt Marsh.  

National Technical Information Service (NTIS)

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 con...

H. J. Dicker D. W. Smith

1980-01-01

125

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...

126

Two New Murals by John Biggers: Salt Marsh and Nubia, Origins of Business and Commerce.  

ERIC Educational Resources Information Center

Provides background information on the life and career of muralist John Biggers. Focuses on two of his murals, offering a description and information about each: (1) "Salt Marsh;" and (2) "Nubia, the Origins of Business and Commerce." (CMK)

Theisen, Olive Jensen

2001-01-01

127

Effects of pipeline construction on the vegetation and macrofauna of two South Carolina, USA salt marshes  

Microsoft Academic Search

We examined the recovery of vegetation and salt marsh macrofauna in a pipeline construction corridor at two locations where\\u000a it intersected intertidal salt marshes near Charleston, SC. The impacts of construction were evaluated prior to construction\\u000a and for subsequent periods of 34 and 46 months at the two sites using aerial photography and three field sampling methods.\\u000a Quadrats were used

David M. Knott; Elizabeth L. Wenner; Priscilla H. Wendt

1997-01-01

128

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

Microsoft Academic Search

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

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

2011-01-01

129

Mineralization of detrital lignocelluloses by salt marsh sediment microflora.  

PubMed

Specifically radiolabeled C-(cellulose)-lignocellulose and C-(lignin)-lignocellulose were isolated from labeled cuttings of Spartina alterniflora (cordgrass) and Pinus elliottii (slash pine). These were used to estimate the rates of mineralization to CO(2) of lignocelluloses of estuarine and terrestrial origin in salt marsh estuarine sediments. The lignin moiety of pine lignocellulose was mineralized 10 to 14 times more slowly than that of Spartina lignocellulose, depending on the source of inoculum. Average values for percent mineralization after 835 h of incubation were 1.4 and 13.9%, respectively. For Spartina lignocellulose, mineralization of the cellulose moiety was three times faster than that of the lignin moiety. Average values for percent mineralization after 720 h of incubation were 32.1 and 10.6%, respectively. Lignocellulose and lignin contents of live pine and Spartina plants were analyzed and found to be 60.7 and 20.9%, respectively, for pine and 75.6 and 15.1%, respectively, for Spartina. PMID:16345647

Maccubbin, A E; Hodson, R E

1980-10-01

130

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

131

Hydrodynamic modeling for river delta salt marshes using lidar topography  

NASA Astrophysics Data System (ADS)

Topographic data from lidar and multi-beam sonar create new challenges for hydrodynamic models of estuaries, tidelands, and river deltas. We now can readily obtain detailed elevation data on 1 m scales and finer, but solving hydrodynamics with model grid cells at these small scales remains computationally prohibitive (primarily because of the small time step required for small grid cells). Practical estuarine models for the next decade or so will likely have grid scales in the range of 5 to 15 m. So how should we handle known subgrid-scale features? Simply throwing out known data does not seem like a good idea, but there is no consensus on how best to incorporate knowledge of subgrid topography into either hydrodynamic or turbulence models. This presentation discusses both the theoretical foundations for modeling subgrid-scale features and the challenges in applying these ideas in the salt marshes of a river delta. The subgrid problem highlights some important areas for field and laboratory research to provide calibration parameters for new models that upscale the effects of known subgrid features.

Hodges, Ben R.

2014-05-01

132

Estimating evapotranspiration for a temperate salt marsh, Newcastle, Australia  

NASA Astrophysics Data System (ADS)

Evapotranspiration was studied at a salt marsh site in the Hunter River estuary, NSW, Australia, during 1996-8. Estimates of actual evapotranspiration (Ea) were obtained for three sites using the eddy correlation method. These values were compared with results obtained with the Penman and Penman-Monteith equations, and with pan evaporation. The Penman-Monteith method was found to be most reliable in estimating daily and hourly evapotranspiration. Surface resistance values averaging 12 s m-1 were derived from the eddy correlation estimates. Recent tidal flooding and rainfall were found to decrease surface resistance and increase Ea/Ep ratios. Estimates of evapotranspiration obtained using the Penman-Monteith method were shown to be sensitive to changes in surface resistance, canopy height and the method used to estimate net radiation from incoming solar radiation. These results underline the importance of accurately estimating such parameters based on site-specific data rather than relying on empirical equations, which are derived primarily for crops and forests.

Hughes, C. E.; Kalma, J. D.; Binning, P.; Willgoose, G. R.; Vertzonis, M.

2001-04-01

133

Remote sensing of biomass and annual net aerial primary productivity of a salt marsh  

NASA Technical Reports Server (NTRS)

Net aerial primary productivity is the rate of storage of organic matter in above-ground plant issues exceeding the respiratory use by the plants during the period of measurement. It is pointed out that this plant tissue represents the fixed carbon available for transfer to and consumption by the heterotrophic organisms in a salt marsh or the estuary. One method of estimating annual net aerial primary productivity (NAPP) required multiple harvesting of the marsh vegetation. A rapid nondestructive remote sensing technique for estimating biomass and NAPP would, therefore, be a significant asset. The present investigation was designed to employ simple regression models, equating spectral radiance indices with Spartina alterniflora biomass to nondestructively estimate salt marsh biomass. The results of the study showed that the considered approach can be successfully used to estimate salt marsh biomass.

Hardisky, M. A.; Klemas, V.; Daiber, F. C.; Roman, C. T.

1984-01-01

134

Diagenesis of organic matter in georgia salt marshes  

NASA Astrophysics Data System (ADS)

Organic matter preserved in sediments of Georgia salt marshes derives from Spartina alterniflora and planktonic and bacterial substances. Sources and diagenesis of sedimentary organic material were studied by means of stable C and N isotopes and gas chromatography of pyrolysates from plants, suspended sediments, and a series of muds (modern to 1400 years old) from St Catherines Island, Georgia. Suspended particulate matter ( > 20 ?m) has isotopic compositions (? 13C = -18 to -22), which are composed of an average 34-42% plankton carbon and 58-65% higher plant detritus, as determined by isotopic mass balance of the system. The ? 13C of bulk sediments and humic acids (? 13C = -18 to -19) extracted from them remain relatively constant over time. The ? 13C of acid hydrolysates, however, changed from - 15‰ in surface marsh sediment to a ? 13C of -19 from sediment sampled at a depth of 125 cm. Higher-plant normal-hydrocarbons are present in muds and in particulate matter from the water column, and ? 13C in lipids and gas chromatography of pyrolysates of samples reflect this addition. With increasing age, ? 15N of total sediments and acid hydrolysates increases, and the ratio of odd-to-even hydrocarbons in the pyrolysates decreases. Initially, low density material in sediments consists primarily of plant fragments. With time, this material is decayed and diluted by microbial material, changes that are reflected by more negative ? 13C of -15 to -17·5, as compared to ? 13C of -12 for moden Spartina, and the addition of n-alkanes in the range of C 13-19. The isotopic heterogeneity in surface sediments with carbon as an example, ranged from a ? 13C of -15 (plant fragments) to -22 (sediment following lipid, humic acid, and plant fragment extraction). Nowhere was the C isotopic composition of total Spartina expressed even though microscopic plant pieces, lignocellulose pyrolysis fragments, and n-alkanes from C 22-27 were detected in suspended particulate matter, total sediments, and humic acids.

Fogel, Marilyn L.; Kent Sprague, E.; Gize, Andrew P.; Frey, Robert W.

1989-02-01

135

Hydrogeochemical zonation in intertidal salt marsh sediments: evidence of positive plant-soil feedback?  

NASA Astrophysics Data System (ADS)

Surface and subsurface environments are linked by the biogeochemical activity in near-surface sediment and by the hydrological fluxes that mobilize its reagents and products. A particularly dynamic and interesting setting to study near-surface hydrogeochemistry is the intertidal zone. Here, the very strong tidal hydraulic forcing is often thought to dominate water and solute transport. However, we demonstrated the importance of two additional subsurface drivers: groundwater flow and plant root water uptake. A high-resolution, coupled surface water-groundwater model of an intertidal salt marsh in San Francisco Bay, CA showed that these three drivers vary over different spatial scales: tidal flooding varies over 10's of meters; groundwater flow varies over meters, particularly within channel banks; and plant root water uptake varies in 3D at the sub-meter scale. Expanding on this third driver, we investigated whether the spatial variations in soil-water-plant hydraulic interactions that occur due to vegetation zonation also cause distinct geochemical zonation in salt marsh sediment pore waters. The existence of such geochemical zonation was verified and mapped by detailed field observations of the chemical composition of sediments, pore waters, surface waters, and vegetation. The field data and the coupled hydrologic model were then further analyzed to evaluate potential causal mechanisms for the geochemical zonation, including testing the hypothesis that the vegetation affects pore water geochemistry via a positive feedback beneficial to itself. If further supported by future studies, this geochemical feedback may complement known physical ecosystem engineering mechanisms to help stabilize and organize intertidal wetlands.

Moffett, K. B.; Dittmar, J.; Seyfferth, A.; Fendorf, S.; Gorelick, S.

2012-12-01

136

Associations of Tabanidae (Diptera) Larvae with Plant Species in Salt Marshes, Carteret County, North Carolina1  

Microsoft Academic Search

Larvae of Tabanus nigrovittatus Macquart, Chrysops fuliginosus Wiedemann and C. atlanticus Pechuman were recovered most often and in greatest abundance in regularly flooded areas of salt marshes with nearly uniform stands of Spartina alterniflora Loisel (smooth cordgrass). Areas of S. cynosuroides (L.) Roth. (giant cordgrass), Distichlis spicata (L.) Greene (salt grass), and funcus roemerianus Scheele (black needle rush) yielded decreasing

J. C. DUKES; T. D. EDWARDS; R. C. AXTELL

137

Biostimulation for the Treatment of an oil-contaminated Coastal Salt Marsh  

Microsoft Academic Search

A field study was conducted on a coastal salt marsh in Nova Scotia, Canada, during the summer of 2000. The objective of the\\u000a study was to assess the effectiveness of biostimulation in restoring an oil-contaminated coastal marsh dominated by Spartina alterniflora under north-temperate conditions. Three remediation treatments were tested with two additional unoiled treatments, with and\\u000a without added nutrients, serving

Susana Garcia-Blanco; Albert D. Venosa; Makram T. Suidan; Kenneth Lee; Susan Cobanli; John R. Haines

2007-01-01

138

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

139

Hypoxic coma as a strategy to survive inundation in a salt-marsh inhabiting spider  

PubMed Central

Spiders constitute a major arthropod group in regularly inundated habitats. Some species survive a flooding period under water. We compared survival during both submersion and a recovery period after submersion, in three stenotopic lycosids: two salt-marsh species Arctosa fulvolineata and Pardosa purbeckensis, and a forest spider Pardosa lugubris. Both activity and survival rates were determined under controlled laboratory conditions by individually surveying 120 females kept submerged in sea water. We found significant differences between the three species, with the two salt-marsh spiders exhibiting higher survival abilities. To our knowledge, this study reports for the first time the existence of a hypoxic coma caused by submersion, which is most pronounced in A. fulvolineata, the salt-marsh spider known to overcome tidal inundation under water. Its ability to fall into that coma can therefore be considered a physiological adaptation to its regularly inundated habitat.

Petillon, Julien; Montaigne, William; Renault, David

2009-01-01

140

Effects of several salt marsh plants on mouse spleen and thymus cell proliferation using mtt assay  

NASA Astrophysics Data System (ADS)

In the present study, we have tested the effects of 21 salt marsh plants on cell proliferation of mouse immune cells (spleen and thymus) using MTT assay in culture. The methanolic extracts of six salt marsh plants ( Rosa rugosa, Ixeris tamagawaensis, Artemisia capillaris, Tetragonia tetragonoides, Erigeron annus, and Glehnia littoralis) showed very powerful suppressive effects of mouse immune cell death and significant activities of cell proliferation in vitro. Especially, the methanolic extract of Rosa rugosa was found to have fifteen times compared to the control treatment, demonstrating that Rosa rugosa may have a potent stimulation effect on immune cell proliferation. These results suggest that several salt marsh plants including Rosa rugosa could be useful for further study as an immunomodulating agent.

Seo, Youngwan; Lee, Hee-Jung; Kim, You Ah; Youn, Hyun Joo; Lee, Burm-Jong

2005-12-01

141

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, Sandra; Boix, Dani; López-Flores, Rocío; Badosa, Anna; Quintana, Xavier D.

2006-04-01

142

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

2006-05-30

143

Long-term salt marsh vertical accretion in a tidal bay with reduced sediment supply  

NASA Astrophysics Data System (ADS)

Because of damming and intensive human activities, the sediment supply to many estuaries and deltas is dramatically decreasing. In the Oosterschelde (southwest Netherlands), a storm surge barrier (SSB) and two compartmentalization dams were built in the 1980s to protect the densely inhabited inland against flooding. After these constructions, the tidal range and mean high water level in the Oosterschelde decreased by about 12% and suspended sediment concentrations in the channels dropped by 52-70% compared to the pre-barrier conditions. The vertical accretion rates of the three largest salt marshes (Rattekaai, Sint Annaland and Slaak) in the Oosterschelde in response to this decreased sediment supply were investigated. There was a general accreting trend over the entire post-barrier period (1988-2011) in all three marshes. The predicted slowdown in accretion rates by De Jong et al. (1994) did not persist, although accretion rates were lower than in the pre-barrier period. More than 20 year observations from kaoline markers showed variation of accretion rates within and among marshes. Year-to-year variation in accretion rates was large, but only weakly (not significantly) related to the duration and frequency of marsh overflow and over-marsh extreme flooding events. However, storm events are hypothesized to be responsible for the observed trends, but our observations lack the temporal resolution to identify specific storm events. Salt marshes in the Oosterschelde are expected to survive under the present sea level rise rate and subsidence rate scenarios.

Ma, Zhigang; Ysebaert, Tom; van der Wal, Daphne; de Jong, Dick J.; Li, Xiuzhen; Herman, Peter M. J.

2014-06-01

144

Remote Estimation of Salt Marsh Biophysical Parameters in the Georgia Coast: Model Cal/Val using NASA Sensors to Improve Monitoring and Restoration Efforts by the Georgia Department of Natural Resources  

NASA Astrophysics Data System (ADS)

Salt marshes are highly productive ecosystems that provide habitat and nutrition to wildlife, offer protection from flooding and storm surges, and help filter polluted run-off from upland areas. This study demonstrates the ability to identify ';hotspots' of early stages of marsh degradation which can only be delineated by evaluating marsh biophysical characteristics including distribution of chlorophyll content (Chl), leaf area index (LAI) (a ratio of green foliage area vs. ground area), and green vegetation fraction (VF) (percent green canopy cover). These biophysical characteristics are primary indicators of photosynthetic capacity, nitrogen content, and physiological status of vegetation. Through use of NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, we retrieve the above described biophysical characteristics in Georgia salt marshes. This work is significant because it allows for the first time the use of NASA satellite data to study the biophysical characteristics of salt marshes along Georgia's coast. Our results show an efficient and non-destructive biophysical mapping protocol for emergent wetlands to be used in restoration decision-making by the Georgia Department of Natural Resources. Our primary objectives are (1) to calibrate and validate a range of MODIS-based vegetation indices (VIs) and develop prototype weekly and monthly composites of the salt marsh biophysical characteristics for the coast of Georgia from 2000 through 2013, for the growing season (March-November) and (2) to perform a time-series analysis, with map products developed from MODIS imagery, to study the overall trend of salt marsh productivity during the last decade. These VIs (NDVI, WDRVI, EVI2, SAVI, and VARI) have been widely used and tested for monitoring terrestrial vegetation, but not for salt marsh ecosystems.

White, J. A.; Padgett-Vasquez, S.; Ghosh, S.; Baruch, A.; Chen, N.; Mote, J.; Mishra, D. R.

2013-12-01

145

A geohydrologic continuum theory for the spatial and temporal evolution of marsh-estuarine ecosystems  

NASA Astrophysics Data System (ADS)

Using ecosystem development theory and the River Continuum Concept as starting points, we present a new holistic theory to explain the spatial and temporal behaviour of marsh-estuarine ecosystems Along the marine-estuarine-freshwater gradient in response to sea-level rise. In this theory, a geohydrologic continuum represented by tidal channel provides a predictable physical model of how the marsh-estuarine ecosystem adapts until there is a change of state. North Inlet, South Carolina is used as an example of this marsh-estuarine continuum. Mature creeks are at the ocean-estuary interface and are strongly influenced by marine factors. Further into the estuary, less and less mature creeks are encountered which are dominated by smaller scale spatial and temporal controls such as oyster reefs. Immature or ephemeral creeks import both particulate and dissolved materials, while mature creeks export both forms of nutrients. Mid-aged creeks appear to take up particulate materials and release dissolved constituents. Ultimately, the continuum reaches the fresh-saltwater interface where a very young estuarine ecosystem invades a more mature type, under the influence of disturbance. Our new explanation satisfies most criteria for a good theory by being internally consistent to the location specified, generating testable hypothesis, not blindly adapting existing theories, agreeing with known properties of the ecosystem described and by generating new invigorating discussion within the scientific community.

Dame, R.; Childers, D.; Koepfler, E.

146

History of Delaware and New Jersey salt marsh restoration sites  

Microsoft Academic Search

Humans have modified the tidal marsh sites of the Public Service Enterprise Group Estuary Enhancement Program over the past 400 years as well as by natural processes such as sea level change and storms. We used the data reported here – photographs and maps that showed the range of changes and the time frame in which these changes occurred –

Kurt R. Philipp

2005-01-01

147

The runnelling method of habitat modification: an environment-focused tool for salt marsh mosquito management.  

PubMed

Traditional methods of managing salt marsh mosquitoes focus primarily on maximizing the reduction of mosquito populations, with minimizing environmental impact as a secondary consideration. An environment-oriented approach to salt marsh management for mosquito control, runnelling, is described and compared with other forms of habitat modification such as ditching and Open Marsh Water Management (OMWM). Runnelling alters the salt marsh as little as possible while causing significant reductions in mosquito numbers. The effect of runnelling on the environment was monitored via the following variables: water table level, substrate characteristics (moisture, salinity and pH), vegetation (height and density of each Sporobolus virginicus) and the numbers of mosquito larvae. Runnelling had a statistically significant effect on only two of the seven variables. These were the height of Sporobolus, which increased near runnels, and the number of mosquito larvae, which decreased. The main difference between ditching, OMWM and runnelling lies in the magnitude of the habitat modification. Ditching involves the greatest alteration to the marsh, and runnelling the least. Consequently, runnelling has a smaller effect on the estuarine environment as a whole than does either ditching or OMWM. PMID:2568396

Hulsman, K; Dale, P E; Kay, B H

1989-06-01

148

Fish-Nursery Use in Georgia Salt-Marsh Estuaries: The Influence of Springtime Freshwater Conditions  

Microsoft Academic Search

The fish assemblage using shallow nursery habitats in the Ogeechee River-Ossabaw Sound salt-marsh estuary, Georgia, was investigated during the winter and spring of two successive years. High river discharges during these periods produced fully freshwater conditions (all tidal stages and amplitudes) in the upper portion of the study area for up to 4 months. Abundances of Atlantic croaker Micropogonias undulatus,

S. Gordon Rogers; Timothy E. Targett; Scott B. Van Sant

1984-01-01

149

Quantification of Macrobenthic Effects on Diagenesis Using a Multicomponent Inverse Model in Salt Marsh Sediments.  

National Technical Information Service (NTIS)

Using a multicomponent inverse model, we quantified the rates of organic matter (OM) remineralization and the relative importance of major terminal electron acceptors Fe(III)-(oxy)hydroxides and SO 2/4 in salt marsh sediments with varying degrees of biotu...

Y. Furukawa A. C. Smith J. E. Kostka J. Watkins C. R. Alexander

2004-01-01

150

Using Nitrogen Stable Isotope Tracers to Track Climate Change Impacts on Coastal Salt Marshes  

EPA Science Inventory

Climate change impacts on coastal salt marshes are predicted to be complex and multi-faceted. In addition to rising sea level and warmer water temperatures, regional precipitation patterns are also expected to change. At least in the Northeast and Mid-Atlantic U.S., more severe s...

151

RIBBED MUSSELS AND SPARTINA ALTERNIFLORA PRODUCTION IN A NEW ENGLAND SALT MARSH  

Microsoft Academic Search

The ribbed mussel, Geukensia demissa, is commonly found associated with the salt marsh cordgrass, Spartina alterniflora. Mussels attach to the basal portion of S. alterniflora stems with strong proteinaceous byssal threads and deposit fecal material on the surrounding sediment as a byproduct of their filter-feeding activity. Here I demonstrate by manipulating mussel densities in the field that the presence of

MARK D. BERTNESS

1984-01-01

152

Aquatic Insects of the West River and Salt Marshes of Connecticut  

Microsoft Academic Search

The insect survey of West River Memorial Park in New Haven, Connecticut shows that freshwater aquatic communities are currently restricted to portions of the river above Chapel Street. The extensive shoreline insect communities were documented to provide a baseline for determining future changes caused by a salt marsh restoration. No endangered species were found in the park. Collections from nearby

Raymond J. Pupedis

153

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

154

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

155

Impact of Fertilization on a Salt Marsh Food Web in Georgia  

Microsoft Academic Search

We examined the response of a salt marsh food web to increases in nutrients at 19 coastal sites in Georgia. Fertilization\\u000a increased the nitrogen content of the two dominant plants, Spartina alterniflora and Juncus roemerianus, indicating that added nutrients were available to and taken up by both species. Fertilization increased Spartina cover, height, and biomass and Juncus height, but led

Caroline R. McFarlin; J. Stephen Brewer; Tracy L. Buck; Steven C. Pennings

2008-01-01

156

34S/ 32S Evidence of biogenic sulfur oxides in a salt marsh atmosphere  

NASA Astrophysics Data System (ADS)

The use of 34S/ 32S measurements to identify the source of atmospheric sulfur oxides was evaluated in a study conducted at a rural salt marsh. ? 34S values of SO 2 and non sea salt SO 2-4 collected on one side of a large salt marsh were compared with one another and with that of non sea salt SO 2-4 collected 4 km away on the opposite side of the marsh. Associations between these values indicated that the measurements were extremely precise and accurate, and that the ground level sulfur cycle was dominated by H 2S produced by bacterial sulfate reducers in anoxic marsh sediments. There was no isotopic evidence of the presence of transported pollutant SO 2-4 at this location, although the sampled air masses had passed over very large sources of anthropogenic S and high Particulate V and Pb concentrations confirmed that these air masses were contaminated with pollutant effluents. Biogenic SO 2-4 and SO 2 concentrations ranged up to 24.6 and 26?gm -3, respectively, and were highest in modified marine-tropical air masses. Associations between concentrations of V and SO 2-4 and between Pb and SO 2 suggested the participation of these trace metals (or constituents for which they function as tracers) in the atmospheric oxidation reactions of the sulfides.

Hitchcock, D. R.; Black, M. S.

157

Differential Effects of Four Abiotic Factors on the Germination of Salt Marsh Annuals  

Microsoft Academic Search

Interspecific differences in responsiveness to temperature, photoperiod, soil salinity, and soil moisture confirm the hypothesis that abiotic factors differentially affect the germination of salt marsh plants. In growth chamber experiments, four of eight annual species responded to small differences in temperature or photoperiod. Increasing soil salinity decreased the final proportion of seeds germinating and slowed germination for each of the

Gregory B. Noe; Joy B. Zedler

2000-01-01

158

Habitat structure and vegetation relationships in central Argentina salt marsh landscapes  

Microsoft Academic Search

Relationships between habitat structure and spatial variations in vegetation composition were determined in catenas of central Argentina salt marsh landscapes. Vegetation was classified following a multi-technique strategy. An analysis of species distributions along an environmental gradient was made and a redundancy analysis was used to relate the environmental variables to vegetation data. The spatial covariation was evaluated through fractal analysis.

Juan José Cantero; Rolando Leon; José Manuel Cisneros; Alberto Cantero

1998-01-01

159

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

160

Wind-Driven Sea-Level Variation Influences Dynamics of Salt Marsh Vegetation  

Microsoft Academic Search

Long-term variation of mean sea level has been considered the primary exogenous factor of vegetation dynamics in salt marshes. In this study, we address the importance of short-term, wind-induced rise of the sea surface in such biogeographic changes. There was an unusual opportunity for examining field data on plant species frequency, sea-level variation, and sedimentation acquired from the Skallingen salt

Daehyun Kim; David M. Cairns; Jesper Bartholdy

2011-01-01

161

Impacts of salt marsh plants on tidal channel initiation and inheritance  

NASA Astrophysics Data System (ADS)

Tidal channel networks are the most prominent and striking features visible in tidal wetlands. They serve as major pathways for the exchange of water, sediments, nutrients and contaminants between the wetland and the adjacent open water body. Previous studies identified topography guided sheet flows, as the predominate process for tidal channel initiation. Guided through differences in local topography, sheet flows are able to locally exceed bottom shear stress thresholds, initiating scouring and incision of tidal channels, which then further grow through head ward erosion. The fate of these channels after plant colonization is described in literature as being inherited into the salt marsh through vegetation induced bank stabilization (further referred to as vegetation stabilized channel inheritance). In this study we present a combination of flume experiments and modelling simulations elucidating the impact of vegetation on tidal channel initiation. We first studied the impact of plant properties (stiff: Spartina alterniflora versus flexible: Scirpus mariqueter) on local sediment transport utilizing a flume experiment. Then a coupled hydrodynamic morphodynamic plant growth model was set up to simulate plant colonization by these two different species in the pioneer zone at the mudflat - salt marsh transition. Based on the model we investigated the ramifications of interactions between vegetation, sediment and flow on tidal channel initiation. We specifically compared the effect of vegetation properties (such as stiffness, growth velocity and stress tolerance) on emerging channel patterns, hypothesizing that vegetation mediated channel incision (vegetation induced flow routing and differential sedimentation/erosion patterns leading to tidal channel incision) plays an active role in intertidal landscape evolution. We finally extended our model simulation by imposing pre-existing mudflat channels with different maximum depths, to investigate the impact of existing channels on vegetation mediated channel incision. This simulated landscape development was then compared to aerial photographs from the Scheldt estuary (the Netherlands) and the Yangtze estuary (China). Our results suggest a significant impact of plant properties on tidal channel network emergence, specifically in respect to network drainage density and channel width. This emphasizes the repercussions of vegetation mediated channel incision on estuarine landscape development. Further do our results point to the existence of a threshold in pre-existing mudflat channel depth favoring either vegetation stabilized channel inheritance or vegetation mediated channel incision processes. Increasing depth in mudflat channels favors flow routing via these channels, leaving less flow and momentum remaining for the interaction between vegetation, sediment and flow and therefore vegetation mediated channel incision. This threshold will be influenced by field specific parameters such as hydrodynamics (tidal range, waves, and flow), sediments and predominant plant species. Hence our study not only demonstrates to importance of plant properties on landscape development it also shows that vegetation stabilized channel inheritance or vegetation mediated channel incision are two occurring mechanisms depending on ecosystem properties, adding important information for salt marsh management and conservation.

Schwarz, Christian; Ye, Qinghua; van der Wal, Daphne; Zhang, Liquan; Ysebaert, Tom; Herman, Peter MJ

2013-04-01

162

Seasonal and topographic variations in porewaters of a southeastern USA salt marsh as revealed by voltammetric profiling+  

PubMed Central

We report electrochemical profiles from unvegetated surficial sediments of a Georgia salt marsh. In creek bank sediments, the absence of ?H2S or FeSaq and the presence of Fe(III)–organic complexes suggest that Mn and Fe reduction dominates over at least the top ca. 5 cm of the sediment column, consistent with other recent results. In unvegetated flats, accumulation of ?H2S indicates that SO42- reduction dominates over the same depth. A summer release of dissolved organic species from the dominant tall form Spartina alterniflora, together with elevated temperatures, appears to result in increased SO42- reduction intensity and hence high summer concentrations of ?H2S in flat sediments. However, increased bioturbation and/or bioirrigation seem to prevent this from happening in bank sediments. Studies of biogeochemical processes in salt marshes need to take such spatial and temporal variations into account if we are to develop a good understanding of these highly productive ecosystems. Furthermore, multidimensional analyses are necessary to obtain adequate quantitative pictures of such heterogeneous sediments.

Bull, David C; Taillefert, Martial

2001-01-01

163

Long-term changes and historical uses of one of the largest French salt-marshes since 1705  

NASA Astrophysics Data System (ADS)

The salt-marshes of the Baie de l'Aiguillon (Western France) are among the largest of Western Europe. Thanks to exceptional historical data, including old maps, manuscripts and aerial photographs, we propose one of the first long-term accurate cartographies of such a large salt-marsh, dating back to the beginning of the 18th century. Like other salt-marshes in Western Europe, including those of the Mont Saint-Michel Bay (France), we found that they are expanding for the three last decades. However, our historical analysis also reveals that the area of these salt-marshes shrinked by two thirds over the last three centuries, due to massive land-reclamations starting from the mid-17th century. As revealed by historical testimonies and archeological remains, we also demonstrated that these salt-marshes were actively mowed as soon as the 1700s. In consequence, the oldest and the non-used parts of such salt-marshes correspond to very restricted patches that may present a high conservation stake. In the context of massive land-use and land-cover changes along the European coastal zones, historical analyses exploring long-term changes and historical uses of coastal habitats may help to identify old and natural patches of coastal habitats. Salt-marshes, that are easy to map and monitor, are good candidates for such investigations.

Godet, Laurent; Pourinet, Laurent; Decaulne, Armelle

2014-05-01

164

MARSH 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...

165

Salt marsh equilibrium states and transient dynamics in response to changing rates of sea level rise and sediment supply  

NASA Astrophysics Data System (ADS)

Understanding and predicting the response of salt-marsh bio-geomorphic systems to changes in the rate of sea level rise and sediment supply is an issue of paramount importance due to the crucial role exerted by salt marshes within the tidal landscape. Salt-marsh platforms, in fact, buffer coastlines against storms, filter nutrients and pollutants from tidal waters, provide nursery areas for coastal biota, and serve as a sink for organic carbon. 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 which control salt-marsh response to current natural climate changes and to the effects of variations in sediment supply. The results of our analytical model of salt-marsh bio-morphodynamic evolution in the vertical plane, accounting for two-way interactions between ecological and geomorphological processes, show that marshes are more resilient to a step decrease in the rate of relative sea level rise rather than to a step increase of the same magnitude. Interestingly, marshes respond more rapidly to an increase in sediment load or vegetation productivity, rather than to a decrease (of the same amount) in sediment load or vegetation productivity. Model results also suggest that marsh stability is positively correlated with tidal range: marshes with high tidal ranges respond more slowly to changes in the environmental forcings and therefore are less likely to be affected by perturbations than their counterparts in low tidal ranges. Finally, the model suggests that, in the case of a oscillating rate of sea level rise, marsh stratigraphy will be unable to fully record short term fluctuations in relative mean sea level, whereas it will be able to capture long term fluctuations particularly in sediment rich, microtidal settings.

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

2012-12-01

166

The effect of a seasonal change in canopy structure on the photosynthetic efficiency of a salt marsh  

Microsoft Academic Search

A seasonal decline in the photosynthetic efficiency of a Chesapeake Bay salt marsh occurs concurrently with a seasonal shift in foliage canopy structure from erect- to horizontal-leaved. Infrared gas analysis was used to measure net photosynthesis by isolated sections of marsh before and after the canopy was subjected to experimental manipulations designed to mimiic the natural canopy change. During June

S. N. Turitzin; B. G. Drake

1981-01-01

167

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

168

Influence of flooding and vegetation on carbon, nitrogen, and phosphorus dynamics in the pore water of a Spartina alterniflora salt marsh  

Microsoft Academic Search

Four sites were selected in a salt marsh in the Bahía Blanca Estuary (Argentina): (1) low marsh (flooded by the tide twice daily) vegetated by S. alterniflora; (2) non-vegetated low marsh; (3) high marsh (flooded only in spring tides) vegetated by S. alterniflora; (4) non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients (ammonium, nitrate,

Vanesa L. Negrin; Carla V. Spetter; Raúl O. Asteasuain; Gerardo M. E. Perillo; Jorge E. Marcovecchio

2011-01-01

169

Zonation of spiders (Araneae) and carabid beetles (Coleoptera: Carabidae) in island salt marshes at the North Sea coast  

Microsoft Academic Search

The specific communities of spiders and carabid beetles of island salt marsh habitats of the East Frisian Island chain at\\u000a the German North Sea coast were investigated. During the vegetation periods of 1997 and 1998 three pitfall trapping transects\\u000a were installed on the islands of Borkum and Wangerooge. Within the salt marshes, transects extended from 0 m to 175 m. Elevation\\u000a gradients

Oliver-D. Finch; Heinrich Krummen; Friedhelm Plaisier; Walter Schultz

2007-01-01

170

Sulfide variation in the pore and surface waters of artificial salt-marsh ditches and a natural tidal creek  

Microsoft Academic Search

Pore and surface water sulfide variation near artificial ditches and a natural creek are examined in salt marshes bordering\\u000a the Indian River Lagoon in east-central Florida. Pore water sulfide concentrations ranged from 0 ?g-at I?1 to 1,640 ?g-at I?1. On average, the natural creek had the lowest sulfide concentrations (mean ?1) and the perimeter ditch of a managed salt marsh

Jorge R. Rey; John Shaffer; Tim Kain; Robert Stahl; Roy Crossman

1992-01-01

171

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

172

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

173

Impact of exposure of crude oil and dispersant (COREXIT® EC 9500A) on denitrification and organic matter mineralization in a Louisiana salt marsh sediment.  

PubMed

In response to the 2010 oil spill from the explosion of the Deepwater Horizon oil rig in the Gulf of Mexico, this experiment aims to study the ecological impact of the crude oil and dispersant (COREXIT® EC 9500A) in a coastal salt marsh ecosystem. The marsh sediment was incubated under an anaerobic condition with exposure to the crude oil or/and dispersant. The experiments were conducted in two continuous phases of nitrate addition to study denitrification potential using acetylene blockage technique and organic matter mineralization potential indicated by CO2 production in the sediment. Results show that the oil slightly (with no statistical significance p>0.05) increased both the denitrification and organic matter mineralization activities, likely due to oil components serving as additional organic matter. In contrast, the dispersant significantly (p<0.05) inhibited denitrification, but stimulated organic matter mineralization activities in the sediment due to unknown mechanisms. As a consequence, redox potentials (Eh) were much lower in the dispersant treated systems. The ecological impacts from the dispersant exposure may come from two fronts. First, loss of organic matter from the coastal marsh will threaten the long-term stability of the ecosystem, and the decrease in denitrification activity will weaken the N removal efficiency. Secondly, more reducing conditions developed by the dispersant exposure will likely preserve the oil in the ecosystem for an extended period of time due to weaker oil biodegradation under anaerobic conditions. PMID:24582034

Shi, Rujie; Yu, Kewei

2014-08-01

174

Polychlorinated biphenyls in two salt marsh sediments of the Venice Lagoon  

Microsoft Academic Search

Polychlorinated biphenyls (PCBs) were measured in two dated salt marsh cores of the Venice Lagoon to assess their input chronology\\u000a and to evaluate the importance of atmospheric deposition as a source. Sampling sites were chosen in order to evidence the\\u000a differences between areas located leeward and windward with respect to inputs originating in both the city of Venice and the

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

175

The role of lesser snow geese as nitrogen processors in a sub-arctic salt marsh  

Microsoft Academic Search

Ammonia volatilization losses from faeces of Lesser Snow Geese were measured during the summer of 1987 on the salt-marsh flats at La Pérouse Bay. Amounts of ammonia volatilized increased with increasing ambient temperature, and ranged from 1.0 to 15.1 mg N per 100 mg of nitrogen present as soluble ammonium ions at the start of the 8-h experiment. Using estimates

R. W. Ruess; D. S. Hik; R. L. Jefferies

1989-01-01

176

Soil salinity and moisture gradients and plant zonation in Mediterranean salt marshes of Southeast Spain  

Microsoft Academic Search

For two years, we measured soil moisture, pH, salinity, and ion concentrations bimonthly from 55 vegetation plots in six Mediterranean\\u000a salt marshes of SE Spain. Edaphic characteristics during dry and wet seasons were compared within six selected plant communities.\\u000a The dominant species in each of these communities were Suaeda vera, Lygeum spartum, Limonium sp, Sarcocornia fruticosa, Halocnemum strobilaceum, and Arthrocnemum

José Alvarez Rogel; Francisco Alcaraz Ariza; Roque Ortiz Silla

2000-01-01

177

Notes: Gross Conversion Efficiencies of Mummichog and Spotfin Killifish Larvae from a Georgia Salt Marsh  

Microsoft Academic Search

We conducted two experiments to determine gross food conversion efficiencies (K 1) for larvae of two common salt-marsh fundulids, mummichogs Fundulus heteroclitus and spotfin killifish Fundulus luciae. Larvae were fed a known number of brine shrimp nauplii (Artemia sp.) daily in both experiments. In experiment 1, conducted at 27°C and with a 14-h light (L): 10-h dark (D) photoperiod, mummichog

R. T. Kneib; J. H. Parker

1991-01-01

178

Fate of plant detritus in a European salt marsh dominated by Atriplex portulacoides (L.) Aellen  

Microsoft Academic Search

This paper deals with the organic matter dynamics of a dwarf shrub species, Atriplex portulacoides, which characterizes the majority of ungrazed European salt marshes. These dynamics were investigated by the simultaneous\\u000a estimation of primary production, litter production, decomposition processes and accumulation of organic matter in sediment.\\u000a We used harvested biomass techniques and the litter-bag method, as well as more recent

V. Bouchard; V. Creach; J. C. Lefeuvre; G. Bertru; A. Mariotti

1998-01-01

179

Radium isotopes in salt marsh and estuarine environments  

Microsoft Academic Search

Dissolved ²²⁶Ra, ²²⁸Ra, and ²²⁴Ra data from the tidal creeks and interstitial water and radium and thorium data from the sediments of salt marches in South Carolina, Delaware, and Massachusetts are presented. Dissolved radium activities in the tidal creeks were 2-3 times higher in the summer than at any other time because of increased bioturbation rates during the warm months.

1986-01-01

180

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

NASA Astrophysics Data System (ADS)

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 Island, Georgia, salt marsh. Based on results from lignin oxidation product (LOP) analysis of leaves, lignin in the S. alterniflora was shown to be significantly degraded in both studies, with 13 ± 2% and 25 ± 12% of the total lignin mass loss occurring over the 496-day litterbag and 146-day tagged studies, respectively. A comparison of the results from both studies suggests that most of the calculated lignin loss (> 90%) occurs early in the degradation history of the plant, with a significant portion occurring while the plant is still standing in the salt marsh. Further detailed evaluation of this loss demonstrates that selective lignin degradation occurs in S. alterniflora, deriving from the preferential loss of labile lignin moieties. The most labile component, trans-ferulic acid, accounted for 57% and 82% of the total lignin loss in the litterbag and tagged studies, respectively, based on normalization to syringyl-phenol concentrations. Comparison of these two data sets supports the following approximate lignin stability sequence for S. alterniflora:S ? Ca ? V > P > Fa. Based on measured changes in both the lignin mass loss and the LOP acid/aldehyde ratio, as well as evidence suggesting that degradation occurred under oxic conditions, it is proposed that aromatic ring cleavage was the predominant mechanism of lignin degradation in both studies. In light of these results and those from other recent lignin degradation studies, we discuss the geochemical consequences regarding the usefulness of lignin oxidation products as quantitative tracers of vascular plant-derived organic matter being transported, deposited, and buried in aquatic environments.

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

1992-10-01

181

C3\\/C4 variations in salt-marsh sediments: An application of compound specific isotopic analysis of lipid biomarkers to late Holocene paleoenvironmental research  

Microsoft Academic Search

In salt-marshes, bulk carbon isotope values reflect organic matter contributions not only from salt-marsh plants, but also from algal and bacterial inputs, as well as allochthonous terrestrial organic matter. In the present study, compound specific isotope analysis was applied to a core and modern plant samples collected from a Machiasport, Maine salt-marsh. We sampled 10 plant species common to the

Benjamin R. Tanner; Maria E. Uhle; Joseph T. Kelley; Claudia I. Mora

2007-01-01

182

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

183

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

2007-07-15

184

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

185

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

186

Magnitudes and spatial and temporal patterns of self-organized processes between geomorphology and biota that drive salt marsh evolution  

NASA Astrophysics Data System (ADS)

Many complex systems show non-equilibrium fluctuations, often determining the spontaneous evolution towards a critical state. In this context salt marshes are known to be characterized by complex patterns in both geomorphological and ecological features, which often appear to be strongly correlated. One of the main drivers on low-order channel network geometry is the hydrodynamic forcing entering the system in the form of an intermittent stress: the occurrence of infrequent rainfall events determines saturation-excess overland flow, which results in higher stream energy to be dissipated through an increase in cross section and meandering of the tidal channels in the marsh. This external driver determines a second, important effect on the intertidal zone: together with the emergence of a higher number of minor draining channels, salt marshes are provided with pulses of sediment input, causing a vertical build-up that allows pioneer species to colonize new areas of mudflat and channels. This eventually leads to salt marsh development through the higher frequency of occurrence and horizontal spread of marsh pioneer patterns, coupled with the displacement of the limit between the salt marsh and mudflat. As opposed to infrequent events, a much more frequent source of variation and uncertainty affecting the system is the difference between the observed and astronomical tide, which is referred to as surge. Since it would be difficult to simultaneously monitor these parameters through field surveys, and even harder to analyze them over medium to large time scales, we propose a remote sensing approach to monitor the temporal dynamics of both biotic and abiotic factors in salt marshes. We characterized the complex interactions between morphology and biota in two salt marshes in the densely populated Scheldt estuary through the implementation of different algorithms on multispectral endmember fraction maps from optical space-borne remote sensing. Multitemporal fractional abundance maps spanning from 1986 to 2011 were used to identify the interaction between vegetation pattern dynamics and channel drainage density, and integrated with field sampling and in situ spectroradiometry. The objectives were to: a) analyze and validate the processing procedure used to define the patterns of macrophyte vegetation cover; b) obtain field data on microphytobenthos biomass in two intertidal mudflat areas differing in the degree of sediment cohesiveness; c) integrate spectroradiometric measurements with simultaneous sampling; d) build a spectral library of salt marsh vegetation composition and zonation of Northern Europe estuarine areas. The latter can then be compared with vegetation field sampling data already available on the Plymouth estuary, Po Delta and Venice lagoon, in order to support the classification of the different surface cover types for the development of new methods of monitoring salt marsh-mudflat systems.

Cornacchia, L.; Taramelli, A.; Valentini, E.; Monbaliu, J. A.; Sabbe, K.

2012-12-01

187

Accumulation of COGEMA-La Hague-derived reprocessing wastes in French salt marsh sediments.  

PubMed

Over the past five decades, authorized low-level discharges from coastal nuclear facilities have released significant quantities of artificial radionuclides into the marine environment. In northwest Europe, the majority of the total discharge has derived from nuclear reprocessing activities at Sellafield in the United Kingdom and COGEMA-La Hague in France. At the Sellafield site, a significant amount of the discharges has been trapped in offshore fine sediment deposits, and notably in local coastal and estuarine sediments, and much research has been focused on understanding the distribution, accumulation, and reworking of long-lived radionuclides in these deposits. In contrast, there are few high-resolution published data on the vertical distribution of radionuclides in fine-grained estuarine sediments near, and downstream of, COGEMA-La Hague. This paper therefore examines the vertical distribution of a range of anthropogenic radionuclides in dated salt marsh cores from two estuaries, one adjacent to, and the other downstream of, the COGEMA-La Hague discharge point (the Havre de Carteret at Barneville-Carteret and the Baie de Somme, respectively). The radionuclides examined show a vertical distribution which predominantly reflects variations in input from COGEMA-La Hague (albeit much more clearly at Barneville-Carteret than at the Baie de Somme site), and Pu isotopic ratios are consistent with a La Hague, rather than weapons' fallout, source. Because of sediment mixing, the marshes apparently retain an integrated record of the La Hague discharges, rather than an exact reproduction of the discharge history. Sorption of radionuclides increases in the order 90Sr < 137Cs < 60Co < 239,240Pu, which is consistent with Kd values reported in the literature. In general, the radionuclide activities observed at the sites studied are low (particularly in comparison with salt marsh sediments near the Sellafield facility), but are similar to those found in areas of fine sedimentation in the central Channel. These marshes are not major sinks for discharged reprocessing wastes. PMID:12523411

Cundy, Andrew B; Croudace, Ian W; Warwick, Phillip E; Oh, Jung-Suk; Haslett, Simon K

2002-12-01

188

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

189

The flux of chloroform and tetrachloromethane along an elevational gradient of a coastal salt marsh, East China.  

PubMed

The fluxes of trichloromethane (CHCl(3), CM) and tetrachloromethane (CCl(4), TCM) were seasonally measured using static flux chambers over an annual cycle in a coastal salt marsh, East China. The salt marsh presented as a large sink for both the compounds in the growing season (from April to October), but it was a minor source for the gas species in the non-growing season. Generally, the cordgrass marsh acted as a sink of CM and TCM. The net consumption of CM and TCM observed in the study marsh may result from the high ambient atmospheric concentrations and enriched soil organic matter that result in anoxic sediments. Higher plants were suggested to be an important sink for CM and TCM in the growing season, but a net source in the non-growing season. However, the mechanism responsible for the plant removal process is not clear. PMID:17234312

Wang, Jinxin; Qin, Pei; Sun, Shucun

2007-07-01

190

Diet Composition of Mummichogs, Fundulus heteroclitus, from Restoring and Unrestricted Regions of a New England (U.S.A.) Salt Marsh  

NASA Astrophysics Data System (ADS)

Diet composition of mummichogs, Fundulus heteroclitus, from three marsh habitats (creeks, pools, and marsh surface) within tidally restored and an adjacent unrestricted (reference) region of Sachuest Point salt marsh (Middletown, RI, U.S.A.) was examined. Major diet components were detritus, copepods, diatoms, insects (larvae and adults), ostracods, and chironomids. Total length, wet weight, and gut fullness of mummichogs were equivalent within habitats between the restoring and unrestricted marshes. Diet composition and percent abundance of diet items were also similar within habitats between the unrestricted and restoring marshes. However, differences in diet patterns were observed among habitats (creeks, pools, and marsh surface) within each marsh. Fish collected from creeks had fuller guts than those sampled from the marsh surface for both the restoring and unrestricted marsh. Diet composition also differed among marsh habitats, but only within the restoring marsh. In the restoring marsh, fish sampled from the creeks consumed primarily detritus, diatoms, and ostracods, whereas fish from the pools consumed mainly detritus, copepods, chironomids, and insects. Differences in diet composition among habitats were most likely a reflection of prey availability. This study provides evidence that tidally restored marshes can provide similar food resources as unrestricted marshes, in terms of consumption patterns of dominant marsh consumers, within the first year after restoration, before major shifts in dominant vegetation (i.e. from Phragmites australis to Spartina spp.) occur.

James-Pirri, M. J.; Raposa, K. B.; Catena, J. G.

2001-08-01

191

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

192

The ecology of temperate salt-marsh fucoids. II. In situ growth of transplanted Ascophyllum nodosum ecads  

Microsoft Academic Search

Growth, in terms of length, weight, and number of branches and\\/or dichotomies, in transplanted specimens of Ascophyllum nodosum ecad scorpioides in a temperate salt marsh is described. The ecad scorpioides, when transplanted from its characteristic habitat on the mid-intertidal, Spartina alterniflora-dominated, marsh flats to a location near mean low-water developed characteristics normally associated with A. nodosum ecad mackaii. The growth

B. H. Brinkhuis; R. F. Jones

1976-01-01

193

Assessment of Hydraulic Restoration of San Pablo Marsh, California  

Microsoft Academic Search

Inter-tidal marshes are dynamic diverse ecosystems at the transition zone between terrestrial and ocean environments. Geomorphologically, inter-tidal salt marshes are vegetated landforms at elevations slightly greater than mean tidal levels that have distributed channels formed under ebb (drainage) tidal flows that widen and deepen in the seaward direction. The drainage channels enable tidal flows to circulate sediments and nutrients through

Mark E. Grismer; J. Kollar; J. Syder

2004-01-01

194

The Hydrologic Structure and Function of the West River Marsh  

Microsoft Academic Search

This paper updates earlier hydrologic studies of the marsh in West River Memorial Park, New Haven, Connecticut. Throughout the 1800s and 1900s, drainage, filling, and the installation of 12 tide gates (in 1919) progressively trans- formed the park's original salt marsh ecosystem into a system dominated by common reed (Phragmites australis). In 1992, we conducted a hydrologic study to assess

Paul K. Barten; William L. Kenny

195

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

196

The salt marsh vegetation spread dynamics simulation and prediction based on conditions optimized CA  

NASA Astrophysics Data System (ADS)

The biodiversity conservation and management of the salt marsh vegetation relies on processing their spatial information. Nowadays, more attentions are focused on their classification surveying and describing qualitatively dynamics based on RS images interpreted, rather than on simulating and predicting their dynamics quantitatively, which is of greater importance for managing and planning the salt marsh vegetation. In this paper, our notion is to make a dynamic model on large-scale and to provide a virtual laboratory in which researchers can run it according requirements. Firstly, the characteristic of the cellular automata was analyzed and a conclusion indicated that it was necessary for a CA model to be extended geographically under varying conditions of space-time circumstance in order to make results matched the facts accurately. Based on the conventional cellular automata model, the author introduced several new conditions to optimize it for simulating the vegetation objectively, such as elevation, growth speed, invading ability, variation and inheriting and so on. Hence the CA cells and remote sensing image pixels, cell neighbors and pixel neighbors, cell rules and nature of the plants were unified respectively. Taking JiuDuanSha as the test site, where holds mainly Phragmites australis (P.australis) community, Scirpus mariqueter (S.mariqueter) community and Spartina alterniflora (S.alterniflora) community. The paper explored the process of making simulation and predictions about these salt marsh vegetable changing with the conditions optimized CA (COCA) model, and examined the links among data, statistical models, and ecological predictions. This study exploited the potential of applying Conditioned Optimized CA model technique to solve this problem.

Guan, Yujuan; Zhang, Liquan

2006-10-01

197

Salt marsh plants ( Juncus maritimus and Scirpus maritimus) as sources of strong complexing ligands  

NASA Astrophysics Data System (ADS)

This work aimed to evaluate, in vitro, the capability of roots of salt marsh plants to release strong Cu-complexing ligands and to ascertain whether Cu contamination would stimulate ligands' exudation or not. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location and spiked with Cu 2+ in the range 0-1600 nM to obtain plant exudates. In the final solutions as well as in sediment pore water total dissolved Zn and Cu, Cu-complexing ligand concentrations and the respective conditional stability constants ( KCuL') values were determined by voltammetry. This study demonstrated that plants are able to release, in a short period of time, relatively high amounts of strong Cu-complexing ligands (56-265 nmol g root-1), which differed among plants and sampling site but were independent of the season. Cu contamination did not stimulate exudation of Cu-complexing ligands. On the other hand, in media contaminated with Cu both plants accumulated relatively high amounts (29-83%) of the initially dissolved Cu, indicating that they have alternative internal mechanisms for Cu detoxification. Cu exchange between roots and medium (either accumulation in contaminated medium or release in the absence of Cu) was more intense for S. maritimus than for J. maritimus. It was observed that exudate solutions obtained in the absence of added Cu and sediment pore water (the densities of roots observed inside the salt marsh where comparable to those used in the in vitro experiments), displayed similarities in terms of total dissolved metals, Cu-complexing ligands concentrations, values of KCuL' (12 < log KCuL' < 14), as well as patterns of variation among seasons (only observed for Zn). These results are novel and point out that salt marsh plants may be the source at least partially of the strong organic ligands found in the sediment pore water in shallow marginal areas. The capability of salt marsh plants to release strong organic ligands into the environment, conjugated with their known capacity to oxidize anaerobic sediment around roots, indicate that these plants can play a role in controlling metal speciation in the water/sediment interface.

Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

2008-03-01

198

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

199

Using the radium quartet for evaluating groundwater input and water exchange in salt marshes  

NASA Astrophysics Data System (ADS)

The fluxes of 226Ra (half-life = 1600 years) and 228Ra (half-life = 5.7 years) from the North Inlet salt marsh to the sea are much larger than can be supported by decay of their Th parents in the surface marsh sediments. These fluxes are sustained almost entirely by groundwater flow through the marsh. An average groundwater flow of approximately 10 cm 3 cm -2 day -1 is indicated if the groundwater activities we have measured are representative. The fluxes of 223Ra (half-life = 11.4 day) and 224Ra (half-life = 3.6 day) are factors of 22, and ten more than those expected from the flux of 226Ra. Groundwater also sustains most of the flux of the short-lived isotopes. The measured Ra activity ratio pattern in the marsh creeks matches the groundwater signature but is distinct from the pattern of the parent thorium isotopes in the sediment. We present a model to explain the anomalous distribution pattern of these isotopes. Despite their large throughput, the inventories of desorbable 226Ra and 228Ra in the top 15 cm sediment layer are very low. Nevertheless, the activities of 226Ra and 228Ra in the porewaters are large, indicating a low distribution coefficient (˜10) for radium and a short retention time (˜10 days) in the surface sediment layer. We surmise that groundwater flow may be a significant source of radium isotopes in the waters of shallow estuaries and coastal margins. This source must be recognized while considering mass balance of any tracer, be it radium, nutrients, other metals, or ?18O.

Rama; Moore, Willard S.

1996-12-01

200

Rhizosphere and flooding regime as key factors for the mobilisation of arsenic and potentially harmful metals in basic, mining-polluted salt marsh soils  

Microsoft Academic Search

The occurrence of mining areas in the vicinities of salt marshes may affect their ecological functions and facilitate the transfer of pollutants into the food chain. The mobilisation of metals in salt marsh soils is controlled by abiotic (pH, redox potential) and biotic (influence of rhizosphere) factors. The effect of the rhizosphere of two plant species (Sarcocornia fruticosa and Phragmites

Antonio María-Cervantes; Héctor M. Conesa; María Nazaret González-Alcaraz; José Álvarez-Rogel

2010-01-01

201

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

202

Tritium Accumulation in Salt Marsh Sediments From the Severn Estuary, UK  

NASA Astrophysics Data System (ADS)

Two shallow sediment cores (to 0.5 m) have been collected from salt marshes in the Severn estuary, UK, as part of a study of the impact of tritium (3H) discharges into the estuary. These discharges are atypical; they have routinely contained both tritiated water (HTO) and organically bound tritium (OBT) since 1982. Tritium present as HTO is usually assumed to be diluted and dispersed on release into the marine environment. However the organic component of this discharge has resulted in significant accumulation of 3H in the estuarine sediments (0.8 Bq/g fresh weight) and biota (24.8 Bq/g dry weight in flounder (McCubbin et al, 2001)). The tritium profiles from the dated salt marsh cores correlate with the decay-corrected organic 3H discharge record. This chronological record suggests that tritium has been retained over decadel timescales, with limited loss by organic matter degradation. This indicates that the tritiated organic molecules are refractory. The apparent persistence of 3H labelled sediments in the estuary has implications for the long-term impact on the environment of 3H discharges containing high proportions of OBT.

Morris, J. E.; Warwick, P. E.; Croudace, I. W.; Howard, A. G.

2004-05-01

203

Morphodynamics of Holocene salt marshes: a review sketch from the Atlantic and Southern North Sea coasts of Europe  

NASA Astrophysics Data System (ADS)

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 individual extent, to an enormous number each of an area no greater than tens to a few hundred hectares. These marshes and associated environments are under complex natural controls and experienced from the mid-Holocene onward human exploitation and, increasingly, interference. The main external controls are the sea-level, tidal and sediment-supply regimes. Intrinsic infuences are provided by the halophytic vegetation and sediment autocompaction. Upward sea-level movements and autocompaction combine to provide accomodation space within which marshes build upward. Field data and simulation modelling show that youthful mineralogenic marshes grow up rapidly and can mature within a few hundred years of inception. They consist of a vegetated platform dissected typically by extensive networks of blind-ended, branching tidal creeks and gullies. The flow-resistant surface vegetation, shaping the combined wave-tide boundary layer on the platforms, both traps and binds tidally introduced mineral sediment, but also contributes an organic component of indigenous origin to the deposit. When sea-level becomes stable or falls, however, in response to century-millennial scale fluctuations, the organic sediment component becomes dominant and mineralogenic marshes are transformed into organogenic ones. Organogenic marshes normally display a considerable range of sub-environments which create much spatial variation in the peat facies which accumulate. At an advanced stage, domed raised bogs, rising significantly above the general landscape, may appear on the marshes. Because peat is such a porous and permeable sediment, and there is little or no tidal inundation, organogenic marshes in Northwest Europe typically lack surface channels for internal drainage. The stratigraphic sequences accumulated during the Holocene beneath coastal marshes and high tidal flats typically present an alternation on a vertical scale of decimetres to metres of silts (mineralogenic marshes, high intertidal mudflats) and peats (organogenic highest intertidal-supratidal marshes). Coastal barriers and some channels are represented by local accumulations of sand and/or gravel. The silts and peats form couplets which are generally considered to be related to fluctuations of sea-level about the general upward trend. Field investigations and modelling show that, in areas where marshes are mature, the upward change from an organogenic to a sequence of mineralogenic marshes (transgressive overlaps) is accompanied by the initiation and invasive development of a branching network of tidal creeks. These decay and infill during the reversal of the environmental sequence and the approach, expressed as a series of regressive overlaps, of the next set of peat-forming conditions. The operation of the continuous, progressive, irreversible and asymptotic process of sediment autocompaction exerts a major, secondary control on depositional regimes and marsh behaviour. A variety of local responses are consequently possible in an extensive marsh, even though the marsh may be everywhere in dynamic equilibrium with environmental factors. Autocompaction also strongly shapes the character of Holocene coastal sequences as now perceived, introducing significant stratigraphic distortions and displacements which, for the time being, limit the accuracy of sea-level curves and rates of sea-level change based on dated intercalated peats. Prehistoric humans benefitted from the resources of coastal salt marshes, especially at the times when peat marshes begin to be transgressed. Peat domes not yet fully collapsed may have provided vantage points for seasonal ocupancy or even settlement from which the richer resourc

Allen, J. R. L.

2000-07-01

204

Temporal trends in microbial abundance and biodegradation in Louisiana salt marshes following the Deepwater Horizon oil spill  

NASA Astrophysics Data System (ADS)

The Deepwater Horizon oil spill that began in April 2010 released approximately 4.9 million barrels of crude oil into the Gulf of Mexico waters. Coastal salt marshes experienced moderate to heavy oiling as spilled oils washed ashore and threatened economically important habitats. In situ biodegradation of petroleum by microbes is one of the most effective methods used to remediate oil spills. However, demonstrating biodegradation can be challenging due to heterogeneous distributions of contaminants and dynamic conditions of coastal ecosystems. Salt marshes provide a unique opportunity in which variations in the natural abundance of ?13C can be used to confirm in situ biodegradation of petroleum. Marsh grasses, specifically Spartina sp., have ?13C values of -12 to -14‰ whereas the BP crude oil has a ?13C signature of -27‰. Thus, the 13C content of microbial membrane lipids (which reflects their carbon source) can be used to detect incorporation of petroleum-derived carbon. We investigated biodegradation in marsh sediments in oiled and non-oiled portions of Barataria Bay, Louisiana which experienced some of the most extensive oil contamination. Samples were collected 3, 9 and 15 months following Deepwater Horizon oil intrusion to assess biodegradation over time. Total alkane and PAH analyses confirmed that by Oct 2011 (15 months), concentrations had been significantly reduced (by up to 50,000 ug/kg at some sites). Microbial phospholipid fatty acids (PLFA) analysis revealed that cell densities decreased over the 1 year sampling period across both oil-impacted and non-impacted sites indicating that, rather than petroleum presence, seasonal variability was likely the primary control on microbial abundance. The ranges of ?13C PLFA values in oil-impacted (-26.7 to -30.5‰ ± 1.0) and non-impacted sediments (-24.5 to -33.3‰ ± 0.7) in Oct 2010 overlap, thereby reducing confidence in confirmation of biodegradation at this time point. However, in Oct 2011, PLFA from oil-impacted and non-impacted sediments were found to have a ?13C difference of 5.4‰ (oil-impacted = -31.7‰ ± 0.5, non-impacted = -26.3‰ ± 0.5) suggesting that more depleted carbon from petroleum may be cycling within the system one year later notwithstanding the fact that PAH and alkane concentrations at this time are quite low. In order to provide greater resolution and insight into biodegradation, ongoing work is applying natural abundance radiocarbon (14C) analysis of microbial PLFA, which has become a useful tool in elucidating microbial carbon sources in complex environments. Petroleum-derived carbon contains no significant 14C due to its geological age. Therefore, microbial uptake and metabolism of petroleum-derived carbon reduces the 14C content of their membrane lipids relative to the surrounding natural organic matter. Results will allow us to not only confirm biodegradation in situ, but also to assess cycling of petroleum-derived carbon. Concurrently, a survey of the microbial community across all three domains (bacteria, archaea, eukarya) is being carried out by 454 pyrosequencing to confirm the presence of oil-degraders and assess changes in microbial diversity over time. Our study is the first to apply natural abundance radiocarbon analysis to the Deepwater Horizon oil spill and will provide an in depth understanding of biodegradation over time.

Mahmoudi, N.; Fulthorpe, R. R.; Zimmerman, A. R.; Silliman, B. R.; Slater, G. F.

2012-12-01

205

Biodiversity of arbuscular mycorrhizal fungi in roots and soils of two salt marshes.  

PubMed

The occurrence of arbuscular mycorrhizal fungi (AMF) was assessed by both morphological and molecular criteria in two salt marshes: (i) a NaCl site of the island Terschelling, Atlantic Coast, the Netherlands and (ii) a K(2)CO(3) marsh at Schreyahn, Northern Germany. The overall biodiversity of AMF, based on sequence analysis, was comparably low in roots at both sites. However, the morphological spore analyses from soil samples of both sites exhibited a higher AMF biodiversity. Glomus geosporum was the only fungus of the Glomerales that was detected both as spores in soil samples and in roots of the AMF-colonized salt plants Aster tripolium and Puccinellia sp. at both saline sites and on all sampling dates (one exception). In roots, sequences of Glomus intraradices prevailed, but this fungus could not be identified unambiguously from DNA of soil spores. Likewise, Glomus sp. uncultured, only deposited as sequence in the database, was widely detected by DNA sequencing in root samples. All attempts to obtain the corresponding sequences from spores isolated from soil samples failed consistently. A small sized Archaeospora sp. was detected, either/or by morphological and molecular analyses, in roots or soil spores, in dead AMF spores or orobatid mites. The study noted inconsistencies between morphological characterization and identification by DNA sequencing of the 5.8S rDNA-ITS2 region or part of the 18S rDNA gene. The distribution of AMF unlikely followed the salt gradient at both sites, in contrast to the zone formation of plant species. Zygotes of the alga Vaucheria erythrospora (Xanthophyceae) were retrieved and should not be misidentified with AMF spores. PMID:19220401

Wilde, Petra; Manal, Astrid; Stodden, Marc; Sieverding, Ewald; Hildebrandt, Ulrich; Bothe, Hermann

2009-06-01

206

On the population biology and meiofaunal characteristics of Manayunkia aestuarina (Polychaeta: Sabellidae: Fabricinae) from a South Carolina salt marsh  

Microsoft Academic Search

The size (age) class structure of a population of Manayunkia aestuarina (Bourne) was monitored in a South Carolina salt marsh for 1 year. Reproduction in this polychaete was discontinuous; brooded embryos and juvenile recruitment were not observed in winter months (November March). The North American population of M. aestuarina displays different reproductive traits from those reported in England although population

Susan S. Bell

1982-01-01

207

EFFECTS OF SALT MARSH ALTOSID EXPOSURE ON FEMALE GROWTH & PRODUCTION IN GULF SAND FIDDLER CRAB, UCA PANACEA  

EPA Science Inventory

Effects of Salt Marsh Altosid(R) Exposure on Female Growth and Reproduction in the Gulf Sand Fiddler Crab, Uca panacea (Abstract). Presented at the 62nd Annual Meeting of the Association of Southern Biologists, 4-7 July 2001, New Orleans, LA. 1 p. Adult Uca panacea were p...

208

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

209

Copper, lead and zinc in salt marsh sediments of the Severn Estuary, UK: The potential for their early diagnetic mobility.  

PubMed

A detailed lithostratigraphic analysis already exists for salt marsh sediments of the Severn Estuary, which provides an ideal background for an investigation of phase associations of trace elements within sediment depth profiles. The first stages of a detailed investigation are reported in which phase associations of Cu, Pb and Zn are related to early diagenetic processes. PMID:24202421

Rae, J E

1989-12-01

210

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...

211

The effect of macrofauna, meiofauna and microfauna on the degradation of Spartina maritima detritus from a salt marsh area  

Microsoft Academic Search

Decomposition of salt marsh plants results from physical, chemical and biological processes including abiotic and biotic fragmentation, microbial decay and chemical transformation. According to literature data, only a few species have the ability to feed directly on living plant material, so fungi and bacteria seem to be the principal competitors for the organic substrates. Nevertheless, by consuming bacteria, protists and

Ana Isabel Lillebø; Mogens R. Flindt; Miguel Ângelo Pardal; João Carlos Marques

1999-01-01

212

Impact of Deepwater Horizon Oil Contamination on the Aqueous Geochemistry of Salt Marsh Sediment/Seawater Microcosms  

NASA Astrophysics Data System (ADS)

On April 20th, 2010, the Deepwater Horizon oil drilling rig, located in the Gulf of Mexico about 41 miles off the Louisiana coast, exploded, burned for two days, and sank. Approximately 4.9 million gallons of crude oil were released and traveled with ocean currents to reach the coasts of Louisiana, Mississippi, Alabama, and Florida. Previous studies have primarily considered the direct impact of oil and dispersant contamination on coastal ecosystems, but have not examined the potential impact of the accident on the inorganic geochemistry of coastal waters and sediments. In this study, microcosm experiments were conducted to determine how oil contamination will affect the concentration and distribution of trace elements in a salt marsh environment. Uncontaminated sediment and seawater, collected from a salt marsh at Bayou la Batre, Alabama, were measured into jars and spiked with 500 ppm MC-252 oil. Twenty jars, including duplicates and both sterile and non-sterile controls, were placed on a shaker table at 100 rpm. The jars were sacrificed at predetermined time intervals (0 h, 6 h, 12 h, 24 h, 48 h, 7 d, and 14 d), and the aqueous samples prepared for analysis by ICP-OES and IC. The pH for the water in the time series experiment ranged from 7.16 to 8.06. Seawater alkalinity was measured at 83.07 mg CaCO3/L. ICP-OES data show variations in aqueous element concentrations over the 14 day microcosm experiment. Significant positive correlations (>0.75) were found for the following pairs of elements: calcium and magnesium, calcium and sodium, magnesium and sodium, silica and boron, beryllium and boron, iron and silica, manganese and silica, boron and manganese, arsenic and nickel, beryllium and selenium, beryllium and zinc, copper and chloride, bromide and sulfate. Aqueous iron concentrations were highly correlated with solution pH. The presence of iron oxide and clays in the sediment indicates a potential for adsorption of trace elements sourced from the environment and from crude oil contamination. The release of aqueous Fe(II) between 2 to 14 days could be caused by desorption from, and/or by reductive dissolution of, iron-bearing clays or iron oxide. Metals associated with crude oil are releasing into the water at similar times. Cadmium and vanadium, metals commonly associated with crude oil, both increase in concentration six hours into the experiment, followed by another small peak after seven days. Other trace elements (nickel, copper, and zinc) are released after one day. Geochemical modeling is being used to interpret the aqueous geochemistry of the experiments.

Rentschler, E. K.; Donahoe, R. J.

2011-12-01

213

Dissolved organic Fe(III) and Fe(II) complexes in salt marsh porewaters  

NASA Astrophysics Data System (ADS)

Fe(III) and Fe(II) organic complexes were determined by spectroscopic methods after sephadex gel fractionation of salt marsh porewaters during June and July 1993. Fe(III), which is a significant anaerobic oxidant for sulfide mineral oxidation, was typically found in the 100-5000 molecular weight (MW) fraction indicative of humic and other organic complexing agents. Fe(II) was found in both the <100 and the 100-5000 MW fractions with most of the Fe(II) found in the smaller MW class. Both forms of Fe precipitated with humic material when the pH of the porewaters became less than 3. There was a twofold decrease in the <5000 MW fractions, a ninefold increase in the >5000 MW class, and a tenfold decrease in dissolved Fe concentration in sephadex gel fractions as the pH decreased from 5.0 to <3 for porewater samples. Low pH values are attributed to sulfide mineral oxidation from severe drought conditions that caused significant dessication of the vegetated marsh. Microelectrode measurements demonstrated that O 2 was not detected below 2 mm and that Fe(III) organic complexes should be significant oxidants in anoxic waters.

Luther, George W.; Shellenbarger, P. Ann; Brendel, Paul J.

1996-03-01

214

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

215

The effect of tidal forcing on biogeochemical processes in intertidal salt marsh sediments  

PubMed Central

Background Early diagenetic processes involved in natural organic matter (NOM) oxidation in marine sediments have been for the most part characterized after collecting sediment cores and extracting porewaters. These techniques have proven useful for deep-sea sediments where biogeochemical processes are limited to aerobic respiration, denitrification, and manganese reduction and span over several centimeters. In coastal marine sediments, however, the concentration of NOM is so high that the spatial resolution needed to characterize these processes cannot be achieved with conventional sampling techniques. In addition, coastal sediments are influenced by tidal forcing that likely affects the processes involved in carbon oxidation. Results In this study, we used in situ voltammetry to determine the role of tidal forcing on early diagenetic processes in intertidal salt marsh sediments. We compare ex situ measurements collected seasonally, in situ profiling measurements, and in situ time series collected at several depths in the sediment during tidal cycles at two distinct stations, a small perennial creek and a mud flat. Our results indicate that the tides coupled to the salt marsh topography drastically influence the distribution of redox geochemical species and may be responsible for local differences noted year-round in the same sediments. Monitoring wells deployed to observe the effects of the tides on the vertical component of porewater transport reveal that creek sediments, because of their confinements, are exposed to much higher hydrostatic pressure gradients than mud flats. Conclusion Our study indicates that iron reduction can be sustained in intertidal creek sediments by a combination of physical forcing and chemical oxidation, while intertidal mud flat sediments are mainly subject to sulfate reduction. These processes likely allow microbial iron reduction to be an important terminal electron accepting process in intertidal coastal sediments.

Taillefert, Martial; Neuhuber, Stephanie; Bristow, Gwendolyn

2007-01-01

216

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

2011-01-01

217

Estimating root lifespan of two grasses at contrasting elevation in a salt marsh by applying vitality staining on roots from in-growth cores  

Microsoft Academic Search

Contrasting soil conditions caused by different inundation frequenciesrequire different root growth strategies along the elevational gradient ofcoastal salt marshes. The objective of this study was to examine (1) if rootlifespan was shorter in Elymus pycnanthus, a relativelyfast-growing competitive species dominating high marshes, than inSpartina anglica, a relatively slow-growingstress-tolerating species dominating low marshes, and (2) if the species withlonger lifespan had

Tjeerd J. Bouma; K. Hengst; B. P. Koutstaal; J. van Soelen

2003-01-01

218

Functional gene pyrosequencing and network analysis: an approach to examine the response of denitrifying bacteria to increased nitrogen supply in salt marsh sediments  

PubMed Central

Functional gene pyrosequencing is emerging as a useful tool to examine the diversity and abundance of microbes that facilitate key biogeochemical processes. One such process, denitrification, is of particular importance because it converts fixed nitrate (NO?3) to N2 gas, which returns to the atmosphere. In nitrogen limited salt marshes, removal of NO?3 prior to entering adjacent waters helps prevent eutrophication. Understanding the dynamics of salt marsh microbial denitrification is thus imperative for the maintenance of healthy coastal ecosystems. We used pyrosequencing of the nirS gene to examine the denitrifying community response to fertilization in experimentally enriched marsh plots. A key challenge in the analysis of sequence data derived from pyrosequencing is understanding whether small differences in gene sequences are ecologically meaningful. We applied a novel approach from information theory to determine that the optimal similarity level for clustering DNA sequences into OTUs, while still capturing the ecological complexity of the system, was 88%. With this clustering, phylogenetic analysis yielded 6 dominant clades of denitrifiers, the largest of which, accounting for more than half of all the sequences collected, had no close cultured representatives. Of the 638 OTUs identified, only 11 were present in all plots and no single OTU was dominant. We did, however, find a large number of specialist OTUs that were present only in a single plot. The high degree of endemic OTUs, while accounting for a large proportion of the nirS diversity in the plots, were found in lower abundance than the generalist taxa. The proportion of specialist taxa increased with increasing supply of nutrients, suggesting that addition of fertilizer may create conditions that expand the niche space for denitrifying organisms and may enhance the genetic capacity for denitrification.

Bowen, Jennifer L.; Byrnes, Jarrett E. K.; Weisman, David; Colaneri, Cory

2013-01-01

219

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...

220

Net ecosystem methane and carbon dioxide exchanges in a Lake Erie coastal marsh and a nearby cropland  

NASA Astrophysics Data System (ADS)

ecosystem carbon dioxide (FCO2) and methane (FCH4) exchanges were measured by using the eddy covariance method to quantify the atmospheric carbon budget at a Typha- and Nymphaea-dominated freshwater marsh (March 2011 to March 2013) and a soybean cropland (May 2011 to May 2012) in northwestern Ohio, USA. Two year average annual FCH4 (49.7 g C-CH4 m-2 yr-1) from the marsh was high and compatible with its net annual CO2 uptake (FCO2: -21.0 g C-CO2 m-2 yr-1). In contrast, FCH4 was small (2.3 g C-CH4 m-2 yr-1) and accounted for a minor portion of the atmospheric carbon budget (FCO2: -151.8 g C-CO2 m-2 yr-1) at the cropland. At the seasonal scale, soil temperature associated with methane (CH4) production provided the dominant regulator of FCH4 at the marsh (R2 = 0.86). At the diurnal scale, plant-modulated gas flow was the major pathway for CH4 outgassing in the growing season at the marsh. Diffusion and ebullition became the major pathways in the nongrowing season and were regulated by friction velocity. Our findings highlight the importance of freshwater marshes for their efficiency in turning over and releasing newly fixed carbon as CH4. Despite marshes accounting for only ~4% of area in the agriculture-dominated landscape, their high FCH4 should be carefully addressed in the regional carbon budget.

Chu, Housen; Chen, Jiquan; Gottgens, Johan F.; Ouyang, Zutao; John, Ranjeet; Czajkowski, Kevin; Becker, Richard

2014-05-01

221

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

222

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

223

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

224

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

225

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

226

Relationships between vegetation and environmental characteristics in a salt-marsh system on the coast of Northwest Spain  

Microsoft Academic Search

This study reports an investigation of relationships between environmental variables (electrical conductivity of groundwater, soil redox potential, water-table depth, and high-tide flooding depth) on vegetation zonation in a salt-marsh system on the coast of northwest Spain. Discriminant analysis indicated that conductivity (a measure of salinity) and redox potential are correlated with vegetation type within the study area. Conductivity declines with

J. M. Sánchez; X. L. Otero; J. Izco

1998-01-01

227

A comparison of physicochemical variables across plant zones in a mangal\\/salt marsh community in Louisiana  

Microsoft Academic Search

Three vegetation zones were delineated in a mangal \\/ salt marsh community at Bay Champagne, Louisiana — a zone dominated byAvicennia germinans adjacent to the bay, an inland zone dominated bySpartina alterniflora, and a transition zone between the two containing both species. Parallel transects that intersected each zone were established\\u000a perpendicular to the shore of the bay and sampled to

C. Stuart Patterson; Irving A. Mendelssohn

1991-01-01

228

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

229

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

230

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

231

Vesicular arbuscular mycorrhiza (VAM) in pioneer salt marsh plants of the Ganges river delta in West Bengal (India)  

Microsoft Academic Search

VA mycorrhizal colonization of four species of pioneer salt marsh plants including two species of chenopodiaceae at the terminal\\u000a Gangetic delta in India, is reported. Five common species of VAM fungi were recorded from rhizosphere soils of the plant species.\\u000a Population of spores of VAM fungi and effective inoculum potential of these fungi in rhizosphere soils as determined by the

A. Sengupta; S. Chaudhuri

1990-01-01

232

High Tolerance to Salinity and Herbivory Stresses May Explain the Expansion of Ipomoea Cairica to Salt Marshes  

PubMed Central

Background Invasive plants are often confronted with heterogeneous environments and various stress factors during their secondary phase of invasion into more stressful habitats. A high tolerance to stress factors may allow exotics to successfully invade stressful environments. Ipomoea cairica, a vigorous invader in South China, has recently been expanding into salt marshes. Methodology/Principal Findings To examine why this liana species is able to invade a stressful saline environment, we utilized I. cairica and 3 non-invasive species for a greenhouse experiment. The plants were subjected to three levels of salinity (i.e., watered with 0, 4 and 8 g L?1 NaCl solutions) and simulated herbivory (0, 25 and 50% of the leaf area excised) treatments. The relative growth rate (RGR) of I. cairica was significantly higher than the RGR of non-invasive species under both stress treatments. The growth performance of I. cairica was not significantly affected by either stress factor, while that of the non-invasive species was significantly inhibited. The leaf condensed tannin content was generally lower in I. cairica than in the non-invasive I. triloba and Paederia foetida. Ipomoea cairica exhibited a relatively low resistance to herbivory, however, its tolerance to stress factors was significantly higher than either of the non-invasive species. Conclusions/Significance This is the first study examining the expansion of I. cairica to salt marshes in its introduced range. Our results suggest that the high tolerance of I. cairica to key stress factors (e.g., salinity and herbivory) contributes to its invasion into salt marshes. For I. cairica, a trade-off in resource reallocation may allow increased resources to be allocated to tolerance and growth. This may contribute to a secondary invasion into stressful habitats. Finally, we suggest that I. cairica could spread further and successfully occupy salt marshes, and countermeasures based on herbivory could be ineffective for controlling this invasion.

Liu, Gang; Huang, Qiao-Qiao; Lin, Zhen-Guang; Huang, Fang-Fang; Liao, Hui-Xuan; Peng, Shao-Lin

2012-01-01

233

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

234

Primary productivity of angiosperm and macroalgae dominated habitats in a New England Salt Marsh: a Comparative analysis  

NASA Astrophysics Data System (ADS)

Net primary productivity estimates were made for the major macrophyte dominated habitats of the Nauset Marsh system, Cape Cod, Massachusetts. Above-ground primary productivity of short form Spartina alterniflora, the dominant habitat of the system, was 664 g m -2 y -1. Productivity of the other dominant angiosperm ( Zostera marina) was estimated to range from 444-987 g m -2 y -1. The marsh creekbank habitat was dominated by an intertidal zone of fucoid algae ( Ascophyllum nodosum ecad. scorpioides, 1179 g m -2 y -1; Fucus vesiculosus, 426 g m -2 y -1), mixed intertidal filamentous algae (91 g m -2 y -1), and a subtidal zone of assorted macroalgae (68 g m -2 y -1). Intertidal mudflats were dominated by Cladophora gracilis, with net production ranging from 59-637 g m -2 y -1. These angiosperm and macrophyte and macrophyte dominated habitats produce over 3 × 10 6 kg y -1 of biomass (1·2 × 10 6 kg carbon y -1). Twenty-eight per cent (28%) of this carbon production is derived from the Zostera and macroalgae habitats. Although S. alterniflora is considered the major macrophyte primary producer in Nauset Marsh and other north temperate salt marshes, it is concluded that other habitats also contribute significantly to total system carbon production.

Roman, C. T.; Able, K. W.; Lazzari, M. A.; Heck, K. L.

1990-01-01

235

Influence of flooding and vegetation on carbon, nitrogen, and phosphorus dynamics in the pore water of a Spartina alterniflora salt marsh.  

PubMed

Four sites were selected in a salt marsh in the Bahia Blanca Estuary (Argentina): (1) low marsh (flooded by the tide twice daily) vegetated by S. alterniflora; (2) non-vegetated low marsh; (3) high marsh (flooded only in spring tides) vegetated by S. alterniflora; (4) non-vegetated high marsh. The pH and Eh were measured in sediments, while dissolved nutrients (ammonium, nitrate, nitrite and phosphate) and particulate organic matter (POM) were determined in pore water. pH (6.2-8.7) was only affected by vegetation in low areas. Eh (from -300 to 250 mV) was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POM concentration was greater in the high marsh than in the low marsh, with no effect of vegetation. Ammonium was the most abundant nitrogen nutrient species in pore water, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were affected by both flooding and vegetation. Phosphate was always present in pore water at all sites throughout the year and its concentration varied within narrow limits, with no effect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the pore water composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment pore water. PMID:21516994

Negrin, Vanesa L; Spetter, Carla V; Asteasuain, Raúl O; Perillo, Gerardo M E; Marcovecchio, Jorge E

2011-01-01

236

Stratigraphy and geologic history of a southeastern salt marsh basin, North Inlet, South Carolina, USA  

Microsoft Academic Search

Forty seven vibracores and fifteen radiocarbon dates have beenobtained to outline the Holocene history of the North Inlet saltmarsh basin. Marsh deposits date from about 3500 years BP and havetransgressed over a Late Pleistocene beach-ridge terrain that waspartly eroded by Late Holocene tidal channel meandering. Marsh mudalso has prograded southward over shallow subtidal estuarine Macomamuds which date from about 4500

Leonard Robert Gardner; Dwayne E. Porter

2001-01-01

237

Contrasting patterns of phytoplankton community pigment composition in two salt marsh estuaries in southeastern United States.  

PubMed

Phytoplankton community pigment composition and water quality were measured seasonally along salinity gradients in two minimally urbanized salt marsh estuaries in South Carolina in order to examine their spatial and temporal distributions. The North Inlet estuary has a relatively small watershed with minimal fresh water input, while the Ashepoo, Combahee, and Edisto (ACE) Basin is characterized by a relatively greater influence of riverine drainage. Sampling stations were located in regions of the estuaries experiencing frequent diurnal tidal mixing and had similar salinity and temperature regimens. Phytoplankton community pigment composition was assessed by using high-performance liquid chromatography (HPLC) and multivariate statistical analyses. Shannon diversity index, principal-component, and cluster analyses revealed that phytoplankton community pigments in both estuaries were seasonally variable, with similar diversities but different compositions. The temporal pigment patterns indicated that there was a relatively weak correlation between the pigments in ACE Basin and the relative persistence of photopigment groups in North Inlet. The differences were presumably a consequence of the unpredictability and relatively greater influence of river discharge in the ACE Basin, in contrast to the greater environmental predictability of the more tidally influenced North Inlet. Furthermore, the timing, magnitude, and pigment composition of the annual phytoplankton bloom were different in the two estuaries. The bloom properties in North Inlet reflected the predominance of autochthonous ecological control (e.g., regenerated nutrients, grazing), and those in ACE Basin suggested that there was greater influence of allochthonous environmental factors (e.g., nutrient loading, changes in turbidity). These interestuarine differences in phytoplankton community structure and control provide insight into the organization of phytoplankton in estuaries. PMID:12839791

Noble, Peter A; Tymowski, Raphael G; Fletcher, Madilyn; Morris, James T; Lewitus, Alan J

2003-07-01

238

The inner filter effects and their correction in fluorescence spectra of salt marsh humic matter.  

PubMed

The inner filter effects in synchronous fluorescence spectra (??=60 nm) of sedimentary humic substances from a salt marsh were studied. Accordingly to their type and the influence of plant colonization, these humic substances have different spectral features and the inner filter effects act in a different manner. The fluorescence spectra of the humic substances from sediments with colonizing plants have a protein like band (?exc=280 nm) which is strongly affected by primary and secondary inner filter effects. These effects were also observed for the bands situated at longer wavelengths, i.e., at ?exc=350 nm and ?ex=454 nm for the fulvic acids (FA) and humic acids (HA), respectively. However, they are more important for the band at 280 nm, causing spectral distortions which can be clearly seen when the spectra of solutions 40 mg L(-1) of different samples (Dissolved Organic Carbon - DOC~20 mg L(-1)) are compared with and without correction of the inner filter effects. The importance of the spectral distortions caused by inner filter effects has been demonstrated in solutions containing a mixture of model compounds which represent the fluorophores detected in the spectra of sedimentary humic samples. The effectiveness of the mathematical correction of the inner filter effects in the spectra of those solutions and of solutions of sedimentary humic substances was studied. It was observed that inner filter effects in the sedimentary humic substances spectra can be mathematically corrected, allowing to obtain a linear relationship between the fluorescence intensity and humic substances concentration and preventing distortions at concentrations as high as 50 mg L(-1) which otherwise would obscure the protein like band. PMID:23845487

Mendonça, Ana; Rocha, Ana C; Duarte, Armando C; Santos, Eduarda B H

2013-07-25

239

Growth and Photosynthetic Responses to Salinity of the Salt-marsh Shrub Atriplex portulacoides  

PubMed Central

Background and Aims Atriplex (Halimione) portulacoides is a halophytic, C3 shrub. It is virtually confined to coastal salt marshes, where it often dominates the vegetation. The aim of this study was to investigate its growth responses to salinity and the extent to which these could be explained by photosynthetic physiology. Methods The responses of young plants to salinity in the range 0–700 mol m?3 NaCl were investigated in a glasshouse experiment. The performance of plants was examined using classical growth analysis, measurements of gas exchange (infrared gas analysis), determination of chlorophyll fluorescence characteristics (modulated fluorimeter) and photosynthetic pigment concentrations; total ash, sodium, potassium and nitrogen concentrations, and relative water content were also determined. Key Results Plants accumulated Na+ approximately in proportion to external salinity. Salt stimulated growth up to an external concentration of 200 mol m?3 NaCl and some growth was maintained at higher salinities. The main determinant of growth response to salinity was unit leaf rate. This was itself reflected in rates of CO2 assimilation, which were not affected by 200 mol m?3 but were reduced at higher salinities. Reductions in net photosynthetic rate could be accounted for largely by lower stomatal conductance and intercellular CO2 concentration. Apart from possible effects of osmotic shock at the beginning of the experiment, salinity did not have any adverse effect on photosystem II (PSII). Neither the quantum efficiency of PSII (?PSII) nor the chlorophyll fluorescence ratio (Fv/Fm) were reduced by salinity, and lower mid-day values recovered by dawn. Mid-day Fv/Fm was in fact depressed more at low external sodium concentration, by the end of the experiment. Conclusions The growth responses of the hygro-halophyte A. portulacoides to salinity appear largely to depend on changes in its rate of photosynthetic gas exchange. Photosynthesis appears to be limited mainly through stomatal conductance and hence intercellular CO2 concentration, rather than by effects on PSII; moderate salinity might stimulate carboxylation capacity. This is in contrast to more extreme halophytes, for which an ability to maintain leaf area can partially offset declining rates of carbon assimilation at high salinity.

Redondo-Gomez, Susana; Mateos-Naranjo, Enrique; Davy, Anthony J.; Fernandez-Munoz, Francisco; Castellanos, Eloy M.; Luque, Teresa; Figueroa, M. Enrique

2007-01-01

240

Characterization of the indigenous PAH-degrading bacteria of Spartina dominated salt marshes in the New York\\/New Jersey Harbor  

Microsoft Academic Search

The aerobic polyaromatic hydrocarbon (PAH) degrading microbial communities of two petroleum-impacted Spartina-dominated salt marshes in the New York\\/New Jersey Harbor were examined using a combination of microbiological, molecular\\u000a and chemical techniques. Microbial isolation studies resulted in the identification of 48 aromatic hydrocarbon-degrading bacterial\\u000a strains from both vegetated and non-vegetated marsh sediments. The majority of the isolates were from the genera

L. A. Launen; J. Dutta; R. Turpeinen; M. E. Eastep; R. Dorn; V. H. Buggs; J. W. Leonard; M. M. Häggblom

2008-01-01

241

The effect of macrofauna, meiofauna and microfauna on the degradation of Spartina maritima detritus from a salt marsh area  

NASA Astrophysics Data System (ADS)

Decomposition of salt marsh plants results from physical, chemical and biological processes including abiotic and biotic fragmentation, microbial decay and chemical transformation. According to literature data, only a few species have the ability to feed directly on living plant material, so fungi and bacteria seem to be the principal competitors for the organic substrates. Nevertheless, by consuming bacteria, protists and fungi associated to the detritus, macrofauna and meiofauna recycle the incorporated nutrients. Moreover, this nutrient regeneration may be seen as an effective factor in maintaining and stimulating bacterial production. In fact, it is well known that many detritus feeding species have very low assimilation efficiencies. The objective of the present study was to compare the nutrient mass balance of carbon; nitrogen and phosphorus in Spartina maritima covered areas and bare bottom sediment, with and without contribution of macrofauna, meiofauna and microbial populations. Nutrients mass balance was studied taking into account the initial and final nutrient concentrations in the sediment, water and plant material. Faunal activity was measured as a function of remineralised carbon, nitrogen and phosphorus. The experimental set-up included sixteen sub-experiments, which varied with respect to type of fauna, plant biomass and oxic status. Each sub-experiment was performed in small glass containers (3 L) containing about 900 g wwt sediment and 2.5 L estuarine water. Plant material, cut from intact plants, sediment cores and estuarine water were brought from the southern arm of the Mondego estuary (Portugal). The results showed that although the bacterial activity was responsible for the Spartina maritima degradation, the presence of meiofauna and macrofauna significantly enhanced the process. Moreover, the presence of Spartina maritima positively affected the mineralisation of the sediment carbon and nitrogen, especially when the three faunal components were present, and denitrification rates were highest in the presence of the macrofauna and meiofauna. The present study suggests that macrofauna and meiofauna have an important role on the ecosystem nutrient flux and that fauna might function as a sink for excess nutrients, that otherwise could be exported to the coastal waters.

Lillebø, Ana Isabel; Flindt, Mogens R.; Pardal, Miguel Ângelo; Marques, João Carlos

1999-07-01

242

ABOVE- AND BELOWGROUND EMERGENT MACROPHYTE PRODUCTION AND TURNOVER IN A COASTAL MARSH ECOSYSTEM, GEORGIA  

EPA Science Inventory

Seasonal patterns of aboveground plant mass and the depth distribution of live roots, rhizomes, and dead belowground organic matter were measured for Spartina alterniflora and Spartina cynosuroides in Georgia tidal marshes. Peak live aboveground biomass was 1.6x higher for S. cyn...

243

Carbon-13 nuclear magnetic resonance analysis, lignin content and carbohydrate composition of humic substances from salt marsh estuaries  

NASA Astrophysics Data System (ADS)

13C nuclear magnetic resonance spectroscopy, CuO oxidation products of lignin and hydrolyzable carbohydrates were measured for fulvic and humic acids extracted from living and dead Spartina alterniflora and salt marsh sediments. With these methods, there was little evidence for early diagenetic alteration of the humic materials. No trends consistent for fulvic and humic acids were observed for either hydrolyzable carbohydrates or lignin derived phenols, and chemical measurements of these fractions did not agree with spectral estimates. Humic acids appear to contain secondary amide linkages typical of proteins and peptides.

Alberts, James J.; Hatcher, Patrick G.; Price, Mary T.; Filip, Zdenek

244

The restoration potential of the Mesopotamian marshes of Iraq.  

PubMed

Uncontrolled releases of Tigris and Euphrates River waters after the 2003 war have partially restored some former marsh areas in southern Iraq, but restoration is failing in others because of high soil and water salinities. Nearly 20% of the original 15,000-square-kilometer marsh area was reflooded by March 2004, but the extent of marsh restoration is unknown. High-quality water, nonsaline soils, and the densest native vegetation were found in the only remaining natural marsh, the Al-Hawizeh, located on the Iranian border. Although substantially reduced in area and under current threat of an Iranian dike, it has the potential to be a native repopulation center for the region. Rapid reestablishment, high productivity, and reproduction of native flora and fauna in reflooded former marsh areas indicate a high probability for successful restoration, provided the restored wetlands are hydraulically designed to allow sufficient flow of noncontaminated water and flushing of salts through the ecosystem. PMID:15731454

Richardson, Curtis J; Reiss, Peter; Hussain, Najah A; Alwash, Azzam J; Pool, Douglas J

2005-02-25

245

Ecosystem metabolism in a temporary Mediterranean marsh (Doñana National Park, SW Spain)  

NASA Astrophysics Data System (ADS)

The metabolic balance of the open waters supporting submerged macrophytes of the Doñana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community (benthic + pelagic) was net autotrophic with net community production rates averaging 0.61 g C m-2 d-1, and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic ranging from 42 to 255 ?E m-2 s-1, with net heterotrophic at lower irradiance. Examination of the contributions of the benthic and the pelagic compartments showed the pelagic compartment to be strongly heterotrophic (average P/R ratio = 0.27), indicating that the metabolism of the pelagic compartment is highly subsidised by excess organic carbon produced in the strongly autotrophic benthic compartment (average P/R = 1.58).

Geertz-Hansen, O.; Montes, C.; Duarte, C. M.; Sand-Jensen, K.; Marbá, N.; Grillas, P.

2011-04-01

246

Recent environmental evolution of regenerated salt marshes in the southern Bay of Biscay: Anthropogenic evidences in their sedimentary record  

NASA Astrophysics Data System (ADS)

Short sediment cores (up to 44 cm long) taken from salt marshes regenerated during the last 60 years in the Urdaibai Biosphere Reserve have been interpreted on the basis of microfaunal and geochemical determinations and historical data. Agricultural soils in the middle and upper estuary reaches were abandoned during the 1950s and entrance of estuarine water provoked a rapid natural environmental transformation of these anthropogenic areas. Increasing amounts of sand and benthic foraminifera were deposited at a very high sedimentation rate (average 16 mm yr-1) during the 1950s and 1960s allowing well developed regenerated salt marshes to be rapidly established in these formerly occupied areas. During recent decades much lower sedimentation rates (average 2.5 mm yr-1), abundant agglutinated foraminiferal assemblages and enrichment of heavy metals (Pb, Zn, Cu, Ni and Cr) due to industrialization are characteristic of these already regenerated environments. This rapid regeneration process (less than 10 years) is of great interest for environmental management of modern coastal zones where extensive reclaimed land could be easily restored to tidal wetlands under the current scenario of accelerating sea-level rise.

Cearreta, A.; García-Artola, A.; Leorri, E.; Irabien, M. J.; Masque, P.

2013-01-01

247

Role of stratigraphy in governing pore water seepage from salt marsh sediments  

Microsoft Academic Search

Numerical modeling experiments have been used to study the effects of marsh stratigraphy on the seepage of pore water into tidal channels. If the mud-sand contact lies at the elevation of the channel bottom and the hydraulic conductivity of the basal sand is at least an order of magnitude greater than the overlying mud, the locus of maximum seepage shifts

Leonard Robert Gardner

2007-01-01

248

Cadmium and mercury-resistant Bacillus strains from a salt marsh and from Boston Harbor  

Microsoft Academic Search

Bacteria resistant to cadmium or mercury or both were isolated from the Great Sippewissett Marsh (Cape Cod, Mass.) and from Boston Harbor. Many of these metal-resistant isolates were gram-positive aerobic sporeformers, although not necessarily isolated as spores. Although several of the isolated strains bore plasmids, cadmium and mercury resistances appeared to be, for the most part, chromosomally encoded. DNA sequence

I. Mahler; H. S. Levinson; Y. Wang; H. O. Halvorson

1986-01-01

249

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

PubMed Central

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 13C-depleted petroleum to monitor changes in the 13C content of biomass. Magnetic bead capture methods for selective recovery of bacterial RNA were used to monitor the 13C content of bacterial biomass during a 2-week experiment. The data show that by the end of the experiment, up to 26% of bacterial biomass was derived from consumption of the freshly spilled oil. The results contrast with the inertness of a nearby relict spill, which occurred in 1969 in West Falmouth, MA. Sequences of 16S rRNA genes from our experimental samples also were consistent with previous reports suggesting the importance of Gamma- and Deltaproteobacteria and Firmicutes in the remineralization of hydrocarbons. The magnetic bead capture approach makes it possible to quantify uptake of petroleum hydrocarbons by microbes in situ. Although employed here at the domain level, RNA capture procedures can be highly specific. The same strategy could be used with genus-level specificity, something which is not currently possible using the 13C content of biomarker lipids.

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

2008-01-01

250

Geochemical survey and metal bioaccumulation of three bivalve species ( Crassostrea gigas, Cerastoderma edule and Ruditapes philippinarum) in the Nord Médoc salt marshes (Gironde estuary, France)  

Microsoft Academic Search

A 15-month experiment combining a geochemical survey of Cd, Cu, Zn and Hg with a bioaccumulation study for three filter-feeding bivalve species (oysters, Crassostrea gigas; cockles, Cerastoderma edule; and clams, Ruditapes philippinarum) was conducted in a breeding basin of the Nord Médoc salt marshes connected to the Gironde estuary, which is affected by historic polymetallic pollution. Regular manual surface measurements

M. Baudrimont; J. Schäfer; V. Marie; R. Maury-Brachet; C. Bossy; A. Boudou; G. Blanc

2005-01-01

251

Hydrologic forcing of submarine groundwater discharge: Insight from a seasonal study of radium isotopes in a groundwater-dominated salt marsh estuary  

Microsoft Academic Search

A seasonal study of radium-derived submarine groundwater discharge (SGD) and associated nitrogen fluxes was carried out in a salt marsh estuary between 2001 and 2003 (Pamet River Estuary, Massachusetts). Twelve- hour time series of salinity and radium at the estuary inlet were used to determine the relative importance of fresh versus saline SGD, respectively. The distinct radium (228Ra: 226Ra) isotopic

Matthew A. Charette

2007-01-01

252

Composition and Adult Activity of Salt-Marsh Mosquitoes Attracted to 1- Octen-3-OL, Carbon Dioxide, and Light in Topsail Island, North Carolina. Scientific Note.  

National Technical Information Service (NTIS)

By monitoring weekly for 3 months with Centers for Disease Control (CDC) light traps baited with carbon dioxide (CO2) and light, 12 species of mosquitoes were collected from salt-marsh areas in Topsail Island, North Carolina: Aedes vexans, Anopheles atrop...

L. M. Rueda R. C. Gardner

2003-01-01

253

The Amoco Cadiz Oil Spill: Evolution of Petroleum Hydrocarbons in the Ile Grande Salt Marshes (Brittany) after a 13-year Period  

Microsoft Academic Search

The Ile Grande salt marshes (Brittany coast) were polluted by petroleum hydrocarbons after theAmoco Cadizgrounding in 1978. Thirteen years after the oil spill, sediments were analysed for residual hydrocarbons in order to monitor the aliphatic and aromatic hydrocarbon signatures and to assess both qualitatively and quantitatively the changes in composition of theAmoco Cadizoil. Six stations were selected in the Ile

G. Mille; D. Munoz; F. Jacquot; L. Rivet; J.-C. Bertrand

1998-01-01

254

Effects of sustained-release methoprene and a combined formulation of liquid methoprene and Bacillus thuringiensis israelensis on insects in salt marshes.  

PubMed

Aquatic insects are an important component of the food web in salt marshes, therefore it is necessary to test whether pesticides used to control mosquitoes in salt marshes are safe for nontarget insects. We tested the nontarget effects of a combined formulation (duplex) of Bacillus thuringiensis israelensis (B.t.i.) and liquid methoprene (an insect development regulator) or sustained-release methoprene pellets (Altosid(R) pellets) by applying these materials to replicated salt marsh ponds at maximum label rates. Untreated ponds served as controls. We measured effects of the pesticides by rearing immature mosquitoes (Aedes dorsalis) and water boatmen (Trichocorixa reticulata) in predator-exclusion cages and by monitoring uncaged populations of invertebrates using replicated sweep-net samples. Both pesticides killed caged mosquitoes, and the activity of the Altosid(R) pellets continued through 99 days. There were no detectable effects of either pesticide on the survival or maturation of T. reticulata, or on abundances of uncaged invertebrates. The long-term activity of the pellets could help minimize mosquito abatement activity in salt marshes where there are breeding birds or endangered species. However, other studies suggest that this advantage needs to be balanced against the risks that sustained-release formulations could lead to development of resistance in mosquitoes or that initially undetected nontarget effects could build over time. PMID:10871420

Lawler, S P; Dritz, D A; Jensen, T

2000-08-01

255

Draft Genome Sequence of the Obligate Halophilic Bacillus sp. Strain NSP22.2, Isolated from a Seasonal Salt Marsh of the Great Rann of Kutch, India  

PubMed Central

Here, we report the 4.0-Mbp draft genome of an obligate halophile, Bacillus sp. strain NSP22.2, isolated from a seasonal salt marsh of the Great Rann of Kutch, India. To understand the mechanism(s) of obligate halophilism and to isolate the relevant gene(s), the genome of Bacillus sp. NSP22.2 was sequenced.

Pal, Kamal Krishna; Sherathia, Dharmesh; Vanpariya, Sejal; Patel, Ilaxi; Dalsania, Trupti; Savsani, Kinjal; Sukhadiya, Bhoomika; Mandaliya, Mona; Thomas, Manesh; Ghorai, Sucheta; Rupapara, Rupal; Rawal, Priya

2013-01-01

256

Structural Data for the Columbus Salt Marsh Geothermal Area - GIS Data  

DOE Data Explorer

Shapefiles and spreadsheets of structural data, including attitudes of faults and strata and slip orientations of faults. - Detailed geologic mapping of ~30 km2 was completed in the vicinity of the Columbus Marsh geothermal field to obtain critical structural data that would elucidate the structural controls of this field. - Documenting E? to ENE?striking left lateral faults and N? to NNE?striking normal faults. - Some faults cut Quaternary basalts. - This field appears to occupy a displacement transfer zone near the eastern end of a system of left?lateral faults. ENE?striking sinistral faults diffuse into a system of N? to NNE?striking normal faults within the displacement transfer zone. - Columbus Marsh therefore corresponds to an area of enhanced extension and contains a nexus of fault intersections, both conducive for geothermal activity.

James E. Faulds

257

Marsh nutrient export supplied by groundwater discharge: Evidence from radium measurements  

NASA Astrophysics Data System (ADS)

We use 228Ra and 226Ra to determine the mass balance of dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) in the North Inlet salt marsh-estuarine system. While this system has only minor freshwater inputs of nutrients or radium, it is an extremely productive ecosystem. In addition, there are significant exports of these dissolved species to the coastal ocean. Saline groundwater in this estuarine system contains nutrient and radium concentrations more than an order of magnitude greater than surface waters. Using a radium mass balance, we estimate the groundwater discharge necessary to support the export of radium to the coastal ocean and the corresponding flux of nutrients from the groundwater. From these calculations, we show that the underlying aquifer supplies nutrients sufficient to support the net primary productivity of the salt marsh ecosystem and to account for the known export of nutrients from the marsh. We conclude that the major nutrient source to the North Inlet, South Carolina, salt marsh is the saline aquifer lying just beneath the surface of the marsh. Furthermore, extrapolation of the nutrient export to include other South Carolina marshes suggests that nutrient fluxes from salt marshes to the coastal ocean rival riverine nutrient fluxes for the region.

Krest, J. M.; Moore, W. S.; Gardner, L. R.; Morris, J. T.

2000-03-01

258

Sulfur enrichment of humic substances in a Delaware salt marsh sediment core  

NASA Astrophysics Data System (ADS)

Humic sulfur, operationally defined as the sulfur extracted with humic substances in 0. l N NaOH solution, comprises up to 51% of the total sulfur inventory in a sediment core taken from a Delaware Spartina alterniflora marsh. Pyrite sulfur is the next largest fraction, except at the near-surface sediments, where zerovalent sulfur concentrations are significant. X-ray photoelectron spectroscopy indicates that the humic sulfur consists of sulfoxides or sulfones and, in a more reduced state, organic sulfides and/or organic polysulfides. A subsurface decrease in the humic acid C:S atomic ratio to 56 ± 2 suggests that the upper 4 cm of marsh sediment is the locus for humic sulfur formation. S. alterniflora detritus and microbial biomass cannot fully account for observed sulfur enrichment of humic C:S atomic ratios. Therefore, the enrichment of humic substances by sulfur is probably via reaction of reduced sulfur compounds with organic matter. A humic sulfur formation rate of 10.6 ?mol S · cm -3 · a -1 is calculated for the surface sediments and leads to an areal production of 18 ?mol S · cm -2 · a -1 of humic sulfur. Humic sulfur formation and preservation is enhanced by the limited availability of iron for the rapid precipitation of iron sulfide minerals and the apparent resistance of organic sulfur compounds towards reoxidation to sulfate, especially in the upper 9 cm of marsh sediment where inorganic sulfur compounds are rapidly oxidized.

Ferdelman, Timothy G.; Church, Thomas M.; Luther, George W., III

1991-04-01

259

Altered feeding habits and strategies of a benthic forage fish (Fundulus heteroclitus) in chronically polluted tidal salt marshes.  

PubMed

Responses in feeding ecology of a benthic forage fish, mummichogs (Fundulus heteroclitus), to altered prey resources were investigated in chronically polluted salt marshes (the Arthur Kill-AK, New York, USA). The diet niche breadth of the AK populations of mummichogs was significantly lower than that of the reference population, reflecting reduced benthic macroinfaunal species diversity. Most of the AK populations also had 2-3 times less food in their gut than the reference population. This disparity in gut fullness among the populations appeared to be partly due to ingested prey size shifts; some of the AK populations ingested fewer large prey than the reference population. Furthermore, benthic assemblages were strongly associated with sediment-associated mercury; gut fullness of the AK populations also significantly decreased with increasing mercury body burdens. These results indicate that chronic pollution may have directly (chemical bioaccumulation) and indirectly (reduced prey availability) altered the feeding ecology of mummichogs. PMID:21726897

Goto, Daisuke; Wallace, William G

2011-07-01

260

Network analysis of the South Florida Everglades graminoid marshes and comparison with nearby cypress ecosystems  

Microsoft Academic Search

Network analysis (NA) is used to compare two ecosystems with different spatial extents to understand the different patterns and dynamics that arise. NA allows one to study the system at different scales: At the level of bilateral interactions, input-output structure matrices are calculated to look at the direct and indirect effects that one flow has on another; at the functional

J. J Heymans; R. E Ulanowicz; C Bondavalli

2002-01-01

261

Degradation of fuel oil in salt marsh soils affected by the Prestige oil spill.  

PubMed

We assessed natural degradation of fuel oil in three marshes from Galicia (Spain) affected by the Prestige oil spill (Baldaio, Barizo, and Muxía). Soil samples collected from polluted and unpolluted areas on four different dates were used to determine total petroleum hydrocarbon content and fuel-oil components. Natural degradation was monitored by analysing changes in the proportion of saturated hydrocarbons, aromatics, asphaltenes and resins in the soils, and also by evaluating the degree of depletion of saturated hydrocarbons on each sampling date. We additionally assessed the phytoremediation potential of Lolium perenne, L., Convolvulus arvensis L. and Raphanus raphanistrum L. All marsh soils exhibited natural degradation of saturated and aromatic hydrocarbons to between 85 and 95% in most cases. In contrast, asphaltenes and resins were degraded to a lesser extent (viz. 64-76% in Barizo 1, Muxía and Traba; 39-44% in Baldaio; and only 12% in Barizo 2, where flooding by the river continues to introduce balls of fuel oil into the soil). Monitoring analyses revealed natural degradation to be dependent on the thickness of the pollutant layer. Field plots sown with L. perenne L. exhibited no significant differences in fuel-oil degradation from untreated plots. PMID:19157704

Vega, Flora A; Covelo, Emma F; Reigosa, Manuel J; Andrade, María Luisa

2009-07-30

262

Impacts and recovery of the Deepwater Horizon oil spill on vegetation structure and function of coastal salt marshes in the northern Gulf of Mexico.  

PubMed

We investigated the impacts of the Deepwater Horizon (DWH) oil spill on two dominant coastal saltmarsh plants, Spartina alterniflora and Juncus roemerianus, in the northern Gulf of Mexico and the processes controlling differential species-effects and recovery. Seven months after the Macondo MC 252 oil made landfall along the shoreline salt marshes of northern Barataria Bay, Louisiana, concentrations of total petroleum hydrocarbons in the surface 2 cm of heavily oiled marsh soils were as high as 510 mg g(-1). Heavy oiling caused almost complete mortality of both species. However, moderate oiling impacted Spartina less severely than Juncus and, relative to the reference marshes, had no significant effect on Spartina while significantly lowering live aboveground biomass and stem density of Juncus. A greenhouse mesocosm study supported field results and indicated that S. alterniflora was much more tolerant to shoot oil coverage than J. roemerianus. Spartina recovered from as much as 100% oil coverage of shoots in 7 months; however, Juncus recovered to a much lesser extent. Soil-oiling significantly affected both species. Severe impacts of the Macondo oil to coastal marsh vegetation most likely resulted from oil exposure of the shoots and oil contact on/in the marsh soil, as well as repeated oiling events. PMID:22369124

Lin, Qianxin; Mendelssohn, Irving A

2012-04-01

263

Variability and convergence in benthic communities in created salt marshes transitioning into mangrove habitats  

EPA Science Inventory

Wetland creation, enhancement, and restoration activities are commonly implemented to compensate for wetland loss or degradation in coastal ecosystems. Although assessments of structural condition are commonly used to monitor habitat restoration effectiveness, functional equivale...

264

Quarternary Deformation of Western Baja California, Mexico, as Indicated by Marine Terraces and Associated Deposits. Coastal Dune Systems of Northwest Baja California, Mexico. Coastal Salt Marshes of Northwest Baja California, Mexico.  

National Technical Information Service (NTIS)

Contents: Quaternary deformation of Western Baja California, Mexico, as Indicated by Marine Terraces and Associated Deposits; Coastal dune systems of Northwest Baja California, Mexico; Coastal salt marshes of Northwest Baja California, Mexico.

A. R. Orme

1973-01-01

265

Isolation and Characterization of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria Associated with the Rhizosphere of Salt Marsh Plants  

PubMed Central

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, morphologic, and molecular properties. Identification of the isolates based on their fatty acid profiles and partial 16S rRNA gene sequences assigned them to three main bacterial groups: gram-negative pseudomonads; gram-positive, non-spore-forming nocardioforms; and the gram-positive, spore-forming group, Paenibacillus. Genomic digest patterns of all isolates were used to determine unique isolates, and representatives from each bacterial group were chosen for further investigation. Southern hybridization was performed using genes for PAH degradation from Pseudomonas putida NCIB 9816-4, Comamonas testosteroni GZ42, Sphingomonas yanoikuyae B1, and Mycobacterium sp. strain PY01. None of the isolates from the three groups showed homology to the B1 genes, only two nocardioform isolates showed homology to the PY01 genes, and only members of the pseudomonad group showed homology to the NCIB 9816-4 or GZ42 probes. The Paenibacillus isolates showed no homology to any of the tested gene probes, indicating the possibility of novel genes for PAH degradation. Pure culture substrate utilization experiments using several selected isolates from each of the three groups showed that the phenanthrene-enriched isolates are able to utilize a greater number of PAHs than are the naphthalene-enriched isolates. Inoculating two of the gram-positive isolates to a marine sediment slurry spiked with a mixture of PAHs (naphthalene, fluorene, phenanthrene, and pyrene) and biphenyl resulted in rapid transformation of pyrene, in addition to the two- and three-ringed PAHs and biphenyl. This study indicates that the rhizosphere of salt marsh plants contains a diverse population of PAH-degrading bacteria, and the use of plant-associated microorganisms has the potential for bioremediation of contaminated sediments.

Daane, L. L.; Harjono, I.; Zylstra, G. J.; Haggblom, M. M.

2001-01-01

266

Interactive effects of atmospheric CO 2 enrichment, salinity and flooding on growth of C 3 ( Elymus athericus ) and C 4 ( Spartina anglica ) salt marsh species  

Microsoft Academic Search

The growth response of Dutch salt marsh species (C3 and C4) to atmospheric CO2 enrichment was investigated. Tillers of the C3 speciesElymus athericus were grown in combinations of 380 and 720 µ11-1 CO2 and low (O) and high (300 mM NaCl) soil salinity. CO2 enrichment increased dry matter production and leaf area development while both parameters were reduced at high

G. M. Lenssen; J. Lamers; M. Stroetenga; J. Rozema

1993-01-01

267

Geochemistry of salt marsh sediments deposited during simulated sea-level rise and consequences for recent and Holocene coastal development of NW Germany  

NASA Astrophysics Data System (ADS)

De-embankment in the salt marshes of the island of Langeoog was carried out in 2004, thereby inducing an artificial transgression within an area of 2.2 km2. Material from three suspended matter traps (SMTs) located along a N-S transect was collected monthly between January 2006 and February 2007. Besides geochemical (major and trace elements) and grain-size analyses, the duration and height of water cover were continuously measured by pressure gauges during the sampling period at two sites, thus revealing inundation frequency (max. 280 year-1) and level (max. 2.4 m). Generally, the silt-dominated SMT material exhibits a geochemical composition similar to that of suspended particulate matter from the adjacent Wadden Sea. However, distinctly increasing enrichments of TOC, P, Mn and Mo from the shoreline towards the higher salt marsh clearly indicate fractionation processes during material transport. Geochemical comparison with older Holocene coastal deposits reveals a mixture of brackish and tidal flat sediments, thus reflecting an early stage of sea-level rise and the development from a terrestrial towards a marine-dominated system. Sedimentation rates are higher than the local sea-level rise, as revealed by vertical salt marsh growth. Storm surges deliver the highest amounts of sediment and play an important role in salt marsh accumulation within the study area. Average accumulation rates of TOC (780 t year-1), P (54 t year-1) and Mn (5.2 t year-1) in the de-embanked area suggest that the former sand-dominated sediments currently receive significant amounts of reactive organic-rich material, thus fostering biogeochemical cycling.

Kolditz, Kerstin; Dellwig, Olaf; Barkowski, Jan; Badewien, Thomas H.; Freund, Holger; Brumsack, Hans-Jürgen

2012-02-01

268

Habitat-specific nutrient removal and release in Oregon salt marshes  

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

269

Biosphere 2's Marsh Biome  

NASA Technical Reports Server (NTRS)

The Marsh Biome, which was modeled after the mangroves and marshes of southwest Florida, has an area of 441.2 sq m separated into three hydrologically independent sections: the Freshwater, Oligohaline and Salt Marshes. The divisions are made based on their salinity (approximately 0, 4, and 34 ppt. respectively), but they also contain different biological communities. The Freshwater and Oligohaline Marshes are mostly filled with various grasses and several trees, while the Salt Marsh houses regions of red, black, and white mangroves (Rhizophora mangle, Avicennia germinans, and Languncularia racemosa respectively). Overall, there are an estimated 80 species of plants within the biome. Water in the Salt Marsh follows a meandering stream from the algal turf scrubbers (apparatuses that clean the water of its nutrients and heavy metals while increasing dissolved oxygen levels) which have an outlet in the Salt Marsh section near sites 4 and 5 to the Fringing Red Mangrove section. The sections of the Salt Marsh are separated by walls of concrete with openings to allow the stream to flow through. Throughout this study, conducted through the months of June and July, many conditions within the biome remained fairly constant. The temperature was within a degree or two of 25 C, mostly depending on whether the sample site was in direct sunlight or shaded. The pH throughout the Salt Marsh was 8.0 +/- 0.2, and the lower salinity waters only dropped below this soon after rains. The water rdepth and dissolved oxygen varied, however, between sites.

Molnar, Jennifer; Goodridge, Kelven

1997-01-01

270

Assessment of hydraulic restoration of San Pablo Marsh, California.  

PubMed

Inter-tidal marshes are dynamic diverse ecosystems at the transition zone between terrestrial and ocean environments. Geomorphologically, inter-tidal salt marshes are vegetated land-forms at elevations slightly greater than mean tidal levels that have distributed channels formed under ebb (drainage) tidal flows that widen and deepen in the seaward direction. The drainage channels enable tidal flows to circulate sediments and nutrients through the marsh system during normal tidal events, while depositing sediments during storm or seismic events. This dynamic system encourages considerable biodiversity while simultaneously providing water quality enhancement features that service marsh terrestrial life and marine life in the estuary. Reservoir creation limiting sediment transport, anticipated large increases in sea levels as well as agricultural and urban development have resulted in significant loss of inter-tidal marshes and subsequent adverse impacts on waterfowl, infauna and fisheries. The complex and continuously changing marsh channel hydraulics and sedimentary processes have severely constrained quantitative modeling of these marsh systems such that restoration/creation efforts remain something of an empirical science and further assessments are needed. The purpose of this paper is to outline current understanding of salt marsh hydrodynamics, sediment accretion processes and subsequent response of marsh vegetation to set the stage for assessment of a marsh restoration effort along San Pablo Bay near San Francisco, California. Several kilometers of drainage channels were constructed in a 624 ha disturbed salt marsh to restore tidal circulation and vegetation so as to enhance habitat for threatened species (e.g. clapper rail, harvest mouse, delta smelt and potentially anadromous fish species). Two distinct drainage channel systems ('east' and 'west') were installed having similar channel dimensions common to salt marshes in the region, but having design bankfull tidal prism volumes differing by a factor of two. Following channel excavation, main channel tidal flows and sediment loads as well as marsh sediment accretion rates were monitored to assess the relative success of the excavation in restoring tidal circulation and vegetation (Salicornia spp.) to the marsh. Annual aerial surveys corroborated with ground-truthing indicated that marsh vegetation rapidly expanded, from 40 to 85% coverage several years following excavation. The 'east' channel intake was nearly completely silted in within three years. However, channel surveys and flow measurements indicated that the 'east' channel system tidal prism was only about 1200 m3, more than an order of magnitude less than that of the stable 'west' channel system. Marsh sediment accretion rates were on the order of 7-8 mm yr(-1), a rate common to the Pacific coast region that exceeds estimated sea level rise rates of approximately 2 mm yr(-1). East channel network siltation resulted in storm and spring tidal flood ponding such that marsh vegetation coverage decreased to 51% of the marsh area and related habitat expansion decreased. These results are considered in terms of the primary inter-tidal marsh factors affecting possible restoration/creation strategies. PMID:15473530

Grismer, Mark E; Kollar, J; Syder, J

2004-11-01

271

Sulfur transformations in the sediments of a New Hampshire salt marsh  

NASA Technical Reports Server (NTRS)

Summer sulfate reduction and sulfide and iron chemistry were monitored in marsh soils along a gradient from a creekside Spartina alterniflora region to an inland area dominated by S. patens. Sulfate reduction rates measured using S-35 increased from 0.4 in June to as much as 4.5 micro-mole/ml(sup -1)d(sup -1) in July in S. alterniflora soils with most rapid rates occurring in the upper few cm. Rates in S. patens soils were approximately equal to 5-8 fold slower with the most rapid rates occurring generally in soils deeper than 10 cm. The recovery percentage of reduced S-35 sulfur varied with depths at both locations; dissolved and acid-volatile sulfides dominating S. alterniflora regions while chromium-reducible solid phases were abundant in S. patens soils. Dissolved sulfide in S. alterniflora soils increased throughout the summer to approximately equal to 2.8 mM while sulfide in S. patens soils was abundant only in soils deeper than 15 cm. Dissolved sulfide covaried inversely with iron. Diel studies demonstrated that sulfide and iron varied approximately equal to two-fold in response to a semi-diurnal tide. Dissolved sulfide turnover was most rapid during periods of active plant growth.

Hines, Mark E.; Knollmeyer, S. L.; Eldridge, A.; Luken, D.; Tugel, Joyce B.; Lyons, W. Berry

1992-01-01

272

The Amoco CadizOil Spill: Evolution of Petroleum Hydrocarbons in the Ile Grande Salt Marshes (Brittany) after a 13-year Period  

NASA Astrophysics Data System (ADS)

The Ile Grande salt marshes (Brittany coast) were polluted by petroleum hydrocarbons after the Amoco Cadizgrounding in 1978. Thirteen years after the oil spill, sediments were analysed for residual hydrocarbons in order to monitor the aliphatic and aromatic hydrocarbon signatures and to assess both qualitatively and quantitatively the changes in composition of the Amoco Cadizoil. Six stations were selected in the Ile Grande salt marshes and sediments were sampled to a depth of 20 cm. For each sample, the hydrocarbon compositions were determined for alkanes, alkenes, aromatics and biomarkers (terpanes, steranes, diasteranes). Hydrocarbon levels drastically decreased between 1978 and 1991, but to different extents according to the initial degree of contamination. In 1991, hydrocarbon concentrations never exceeded 1·7 g kg -1sediment dry weight, and in most cases were less than 0·1 g kg -1sediment dry weight. Even though petroleum hydrocarbons are still present, natural hydrocarbons were also detected at several stations. Changes in some biomarker distributions were observed 13 years after the oil spill. Nevertheless, most of the biomarkers are very stable in the salt marsh environment and remain unaltered even after a 13-year period.

Mille, G.; Munoz, D.; Jacquot, F.; Rivet, L.; Bertrand, J.-C.

1998-11-01

273

Developing multimetric indices for monitoring ecological restoration progress in salt marshes.  

PubMed

Effective tools for monitoring the status of ecological restoration projects are critical for the management of restoration programs. Such tools must integrate disparate data comprised of multiple variables that describe restoration status, including the condition of environmental stressors, landscape connectivity, ecosystem resilience, and ecological structure and function, while communicating these concepts effectively to a wide range of stakeholders. In this paper we describe the process of constructing multimetric indices (MMIs) for monitoring restoration status for restoration projects currently underway on the eastern coast of Saudi Arabia. During this process, an initial suite of measurements is filtered for response and sensitivity to ecosystem stressors, eliminating measurements that provide little information and reducing future monitoring efforts. The retained measurements are rescaled into comparable domain metrics and assembled into MMIs. The MMIs are presented in terms of established restoration theories, including restoration trajectory and restoration endpoint targets. PMID:22341883

Langman, O C; Hale, J A; Cormack, C D; Risk, M J; Madon, S P

2012-04-01

274

A new non-indigenous Crassostrea species in Southwest Atlantic salt marshes affects mortality of the cordgrass Spartina alterniflora  

NASA Astrophysics Data System (ADS)

Biological invasions in marine and coastal systems may produce new trophic and nontrophic interactions influencing the structure of the invaded community. In the intertidal salt marshes of Samborombón Bay (36°19?20?S, 56°46?26?W; mouth of La Plata River; Argentina), there is a new non-indigenous oyster species, Crassostrea sp., which settles on the dominant smooth cordgrass Spartina alterniflora. Here, we analyzed if the oyster affects S. alterniflora. Sampling showed that density of live plant was similar across intertidal levels, but there were higher density of dead plant stems at low intertidal levels. This pattern coincides with higher density and larger shell size of Crassostrea sp. at the low intertidal where oysters are attached to the basal part of the plant stems. An experiment manipulating oysters attached to S. alterniflora stems and oyster mimics shows that Crassostrea sp. can indeed increase mortality of S. alterniflora. The negative effect of bivalves on plant could be because several oysters settle around the Spartina stem, and by growing during the year, strangle the plants increasing their mortality rate. Together, all these evidences strongly suggest that these non-indigenous oysters can control the lower intertidal level of plant distribution in this system.

Lomovasky, Betina J.; Alvarez, Graciela; Addino, Mariana; Montemayor, Diana I.; Iribarne, Oscar

2014-07-01

275

Sediment chemistry associated with native and non-native emergent macrophytes of a Hudson River marsh ecosystem  

Microsoft Academic Search

In tidal freshwater marshes of the Hudson River, coverage byPhragmites australis andLythrum salicaria has increased greatly over the past twenty years, althoughTypha angustifolia is still the predominant vegetation. Prior to any attempts at marsh restoration via removal of exotic\\/invasive plant species,\\u000a we wanted to describe the current relationship between these plants and sediment nutrient pools. Extant stands (n=3 of each)

Pamela Templer; Stuart Findlay; Cathleen Wigand

1998-01-01

276

Great Salt Lake Microbial Communities: The Foundation of a Terminal Lake Ecosystem  

Microsoft Academic Search

Great Salt Lake (GSL) is a natural hypersaline ecosystem and a terminal lake of substantial size. The dramatic fluctuation in water levels and salinity creates an ecological backdrop selective for organisms with a high degree of adaptability. At the macro level, the biodiversity of the GSL ecosystem is simple, due to the limitations of an extreme saline environment: Birds eat

B. K. Baxter; M. Acord; M. R. Riddle; B. Avery

2006-01-01

277

Marsh nutrient export supplied by groundwater discharge: Evidence from radium measurements  

Microsoft Academic Search

We use 228Ra and 226Ra to determine the mass balance of dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) in the North Inlet salt marsh-estuarine system. While this system has only minor freshwater inputs of nutrients or radium, it is an extremely productive ecosystem. In addition, there are significant exports of these dissolved species to the coastal ocean. Saline

J. M. Krest; W. S. Moore; L. R. Gardner; J. T. Morris

2000-01-01

278

Microbial Community Structure Responses to Long-Term Acid-Mine Drainage Contamination in a Coastal Salt Marsh  

NASA Astrophysics Data System (ADS)

Constructed wetlands for in situ bioremediation of metals and acid mine drainage (AMD) require the activity of sulfate-reducing bacteria (SRB) to sequester dissolved metals into metal-sulfide precipitates (e.g. Webb et al. 1998). Factors such as low pH and high dissolved [Cu] will constrain the growth of SRB (Sani et al. 2001). Unintentional stimulation of the growth of sulfuric acid-generating microbes, such as Thiomicrospira, would also decrease bioremediation efficiency. Few studies of natural wetlands under long-term forcing by AMD and metals have been performed. We characterized the microbial diversity, mineralogy and geochemistry of a contaminated salt marsh at the Richmond Field Station along the East San Francisco Bay. For over 50 years, this marsh has received pH ˜2, metal-rich groundwaters from near-surface pyrite tailings and paint and explosives manufacturers. Sediment cores (30-40 cm long) were taken from contaminated sites with pH ˜2 and ˜8. Whole-sediment analyses showed As, Cd, Cu, Se, Zn, and Pb are present at 100s of ppm (URS Corp. 2001). ICP-AES analyses of pore waters showed 10-50 ppb As. All cores contained fine-grained black muds and exhibited a noticeable sulfide odor. Transmission electron microscope studies of marsh sediments support the sequestration of metals into aggregates of nanocrystalline sulfides. Isotopic analyses of pore-water sulfate taken at several depths within cores of AMD pool (SMR-1) and tidal slough sediments (SM148-1) at pHs 2-3 and 7-8, respectively, all yielded significant negative ? 34S values (-25 to -35 ‰ ) consistent with bacterial sulfate reduction. However, values of the upper 10 cm of SMR-1 are roughly 10 ‰ heavier than seawater and support a significant contribution of dissolved sulfate from direct oxidation of pyrite tailings. 16S gene clone libraries revealed significantly different microbial community structures in cores SMR-1 and SM148-1. Roughly 40% of the library from SMR-1 consisted of Thiomicrospira denitrificans (22%) and several other bacteria capable of oxidizing reduced sulfur species (18%). SRB were present (15%), however, and probably reflect contributions from core depths at which acidity is attenuated by tidal flushing. In contrast, SM148-1 contained ˜25% SRB, and aero- and halo-tolerant SRB were enriched from this core by cultivation. The dominance of Thiomicrospira and other sulfur-/sulfide-oxidizing bacteria, in combination with isotopic results, showed microbially-mediated pyrite oxidation in SMR-1. In contrast, Desulfobacterium spp. dominated the community in SM148-1 and reduced dissolved metals to near or below EPA action levels. References: Webb et al. 1998, J. Appl. Microbio., 84, 240-248; Sani et al. 2001, Applied Env. Microbio., 67, 4765-4772; URS Corp. 2001, Report 51.09967067.00.

Moreau, J. W.; Zierenberg, R. A.; Banfield, J. F.

2004-12-01

279

Exploring the genome of the salt-marsh Spartina maritima (Poaceae, Chloridoideae) through BAC end sequence analysis.  

PubMed

Spartina species play an important ecological role on salt marshes. Spartina maritima is an Old-World species distributed along the European and North-African Atlantic coasts. This hexaploid species (2n = 6x = 60, 2C = 3,700 Mb) hybridized with different Spartina species introduced from the American coasts, which resulted in the formation of new invasive hybrids and allopolyploids. Thus, S. maritima raises evolutionary and ecological interests. However, genomic information is dramatically lacking in this genus. In an effort to develop genomic resources, we analysed 40,641 high-quality bacterial artificial chromosome-end sequences (BESs), representing 26.7 Mb of the S. maritima genome. BESs were searched for sequence homology against known databases. A fraction of 16.91% of the BESs represents known repeats including a majority of long terminal repeat (LTR) retrotransposons (13.67%). Non-LTR retrotransposons represent 0.75%, DNA transposons 0.99%, whereas small RNA, simple repeats and low-complexity sequences account for 1.38% of the analysed BESs. In addition, 4,285 simple sequence repeats were detected. Using the coding sequence database of Sorghum bicolor, 6,809 BESs found homology accounting for 17.1% of all BESs. Comparative genomics with related genera reveals that the microsynteny is better conserved with S. bicolor compared to other sequenced Poaceae, where 37.6% of the paired matching BESs are correctly orientated on the chromosomes. We did not observe large macrosyntenic rearrangements using the mapping strategy employed. However, some regions appeared to have experienced rearrangements when comparing Spartina to Sorghum and to Oryza. This work represents the first overview of S. maritima genome regarding the respective coding and repetitive components. The syntenic relationships with other grass genomes examined here help clarifying evolution in Poaceae, S. maritima being a part of the poorly-known Chloridoideae sub-family. PMID:23877482

Ferreira de Carvalho, J; Chelaifa, H; Boutte, J; Poulain, J; Couloux, A; Wincker, P; Bellec, A; Fourment, J; Bergès, H; Salmon, A; Ainouche, M

2013-12-01

280

Seasonal Patterns of CO2 and Water Vapor Exchange of 'Juncus roemerianus' Scheele in a Georgia Salt Marsh.  

National Technical Information Service (NTIS)

CO2 and water vapor exchange studies of intact plants of black needle rush (Juncus roemerianus) were conducted in an undisturbed marsh community on Sapelo Island, Georgia. The seasonal patterns of the light and temperature responses of net photosynthesis,...

J. R. Giurgevich E. L. Dunn

1978-01-01

281

210Pb and 137Cs as chronometers for salt marsh accretion in the Venice Lagoon - links to flooding frequency and climate change.  

PubMed

Five salt marsh sediment cores from different parts of the Venice Lagoon were studied to determine their depositional history and its relationship with the environmental changes occurred during the past approximately 100 years. X-radiographs of the cores show no disturbance related to particle mixing. Accretion rates were calculated using a constant flux model applied to excess (210)Pb distributions in the cores. The record of (137)Cs fluxes to the sites, determined from (137)Cs profiles and the (210)Pb chronologies, shows inputs from the global fallout of (137)Cs in the late 1950s to early 1960s and the Chernobyl accident in 1986. Average accretion rates in the cores are comparable to the long-term average rate of mean sea level rise in the Venice Lagoon ( approximately 0.25 cm y(-1)) except for a core collected in a marsh presumably affected by inputs from the Dese River. Short-term variations in accretion rate are correlated with the cumulative frequency of flooding, as determined by records of Acqua Alta, in four of the five cores, suggesting that variations in the phenomena causing flooding (such as wind patterns, storm frequency and NAO) are short-term driving forces for variations in marsh accretion rate. PMID:17475372

Bellucci, L G; Frignani, M; Cochran, J K; Albertazzi, S; Zaggia, L; Cecconi, G; Hopkins, H

2007-01-01

282

Impact of crude oil exposure on nitrogen cycling in a previously impacted Juncus roemerianus salt marsh in the northern Gulf of Mexico.  

PubMed

This study investigated potential nitrogen fixation, net nitrification, and denitrification responses to short-term crude oil exposure that simulated oil exposure in Juncus roemerianus salt marsh sediments previously impacted following the Deepwater Horizon accident. Temperature as well as crude oil amount and type affected the nitrogen cycling rates. Total nitrogen fixation rates increased 44 and 194 % at 30 °C in 4,000 mg kg(-1) tar ball and 10,000 mg kg(-1) moderately weathered crude oil treatments, respectively; however, there was no difference from the controls at 10 and 20 °C. Net nitrification rates showed production at 20 °C and consumption at 10 and 30 °C in all oil treatments and controls. Potential denitrification rates were higher than controls in the 10 and 30?ºC treatments but responded differently to the oil type and amount. The highest rates of potential denitrification (12.7?±?1.0 nmol N g(-1) wet h(-1)) were observed in the highly weathered 4,000 mg kg(-1) oil treatment at 30 °C, suggesting increased rates of denitrification during the warmer summer months. These results indicate that the impacts on nitrogen cycling from a recurring oil spill could depend on the time of the year as well as the amount and type of oil contaminating the marsh. The study provides evidence for impact on nitrogen cycling in coastal marshes that are vulnerable to repeated hydrocarbon exposure. PMID:24510533

Horel, Agota; Bernard, Rebecca J; Mortazavi, Behzad

2014-06-01

283

Nekton use of intertidal creek edges in low salinity salt marshes of the Yangtze River estuary along a stream-order gradient  

NASA Astrophysics Data System (ADS)

Non-vegetated creek edges were investigated to explore spatial nekton use patterns in a low salinity intertidal salt marsh creek network of the Yangtze River estuary along a stream-order gradient with four creek orders. Non-vegetated creek edges were arbitrarily defined as the approximately 3 m extending from the creek bank (the marsh-creek interface) into open water. Nekton was sampled using seine nets during daytime high slack water during spring tides for two or three days each in May through July 2008. Twenty-three nekton species (16 fishes and 7 crustaceans) were caught during the study. Fishes were dominated by gobies ( Mugilogobius abei, Periophthalmus magnuspinnatus, Periophthalmus modestus, Synechogobius ommaturus), mullets ( Chelon haematocheilus, Liza affinis) and Chinese sea bass ( Lateolabrax maculatus). Crustaceans were dominated by mud crab ( Helice tientsinensis) and white prawn ( Exopalaemon carinicauda). Rank abundance curves revealed higher evenness of nekton assemblages in lower-order creeks compared to higher-order creeks. Fish abundance tended to increase with increasing creek order. Crustacean abundance was higher in the first-third order creeks than in the fourth-order creek. Dominant nekton species displayed various trends in abundance and length-frequency distributions along the stream-order gradient. The spatial separation of nekton assemblages between the first-third order creeks and the fourth-order creek could be attributed to geomorphological factors (distance to mouth and cross-sectional area). These findings indicate that both lower- and higher-order creek edges play important yet different roles for nekton species and life history stages in salt marshes.

Jin, Binsong; Qin, Haiming; Xu, Wang; Wu, Jihua; Zhong, Junsheng; Lei, Guangchun; Chen, Jiakuan; Fu, Cuizhang

2010-07-01

284

Plant responses to increased inundation and salt exposure: Potential sea-level rise effects on tidal marsh productivity  

EPA Science Inventory

Sea-level rise (SLR) may increase submergence and salinity exposure for tidal marsh plants. We tested the effects of these two potential stressors on seedling survival and growth in a transplant experiment in a macrotidal estuary in the Pacific Northwest. Plants of seven species ...

285

Assessing the potential for fringing oyster reefs to promote salt marsh accretion on the Virginia Eastern Shore  

NASA Astrophysics Data System (ADS)

Wetland area loss is a matter of concern on all coastlines with the increasing erosion rates and predicted higher rates of sea level rise. This is particularly true of marshes on the Virginia Eastern Shore, where erosion is primarily a function of wind-driven waves, which are directly affected by water depth. Previous studies indicate that fringing oyster reefs successfully reduce erosion rates in low energy wetland environments, and in some places, show accretion. This study used existing natural and man-made fringing oyster reefs in Virginia Coast Reserve (VCR) marshes to determine if the reefs diminished wave energy sufficiently to allow for marsh accretion, and if so, whether the reefs eliminated a particular frequency or lowered the energy throughout the whole wave spectra. Aerial photography was used to determine shoreline change at the study and control sites, as well as the rate of change across the 60-year period of available imagery using Digital Shoreline Analysis System in ArcMap 10. GPS surveys were taken every six months to quantify any short-term shoreline change and compare to rates found from aerial imagery analysis. Successful results from this study could bring to light an alternative method for erosion control that is in keeping with the living shoreline conservation effort, which supports incorporation of as much natural material as possible in constructed erosion controls.

Taube, S. R.

2012-12-01

286

How do how internal and external processes affect the behaviors of coupled marsh mudflat systems; infill, stabilize, retreat, or drown?  

NASA Astrophysics Data System (ADS)

Intertidal coastal environments are prone to changes induced by sea level rise, increases in storminess, and anthropogenic disturbances. It is unclear how changes in external drivers may affect the dynamics of low energy coastal environments because their response is non-linear, and characterized by many thresholds and discontinuities. As such, process-based modeling of the ecogeomorphic processes underlying the dynamics of these ecosystems is useful, not only to predict their change through time, but also to generate new hypotheses and research questions. Here, a three-point dynamic model was developed to investigate how internal and external processes affect the behavior of coupled marsh mudflat systems. The model directly incorporates ecogeomorphological feedbacks between wind waves, salt marsh vegetation, allochthonous sediment loading, tidal flat vegetation and sea level rise. The model was applied to examine potential trajectories of salt marshes on the Eastern seaboard of the United States, including those in the Plum Island Ecosystems (PIE), Virginia Coast Reserve (VCR) and Georgia Coastal Ecosystems (GCE) long term ecological research (LTER) sites. While these sites are undergoing similar rates of relative sea level rise (RSLR), they have distinct differences in site specific environmental drivers including tides, wind waves, allochthonous sediment supply and the presence or absence of seagrass. These differences lead to the emergence of altered behaviors in the coupled salt marsh-tidal flat system. For marsh systems without seagrass or significant riverine sediment supply, conditions similar to those at PIE, results indicated that horizontal and vertical marsh evolution respond in opposing ways to wave induced processes. Marsh horizontal retreat is triggered by large mudflats and strong winds, whereas small mudflats and weak winds reduce the sediment supply to the salt marsh, decreasing its capability to keep pace with sea level rise. Marsh expansion and an eventual lateral equilibrium are possible only with large allochthonous sediment supply. Once marshes expanded, marsh retreat can be prevented by a sediment supply smaller than the one that filled the basin. At the GCE, the Altamaha River allows for enhanced allochthonous supply directly to the salt marsh platform, reducing the importance of waves on the tidal flat. As a result, infilling or retreat become the prevalent behaviors. For the VCR, the presence of seagrass decreases near bed shear stresses and sediment flux to the salt marsh platform, however, seagrass also reduces the wave energy acting on the boundary of the marsh reducing boundary erosion. Results indicate that the reduction in wave power allows for seagrass to provide a strong stabilizing affect on the coupled salt marsh tidal flat system, but as external sediment supply increases and light conditions decline the system reverts to that of a bare tidal flat. Across all systems and with current rates of sea level rise, retreat is a more likely marsh loss modality than drowning.

Carr, J. A.; Mariotti, G.; Wiberg, P.; Fagherazzi, S.; McGlathery, K.

2013-12-01

287

Community ecotoxicology: invertebrate emergence from Fire Trol 934 contaminated vernal pool and salt marsh sediments under contrasting photoperiod and temperature regimes.  

PubMed

Fire retardant chemicals are being used increasingly throughout the world to effectively manage wildland fires. The widespread use and high volume of retardant products being applied increase the potential for contamination of temporary wetlands that represent critical habitat for numerous species. This study aimed at assessing the emergence response of invertebrates from fire-retardant-contaminated sediments derived from two temporary wetlands, a vernal pool and a salt marsh, which differ distinctly in their invertebrate resting egg bank structure. Two application rates (1 and 3 Lm(-2)) of the commercially available fire retardant, Fire Trol 934, were used to simulate environmentally realistic contamination scenarios for wetlands situated in Mediterranean grasslands and shrublands, respectively. Two contrasting emergence conditions (winter versus spring flooding conditions) were simulated to take into account the high inter- and intra-annual variability of pond filling in Mediterranean areas. Results showed a decrease in abundance (p<0.001), taxonomic richness (p<0.001) and biodiversity based on Shannon-Weaver diversity indices (p<0.001) in both wetlands and under both emergence conditions with increased retardant application rate. This was due to the loss of chydorids, daphnids, ostracods, and rotifers in the vernal pool, and rotifers, nematodes, protozoa and aquatic fungi in the salt marsh. The observed patterns were similar for many taxa and community metrics at either retardant level irrespective of hatching regime, suggesting that the timing of pond filling was generally not an important influence in community response to Fire Trol. A multivariate approach to characterize community structure suggests that wetlands that undergo periodic drying are resilient to perturbations by chemicals and that community responses to anthropogenic stressors may be well within the range of response to natural disturbances. PMID:16621061

Angeler, David G; Sánchez, Beatriz; García, Gregorio; Moreno, José M

2006-06-15

288

Differential responses of ammonia-oxidizing archaea and bacteria to long-term fertilization in a New England salt marsh  

PubMed Central

Since the discovery of ammonia-oxidizing archaea (AOA), new questions have arisen about population and community dynamics and potential interactions between AOA and ammonia-oxidizing bacteria (AOB). We investigated the effects of long-term fertilization on AOA and AOB in the Great Sippewissett Marsh, Falmouth, MA, USA to address some of these questions. Sediment samples were collected from low and high marsh habitats in July 2009 from replicate plots that received low (LF), high (HF), and extra high (XF) levels of a mixed NPK fertilizer biweekly during the growing season since 1974. Additional untreated plots were included as controls (C). Terminal restriction fragment length polymorphism analysis of the amoA genes revealed distinct shifts in AOB communities related to fertilization treatment, but the response patterns of AOA were less consistent. Four AOB operational taxonomic units (OTUs) predictably and significantly responded to fertilization, but only one AOA OTU showed a significant pattern. Betaproteobacterial amoA gene sequences within the Nitrosospira-like cluster dominated at C and LF sites, while sequences related to Nitrosomonas spp. dominated at HF and XF sites. We identified some clusters of AOA sequences recovered primarily from high fertilization regimes, but other clusters consisted of sequences recovered from all fertilization treatments, suggesting greater physiological diversity. Surprisingly, fertilization appeared to have little impact on abundance of AOA or AOB. In summary, our data reveal striking patterns for AOA and AOB in response to long-term fertilization, and also suggest a missing link between community composition and abundance and nitrogen processing in the marsh.

Peng, Xuefeng; Yando, Erik; Hildebrand, Erica; Dwyer, Courtney; Kearney, Anne; Waciega, Alex; Valiela, Ivan; Bernhard, Anne E.

2013-01-01

289

Effects of Long-Term Acid-Mine Drainage Contamination on Diversity and Activity of Sulfate-Reducing Bacteria in a Natural Salt Marsh.  

NASA Astrophysics Data System (ADS)

Constructed wetlands have been studied as sites or analogs for in situ bioremediation of metal contaminants from acid mine drainage (AMD) or industrial sources (e.g. Webb et al. 1998). Wetlands bioremediation necessarily invokes the ubiquity and robustness of sulfate-reducing bacteria (SRB) to sequester dissolved metals into various poorly soluble metal-sulfides (e.g. PbS, CdS). However, few studies of natural wetlands under long-term ecological forcing by AMD or other contaminant sources are available for context. We are investigating the microbial diversity, mineralogy and geochemistry of a highly contaminated salt marsh along the East Central San Francisco Bay. For nearly a half-century, areas within this marsh have received acidic and/or metal-rich groundwaters from near-surface pyrite tailings (transported there from Iron Mountain Mine, near Redding, CA) and local industrial sources (e.g. paint and explosives manufacturers). Sediment cores (30-40 cm long) were taken from six contaminated sites in the marsh with pH range of ˜2 to ˜8. Previous analyses (URS Corp. 2001) reported As, Cd, Cu, Se, Zn, and Pb present in sediments at extremely high concentrations (100s of ppm), yet our ICP-AES analyses of pore waters showed only As present at concentrations of 10-50 ppb. We infer, from high-resolution transmission electron microscope (HRTEM) studies of biogenic (SRB biofilm) ZnS (Moreau et al. 2003, in review) and marsh sediments, that contaminant metals have been sequestered into aggregates of nanocrystalline metal-sulfides. Continuous-flow isotope ratio mass spectrometer (CF-IRMS) analyses of pore-water sulfate and sedimentary sulfides allow resolution of contributions to dissolved sulfate and sulfide from tailings oxidation and dissimilatory sulfate reduction. Sulfate analyses from subsections of three cores (pH 2-3, 6-7, 7-8, respectively) all yield ? 34S values consistent with bacterial sulfate reduction. We note that all three cores also contain very fine-grained black muds that are distinguishable from coarser pyrite cinders, and exhibit a noticeably strong sulfide odor. Aero- and halo-tolerant SRB were enriched from circumneutral pH cores, and we hypothesize that acido-tolerant SRB may also be present. Analysis of restriction fragment length polymorphism of whole community 16S rDNA extracted from each core shows an expected increase in diversity between acidic and circumneutal sediments, and clone libraries from both contaminated and uncontaminated marsh sediments are being compared to assess the impact of long-term contamination. References: Webb et al. 1998, J. Appl. Microbio., 84, 240-248; Moreau et al. 2003, Amer. Min., in review; URS Corp. 2001, Report 51.09967067.00.

Moreau, J. W.; Banfield, J. F.

2003-12-01

290

Tidal Marshes: The Boundary between Land and Ocean.  

ERIC Educational Resources Information Center

An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain…

Gosselink, James

291

Process thresholds in plant-wave interactions on saltmarsh surfaces: implications for wave dissipation and marsh stability  

NASA Astrophysics Data System (ADS)

Saltmarshes provide a range of important ecosystem services, amongst others protection from waves during storms. Plant-wave interactions are critical in determining wave energy reduction by the marsh surface, as this is achieved through hydraulic friction at the bed, vegetation and/or soil movement, and wave breaking. While these energy dissipating processes are understood in theory, crucial understanding is lacking as to just how effective marshes are when it really matters, under extreme water levels and waves, when the interaction between the marsh canopy and waves may differ from lower energy conditions. Experiments undertaken in one of the world's largest wave flumes, with a transplanted section of natural salt marsh typical of NW European coasts, provide first evidence of wave dissipation under storm surge conditions. The experiments showed how energy reduction is affected by individual dissipating processes, and also identified the wave energy threshold above which salt marsh vegetation ceases to make an effective contribution to wave attenuation. Beyond this wave height threshold, plant-wave interactions altered, and so did energy dissipation. Furthermore, for wave heights exceeding a height threshold, damage resulted to marsh vegetation in the form of plant stem breakage and removal. The marsh substrate itself remained remarkably stable and resistant to surface erosion, however, under even the highest wave energy conditions. These findings now allow, for the first time, the quantitative assessment of flood risk reduction by salt marshes under extreme conditions and thus provide input into the future engineering of such biophysical buffers in the face of global environmental change.

Moeller, Iris; Spencer, Tom; Rupprecht, Franziska; Kudella, Matthias; Paul, Maike; Van Wesenbeeck, Bregje; Wolters, Guido; Jensen, Kai; Bouma, Tjeerd

2014-05-01

292

Nitrous oxide fluxes at Cobb Mill Creek marsh on the eastern shore of Virginia  

NASA Astrophysics Data System (ADS)

Atmospheric nitrous oxide (N2O) concentrations are increasing at a rate unaccounted for with current detection methods and modeled budgets. Fertilizer nitrate (NO3-) additions in coastal watersheds could potentially lead to significant increases in N2O emissions from salt marsh ecosystems when naturally rapid microbial processes are subject to high levels of nitrate in stream and ground water. We employ a tunable diode laser trace gas analyzer (TGA) connected to a portable flow-through chamber to study N2O emissions at Cobb Mill Creek marsh, which drains a small agricultural watershed in Oyster, VA. Spatial variability of fluxes is determined by deploying the chamber at 12 sites across the marsh during exposure at low tide. Temporal variability is captured by deploying the chamber over a range of tidal regimes. Using these fluxes, we determine the spatial variability of N2O emissions (according to NO3- availability and degree of wetting which varies according to elevation), elucidate the factors that drive temporal variation of N2O emissions, and compare N2O fluxes from vegetated and non-vegetated areas of the marsh. Insight into the driving forces behind the pulsed nature of N2O emissions from salt water marshes can be used to improve modeled N2O budgets.

Funk, C. S.; Scanlon, T. M.

2009-12-01

293

South San Francisco Bay tidal marsh vegetation and elevation surveys-Corkscrew Marsh, Bird Island, and Palo Alto Baylands, California, 1983  

USGS Publications Warehouse

Changes in the topography and ecology of the San Francisco Bay Estuary ('Estuary') during the past 200 years have resulted in the loss of nearly 80 percent of the historical salt marsh in the region. Currently, numerous projects are being undertaken by federal, state, and local governments in an attempt to restore wetland habitat and ecosystem function at a number of locations within the Estuary. Much information is needed concerning the historical topographic and ecologic characteristics of the Estuary to facilitate these restoration efforts. This report presents previously unpublished vegetation and elevation data collected in 1983 by the California State Lands Commission at Corkscrew marsh, Bird Island, and Palo Alto Baylands, all located in South San Francisco Bay. These precise and detailed elevation and plant surveys represent a snapshot of South Bay flora before invasion by the Atlantic smooth cordgrass, Spartina alterniflora. Such precise elevation data are rare for relatively undisturbed marshes in the San Francisco Bay; publication of these historical data may facilitate wetland restoration efforts. Marsh-surface and tidal-channel elevations were determined at a total of 962 stations by differential leveling to established tidal benchmark stations at each site and referenced to Mean Lower Low Water (MLLW) relative to the National Tidal Datum Epoch (1960-78). In addition, presence or absence of nine salt marsh species, percentage plant cover, and percentage bare soil were recorded for 1-square meter quadrats at 648 stations where elevations were determined. Collectively, over the three sites, salt marsh vegetation ranged in elevation from 0.98 to 2.94 m above MLLW. S. foliosa and Salicornia virginica were the most frequently observed plant species. Atriplex patula, Deschampsia cespitosa, and Limonium californicum were each recorded at only one of the three sites.

Orlando, James L.; Drexler, Judy Z.; Dedrick, Kent G.

2005-01-01

294

Comparison of Habitat-Specific Nutrient Removal and Release in Pacific NW Salt Marshes at Multiple Spatial Scales - CERF  

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

295

Comparison of Habitat-Specific Nutrient Removal and Release in Pacific NW Salt Marshes at Multiple Spatial Scales  

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

296

Great Salt Lake Microbial Communities: The Foundation of a Terminal Lake Ecosystem  

NASA Astrophysics Data System (ADS)

Great Salt Lake (GSL) is a natural hypersaline ecosystem and a terminal lake of substantial size. The dramatic fluctuation in water levels and salinity creates an ecological backdrop selective for organisms with a high degree of adaptability. At the macro level, the biodiversity of the GSL ecosystem is simple, due to the limitations of an extreme saline environment: Birds eat the two invertebrates of the lake, and the invertebrates eat phytoplankton. However, analysis of the microbial level reveals an enormous diversity of species interacting with one another and the ecosystem as a whole. Our cultivation, biochemical tests, microscopy and DNA sequencing yielded data on dozens of isolates. These data demonstrate novel species, and possibly genera, living in the lake. In addition, we have discovered viruses (bacteriophage) that prey on the microorganisms. Preliminary data on bacteria dwelling in the gut of the brine shrimp, Artemia franciscana, link these prokaryotic organisms to the food chain for the first time. All of these results taken together open the door for the discussion of the significance of the microbial level of terminal lake ecosystem, particularly in light of lake water contamination and bioremediation possibilities.

Baxter, B. K.; Acord, M.; Riddle, M. R.; Avery, B.

2006-12-01

297

The effects of a Cattail invasion on a Great Lakes coastal marsh  

Microsoft Academic Search

Great Lakes coastal marshes have been increasingly invaded by aggressive exotic plant species, such as the cattail Typha x glauca. T. x glauca has replaced much of the native plant community in Cheboygan Marsh, a coastal marsh on Lake Huron. Investigations done in this marsh during Summer 2004 addressed the T. x glauca invasion impacts on several ecosystem attributes. Multiple

K. Jankowski; S. C. Shattuck; N. C. Tuchman

2005-01-01

298

Abstracts from "Coastal Marsh Dieback in the Northern Gulf of Mexico: Extent, Causes, Consequences, and Remedies  

USGS Publications Warehouse

In the spring of 2000, scientists discovered a new and unprecedented loss of salt marsh vegetation in coastal Louisiana and other areas along the northern coast of the Gulf of Mexico. This dieback of salt marsh vegetation, sometimes called the brown marsh phenomenon', primarily involved the rapid browning and dieback of smooth cordgrass (Spanina alterniflora). Coastal Louisiana has already undergone huge, historical losses of coastal marsh due to both human-induced and natural factors, and the current overall rate of wetland loss (25-35 sq mi 65-91 SQ KM each year) stands to threaten Louisiana's coastal ecosystem, infrastructure, and economy. On January 11-12, 2001, individuals from Federal and State agencies, universities, and the private sector met at the conference 'Coastal Marsh Dieback in the Northern Gulf of Mexico: Extent, Causes, Consequences, and Remedies' to discuss and share information shout the marsh dieback. Presentations discussed trends in the progress of dieback during the summer of 2000 and in environmental conditions occurring at field study sites, possible causes including drought and Mississippi low flow' conditions, changes in soil conditions (salinity, the bioavailability of metals, pathogens, etc.), the potential for wetland loss that could occur if above and below normality occurs and is sustained over an extended period, advanced techniques for tracking the dieback via aerial photography and remote sensing, linkages of marsh hydrology to the dieback, and mechanisms of modeling dieback and recovery. In addition, presentations were made regarding development of a web site to facilitate information sharing and progress in preparation for requests for proposals based on an emergency appropriation by the U.S. Congress. All findings tended to support the idea that the dieback constituted a continuing environmental emergency and research and natural resource management efforts should be expended accordingly.

Edited by Stewart, Robert E., Jr.; Proffitt, C. Edward; Charron, Tammy Michelle

2001-01-01

299

If you've got it, flaunt it: Ingested alkaloids affect corematal display behavior in the salt marsh moth, Estigmene acrea  

PubMed Central

Plant-derived pyrrolizidine alkaloids play an important role in the biology of the salt marsh moth, Estigmene acrea (Lepidoptera: Arctiidae). They are phagostimulants for larvae and they stimulate the growth and development of adult male androconial organs called coremata. In this study, we have shown that the pyrrolizidine alkaloid monocrotaline N-oxide (MNO) fed to larvae also affects the courtship behavior of adult males. Males fed a diet containing MNO display their coremata while males fed on the same diet without alkaloid rarely display. This explains why it has been difficult to replicate field observations of the “lekking” behavior of this species in the laboratory where animals are frequently raised on commercially available diets devoid of alkaloids. Corematal inflation was observed in isolated males and in laboratory leks. The effect of larvae feeding on pyrrolizidine alkaloid on the reproductive behavior of adults suggests that this substance may modify the development of the moth's nervous system and contribute to their unusual dual mating strategies. MNO was also shown to be an adequate precursor for the production of the courtship pheromone hydroxydanaidal.

Jordan, Alex T.; Jones, Tappey H.; Conner, William E.

2005-01-01

300

If you've got it, flaunt it: ingested alkaloids affect corematal display behavior in the salt marsh moth, Estigmene acrea.  

PubMed

Plant-derived pyrrolizidine alkaloids play an important role in the biology of the salt marsh moth, Estigmene acrea (Lepidoptera: Arctiidae). They are phagostimulants for larvae and they stimulate the growth and development of adult male androconial organs called coremata. In this study, we have shown that the pyrrolizidine alkaloid monocrotaline N-oxide (MNO) fed to larvae also affects the courtship behavior of adult males. Males fed a diet containing MNO display their coremata while males fed on the same diet without alkaloid rarely display. This explains why it has been difficult to replicate field observations of the "lekking" behavior of this species in the laboratory where animals are frequently raised on commercially available diets devoid of alkaloids. Corematal inflation was observed in isolated males and in laboratory leks. The effect of larvae feeding on pyrrolizidine alkaloid on the reproductive behavior of adults suggests that this substance may modify the development of the moth's nervous system and contribute to their unusual dual mating strategies. MNO was also shown to be an adequate precursor for the production of the courtship pheromone hydroxydanaidal. PMID:16299591

Jordan, Alex T; Jones, Tappey H; Conner, William E

2005-01-01

301

Distribution of PCDD/Fs and dioxin-like PCBs in sediment and plants from a contaminated salt marsh (Tejo estuary, Portugal).  

PubMed

Concentrations and profiles of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were investigated in sediment and plants collected from a salt marsh in the Tejo estuary, Portugal. The highest PCDD/F and dl-PCB concentrations were detected in uncolonized sediments, averaging 325.25?±?57.55 pg g(-1) dry weight (dw) and 8,146.33?±?2,142.14 pg g(-1) dw, respectively. The plants Sarcocornia perennis and Halimione portulacoides growing in PCDD/F and dl-PCB contaminated sediments accumulated contaminants in roots, stems, and leaves. It was observed that PCDD/F and dl-PCB concentrations in roots were significantly lower in comparison with stems and leaves. In general, concentration of ?PCDD/Fs and ?dl-PCBs in H. portulacoides tissues were found to be twofold higher than those in S. perennis, indicating a difference in the accumulation capability of both species. Furthermore, congener profiles changed between sediments and plant tissues, reflecting a selective accumulation of low chlorinated PCDD/Fs and non-ortho dl-PCBs in plants. PMID:24085516

Nunes, Margarida; Vernisseau, Anaïs; Marchand, Philippe; Le Bizec, Bruno; Ramos, Fernando; Pardal, Miguel A

2014-02-01

302

Cadmium contamination of three bivalve species (oysters, cockles and clams) in Nord Médoc salt marshes (Gironde estuary, France): Geochemical survey and metal bioaccumulation kinetics  

NASA Astrophysics Data System (ADS)

A historical Cd pollution of the Lot-Garonne River system (France) bas led to the contamination of sediment and water of the Gironde Estuary. In spite of the decrease of fluvial Cd inputs since the early 90ies, Cd concentrations in the Gironde oysters remain higher than European norms (5 ?g.g^{-1} dry mass) and the “zone D” classification of the estuary prohibits bivalve production and harvesting for human consumption. A geochemical survey in salt marshes used for aquaculture (crustaceans) has been conducted in order to assess the heavy métal contamination level in these systems periodically alimented by the Gironde water, accompanied by caging experiments on three bivalve species of economical interest: oysters (Crassostrea gigas), cockles (Cerastoderma edule) and clams (Ruditapes philippinarum) to study heavy metal accumulation in these organisms. Distribution of heavy metals in this system is controlled by biogeochemical processes and is independent of routine water management. Contamination levels in the studied species indicate the high accumulation of Cd by oysters. On the other hand, Cd concentrations in benthic species, such as cockles and clams, are clearly lower than European safety limits for human consumption.

Baudrimont, M.; Schäfer, J.; Marie, V.; Maury-Brachet, R.; Bossy, C.; Durrieu, G.; Palvadeau, A.; Maneux, E.; Boudou, A.; Blanc, G.

2003-05-01

303

Changes in photosynthetic yield (Fv/Fm) responses of salt-marsh microalgal communities along an osmotic gradient (Mont-Saint-Michel Bay, France)  

NASA Astrophysics Data System (ADS)

The response of salt-marsh microphytobenthic communities to daily changes is characterized by high microalgal growth rates. In comparison, the irregular tidal submersions that prevail in the extreme macrotidal system of "La Baie du Mont-Saint-Michel" (France) could be considered as a large-scale disturbance. The physiological capacities of microphytobenthic communities along a salinity gradient were assessed for rapid response to osmotic stress, salinity tolerance and changes in response to short-time submersion. The photosynthetic system response (Fv/Fm) of microphytobenthic communities sampled at different levels of the saltmarsh along a conductivity gradient was studied during spring-tide and neap-tide periods. All samples demonstrated a dominant adaptation of the microalgal community to coastal seawater salinity, but response heterogeneity ruled out euryhaline adaptation as the global response of microphytobenthic taxa. The higher and lower salinity tolerances at the seaward and uppermost stations, respectively, were probably due to the occurrence of oversalted or undersalted habitats during the neap tide period. Moreover, the seaward communities were characterized by successive stimulation and inhibition of Fv/Fm during the spring tide period. Such a phenomenon could result from the opposing influences of sea submersion, which supplies resources on the one hand and destabilizes the biofilm on the other hand. Despite the singular response of these saltmarsh microphytobenthic communities to a conductivity gradient, the rapid and irregular salinity changes due to seawater submersion cannot be considered as a stressor for the dominant taxa.

Le Rouzic, Bertrand

2012-12-01

304

Repellency of IR3535, KBR3023, para-menthane-3,8-diol, and deet to black salt marsh mosquitoes (Diptera: Culicidae) in the Everglades National Park.  

PubMed

IR3535, KBR3023, para-Menthane-3,8-diol (PMD), and deet were evaluated in controlled studies with human subjects (n = 5) for repellency to black salt marsh mosquitoes (Ochlerotatus taeniorhynchus Wiedemann), in the Everglades National Park, FL. In tests of 6-h duration, with an average mosquito biting pressure on exposed forearm skin of 19.5 (+/- 13.7) bites per minute, the mean percent repellencies (SE) for IR3535, KBR3023, PDM, and deet was 88.6 (3.2), 97.5 (1.7), 89.2 (2.9), and 94.8 (2.5), respectively. Mean complete protection times (SE) for IR3535, KBR3023, PMD), mean deet were 3.0 (1.0), 5.4 (0.6), 3.8 (1.4), and 5.6 (0.5) h, respectively. Untreated (ethanol) controls provided 0% repellency. When mosquito biting rates on the untreated forearm skin of repellent-treated subjects were compared with biting rates on the forearm skin of control subjects, the former were 23%-40% lower early in tests and as much as 22% higher late in tests. These differences cast doubt on the technical merit of test designs comprising evaluation of more than one repellent at a time on the same human subject while underscoring the importance of untreated subjects as negative controls in field repellent bioassays. PMID:12495189

Barnard, Donald R; Bernier, Ulrich R; Posey, Kenneth H; Xue, Rui-De

2002-11-01

305

Transcriptome de novo assembly from next-generation sequencing and comparative analyses in the hexaploid salt marsh species Spartina maritima and Spartina alterniflora (Poaceae)  

PubMed Central

Spartina species have a critical ecological role in salt marshes and represent an excellent system to investigate recurrent polyploid speciation. Using the 454 GS-FLX pyrosequencer, we assembled and annotated the first reference transcriptome (from roots and leaves) for two related hexaploid Spartina species that hybridize in Western Europe, the East American invasive Spartina alterniflora and the Euro-African S. maritima. The de novo read assembly generated 38?478 consensus sequences and 99% found an annotation using Poaceae databases, representing a total of 16?753 non-redundant genes. Spartina expressed sequence tags were mapped onto the Sorghum bicolor genome, where they were distributed among the subtelomeric arms of the 10 S. bicolor chromosomes, with high gene density correlation. Normalization of the complementary DNA library improved the number of annotated genes. Ecologically relevant genes were identified among GO biological function categories in salt and heavy metal stress response, C4 photosynthesis and in lignin and cellulose metabolism. Expression of some of these genes had been found to be altered by hybridization and genome duplication in a previous microarray-based study in Spartina. As these species are hexaploid, up to three duplicated homoeologs may be expected per locus. When analyzing sequence polymorphism at four different loci in S. maritima and S. alterniflora, we found up to four haplotypes per locus, suggesting the presence of two expressed homoeologous sequences with one or two allelic variants each. This reference transcriptome will allow analysis of specific Spartina genes of ecological or evolutionary interest, estimation of homoeologous gene expression variation using RNA-seq and further gene expression evolution analyses in natural populations.

Ferreira de Carvalho, J; Poulain, J; Da Silva, C; Wincker, P; Michon-Coudouel, S; Dheilly, A; Naquin, D; Boutte, J; Salmon, A; Ainouche, M

2013-01-01

306

Larval salinity tolerance of the South American salt-marsh crab, Neohelice (Chasmagnathus) granulata: physiological constraints to estuarine retention, export and reimmigration  

NASA Astrophysics Data System (ADS)

The semiterrestrial crab Neohelice (= Chasmagnathus) granulata (Dana 1851) is a predominant species in brackish salt marshes, mangroves and estuaries. Its larvae are exported towards coastal marine waters. In order to estimate the limits of salinity tolerance constraining larval retention in estuarine habitats, we exposed in laboratory experiments freshly hatched zoeae to six different salinities (5 32‰). At 5‰, the larvae survived for a maximum of 2 weeks, reaching only exceptionally the second zoeal stage, while 38% survived to the megalopa stage at 10‰. Shortest development and negligible mortality occurred at all higher salt concentrations. These observations show that the larvae of N. granulata can tolerate a retention in the mesohaline reaches of estuaries, with a lower limit of ca. 10 15‰. Maximum survival at 25‰ suggests that polyhaline conditions rather than an export to oceanic waters are optimal for successful larval development of this species. In another experiment, we tested the capability of the last zoeal stage (IV) for reimmigration from coastal marine into brackish waters. Stepwise reductions of salinity during this stage allowed for moulting to the megalopa at 4 10‰. Although survival was at these conditions reduced and development delayed, these results suggest that already the zoea-IV stage is able to initiate the reimmigration into estuaries. After further salinity reduction, megalopae survived in this experiment for up to >3 weeks in freshwater, without moulting to juvenile crabs. In a similar experiment starting from the megalopa stage, successful metamorphosis occurred at 4 10‰, and juvenile growth continued in freshwater. Although these juvenile crabs showed significantly enhanced mortality and smaller carapace width compared to a seawater control, our results show that the late larval and early juvenile stages of N. granulata are well adapted for successful recruitment in brackish and even limnetic habitats.

Anger, Klaus; Spivak, Eduardo; Luppi, Tomás; Bas, Claudia; Ismael, Deborah

2008-06-01

307

Coastal Ecosystem-Based Management with Nonlinear Ecological Functions and Values  

Microsoft Academic Search

A common assumption is that ecosystem services respond linearly to changes in habitat size. This assumption leads frequently to an ``all or none'' choice of either preserving coastal habitats or converting them to human use. However, our survey of wave attenuation data from field studies of mangroves, salt marshes, seagrass beds, nearshore coral reefs, and sand dunes reveals that these

Edward B. Barbier; Evamaria W. Koch; Brian R. Silliman; Sally D. Hacker; Eric Wolanski; Jurgenne Primavera; Elise F. Granek; Stephen Polasky; Shankar Aswani; Lori A. Cramer; David M. Stoms; Chris J. Kennedy; David Bael; Carrie V. Kappel; Gerardo M. E. Perillo; Denise J. Reed

2008-01-01

308

AN ARTIFICIAL MICROBIAL ECOSYSTEM FOR DETERMINING EFFECTS AND FATE OF TOXICANTS IN A SALT-MARSH ENVIRONMENT  

EPA Science Inventory

An artificial laboratory environment designed to determine microbial interactions with pollutant chemicals is proposed. The system is designed to obtain maximum reproducibility between replicates by dividing a single tank into separate closed chambers. Radiolabeled toxicants are ...

309

Morphogenetic effects of alkaloidal metabolites on the development of the coremata in the salt marsh moth, Estigmene acrea (Dru.) (Lepidoptera: Arctiidae).  

PubMed

Pyrrolizidine alkaloids (PAs) play a fundamental role in the sexual biology of the salt marsh moth Estigmene acrea. They are precursors for the male courtship pheromone hydroxydanaidal and they stimulate the growth and development of male pheromone-disseminating organs called coremata. Yet larval Estigmene are polyphagous and feed only sporadically on PA-containing plants and those they utilize contain different classes of PAs. The various PAs ingested are hydrolyzed to the common necine metabolite retronecine and re-esterified to insect-specific alkaloids from which the male pheromone hydroxydanaidal is synthesized. Given this complex metabolic pathway, we investigated the role of retronecine and the insect-specific alkaloids that stem from it as morphogens stimulating corematal growth. Retronecine fed to terminal instar larvae in a standard caterpillar diet stimulated corematal growth. It also stimulated corematal growth when it was injected into the hemolymph of larvae. These results indicate that this common PA metabolite, and/or the insect specific alkaloids produced from it, function as corematal morphogens. The parental forms (alkaloids ingested from the plant) are not strictly necessary for corematal growth. Stimulation of the PA receptors on the galea and ingestion process are also not critical to corematal development. Since the insect-specific alkaloids are the direct precursors for the male courtship pheromone, it is argued that their level is the best indicator of the ultimate pheromone titer and would provide the most accurate developmental signal. The effects of alkaloidal metabolites as morphogens in E. acrea are compared to those for the South Asian arctiines Creatonotus gangis and C. transiens in which the developmental role of PAs was first discovered. PMID:18000873

Jordan, Alex T; Jones, Tappey H; Conner, William E

2007-12-01

310

Changes in protein expression in the salt marsh mussel Geukensia demissa: evidence for a shift from anaerobic to aerobic metabolism during prolonged aerial exposure.  

PubMed

During aerial exposure (emersion), most sessile intertidal invertebrates experience cellular stress caused by hypoxia, and the amount and types of hypoxia-induced stress will differ as exposure time increases, likely leading to altered metabolic responses. We examined proteomic responses to increasing emersion times and decreasing recovery (immersion) times in the mussel Geukensia demissa, which occurs in salt marshes along the east coast of North America. Individuals are found above mean tide level, and can be emersed for over 18 h during spring tides. We acclimated mussels to full immersion at 15°C for 4 weeks, and compared changes in gill protein expression between groups of mussels that were continually immersed (control), were emersed for 6 h and immersed during recovery for 18 h (6E/18R), were emersed for 12 h and recovered for 12 h (12E/12R), or were emersed for 18 h with a 6 h recovery (18E/6R). We found clear differences in protein expression patterns among the treatments. Proteins associated with anaerobic fermentation increased in abundance in 6E/18R but not in 12E/12R or 18E/6R. Increases in oxidative stress proteins were most apparent in 12E/12R, and in 18E/6R changes in cytoskeletal protein expression predominated. We conclude that G. demissa alters its strategy for coping with emersion stress over time, relying on anaerobic metabolism for short- to medium-duration exposure, but switching to an air-gaping strategy for long-term exposure, which reduces hypoxia stress but may cause structural damage to gill tissue. PMID:24501137

Fields, Peter A; Eurich, Chris; Gao, William L; Cela, Bekim

2014-05-01

311

Estimation of Bacterial Cell Numbers in Humic Acid-Rich Salt Marsh Sediments with Probes Directed to 16S Ribosomal DNA  

PubMed Central

The feasibility of using probes directed towards ribosomal DNAs (rDNAs) as a quantitative approach to estimating cell numbers was examined and applied to study the structure of a bacterial community in humic acid-rich salt marsh sediments. Hybridizations were performed with membrane-bound nucleic acids by using seven group-specific DNA oligonucleotide probes complementary to 16S rRNA coding regions. These included a general eubacterial probe and probes encompassing most members of the gram-negative, mesophilic sulfate-reducing bacteria (SRB). DNA was extracted from sediment samples, and contaminating materials were removed by a series of steps. Efficiency of DNA extraction was 48% based on the recovery of tritiated plasmid DNA added to samples prior to extraction. Reproducibility of the extraction procedure was demonstrated by hybridizations to replicate samples. Numbers of target cells in samples were estimated by comparing the amount of hybridization to extracted DNA obtained with each probe to that obtained with a standard curve of genomic DNA for reference strains included on the same membrane. In June, numbers of SRB detected with an SRB-specific probe ranged from 6.0 × 107 to 2.5 × 109 (average, 1.1 × 109 ± 5.2 × 108) cells g of sediment?1. In September, numbers of SRB detected ranged from 5.4 × 108 to 7.3 × 109 (average, 2.5 × 109 ± 1.5 × 109) cells g of sediment?1. The capability of using rDNA probes to estimate cell numbers by hybridization to DNA extracted from complex matrices permits initiation of detailed studies on community composition and changes in communities based on cell numbers in formerly intractable environments.

Edgcomb, Virginia P.; McDonald, John H.; Devereux, Richard; Smith, David W.

1999-01-01

312

Studies of sulfur biogeochemistry, microbiology and paleontology in three anoxic environments: The Black Sea, a salt marsh mat, and an Ordovician black shale  

SciTech Connect

The author studied the biogeochemistry, microbial ecology and paleontology of three anoxic environments. In the Black Sea, three studies dealt with the role of particle fluxes in sulfur cycling and microbial ecology. In the water column, iron sulfides form at the oxic-anoxic interface from dissolved sulfide left after chemical oxidation, based on sulfur isotopes; formation in deep water is minimal and iron-limited. Sinking organic aggregates transport iron sulfides to the bottom. Sedimentary sulfides may originate from sulfide fluxes and record intensity of chemical vs. microbial oxidation at the oxic-anoxic interface. Sulfate reduction rates from modelled diagenesis of organic carbon fluxes agree with other measured rates. A box model summarizes sulfur cycling between water column and sediments. An algal sulfur compound, dimethylsulfoniopropionate (DMSP), precursor to dimethylsulfide (DMS), was measured in deep-sea particle fluxes. DMSP levels in particle fluxes vary seasonally and between oceans. Though DMSP is only 0.005% of organic carbon fluxes, its removal to the deep sea by fluxes may lessen sea-air DMS fluxes. A DMSP-DMS cycle for ocean and sediments is proposed. A third study compared bacteria biomass and morphology in particle fluxes and water column, using TEM and epifluorescence microscopy. Some bacteria had intracellular structures indicating autotrophy. Concentrations in particle fluxes were high compared to sediment bacteria populations elsewhere, but bacterial carbon is a tiny fraction of total organic carbon. In contrast, phototrophic bacteria dominated a microbial mat in a salt marsh where sulfate reduction is important. Cyanobacteria, purple and green sulfur bacteria species were strongly depth-zoned, and cell sizes decreased as depth increased. Also investigated was spatiotemporal change in a fossil lingulid brachiopod from a suboxic facies, using gradient analyses of benthic invertebrate and planktonic graptolite assemblages.

Muramoto, J.A.

1992-01-01

313

Ecosystem-groundwater interactions under changing land uses: Linking water, salts, and carbon across central Argentina  

NASA Astrophysics Data System (ADS)

Although most ecosystems display a one-way connection with groundwater based on the regulation of deep water drainage (recharge), this link can become reciprocal when the saturated zone is shallow and plants take up groundwater (discharge). In what context is the reciprocal link most likely? How is it affected by land use changes? Has it consequences on salt and carbon cycling? We examine these questions across a precipitation gradient in the Pampas and Espinal of Argentina focusing on three vegetation change situations (mean annual rainfall): afforestation of humid (900-1300 mm) and subhumid grassland (700-900 mm/yr of rainfall), annual cultivation of subhumid grasslands (700-800 mm/yr), and annual cultivation of semiarid forests (500-700 mm). Humid and subhumid grasslands have shallow (< 5 m deep) groundwater tables that are poorly consumed by grasses but highly used by planted trees, as evidenced by satellite canopy temperatures, soil moisture and water table level records, and sapflow measurements. Groundwater contributions enhance carbon uptake in plantations compared to grasslands as suggested by aboveground biomass measurements and satellite vegetation indexes from sites with and without access to groundwater. Where rainfall is <1100 mm, grassland afforestation switches water fluxes to groundwater from positive (net recharge) to negative (net discharge) causing a salt accumulation process in soils and groundwater that is ultimately limited by the tolerance to salinity of tree species. Cultivation with corn and soybean can lead to groundwater consumption in the driest belt of subhumid grassland. Up to five-fold yield increases in lowlands vs. uplands during the driest years indicate a dramatic impact of groundwater use on carbon uptake and groundwater salinization suggests a recharge-to- discharge switch. In dry forests groundwater is not accessible (> 15 m deep) and recharge under natural conditions is null. The establishment of crops, however, triggers the onset of recharge, as evidenced by vadose zones getting wetter and leached of atmospheric chloride. Cropping may cause water table raises leading to a two-way coupling of ecosystems and groundwater in the future, as it has been documented for similar settings in Australia and the Sahel. In the Pampas land use change interacts with groundwater consumption leading to higher carbon uptake (humid and subhumid grasslands) and salt accumulation (subhumid grasslands). In the Espinal (semiarid forest) land use change currently involves a one-way effect on groundwater recharge that may switch to a reciprocal connection if regional water table raises occur. Neglecting the role of groundwater in flat sedimentary plains can obscure our understanding of carbon and salt cycling and curtail our attempts to sustain soil and water resources under changing land uses.

Jobbagy, E. G.; Nosetto, M. D.; Santoni, C. S.; Jackson, R. B.

2007-05-01

314

METHODS TO DEFINE MARSH EVALUATION AND PERCENT SUBMERGENCE  

EPA Science Inventory

Elevation can determine the percentage submergence from tides and therefore is one of the controlling factors for plant zonation within salt marshes. To make comparisons among plants from various salt marshes throughout Narragansett Bay, Rhode Island, a method was developed to es...

315

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design  

Microsoft Academic Search

BACKGROUND: In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control,

Ilia Rochlin; Tom Iwanejko; Mary E Dempsey; Dominick V Ninivaggi

2009-01-01

316

Surface elevation dynamics in vegetated Spartina marshes versus unvegetated tidal ponds along the mid-Atlantic coast, USA, with implications to waterbirds  

USGS Publications Warehouse

Mid Atlantic coastal salt marshes contain a matrix of vegetation diversified by tidal pools, pannes, and creeks, providing habitats of varying importance to many species of breeding, migrating, and wintering waterbirds. We hypothesized that changes in marsh elevation were not sufficient to keep pace with those of sea level in both vegetated and unvegetated Spartina alterniflora sites at a number of mid lagoon marsh areas along the Atlantic coast. We also predicted that northern areas would suffer less of a deficit than would southern sites. Beginning in August 1998, we installed surface elevation tables at study sites on Cape Cod, Massachusetts, southern New Jersey, and two locations along Virginia's eastern shore. We compared these elevation changes over the 4-4.5 yr record with the long-term (> 50 yr) tidal records for each locale. We also collected data on waterbird use of these sites during all seasons of the year, based on ground surveys and replicated surveys from observation platforms. Three patterns of marsh elevation change were found. At Nauset Marsh, Cape Cod, the Spartina marsh surface tracked the pond surface, both keeping pace with regional sea-level rise rates. In New Jersey, the ponds are becoming deeper while marsh surface elevation remains unchanged from the initial reading. This may result in a submergence of the marsh in the future, assuming sea-level rise continues at current rates. Ponds at both Virginia sites are filling in, while marsh surface elevation rates do not seem to be keeping pace with local sea-level rise. An additional finding at all sites was that subsidence in the vegetated marsh surfaces was less than in unvegetated areas, reflecting the importance of the root mat in stabilizing sediments. The implications to migratory waterbirds are significant. Submergence of much of the lagoonal marsh area in Virginia and New Jersey over the next century could have major negative (i.e., flooding) effects on nesting populations of marsh-dependent seaside sparrows Ammodramus maritimus, saltmarsh sharp-tailed sparrows A. caudacutus, black rails Laterallus jamaicensis, clapper rails Rallus longirostris, Forster's terns Sterna forsteri, common terns Sterna hirundo, and gull-billed terns Sterna nilotica. Although short-term inundation of many lagoonal marshes may benefit some open-water feeding ducks, geese, and swans during winter, the long-term ecosystem effects may be detrimental, as wildlife resources will be lost or displaced. With the reduction in area of emergent marsh, estuarine secondary productivity and biotic diversity will also be reduced.

Erwin, R.M.; Cahoon, D.R.; Prosser, D.J.; Sanders, G.M.; Hensel, P.

2006-01-01

317

Description of Meloidoderita salina sp. n. (Nematoda, Sphaeronematidae) from a micro-tidal salt marsh at Mont-Saint-Michel Bay in France  

PubMed Central

Abstract Meloidoderita salina sp. n. is described and illustrated from the halophytic plant Atriplex portulacoides L. (sea purslane) growing in a micro-tidal salt marsh in the Mont-Saint-Michel Bay in France. This new species is the first member of Meloidoderita Poghossian, 1966 collected from a saline environment, and is characterized by the following features: sedentary mature females having a small swollen body with a clear posterior protuberance; slightly dorsally curved stylet, 19.9 µm long, with posteriorly sloping knobs; neck region irregular in shape and twisted; well developed secretory-excretory (S–E) pore, with markedly sclerotized S-E duct running posteriorly; prominent uterus bordered by a thick hyaline wall and filled with eggs. The adult female transforms into a cystoid. Eggs are deposited in both egg-mass and cystoid. Cystoids of Meloidoderita salina sp. n. display a unique sub-cuticular hexagonal beaded pattern. Male without stylet, pharyngeal region degenerated, S-E duct prominent, deirids small, developed testis 97.5 µm long, spicules 18.4 µm long, cloacal opening ventrally protruded, small phasmids posterior to cloaca opening and situated at 5.9 (3.2–7.7) µm from tail end, and conical tail ending in a rounded terminus marked with one (rarely two) ventrally positioned mucro. Additionally, some young malesof the new species were observed enveloped in the last J2 cuticle. Second-stage juvenile body 470 µm long, with a 16.4 µm long stylet, prominent rounded knobs set off from the shaft, hemizonid anterior and adjacent to S-E pore, small deirids located just above S-E pore level, genital primordium located at 68–77% of body length, phasmids small and located at about 19 µm from tail tip, and tail 38.7 µm long, tapering to finely pointed terminus with a finger-like projection. Phylogenetic analyses based on the nearly full length small subunit ribosomal DNA sequences of Meloidoderita salina sp. n. revealed a close relationship of the new species with Sphaeronema alni Turkina & Chizhov, 1986 and placed these two species sister to the rest of Criconematina.

Ashrafi, Samad; Mugniery, Didier; van Heese, Evelyn YJ; van Aelst, Adriaan C.; Helder, Johannes; Karssen, Gerrit

2012-01-01

318

Biodiversity of halophytic and sabkha ecosystems in Iran  

Microsoft Academic Search

Iran, with a total surface area of 1.6 Mkm2, is a typical country of large sabkhas, littoral and inland salt marshes, and diverse brackish and salty river ecosystems.\\u000a According to our present knowledge and evaluation of new data, a total of 365 species within 151 genera and 44 families of\\u000a Ir anian vascular plants are known to be true halophytes,

Hossein Akhani

319

Evaluation of marsh development processes at Fire Island National Seashore: Recent and historic perspectives  

USGS Publications Warehouse

Purpose and significance of the study: Salt marshes are dynamic environments, increasing in vertical elevation and migrating, often landward, as sea level rises. With sea level rise greater than marsh elevation increase, marshes can be submerged, marsh soils become waterlogged, and plant growth becomes stressed, often resulting in conversion of vegetation-dominated marsh to mudflat or open water habitat. Given that the rate of sea level rise is expected to accelerate over the next century and that some marshes in the northeast are becoming submerged (e.g., Jamaica Bay, NY), it is important to understand the processes that control marsh development. More specifically, the objectives of this project were to quantify vertical marsh elevation change in relation to recent rates of sea-level rise and to investigate factors or processes that are most influential in controlling the development and maintenance of Fire Island salt marshes.

Roman, C.T.; King, D.R.; Cahoon, D.R.; Lynch, J.C.; Appleby, P.G.

2007-01-01

320

Application of Computer-Aided Tomography (CT) Technology to Visually Compare Belowground Components of Salt Marshes in Jamaica Bay and Long Island, New York  

EPA Science Inventory

Using CT imaging, we found that rapidly deteriorating marshes in Jamaica Bay had significantly less belowground mass and abundance of coarse roots and rhizomes at depth (< 10 cm) compared to more stable areas in the Jamaica Bay Estuary. In addition, the rhizome diameters and pea...

321

Natural History of Nova Scotia Topics & Habitats: Tidal Marsh  

NSDL National Science Digital Library

Basic information describing the plants, animals, ecosystem, distribution and physical aspects of marshes available in PDF format. The website provides an introduction to the habitat, while the document provides much greater detail. Information is geared towards marshes in Nova Scotia, Canada, however, it is still applicable elsewhere. Site links to additional case studies and habitats.

322

Tidal marshes as energy sources for commercially important nektonic organisms: stable isotope analysis  

Microsoft Academic Search

Tidal marshes provide nursery habitats for many commercial nektonic species; thus, determining trophic linkages between tidal marshes and aquatic consumers is important for sustain- ing fishery production in estuarine ecosystems. We examined stable isotopes (?13C, ?15N) in 4 com- mercial nekton species (Chelon haematocheilus, Synechogobius ommaturus, Lateolabrax maculatus and Exopalaemon carinicauda) in the tidal marshes of the Yangtze River estuary,

Weimin Quan; Cuizhang Fu; Binsong Jin; Yiqi Luo; Bo Li; Jiakuan Chen; Jihua Wu

2007-01-01

323

Potential N processing by southern Everglades freshwater marshes: Are Everglades marshes passive conduits for nitrogen?  

NASA Astrophysics Data System (ADS)

The degree of hydrological connectivity in wetlands plays a vital role in determining the flux of energy, material, and nutrients across these wet landscapes. During the last century, compartmentalization of hydrologic flows in the Florida Everglades by canals and levees has had a profound impact on the natural timing and supply of freshwater and nutrients across the southern Everglades. Nitrogen (N) is an understudied nutrient in the phosphorus-limited Everglades; it plays an important role in many Everglades processes. To gain a better understanding of the overall N-dynamics in southern Everglades' marshes and the role that canals play in the distribution of N across this landscape, we analyzed ? 15N natural abundance data for the primary ecosystem components (the macrophyte Cladium jamaicense, marl soils, peat soils, and periphyton). Three sample transects were established in the three main basins of the southern Everglades: Shark River Slough, Taylor Slough, and the C-111 basin. Each transect included sample sites near canal inflows, in interior marshes, and at the estuarine ecotone. Natural abundance ? 15N signatures provided insights into processes that may be enriching the 15N content of ecosystem components across the marsh landscape. We also conducted a combined analysis of ? 15N data, tissue N concentrations, and water column N data to provide a broad overview of N cycling in the freshwater marshes of the southern Everglades. The primary trend that emerged from each basin was a significant 15N enrichment of all ecosystem components at near-canal sites, relative to more downstream sample sites. These data suggest that the phosphorus-limited marshes of the southern Everglades are not inactive conduits for N. Rather, these marshes appear to be actively cycling and processing N as it flows from the canal-marsh interface through downstream freshwater marshes. This finding has important implications to downstream coastal estuaries, including Florida Bay, and to nearshore coastal ocean ecosystems, such as coral reefs, where N is the limiting nutrient.

Wozniak, Jeffrey R.; Anderson, William T.; Childers, Daniel L.; Gaiser, Evelyn E.; Madden, Christopher J.; Rudnick, David T.

2012-01-01

324

The role of large rhizome dispersal and low salinity windows in the establishment of common reed, Phragmites australis , in salt marshes: New links to human activities  

Microsoft Academic Search

In spite of its long history,Phragmites australis’ (Cav.) Trin ex Stuedel invasion in tidal marshes defies explanation. Initial establishment in these systems is particularly\\u000a perplexing, because seedlings and rhizome fragments do not perform well in poorly drained saline environments. We tested the\\u000a possibility that dispersal and burial of large rhizomes, periods of low salinity, and localized, well-drained areas facilitate\\u000a initial

David Bart; Jean Marie Hartman

2003-01-01

325

Respiratory responses of the salt marsh animals, Fundulus heteroclitus, Leiostomus xanthurus, and Palaemonetes pugio to environmental hypoxia and hypercapnia and to the organophosphate pesticide, azinphosmethyl  

Microsoft Academic Search

In tidal saltmarshes in South Carolina hypoxic (low O2) and hypercapnic (high CO2) conditions occur frequently. In the summer, water Po2 was measured in the upper marshes and over a 24-h period ranged from 9 to 170 torr and Pco2 ranged from 0.3 to 12 torr. These conditions depend on the stage of the tide and the time of day.

Richard E. Cochran; Louis E. Burnett

1996-01-01

326

Biogeochemistry of Sediment Samples from Broadkill Marsh, Delaware.  

National Technical Information Service (NTIS)

The later Holocene sedimentary succession beginning about 2500 years B.P. in Broadkill Marsh, Sussex County, Delaware consists of tidal-creek clays and silts about 12 feet thick, overlain by 5 feet of interbedded thin peats and silty clay of salt marsh or...

F. M. Swain

1971-01-01

327

Ecosystems  

NSDL National Science Digital Library

This self-contained module on ecosystems includes a range of fun activities that students can perform in the classroom and at home with family members. They impart important concepts such as observation, identification, measurement, and differentiation.

Science, Houghton M.

328

Effects of open marsh water management on selected tidal marsh resources: a review.  

PubMed

Open Marsh Water Management (OMWM) is a method of salt-marsh mosquito control that advocates source reduction and biological control through selective pond creation and ditching in mosquito breeding areas. This method has been used as an alternative to chemical insecticides in coastal wetlands for 30 years. This paper reviews the effects of OMWM on hydrology, topography, vegetation, mosquitoes, invertebrates, fishes, birds, mammals, and water quality. Other source reduction techniques and the economics of OMWM are also discussed. PMID:9046479

Wolfe, R J

1996-12-01

329

Tidally driven groundwater flow and solute exchange in a marsh: Numerical simulations  

Microsoft Academic Search

Tidal fluctuations drive groundwater flow in salt marsh sediments. This flow could cause significant chemical exchange across the sediment-water interface and could affect marsh ecology. Numerical models of a generalized tidal creek and marsh were constructed to calculate flow patterns and solute exchange between the marsh and creek. The governing equation for saturated\\/unsaturated flow was modified to account for tide-related

Alicia Marie Wilson; Leonard Robert Gardner

2006-01-01

330

Coastal zone development: Mitigation, marsh creation, and decision-making  

NASA Astrophysics Data System (ADS)

Marsh creation is currently receiving wide attention in the United States as an important tool for mitigating the impacts of development in coastal wetlands. The perception that there is no net loss in valuable coastal wetlands when development is mitigated by the creation of man-made marshes can have a substantial impact on the permitting and decision-making processes. The effective result may be the trading of natural salt marshes for man-made marshes. Techniques for marsh creation were developed by the US Army Corps of Engineers to enhance and stabilize dredge spoil materials. Most research sponsored by the Corps has been directed at determining whether these goals have been accomplished. A survey of the research indicates that there is insufficient evidence to conclude that man-made marshes function like natural salt marshes or provide the important values of natural marshes. It is necessary, therefore, for decision-makers to understand the limitations of present knowledge about man-made marshes, realistically evaluate the trade-offs involved, and relegate mitigation to its proper role in the permitting process—post facto conditions imposed on developments that clearly meet state qualifications and policies.

Race, Margaret Seluk; Christie, Donna R.

1982-07-01

331

Ecosystems  

NSDL National Science Digital Library

This "Ecosystems" module has four units of instruction. The units include: natural selection, population balance, exchange cycles, and environmental protection. Each module has a "Hazards" link that leads to a menu of study units on various environmental hazards (such as oil spills, farm runoff, insecticides, and so on).

Klemm, W. R.

2002-01-01

332

Distribution and abundance of tidal marshes along the coast of maine  

USGS Publications Warehouse

Planimetry studies of coastal geology maps prepared by the Maine Geological Survey show that there is more than an order of magnitude more tidal marsh area in the state of Maine than documented in previously published estimates. The highly convoluted coast of Maine, which is approximately 5,970 km long, contains almost 79 km2 of salt marsh, far more than any other New England state, New York, or the Bay of Fundy region. Reasonable estimates for the per-unit primary productivity of salt marshes lead to projections of total marsh productivity on the order of 1010 g dry weight yr-1 for the Maine coast and 1011 g dry weight yr-1 for the Gulf of Maine as a whole. Distribution of tidal marsh area is strongly controlled by coastal geomorphology, which varies considerably along the coast of Maine. The salt marsh area is concentrated in the southwestern coastal region of arcuate bays, where marshes have developed behind sandy beaches. A series of long islands and bedrock peninsulas in the south-central portion of the coast also provides sheltered areas where large marshes occur. Northeast of Penobscot Bay salt marshes become more numerous and smaller in average areal extent. A lack of protection from waves, along with limited sources of glacio-fluvial and glacio-marine sediments, restricts the occurrence of salt marshes in that region to the frignes of coves and tidal rivers. ?? 1987 Estuarine Research Federation.

Jacobson, H. A.; Jacobson, G. L.; Kelley, J. T.

1987-01-01

333

14. View of Sterling Creek Marsh east across the marsh, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. View of Sterling Creek Marsh east across the marsh, with canal in foreground - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

334

12. View of Sterling Creek Marsh looking southeast across marsh, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. View of Sterling Creek Marsh looking southeast across marsh, with canal in foreground - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

335

Ecosystems  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on biodiversity within ecosystems and within species. Students visit a local area and collect leaves to demonstrate how diverse life can exist within a small area. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

Herzog, R.

336

Ecosystems  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on biodiversity within ecosystems and within species. Students visit a local area and collect leaves to demonstrate how diverse life can exist within a small area. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

2007-12-12

337

Sedimentation and response to sea-level rise of a restored marsh with reduced tidal exchange: Comparison with a natural tidal marsh  

USGS Publications Warehouse

Along coasts and estuaries, formerly embanked land is increasingly restored into tidal marshes in order to re-establish valuable ecosystem services, such as buffering against flooding. Along the Scheldt estuary (Belgium), tidal marshes are restored on embanked land by allowing a controlled reduced tide (CRT) into a constructed basin, through a culvert in the embankment. In this way tidal water levels are significantly lowered (ca. 3 m) so that a CRT marsh can develop on formerly embanked land with a ca. 3 m lower elevation than the natural tidal marshes. In this study we compared the long-term change in elevation (?E) within a CRT marsh and adjacent natural tidal marsh. Over a period of 4 years, the observed spatio-temporal variations in ?E rate were related to variations in inundation depth, and this relationship was not significantly different for the CRT marsh and natural tidal marsh. A model was developed to simulate the ?E over the next century. (1) Under a scenario without mean high water level (MHWL) rise in the estuary, the model shows that the marsh elevation-?E feedback that is typical for a natural tidal marsh (i.e. rising marsh elevation results in decreasing inundation depth and therefore a decreasing increase in elevation) is absent in the basin of the CRT marsh. This is because tidal exchange of water volumes between the estuary and CRT marsh are independent from the CRT marsh elevation but dependent on the culvert dimensions. Thus the volume of water entering the CRT remains constant regardless of the marsh elevation. Consequently the CRT MHWL follows the increase in CRT surface elevation, resulting after 75 years in a 2–2.5 times larger elevation gain in the CRT marsh, and a faster reduction of spatial elevation differences. (2) Under a scenario of constant MHWL rise (historical rate of 1.5 cm a-1), the equilibrium elevation (relative to MHWL) is 0.13 m lower in the CRT marsh and is reached almost 2 times faster. (3) Under a scenario of accelerated MHWL rise (acceleration of 0.02 cm a-1), the CRT marsh is much less able to keep up with the MHWL rise; after 75 years the CRT elevation is already 0.21 m lower than for the natural marsh. In conclusion, this study demonstrates that although short-term (4 years) ?E rates are similar in a restored CRT marsh and natural tidal marsh, these ecosystems may evolve differently in response to sea-level rise in the longer term (10–100 years).

Vandenbruwaene, W.; Maris, T.; Cahoon, D. R.; Meire, P.; Temmerman, S.

2011-01-01

338

Sedimentation and response to sea-level rise of a restored marsh with reduced tidal exchange: Comparison with a natural tidal marsh  

NASA Astrophysics Data System (ADS)

Along coasts and estuaries, formerly embanked land is increasingly restored into tidal marshes in order to re-establish valuable ecosystem services, such as buffering against flooding. Along the Scheldt estuary (Belgium), tidal marshes are restored on embanked land by allowing a controlled reduced tide (CRT) into a constructed basin, through a culvert in the embankment. In this way tidal water levels are significantly lowered (ca. 3 m) so that a CRT marsh can develop on formerly embanked land with a ca. 3 m lower elevation than the natural tidal marshes. In this study we compared the long-term change in elevation (?E) within a CRT marsh and adjacent natural tidal marsh. Over a period of 4 years, the observed spatio-temporal variations in ?E rate were related to variations in inundation depth, and this relationship was not significantly different for the CRT marsh and natural tidal marsh. A model was developed to simulate the ?E over the next century. (1) Under a scenario without mean high water level (MHWL) rise in the estuary, the model shows that the marsh elevation-?E feedback that is typical for a natural tidal marsh (i.e. rising marsh elevation results in decreasing inundation depth and therefore a decreasing increase in elevation) is absent in the basin of the CRT marsh. This is because tidal exchange of water volumes between the estuary and CRT marsh are independent from the CRT marsh elevation but dependent on the culvert dimensions. Thus the volume of water entering the CRT remains constant regardless of the marsh elevation. Consequently the CRT MHWL follows the increase in CRT surface elevation, resulting after 75 years in a 2-2.5 times larger elevation gain in the CRT marsh, and a faster reduction of spatial elevation differences. (2) Under a scenario of constant MHWL rise (historical rate of 1.5 cm a - 1 ), the equilibrium elevation (relative to MHWL) is 0.13 m lower in the CRT marsh and is reached almost 2 times faster. (3) Under a scenario of accelerated MHWL rise (acceleration of 0.02 cm a - 1 ), the CRT marsh is much less able to keep up with the MHWL rise; after 75 years the CRT elevation is already 0.21 m lower than for the natural marsh. In conclusion, this study demonstrates that although short-term (4 years) ?E rates are similar in a restored CRT marsh and natural tidal marsh, these ecosystems may evolve differently in response to sea-level rise in the longer term (10-100 years).

Vandenbruwaene, W.; Maris, T.; Cox, T. J. S.; Cahoon, D. R.; Meire, P.; Temmerman, S.

2011-07-01

339

Impacts of marsh management on coastal-marsh bird habitats  

USGS Publications Warehouse

The effects of habitat-management practices in coastal marshes have been poorly evaluated. We summarize the extant literature concerning whether these manipulations achieve their goals and the effects of these manipulations on target (i.e., waterfowl and waterfowl food plants) and non-target organisms (particularly coastal-marsh endemics). Although we focus on the effects of marsh management on birds, we also summarize the scant literature concerning the impacts of marsh manipulations on wildlife such as small mammals and invertebrates. We address three common forms of anthropogenic marsh disturbance: prescribed fire, structural marsh management, and open-marsh water management. We also address marsh perturbations by native and introduced vertebrates.

Mitchell, L. R.; Gabrey, S.; Marra, P. P.; Erwin, R. M.

2006-01-01

340

Conservation of tidal marshes  

SciTech Connect

This book is the first attempt to examine collectively the various uses and the consequences of marsh conservation efforts. Author Franklin Daiber emphasizes tidal marsh conservation from a holistic perspective rather than from the perspective of a single purpose or special economic interest. He addresses a topic receiving increasing attention, namely the concept of open marsh management as a means of controlling mosquito production without harmful effects on other marsh organisms. Topics considered include: water management; dikes, impoundments, ponds and ditches; reclaimed land and impoundments; ditching and ponding for mosquito control; sewage disposal and waste treatment; dredge material for wetland restoration; insecticides; oil pollution; and petroleum hydrocarbon interactions.

Daiber, F.C.

1986-01-01

341

Carbon and Nitrogen Stocks in the Salt Lake Valley Urban Ecosystem  

Microsoft Academic Search

Water availability exerts a fundamental control over primary production processes in both managed and unmanaged arid land ecosystems. Societal interest in converting grasslands to urban forest has likely increased primary productivity in many western US cities. The changes in primary productivity have the potential to alter C and N stocks of urban soils. Here, we report on trends in soil

J. C. Williamson; P. E. Dennison; J. R. Ehleringer

2008-01-01

342

PERCHLORATE UPTAKE BY SALT CEDAR (TAMARIX RAMOSISSIMA) IN THE LAS VEGAS WASH RIPARIAN ECOSYSTEM  

EPA Science Inventory

Perchlorate ion (CIO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las vegas Wash. Perchlorate is an oxidenat, but its reduction is kineticaly hindered. CXoncern over thyrpoid effects caused the Environmental Protection Agency (EPA...

343

Freshwater Marsh. Habitat Pac.  

ERIC Educational Resources Information Center

The materials in this educational packet are designed for use with students in grades 4 through 7. They consist of an overview, three lesson plans and student data sheets, and a poster. The overview describes how the freshwater marsh is an important natural resource for plant, animal, and human populations and how the destruction of marshes causes…

Fish and Wildlife Service (Dept. of Interior), Washington, DC.

344

Detection of Salt Marsh Vegetation Stress and Recovery after the Deepwater Horizon Oil Spill in Barataria Bay, Gulf of Mexico Using AVIRIS Data  

PubMed Central

The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill.

Khanna, Shruti; Santos, Maria J.; Ustin, Susan L.; Koltunov, Alexander; Kokaly, Raymond F.; Roberts, Dar A.

2013-01-01

345

Detection of salt marsh vegetation stress and recovery after the Deepwater Horizon Oil Spill in Barataria Bay, Gulf of Mexico using AVIRIS data.  

PubMed

The British Petroleum Deepwater Horizon Oil Spill in the Gulf of Mexico was the biggest oil spill in US history. To assess the impact of the oil spill on the saltmarsh plant community, we examined Advanced Visible Infrared Imaging Spectrometer (AVIRIS) data flown over Barataria Bay, Louisiana in September 2010 and August 2011. Oil contamination was mapped using oil absorption features in pixel spectra and used to examine impact of oil along the oiled shorelines. Results showed that vegetation stress was restricted to the tidal zone extending 14 m inland from the shoreline in September 2010. Four indexes of plant stress and three indexes of canopy water content all consistently showed that stress was highest in pixels next to the shoreline and decreased with increasing distance from the shoreline. Index values along the oiled shoreline were significantly lower than those along the oil-free shoreline. Regression of index values with respect to distance from oil showed that in 2011, index values were no longer correlated with proximity to oil suggesting that the marsh was on its way to recovery. Change detection between the two dates showed that areas denuded of vegetation after the oil impact experienced varying degrees of re-vegetation in the following year. This recovery was poorest in the first three pixels adjacent to the shoreline. This study illustrates the usefulness of high spatial resolution airborne imaging spectroscopy to map actual locations where oil from the spill reached the shore and then to assess its impacts on the plant community. We demonstrate that post-oiling trends in terms of plant health and mortality could be detected and monitored, including recovery of these saltmarsh meadows one year after the oil spill. PMID:24223872

Khanna, Shruti; Santos, Maria J; Ustin, Susan L; Koltunov, Alexander; Kokaly, Raymond F; Roberts, Dar A

2013-01-01

346

Living with salt: metabolic and phylogenetic diversity of archaea inhabiting saline ecosystems.  

PubMed

Archaea that live at high salt concentrations are a phylogenetically diverse group of microorganisms. They include the heterotrophic haloarchaea (class Halobacteria) and some methanogenic Archaea, and they inhabit both oxic and anoxic environments. In spite of their common hypersaline environment, halophilic archaea are surprisingly diverse in their nutritional demands, range of carbon sources degraded (including hydrocarbons and aromatic compounds) and metabolic pathways. The recent discovery of a new group of extremely halophilic Euryarchaeota, the yet uncultured Nanohaloarchaea, shows that the archaeal diversity and metabolic variability in hypersaline environments is higher than hitherto estimated. PMID:22339687

Andrei, Adrian-?tefan; Banciu, Horia Leonard; Oren, Aharon

2012-05-01

347

Improving fossil fuel emissions scenarios with urban ecosystem studies: A case study in the Salt Lake-Ogden metropolitan region  

NASA Astrophysics Data System (ADS)

Scenarios of the future trajectory of fossil fuel emissions have been generated at the global scale using assumptions about regional to global economic growth and demography. A limitation to this approach is the mismatch in scale between local geographical, cultural, and economic factors that influence patterns of energy and fuel use and their impact on global emissions. However, resolving mismatches between local and global processes has been successfully addressed in other aspects of carbon cycle science, such as natural sources and sinks of carbon in terrestrial ecosystems. We propose a similar approach for reducing uncertainty in fossil fuel emissions scenarios with process-level studies of the factors underlying emissions at the local scale. We initiated a project to apply a whole ecosystem framework to the study of CO2 emissions in a rapidly urbanizing region in the United States. Our goal was to quantify both biophysical and socioeconomic aspects of urban ecosystem function that determined net CO2 emissions from the major sectors in the Salt Lake-Ogden metropolitan region, an area characterized by good historical records, a highly seasonal climate, and a rapid rate of both population growth and urban expansion. We analyzed the strong linkages between energy use and climate in the region with data from the local utilities. We also applied a linked land use- transportation framework that quantified interactions between urban development and emissions from the transportation sector. These processes were captured in a systems dynamics model of urban ecosystem function that incorporated stakeholder involvement in model development using a mediated modeling approach. The model was validated with direct measurements of CO2 fluxes by eddy covariance and attribution of local CO2 concentrations to fuel types using stable isotopes. The model may be used to evaluate possible consequences of policy levers such as changes in urban developmental densities, acceleration of urban forestry programs, and implementation of technological developments such as alternative fuels and vehicle fuel efficiency. Combined with comparative studies of other metropolitan areas nationally and internationally, this approach may be used to tune fossil fuel emissions scenarios to the critical local factors that influence emissions in a given region.

Pataki, D. E.; Dudley-Murphy, E. A.; Emmi, P. C.; Forster, C. B.; Mills, J. I.; Pardyjak, E. R.; Peterson, T. R.

2006-12-01

348

Improving fossil fuel emissions scenarios with urban ecosystem studies: A case study in the Salt Lake-Ogden metropolitan region  

NASA Astrophysics Data System (ADS)

Scenarios of the future trajectory of fossil fuel emissions have been generated at the global scale using assumptions about regional to global economic growth and demography. A limitation to this approach is the mismatch in scale between local geographical, cultural, and economic factors that influence patterns of energy and fuel use and their impact on global emissions. However, resolving mismatches between local and global processes has been successfully addressed in other aspects of carbon cycle science, such as natural sources and sinks of carbon in terrestrial ecosystems. We propose a similar approach for reducing uncertainty in fossil fuel emissions scenarios with process-level studies of the factors underlying emissions at the local scale. We initiated a project to apply a whole ecosystem framework to the study of CO2 emissions in a rapidly urbanizing region in the United States. Our goal was to quantify both biophysical and socioeconomic aspects of urban ecosystem function that determined net CO2 emissions from the major sectors in the Salt Lake-Ogden metropolitan region, an area characterized by good historical records, a highly seasonal climate, and a rapid rate of both population growth and urban expansion. We analyzed the strong linkages between energy use and climate in the region with data from the local utilities. We also applied a linked land use- transportation framework that quantified interactions between urban development and emissions from the transportation sector. These processes were captured in a systems dynamics model of urban ecosystem function that incorporated stakeholder involvement in model development using a mediated modeling approach. The model was validated with direct measurements of CO2 fluxes by eddy covariance and attribution of local CO2 concentrations to fuel types using stable isotopes. The model may be used to evaluate possible consequences of policy levers such as changes in urban developmental densities, acceleration of urban forestry programs, and implementation of technological developments such as alternative fuels and vehicle fuel efficiency. Combined with comparative studies of other metropolitan areas nationally and internationally, this approach may be used to tune fossil fuel emissions scenarios to the critical local factors that influence emissions in a given region.

Pataki, D. E.; Dudley-Murphy, E. A.; Emmi, P. C.; Forster, C. B.; Mills, J. I.; Pardyjak, E. R.; Peterson, T. R.

2005-05-01

349

Seasonal flooding, soil salinity and primary production in northern prairie marshes  

Microsoft Academic Search

Hydrologic regime is an important control of primary production in wetland ecosystems. I investigated the coupling of flooding, soil salinity and plant production in northern prairie marshes that experience shallow spring flooding. Field experiments compared whitetop (Scolochloa festucacea) marsh that was: (1) nonflooded, (2) flooded during spring with 25 cm water and (3) nonflooded but irrigated with 1 cm water

Christopher Neill

1993-01-01

350

Nutrient cycling and ecosystem behaviour in a salt-water lake  

NASA Astrophysics Data System (ADS)

A nutrient balance model is developed to describe and evaluate the relations between carbon cycling and nutrient dynamics in saline Lake Grevelingen, a former estuary in the SW-part of the Netherlands. Calculations indicate nutrient limitation of planktonic and benthic microalgae by reversible storage of more than 75% of available silicon and nitrogen in bottom detritus. Mobilization from the bottom is the main nutrient source during summer. Uptake by benthic micro-algae strongly reduces the nutrient flux from shallow bottoms at that time. Uptake of nutrients from the overlaying water by benthic micro-algae during spring can explain the observed decrease of the dissolved silicon concentration in the absence of planktonic diatoms. The conclusion is drawn that planktonic primary production depends on the balance between storage of nutrients in bottom detritus, mineralization, and uptake by benthic micro-algae. Denitrification is considered to be a key process in the nitrogen balance, compensating the nitrogen load, and thus crucial in consolidating the mesotrophic properties of the lake. Factors probably influencing denitrification and hence controlling or promoting eutrophication in shallow marine ecosystems, like the oxygen concentration in the sediment and the suspension feeding bottom fauna community, are discussed. The observed gradual concentration decrease of silicon at an increasing nitrogen concentration, combined with a shift in phytoplankton from diatoms to flagellates, is explained by irreversible fixation of a small fraction of silicon in diatom tests, combined with a high re-solution rate of the labile silicon fraction in detritus.

de Vries, I.; Hopstaken, C. F.

351

Comparison of benthic invertebrate assemblages at Spartina alterniflora marshes reestablished after an oil spill and existing marshes in the Arthur Kill (NY/NJ).  

PubMed

In January 1990, an oil spill damaged salt marshes along the banks of the Arthur Kill (New York and New Jersey, USA). In the years following the spill, Spartina alterniflora seedlings were planted at a number of the oil damaged sites and successfully reestablished at these sites. In 1996, the National Marine Fisheries Service began a study to compare the benthic invertebrate assemblages at the reestablished S. alterniflora marshes to those at nearby existing marshes in the Arthur Kill. Oligochaetes, nematodes, and the small tube-building polychaete, Manayunkia aestuarina were the dominant taxa in the study. Significant differences were found in the abundances of all invertebrate individuals, oligochaetes, and nematodes between the September and May sampling times but not between reestablished and existing marshes. Although benthic invertebrate community structure was similar at reestablished and existing marshes three to four years after planting, the functional similarity of these marshes was not assessed in this study. PMID:12474971

Vitaliano, Joseph J; Reid, Robert N; Frame, Ann B; Packer, David B; Arlen, Linda; Sacco, John N

2002-10-01

352

The temperature sensitivity of organic matter decay in tidal marshes  

NASA Astrophysics Data System (ADS)

Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where ecosystems accumulate organic matter to build soil elevation and survive sea level rise. The long-term viability of marshes, and their carbon pools, depends in part on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of soil organic matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3 year period. We find a moderate increase in decay rate at warmer temperatures (3-6% °C-1, Q10 = 1.3-1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and enhance their ability to survive sea level rise.

Kirwan, M. L.; Guntenspergen, G. R.; Langley, J. A.

2014-04-01

353

Biodiversity of Saline and Brakish Marshes of the Indian River Lagoon: Historic and Current Patterns  

NASA Technical Reports Server (NTRS)

The Indian River Lagoon (IRL) crosses a zone of climatic transition. Historically, marshes dominated saline and brackish environments in the north of the lagoon, while mangroves became important to the south. Distribution of marsh communities was influenced by hydrology, salinity, soil characteristics, and fire, as well as periodic freezes. Marshes of the IRL have been greatly modified since the 1940s. Despite significant modifications, marsh plant species have not been lost from the region, but community and landscape patterns have been greatly modified and ecosystem processes altered.

Schmalzer, Paul A.

1995-01-01

354

Contribution of Cultural Eutrophication to Marsh Loss in Jamaica Bay (NY)  

EPA Science Inventory

Loss of salt marsh area in the Jamaica Bay Estuary (NY) has accelerated in recent years, with loss rates as high as 45 acres per year. A contributing factor to this acceleration is likely cultural eutrophication due to over 6 decades of sewage effluent inputs. We examined marsh...

355

Restoring complex vegetation in urban settings: The case of tidal freshwater marshes  

Microsoft Academic Search

Tidal freshwater marshes have diverse plant communities that vary spatially and temporally due to hydrology, animal activity, and other factors. Development of urban centers along rivers of the U.S. Atlantic coast has reduced the historic extent and quality of these and other coastal wetlands. Because the vegetation of these wetlands is more complex than that of salt and brackish marshes

Andrew H. Baldwin

2004-01-01

356

Guide to Common Tidal Marsh Invertebrates of the Northeastern Gulf of Mexico.  

ERIC Educational Resources Information Center

The major groups of marine and estuarine macroinvertebrates of the tidal marshes of the northern Gulf of Mexico are described in this guide for students, taxonomists and generalists. Information on the recognition characteristics, distribution, habitat, and biology of salt marsh species from the coelenterate, annelid, mollusk and arthropod phyla…

Heard, Richard W.

357

Coastal marsh degradation: modeling the influence of vegetation die-off patterns on flow and sedimentation  

NASA Astrophysics Data System (ADS)

Coastal marshes are vulnerable ecosystems that provide ecosystem functions such as storm protection and carbon sequestration. However, degradation of vegetated marshes into bare tidal flats or open water has been reported as a worldwide phenomenon, threatening their valuable wetland functions. Moreover, tidal marshes and bare flats are considered as alternative stable ecosystem states, which implies that, once vegetated marshes have degraded to bare flats, the (re)conversion from bare flats to marsh vegetation may be very difficult. Recent aerial photo analysis has demonstrated that the degradation or die-off of a marsh area is a spatial process, whereby vegetation is typically replaced by non-vegetated areas in the form of interior marsh pools, also known as ponds or marsh basins. On a small scale, these pools have similar characteristics among different marshes worldwide: pools that are located further away from tidal channels and with broad channel connections to the tidal channel system appear to have low surface elevations and a low probability for marsh recovery (this is re-establishment of vegetation on the surface). Interior pools located closer to, but that are not connected to channels on the other hand, are positioned on higher elevations and are more likely to recover. These findings may have important implications for the restoration potential of degraded marshes and their functions. We hypothesize that bio-geomorphologic interactions are the main mechanisms causing these differences in elevation and recovery potential of interior marsh pools: pools that are not connected to the channel system, are separated from the channel by vegetation, which reduces the flow velocity, increases sedimentation and may explain our observation of higher surface elevation of this type of pools. In contrast, pools that are connected with the channel system are not protected by vegetation and will experience higher flow velocities and lower sedimentation rates or even erosion, which may explain their lower surface elevation. Therefore the establishment of marsh plants will be unfavorable. So far, however, this hypothesis has not been verified. In order to investigate the influence of these different types of pool patterns on spatial flow and sedimentation patterns, we used an existing hydrodynamic and sediment transport model (Delft3D) that has been calibrated and validated against field data on tidal marsh flow and sedimentation. The model reproduces the bio-geomorphologic effects of complete vegetation removal, but different pool patterns have not been studied until now. By simulating different pool patterns, we are able to verify our hypothesis regarding elevation changes and marsh recovery potential in degraded marsh pools. This highlights the importance of bio-geomorphologic feedbacks for marsh degradation and recovery.

Schepers, Lennert; Wang, Chen; Kirwan, Matthew; Belluco, Enrica; D'Alpaos, Andrea; Temmerman, Stijn

2014-05-01

358

A space-for-time substitution reveals the long-term decline in genotypic diversity of a widespread salt marsh plant, Spartina alterniflora, over a span of 1500 years  

USGS Publications Warehouse

1. Clonal populations face a trade-off between sexual recruitment and vegetative growth and, once established, may undergo continuous declines in genotypic diversity if their sexual recruits make poor competitors. The geological history of delta formation in the Lower Mississippi River Valley was used to age eight 5. alterniflora marshes for use in a space-for-time substitution ranging over 1500 years, in order to determine the long-term effects of clonal growth on genotypic diversity in natural populations. 2. We also predicted that highly heterozygous clones are competitively superior, leading to an increase in the overall level of genetic diversity as a marsh ages and/or to an increasingly positive relationship between clone size and individual heterozygosity, and that the clumping of ramets within clones will occur over increasingly large distances as populations age, while the clumping of genetically related clones will become less pronounced as intraclonal competition begins to obscure the initial effects of localized seedling recruitment. 3. Using molecular markers to differentiate clones, we documented a decline in clonal richness at the rate of approximately 1% 100 years -1 that was accompanied for the first 300-500 years by an increase in the distance over which clumping of ramets within genets occurred. Older populations, in the 500-1500-year range, showed evidence of clone fragmentation. 4. The spatial clustering of kin was observed for only two marshes, and exhibited no clear relationship with marsh age. 5. Whereas the overall level of genetic diversity was consistent among marshes and showed no clear relationship with marsh age, the relationship between heterozygosity and individual clone size became increasingly pronounced within older marshes. 6. Our results suggest that under natural conditions S. alterniflora marshes will rarely reach ages sufficient for the loss of all clonal diversity, or for the effects of inbreeding and drift to pose a significant threat to population viability. ?? 2005 British Ecological Society.

Travis, S. E.; Hester, M. W.

2005-01-01

359

Sensitivity analysis of the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER)  

NASA Astrophysics Data System (ADS)

The San Francisco Estuary contains the largest extent of tidal marsh in the western United States. It is home to several state and federally listed species that are threatened or endangered. Climate change is a potential threat to these tidal marsh habitats through accelerated sea-level rise. The Wetland Accretion Rate Model for Ecosystem Resilience, or WARMER, is a 1-D vertical model of elevation at a point representative of target wetland habitat. WARMER incorporates both biological and physical components of vertical marsh accretion processes based on previous wetland models and is modified to incorporate mechanistic organic matter and inorganic deposition and the predicted SLR curve for San Francisco Estuary. Processes that are currently being modified include relative sea-level rise, inorganic sediment deposition, organic matter production, decomposition, and compaction. The model will be applied to marshes across the San Francisco Estuary and results will be used to evaluate the extent sea-level rise will reduce the functional habitat of the threatened black rail (Laterallus jamaicensis coturniculus), the endangered California clapper rail (Rallus longirostris obsoletus), and the endangered salt marsh harvest mouse (Reithrodontomys raviventris). Here we present a sensitivity analysis of key model parameters. Previous studies have noted that inorganic sediment deposition, initial elevation and pore space are the most sensitive parameters. Consistent with these studies, sensitivity analysis shows that pore space is the most sensitive parameter in the current model and the modified inorganic sediment deposition subroutine is particularly sensitive to the parameterization of settling velocity. Perturbations to initial elevation, the rate of sea level rise, organic matter input rates and percent refractory organic matter had small impacts on the modeled final elevation. Proper characterization of marsh sediment pore space and temporally variable sediment concentrations and floc settling velocities appear important in producing realistic projections of marsh elevation and habitat sustainability.

Swanson, K.; Drexler, J. Z.; Schoellhamer, D. H.; Thorne, K.; Spragens, K.; Takekawa, J.

2010-12-01

360

Bird Predation on Concealed Insects in a Reed-dominated Estuarine Tidal Marsh  

Microsoft Academic Search

Insectivorous birds can provide important ecosystem services, including regulating insect populations. The function of insectivorous\\u000a birds in wetland ecosystems, such as tidal marshes, however, remains largely unexplored. Most studies of top-down interactions\\u000a between insectivorous birds and herbivorous insects focus on insects in exposed-feeding guilds, but rarely on those in concealed-feeding\\u000a guilds. In a reed-dominated estuarine tidal marsh, we examined the

Li-Hu Xiong; Xiang Wu; Jian-Jian Lu

2010-01-01

361

Contributions of mineral and organic components to tidal freshwater marsh accretion  

NASA Astrophysics Data System (ADS)

Vertical accretion in tidal marshes is necessary to prevent submergence due to rising sea levels. Mineral materials may be more important in driving vertical accretion in tidal freshwater marshes, which are found near the heads of estuaries, than has been reported for salt marshes. Accretion rates for tidal freshwater marshes in North America and Europe ( n = 76 data points) were compiled from the literature. Simple and multiple linear regression analyses revealed that both organic and mineral accumulations played a role in driving tidal freshwater marsh vertical accretion rates, although a unit mass of organic material contributed ˜4 times more to marsh volume than the same mass input of mineral material. Despite the higher mineral content of tidal freshwater marsh soils, this ability of organic matter to effectively hold water and air in interstitial spaces suggests that organic matter is responsible for 62% of marsh accretion, with the remaining 38% from mineral contributions. The organic material that helps to build marsh elevation is likely a combination of in situ production and organic materials that are deposited in association with mineral sediment particles. Regional differences between tidal freshwater marshes in the importance of organic vs. mineral contributions may reflect differences in sediment availability, climate, tidal range, rates of sea level rise, and local-scale factors such as site elevation and distance to tidal creeks. Differences in the importance of organic and mineral accumulations between tidal freshwater and salt marshes are likely due to a combination of factors, including sediment availability (e.g., proximity to upland sources and estuarine turbidity maxima) and the lability of freshwater vs. salt marsh plant production.

Neubauer, Scott C.

2008-06-01

362

Wetland Weeds: West Indian Marsh Grass (Hymenachne amplexicaulis)1  

Microsoft Academic Search

Wetlands (including swamps, bogs, marshes, mires and lagoons) are important ecosystems that are found on every continent except Antarctica. Wetlands are recognized as valuable sources, sinks, and transformers of a multitude of chemical, biological, and genetic materials (Mitsch and Gosselink 1993), and play an increasingly important role in todays world due to urban and agricultural pollution, and modification of natural

Rodrigo Diaz; William A. Overholt; James P. Cuda

363

Marsh vertical accretion in a Southern California Estuary, U.S.A  

USGS Publications Warehouse

Vertical accretion was measured between October 1992 and March 1994 in low and high saltmarsh zones in the north arm of Tijuana estuary from feldspar market horizons and soil corings. Accretion in the Spartina foliosa low marsh (2-8.5 cm) was related almost entirely to episodic storm-induced river flows between January and March 1993, with daily tidal flooding contributing little or no sediment during the subsequent 12 month period of no river flow. Accretion in the Salicornia subterminalis high marsh was low (~1-2 mm) throughout the 17-month measuring period. High water levels in the salt marsh associated with the storm flows were enhanced in early January 1993 by the monthly extreme high sea level, when the low and high marshes were flooded about 0.5 m above normal high tide levels. Storm flows in January-March 1993 mobilized about 5 million tons of sediment, of which the low salt marsh trapped an estimated 31,941 tonnes, including 971 tonnes of carbon and 77 tonnes of nitrogen. Sediment trapping by the salt marsh during episodic winter floods plays an important role in the long-term maintenance of productivity of Tijuana estuary through nutrient retention and maintenance of marsh surface elevation. The potential exists, however, for predicted accelerated rates of sea-level rise to out-pace marsh surface elevation gain during extended periods of drought (i.e. low sediment inputs) which are not uncommon for this arid region.

Cahoon, D.R.; Lynch, J.C.; Powell, A.N.

1996-01-01

364

Sulfate reduction in Louisiana marsh soils of varying salinities  

Microsoft Academic Search

Potential sulfate reduction and in situ hydrogen sulfide emission rates for three Louisiana marsh soils of varying salinities (salt, brackish, and freshwater) were used to evaluate the influence of soil physicochemical parameters on sulfur transformations in different seasons (summer, winter, and spring). Solid adsorbent preconcentration and emission flux chambers were used in field experiments to measure hydrogen sulfide emissions. Soil

Ronald D. DeLaune; Istvan Devai; Carl R. Crozier; Peter Kelle

2002-01-01

365

Development of an ecohydrological salt marsh model  

EPA Science Inventory

Terrestrial nitrogen input to coastal waters is a critical water quality problem nationwide. Even in systems well described experimentally, a clear understanding of process-level hydrological and biogeochemical controls can be difficult to ascertain from data alone. For examp...

366

Radium fluxes from a salt marsh  

Microsoft Academic Search

Dissolved 226Ra (half life 1,600 yr), 228Ra (half life 5.7 yr) and 224Ra (half life 3.64 days) activities in estuarine and coastal waters higher than values reported for open ocean or river waters have been explained by desorption and diffusion of radium from coastal and estuarine sediments1-4. Fluxes of radium isotopes from sediments in Long Island Sound, the Hudson River

Marsha S. Bollinger; Willard S. Moore

1984-01-01

367

Regeneration of coastal marsh vegetation impacted by hurricanes Katrina and Rita  

USGS Publications Warehouse

The dynamics of plant regeneration via seed and vegetative spread in coastal wetlands dictate the nature of community reassembly that takes place after hurricanes or sea level rise. The objectives of my project were to evaluate the potential effects of saltwater intrusion and flooding of Hurricanes Katrina and Rita on seedling regeneration in coastal wetlands of the Gulf Coast. Specifically I tested hypotheses to determine for species in fresh, brackish and salt marshes of the Gulf Coast if 1) the pattern of seed germination and seedling recruitment differed with distance from the shoreline, and 2) seed germination and seedling recruitment for various species were reduced in higher levels of water depth and salinity. Regarding Hypothesis 1, seedling densities increased with distance from the shoreline in fresh and brackish water marshes while decreasing with distance from the shoreline in salt marshes. Also to test Hypothesis 1, I used a greenhouse seed bank assay to examine seed germination from seed banks collected at distances from the shoreline in response to various water depths and salinity levels using a nested factorial design. For all marsh types, the influence of water level and salinity on seed germination shifted with distance from the shoreline (i.e., three way interaction of the main effects of distance nested within site, water depth, and salinity). Data from the seed bank assay were also used to test Hypothesis 2. The regeneration of species from fresh, brackish, and salt marshes were reduced in conditions of high salinity and/or water, so that following hurricanes or sea level rise, seedling regeneration could be reduced. Among the species of these coastal marshes, there was some flexibility of response, so that at least some species were able to germinate in either high or low salinity. Salt marshes had a few fresher marsh species in the seed bank that would not germinate without a period of fresh water input (e.g., Sagittaria lancifolia) as well as salt water species (e.g., Avicennia germinans, Salicornia bigelovii). Nevertheless, the species richness of seeds germinating from the seed bank of freshwater marshes was reduced more than in salt marshes, indicating that freshwater marsh regeneration may be more affected by hurricanes and/or sea level rise than salt marshes. From the perspective of short-term seed germination and recruitment following hurricanes, species recruitment is dependent on the post-disturbance conditions of water and salinity. ?? 2009 The Society of Wetland Scientists.

Middleton, B. A.

2009-01-01

368

Structural marsh management research priorities  

USGS Publications Warehouse

The paper presents a prioritized list of research issues related to structural marsh management developed by a multidisciplinary panel of regulatory agency representatives, landowners, and scientists. More than 75 issues were identified concerning landscape changes, influence on ecological processes (i.e., hydrologic, biologic, and edaphic factors), habitat quality, cumulative impacts, and management approach. These issues were prioritized and organized around six basic questions regulatory personnel must try to answer for each marsh management plan application. The six questions deal with the influence of marsh management on, in order of most immediate need, marsh loss and health, fisheries, wildlife, habitat change, water quality, and cumulative effects.

Cahoon, Donald, R.; Groat, Charles, G.

1989-01-01

369

Interspecific differences in dead plant buffering capacity alter the impact of acid rain on decomposition rates in tidal marshes  

Microsoft Academic Search

Simulated acid rain did not alter respiration rates of microbial associations on dead Spartina alterniora from Delaware salt marshes or on dead Carex lyngbyei from Oregon brackish marshes. Since these dead plant-microbe associations have a strong buffering capacity for acid rain, the microbial associations did not experience a low pH. In contrast, Phragmites australis has a low buffering capacity and

John L. Gallagher; Lisa A. Donovan; Donna M. Grant; Debra M. Decker

1987-01-01

370

A space-for-time substitution reveals the long-term decline in genotypic diversity of a widespread salt marsh plant, Spartina alterniflora, over a span of 1500 years  

Microsoft Academic Search

Summary 1 Clonal populations face a trade-off between sexual recruitment and vegetative growth and, once established, may undergo continuous declines in genotypic diversity if their sexual recruits make poor competitors. The geological history of delta formation in the Lower Mississippi River Valley was used to age eight S. alterniflora marshes for use in a space-for-time substitution ranging over 1500 years,

STEVEN E. TRAVIS; MARK W. HESTER

2005-01-01

371

Nutrient Cycling in Piermont Marsh  

NASA Astrophysics Data System (ADS)

We investigate the cycling of nutrients through a brackish tidal wetland about 40 km north of Manhattan in the Hudson River estuary. As part of a long-term ecological study of Piermont Marsh, a NOAA reference wetland managed by the NY State DEC, we are measuring dissolved inorganic nutrients on the Marsh surface and its drainage channels. The marsh occupies 400 acres along the southwest corner of Haverstraw Bay with approximately 2 km frontage to the estuary. It is supplied with nutrient-rich water and drained primarily along several tidal creeks and the hundreds of rivulets that feed them. During most tidal cycles the silty berm bounding the marsh is not topped. Human influence in the marsh's surrounding area has had profound effects, one of the most fundamental of which has been the shift from native grass species, predominantly Spartina alterniflora, to an invasive genotype of common reed, Phragmites australis. Along with this shift there have been changes in the root bed, the effective marsh interior and berm heights, the hydroperiod and, as a result, the ability of the marsh to be utilized by various types of Hudson estuary fish. The vegetative shift is believed to be anthropogenic, but the connection is not well understood, and it is not known what role biogeochemical perturbations are playing. We present two field seasons of nitrate, phosphate and silicate measurements from Sparkill Creek, a freshwater stream draining the surrounding highlands constitutes the northern boundary, two tidally driven creeks transect the Marsh from West to East: the Crumkill and an unnamed creek we have dubbed the "Tidal", Ludlow Ditch, a no-longer-maintained drainage channel grading gently from the northern part of the marsh to the South terminates in a wide tidal outlet that is its southern boundary. Net tidal cycle fluxes and fluxes resulting from runoff events are presented. Deviations from Redfield ratios and limiting nutrients are analyzed. Piermont Marsh data is compared to prior studies of the other three NOAA-managed reference marshes in the Hudson Valley. The data supplements carbon content data (presented in a companion poster) to estimate the carbon cycling and sequestration capacity of the Marsh sediments. Nutrient data is being collected as one component of a broad ecological and geochemical study of the Marsh and its adaptation to human influence (see companion posters on carbon cycling and habitat utilization in the Marsh). All data were collected and analyzed as part of Lamont-Doherty Secondary School Field Research Program, which engages NYC high school teachers and students in research in the Hudson/Raritan estuarine environment.

Reyes, N.; Gribbin, S.; Newton, R.; Diaz, K.; Laporte, N.; Trivino, G.; Ortega, J.; McKee, K.; Sambrotto, R.

2011-12-01

372

78 FR 1246 - Otay River Estuary Restoration Project; South San Diego Bay Unit and Sweetwater Marsh Unit of the...  

Federal Register 2010, 2011, 2012, 2013

...FXRS12610800000-134-FF08RSDC00] Otay River Estuary Restoration Project; South San Diego Bay Unit...for the proposed Otay River Estuary Restoration Project. As originally proposed, the project involved the restoration of estuarine and salt marsh...

2013-01-08

373

Ecology of tidal freshwater marshes of the United States east coast: a community profile  

SciTech Connect

Tidal freshwater marshes are a distinctive type of estuarine ecosystem located upstream from tidal saline marshes and downstream from non-tidal freshwater marshes. They are characterized by freshwater or nearly freshwater conditions most of the time, flora and fauna dominated by freshwater species, and daily lunar tidal flushing. This report examines the ecology of this community as it occurs along the Atlantic seaboard from southern New England to northern Florida. This marsh community is heavily influenced by river flow, which maintains freshwater conditions and deposits sediments high in silt and clay. The plant assemblage in tidal freshwater marshes is diverse both in numbers of species and structural plant types. Plant community structure is markedly diverse spatially and seasonally, and reflects the dynamic processing of energy and biomass in the marsh through high productivity, rapid decomposition and seasonal nutrient cycling. The diverse niches in this heterogeneous environment are exploited by a very diverse animal community of as many as 125 species of fish, 102 species of amphibians and reptiles, 280 species of birds, and 46 species of mammals over the community's broad range. Although fewer species are permanent residents or marsh breeders, use of his community for food and cover is high. This use, coupled with the marshes' capacity to be natural buffers and water filters, argue for their high value as natural resources. 349 references, 31 figures, 24 tables.

Odum, W.E.; Smith, T.J. III; Hoover, J.K.; McIvor, C.C.

1984-01-01

374

In Situ Burning Restores the Ecological Function and Structure of an Oil-Impacted Coastal Marsh  

NASA Astrophysics Data System (ADS)

As the use of in situ burning for oil spill remediation in coastal wetlands accelerates, the capacity of this procedure to restore the ecological structure and function of oil-impacted wetlands becomes increasingly important. Thus, our research focused on evaluating the functional and structural recovery of a coastal marsh in South Louisiana to an in situ burn following a Hurricane Katrina-induced oil spill. Permanent sampling plots were set up to monitor marsh recovery in the oiled and burned areas as well as non-oiled and non-burned (reference) marshes. Plots were monitored for species composition, stem density, above- and belowground productivity, marsh resiliency, soil chemistry, soil residual oil, and organic matter decomposition. The burn removed the majority of the oil from the marsh, and structurally the marsh recovered rapidly. Plant biomass and species composition returned to control levels within 9 months; however, species richness remained somewhat lower in the oiled and burned areas compared to the reference areas. Recovery of ecological function was also rapid following the in situ burn. Aboveground and belowground plant productivity recovered within one growing season, and although decomposition rates were initially higher in the oiled areas, over time they became equivalent to those in reference sites. Also, marsh resiliency, i.e., the rate of recovery from our applied disturbances, was not affected by the in situ burn. We conclude that in situ burning is an effective way to remove oil and allow ecosystem recovery in coastal marshes.

Baustian, Joseph; Mendelssohn, Irving; Lin, Qianxin; Rapp, John

2010-11-01

375

COMPARISON OF RIBBED MUSSEL POPULATIONS IN MARSHES SUBJECT TO INCREASING LAND USAGE AND NUTRIENT LOADING  

EPA Science Inventory

Abstract: Narragansett Bay salt marshes of similar geomorphology and hydrology were clustered into low, medium and high human impact based on land use and nutrient inputs. We measured abundance, condition index (CI) and growth of ribbed mussels (Geukensia demissa) from 10 salt ma...

376

Paleoenvironmental History of JoCo Marsh, Jamaica Bay, New York  

NASA Technical Reports Server (NTRS)

Sediment cores from JoCo Marsh, located in Jamaica Bay, NY were analyzed for plant macrofossil and foraminifera records. These records reflect changes in vegetation, sea level, climate and human intervention. Better understanding of past environmental changes provides information for future preservation and protection of the estuary. A 2.81 m core was retrieved from JoCo, a high marsh area located on the eastern side of Jamaica Bay. The lithology of the core differs from high levels of sand, with small amounts of clay, in the bottom 0.8 meters, to salt marsh peat in the upper 2 meters of the core. Basal wood in the sand was dated to about 2060 yr BP. Elphidium foraminifera dominate the basal sands, along with Scirpus seeds, wood, and charcoal. These sands include fish scales which are tentatively identified as killifish, suggesting shallow pools. The transition to marsh peat is dominated by sedge seeds, and declines in charcoal. The peat appears to be dominated by salt marsh grasses. At 2 m the foraminifera change to include mainly Trochammina species and other undifferentiated agglutinates. The upper portion of the core is dominated by Salicornia seeds along with Trochammina and Miliammina or Quinqueloculia. The history of this marsh will be integrated with other records of marsh environmental change along the US eastern seaboard.

Liberman, Louisa; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

2001-01-01

377

Water use characteristics of black mangrove (Avicennia germinans) communities along an ecotone with marsh at a northern geographical limit  

USGS Publications Warehouse

Mangroves are expanding into warm temperate-zone salt marsh communities in several locations globally. Although scientists have discovered that expansion might have modest effects on ecosystem functioning, water use characteristics have not been assessed relative to this transition. We measured early growing season sapflow (Js) and leaf transpiration (Tr) in Avicennia germinans at a latitudinal limit along the northern Gulf of Mexico (Louisiana, United States) under both flooded and drained states and used these data to scale vegetation water use responses in comparison with Spartina alterniflora. We discovered strong convergence when using either Js or Tr for determining individual tree water use, indicating tight connection between transpiration and xylem water movement in small Avicennia trees. When Tr data were combined with leaf area indices for the region with the use of three separate approaches, we determined that Avicennia stands use approximately 1·0–1·3?mm?d–1 less water than Spartina marsh. Differences were only significant with the use of two of the three approaches, but are suggestive of net conservation of water as Avicennia expands into Spartina marshes at this location. Average Js for Avicennia trees was not influenced by flooding, but maximum Js was greater when sites were flooded. Avicennia and Spartina closest to open water (shoreline) used more water than interior locations of the same assemblages by an average of 1·3?mm?d?1. Lower water use by Avicennia may indicate a greater overall resilience to drought relative to Spartina, such that aperiodic drought may interact with warmer winter temperatures to facilitate expansion of Avicennia in some years.

Krauss, Ken W.; McKee, Karen L.; Hester, Mark W.

2014-01-01

378

Grays Lake Ecosystem  

NSDL National Science Digital Library

This case study looks at the marsh ecosystem of Grays Lake in southeast Idaho, and is hosted by the Northern Prairie Wildlife Research Center (NPWRC). Grays Lake has been the focus of numerous research studies to understand factors affecting breeding water birds, habitat management practices, populations, and geological factors. This report gives general information about the Grays Lake ecosystem, including climate, habitats, plant communities, wildlife, water, and geology. More specific details are given through flora and fauna lists, historical and cultural overviews, details about the Grays Lake National Wildlife Refuge, and research information on management of wetlands.

379

Impacts of intensified agriculture developments on marsh wetlands.  

PubMed

A spatiotemporal analysis on the changes in the marsh landscape in the Honghe National Nature Reserve, a Ramsar reserve, and the surrounding farms in the core area of the Sanjiang Plain during the past 30 years was conducted by integrating field survey work with remote sensing techniques. The results indicated that intensified agricultural development had transformed a unique natural marsh landscape into an agricultural landscape during the past 30 years. Ninety percent of the natural marsh wetlands have been lost, and the areas of the other natural landscapes have decreased very rapidly. Most dry farmland had been replaced by paddy fields during the progressive change of the natural landscape to a farm landscape. Attempts of current Chinese institutions in preserving natural wetlands have achieved limited success. Few marsh wetlands have remained healthy, even after the establishment of the nature reserve. Their ecological qualities have been declining in response to the increasing threats to the remaining wetland habitats. Irrigation projects play a key role in such threats. Therefore, the sustainability of the natural wetland ecosystems is being threatened by increased regional agricultural development which reduced the number of wetland ecotypes and damaged the ecological quality. PMID:24027441

Luan, Zhaoqing; Zhou, Demin

2013-01-01

380

Effects of Mosquito Control Ditching on Estuarine Ecosystems.  

National Technical Information Service (NTIS)

Large areas of irregularly flooded North Carolina salt marsh dominated by Juncus roemerianus were ditched in an attempt to control mosquito breeding. Comparative study of ditched and unditched marshes at three locations in N.C., was carried out to determi...

E. J. Kuenzler H. L. Marshall

1973-01-01

381

Tidal Marsh Outwelling of Dissolved Organic Matter and Resulting Temporal Variability in Coastal Water Optical and Biogeochemical Properties  

NASA Technical Reports Server (NTRS)

Coastal wetlands are highly dynamic environments at the land-ocean interface where human activities, short-term physical forcings and intense episodic events result in high biological and chemical variability. Long being recognized as among the most productive ecosystems in the world, tidally-influenced coastal marshes are hot spots of biogeochemical transformation and exchange. High temporal resolution observations that we performed in several marsh-estuarine systems of the Chesapeake Bay revealed significant variability in water optical and biogeochemical characteristics at hourly time scales, associated with tidally-driven hydrology. Water in the tidal creek draining each marsh was sampled every hour during several semi-diurnal tidal cycles using ISCO automated samplers. Measurements showed that water leaving the marsh during ebbing tide was consistently enriched in dissolved organic carbon (DOC), frequently by more than a factor of two, compared to water entering the marsh during flooding tide. Estimates of DOC fluxes showed a net DOC export from the marsh to the estuary during seasons of both low and high biomass of marsh vegetation. Chlorophyll amounts were typically lower in the water draining the marsh, compared to that entering the marsh during flooding tide, suggesting that marshes act as transformers of particulate to dissolved organic matter. Moreover, detailed optical and compositional analyses demonstrated that marshes are important sources of optically and chemically distinctive, relatively complex, high molecular weight, aromatic-rich and highly colored dissolved organic compounds. Compared to adjacent estuarine waters, marsh-exported colored dissolved organic matter (CDOM) was characterized by considerably stronger absorption (more than a factor of three in some cases), larger DOC-specific absorption, lower exponential spectral slope, larger fluorescence signal, lower fluorescence per unit absorbance, and higher fluorescence at visible wavelengths. Observed patterns in water optical and biogeochemical variables were very consistent among different marsh systems and throughout the year, despite continued tidal exchange, implying rapid transformation of marsh DOM in the estuary through both photochemical and microbial processes. These findings illustrate the importance of tidal marsh ecosystems as sources, sinks and/or transformers of biologically important nutrients, carbon and colored dissolved organic compounds, and their influence on short-term biological, optical and biogeochemical variability in coastal waters.

Tzortziou, Maria; Neale, Patrick J.; Megonigal, J. Patrick; Butterworth, Megan; Jaffe, Rudolf; Yamashita, Youhei

2010-01-01

382

Aboveground Allometric Models for Freeze-Affected Black Mangroves (Avicennia germinans): Equations for a Climate Sensitive Mangrove-Marsh Ecotone.  

PubMed

Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone. PMID:24971938

Osland, Michael J; Day, Richard H; Larriviere, Jack C; From, Andrew S

2014-01-01

383

Aboveground Allometric Models for Freeze-Affected Black Mangroves (Avicennia germinans): Equations for a Climate Sensitive Mangrove-Marsh Ecotone  

PubMed Central

Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

Osland, Michael J.; Day, Richard H.; Larriviere, Jack C.; From, Andrew S.

2014-01-01

384

Marine Ecosystems  

NSDL National Science Digital Library

In the wild, small crustaceans known as brine shrimp live in marine habitats such as saltwater lakes. In this activity, learners create a saltwater or marine ecosystem that becomes an experimental brine shrimp hatchery. Learners observe the brine shrimp life cycle and test the effect of salinity (salt content) on brine shrimp eggs and larvae, as well as consider the potential impact of other variables such as water temperature and pollution.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

385

Gut contents of common mummichogs, Fundulus heteroclitus L., in a restored impounded marsh and in natural reference marshes  

Microsoft Academic Search

We examined the gut contents of mummichogs, Fundulus heteroclitus L., entering and leaving ditches in three marsh regions within the Barn Island Wildlife Management Area in Connecticut: a\\u000a restored impounded valley marsh, a marsh below the impoundment dike (Headquarters Marsh), and an unimpounded valley marsh\\u000a (Davis Marsh). On the Headquarters Marsh and at certain times on the other two marshes,

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

1994-01-01

386

Effects of environmental changes on marsh vegetation with special reference to salinity  

NASA Technical Reports Server (NTRS)

A literature survey primarily concerned with brackish and salt marshes located along the eastern coast of North America and the Gulf Coast was presented. The review concentrated upon the vegetation of the marshes, particularly in regard to distribution, composition, succession, and productivity. Special efforts were made to include major works concerned with the Louisiana and Mississipi coastal marshes. It appears that spring to early summer (weeks 18-34 of the year; April - mid-July) is the best period of time to categorize the communities. It is during this time of the year that the communities appear most stable in regard to species composition. This allows a strong correlation to be drawn between the salinity of the region and the dominant species of the community. As such, this would seem to be best period in which to sample the marsh via air or land for differences in vegetation and salinity.

Smalley, A. E.; Thien, L. B.

1976-01-01

387

On incorporating fire into our thinking about natural ecosystems: A response to Saha and Howe  

USGS Publications Warehouse

The distribution and abundance of the red-jointed fiddler crab, Uca minax, was related to the distribution of marsh plants within a Virginia estuary. The crab was found in association with 15 species of marsh phanerogams, occurring with five plant species more than 20 percent of the time. These plants were Spartina alterniflora, Scirpus robustus, Distichlis spicata, Spartina patens, and Spartina cynosuroides. Densities ranged from 0-76 burrows per square meter, mean densities being 7.88 within the brackish-water marsh and 14.35 within the salt-water marsh. The crab was not obtained by sampling the freshwater marsh.

Keeley, J. E.; Bond, W. J.

2001-01-01

388

Ambient and potential denitrification rates in marsh soils of Northeast Creek and Bass Harbor Marsh watersheds, Mount Desert Island, Maine  

USGS Publications Warehouse

Nutrient enrichment from atmospheric deposition, agricultural activities, wildlife, and domestic sources is a concern at Acadia National Park on Mount Desert Island, Maine, because of the potential problems of degradation of water quality and eutrophication in estuaries. Degradation of water quality has been observed at Bass Harbor Marsh estuary in the park but only minimally in Northeast Creek estuary. Previous studies at Acadia National Park have estimated nutrient inputs to estuaries from atmospheric deposition and surface-water runoff, and have identified shallow groundwater as an additional potential source of nutrients. Previous studies at Acadia National Park have assumed that a certain fraction of the nitrogen input was removed through microbial denitrification, but rates of denitrification (natural or maximum potential) in marsh soils have not been determined. The U.S. Geological Survey, in cooperation with Acadia National Park, measured in-place denitrification rates in marsh soils in Northeast Creek and in Bass Harbor Marsh watersheds during summer 2008 and summer 2009. Denitrification was measured under ambient conditions as well as after additions of inorganic nitrogen and glucose. In-place denitrification rates under ambient conditions were similar to those reported for other coastal wetlands, although they were generally lower than those reported for salt marshes having high ambient concentrations of nitrate (NO3). Denitrification rates generally increased by at least an order of magnitude following NO3 additions, with or without glucose (as the carbohydrate) additions, compared with the ambient treatments that received no nutrient additions. The treatment that added both glucose and NO3 resulted in a variety of denitrification responses when compared with the addition of NO3 alone. In most cases, the addition of glucose to a given rate of NO3 addition resulted in higher rates of denitrification. These variable responses indicate that the amount of labile carbohydrates can limit denitrification even if NO3 is present. For most sites in both watersheds, the maximum denitrification rates ranged from of 150 to 900 micromoles of nitrous oxide per square meter per hour. These rates were equivalent to the release of 37 to 221 grams of nitrogen per square meter per year. Weak positive correlations were observed for soil temperature and for measured ammonium concentration in groundwater. Weak negative correlations were observed between denitrification rate and water level and specific conductance. The rates of denitrification in Bass Harbor Marsh and Northeast Creek under ambient conditions, both of which were relatively low, indicate that NO3 availability is low in both systems. It is evident from the addition of combined treatments of NO3 and glucose that these marsh soils are capable of comparatively high rates of denitrification, therefore, estuarine eutrophication is not a result of nitrogen inputs to marsh soils that are in excess of the denitrification capacity in these systems. If terrestrial inputs to the estuary are the cause of the observed eutrophic condition in Bass Harbor Marsh, then these inputs to the estuary must bypass the marsh in channelized surface flow, or perhaps they circumvent the marsh in shallow groundwater seepage along subsurface pathways that enter the estuary directly.

Huntington, Thomas G.; Culbertson, Charles W.; Duff, John H.

2012-01-01

389

A modeling study of the dynamics of pore water seepage from intertidal marsh sediments  

Microsoft Academic Search

A numerical boundary integral equation model has been used to simulate tidally driven transient variations in pore water seepage from salt marsh sediments into tidal channels and its subsequent recharge by tidal inundation. In general the results show that the maximum seepage discharge occurs at or near the intersection of the creek bank and the channel water surface. Over a

Leonard Robert Gardner

2005-01-01

390

RIBBED MUSSEL NITROGEN ISOTOPE SIGNATURES REFLECT NITROGEN SOURCES IN COASTAL MARSHES  

EPA Science Inventory

The stable nitrogen isotope ratio in tissue of the ribbed mussel (Geukensia demissa) was investigated as an indicator of the source of nitrogen inputs to coastal salt marshes. Initially, mussels were fed a diet of 15N-enriched algae in the laboratory to determine how the tissue n...

391

Hydrology in a peaty high marsh: hysteretic flow and biogeochemical implications  

EPA Science Inventory

Terrestrial nutrient input to coastal waters is a critical water quality problem worldwide, and salt marshes may provide a valuable nutrient buffer (either by removal or by smoothing out pulse inputs) between terrestrial sources and sensitive estuarine habitats. One of the major...

392

Qualitative community stability determines parasite establishment and richness in estuarine marshes  

PubMed Central

The establishment of parasites with complex life cycles is generally thought to be regulated by free-living species richness and the stability of local ecological interactions. In this study, we test the prediction that stable host communities are prerequisite for the establishment of complex multi-host parasite life cycles. The colonization of naïve killifish, Fundulus heteroclitus, by parasites was investigated in 4 salt marsh sites that differed in time since major ecological restoration, and which provided a gradient in free-living species richness. The richness of the parasite community, and the rate at which parasite species accumulated in the killifish, were similar between the low diversity unrestored site and the two high diversity (10- and 20-year) restored marsh sites. The parasite community in the newly restored marsh (0 year) included only directly-transmitted parasite species. To explain the paradox of a low diversity, highly invaded salt marsh (unrestored) having the same parasite community as highly diverse restored marsh sites (10 and 20 yrs) we assessed qualitative community stability. We find a significant correlation between system stability and parasite species richness. These data suggest a role for local stability in parasite community assembly, and support the idea that stable trophic relationships are required for the persistence of complex parasite life cycles.

Sukhdeo, Michael V.K.

2013-01-01

393

Vegetation engineers marsh morphology through multiple competing stable states  

PubMed Central

Marshes display impressive biogeomorphic features, such as zonation, a mosaic of extensive vegetation patches of rather uniform composition, exhibiting sharp transitions in the presence of extremely small topographic gradients. Although generally associated with the accretion processes necessary for marshes to keep up with relative sea level rise, competing environmental constraints, and ecologic controls, zonation is still poorly understood in terms of the underlying biogeomorphic mechanisms. Here we find, through observations and modeling interpretation, that zonation is the result of coupled geomorphological–biological dynamics and that it stems from the ability of vegetation to actively engineer the landscape by tuning soil elevation within preferential ranges of optimal adaptation. We find multiple peaks in the frequency distribution of observed topographic elevation and identify them as the signature of biologic controls on geomorphodynamics through competing stable states modulated by the interplay of inorganic and organic deposition. Interestingly, the stable biogeomorphic equilibria correspond to suboptimal rates of biomass production, a result coherent with recent observations. The emerging biogeomorphic structures may display varying degrees of robustness to changes in the rate of sea level rise and sediment availability, with implications for the overall resilience of marsh ecosystems to climatic changes.

Marani, Marco; Da Lio, Cristina; D'Alpaos, Andrea

2013-01-01

394

Comparison of aerated marsh-pond-marsh and continuous marsh constructed wetlands for treating swine wastewater.  

PubMed

Increased swine production in North Carolina has resulted in greater waste generation and is demanding some emerging new innovative technologies to effectively treat swine wastewater. One of the cost-effective and passive methods to treat swine wastewater is using constructed wetlands. The objective of this study was to evaluate the N removal under two N loads in 3 different wetland systems: aerated marsh-pond-marsh (M-P-M), aerated marsh-covered pond-marsh (M-FB-M), and continuous marsh (CM) with two days drain and five days flood cycle. Swine wastewater from an anaerobic lagoon was applied to the constructed wetland cells (11 m wide x 40 m length) at two N loading rates of 7 and 12 kg N ha(-1) day(-1)from June to July and August to September 2005, respectively. Weekly inflow and outflow samples were collected for N, P, TS, and COD analysis. Total N reductions (%) at low and high N loading rates were 85.8 and 51.8; 86.3 and 63.3; and 86.2 and 61.8 for M-P-M, M-FB-M, and CM, respectively. Aeration had no significant (P > 0.05) impact on N removal. However, significant (P < 0.05) differences were observed for wetland systems between low and high N loading rates. No difference (P > 0.05) in N reduction was found among wetland systems. Vegetation uptake of N was negligible, ranging from 1.2 to 1.8 %. No significant (P > 0.05) differences in TS and COD removal were observed between the wetland systems. PMID:20401775

Forbes, Dean A; Reddy, G B; Hunt, Patrick G; Poach, M E; Ro, Kyoung S; Cyrus, Johnsely S

2010-01-01

395

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design  

PubMed Central

Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM) had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. Methods The following parameters were evaluated using "Before-After-Control-Impact" (BACI) design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. Results The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment areas led to a significant decrease (~44%) in the number of times when the larviciding threshold was reached. This reduction, in turn, resulted in a significant decrease (~74%) in the number of larvicide applications in the treatment areas post-project. The remaining larval habitat in the treatment areas had a different geographic distribution and was largely confined to the restored marsh surface (i.e. filled-in mosquito ditches); however only ~21% of the restored marsh surface supported mosquito production. Conclusion The geostatistical analysis showed that OMWM demonstrated considerable potential for effective mosquito control and compatibility with other natural resource management goals such as restoration, wildlife habitat enhancement, and invasive species abatement. GPS and GIS tools are invaluable for large scale project design, data collection, and data analysis, with geostatistical methods serving as an alternative or a supplement to the conventional inference statistics in evaluating the project outcome.

Rochlin, Ilia; Iwanejko, Tom; Dempsey, Mary E; Ninivaggi, Dominick V

2009-01-01

396

Sensitivity analysis of the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER)  

Microsoft Academic Search

The San Francisco Estuary contains the largest extent of tidal marsh in the western United States. It is home to several state and federally listed species that are threatened or endangered. Climate change is a potential threat to these tidal marsh habitats through accelerated sea-level rise. The Wetland Accretion Rate Model for Ecosystem Resilience, or WARMER, is a 1-D vertical

K. Swanson; J. Z. Drexler; D. H. Schoellhamer; K. Thorne; K. Spragens; J. Takekawa

2010-01-01

397

Distribution of seed plants with respect to tide levels and water salinity in the natural tidal marshes of the northern San Francisco Bay Estuary, California  

USGS Publications Warehouse

Shoaling of subtidal and intertidal mud flats has permitted tidal marshes to spread across large marginal areas of the San Francisco Bay estuary during the past several thousand years. By 1850 A.D. the tidal marshes of the estuary, including those of the Sacramento - San Joaquin Delta, covered an area nearly twice as large as the area of open water. Nearly 95 percent of these marshes have been diked or filled during the past 125 years. Species distributions along leveled transects at six tidal marshes indicate that elevation and water salinity are the principal ecological factors that-control the distribution of seed plants in the remaining natural tidal marshes of the northern San Francisco Bay estuary. Marsh surfaces situated near mean tide level are populated by robust monocotyledons (e.g., Spartina foliosa, Scirpus californicus), whereas surfaces situated near high-tide levels support dicotyledons and a few small monocotyledonous species (e.g., Salicornia virginica, Distichlis spicata). Marshes near the seaward end of the estuary are typically occupied by 10-15 salt-tolerant species (e.g., Spartina foliosa, Salicornia virginica), whereas marshes at the riverward end of the estuary are inhabited by as many as 30 species, most of which are known to tolerate moderate or small amounts of salt (e.g., Scirpus spp., Phragmites communis, Typha latifolia).

Atwater, Brian F.; Hedel, Charles W.

1976-01-01

398

8. View of Sterling Creek Marsh looking northeast across the ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. View of Sterling Creek Marsh looking northeast across the berm with the marsh to the left - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

399

9. View of Sterling Creek Marsh looking southwest, with the ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. View of Sterling Creek Marsh looking southwest, with the marsh in the background and the berm in the foreground - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

400

10. View of Sterling Creek Marsh looking south with house ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. View of Sterling Creek Marsh looking south with house in the background and marsh in foreground - Richmond Hill Plantation, Sterling Creek Marsh, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

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