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1

The nitrogen budget of a salt marsh ecosystem  

Microsoft Academic Search

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

Ivan Valiela; John M. Teal

1979-01-01

2

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

3

Pyrite: its rapid formation in a salt marsh and its importance in ecosystem metabolism  

Microsoft Academic Search

Pyrite formation in salt-marsh peat occurs more rapidly than is generally thought for any natural system. Pyrite is the major end product of sulfate reduction, and sulfate reduction is the major form of respiration in the salt-marsh ecosystem. When the rapid formation of pyrite is ignored, the rates of sulfate reduction and ecosystem respiration may be grossly underestimated.

R. W. HOWARTH

1979-01-01

4

Salt Marshes at Chincoteague Island  

USGS Multimedia Gallery

Salt marshes at Chincoteague Island. The salt marshes that make up Chincoteague Island are important habitat for migrating waterfowl. In addition, they serve an important role in protecting inland ecosystems and communities from oceanic storms....

5

Salt Marsh  

NSDL National Science Digital Library

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

6

Whole ecosystem estimates of carbon exchange and storage in a New England salt marsh  

NASA Astrophysics Data System (ADS)

Salt marshes are wetlands situated at the interface of land and ocean. They are among the most productive ecosystems worldwide and store substantial amounts of carbon as peat. Their long-term stability is dependent on sediment accretion and carbon accumulation to avoid submergence when sea level is rising. Currently, estimates of carbon storage in salt marshes are uncertain because our understanding of the coupling between marsh plant productivity and carbon release to the adjacent ocean is limited. To evaluate the capacity to store carbon as well as the resilience of the ecosystem, long-term studies of carbon cycling considering both vertical and lateral fluxes are necessary. To study the net exchange between marsh and atmosphere, we chose the non-intrusive eddy covariance which allows nearly continuous half hourly flux measurements of net ecosystem exchange (NEE) on the ecosystem scale. Since spring 2012, we have been investigating the marsh-atmosphere exchange of carbon dioxide (CO2) at a Spartina patens high marsh at the Plum Island Ecosystems Long-Term Ecological Research site. Seasonal dynamics of CO2 exchange during summer were controlled by the phenology of S. patens. Preliminary estimates for seasonal carbon storage range from 185 to 228 g C m-2 (5/1/2012 to 10/31/2012). During the winter months we observed small fluxes, but carbon uptake still occurred during the day. We attribute this to microalgae productivity. Winter carbon release is estimated to be approximately 130 g C m-2 (12/6/2012 to 4/30/2013), when uptake by microalgae is not taken into account. This emphasizes the relevance of transitional and cold season carbon cycling for the carbon storage capacity of northern salt marshes, since a large proportion of fixed carbon is released during these periods. Direct tidal effects on the marsh-atmosphere carbon exchange are visible especially during monthly spring tides, when both daytime carbon uptake and night time respiration were reduced during flooding. To partition the net flux into its component fluxes gross primary production (GPP) and ecosystem respiration (Reco), these tidal influences have to be incorporated in the NEE model. Differences in GPP and Reco during high tide and low tide events can be used to constrain estimates of lateral carbon transport. These will need to be compared to direct measurements of tidal carbon fluxes to determine how much of the reduction in atmospheric fluxes is due to metabolic changes and how much is due to the exchange of carbon between the marsh and water.

Forbrich, I.; Giblin, A.

2013-12-01

7

Salt Marshes at Chincoteague Island  

USGS Multimedia Gallery

Salt marshes at Chincoteague Island. The salt marshes that make up Chincoteague Island are important habitat for migrating waterfowl. In addition, they serve an important role in protecting inland ecosystems and communities from oceanic storms. Mosquito point can be seen in the background where the ...

8

Salt Marshes along Little Mosquito Creek  

USGS Multimedia Gallery

Salt marshes along Little Mosquito Creek of Chincoteague Island. The salt marshes that make up Chincoteague Island are important habitat for migrating waterfowl. In addition, they serve an important role in protecting inland ecosystems and communities from oceanic storms....

9

Chemical and Biological Gradients: Controls on Nitrous Oxide Release in Salt Marsh Ecosystems  

E-print Network

in nitrate and organic matter and low in oxygen (Moseman- Valtierra 2011). This study looks more deeply levels of nitrogen uptake. Salt marshes have been shown to remove upwards of half the terrestrial inorganic nitrogen inputs (Seitzinger 1988). It is important to note that these marshes are known

Vallino, Joseph J.

10

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 ...

11

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. PMID:25071995

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

2014-01-01

12

Flax pond ecosystem study: exchanges of CO/sub 2/ between a salt marsh and the atmosphere  

SciTech Connect

Profiles of CO/sub 2/ concentration, windspeed, and temperature were used in the aerodynamic flux technique to calculate the CO/sub 2/ exchange between a Long Island salt marsh and the atmosphere. Uptake of CO/sub 2/ by the marsh during hours of sunlight and release during the night occurred during all times of the year. The rates of CO/sub 2/ exchange were highest during midsummer, 2.3 g CO/sub 2/.m/sup -2/.h/sup -1/ averaged over the daylight hours of July, and 1.3 g CO/sub 2/.m/sup -2/.h/sup -1/ for both uptake and release. The net 24-h exchange rates followed Spartina growth and senescence during the summer and fall, and photosynthesis of benthic algae during late winter and spring. There was a net uptake of Co/sub 2/ over 24 h by the marsh during all seasons except autumn. The net annual flow of carbon was from the atmosphere to Flax Pond (approx. = 300 g C.m/sup -2/.yr/sup -1/ averaged over the entire marsh ecosystem). This flux was larger than the net exchange of carbon between the marsh and either uplands, sediments, or coastal waters. The net uptake of CO/sub 2/ during summer was less than the net productivity of the vascular plants, indicating that some of the CO/sub 2/ assimilated by the plants came from heterotrophic respiration within the marsh. Nevertheless, respiration by the plants was by far the largest source of CO/sub 2/ from the marsh surface. Nighttime respiration of the ecosystem released a total of approx. = 510 g C.m/sup -2/.yr/sup -1/ to the atmosphere.

Houghton, R.A.; Woodwell, G.M.

1980-12-01

13

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 ...

14

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 ...

15

Flax Pond ecosystem study: exchanges of carbon in water between a salt marsh and Long Island Sound  

Microsoft Academic Search

Flax Pond, a tidal marsh on the north shore of Long Island, New York, was used to examine the exchanges of carbon in its various forms between a salt marsh and the coastal waters. The marsh removed fine particulate carbon from the tidal water throughout the year; it tended to be a small source of C as total COâ and

G. M. Woodwell; D. E. Whitney; C. A. S. Hall; R. A. Houghton

1977-01-01

16

Consumer control of salt marshes driven by human disturbance.  

PubMed

Salt marsh ecosystems are widely considered to be controlled exclusively by bottom-up forces, but there is mounting evidence that human disturbances are triggering consumer control in western Atlantic salt marshes, often with catastrophic consequences. In other marine ecosystems, human disturbances routinely dampen (e.g., coral reefs, sea grass beds) and strengthen (e.g., kelps) consumer control, but current marsh theory predicts little potential interaction between humans and marsh consumers. Thus, human modification of top-down control in salt marshes was not anticipated and was even discounted in current marsh theory, despite loud warnings about the potential for cascading human impacts from work in other marine ecosystems. In spite of recent experiments that have challenged established marsh dogma and demonstrated consumer-driven die-off of salt marsh ecosystems, government agencies and nongovernmental organizations continue to manage marsh die-offs under the old theoretical framework and only consider bottom-up forces as causal agents. This intellectual dependency of many coastal ecologists and managers on system-specific theory (i.e., marsh bottom-up theory) has the potential to have grave repercussions for coastal ecosystem management and conservation in the face of increasing human threats. We stress that marine vascular plant communities (salt marshes, sea grass beds, mangroves) are likely more vulnerable to runaway grazing and consumer-driven collapse than is currently recognized by theory, particularly in low-diversity ecosystems like Atlantic salt marshes. PMID:18577090

Bertness, Mark D; Silliman, Brian R

2008-06-01

17

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

PubMed

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

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

2011-07-01

18

Salt marsh geomorphology: Physical and ecological effects on landform Keywords: salt marsh geomorphology; AGU Chapman Conference  

E-print Network

Editorial Salt marsh geomorphology: Physical and ecological effects on landform Keywords: salt marsh geomorphology; AGU Chapman Conference Evidence that the three-dimensional structure of salt marsh, and the ratio of marsh edge:marsh interior have all been shown to affect the distribution and density of salt

Fagherazzi, Sergio

19

Exotic Spartina alterniflora invasion alters ecosystem-atmosphere exchange of CH4 and N2 O and carbon sequestration in a coastal salt marsh in China.  

PubMed

Coastal salt marshes are sensitive to global climate change and may play an important role in mitigating global warming. To evaluate the impacts of Spartina alterniflora invasion on global warming potential (GWP) in Chinese coastal areas, we measured CH4 and N2 O fluxes and soil organic carbon sequestration rates along a transect of coastal wetlands in Jiangsu province, China, including open water, bare tidal flat, and invasive S. alterniflora, native Suaeda salsa and Phragmites australis marshes. Annual CH4 emissions were estimated as 2.81, 4.16, 4.88, 10.79 and 16.98 kg CH4 ha(-1) for open water, bare tidal flat, and P. australis, S. salsa and S. alterniflora marshes, respectively, indicating that S. alterniflora invasion increased CH4 emissions by 57-505%. In contrast, negative N2 O fluxes were found to be significantly and negatively correlated (P < 0.001) with net ecosystem CO2 exchange during the growing season in S. alterniflora and P. australis marshes. Annual N2 O emissions were 0.24, 0.38 and 0.56 kg N2 O ha(-1) in open water, bare tidal flat and S. salsa marsh, respectively, compared with -0.51 kg N2 O ha(-1) for S. alterniflora marsh and -0.25 kg N2 O ha(-1) for P. australis marsh. The carbon sequestration rate of S. alterniflora marsh amounted to 3.16 Mg C ha(-1) yr(-1) in the top 100 cm soil profile, a value that was 2.63- to 8.78-fold higher than in native plant marshes. The estimated GWP was 1.78, -0.60, -4.09 and -1.14 kg CO2 eq ha(-1) yr(-1) in open water, bare tidal flat, P. australis marsh and S. salsa marsh, respectively, but dropped to -11.30 kg CO2 eq ha(-1) yr(-1) in S. alterniflora marsh. Our results indicate that although S. alterniflora invasion stimulates CH4 emissions, it can efficiently mitigate increases in atmospheric CO2 and N2 O along the coast of China. This article is protected by copyright. All rights reserved. PMID:25367159

Yuan, Junji; Ding, Weixin; Liu, Deyan; Kang, Hojeong; Freeman, Chris; Xiang, Jian; Lin, Yongxin

2014-11-01

20

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

Microsoft Academic Search

In this study two time scales were looked at: a yearlong study was completed, and a 180-day decay experiment was done. Juncus maritimus and Scirpus maritimus have different life cycles, and this seems to have implications in the Hg-contaminated salt marsh sediment chemical environment, namely Eh and pH. In addition, the belowground biomass decomposition rates were faster for J. maritimus, as

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

2011-01-01

21

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

22

NITRATE RELEASE BY SALT MARSH PLANTS: AN OVERLOOKED NUTRIENT FLUX MECHANISM  

EPA Science Inventory

Salt marshes provide water purification as an important ecosystem service in part by storing, transforming and releasing nutrients. This service can be quantified by measuring nutrient fluxes between marshes and surface waters. Many processes drive these fluxes, including photosy...

23

Spatial and temporal patterns of Lycium carolinianum Walt., the Carolina Wolfberry, in the salt marshes of Aransas National Wildlife Refuge, Texas  

E-print Network

Understanding the salt marsh ecosystem in the Guadalupe Estuary is needed because wetlands in this system support the endangered whooping crane (Grus americana). The marsh plant research and monitoring described herein were based in the salt marshes...

Butzler, Rachel Elizabeth

2006-08-16

24

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

25

Experimental predator removal causes rapid salt marsh die-off  

PubMed Central

Salt marsh habitat loss to vegetation die-offs has accelerated throughout the western Atlantic in the last four decades. Recent studies have suggested that eutrophication, pollution and/or disease may contribute to the loss of marsh habitat. In light of recent evidence that predators are important determinants of marsh health in New England, we performed a total predator exclusion experiment. Here, we provide the first experimental evidence that predator depletion can cause salt marsh die-off by releasing the herbivorous crab Sesarma reticulatum from predator control. Excluding predators from a marsh ecosystem for a single growing season resulted in a >100% increase in herbivory and a >150% increase in unvegetated bare space compared to plots with predators. Our results confirm that marshes in this region face multiple, potentially synergistic threats. PMID:24766277

Bertness, Mark D; Brisson, Caitlin P; Coverdale, Tyler C; Bevil, Matt C; Crotty, Sinead M; Suglia, Elena R

2014-01-01

26

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

27

MARSH LAKE, APPLETON, MINNESOTA ECOSYSTEM RESTORATION PROJECT  

E-print Network

MARSH LAKE, APPLETON, MINNESOTA ECOSYSTEM RESTORATION PROJECT 27 SEPTEMBER 2011 ABSTRACT: The purpose of the Project is to restore habitat structure, form and function to Marsh Lake, the upper pool-Federal sponsor. Construction of the Marsh Lake Dam initially began in the late 1930's by the State of Minnesota

US Army Corps of Engineers

28

Final report: Initial ecosystem response of salt marshes to ditch plugging and pool creation: Experiments at Rachel Carson National Wildlife Refuge (Maine)  

USGS Publications Warehouse

This study evaluates the response of three salt marshes, associated with the Rachel Carson National Wildlife Refuge (Maine), to the practice of ditch plugging. Drainage ditches, originally dug to drain the marsh for mosquito control or to facilitate salt hay farming, are plugged with marsh peat in an effort to impound water upstream of the plug, raise water table levels in the marsh, and increase surface water habitat. At two study sites, Moody Marsh and Granite Point Road Marsh, ditch plugs were installed in spring 2000. Monitoring of hydrology, vegetation, nekton and bird utilization, and marsh development processes was conducted in 1999, before ditch plugging, and then in 2000 and 2001 (all parameters except nekton), after ditch plugging. Each study site had a control marsh that was monitored simultaneously with the plugged marsh, and thus, we employed a BACI study design (before, after, control, impact). A third site, Marshall Point Road Marsh, was plugged in 1998. Monitoring of the plugged and control sites was conducted in 1999 and 2000, with limited monitoring in 2001, thus there was no ?before? plug monitoring. With ditch plugging, water table levels increased toward the marsh surface and the areal extent of standing water increased. Responding to a wetter substrate, a vegetation change from high marsh species (e.g., Spartina patens) to those more tolerant of flooded conditions (e.g., Spartina alterniflora) was noted at two of the three ditch plugged sites. Initial response of the nekton community (fishes and decapod crustaceans) was evaluated by monitoring utilization of salt marsh pools using a 1m2 enclosure trap. In general, nekton species richness, density, and community structure remained unchanged following ditch plugging at the Moody and Granite Point sites. At Marshall Point, species richness and density (number of individuals per m2) were significantly greater in the experimental plugged marsh than the control marsh (<2% of the control marsh was open water habitat vs. 11% of the plugged marsh). The response of birds, categorized as waterfowl & waterbirds, shorebirds & wading birds, gulls & terns, and miscellaneous (raptors, passerines, other), was variable. Following ditch plugging, bird species richness increased at the Granite Point site (1999 pre-plug = 15.4, 2000 post-plug = 26.2, 2001 post-plug = 38.7). Because of a low sample size at Moody Marsh, reliable statements on species richness cannot be made. Density of birds (no. of birds per ha) remained unchanged with ditch plugging at Granite Point Marsh, although there was a strong, but not statistically significant, trend toward increased density. This study only reports on initial responses of marsh functions to ditch plugging. Monitoring should continue at these sites, and perhaps at additional sites, for the next decade or so. A monitoring plan is recommended. Long-term monitoring will include evaluation of salt marsh development processes using SET (surface elevation table) methodology. There is concern, although not confirmed, that as ditch-plugged marshes become wetter and marsh grass production declines their ability to keep pace with sea level rise could be jeopardized. It is suggested that ditch plugging should be considered an experimental marsh management technique. Additional monitoring on the physical and habitat responses of ditch-plugged marshes is required, along with assessments of other techniques aimed at restoring open water habitat to the marsh surface.

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

2002-01-01

29

Methylmercury production in a Chesapeake Bay salt marsh  

NASA Astrophysics Data System (ADS)

In a detailed study of the biogeochemical factors affecting the methylation of mercury in a Chesapeake Bay salt marsh, we examined relationships between mercury methylation and numerous variables, including sulfate reduction rates, organic carbon mineralization rates, iron and sulfur chemistry, and the character of dissolved organic matter (DOM). Our data show that salt marshes are important sites of de novo methylmercury (MeHg) production in coastal ecosystems. Some of the controls on MeHg production that have been well-described in other ecosystems also impacted MeHg production in this salt marsh, specifically the effect of sulfide accumulation on mercury bioavailability. We observed some novel biogeochemical relationships with Hg(II)-methylation and MeHg accumulation, particularly the positive association of Hg(II)-methylation with zones of microbial iron reduction. On the basis of this relationship, we suggest caution in wetland and groundwater remediation approaches involving iron additions. Aqueous phase Hg complexation appeared to be the dominant control on Hg bioavailability across the marsh sites examined, rather than Hg partitioning behavior. A detailed examination of DOM character in the marsh suggested a strong positive association between Hg(II)-methylation rate constants and increasing DOM molecular weight. Overall, our results indicate that net MeHg production is controlled by a balance between microbial activity and geochemical effects on mercury bioavailability, but that a significant zone of MeHg production can persist in near surface salt marsh soils. Production of MeHg in coastal marshes may negatively impact ecosystems via export to adjacent estuaries or through direct bioaccumulation in birds, fish and amphibians that feed in these highly productive ecosystems.

Mitchell, Carl P. J.; Gilmour, Cynthia C.

2008-06-01

30

Flax Pond ecosystem study: Exchanges of phosphorus between a salt marsh and the coastal waters of Long Island Sound  

Microsoft Academic Search

The exchanges of phosphorus between the Flax Pond, a tidal Spartina alterniflora marsh on the north shore of Long Island (USA) and Long Island Sound were measured over 18 months. Phosphate was exported from the marsh from May through December and imported during the remainder of the year. Organic phosphorus appears to be accumulated in all seasons, but the yearly

G. M. Woodwell; D. E. Whitney

1977-01-01

31

Wave attenuation over coastal salt marshes under storm surge conditions  

NASA Astrophysics Data System (ADS)

Coastal communities around the world face an increasing risk from flooding as a result of rising sea level, increasing storminess and land subsidence. Salt marshes can act as natural buffer zones, providing protection from waves during storms. However, the effectiveness of marshes in protecting the coastline during extreme events when water levels are at a maximum and waves are highest is poorly understood. Here we experimentally assess wave dissipation under storm surge conditions in a 300-metre-long wave flume tank that contains a transplanted section of natural salt marsh. We find that the presence of marsh vegetation causes considerable wave attenuation, even when water levels and waves are highest. From a comparison with experiments without vegetation, we estimate that up to 60% of observed wave reduction is attributed to vegetation. We also find that although waves progressively flatten and break vegetation stems and thereby reduce dissipation, the marsh substrate remained stable and resistant to surface erosion under all conditions. The effectiveness of storm wave dissipation and the resilience of tidal marshes even at extreme conditions suggest that salt marsh ecosystems can be a valuable component of coastal protection schemes.

Möller, Iris; Kudella, Matthias; Rupprecht, Franziska; Spencer, Tom; Paul, Maike; van Wesenbeeck, Bregje K.; Wolters, Guido; Jensen, Kai; Bouma, Tjeerd J.; Miranda-Lange, Martin; Schimmels, Stefan

2014-10-01

32

Utilization of invasive tamarisk by salt marsh consumers  

Microsoft Academic Search

Plant invasions of coastal wetlands are rapidly changing the structure and function of these systems globally. Alteration\\u000a of litter dynamics represents one of the fundamental impacts of an invasive plant on salt marsh ecosystems. Tamarisk species\\u000a (Tamarix spp.), which extensively invade terrestrial and riparian habitats, have been demonstrated to enter food webs in these ecosystems.\\u000a However, the trophic impacts of

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

2008-01-01

33

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

34

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

35

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

36

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

EPA Science Inventory

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

37

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

38

New York State Salt Marsh Restoration and Monitoring Guidelines  

E-print Network

#12;New York State Salt Marsh Restoration and Monitoring Guidelines prepared by: Nancy L. Niedowski;The Salt Marsh Restoration and Monitoring Guidelines were prepared under the National OceanicState,Division of CoastalResources,41 State Street,Albany, New York 12231. December 2000 #12;PREFACE All salt marsh

39

1 NUMERICAL MODELS OF SALT MARSH 2 EVOLUTION: ECOLOGICAL, GEOMORPHIC,  

E-print Network

1 NUMERICAL MODELS OF SALT MARSH 2 EVOLUTION: ECOLOGICAL, GEOMORPHIC, 3 AND CLIMATIC FACTORS 4 2011. 8 [1] Salt marshes are delicate landforms at the boundary 9 between the sea and land that 13 quantify the formation and evolution of salt marshes under 14 different physical and ecological

40

Tidal regime, salinity and salt marsh plant zonation  

Microsoft Academic Search

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

Sonia Silvestri; Andrea Defina; Marco Marani

2004-01-01

41

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...

42

Vegetable Oil Spills On Salt Marshes  

Microsoft Academic Search

Following the wreck of the M.V. Kimya during which 1500 tonnes of sunflower oil was spilled, sandy sediments bound together with sunflower oil were discovered on the beach. These are still present 2½ years later. Sunflower and linseed oil were applied to salt marsh sediments to reproduce potential spills. Cores were taken and the vertical migration and degradation rates determined.

Stephen M. Mudge; Ian D. Goodchild; Matthew Wheeler

1995-01-01

43

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. 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

44

Coastal salt marshes as global methyl halide sources from determinations of intrinsic production by marsh plants  

E-print Network

Coastal salt marshes as global methyl halide sources from determinations of intrinsic production by marsh plants Steven L. Manley,1 Nun-Yii Wang,2 Maggie L. Walser,3 and Ralph J. Cicerone2,4,5 Received 23 from monospecific stands of four dominant southern California coastal salt marsh plants

Manley, Steven L.

45

Geomorphic structure of tidal hydrodynamics in salt marsh creeks  

E-print Network

Geomorphic structure of tidal hydrodynamics in salt marsh creeks Sergio Fagherazzi,1 Muriel Hannion the hydrodynamics of tidal watersheds to the geomorphic structure of salt marshes and, specifically, to the distance traveled by water particles within the channel network and on the marsh surface. The possibility

Fagherazzi, Sergio

46

Hydrocarbon degradation potential of salt marsh plant-microorganisms associations.  

PubMed

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

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

2011-07-01

47

Response of a salt marsh microbial community to metal contamination  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

48

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

EPA Science Inventory

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

49

Remote sensing of wetland conditions in West Coast salt marshes  

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

50

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

51

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...

52

Impacts of Multiple Stressors on Southern New England Salt Marshes  

EPA Science Inventory

In the Northeastern U.S., salt marsh area is in decline. Low sediment supply combined with regionally high rates of sea level rise mean that future salt marsh survival depends primarily on biomass production and organic matter accumulation, which are impacted by high nutrient lo...

53

Methylmercury production in a Chesapeake Bay salt marsh  

Microsoft Academic Search

In a detailed study of the biogeochemical factors affecting the methylation of mercury in a Chesapeake Bay salt marsh, we examined relationships between mercury methylation and numerous variables, including sulfate reduction rates, organic carbon mineralization rates, iron and sulfur chemistry, and the character of dissolved organic matter (DOM). Our data show that salt marshes are important sites of de novo

Carl P. J. Mitchell; Cynthia C. Gilmour

2008-01-01

54

Anthropogenic modification of New England salt marsh landscapes  

E-print Network

Anthropogenic modification of New England salt marsh landscapes Mark D. Bertness*, Patrick J, Providence, RI 02912 Edited by Stephen R. Carpenter, University of Wisconsin, Madison, WI, and approved October 26, 2001 (received for review August 22, 2001) Salt marshes play a critical role in the ecology

Bertness, Mark D.

55

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.

2014-11-01

56

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

57

A HIGH-RESOLUTION NUMERICAL MODEL INVESTIGATION INTO THE RESPONSE OF A CHANNELIZED SALT MARSH  

E-print Network

A HIGH-RESOLUTION NUMERICAL MODEL INVESTIGATION INTO THE RESPONSE OF A CHANNELIZED SALT MARSH of Marsh . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Site Selection VALIDATION FOR A DELAWARE BAY SALT MARSH 41 4.1 Introduction

Kirby, James T.

58

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...

59

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...

60

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

PubMed

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

Guo, Hongyu; Pennings, Steven C

2012-11-01

61

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

62

Development of Salt Marsh Monitoring Methodology Using Remote Sensing and GIS  

E-print Network

Development of Salt Marsh Monitoring Methodology Using Remote Sensing and GIS Y.Q. Wang, PI://www.ltrs.uri.edu #12;New Satellite Data in Salt Marsh Change Monitoring Given that salt marsh monitoring requires update the salt marsh maps are necessary. Recent development of high spatial resolution satellite remote

Wang, Y.Q. "Yeqiao"

63

Methane flux from coastal salt marshes  

NASA Technical Reports Server (NTRS)

It is thought that biological methanogenesis in natural and agricultural wetlands and enteric fermentation in animals are the dominant sources of global tropospheric methane. It is pointed out that the anaerobic soils and sediments, where methanogenesis occurs, predominate in coastal marine wetlands. Coastal marine wetlands are generally believed to be approximately equal in area to freshwater wetlands. For this reason, coastal marine wetlands may be a globally significant source of atmospheric methane. The present investigation is concerned with the results of a study of direct measurements of methane fluxes to the atmosphere from salt marsh soils and of indirect determinations of fluxes from tidal creek waters. In addition, measurements of methane distributions in coastal marine wetland sediments and water are presented. The results of the investigation suggest that marine wetlands provide only a minor contribution to atmospheric methane on a global scale.

Bartlett, K. B.; Harriss, R. C.; Sebacher, D. I.

1985-01-01

64

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

Microsoft Academic Search

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

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

2011-01-01

65

Salt marsh Claviceps purpurea in native and invaded Spartina marshes in Northern California  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fungal pathogen Claviceps purpurea (subgroup G3) has a worldwide distribution on salt marsh Spartina species. In Northern California (US), native S. foliosa sustains high rates of infection by G3 C. purpurea in marshes north of the San Francisco Estuary. Invasive populations of S. alterniflora a...

66

Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States  

USGS Publications Warehouse

We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970–2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh–mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services.

Osland, Michael J.; Day, Richard H.; Doyle, Thomas W.; Enwright, Nicholas

2013-01-01

67

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. PMID:22438851

Lovell, Charles R.; Davis, Debra A.

2012-01-01

68

Marine Micropaleontology 33 (1998) 175-202 foraminifera and total populations in salt marsh peat cores  

E-print Network

in salt marsh peat cores: Kelsey Marsh (Clinton, CT) and the Great Marshes (Barnstable, MA) H. Saffert 1997 Abstract Common species of intertidal agglutinated benthic foraminifera in salt marshes in Massachusetts and Connecticut live predominantly at the marsh surface and in the topmost sediment (O-2.5 cm

Royer, Dana

69

The impact of grazing on plant communities, plant populations and soil conditions on salt marshes  

Microsoft Academic Search

Grazing an abandoned salt marsh causes retrogressive succession, since mid salt-marsh communities change into lower salt-marsh communities. Grazing and mowing are compared in detail. Both management practices enhance species diversity in an abandoned salt marsh. This can be attributed to the removal of litter. The finding that lower salt-marsh species appear more with grazing than with mowing or abandoning is

J. P. Bakker

1985-01-01

70

Effects of crab burrows on pore water flows in salt marshes  

NASA Astrophysics Data System (ADS)

Macro-pores such as crab burrows are found commonly distributed in salt marsh sediments. Their disturbance on the soil structure is likely to influence both pore water flows and solute transport in salt marshes; however, the effects of crab burrows are not well understood. Here, a three-dimensional model simulated tidally driven pore water flows subject to the influence of crab burrows in a marsh system. The model, based on Richards' equation, considered variably saturated flow in the marsh with a two-layer soil configuration, as observed at the Chongming Dongtan wetland (Shanghai, China). The simulation results showed that crab burrows distributed in the upper low-permeability soil layer, acting as preferential flow paths, affected pore water flows in the marsh particularly when the contrast of hydraulic conductivity between the lower high-permeability soil layer and the overlying low-permeability soils was high. The burrows were found to increase the volume of tidally driven water exchange between the marsh soil and the tidal creek. The simulations also showed improvement of soil aeration conditions in the presence of crab burrows. These effects may lead to increased productivity of the marsh ecosystem and enhancement of its material exchange with coastal waters.

Xin, Pei; Jin, Guangqiu; Li, Ling; Barry, D. A.

2009-03-01

71

PRODUCTION IN COASTAL SALT MARSHES OF SOUTHERN CALIFORNIA  

EPA Science Inventory

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

72

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. PMID:22733752

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

2012-01-01

73

A Comparison of Salt Marsh Construction Costs with the Value of Exported Shrimp Production  

E-print Network

ARTICLE A Comparison of Salt Marsh Construction Costs with the Value of Exported Shrimp Production to coastal salt marshes. Continuing wetland loss in Galveston Bay, Texas (USA) has led to the development of various salt marsh restoration projects. These constructed wetlands often attempt to mimic natural marsh

74

Primary Research Paper Ecosystem response to changes in water level of Lake Ontario marshes: lessons  

E-print Network

Primary Research Paper Ecosystem response to changes in water level of Lake Ontario marshes, Great Lake, Lake Ontario, emergent vegetation, submersed aquatic vegetation, coastal wetland Abstract Paradise Marsh (L. Ontario) to reduce sediment resuspension and bioturbation, and thus regenerate marsh

McMaster University

75

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

USGS Publications Warehouse

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

Dudley, Robert W.; Nielsen, Martha G.

2011-01-01

76

Comparative Geomorphology of Salt and Tidal Freshwater Marsh Environments  

NASA Astrophysics Data System (ADS)

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

Pasternack, G. B.

2002-05-01

77

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

Microsoft Academic Search

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

Scott W. Shumway; Mark D. Bertness

1992-01-01

78

Living foraminifera and total populations in salt marsh peat cores: Kelsey Marsh (Clinton, CT) and the Great Marshes (Barnstable, MA)  

Microsoft Academic Search

Common species of intertidal agglutinated benthic foraminifera in salt marshes in Massachusetts and Connecticut live predominantly at the marsh surface and in the topmost sediment (0–2.5 cm), but a considerable part of the fauna lives at depths of 2.5–15 cm. Few specimens are alive at depths of 15–25 cm, with rare individuals alive between 25–50 cm in the sediments. Specimens

H. Saffert; E. Thomas

1998-01-01

79

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

80

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. PMID:24651837

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

2014-01-01

81

Salt Marsh Harvest Mouse (Reithrodontomys Raviventris)  

USGS Multimedia Gallery

San Francisco Bay — which has already lost the majority of its marsh habitat since the 19th Century — could lose even more marshes by the year 2100 due to sea level rise, according to a new USGS report. Animations, graphs and data from the USGS Open File Report 2013-1081 and th...

82

Impact of sheep grazing on juvenile sea bass, Dicentrarchus labrax L., in tidal salt marshes  

E-print Network

Impact of sheep grazing on juvenile sea bass, Dicentrarchus labrax L., in tidal salt marshes P L., from sheep grazed and ungrazed tidal salt marshes were com- pared qualitatively. Juvenile sea bass colonise the salt marsh at ¯ood during 43% of the spring tides which inundate the salt

Paris-Sud XI, Université de

83

Salt marsh vegetation change in response to tidal restriction  

Microsoft Academic Search

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

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

1984-01-01

84

Making and Measuring a Model of a Salt Marsh  

ERIC Educational Resources Information Center

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

Fogleman, Tara; Curran, Mary Carla

2007-01-01

85

Geographic Variability in Salt Marsh Flooding Patterns may Affect Nursery Value for Fishery Species  

E-print Network

Geographic Variability in Salt Marsh Flooding Patterns may Affect Nursery Value for Fishery Species (outside the USA) 2011 Abstract Flooding of salt marshes controls access to the marsh surface for aquatic geographic variability in marsh access by measuring tidal flooding characteristics in 15 Spartina

86

The role of denitrification in the nitrogen cycle of New England salt marshes  

E-print Network

I used direct measurements of nitrogen gas (N? fluxes and a ¹?N stable isotope tracer to determine the contribution of denitrification to salt marsh sediment N cycling. Denitrification in salt marsh tidal creekbottoms is ...

Hamersley, Michael Robert

2002-01-01

87

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...

88

Does vegetation prevent wave erosion of salt marsh edges?  

PubMed Central

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves. PMID:19509340

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

2009-01-01

89

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

90

Mangrove expansion and salt marsh decline at mangrove poleward limits.  

PubMed

Mangroves are species of halophytic intertidal trees and shrubs derived from tropical genera and are likely delimited in latitudinal range by varying sensitivity to cold. There is now sufficient evidence that mangrove species have proliferated at or near their poleward limits on at least five continents over the past half century, at the expense of salt marsh. Avicennia is the most cold-tolerant genus worldwide, and is the subject of most of the observed changes. Avicennia germinans has extended in range along the USA Atlantic coast and expanded into salt marsh as a consequence of lower frost frequency and intensity in the southern USA. The genus has also expanded into salt marsh at its southern limit in Peru, and on the Pacific coast of Mexico. Mangroves of several species have expanded in extent and replaced salt marsh where protected within mangrove reserves in Guangdong Province, China. In south-eastern Australia, the expansion of Avicennia marina into salt marshes is now well documented, and Rhizophora stylosa has extended its range southward, while showing strong population growth within estuaries along its southern limits in northern New South Wales. Avicennia marina has extended its range southwards in South Africa. The changes are consistent with the poleward extension of temperature thresholds coincident with sea-level rise, although the specific mechanism of range extension might be complicated by limitations on dispersal or other factors. The shift from salt marsh to mangrove dominance on subtropical and temperate shorelines has important implications for ecological structure, function, and global change adaptation. PMID:23907934

Saintilan, Neil; Wilson, Nicholas C; Rogers, Kerrylee; Rajkaran, Anusha; Krauss, Ken W

2014-01-01

91

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

92

ASSESSING HABITAT SELECTION BY FORAGING EGRETS IN SALT MARSHES AT MULTIPLE SPATIAL SCALES  

Microsoft Academic Search

We assessed salt marsh use by foraging egrets in coastal Rhode Island, USA. Two species (great egret (Ardea alba) and snowy egret (Egretta thula)) nest in mixed-species colonies on islands in Narragansett Bay and regularly forage in adjacent salt marshes. We surveyed 13 salt marshes approximately twice weekly during the breeding and post-breeding seasons in 2001 and 2002. Based on

Carol Lynn Trocki; Peter W. C. Paton

2006-01-01

93

Habitat selection of wintering passerines in salt marshes of the German Wadden Sea  

Microsoft Academic Search

The salt marshes of the Wadden Sea are important wintering areas for some species of granivorous passerines, which have declined considerably since the 1960s. We investigated the habitat choice of all wintering passerines in eight study areas in German salt marshes with special consideration of human impact on these habitats. Granivorous species that almost exclusively winter in salt marshes, Shorelark

Jochen Dierschke; Franz Bairlein

2004-01-01

94

Abstract We explored the generality of the processes mediating shrub zonation in western Atlantic salt marsh-  

E-print Network

salt marsh- es by comparing the results of our experiments in Geor- gia, USA with previous studies from salt marshes. Within the shrub zone, physical stress increased at lower elevations, shrubs at lower gerardi in Rhode Island salt marshes. However, markedly different processes appear to occur further

Pennings, Steven C.

95

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

E-print Network

intertidal habitats such as salt marsh. Following the BP Deepwater Horizon oil spill, we sampled and Recovery of Salt Marsh Arthropod Communities following BP Deepwater Horizon Oil Spill. PLoS ONE 7(3): eDisturbance and Recovery of Salt Marsh Arthropod Communities following BP Deepwater Horizon Oil

Pennings, Steven C.

96

Nekton of New Seagrass Habitats Colonizing a Subsided Salt Marsh in Galveston Bay, Texas  

E-print Network

Delwood Beach Road, Panama City, Florida 32408 ABSTRACT: Subsidence and erosion of intertidal salt marshNekton of New Seagrass Habitats Colonizing a Subsided Salt Marsh in Galveston Bay, Texas SETH P species and their forage. Salt marshes and seagrasses are particularly important in main- taining

97

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

Microsoft Academic Search

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

Theresa A. Theodose; Janette Martin

2003-01-01

98

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...

99

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

USGS Publications Warehouse

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

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

2002-01-01

100

Effects of regular salt marsh haying on marsh plants, algae, invertebrates and birds at Plum Island Sound, Massachusetts  

Microsoft Academic Search

The haying of salt marshes, a traditional activity since colonial times in New England, still occurs in about 400 ha of marsh\\u000a in the Plum Island Sound estuary in northeastern Massachusetts. We took advantage of this haying activity to investigate how\\u000a the periodic large-scale removal of aboveground biomass affects a number of marsh processes. Hayed marshes were no different\\u000a from adjacent

Robert N. Buchsbaum; Linda A. Deegan; Julie Horowitz; Robert H. Garritt; Anne E. Giblin; John P. Ludlam; David H. Shull

2009-01-01

101

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...

102

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

103

Sedimentation rates in flow-restricted and restored salt marshes in Long Island Sound  

Microsoft Academic Search

Many salt marshes in densely populated areas have been subjected to a reduction in tidal flow. In order to assess the impact\\u000a of tidal flow restriction on marsh sedimentation processes, sediment cores were collected from flow-restricted restricted\\u000a salt marshes along the Connecticut coast of Long Island Sound. Cores were also collected from unrestricted reference marshes\\u000a and from a marsh that

Shimon C. Anisfeld; Marcia J. Tobin; Gaboury Benoit

1999-01-01

104

Hydrological controls on methylmercury flux from an intertidal salt marsh  

NASA Astrophysics Data System (ADS)

We analyzed surface water and groundwater controls on dissolved methylmercury (MeHg) flux from a San Francisco Estuary salt marsh using a combination of field measurements, geochemical analyses, and numerical modeling. Tidal stage and water chemistry were continuously measured in a marsh tidal channel over two tidal cycles in January and September 2011, and sediment and pore water samples were collected from the marsh plain. Analyses included dissolved MeHg, DOC, dissolved trace metals and inorganic water chemistry, and total dry sediment mercury (THg). Net MeHg flux was estimated using volumetric flux obtained from a 3D numerical model of the marsh accounting for surface water and groundwater dynamics. Field data and simulation results suggest that spatial and temporal variability are controlled by interacting hydrological and biogeochemical processes related to historical conditions and tides. Marsh pore water and sediments in the top 45 cm were high in Hg, consistent with historical mining in the region (mean MeHg 2.25 +/-1.41 ng/L, THg(s) 1.14 +/-0.36 ug/g). During low tide, when marsh groundwater seepage was the dominant water source, MeHg concentrations in the surface water were high (mean MeHg 0.70 +/-0.40 ng/L), DOC concentrations were low, and DOC aromaticity was high (indicating terrestrial sources). These patterns were reversed during high tide (mean MeHg 0.16 +/-0.08 ng/L), when the channels were filled with bay water. MeHg was not strongly correlated with THg in surface water, pore water, or sediments, suggesting THg availability is not a strong control on MeHg production within the marsh. Simulation results suggest that surface water-groundwater exchange, including dissolved MeHg seepage, is controlled hydrologically by: channel bank topography, marsh surface depressions, and marsh surface water balance as influenced by evapotranspiration.

Zhang, H.; Moffett, K. B.; Windham-Myers, L.; Gorelick, S.

2013-12-01

105

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

PubMed

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

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

2009-09-01

106

Nitrogen Cycling and Ecosystem Exchanges in a Virginia Tidal Freshwater Marsh  

E-print Network

Nitrogen Cycling and Ecosystem Exchanges in a Virginia Tidal Freshwater Marsh SCOTT C. NEUBAUER1 of Biology, Villanova, Pennsylvania 19085 ABSTRACT: Tidal freshwater marshes are diverse habitats that differ both within and between marshes in terms of plant community composition, sediment type, marsh elevation

Neubauer, Scott C.

107

Biogeomorphically driven salt pan formation in Sarcocornia-dominated salt-marshes  

NASA Astrophysics Data System (ADS)

Salt-marshes are under increasing threat, particularly from sea-level rise and increased wave action associated with climate change. The development and stability of these valuable habitats largely depend on complex interactions between biotic and abiotic processes operating at different scales. Also, interactions between biotic and abiotic processes drive internal morphological change in salt-marshes. In this paper we used a biogeomorphological approach to assess the impact of biological activities and interactions on salt pan formation in Sarcocornia-dominated salt marshes. Salt pans represent a key physiographic feature of salt-marshes and recent studies hypothesized that biogeomorphic processes could be related to salt pan formation in SW Atlantic salt-marshes. The glasswort Sarcocornia perennis is one of the dominant plants in the salt-marshes of the Bahía Blanca Estuary (Argentina) where they form patches up to 8 m in diameter. These salt-marshes are also inhabited in great densities by the burrowing crab Neohelice (Chasmagnathus) granulata whose bioturbation rates are among the highest reported for salt-marshes worldwide. A set of biological interactions between N. granulata and S. perennis appears to be responsible for salt pan development in these areas which has not been described elsewhere. The main objective of this work was to determine the ecological interactions occurring between plants and crabs that lead to salt pan formation by using field-based sampling and manipulative experiments. Our results showed that S. perennis facilitated crab colonization of the salt-marsh by buffering otherwise stressful physical conditions (e.g., temperature, desiccation). Crabs preferred to construct burrows underneath plants and, once they reach high densities (up to 40 burrows m- 2), the sediment reworking caused plant die-off in the central area of patches. At this state, the patches lose elevation and become depressed due to the continuous bioturbation by crabs. Thus, salt pans are generated in this case by a set of biogeomorphic processes that include pure ecological interactions such as plant facilitation of crab settlement and also indirect negative effects of crabs on plant survival. Furthermore, crab bioturbation affects sediment structure due to concentration of burrowing activity under plant canopies promoting elevation loss and leading, after a few years, to salt pan formation in a previously vegetated substrate.

Escapa, Mauricio; Perillo, Gerardo M. E.; Iribarne, Oscar

2015-01-01

108

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

EPA Science Inventory

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

109

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

EPA Science Inventory

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

110

Results of Total Mercury Analysis in Salt Marsh Invertebrates  

EPA Science Inventory

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

111

Characterization of marine debris in North Carolina salt marshes  

Microsoft Academic Search

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

Shay Viehman; Jenny L. Vander Pluym; Jennifer Schellinger

112

New model describes toppling of salt marsh banks  

NASA Astrophysics Data System (ADS)

Salt marshes are coastal habitats that store important nutrients and serve as shelter for many estuarial species. These habitats are threatened by rising seas and human expansion, so it has become increasingly important to improve models of how these habitats degrade.

Wendel, JoAnna

2014-05-01

113

Population biology of salt marsh and sand dune annuals  

Microsoft Academic Search

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

A. R. Watkinson; A. J. Davy

1985-01-01

114

Diversity, composition, and geographical distribution of microbial communities in California salt marsh sediments  

USGS Publications Warehouse

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes. Copyright ?? 2006, American Society for Microbiology. All Rights Reserved.

Cordova-Kreylos, A. L.; Cao, Y.; Green, P.G.; Hwang, H.-M.; Kuivila, K.M.; LaMontagne, M.G.; Van De Werfhorst, L. C.; Holden, P.A.; Scow, K.M.

2006-01-01

115

Diversity, Composition, and Geographical Distribution of Microbial Communities in California Salt Marsh Sediments  

PubMed Central

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes. PMID:16672478

Córdova-Kreylos, Ana Lucía; Cao, Yiping; Green, Peter G.; Hwang, Hyun-Min; Kuivila, Kathryn M.; LaMontagne, Michael G.; Van De Werfhorst, Laurie C.; Holden, Patricia A.; Scow, Kate M.

2006-01-01

116

Effects of open marsh water management on numbers of larval salt marsh mosquitoes  

USGS Publications Warehouse

Open marsh water management (OMWM) is a commonly used approach to manage salt marsh mosquitoes than can obviate the need for pesticide application and at the same time, partially restore natural functions of grid-ditched marshes. OMWM includes a variety of hydrologic manipulations, often tailored to the specific conditions on individual marshes, so the overall effectiveness of this approach is difficult to assess. Here, we report the results of controlled field trials to assess the effects of two approaches to OMWM on larval mosquito production at National Wildlife Refuges (NWR). A traditional OMWM approach, using pond construction and radial ditches was used at Edwin B. Forsythe NWR in New Jersey, and a ditch-plugging approach was used at Parker River NWR in Massachusetts. Mosquito larvae were sampled from randomly placed stations on paired treatment and control marshes at each refuge. The proportion of sampling stations that were wet declined after OMWM at the Forsythe site, but not at the Parker River site. The proportion of samples with larvae present and mean larval densities, declined significantly at the treatment sites on both refuges relative to the control marshes. Percentage of control for the 2 yr posttreatment, compared with the 2 yr pretreatment, was >90% at both treatment sites.

James-Pirri, Mary-Jane; Ginsberg, Howard S.; Erwin, R. Michael; Taylor, Janith

2009-01-01

117

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...

118

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

PubMed

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

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

2011-02-01

119

Differential responses of tidal marsh area and delivery of ecosystem services to rising sea level  

E-print Network

Differential responses of tidal marsh area and delivery of ecosystem services to rising sea level, and coastal wetlands, tidal marshes and mangroves provide ecosystem services that benefit these coastal level will lead to a decline in tidal marsh area along the southeastern U.S. (Georgia) coast

Cai, Wei-Jun

120

The ebb and flood of Silica: Quantifying dissolved and biogenic silica fluxes from a temperate salt marsh  

NASA Astrophysics Data System (ADS)

Salt marshes are widely studied due to the broad range of ecosystem services they provide including serving as crucial wildlife habitat and as hotspots for biogeochemical cycling. Nutrients such as nitrogen (N), phosphorus (P), and carbon (C) are well studied in these systems. However, salt marshes may also be important environments for the cycling of another key nutrient, silica (Si). Found at the land-sea interface, these systems are silica replete with large stocks in plant biomass, sediments, and porewater, and therefore, have the potential to play a substantial role in the transformation and export of silica to coastal waters. In an effort to better understand this role, we measured the fluxes of dissolved (DSi) and biogenic (BSi) silica into and out of two tidal creeks in a temperate, North American (Rowley, Massachusetts, USA) salt marsh. One of the creeks has been fertilized from May to September for six years allowing us to examine the impacts of nutrient addition on silica dynamics within the marsh. High-resolution sampling in July 2010 showed no significant differences in Si concentrations between the fertilized and reference creeks with dissolved silica ranging from 0.5 to 108 ?M and biogenic from 2.0 to 56 ?M. Net fluxes indicated that the marsh is a point source of dissolved silica to the estuary in the summer with a net flux of approximately 169 mol h -1, demonstrating that this system exports DSi on the same magnitude as some nearby, mid-sized rivers. If these findings hold true for all salt marshes, then these already valuable regions are contributing yet another ecosystem service that has been previously overlooked; by exporting DSi to coastal receiving waters, salt marshes are actively providing this important nutrient for coastal primary productivity.

Vieillard, Amanda M.; Fulweiler, Robinson W.; Hughes, Zoe J.; Carey, Joanna C.

2011-12-01

121

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...

122

SELECTION OF VEGETATED HABITAT BY BROWN SHRIMp, PENAEUS AZTECUS, IN A GALVESTON BAY SALT MARSH  

E-print Network

SELECTION OF VEGETATED HABITAT BY BROWN SHRIMp, PENAEUS AZTECUS, IN A GALVESTON BAY SALT MARSH Ro. Penaeu8 aztecu8. in vegetated and nonvegetated habitats ofa Galveston West Bay salt marsh were compared and less apparent attraction to vegetation in the outer bayside part ofthe marsh to that ofhighest numbers

123

Long-Term Retention and Loss of Heavy Metals from Experimental Salt Marsh Plots  

E-print Network

Long-Term Retention and Loss of Heavy Metals from Experimental Salt Marsh Plots Katie Harrold Sippewissett Marsh I have tested the long-term retention of heavy metals by the marsh. Beginning in the early of fertilization. This could be due to sorbtion to organic matter and metal-oxides. Key Words: heavy metals, salt

Vallino, Joseph J.

124

Effects of livestock species and stocking density on accretion rates in grazed salt marshes  

NASA Astrophysics Data System (ADS)

Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management decisions of salt marshes. In our study accretion rates were higher than the current SLR. Further research is needed to include grazing effects into sedimentation models, given the importance of grazing management in the Wadden Sea area.

Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

2015-01-01

125

Algal productivity in salt marshes of Georgia  

Microsoft Academic Search

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

1959-01-01

126

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

127

Modeling the Retreat Processes of Salt Marsh Edge  

NASA Astrophysics Data System (ADS)

Edge erosion of salt marshes due to surface waves and tide forcing is likely the chief mechanism that models marsh boundaries and by which salt marshes in worldwide coastal areas are being lost. In order to address this problem, experimental observations in a laboratory flume and field measurements in the lagoon of Venice were conducted to understand the main processes controlling marsh edge retreat, with a focus on the erosion mechanisms caused by the action of wind and tidal waves. A physical model reproducing a salt marsh bank was built inside a long wave current flume where random surface waves were generated according to a given wave spectrum. The physical model was constructed with the original soil and plants taken in a marsh of the lagoon of Venice, while the wave climate was reproduced according to field measurements. The experiments were conducted in the case of both unvegetated and vegetated bank: a first set of experiments was carried out considering only tidal wave; in the second, bank models experienced the effect of wind waves superimposed to the tide. The following data were collected during the experiments: wave climate interacting with the bank, flow velocity measurements in the eroded quasi-equilibrium configuration, pressure distribution along bank edge and internal pressure fluctuation and damping due to wave impact. Bank geometry profile and bottom topography at different times have also been collected to characterize the erosion rate with time and the evolution of bank retreat. Subsequent to laboratory activity wave climate was measured close to a marsh edge in the Lagoon of Venice with the aim at identifying wave forcing on the bank surface during a moderate wind event and comparing results with the wave stress experienced by bank models in laboratory tests. Several pressure transducers installed close to the bed were used to collect wave height and wave direction with respect to the edge of the marsh. Laboratory data and field measurement were analyzed and interpreted in order to develop a simple preliminary model describing the retreat processes of a bank edge subjected to wave attack and tidal forcing. The model applies to cohesive banks determining their temporal evolution under specific boundary and initial conditions. It takes into account processes induced by hydrodynamic forcing such as particle by particle erosion and mass failure triggered by the presence of tension cracks, whereas long time scale processes such as deposition and compaction are not considered.

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

2012-12-01

128

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

129

Salt Marsh Formation in the Lower Hudson River Estuary  

NASA Technical Reports Server (NTRS)

Salt marshes are constant depositional environments and as a result contain accurate indicators of past relative sea level rise and salinity. The Hudson River marshes are at least twice as deep when compared to coastal marshes on either side of the mouth of the Hudson. The reason for this difference in sedimentation is unclear. This study uses macrofossil data as well as sediment stratigraphy in order to understand the formation and evolution of these marshes. The composition of seeds, roots, shoots and foraminifera, are used to indicate past sea levels. The four sites involved in this study are, from south to north, the Arthur Kill Marsh in Staten Island (40 36 N, 74 77W), Piermont marsh (N 4100; 73 55W) Croton Point (41 14 N; 73 50W) and Iona Island (41 18N, 73 58W). These are all tidally influenced but with increasing distances from the New York Bight, which gives a good spectrum of tidal influence. AMS-C14 dates on basal macrofossils will document the time of each marsh formation. Basal material from Arthur Kill (8 m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10 m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77 m) is lacking any identifiable macrofossils between 150 and 500 microns. The basal material from Iona Island (10 m) has vegetation such as Scirpus and Cyperus seeds, probably implying a brackish environment. The freshwater origin of the Arthur Kill marsh in Staten Island is significant because it predates either sea level rise or the western channel incision. Additional implications for this study include evidence for changes in river channel geomorphology. Reasons for the relatively deeper river marshes include possible basal clay compaction, high production due to river and marine nutrients as well as tectonic activity. This study provides the groundwork for more high-resolution studies of these marshes to understand the fluctuations in salinity caused by relative sea level rise, tectonic faulting and/or changes in precipitation/evaporation.

Merley, Michael; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

2001-01-01

130

Biogeochemical effects of seawater restoration to diked salt marshes  

USGS Publications Warehouse

We conducted greenhouse microcosm experiments to examine the biogeochemical effects of restoring seawater to historically diked Cape Cod salt marshes. Peat cores from both seasonally flooded and drained diked marshes were waterlogged with seawater, and porewater chemistry was subsequently monitored for 21 mo. The addition of seawater to highly organic, seasonally flooded peat caused the death of freshwater wetland plants, 6-8 cm of sediment subsidence, and increased N and P mineralization. Also, sulfides and alkalinity increased 10-fold, suggesting accelerated decomposition by sulfate reduction. Addition of seawater to the low-organic-content acidic peat from the drained marsh increased porewater pH, alkalinity, PO4-P, and Fe(II), which we attribute to the reestablishment of SO4 and Fe(III) mineral reduction. Increased cation exchange contributed to 6-fold increases in dissolved Fe(II) and Al and 60-fold increases in NH4-N within 6 mo of sail-nation. Seawater reintroductions to seasonally flooded diked marshes will cause porewater sulfides to increase, likely reducing the success of revegetation efforts. Sulfide toxicity is of less concern in resalinated drained peats because of the abundance of Fe(II) to precipitate sulfides, and of NH4-N to offset sulfide inhibition of N uptake. Restoration of either seasonally flooded or drained diked marshes could stimulate potentially large nutrient and Fe(II) releases, which could in turn increase primary production and lower oxygen in receiving waters. These findings suggest that tidal restoration be gradual and carefully monitored.

Portnoy, J.W.; Giblin, A.E.

1997-01-01

131

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

132

Spatial variations of carbon, nitrogen, phosphorous and sulfur in the salt marsh sediments of the Yangtze Estuary in China  

NASA Astrophysics Data System (ADS)

Surface sediments and three sediment vibrocores were collected from the salt marsh of the Yangtze Estuary in order to examine the C, N, P and S distributions. Marsh plants and suspended particulate matter (SPM) from the river were also sampled and analyzed in order to determine their elemental compositions. The levels of total organic carbon (0.1-0.7%) and C/N ratios (6-11) in the surface sediments of the Yangtze Estuary salt marsh were relatively low compared with those reported for other salt marshes in European and North American coastal areas. The total organic carbon (TOC) level and C/N ratio of the surface sediments were similar to those of the SPM in the Yangtze Estuary, but were much lower than those of the marsh plant samples. These findings support the view that organic matter in the surface sediments is largely derived from SPM in the river, with minor contributions from the marsh vegetation. Total phosphorus (TP) showed irregular variation in its spatial distribution, whereas the TOC, total nitrogen (TN) and total sulfur (TS) concentrations were highest in the high marsh zones and lowest in the bare flat areas. This pattern was related to the spatial variability of the sediment grain size (i.e. clay-rich sediments in the high marsh zones resulted in elevated TOC, TN and TS contents). Some vibrocore sediments in the mid-depths of the high and low marsh zones, however, showed greater TOC contents than might have been predicted from the TOC-grain size relationship. This suggested the existence of additional organic inputs (i.e. marsh vegetation) for these vibrocore sediment sections, despite their original riverine source. After eliminating the effect of grain size, it was calculated that 22-55% of the TOC and 0.6-35% of the TN in the sediment samples were derived from the marsh vegetation. Considering both the vertical accretion rate and the ecosystem evolution of the salt marsh, it was estimated that the annual contributions of TOC and TN made by the marsh vegetation to the sediments in the Yangtze Estuary were 5.8 × 10 11 g C yr -1 and 2.3 × 10 10 g N yr -1, respectively, with corresponding accumulation rates of 1.1-1.5 × 10 10 g C yr -1 and 4.4-5.8 × 10 8 g N yr -1 at the present time.

Zhou, Junli; Wu, Ying; Kang, Qinshu; Zhang, Jing

2007-01-01

133

Suitability of different salt marsh plants for petroleum hydrocarbons remediation  

Microsoft Academic Search

The suitability of the salt-marsh species Halimione portulacoides, Scirpus maritimus, Juncus maritimus and an association of the last two for remediation of petroleum hydrocarbons (PHC) in soil was investigated. An outdoor laboratory experiment (microcosm-scale) was carried out using contaminated soil collected in a refinery, as a complement of another study carried out in the refinery environment (mesocosm-scale). Soil samples with

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

2011-01-01

134

Nutrient limitation and plant species composition in temperate salt marshes  

Microsoft Academic Search

Addition of inorganic nitrogen, phosphorus and potassium in a factorial design in two ungrazed Wadden-Sea salt marshes at\\u000a low and high elevations showed that nitrogen was the limiting nutrient. No effects of nutrient addition were detected in the\\u000a 1st year, probably due to a considerable rainfall deficit during the growing season. In the 2nd year, which was more humid,\\u000a only

K. Kiehl; P. Esselink; J. P. Bakker

1997-01-01

135

Salt-Marsh and Mudflat Ecological Patterns From Remote Sensing  

NASA Astrophysics Data System (ADS)

Coastal wetland areas, such as lagoons and estuaries, are complex and delicate environments subject to rapid morphological and ecological evolution, often in response to strong anthropogenic pressure. The combined ecological and economic importance of these dynamic environments has focused attention on monitoring and forecasting change in these natural coastal deposits. Salt marshes and mudflats in tidal environments are characterised by complex spatial patterns of form, both in their geomorphological and ecological features. Spatial patterns of microbial and vegetation assemblage distribution and composition provide essential information for describing the state of intertidal systems while any alteration in these patterns help to understand and assess system change. The present contribution describes quantitative observations of ecological (vegetation and microphytobenthos) and morphological (topography and channel network geometry) of selected systems using remote sensing and field observations performed during the European research project TIDE (Tidal Inlets Dynamics and Environment, EVK3-CT-2001-00064). The optimal observational configuration was assessed to retrieve accurate quantitative maps of salt marsh plants, macroalgae and microphytobenthos, with specific reference to the salt marshes of the Venice Lagoon (Italy) and to the mudflats of the Eden Estuary (Scotland). Statistical analyses applied on the vegetation maps obtained allowed the derivation of relationships between morphological characteristics and vegetation distribution. Finally vegetation biodiversity was quantified in space and its relationship with various topographic/geomorphic parameters (e.g. proximity to the channel network, soil elevation, etc.) was determined.

Belluco, E.; Camuffo, M.; Vardy, S.; Ferrari, S.; Feola, A.; Silvestri, S.; Paterson, D. M.; Marani, A.; Marani, M.

2005-12-01

136

Distribution and metabolism of quaternary amines in salt marshes  

NASA Technical Reports Server (NTRS)

Quaternary amines such as glycine betaine (GBT) are common osmotically active solutes in much of the marine biota. GBT is accumulated by various bacteria, algae, higher plants, invertebrates, and vertebrates in response to salinity or water stresses; in some species, GBT occurs at tens to hundreds of millimolar concentrations and can account for a significant fraction of total nitrogen. Initial studies suggest that GBT is readily converted to two potential methane precursors, trimethylamine (TMA) and acetate, in anoxic sediments. TMA is apparently the most important methane precursor in surface sediments containing sulfate reducing bacteria. In salt marshes, the bulk of the methane formed may be due to the metabolism of TMA rather than other substrates. Current research is focussed on testing this hypothesis and on determining the role of quaternary amino osmoregulatory solutes in methane fluxes from marine environments. Preliminary studies have dealt with several problems: (1) determination of GBT concentrations in the dominant flora and fauna of salt marshes; (2) synthesis of radiolabelled GBT for metabolic studies; and (3) determination of fates of BGT in marine sediments using radiotracers. Both GC and HPLC techniques have been used to assay GBT concentrations in plant and animal tissues. S. alterniflora is probably the only significant source of GBT (and indirectly of methane) since the biomass and distribution of most other species is limited. Current estimates suggest that S. alterniflora GBT could account for most of the methane efflux from salt marshes.

King, Gary M.

1985-01-01

137

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

138

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

139

Response of Salt Marsh Ponds to Eutropication Austin N. Ritter1,3  

E-print Network

Response of Salt Marsh Ponds to Eutropication Austin N. Ritter1,3 , David Dodge1 , Linda A. Deegan2 examined the response of New England salt marsh ponds to nutrient loading via flooding tidal water as part of nutrient (70 uM nitrate and 4uM phosphate). Our results indicate that gross nitrate processing in salt

Vallino, Joseph J.

140

Evaluation of white plastic flags as visual repellents for Snow Geese on coastal salt marshes  

Microsoft Academic Search

Excessive grazing by Snow Geese (Chen caerulescens) causes severe damage to salt marshes along the eastern seaboard of the United States and to traditional agricultural practices such as salt hay farming. The effectiveness of white plastic flags as visual repellents to Snow Geese (Chen caerulescens) on six Delaware Bay salt hay (Spartina sp.) marshes was evaluated. At each site, two

J. Russell Mason

1995-01-01

141

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

142

Assessing habitat selection by foraging egrets in salt marshes at multiple spatial scales  

Microsoft Academic Search

We assessed salt marsh use by foraging egrets in coastal Rhode Island, USA. Two species [great egret (Ardea alba) and snowy egret (Egretta thula)] nest in mixed-species colonies on islands in Narragansett Bay and regularly forage in adjacent salt marshes. We surveyed\\u000a 13 salt marshes approximately twice weekly during the breeding and post-breeding seasons in 2001 and 2002. Based on

Carol Lynn Trocki; Peter W. C. Paton

2006-01-01

143

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.

144

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

ERIC Educational Resources Information Center

This teaching guide deals with the ecological composition of a marsh and the ecological effects certain changes might have on a marsh. This study focuses on the fresh water marsh found in the Florida Everglades which can furnish the student with several examples of past, present, and possible future ecological changes which impact this ecosystem

Brevard County School Board, Cocoa, FL.

145

Long-term Surface Elevation Change in Salt Marshes: a Prediction of Marsh Response to Future Sea-Level Rise  

Microsoft Academic Search

Accretion rates and surface elevation changes were measured in three natural salt marshes in the Wadden Sea. Derived from these measurements, a simple predictive model was made which describes changes in surface elevation during more than 100 years of salt-marsh development at several sea-level rise scenarios. The model was tested with data on long-term surface elevation changes at several successional

H. J. van Wijnen; J. P. Bakker

2001-01-01

146

Salt Marsh as a Coastal Filter for the Oceans: Changes in Function with Experimental Increases in Nitrogen Loading and Sea-Level Rise  

PubMed Central

Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH4NO3)-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication. PMID:22879873

Nelson, Joanna L.; Zavaleta, Erika S.

2012-01-01

147

Diurnal Fluxes of Carbonyl Sulfide (COS) in a Subtropical Salt Marsh  

NASA Astrophysics Data System (ADS)

The atmospheric sulfur budget has been greatly perturbed, with anthropogenic contributions exceeding natural emissions. Carbonyl sulfide (COS) is the most abundant, longest-lived reduced sulfur compound in the atmosphere, and COS concentration changes could have a significant effect on the global climate and the natural biogeochemical sulfur cycle. Measuring fluxes of COS presents a methodological challenge, and in situ measurements from terrestrial ecosystems are sparse. Terrestrial plants are considered to be the largest sink for COS in the troposphere, although specific species have been reported to act as sources. Here we describe production rates of COS from salt marsh plants on a Texas Gulf coast subtropical barrier island (27.8 °N, 97.1°W). In July 2009, static flux chamber measurements were performed on three sites over the course of 24 hours to capture the temporal and spatial variation of fluxes. Two of the sites were dominated by B. maritima, a common salt marsh plant, while one was a control plot with only marsh soil and no vegetation. Fluxes from the two sites were measured within an hour of each other and showed a very similar pattern with time, indicating that the COS emissions responded to the same environmental factors. Of the environmental parameters measured, fluxes correlated best with soil temperatures at 5 cm depth. The site with the drier of the two soils consistently yielded a 20-30% larger flux. The control plot produced an order of magnitude less COS, but still exhibited a positive flux. These results are part of an ongoing study on how subtropical salt marshes contribute to the global atmospheric sulfur budget.

Whelan, M.; Min, D. H.; Rhew, R. C.; Liu, Y.

2009-12-01

148

Changes in salt marsh vegetation, Phragmites australis , and nekton in response to increased tidal flushing in a New England salt marsh  

Microsoft Academic Search

This study examined the response of Argilla Marsh in Ipswich, Massachusetts, USA to increased tidal flushing instituted to\\u000a restore a salt marsh invaded by Phragmites australis. In late fall 1998, we replaced the old 0.9-m-diameter culvert feeding this marsh with a 2.4 × 1.5-m box culvert, thus increasing\\u000a both the volume of tidal exchange and porewater salinity. We carried out

Robert N. Buchsbaum; John Catena; Eric Hutchins; Mary-Jane James-Pirri

2006-01-01

149

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. PMID:25009538

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

2014-01-01

150

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

Microsoft Academic Search

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

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

2009-01-01

151

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. PMID:23861964

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

2013-01-01

152

The effects of marsh edge and surface elevation on the distribution of salt marsh infauna and prey availability for nekton predators  

E-print Network

The relative importance of edge and elevation on infaunal distribution patterns within an intertidal collecting infauna on the nonvegetated intertidal and within the marsh at tina Iterniflora salt marsh was examined by distances of one, three., five...

Whaley, Shannon Diann

2012-06-07

153

Ability of salt marsh plants for TBT remediation in sediments  

Microsoft Academic Search

Introduction  The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT)\\u000a from estuarine sediments was investigated, using different experimental conditions.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The influence of H. portulacoides on degradation of the butyltin compounds was assessed in two different ways: (1) a 9-month ex situ study carried out

Pedro N. Carvalho; M. Clara P. Basto; Manuela F. G. M. Silva; Ana Machado; A. A. Bordalo; M. Teresa S. D. Vasconcelos

2010-01-01

154

Microdiversity of Culturable Diazotrophs from the Rhizoplanes of the Salt Marsh Grasses Spartina alterniflora and Juncus roemerianus  

Microsoft Academic Search

Salt marshes dominated by Spartina alterniflora (smooth cordgrass) are among the most productive ecosystems known, despite nitrogen limitation. Rhizoplane\\/rhizosphere diazotrophy\\u000a (nitrogen fixation) serves as a significant source of combined nitrogen in these systems. Several recent studies have demonstrated\\u000a remarkable physiological and phylogenetic macro- and microdiversity within this important functional group of organisms. However,\\u000a the ecological significance of this diversity is

C. E. Bagwell; C. R. Lovell

2000-01-01

155

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

156

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

Microsoft Academic Search

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

Yanina L. Idaszkin; Alejandro Bortolus

2011-01-01

157

Landscape Patterns of Forb Pannes Across a Northern New England Salt Marsh  

Microsoft Academic Search

Most salt marshes are dominated by graminoids, but patches dominated by a diverse assemblage of perennial forbs, known as\\u000a forb pannes, occur on marshes in north temperate areas. These pannes and their associated species diversity appear to be highly\\u000a responsive to anthropogenic change, including climate warming. We mapped all of the forb pannes on a salt marsh in Wells,\\u000a Maine

Pamela Jayne Griffin; Theresa Theodose; Michele Dionne

2011-01-01

158

The geochemistry of salt marshes: Sedimentary ion diffusion, sulfate reduction, and pyritization  

Microsoft Academic Search

Abstract-A series of seasonal cores was taken in a high marsh near the terminus of Delaware Bay, U.S.A. A seasonal harmonic,diffusion model was successfully fit to the concentration,profiles of chloride ion in the salt marsh,pore waters yielding a calculated sedimentary,diffusion coefficient. Virtually all other chemical,reactions within salt marsh,sediments,are directly linked to the rate and stoichiometry,of organic decomposition.,The rich organic input

C LORDIII; THOMAS M. CHURCH

1983-01-01

159

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

USGS Publications Warehouse

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

Nielsen, Martha G.; Dudley, Robert W.

2013-01-01

160

Vulnerability of Rhode Island Salt Marshes to Sea Level Rise and Poor Water Quality  

EPA Science Inventory

Across the northeastern Unites States, salt marshes are losing ground. Edges are eroding, tidal channel networks are expanding, and new ponds are forming and expanding within salt marshes. This leaves shorelines - and in some cases houses - more vulnerable to nor'easters and tr...

161

Factors Affecting Carbohydrate Production and Loss in Salt Marsh Sediments of Galveston Bay  

E-print Network

in the surface 5 mm of intertidal sediment in a subtropical salt marsh (Galveston Bay, Texas). Nitrogen and phosphorus were added to cores collected from the salt marsh and incubated in the lab over four days. Very little change was seen in the biomass...

Wilson, Carolyn E.

2010-10-12

162

THE EFFECT OF DOMINANT GRASS SPECIES ON NITROGEN CYCLING IN GREAT SIPPEWISSETT SALT MARSH SEDIMENTS  

E-print Network

THE EFFECT OF DOMINANT GRASS SPECIES ON NITROGEN CYCLING IN GREAT SIPPEWISSETT SALT MARSH SEDIMENTS ABSTRACT Salt marsh productivity and nitrogen cycling are tightly linked processes that can be affected species influence the rate of nitrogen cycling in the sediments and, in turn, the overall productivity

Vallino, Joseph J.

163

Effects of Nitrate on Decomposition in Salt Marsh Peats Arianna Goodman  

E-print Network

Effects of Nitrate on Decomposition in Salt Marsh Peats Arianna Goodman Oberlin College `13 Advisor and loss. Rapid nitrate addition to salt marshes may stimulate bacterial decomposition of existing peat, and the decomposition may contribute to creek bank destabilization and collapse. Alternately, peat deposited in high-nitrate

Vallino, Joseph J.

164

Characterization of humic substances in salt marsh soils under sea rush ( Juncus maritimus)  

Microsoft Academic Search

Humic substances (HS) from salt marsh soils were characterized and the relationships among HS composition and some geochemical factors were analysed. For this, three salt marshes with the same vegetation cover (Juncus maritimus), but with different geochemical characteristics, were selected. The qualitative characterization of the soil humic acids and fulvic acids was carried out by elemental analysis, FTIR spectroscopy, fluorescence

C. Santín; M. González-Pérez; X. L. Otero; P. Vidal-Torrado; F. Macías; M. Á. Álvarez

2008-01-01

165

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...

166

Relationships Between Watershed Emergy Flow and Coastal New England Salt Marsh Structure, Function, and Condition  

EPA Science Inventory

This study evaluated the link between watershed activities and salt marsh structure, function, and condition using spatial emergy flow density (areal empower density) in the watershed and field data from 10 tidal salt marshes in Narragansett Bay, RI. The field-collected data wer...

167

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

EPA Science Inventory

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

168

Competition and herbivory during salt marsh succession: the importance of forb growth strategy  

Microsoft Academic Search

Summary 1 Despite much debate about their importance, only a few field studies have evalu- ated the intensity of competition and herbivory. 2 Artemisia maritima, Atriplex portulacoides and Plantago maritima, three plant species which are common in European temperate salt marshes, were transplanted into diÄerent successional stages (15, 30 and 45 years old) of a temperate salt marsh. Biomass of

Carsten F. Dormann; Rene Van Der Wal; Jan P. Bakker

2000-01-01

169

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

E-print Network

Biotic interactions mediate the expansion of black mangrove (Avicennia germinans) into salt marshes of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its decades, freeze-free winters have led to an expansion of black mangrove into salt marshes. We examined how

Pennings, Steven C.

170

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

Microsoft Academic Search

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

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

2003-01-01

171

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-...

172

Effects of Nitrate Fertilization on Pyrite Oxidation in Salt Marsh Sediments Ben Pyenson1  

E-print Network

Effects of Nitrate Fertilization on Pyrite Oxidation in Salt Marsh Sediments Ben Pyenson1 Advisor;Pyenson 2 Abstract: Pyrite oxidation and NO3- loading to estuaries present unique environmental problems studied the effects of NO3- fertilization on pyrite oxidation in salt marshes with the hypothesis that NO3

Vallino, Joseph J.

173

DENITRIFICATION ENZYME ACTIVITY OF FRINGE SALT MARSHES IN NEW ENGLAND (USA)  

EPA Science Inventory

Coastal salt marshes are a buffer between the uplands and adjacent coastal waters in New England (USA). With increasing N loads from developed watersheds, salt marshes could play an important role in the water quality maintenance of coastal waters. In this study we examined seaso...

174

Suitability of different salt marsh plants for petroleum hydrocarbons remediation.  

PubMed

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

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

2011-08-01

175

Biogeochemical drivers of phosphatase activity in salt marsh sediments  

NASA Astrophysics Data System (ADS)

Although nitrogen has become a major concern for wetlands scientists dealing with eutrophication problems, phosphorous represents another key element, and consequently its biogeochemical cycling has a crucial role in eutrophication processes. Microbial communities are a central component in trophic dynamics and biogeochemical processes on coastal systems, since most of the processes in sediments are microbial-mediated due to enzymatic action, including the mineralization of organic phosphorus carried out by acid phosphatase activity. In the present work, the authors investigate the biogeochemical sediment drivers that control phosphatase activities. Authors also aim to assess biogeochemical factors' influence on the enzyme-mediated phosphorous cycling processes in salt marshes. Plant rhizosediments and bare sediments were collected and biogeochemical features, including phosphatase activities, inorganic and organic phosphorus contents, humic acids content and pH, were assessed. Acid phosphatase was found to give the highest contribution for total phosphatase activity among the three pH-isoforms present in salt marsh sediments, favored by acid pH in colonized sediments. Humic acids also appear to have an important role inhibiting phosphatase activity. A clear relation of phosphatase activity and inorganic phosphorous was also found. The data presented reinforces the role of phosphatase in phosphorous cycling.

Freitas, Joana; Duarte, Bernardo; Caçador, Isabel

2014-10-01

176

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

USGS Publications Warehouse

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

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

2003-01-01

177

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

178

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

USGS Publications Warehouse

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

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

2001-01-01

179

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

Microsoft Academic Search

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

MARK D. BERTNESS

1991-01-01

180

Impact of an invasive plant ( Elymus athericus) on the conservation value of tidal salt marshes in western France and implications for management: Responses of spider populations  

Microsoft Academic Search

As a result of Elymus athericus (Poaceae) invasion in the last 10 years, a major change in vegetation cover has occurred in salt marshes of the Mont Saint-Michel bay (France). Such invasions are known to modify biodiversity and consequently ecosystem proprieties and functions as well as the conservation value of invaded areas. In this study, we especially focus (1) on

Julien Pétillon; Frédéric Ysnel; Alain Canard; Jean-Claude Lefeuvre

2005-01-01

181

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

182

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. PMID:24904599

Carey, Joanna C.; Fulweiler, Robinson W.

2014-01-01

183

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. PMID:24917856

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

2014-01-01

184

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

SciTech Connect

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

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

1982-03-01

185

Distribution patterns of salt marsh vegetation on Parramore Island, Virginia Coast Reserve  

SciTech Connect

The Virginia Coast Reserve is a classic example of an estuarine-barrier island complex, and is dominated physiographically by tidal salt marshes. Marsh vegetation includes Spartina alterniflora and patens, Juncus romerianus, Disticlis spicata and Salicornia virginica; these species occur in a random mosaic pattern throughout the salt marsh. Previous work has shown that porewater salinity and flooding frequency control plant distributions at a gross scale (daily tidal inundation versus occasional flooding), but variations in these parameters are extremely subtle in the Parramore marshes. The goal of this research is to document and monitor small-scale physical factors that control spatial distribution of marsh species. The results of this study have serious implications for development of artificial wetlands. Topographic variations on the order of < 10 cm are significant in determining both flooding history and water table salinity, and therefore affect the colonization and growth of marsh plant species dramatically.

Hegnauer, E.A.; Furman, T. (Univ. of Virginia, Charlottesville, VA (United States). Dept. of Environmental Sciences)

1994-03-01

186

[Succession character of salt marsh vegetations in Chongming Dongtan wetland].  

PubMed

This paper studied the ecological character, importance value, aboveground biomass and its N content of salt marsh vegetations in Chongming Dongtan wetland in the process of succession. The results indicated that with the increase of altitude, the importance value of Scirpus mariqueter, a representative species at early succession stage, decreased gradually, while those of Spartina alterniflora and Phragmites australis increased. The biodiversity of the vegetations increased with succession. During growth period (from March to October), the aboveground biomass of the three species varied in single hump curve, with the peak in July and August. The N content had a decreasing trend, while the N capacity showed a single-peak curve. The estimated annual N accumulation in aboveground biomass was 383.4 t for P. australis, 50.5 t for S. mariqueter, and 39. 3 t for S. alterniflora. PMID:17650865

Yan, Qian; Lu, Jian-jian; He, Wen-shan

2007-05-01

187

Latitudinal variation in herbivore pressure in Atlantic Coast salt marshes.  

PubMed

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

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

2009-01-01

188

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

189

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

Microsoft Academic Search

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

T. Payson Wilber; W. F. Herrnkind

1984-01-01

190

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

191

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

PubMed

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

Walker, Allison K; Campbell, Jinx

2010-01-01

192

SALT MARSH TIDAL CHANNELS 295 Copyright 2004 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 29, 295309 (2004)  

E-print Network

SALT MARSH TIDAL CHANNELS 295 Copyright © 2004 John Wiley & Sons, Ltd. Earth Surf. Process March 2002; Revised 6 March 2003; Accepted 25 March 2003 ABSTRACT Salt marsh tidal channels are highly of tidal channels at China Camp Marsh in the San Francisco Bay, California. To model the planform evolution

Fagherazzi, Sergio

193

Modern distribution of salt marsh foraminifera and thecamoebians in the SeymourBelize Inlet Complex, British Columbia, Canada  

E-print Network

Modern distribution of salt marsh foraminifera and thecamoebians in the Seymour­Belize Inlet distribution along two marsh transects, in the Waump (WIR 16) and Wawwat'l (WIR 12) Indian Reserves identified; the Freshwater, Brackish and High Salt Marsh Assemblages. The Freshwater Assemblage is dominated

Patterson, Timothy

194

Sulfate reduction in a New England salt marsh  

Microsoft Academic Search

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

ROBERT W. HOWARTH; JOHN M. TEAL

1979-01-01

195

Uniformity of the nuclear and chloroplast genomes of Spartina maritima (Poaceae), a salt-marsh  

E-print Network

the populations. The lack of genetic diversity is interpreted in light of the almost exclusive vegetative-marsh species in decline along the Western European Coast G Yannic1 , A Baumel2 and M Ainouche3 1 De´partement d Scientifique de Beaulieu, 35042 Rennes, Cedex, France Spartina maritima is a salt-marsh species from European

Alvarez, Nadir

196

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

EPA Science Inventory

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

197

Northeastern Salt Marshes: Elevation Capital and Resilience to Sea Level Rise  

EPA Science Inventory

Stable tidal salt marshes exist at an elevation that is supra-optimal relative to peak biomass production, which for Spartina alterniflora, and other marsh macrophytes, follows a parabolic distribution as a function of elevation, as a surrogate for inundation frequency. In order...

198

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...

199

Annual nitrogen budget of a temperate coastal barrier salt-marsh system along a productivity gradient at low and high marsh elevation  

Microsoft Academic Search

An annual nitrogen budget was established for a temperate back barrier salt-marsh system along a productivity gradient at low and high marsh elevation. We measured plant biomass and nitrogen content in three plant compartments to deduce plant N-allocation patterns. Measurements were done along a successional sequence in a salt-marsh system. In addition, N-mineralization, wet and dry atmospheric N-deposition and sediment

Harm J. van Wijnen; Jan P. Bakker

2000-01-01

200

Quantification of Salt Marsh Carbon Stocks: Integration of Remote Sensing Data and Techniques with Field Measurements  

E-print Network

in this study show the capability of remote sensing data for the characterization of salt marsh terrain and vegetation heights and the estimation of above-ground biomass quantities. The best biomass prediction models using lidar heights reported considerably...

Kulawardhana, Ranjani W

2013-12-02

201

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

EPA Science Inventory

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

202

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...

203

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

204

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

SciTech Connect

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

Teal, J.M.

1986-06-01

205

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

Microsoft Academic Search

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

Donald F. Boesch; R. Eugene Turner

1984-01-01

206

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

NASA Astrophysics Data System (ADS)

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

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

2004-12-01

207

Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material  

USGS Publications Warehouse

Thin-layer deposition of dredged material on coastal marsh by means of high-pressure spray dredging (Jet-Spray??2) technology has been proposed as a mechanism to minimize wetland impacts associated with traditional bucket dredging technologies and to restore soil elevations in deteriorated marshes of the Mississippi River delta. The impact of spray dredging on vegetated marsh and adjacent shallow-water habitat (formerly vegetated marsh that deteriorated to open water) was evaluated in a 0.5-ha Spartina alterniflora-dominated salt marsh in coastal Louisiana. The thickness of dredged sediment deposits was determined from artificial soil marker horizons and soil elevation change was determined from sedimentation-erosion tables (SET) established prior to spraying in both sprayed and reference marshes. The vertical accretion and elevation change measurements were made simultaneously to allow for calculation of shallow (~5 m depth) subsidence (accretion minus elevation change). Measurements made immediately following spraying in July 1996 revealed that stems of S. alterniflora were knocked down by the force of the spray and covered with 23 mm of dredged material. Stems of S. alterniflora soon recovered, and by July 1997 the percent cover of S. alterniflora had increased three-fold over pre-project conditions. Thus, the layer of dredged material was thin enough to allow for survival of the S. alterniflora plants, with no subsequent colonization by plant species typical of higher marsh zones. By February 1998, 62 mm of vertical accretion accumulated at this site, and little indication of disturbance was noted. Although not statistically significant, soil elevation change was greater than accretion on average at both the spray and reference marshes, suggesting that subsurface expansion caused by increased root biomass production and/or pore water storage influence elevation in this marsh region. In the adjacent shallow water pond, 129 mm of sediment was deposited in July 1996 as a result of spraying, and despite initial shallow subsidence and continual erosion through February 1998, water bottom elevation was raised sufficiently to allow S. alterniflora to invade via rhizome growth from the adjacent marsh. Hence, thin-layer deposition of dredged material at this site was effective at restoring and maintaining marsh elevation after 1.5 years. However, if the open water sediment deposits are not soon completely stabilized via further vegetative colonization, erosion may eventually lower elevations to the level where emergent vegetation cannot persist.

Ford, M.A.; Cahoon, D.R.; Lynch, J.C.

1999-01-01

208

Herbivory affects salt marsh succession dynamics by suppressing the recovery of dominant species.  

PubMed

Disturbance can generate heterogeneous environments and profoundly influence plant diversity by creating patches at different successional stages. Herbivores, in turn, can govern plant succession dynamics by determining the rate of species replacement, ultimately affecting plant community structure. In a south-western Atlantic salt marsh, we experimentally evaluated the role of herbivory in the recovery following disturbance of the plant community and assessed whether herbivory affects the relative importance of sexual and clonal reproduction on these dynamics. Our results show that herbivory strongly affects salt marsh secondary succession by suppressing seedlings and limiting clonal colonization of the dominant marsh grass, allowing subordinate species to dominate disturbed patches. These results demonstrate that herbivores can have an important role in salt marsh community structure and function, and can be a key force during succession dynamics. PMID:24549938

Daleo, Pedro; Alberti, Juan; Pascual, Jesús; Canepuccia, Alejandro; Iribarne, Oscar

2014-05-01

209

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

210

-Spatio-temporal variation of salt marsh seedling establishment in relation to the environment -61 Journal of Vegetation Science 12: 61-74, 2001  

E-print Network

- Spatio-temporal variation of salt marsh seedling establishment in relation to the environment variation in plant establishment in the upper intertidal marsh of three southern California wet- lands intertidal marsh. Abbreviations: CCA = Canonical Correspondence Analysis; DCA = Detrended Correspondence

211

Microbial Community Composition and Denitrifying Enzyme Activities in Salt Marsh Sediments?  

PubMed Central

Denitrifying microbial communities and denitrification in salt marsh sediments may be affected by many factors, including environmental conditions, nutrient availability, and levels of pollutants. The objective of this study was to examine how microbial community composition and denitrification enzyme activities (DEA) at a California salt marsh with high nutrient loading vary with such factors. Sediments were sampled from three elevations, each with different inundation and vegetation patterns, across 12 stations representing various salinity and nutrient conditions. Analyses included determination of cell abundance, total and denitrifier community compositions (by terminal restriction fragment length polymorphism), DEA, nutrients, and eluted metals. Total bacterial (16S rRNA) and denitrifier (nirS) community compositions and DEA were analyzed for their relationships to environmental variables and metal concentrations via multivariate direct gradient and regression analyses, respectively. Community composition and DEA were highly variable within the dynamic salt marsh system, but each was strongly affected by elevation (i.e., degree of inundation) and carbon content as well as by selected metals. Carbon content was highly related to elevation, and the relationships between DEA and carbon content were found to be elevation specific when evaluated across the entire marsh. There were also lateral gradients in the marsh, as evidenced by an even stronger association between community composition and elevation for a marsh subsystem. Lastly, though correlated with similar environmental factors and selected metals, denitrifier community composition and function appeared uncoupled in the marsh. PMID:18978080

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

2008-01-01

212

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

NASA Astrophysics Data System (ADS)

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

Daly, J.; Bell, T.

2006-12-01

213

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

214

Assessing the performance of salt marsh and mangrove foraminifera as sea-level indicators  

NASA Astrophysics Data System (ADS)

Salt marsh foraminifera have proven to be an accurate sea-level indicator because their distributions on low-energy, organic coasts are vertically zoned with respect to the tidal frame and their tests are readily preserved in the sedimentary sequences. However, in contrast to salt marsh-based studies, there are fewer studies using mangrove foraminifera to reconstruct former sea level despite the importance of far field tropical localities for inferring the ice-equivalent component to relative sea-level change. This study compares the performance of salt marsh and mangrove foraminifera as sea-level indicators and attempts to reconstruct relative sea-level (RSL) change at decimeter scale using mangrove foraminifera. We chose one salt marsh site (St. Marys) and one mangrove site (Hobe Sound) along the Atlantic coast of Florida with similar climatic, biological, and geological conditions. At each site we collected modern (88 samples from 6 transects) and fossil (salt marsh and mangrove peat cores) material. We found differences between these environments with regards to the abundance, composition and diversity of the foraminiferal assemblages. The most abundant species in the salt marsh are Ammobaculites spp., Ammoastuta inepta, Haplophragmoides spp., and Trochammina inflata, while the dominant mangrove species are Arenoparrelle mexicana, Ammodiscoides spp., Glomospira spp., and Haplophragmoides spp. We quantified the optimum and tolerance of each foraminiferal species to elevations relative to tidal frame and subsequently developed salt marsh and mangrove transfer functions (TF). The TFs estimate vertical uncertainty of ~ ± 0.2 m, indicating that precise reconstructions of RSL are possible. The fossil mangrove core is dominated by species similar to the modern assemblages. We applied the mangrove-based TF and combined this with a preliminary chronology based on 210Pb and 14C dates to reconstruct RSL, which was validated against regional tide-gauge records, demonstrating its usefulness in assessing sea level changes in tropical to semi-tropical locations.

Liu, S.; Horton, B. P.; Toscano, M. A.; Engelhart, S. E.; Hawkes, A.

2011-12-01

215

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

Microsoft Academic Search

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

Mark D. Bertness; Patrick J. Ewanchuk

2002-01-01

216

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

Microsoft Academic Search

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

Ole R. Therkildsen; Thomas Bregnballe

2006-01-01

217

Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay,  

E-print Network

Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has

Boyer, Edmond

218

Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes?  

Microsoft Academic Search

The invasion of Mont-Saint-Michel Bay salt marshes (France) by a grass species (Elymus athericus) has led to important changes in vegetation cover, which is likely to modify the habitat for many invertebrates. Some of them constitute the main food items for several fish species, such as young sea bass (Dicentrarchus labrax) and sand goby (Pomatoschistus minutus), that feed in salt

P. Laffaille; J. Petillon; E. Parlier; L. Valery; F. Ysnel; A. Radureau; E. Feunteun; J.-C. Lefeuvre

2005-01-01

219

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

NASA Astrophysics Data System (ADS)

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

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

2006-08-01

220

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

PubMed

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

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

1991-01-01

221

Aggregative responses of brent geese on salt marsh and their impact on plant community dynamics  

Microsoft Academic Search

The aggregative responses and habitat preferences of a generalist herbivore, the dark-bellied brent goose Branta bernicla bernicla, feeding on salt marshes are examined in relation to vegetation community characteristics and the abundances of individual\\u000a plant species. In the autumn, feeding was strongly concentrated on the low marsh, which had the highest biomass of the preferred\\u000a food plant, Salicornia europaea. There

J. Marcus Rowcliffe; Andrew R. Watkinson; William J. Sutherland

1998-01-01

222

Strontium 90 in Maize Field, Cattail Marsh and Oakwood Ecosystems Author(s): J. D. Ovington and D. B. Lawrence  

E-print Network

Strontium 90 in Maize Field, Cattail Marsh and Oakwood Ecosystems Author(s): J. D. Ovington and D Ecology. http://www.jstor.org #12;STRONTIUM 90 IN MAIZE FIELD, CATTAIL MARSH AND OAKWOOD ECOSYSTEMS BY J annualfieldcrop,maize,ZeacmaysL., andtwonaturalecosystemsdomin- ated byperennials,a marshofnarrowleavedcattail

Minnesota, University of

223

Middle to Late Holocene Fluctuations of C3 and C4 Vegetation in a Northern New England Salt Marsh, Sprague Marsh, Phippsburg Maine  

SciTech Connect

A 3.1 meter sediment core was analyzed for stable carbon isotope composition of organic matter and higher plant leaf wax (HPLW) lipid biomarkers to determine Holocene shifts in C{sub 3} (higher high marsh) and C{sub 4} (low and/or high marsh) plant deposition at the Sprague River Salt Marsh, Phippsburg, Maine. The carbon isotope composition of the bulk sediment and the HPLW parallel each other throughout most of the core, suggesting that terrestrial plants are an important source of organic matter to the sediments, and diagenetic alteration of the bulk sediments is minimal. The current salt marsh began to form 2500 cal yr BP. Low and/or high C{sub 4} marsh plants dominated deposition at 2000 cal yr BP, 700 cal yr BP, and for the last 200 cal yr BP. Expansion of higher high marsh C{sub 3} plants occurred at 1300 and 600 cal yr BP. These major vegetation shifts result from a combination of changes in relative sea-level rise and sediment accumulation rates. Average annual carbon sequestration rates for the last 2500 years approximate 40 g C yr{sup -1} m{sup -2}, and are in strong agreement with other values published for the Gulf of Maine. Given that Maine salt marshes cover an area of {approx}79 km{sup 2}, they represent an important component of the terrestrial carbon sink. More detailed isotopic and age records from a network of sediment cores at Sprague Marsh are needed to truly evaluate the long term changes in salt marsh plant communities and the impact of more recent human activity, including global warming, on salt marsh vegetation.

Johnson, B J; Moore, K A; Lehmann, C; Bohlen, C; Brown, T A

2006-05-26

224

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. PMID:19411268

Pétillon, Julien; Montaigne, William; Renault, David

2009-01-01

225

Trace metal concentrations in Spartina densiflora and associated soil from a Patagonian salt marsh.  

PubMed

The objectives of this study were to (i) assess in situ trace metal concentrations in soil and in Spartina densiflora in a Patagonian salt marsh (Rawson, Chubut, Argentina) and (ii) investigate the relationship between trace metal concentrations in soils and in plants to improve our knowledge regarding the ability of S. densiflora to take up and accumulate trace metals from the soil within its native region. Our results indicate that the soil and S. densiflora exhibit low metal concentrations in the Rawson salt marsh. S. densiflora accumulates Zn in below- and above-ground plant structures and Cr in below-ground parts. These results suggest at the time of this study there is scarce human impact associated with metals in the Rawson salt marsh. PMID:25457812

Idaszkin, Yanina L; Bouza, Pablo J; Marinho, Carmen H; Gil, Mónica N

2014-12-15

226

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

227

A floristic and vegetational study of a latitudinal gradient of salt marshes in South-Central Chile  

Microsoft Academic Search

C. San Martín, M. Subiabre and C. Ramírez. 2006. A floristic and vegetational study of a latitudinal gradient of salt marshes in South-Central Chile. Cien. Inv. Agr. (in English) 33(1): 33-40. Salt marshes are brackish swamps formed in the estuaries of the rivers. The flora and vegetation of three marshes located at Puerto Saavedra (Cautín province, 38º 46' S and

C. San Martín; M. Subiabre; C. Ramírez

228

The burrowing crab Neohelice granulata affects the root strategies of the cordgrass Spartina densiflora in SW Atlantic salt marshes  

Microsoft Academic Search

Salt marshes are among the most productive systems of the world, with plant primary production limited by soil oxygen deficiency and nutrient availability. Nevertheless, root adaptations to anoxia and nutrient acquisition are different and often incompatible. The SW Atlantic salt marshes are characterized by high densities of the deep (up to 1 m) burrowing crab Neohelice granulata (Dana, 1851) that may

Pedro Daleo; Oscar Iribarne

2009-01-01

229

[Vegetation influence on nutrients distribution in pore water of salt marsh sediment].  

PubMed

The variations of nutrients in pore water of salt marsh sediment were surveyed in the middle intertidal zone of Chongming Dongtan during August 2007 to May 2008 to identify plant impact on nutrients distribution. The results show that NH4(+) -N and PO4(3-) -P concentrations are lower in pore water of Spartina alterniflora and Phragmites australis zones than in bare flat, and specially, NH4(+) -N concentrations in summer and autumn decrease by one more orders of magnitude. Compared to winter, nutrients concentrations are obviously higher during the period of plant growth, and plant biomass is clearly correlative to nitrogen and phosphorus. Vegetation growth influences nitrogen content intensively. NH4(-) -N concentrations in Spartina alterniflora and Phragmites australis zones are 44.21 and 74.38 micromol x L(-1) respectively, distinctly lower than that in bare flat and Scirpus mariquete zone (340.14 and 291.87 micromol x L(-1) respectively). Moreover, NO(x)(-) -N concentration is one to two order(s) of magnitude lower than NH4(+) -N, and its highest value exists in Phragmites australis zone (5.94 micromol x L(-1)). The results of molecule diffusive flux of nutrients in the surface sediment-overlying water interface indicate that marsh sediment is the source for SiO3(2-) -Si, NH4(+) -N and PO4(3-) -P, and the rank for NO(x)(-) -N (NO3(-) -N + NO2(-) -N), and NO(x)(-) -N flux from overlying water to sediment [16.23 micromol x (m2 x h)(-1)] is higher than NH4(+) -N flux from sediment to overlying water [15.53 micromol x (m2 x h)(-1)]. Vegetation growth accommodates nutrient structure of the estuarine ecosystem by affecting sediment-water interface mass flux and nutrient ratios in pore water and overlying water. PMID:20063731

Wang, Wei-Wei; Li, Dao-Ji; Gao, Lei

2009-11-01

230

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

USGS Publications Warehouse

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

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

2004-01-01

231

Lithium in the brines of Fish Lake Valley and Columbus Salt Marsh, Nevada  

USGS Publications Warehouse

Analyses of waters-from springs in Nevada have led to the identification of an area containing anomalous amounts of lithium northwest of the Clayton Valley-area. Fish Lake Valley and Columbus Salt Marsh contain waters having, relatively high lithium and potassium concentrations. At least a part of these waters is probably derived from the leaching of Tertiary rocks containing saline minerals. The high-lithium waters at Columbus Salt Marsh could be derived not only by the leaching of rocks with a high soluble lithium ands, potassium content but also by subsurface outflow from Fish Lake Valley.

Smith, C.L.; Meier, Allen L.; Downey, H.D.

1977-01-01

232

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

Microsoft Academic Search

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

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

2003-01-01

233

-Secondary succession on a high salt marsh at different grazing intensities -123 Journal of Coastal Conservation 9: 123-134, 2003  

E-print Network

- Secondary succession on a high salt marsh at different grazing intensities - 123 Journal part of German salt marshes following abandonment or reduction of grazing. Its speed and effect on the biodiversity of salt marshes has been discussed in the literature. Permanent plot studies show site- dependent

Kleyer, Michael

234

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

235

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

NASA Astrophysics Data System (ADS)

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

Murphy, S.; Voulgaris, G.

2001-05-01

236

Importance of biogeomorphic and spatial properties in assessing a tidal salt marsh vulnerability to sea-level rise  

USGS Publications Warehouse

We evaluated the biogeomorphic processes of a large (309 ha) tidal salt marsh and examined factors that influence its ability to keep pace with relative sea-level rise (SLR). Detailed elevation data from 1995 and 2008 were compared with digital elevation models (DEMs) to assess marsh surface elevation change during this time. Overall, 37 % (113 ha) of the marsh increased in elevation at a rate that exceeded SLR, whereas 63 % (196 ha) of the area did not keep pace with SLR. Of the total area, 55 % (169 ha) subsided during the study period, but subsidence varied spatially across the marsh surface. To determine which biogeomorphic and spatial factors contributed to measured elevation change, we collected soil cores and determined percent and origin of organic matter (OM), particle size, bulk density (BD), and distance to nearest bay edge, levee, and channel. We then used Akaike Information Criterion (AICc) model selection to assess those variables most important to determine measured elevation change. Soil stable isotope compositions were evaluated to assess the source of the OM. The samples had limited percent OM by weight (-3, indicating that the soils had high mineral content with a relatively low proportion of pore space. The most parsimonious model with the highest AICc weight (0.53) included distance from bay's edge (i.e., lower intertidal) and distance from levee (i.e., upper intertidal). Close proximity to sediment source was the greatest factor in determining whether an area increased in elevation, whereas areas near landward levees experienced subsidence. Our study indicated that the ability of a marsh to keep pace with SLR varied across the surface, and assessing changes in elevation over time provides an alternative method to long-term accretion monitoring. SLR models that do not consider spatial variability of biogeomorphic and accretion processes may not correctly forecast marsh drowning rates, which may be especially true in modified and urbanized estuaries. In light of SLR, improving our understanding of elevation change in these dynamic marsh systems will play a crucial role in forecasting potential impacts to their sustainability and the survival of these ecosystems.

Thorne, Karen M.; Elliott-Fisk, Deborah L.; Wylie, Glenn D.; Perry, William M.; Takekawa, John Y.

2014-01-01

237

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

ERIC Educational Resources Information Center

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

Brevard County School Board, Cocoa, FL.

238

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

239

Dynamics of bacterial community succession in a salt marsh chronosequence: evidences for temporal niche partitioning.  

PubMed

The mechanisms underlying community assembly and promoting temporal succession are often overlooked in microbial ecology. Here, we studied an undisturbed salt marsh chronosequence, spanning over a century of ecosystem development, to understand bacterial succession in soil. We used 16S rRNA gene-based quantitative PCR to determine bacterial abundance and multitag 454 pyrosequencing for community composition and diversity analyses. Despite 10-fold lower 16S rRNA gene abundances, the initial stages of soil development held higher phylogenetic diversities than the soil at late succession. Temporal variations in phylogenetic ?-diversity were greater at initial stages of soil development, possibly as a result of the great dynamism imposed by the daily influence of the tide, promoting high immigration rates. Allogenic succession of bacterial communities was mostly driven by shifts in the soil physical structure, as well as variations in pH and salinity, which collectively explained 84.5% of the variation concerning community assemblage. The community assembly data for each successional stage were integrated into a network co-occurrence analysis, revealing higher complexity at initial stages, coinciding with great dynamism in turnover and environmental variability. Contrary to a spatial niche-based perspective of bacterial community assembly, we suggest temporal niche partitioning as the dominant mechanism of assembly (promoting more phylotype co-occurrence) in the initial stages of succession, where continuous environmental change results in the existence of multiple niches over short periods of time. PMID:24739625

Dini-Andreote, Francisco; de Cássia Pereira e Silva, Michele; Triadó-Margarit, Xavier; Casamayor, Emilio O; van Elsas, Jan Dirk; Salles, Joana Falcão

2014-10-01

240

Crabs Mediate Interactions between Native and Invasive Salt Marsh Plants: A Mesocosm Study  

PubMed Central

Soil disturbance has been widely recognized as an important factor influencing the structure and dynamics of plant communities. Although soil reworkers were shown to increase habitat complexity and raise the risk of plant invasion, their role in regulating the interactions between native and invasive species remains unclear. We proposed that crab activities, via improving soil nitrogen availability, may indirectly affect the interactions between invasive Spartina alterniflora and native Phragmites australis and Scirpus mariqueter in salt marsh ecosystems. We conducted a two-year mesocosm experiment consisting of five species combinations, i.e., monocultures of three species and pair-wise mixtures of invasive and native species, with crabs being either present or absent for each combination. We found that crabs could mitigate soil nitrogen depletion in the mesocosm over the two years. Plant performance of all species, at both the ramet-level (height and biomass per ramet) and plot-level (density, total above- and belowground biomass), were promoted by crab activities. These plants responded to crab disturbance primarily by clonal propagation, as plot-level performance was more sensitive to crabs than ramet-level. Moreover, crab activities altered the competition between Spartina and native plants in favor of the former, since Spartina was more promoted than native plants by crab activities. Our results suggested that crab activities may increase the competition ability of Spartina over native Phragmites and Scirpus through alleviating soil nitrogen limitation. PMID:24023926

Zhang, Xiao-dong; Jia, Xin; Chen, Yang-yun; Shao, Jun-jiong; Wu, Xin-ru; Shang, Lei; Li, Bo

2013-01-01

241

Classification of salt marsh vegetation using edaphic and remote sensing-derived variables  

NASA Astrophysics Data System (ADS)

Salt marsh plant communities are known for their striking patterns of vertical zonation. Two of the most important edaphic parameters that affect species distribution patterns are soil salinity and waterlogging, both of which are related to topographical variations and distance to the water. The primary objective of this study was to evaluate whether information on elevation and distance derived through remote sensing could be used to predict plant distributions in a southeastern United States salt marsh. We classified four marsh vegetation classes (tall Spartina alterniflora, medium S. alterniflora/short S. alterniflora, marsh meadow, and Borrichia frutescens/Juncus roemerianus) based on landscape metrics obtained from a light detection and ranging (LIDAR)-derived digital elevation model (DEM) and compared results to a classification based on field-collected edaphic variables. Our secondary objective was to compare the performance of linear discriminant analysis (LDA) with non-parametric classification and regression trees (CART) for these classifications. Models based on the edaphic variables soil water content, salinity, and redox potential attained accuracies of 0.62 and 0.71 with LDA and CART, respectively. When the remote sensing-derived variables DEM elevation, slope, distance to the mean high water line, and distance to upland area were used, classification accuracies improved to 0.78 for LDA and 0.79 for CART. Our results suggest that remote sensing-derived metrics can capture edaphic gradients effectively, which makes them especially suited to landscape level analyses of salt marsh plant habitats, with potential application for predicting the effects of sea level rise on salt marsh plant distribution.

Hladik, Christine; Alber, Merryl

2014-03-01

242

Long-term CH3Br and CH3Cl flux measurements in temperate salt marshes   

E-print Network

Fluxes of CH3Br and CH3Cl and their relationship with potential drivers such as sunlight, temperature and soil moisture, were monitored at fortnightly to monthly intervals for more than two years at two contrasting temperate salt marsh sites...

Blei, Emanuel; Heal, Mathew R; Heal, Kate V

243

Characterization of humic substances in salt marsh soils under sea rush ( Juncus maritimus)  

NASA Astrophysics Data System (ADS)

Humic substances (HS) from salt marsh soils were characterized and the relationships among HS composition and some geochemical factors were analysed. For this, three salt marshes with the same vegetation cover ( Juncus maritimus), but with different geochemical characteristics, were selected. The qualitative characterization of the soil humic acids and fulvic acids was carried out by elemental analysis, FTIR spectroscopy, fluorescence spectroscopy and VACP/MAS 13C NMR spectroscopy. HS from salt marsh soils under sea rush ( Juncus maritimus) displayed some shared characteristics such as low degree of humification, low aromatic content and high proportion of labile compounds, mainly polysaccharides and proteins. However, although the three salt marsh soils under study were covered by the same type of vegetation, the HS showed some important differences. HS composition was found to be determined not only by the nature of the original organic material, but also by environmental factors such as soil texture, redox conditions and tidal influence. In general, an increase in the humification process appeared to be related to aerobic conditions and predominance of sand in the mineral fraction of the soil, while the preservation of labile organic compounds may be associated with low redox potential values and fine soil texture.

Santín, C.; González-Pérez, M.; Otero, X. L.; Vidal-Torrado, P.; Macías, F.; Álvarez, M. Á.

2008-09-01

244

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

Microsoft Academic Search

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

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

2008-01-01

245

The effect of fluctuations in tidal inundation frequency on a salt-marsh vegetation  

Microsoft Academic Search

Over a period of 15 years recordings were made of the species cover in permanent plots on the salt marsh of one of the West Frisian Islands, Schiermonnikoog (The Netherlands). Correlations between annual changes in the cover of the major species, and fluctuations in the monthly frequency of inundation by seawater were studied. First, a spectral analysis was carried out

H. Olff; J. P. Bakker; L. F. M. Fresco

1988-01-01

246

Edaphic characterization and soil ionic composition influencing plant zonation in a semiarid Mediterranean salt marsh  

Microsoft Academic Search

Soil characteristics and plant zonation were studied in a semiarid Mediterranean salt marsh in SE Spain. According to topographic sequences and plants distribution, two transects were established from the border of La Mata lagoon to the upland vegetation limit and soils were described and analysed. Regularly spaced plots were established in these transects in accordance with the stands of vegetation

J. Álvarez Rogel; R. Ortiz Silla; F. Alcaraz Ariza

2001-01-01

247

Mapping mixed vegetation communities in salt marshes using airborne spectral data  

Microsoft Academic Search

The aim of this study is to evaluate a new neural network classifier using spectrally sampled image data to map mixed halophytic vegetation in tidal environments. The work is based on the concept of vegetation communities, mixtures of several species, characteristic of salt marshes. The study site is the Venice lagoon, and the material available is a spectrally sampled Compact

Cheng Wang; Massimo Menenti; Marc-Philippe Stoll; Enrica Belluco; Marco Marani

2007-01-01

248

Can salt marsh plants influence levels and distribution of DDTs in estuarine areas?  

Microsoft Academic Search

Sediments are depositories of toxic substances such as organochlorine pesticides and there is a global need for their removal in contaminated environments. Studies that combine contaminated sediments and phytoremediation are relatively recent and their number has been increasing. This work aimed to investigate whether salt marsh plants (sea club-rush Scirpus maritimus, sea rush Juncus maritimus and sea purslane Halimione portulacoides)

Pedro N. Carvalho; Pedro Nuno R. Rodrigues; Rafael Evangelista; M. Clara P. Basto; M. Teresa S. D. Vasconcelos

2011-01-01

249

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

Microsoft Academic Search

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

C. Marisa; R. Almeida; Adriano A. Bordalo; M. Teresa; S. D. Vasconcelos

250

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

Microsoft Academic Search

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

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

2005-01-01

251

Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities  

Microsoft Academic Search

This paper reports changes in vegetation distribution and species cover in relation to soil factors and hydrology in a semiarid Mediterranean salt marsh adjacent to the Mar Menor saline lagoon. Species cover, soil salinity, and the groundwater level were monitored between 1991 and 1993 and between 2002 and 2004, and total organic carbon, total nitrogen, total phosphorus, nitrates, ammonium and

J. Álvarez-Rogel; F. J. Jiménez-Cárceles; M. J. Roca; R. Ortiz

2007-01-01

252

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

E-print Network

frequency of elevations between 0 and 0.5 m. Typical conceptual and numerical models of salt-marsh for and plant colonization (5­7). However, the evidence points to abrupt transitions to one of two distinct the energy dissipation caused by whitecapping, depth-induced breaking, and bottom friction limit the growth

Fagherazzi, Sergio

253

Temporal and spatial variation in methyl bromide emissions from a salt marsh   

E-print Network

measurements of CH3Br emissions from a salt marsh in Scotland (56°00?N, 2°35?W) were made during one year using eight static enclosures. Net emissions showed both strong seasonal and diurnal cycles. Day-to-day maxima in emissions were associated with sunny days...

Drewer, Julia; Heal, Mathew R; Heal, Kate V; Smith, Keith A

2006-01-01

254

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

Microsoft Academic Search

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

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

2001-01-01

255

CONIDIA MORPHOLOGY AND ECOLOGICAL CHARACTERISTICS AS DIAGNOSTIC TOOLS FOR CLAVICEPS PURPUREA FROM SALT MARSH HABITATS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Claviceps purpurea associated with grass hosts in salt marsh habitats, also known as G3 ergot, can be differentiated from C. purpurea infecting grasses in other habitats using genetic, chemical and morphological criteria. However, only morphological analysis can be used on herbarium specimens, which...

256

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...

257

DECEMBER, 1976 MOSQUITO NEWS W6 9 437 BEHAVIORAL CHANGES IN THE SALT MARSH MOSQUITO,  

E-print Network

DECEMBER, 1976 MOSQUITO NEWS W6 9 437 BEHAVIORAL CHANGES IN THE SALT MARSH MOSQUITO, AEDES SOLLICITANS, AS A RESULT OF INCREASED PHYSIOLOGICAL AGE' WAYNE'J. CRANS, JERE DOWNING MARC E. SLAFF Mosquito for less than week the inland site and that few bites would be received from mosquitoes. When the nuisance

258

Nitrogen resorption from senescing leaves of three salt marsh plant species  

Microsoft Academic Search

Seasonalvariation in leaf nitrogen of mature green and senescent leaves and nitrogenresorption efficiency in three plants (Spartina maritima, Halimioneportulacoides and Arthrocnemum perenne) of aTagus estuary salt marsh are reported. Total nitrogen concentrations in greenand senescent leaves were higher during winter (December and March). Soilinorganic nitrogen availability showed an opposite pattern with higherconcentrations during summer (June and September) when total leaf

P. Cartaxana; F. Catarino

2002-01-01

259

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

Microsoft Academic Search

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

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

2008-01-01

260

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

Microsoft Academic Search

This work evaluates the role of a plant community in mercury (Hg) stabilization and mobility in a contaminated Portuguese salt marsh. With this aim, the distribution of Hg in below and aboveground tissues, as well as the metal partitioning between cellular fractions (soluble and insoluble) in four different species (Triglochin maritima L., Juncus maritimus Lam, Sarcocornia perennis (Miller) A.J. Scott,

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

2009-01-01

261

GUIDANCE DOCUMENT ON THE BIOREMEDIATION OF OIL-CONTAMINATED SALT MARSHES.  

EPA Science Inventory

A comprehensive guidance document that includes all known information about the implementation of bioremediation for cleanup of oil-contaminated coastal salt marshes was developed and the project completed. The document is the second in a series of two that has been produced. The...

262

Diet choice in an omnivorous salt-marsh crab: different food types, body size,  

E-print Network

Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat 24 February 2003; accepted 18 March 2003 Abstract Studies of diet choice by omnivores have the potential to form conceptual links between studies of diet choice by herbivores, frugivores, detritivores

Pennings, Steven C.

263

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

264

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

265

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

PubMed Central

Methane (CH4) flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23??g CH4?m?2?day?1 for each g?N?m?2?year?1 applied) after 7?months of fertilization. To test the reason behind this increased CH4 flux, we conducted a microcosm experiment altering both nitrogen and carbon availability under aerobic and anaerobic conditions. Methanogenesis appeared to be both nitrogen and carbon (acetate) limited. N and C each increased methanogenesis by 18%, and together by 44%. In contrast, methanotrophy was stimulated by carbon (methane) addition (830%), but was unchanged by nitrogen addition. Sequence analysis of the sediment methylotroph community with the methanol dehydrogenase gene (mxaF) revealed three distinct clades that fall outside of known lineages. However, in agreement with the microcosm results, methylotroph abundance (assayed by qPCR) and composition (assayed by terminal restriction fragment length polymorphism analysis) did not vary across the experimental nitrogen gradient in the field. Together, these results suggest that nitrogen enrichment to salt marsh sediments increases methane flux by stimulating the methanogen community. PMID:22470369

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

2012-01-01

266

Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes?  

NASA Astrophysics Data System (ADS)

The invasion of Mont-Saint-Michel Bay salt marshes (France) by a grass species ( Elymus athericus) has led to important changes in vegetation cover, which is likely to modify the habitat for many invertebrates. Some of them constitute the main food items for several fish species, such as young sea bass ( Dicentrarchus labrax) and sand goby ( Pomatoschistus minutus), that feed in salt marsh creeks during high tides. As a result, fish nursery functions of salt marshes could be modified by the E. athericus invasion. In order to test this hypothesis, gut contents of the two most abundant fish species (sea bass and sand goby) were compared before and after E. athericus invasion in the same salt marsh creek and using the same methodology. The accessibility and availability of the main food item, the semi-terrestrial amphipod Orchestia gammarella, were estimated and compared between invaded (dominated by E. athericus) and original areas (dominated by Atriplex portulacoides). Gut content analysis showed a significantly greater percentage of fish leaving with empty guts from E. athericus areas than from A. portulacoides areas. The sea bass diet composition study showed a major shift in the relative importance of the main food items: before E. athericus invasion, diets were dominated by the semi-terrestrial species O. gammarella, whereas after the E. athericus invasion they were dominated by a marine mysid Neomysis integer. The same trend was found for sand gobies, with a shift of the main food item from O. gammarella before invasion to the polychaete Hediste diversicolor after invasion. These trophic changes may be explained by the lower accessibility and availability of O. gammarella in invaded communities than in natural ones. The E. athericus invasion, observed throughout northern Europe, is thus likely to disturb trophic function of natural salt marshes for fish. This preliminary study of the E. athericus invasion is also an illustration that invasive species are an urgent problem in conservation biology.

Laffaille, P.; Pétillon, J.; Parlier, E.; Valéry, L.; Ysnel, F.; Radureau, A.; Feunteun, E.; Lefeuvre, J.-C.

2005-12-01

267

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

268

The new CutSprof sampling tool and method for micromorphological and microfacies analyses of subsurface salt marsh sediments, Algarve, Portugal  

NASA Astrophysics Data System (ADS)

A new tool and method for collecting undisturbed subsurface samples in estuarine environments by means of trenching, timbering and sectioning is presented. Smoothing of sidewalls is achieved by a so-called cutting sediment profiler (CutSprof), while water draining into the trench is cleared by pumping. From smoothed sidewall sections, undisturbed thin sediment slices can then be collected for micromorphological and microfacies analyses. Results demonstrating the successful application of this procedure are presented for salt marshes of the Bensafrim River estuary (Lagos, Algarve, Portugal). In addition to palaeo-reconstructions in salt marsh settings, the CutSprof would be highly suitable in various other research domains as well as for environmental management purposes, particularly where sampling below the groundwater table is desirable to explore, for example, animal-sediment relationships in tidal-flat and mangrove ecosystems as well as the dynamics of coastal wetlands today threatened by ever-increasing anthropogenic influence.

Araújo-Gomes, João; Ramos-Pereira, Ana

2015-02-01

269

Stability of Juncus roemerianus patches in a salt marsh  

Microsoft Academic Search

In a Virginia (USA) marsh undergoing transgression due to rising sea level, we examined the stability of the boundary between\\u000a nearly monotypic patches ofJuncus roemerianus and adjacent plant communities for 6 years. Patch stability was evaluated by examining interannual changes in 5 cover classes:J. roemerianus, Spartina alterniflora, S. patens, Distichlis spicata, and wrack. Patches were chosen at four sites ranging

Mark M. Brinson; Robert R. Christian

1999-01-01

270

The influence of mosquito control recirculation ditches on plant biomass, production and composition in two San Francisco Bay salt marshes  

NASA Astrophysics Data System (ADS)

Vegetation of two San Francisco Bay, California, U.S.A. tidal marshes was examined to determine the effects of recirculation ditches designed to eliminate mosquito-breeding. Salicornia virginica L. biomass and production in Petaluma Marsh and plant species composition in Suisun Marsh were measured with respect to distance from ditches and natural channels. In Petaluma Marsh, both annual above-ground production estimates and infrared aerial photographs indicated that S. virginica growth rates were higher near ditches than in the open marsh. In the floristically diverse, less saline Suisun Marsh, there was a displacement of the more salt tolerant S. virginica by the less tolerant Juncus balticus Willd. and a significantly greater number of species near the ditches. Results in both marshes are correlated with low groundwater salinities near ditches and suggest that tidal circulation within ditches locally ameliorates extremes in soil conditions.

Balling, Steven S.; Resh, Vincent H.

1983-02-01

271

Metal pollution in a salt marsh and its effect on sheep.  

PubMed

In a salt marsh in the Westerschelde, samples were taken from soil and vegetation during 15 months. Concentrations of Cd, Pb, Cu, Zn, Mn, and Fe were measured and compared with levels of these metals in livers, kidneys, and faeces of sheep grazing there. The contamination extent of soil ranges from 2 (Cu) to 8 (Cd); in spring some plants exceed the advised maximum tolerable level of dietary Cd for sheep. However, levels of metals in organs from sheep do not indicate intoxication, nor did clinical inspections and autopsies. It is suggested that sheep exhibit a selective consumption behaviour and that the bioavailability of the metals in this marsh is low. PMID:3468924

Baars, A J; van Beek, H; de Graaf, G J; Spierenburg, T J; Beeftink, W G; Nieuwenhuize, J

1986-01-01

272

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

SciTech Connect

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

Stout, J.P.

1984-12-01

273

The effects of metal and nutrient addition on Ribbed Mussels, Geukensia demissa, in the Great Sippewissett Salt Marsh and Eel Pond  

E-print Network

the potential effects of nutrient loading and heavy metal pollution on salt marshes, researchers established highly contaminated with heavy metals. Nutrient additions did not promote or deter the health of mussels Marsh plots, perhaps a result of metal contamination. Keywords Salt marsh, nutrients, heavy metals

Vallino, Joseph J.

274

Competition and Salt-Marsh Plant Zonation: Stress Tolerators May Be Dominant Competitors Author(s): Nancy C. Emery, Patrick J. Ewanchuk, Mark D. Bertness  

E-print Network

Competition and Salt-Marsh Plant Zonation: Stress Tolerators May Be Dominant Competitors Author of America COMPETITION AND SALT-MARSH PLANT ZONATION: STRESS TOLERATORS MAY BE DOMINANT COMPETITORS NANCY C competition interacts with physical stress to structuresalt-marsh plant communities across a naturalgradient

Bertness, Mark D.

275

SALT MARSH HABITAT FROM A FISH EYE VIEW: A TEST OF THE DIMENSIONLESS INDEX OF HABITAT COMPLEXITY  

EPA Science Inventory

Salt marshes are considered important foraging and predator refuge areas for fish, but these functions are rarely measured. The goal of this study was to examine the relationship between the structural complexity of the habitat and fish size in marshes subjected to different wat...

276

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

PubMed

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

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

2008-01-01

277

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

Microsoft Academic Search

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

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

1986-01-01

278

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

279

High site fidelity and low site connectivity in temperate salt marsh fish populations: a stable isotope approach  

Microsoft Academic Search

Adult and juvenile fish utilise salt marshes for food and shelter at high tide, moving into adjacent sublittoral regions during\\u000a low tide. Understanding whether there are high levels of site fidelity for different species of coastal fish has important\\u000a implications for habitat conservation and the design of marine protected areas. We hypothesised that common salt marsh fish\\u000a species would demonstrate

Benjamin C. GreenDavid; David J. Smith; Jonathan Grey; Graham J. C. Underwood

280

Effects of Life History Strategy on Fish Distribution and Use of Estuarine Salt Marsh and Shallow-Water Flat Habitats  

Microsoft Academic Search

To assess the potential for habitat isolation effects on estuarine nekton, we used two species with different dispersal abilities\\u000a and life history strategies, mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides) to examine: (1) distribution trends among estuarine shallow-water flat and various intertidal salt marsh habitats and (2)\\u000a the influence of salt marsh habitat size and isolation. Collections were conducted using

David L. Meyer; Martin H. Posey

2009-01-01

281

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

282

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...

283

Seasonal changes in the microbial community of a salt marsh, measured by phospholipid fatty acid analysis  

Microsoft Academic Search

Microbial activity within the environment can have distinct geochemicaleffects, and so changes in a microbial community structure can result ingeochemical change. We examined seasonal changes in both the microbialcommunityand the geochemistry of an inter-tidal salt marsh in north-west England tocharacterise biogeochemical processes occurring at this site.Phospholipid fatty acid (PLFA) analysis of sediment samples collected atmonthly intervals was used to measure

M. J. Keith-Roach; N. D. Bryan; R. D. Bardgett; F. R. Livens

2002-01-01

284

Population genetics of the mangrove salt marsh snake, Nerodia clarkii compressicauda , in a linear, fragmented habitat  

Microsoft Academic Search

The mangrove salt marsh snake (Nerodia clarkii compressicauda) occupies a unique and disappearing habitat in much of coastal southern Florida. Given extensive habitat fragmentation and\\u000a high predation pressure in open spaces, it seems likely that populations of N. c. compressicauda consist of isolated groups of related individuals. To assess the degree of population subdivision in this species we genotyped\\u000a a

Kevin P. Jansen; Henry R. Mushinsky; Stephen A. Karl

2008-01-01

285

The distribution of Juncus roemerianus in the salt marshes of North America  

Microsoft Academic Search

Although scattered individuals ofJuncus roemerianus Scheele may be found northward in New Jersey, Long Island, New York, Connecticut and southward along the Laguna Madre in\\u000a Texas, Mexico and on the Caribbean islands, the species is most prevalent along the south Atlantic and Gulf coasts of the\\u000a eastern United States. Here there are approximately 3,174,333 hectares of salt marsh of which

Lionel N. Eleuterius

1976-01-01

286

A conceptual model of salt marsh plant distribution in coastal dunes of southeastern Spain  

Microsoft Academic Search

The main objectives of this study were to identify a small of edaphic factors that could be related to vegetation distribution\\u000a in a coastal dune salt marsh system in the Southeast of Spain and to establish a simple conceptual model to describe the relationships\\u000a between these soil factors and the main plant communities. Soil and vegetation data were obtained from

José Álvarez-Rogel; Juan José Martínez-Sánchez; Lucía Carrasco Blázquez; Carmen M. Marín Semitiel

2006-01-01

287

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

288

Home ranges of brown hares in a natural salt marsh: comparisons with agricultural systems  

Microsoft Academic Search

This is the first study on spatial behaviour of brown haresLepus europaeus Pallas, 1778 based on radio-telemetry in a natural system, which we contrast with data from agricultural systems. Radio tracking\\u000a took place in a Dutch salt marsh over a 10-month period, with intensive tracking sessions during April\\/May and December\\/January.\\u000a Six hares could be followed in both periods and in

Peter J. G. Kunst; René van der Wal; Sip van Wieren

2001-01-01

289

A comparative study of the tolerance of salt marsh plants to manganese  

Microsoft Academic Search

Summary Salicornia europaea, Puccinellia maritima, Triglochin maritima, Aster tripolium, Plantago maritima, Armeria maritima, Juncus gerardii andFestuca rubra, collected as seed from a salt marsh at Portaferry, County Down, were grown on saline (340 mM NaCl) and non saline nutrient solutions at five concentrations of manganese sulphate (0.025–10.0 mM). After an eight week growing period, shoot and root yields and the

A. Cooper

1984-01-01

290

Nesting habitat of Belding’s Savannah sparrows in coastal salt marshes  

Microsoft Academic Search

Although the Belding’s Savannah sparrow (Passerculus sandwichensis beldingl) is listed as endangered in California, little is known about the factors that affect its abundance and distribution. Numbers\\u000a of breeding pairs, nesting territory sizes, and vegetation characteristics were measured at fourteen study plots in two southern\\u000a California coastal wetlands, Tijuana Estuary and Los Peñasquitos Lagoon. Sparrows nested in middle salt marsh

Abby N. Powell

1993-01-01

291

Pyrite formation and the measurement of sulfate reduction in salt marsh sediments  

Microsoft Academic Search

A new method was used to study the formation of pyrite plus elemental sulfur during ³⁵SOâ\\/sup 2 -\\/ reduction experiments in salt marsh sediments: the reduction with chromium(II) of pyrite and elemental sulfur to hydrogen sulfide. It is both more specific and more sensitive than the previous method, the oxidation of pyrite and elemental sulfur to sulfate by aqua regia,

ROBERT W. HOWARTH; SUSAN MERKEL

1984-01-01

292

Tidal Flooding and Vegetation Patterns in a Salt Marsh Tidal Creek Imaged by Low-altitude Balloon Aerial Photography  

NASA Astrophysics Data System (ADS)

Inundation of marsh surfaces by tidal creek flooding has implications for the headward erosion of salt marsh creeks, effect of rising sea levels, biological zonation, and marsh ecosystem services. The hydroperiod; as the frequency, duration, depth and flux of water across the marsh surface; is a key factor in salt marsh ecology, but remains poorly understood due to lack of data at spatial scales relevant to tracking the spatial movement of water across the marsh. This study examines how hydroperiod, drainage networks, and tidal creek geomorphology on the vegetation at Crab Haul Creek. Crab Haul Creek is the farthest landward tidal basin in North Inlet, a bar-built estuary in South Carolina. This study measures the hydroperiod in the headwaters Crab Haul Creek with normal and near-IR photos from a helium balloon Helikite at 75-100 m altitude. Photos provide detail necessary to resolve the waterline and delineate the hydroperiod during half tidal cycles by capturing the waterline hourly from the headwaters to a piezometer transect 260 meters north. The Helikite is an ideal instrument for local investigations of surface hydrology due to its maneuverability, low cost, ability to remain aloft for extended time over a fixed point, and ability to capture high-resolution images. Photographs taken from aircraft do not provide the detail necessary to determine the waterline on the marsh surface. The near-IR images make the waterline more distinct by increasing the difference between wet and dry ground. In the headwaters of Crab Haul Creek, individual crab burrows are detected by automated image classification and the number of crab burrows and their spatial density is tracked from January-August. Crab burrows are associated with the unvegetated region at the creek head, and we relate their change over time to the propagation of the creek farther into the tidal basin. Plant zonation is influenced by the hydroperiod, but also may be affected by salinity, water table depth, and soil water content. These other factors are all directly affected by the hydroperiod, creating a complex system of feedbacks. Inundation frequencies show a pronounced relationship to zonation. Creek bank height and the hydroperiod have a curvilinear relationship at low bank heights such that small decreases in creek bank height can result in large increases in inundation frequency. Biological zonation is not simply a result of bank height and inundation frequency, other contributing factors include species competition, adaptability, and groundwater flow. Vegetation patterns delineated by a ground-based GPS survey and image classification from the aerial photos show that not all changes in eco-zonation are a direct function of elevation. Some asymmetry across the creek is observed in plant habitat, and eliminating topography (and thereby tidal inundation) as a factor, we attribute the remaining variability to groundwater flow.

White, S. M.; Madsen, E.

2013-12-01

293

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

PubMed

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

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

2013-08-01

294

Evaluation of the ability of two plants for the phytoremediation of Cd in salt marshes  

NASA Astrophysics Data System (ADS)

Several salt marsh plant species have shown to be able to uptake and concentrate metals in their tissues, showing potential for metal phytoremediation. However, studies in controlled conditions, mimicking as much as possible the plants natural environment, are needed to confirm this potential. For the present study, Juncus maritimus and Phragmites australis were collected in an estuary together with the sediment surrounding their roots, put in vessels and maintained in greenhouses under estuarine tidal simulation. After 3 weeks of acclimation, vessels were spiked with two different cadmium concentrations. After 2 months, cadmium was assessed in plant tissues and sediments. Results indicate that both plant species were able to uptake and translocate cadmium into their tissues, contributing also to retain it in rhizosediments and thus reducing the available amount of metal in the environment. Metal was preferentially accumulated in belowground structures, in concentrations not directly proportional to the amount of cadmium present in the sediment. Although no visual toxicity signs were observed, some defence mechanisms were triggered as observed by the changes in carotenoids, lignin, total soluble phenolic compounds and thiolic compounds levels, this response differing between plant species. This work shows that these two salt marsh plants can contribute for the retention of cadmium in salt marshes being useful for the phytostabilization of this metal in estuarine environments.

Nunes da Silva, Marta; Mucha, Ana P.; Rocha, A. Cristina; Silva, Carla; Carli, Carolina; Gomes, Carlos R.; Almeida, C. Marisa R.

2014-03-01

295

Salt marsh vegetation as a carbonyl sulfide (COS) source to the atmosphere  

NASA Astrophysics Data System (ADS)

Carbonyl sulfide (COS) is the most abundant and longest-lived reduced sulfur compound in the atmosphere; changes in its atmospheric concentration could significantly affect global climate and the biogeochemical sulfur cycle. The largest sink of COS in the troposphere is its destruction in plant leaves by the enzymes involved in photosynthesis. In this study, net fluxes of COS were measured from a coastal salt marsh on a subtropical barrier island on the Texas shore of the Gulf of Mexico. We find net emissions from sites with the common salt marsh plant Batis maritima compared to the net uptake from vegetated plots of most previously investigated biomes. The magnitude of the COS production from vegetated plots in this study was twice the emissions of soil-only salt marsh plots. This is the first time that emissions of COS have been found to be significantly enhanced by the presence of vegetation compared to soil alone. COS fluxes exceeded +110 pmol m-2 s-1 for non-inundated plots during daytime hours and were correlated with soil temperature at the depth of 5 cm. Tidal flooding inhibited soil COS exchange; however, we found continued net emissions from emergent B. maritima. This study suggests that emissions of COS resulted from interactions with the plants themselves, which would mean that B. maritima can mediate the production of atmospheric COS.

Whelan, Mary E.; Min, Dong-Ha; Rhew, Robert C.

2013-07-01

296

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

PubMed

Concentrations of Cu and Pb were determined in the roots and shoots of six salt marsh plant species, and in sediment taken from between the roots of the plants, sampled from the lower salt marsh zone at four sites along the Suir Estuary in autumn 1997. Cu was mainly accumulated in the roots of monocotyledonous and dicotyledonous species. Pb was mainly accumulated in the roots of monocotyledons, while dicotyledons tended to accumulate Pb in the shoots. In the case of Aster tripolium there was a clear differentiation in the partitioning of Pb within the plant, between low and high salinity sites. At the low salinity sites, Pb accumulated only in the roots while at the high salinity sites there was a marked translocation to the shoots. The increase in Pb concentrations in roots and shoots of A. tripolium was accompanied by a concomitant decrease in sediment concentrations of Pb. This inverse correlation between sediment and plant concentrations of Pb was also recorded for Spartina spp. and Schoenoplectus tabernaemontani but in the case of these species the roots contained higher concentrations of Pb regardless of salinity levels. These differences in accumulation of Cu and Pb in various salt marsh species, and the influence of salinity on the translocation of Pb in A. tripolium in particular, should be taken into account when using these plants for biomonitoring purposes. PMID:12663206

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

2003-01-01

297

Biogeochemical and hydrological controls on fate and distribution of trace metals in oiled Gulf salt marshes  

NASA Astrophysics Data System (ADS)

On April 20, 2010, the drilling rig Deepwater Horizon exploded in the Gulf of Mexico, resulting in the release of approximately 5 million barrels of crude oil into the environment. Oil and its associated trace metals have been demonstrated to have a detrimental effect on coastal wetland ecosystems. Wetlands are particularly susceptible to oil contamination because they are composed largely of fine-grained sediments, which have a high capacity to adsorb organic matter and metals. The biogeochemical cycling of trace metals can be strongly influenced by microbial activity, specifically those of sulfate- and iron-reducing bacteria. Microbial activity may be enhanced by an increase in amounts of organic matter such as oil. This research incorporates an assessment of levels of trace metals and associated biogeochemical changes from ten coastal marshes in Alabama, Mississippi, and Louisiana. These sampling sites range in their pollution levels from pristine to highly contaminated. A total digestion analysis of wetland sediments shows higher concentrations of certain trace metals (e.g., Ni, Cu, Pb, Zn, Sr, Co, V, Ba, Hg, As) in heavily-oiled areas compared to less-affected and pristine sites. Due to chemical complexation among organic compounds and metals, crude oils often contain elevated levels (up to hundreds of mg/kg) of trace metals At the heavily-oiled Louisiana sites (e.g., Bay Jimmy, Bayou Dulac, Bay Batiste), elevated levels of metals and total organic carbon have been found in sediments down to depths of 30 cm. Clearly the contamination is not limited to shallow sediments and oil, along with various associated metals, may be invading into deeper (pre-industrial) portions of the marsh sediments. Pore-waters extracted from contaminated sediments are characterized by very high levels of reduced sulfur (up to 80 mg/kg), in contrast to fairly low ferrous iron concentrations (<0.02 mg/kg). The influx of oil into the wetlands might provide the initial substrate and carbon source for stimulating sulfate-reducing bacteria. The high sulfur levels, coupled with the low levels of iron, indicate that iron-reducing bacteria are outcompeted by sulfate reducers in oiled salt marshes. Moreover, pore-water pH values show a general increasing trend (ranging from 6.6 to 8.0) with depth, possibly reflecting the combined effects of bacterial sulfate reduction and saltwater intrusion at depth. Despite high levels of trace metals in bulk sediments, concentrations of trace metals dissolved in pore-waters are generally low. It is very likely that high organic matter content and bacterially-mediated sulfate reduction promote metal retention through the formation of sulfide solids. Framboidal pyrites, as well as other sulfides, have been identified, and are currently undergoing XRD, SEM, and EDAX analyses. Continued research is needed to monitor possible re-mobilization of trace metals in changing redox and biogeochemical conditions.

Keevan, J.; Natter, M.; Lee, M.; Keimowitz, A.; Okeke, B.; Savrda, C.; Saunders, J.

2011-12-01

298

Alterations to Tidal Marsh Carbon Cycling and Greenhouse Gas Exchange in Response to Sea-Level and Salt-Water Intrusion (Invited)  

NASA Astrophysics Data System (ADS)

Tidal marshes are highly productive ecosystems with the potential to sequester large amounts of carbon. However, tidal wetlands may be sources of the powerful greenhouse gases (GHGs) methane (CH4) and nitrous oxide (N2O), which are produced via microbial metabolic processes. As global climate changes it is increasingly important to understand the factors that control ecosystem productivity, GHG fluxes, and potential feedbacks between global change factors, C cycling, and marsh resilience to sea-level rise (SLR). Field measurements were undertaken to quantify rates of GHG (CO2 and CH4) exchange rates, plant biomass, microbial sulfate reduction and methanogenesis rates, and soil biogeochemistry at three tidal wetland sites along the salinity gradient in the Delaware River Estuary over four years. Despite similar plant productivity between marsh types, differences in microbial processes largely determined the GHG source/sink status of the wetland types. Mesohaline salt-marshes consistently sequestered C (~300 g C m-2 yr-1), and due to negligible CH4 release, were also a GHG sink (~1350 g CO2-eq m-2 yr-1). In contrast, the TFM sequestered C (~350 g C m-2 yr-1) but because of appreciable release of CH4 from freshwater wetland soils was GHG neutral. The oligohaline marsh site experienced significant seasonal salt-water intrusion (SWI) in the late summer during the four year study period, resulting in major alterations to marsh C cycling. The oligohaline marsh did not sequester C (loss of ~45 g C m-2 yr-1) in part due to surprisingly high rates of CH4 release (190 g CH4 m-2 yr-1). The oligohaline marsh undergoing SWI was therefore a significant source of GHG to the atmosphere (~4000 g CO2-eq m-2 yr-1). These results indicate that SWI alters C cycling and GHG exchange in marsh systems, and may accelerate the decomposition of organic matter limiting the ability of marshes to accrete material and keep pace with SLR. The impacts of SWI on TFM soil C cycling were further investigated in a one year laboratory experiment. Microbial organic matter mineralization to CO2 increased following simulated SWI. This was linked to greater availability of sulfate (SO42-) and higher rates of microbial sulfate reduction, resulting in significantly greater flux of CO2 from TFM soils. Rates of CH4 release were also significantly greater from soils following SWI, and microbial acetoclastic methanogensis was not inhibited by the introduction of salt-water, supporting findings from the field measurements. Higher rates of microbial organic matter mineralization via both sulfate reduction and methanogenesis resulted in declining soil organic matter following SWI. A multi-year field manipulation utilizing modified marsh ';organs' to examine the interactive effects of both SWI and SLR indicated that, while N2O emissions decreased with flooding (-0.3 g m-2 yr-1 cm-1), rates of CH4 flux increased with flooding (2.3 g m-2 yr-1 cm-1) corresponding to measured increases in microbial methanogenesis and resulting in a net increase in GHG release. There were complex interactions between changes in plant production and microbial organic matter decomposition with both SLR and SWI, and TFMs experiencing both SLR and SWI simultaneously had reduced C sequestration and increased GHG release. SLR and SWI therefore limit the vertical accretion potential of TFMs, put TFMs at risk of permanent submergence, and produce a feedback to atmospheric GHG concentrations.

Weston, N. B.

2013-12-01

299

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

PubMed

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

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

2008-03-01

300

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

301

Mercury accumulation in largemouth bass (Micropterus salmoides Lacépède) within marsh ecosystems of the Florida Everglades, USA.  

PubMed

This study evaluates factors, particularly water quality related, that may influence mercury (Hg) bioaccumulation in largemouth bass (LMB, Micropterus salmoides Lacépède) within the Everglades marshes of South Florida. The investigation is an empirical analysis of ambient data from both long-term fish monitoring and marsh water quality monitoring sites across the Everglades Protection Area. Previous Hg studies of Everglade's marsh biota have focused on the role that sulfate plays in Hg bioaccumulation. While sulfate can be important under some environmental conditions, this empirical analysis in Everglades marshes showed that sulfate has little association with Hg concentrations in LMB. It is suggested that other water quality variables including water pH, alkalinity and specific conductance may have as much or more influence in the accumulation of Hg in LMB. Furthermore, tissue Hg concentration normalized to body-weight and age-specific growth rates were significantly correlated with Water Conservation Area (WCA)-1, WCA-2 and Everglades National Park (ENP) but not WCA-3. However, body condition was correlated negatively with Hg concentration only within WCA-2, WCA-3 and ENP; the relationship was not significant within WCA-1. This disparity between Hg concentration and body condition could be attributed to ecological effects including water quality and quantity conditions within each compartment of the system that are significant driving forces for biota abundance, trophic structure and distribution within the Everglades ecosystem. While water quality and quantity are important, trophic position of LMB has the potential to influence Hg accumulation dynamics. In spite of documented biogeochemical linkages to Hg accumulation, this empirical analysis did not demonstrate enough quantitative interaction to be useful for Hg management in the Everglades ecosystem. PMID:25336046

Julian, Paul; Gu, Binhe

2014-10-22

302

The weathering of oil after the Deepwater Horizon oil spill: insights from the chemical composition of the oil from the sea surface, salt marshes and sediments  

NASA Astrophysics Data System (ADS)

The oil released during the Deepwater Horizon (DWH) oil spill may have both short- and long-time impacts on the northern Gulf of Mexico ecosystems. An understanding of how the composition and concentration of the oil are altered by weathering, including chemical, physical and biological processes, is needed to evaluate the oil toxicity and impact on the ecosystem in the northern Gulf of Mexico. This study examined petroleum hydrocarbons in oil mousse collected from the sea surface and salt marshes, and in oil deposited in sediments adjacent to the wellhead after the DWH oil spill. Oil mousses were collected at two stations (OSS and CT, located 130 and 85 km away from the wellhead, respectively) in May 2010, and two sediment samples from stations SG and SC, within 6 km of the wellhead, in May 2011. We also collected oil mousse from salt marshes at Marsh Point (MP), Mississippi, 186 km away from the wellhead in July 2010. In these samples, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, BTEX (collective name of benzene, toluene, ethylbenzene and p-, m-, and o-xylenes), C3-benzenes and trace metals were measured to examine how the oil was altered chemically. The chemical analysis indicates that the oil mousses underwent different degrees of weathering with the pattern of OSS < CT < MP. This pattern is consistent with the projected oil mousse movement from the accident site to salt marshes. Also, the contents of trace metals Al, V, Cr, Fe, Mn, Ni, Co, Cu, As and Pb in the oil mousse generally increased along the way to the salt marshes, indicating that these trace metals were perhaps aggregated into the oil mousse during the transport. Petroleum hydrocarbon data reveal that the oil deposited in sediments underwent only light to moderate degradation one year after the DWH oil spill, as supported by the presence of short-chained n-alkanes (C10-C 15), BTEX and C 3-benzenes. The weathering of oil in sediment may result from biological degradation and dissolution, evidenced by the preferential loss of mid-chained n-alkanes C16-C 27, lower ratios of n-C 17/Pr and n-C 18/Ph , and preferential loss of PAHs relative to alkylated PAHs.

Liu, Zhanfei; Liu, Jiqing; Zhu, Qingzhi; Wu, Wei

2012-09-01

303

Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay, France)  

NASA Astrophysics Data System (ADS)

At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt marshes) of Mont Saint-Michel Bay. These and other comparable shallow marine coastal waters, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has been paid to the value of tidal salt marshes for fishes. Between March 1996 and April 1999, 120 tides were sampled in a tidal creek. A total of 31 species were caught. This community was largely dominated by mullets ( Liza ramada represent 87% of the total biomass) and sand gobies ( Pomatoschistus minutus and P. lozanoi represent 82% of the total numbers). These species and also Gasterosteus aculeatus , Syngnathus rostellatus, Dicentrarchus labrax, Mugil spp., Liza aurata and Sprattus sprattus were the most frequent species (>50% of monthly frequency of occurrence). In Europe, salt marshes and their creeks are flooded only during high spring tides. So, fishes only invade this environment during short immersion periods, and no species can be considered as marsh resident. But, the salt marsh was colonized by fish every time the tide reached the creek, and during the short time of flood, dominant fishes fed actively and exploited the high productivity. Nevertheless, this study shows that there is little interannual variation in the fish community and there are three ' seasons ' in the fish fauna of the marsh. Marine straggler and marine estuarine dependent species colonize marshes between spring (recruitment period in the bay) and autumn before returning into deeper adjacent waters. Estuarine fishes are present all year round with maximum abundances in the end of summer. The presence of fishes confirms that this kind of wetland plays an important trophic and nursery role for these species. Differences in densities and stages distribution of these species into Mont Saint-Michel systems (tidal mudflats, estuaries and tidal salt marshes) can reduce the trophic competition.

Laffaille, P.; Feunteun, E.; Lefeuvre, J.-C.

2000-10-01

304

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

305

Salt marsh retreat induced by wind waves: experiments, field and modeling  

NASA Astrophysics Data System (ADS)

Edge erosion of salt marshes due to surface waves and tide forcing is likely the chief mechanism that models marsh boundaries and by which salt marshes in worldwide areas are being lost. To address this problem, an experimental investigation in a laboratory flume and field measurements collected in the lagoon of Venice were conducted to understand the main processes controlling marsh edge retreat with a focus on the erosion mechanisms caused by the impact of wind waves in the case of various tidal levels. A physical model reproducing a salt marsh bank was built inside a long wave current flume where random surface waves have been generated according to a given wave spectrum. The physical model was constructed with the original soil of salt marshes from the Venice Lagoon, while the wave climate was reproduced according to field measurements. In order to reveal the effect of vegetation on bank stability, two identical banks were built but for the inclusion of halophytic plants. A first set of experiments was conducted reproducing only tidal waves, a second set with wind waves superimposed to the tide. A third set o f experiments were aimed to investigate the dynamic impact and transmission of the waves on and within the bank. The following quantities were collected during the experiments: water content and pore water pressure inside the bank, water levels and velocities at various distances from the bank, dynamic pressures on the bank edge surface and internal pressure fluctuations due to wave impact. Bank geometry profile and bottom topography at different times have also been collected to characterize the erosion rate with time and the evolution of bank retreat. Two types of mass failures were observed during the experiments: slides and toppling failures. The latter were most frequently observed failures, consisting in the toppling of blocks and were often the consequence of the presence of deep tension cracks. In most cases the impact of wind waves caused the overturning of the block. In both the unvegetated and vegetated experiments, mass failures occurred in the first part of the experiment whereas the remaining part was characterized by particle by particle erosion. Effect of vegetation lead to a delay in block failures due the presence of roots, although the total eroded volume differed slightly between the two scenarios. The field measurements were aimed at quantifying the erosion characteristics of marsh soil and the wave climate close to the bank edge during a moderate wind event. Several pressure transducers installed 0.15 m above the bed and adequately spaced were used to collect wave height and wave direction with respect to the edge of the marsh. Then, on the base of experimental and field evidence, a new toppling model is proposed and test against laboratory data: a block of cohesive material at incipient failing condition is attached to the underlying layer and identified by the presence of tension crack; it behaves as a dynamical system subjected to several forces, until the tensile strength of the material is exceed. Test of the model showed its capability at reproducing the failure process and it highlighted which are the most crucial conditions in promoting the failure of a bank edge subjected to wave attack and tide forcing.

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

2013-12-01

306

Primary production of edaphic algal communities in a Mississippi salt marsh  

SciTech Connect

Primary production rates of edaphic algae associated with the sediments beneath four monospecific canopies of vascular plants were determined over an annual cycle in a Mississippi salt marsh. The edaphic algal flora was dominated by small, motile pennate diatoms. Algal production (as measured by /sup 14/C uptake) was generally highest in spring-early summer and lowest in fall. Hourly rates ranged from a low of 1.4 mg C/m/sup 2/ in Juncus roemerianus Scheele to a high of 163 mg C/m/sup 2/ beneath the Scirpus olneyi Gray canopy. Stepwise multiple regressions identified a soil moisture index and chlorophyll a as the best environmental predictors of hourly production; light energy reaching the marsh surface and sediment and air temperature proved of little value. Adding the relative abundances of 33 diatom taxa to the set of independent variables only slightly increased R/sup 2/; however, virtually all variables selected were diatom taxa. R/sup 2/ was only 0.38 for the Spartina alterniflora Loisel. habitat but ranged from 0.70 to 0.87 for the remaining three vascular plant zones. Annual rates of algal production (g C/m/sup 2/) were estimated as follows: Juncus (28), Spartina (57), Distichlis spicata (L.) Greene (88), and Scirpus (151). The ratio of annual edaphic algal production to vascular plant net aerial production (EAP/VPP) was 10-12% for the first three habitats and 61% for Scirpus. Chlorophyll a concentrations, annual algal production rates, and EAP/VPP values were comparable to those determined in Texas, Delaware, and Massachusetts salt marshes but lower than those reported for Georgia and particularly California marshes.

Sullivan, M.J.; Moncreiff, C.A.

1988-03-01

307

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

308

A multi-proxy study of sedimentary humic substances in the salt marsh of the Changjiang Estuary, China  

NASA Astrophysics Data System (ADS)

To better understand the origin, composition, and reactivity of sedimentary humic substances (HSs) in salt marshes in the Changjiang Estuary, HS samples were isolated from a sediment core that was collected from the Eastern Chongming salt marsh. Chemical and spectroscopic methods were used to analyze the features of these HSs. The results indicate that the studied HSs in the salt marsh sediments are mainly terrestrial-derived and that the sedimentary organic matter (SOM) in the top layer may contain more organic matter from marine sources and/or autochthonous materials due to the dramatic decreasing of the sediment supply as a result of damming. The degradation of labile carbohydrates and proteins and the preservation of refractory lignin components dominate the early diagenetic reactions of SOM in the salt marsh area. The average contents of the carboxylic groups in FAs and HAs are 11.64 ± 1.08 and 7.13 ± 0.16 meq/gC, and those of phenolic groups are 1.95 ± 0.13 and 2.40 ± 0.44 meq/gC, respectively. The content of carboxylic groups increased with increasing depth, while there were no obvious changes in the content of phenolic groups. The average concentration of total proton-binding sites is approximately 12.5 ?mol/g sediment for the studied HSs. These values may provide insight into the migration and fate of HS-bound contaminants in sediments and the overlying sea water in the salt marsh areas of the Changjiang Estuary.

Zhang, Yaoling; Du, Jinzhou; Zhao, Xin; Wu, Wangsuo; Peng, Bo; Zhang, Jing

2014-12-01

309

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

310

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

311

Use of airborne polarimetric SAR, optical and elevation data for mapping and monitoring of salt marsh vegetation habitats  

NASA Astrophysics Data System (ADS)

Within the Copernicus programme there is much interest in the ability of remote sensing technology to deliver operational solutions to many areas of life including environmental management. This paper describes research focused on the application of Earth Observation for Integrated Coastal Zone Management. The main topic of this research is to explore to which extent salt marsh vegetation habitats can be identified from polarimetric SAR remotely sensed data. Multi-frequency, multi-polarimetric SAR images from airborne (S- and X-Band quad-polarimetric from the Astrium airborne SAR Demonstrator) is used to examine salt marsh habitat classification potential in the Llanrhidian salt marshes in South Wales, UK. This is achieved by (1) using both supervised and unsupervised classification routines, using several polarimetric SAR data layers as backscatter intensity, band ratios and polarimetric decomposition products, and by (2) statistical analysis by regression of these different SAR data layers and botanical parameters acquired from recent ecological fieldwork.

van Beijma, Sybrand; Comber, Alexis; Lamb, Alistair

2014-10-01

312

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

313

Effects of Natural and Anthropogenic Change on Habitat Use and Movement of Endangered Salt Marsh Harvest Mice  

PubMed Central

The northern salt marsh harvest mouse (Reithrodontomys raviventris halicoetes) is an endangered species endemic to the San Francisco Bay Estuary. Using a conservation behavior perspective, we examined how salt marsh harvest mice cope with both natural (daily tidal fluctuations) and anthropogenic (modification of tidal regime) changes in natural tidal wetlands and human-created diked wetlands, and investigated the role of behavioral flexibility in utilizing a human-created environment in the Suisun Marsh. We used radio telemetry to determine refuge use at high tide, space use, and movement rates to investigate possible differences in movement behavior in tidal versus diked wetlands. We found that the vast majority of the time salt marsh harvest mice remain in vegetation above the water during high tides. We also found no difference in space used by mice during high tide as compared to before or after high tide in either tidal or diked wetlands. We found no detectable difference in diurnal or nocturnal movement rates in tidal wetlands. However, we did find that diurnal movement rates for mice in diked wetlands were lower than nocturnal movement rates, especially during the new moon. This change in movement behavior in a relatively novel human-created habitat indicates that behavioral flexibility may facilitate the use of human-created environments by salt marsh harvest mice. PMID:25310800

Smith, Katherine R.; Barthman-Thompson, Laureen; Gould, William R.; Mabry, Karen E.

2014-01-01

314

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

PubMed Central

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

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

2013-01-01

315

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

E-print Network

isotopes in a groundwater-dominated salt marsh estuary Matthew A. Charette1 Department of Marine Chemistry 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

316

Vegetation succession and herbivory in a salt marsh: changes induced by sea level rise and silt deposition along an elevational gradient  

Microsoft Academic Search

1 The relationships between soil development, vertical vegetation zonation, vegetation succession and herbivory by Brent geese, Branta bernicla, were studied in a coastal salt marsh. We were able to analyse up to 100 years of salt marsh development by comparing sites where vegetation succession had progressed for-various periods of time. These data were related to a continuous daily record of

H. Olff; J. De Leeuw; J. P. Bakker; Platerink J. R; Van Wijnen J. H; W. De Munck

1997-01-01

317

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

Microsoft Academic Search

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

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

1998-01-01

318

Schalles, J.F., C.M. Hladik, A.A. Lynes, and S.C. Pennings. 2013. Landscape estimates of habitat types, plant biomass, and invertebrate densities in a Georgia salt marsh.  

E-print Network

of habitat types, plant biomass, and invertebrate densities in a Georgia salt marsh. Oceanography 26 types, plant Biomass, and invertebrate Densities in a georgia Salt marsh By J O h N F. S c h a l l eBStract. Salt marshes often contain remarkable spatial heterogeneity at multiple scales across the landscape

Pennings, Steven C.

319

Effects of flooding and warming on soil organic matter mineralization in Avicennia germinans mangrove forests and Juncus roemerianus salt marshes  

NASA Astrophysics Data System (ADS)

Under a changing climate, coastal wetlands experience sea level rise, warming, and vegetation change, all of which may influence organic matter mineralization. In coastal wetlands of subtropical west-central Florida (USA), we investigated how soil carbon (C) and nitrogen (N) mineralization respond to soil water, temperature, and ecosystem type (Avicennia germinans mangrove forest vs. Juncus roemerianus salt marsh). We evaluated how soil respiration and mineral N concentration varied along a soil moisture gradient, and whether these relationships differed between ecosystem types. Then, we manipulated soils in a 28-d laboratory incubation to evaluate how potentially mineralizable C and N respond to temperature (23 vs. 27 °C), soil hydroperiod (inundated 4 vs. 20 h/d), and soil source. Soil saturation and inundation suppressed short-term (minutes to weeks) C mineralization from near-surface soils. Soil CO2 efflux declined by 65% as soil moisture increased from 75% to 85%, and potentially mineralizable C was 18% lower with a 20-h hydroperiod than with a 4-h hydroperiod. Organic C quality appears to be greater in A. germinans than in J. roemerianus soils, as A. germinans soils had higher field CO2 efflux rates and greater mineralizable C:N (despite lower total C:N). Increasing incubation temperature from 23 to 27 °C elevated potentially mineralizable C by 40%, indicating that two symptoms of climate change (increased inundation from sea level rise, and warming) may have opposing effects on soil C mineralization. Temperature sensitivity of C mineralization was high for long-hydroperiod soils, however, suggesting that protection of soil organic matter (SOM) due to prolonged inundation will be undermined by warming. Potentially mineralizable N was greater in J. roemerianus soils, although in situ mineral N was not different between ecosystems, instead correlating positively with SOM. These results indicate that models forecasting soil elevation responses to climate change might include inundation effects on mineralization rates.

Lewis, David Bruce; Brown, Jewel A.; Jimenez, Kristine L.

2014-02-01

320

Seasonal variability of diazotroph assemblages associated with the rhizosphere of the salt marsh cordgrass, Spartina alterniflora.  

PubMed

Nitrogen fixation is the primary N source in the highly productive but N-limited North Inlet, SC, USA salt marsh system. The diverse assemblages of nitrogen-fixing (diazotrophic) bacteria associated with the rhizospheres of the short and tall growth forms of Spartina alterniflora were analyzed at two sites, Crab Haul Creek and Goat Island, which are in different tidal creek drainage systems in this marsh. The sites differed in proximity to the main channel for tidal intrusion and in several edaphic parameters. We hypothesized that either the differing abiotic environmental regimes of the two sites or the variation due to seasonal effects result in differences in the diazotroph assemblage. Rhizosphere samples were collected seasonally during 1999 and 2000. DNA was purified and nifH amplified for denaturing gradient gel electrophoresis (DGGE) analysis of diazotroph assemblage composition. Principal components analysis was used to analyze the binary DGGE band position data. Season strongly influenced assemblage composition and biplots were used to identify bands that significantly affected the seasonal and site-specific clustering. The types of organisms that were most responsive to seasonal or site variability were identified on the basis of DGGE band sequences. Seasonally responsive members of the anaerobic diazotrophs were detected during the winter and postsenescence conditions and may have been responsible for elevated pore water sulfide concentrations. Sequences from a diverse assemblage of Gammaproteobacteria were predominant during growth periods of S. alterniflora. Abiotic environmental parameters strongly influenced both the S. alterniflora and the diazotrophic bacterial assemblages associated with this keystone salt marsh plant species. PMID:19626265

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

2010-02-01

321

Potential of phytoremediation for the removal of petroleum hydrocarbons in contaminated salt marsh sediments.  

PubMed

Degradation of petroleum hydrocarbons in colonized and un-colonized sediments by salt marsh plants Juncus maritimus and Phragmites australis collected in a temperate estuary was investigated during a 5-month greenhouse experiment. The efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms was tested in comparison with hydrocarbon natural attenuation in un-colonized and with rhizoremediation in colonized sediments. Hydrocarbon degrading microorganisms and root biomass were assessed as well as hydrocarbon degradation levels. During the study, hydrocarbon degradation in un-colonized sediments was negligible regardless of treatments. Rhizoremediation proved to be an effective strategy for hydrocarbon removal, yielding high rates in most experiments. However, BS treatments showed a negative effect on the J. maritimus potential for hydrocarbon degradation by decreasing the root system development that lead to lower degradation rates. Although both plants and their associated microorganisms presented a potential for rhizoremediation of petroleum hydrocarbons in contaminated salt marsh sediments, results highlighted that nutrient requirements may be distinct among plant species, which should be accounted for when designing cleanup strategies. PMID:24584003

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

2014-05-01

322

Physiological Diversity of the Rhizosphere Diazotroph Assemblages of Selected Salt Marsh Grasses  

PubMed Central

Rhizosphere diazotroph assemblages of salt marsh grasses are thought to be influenced by host plant species and by a number of porewater geochemical parameters. Several geochemical variables can adversely affect plant productivity and spatial distributions, resulting in strong zonation of plant species and growth forms. This geochemically induced stress may also influence the species compositions and distributions of rhizosphere diazotroph assemblages, but little is currently known about these organisms. The diversity and key physiological features of culturable, O2-tolerant rhizosphere diazotrophs associated with the tall and short growth forms of Spartina alterniflora and with Juncus roemerianus were examined. A total of 339 gram-negative strains were isolated by a root stab culture approach and morphologically and physiologically characterized by using API and BIOLOG tests. Eighty-six distinct groups composed of physiologically similar strains were identified. Of these groups, 72% were shown to be capable of N2 fixation through molecular analyses, and a representative strain was chosen from each diazotroph group for further characterization. Cluster and principal-components analysis of BIOLOG data allowed the designation of physiologically distinct strain groupings. Most of these groups were dominated by strains that were not identifiable to species on the basis of API or BIOLOG testing. Representatives of several families including the Enterobacteriaceae, Vibrionaceae, Azotobacteraceae, Spirillaceae, Pseudomonadaceae, and Rhizobiaceae were recovered, as well as strains with no clear taxonomic affiliations. This study identifies numerous potentially important physiological groups of the salt marsh diazotroph assemblage. PMID:9797277

Bagwell, Christopher E.; Piceno, Yvette M.; Ashburne-Lucas, Amy; Lovell, Charles R.

1998-01-01

323

Comparison of Bulk and Compound-Specific Carbon Isotope Analyses and Determination of Carbon Sources to Salt Marsh Sediments Using n-Alkane Distributions (Maine, USA)  

NASA Astrophysics Data System (ADS)

Sources of sedimentary organic matter to a Morse River, Maine (USA) salt marsh over the last 3390+/-60 RCYBP are determined using distribution patterns of n-alkanes as well as bulk and compound-specific carbon isotopic analysis. Marsh foraminiferal counts indicate the ubiquitous presence of zone 1B deposits, suggesting that the deposits were laid down ~0.2 to 0.5m above mean high water. Distributions of n-alkanes show a primary contribution from higher plants, confirmed by an average ACL value of 27.5 for the core sediments and CPI values above 3. Many sample depths have a maximum abundance at the C25 alkane. Ten low marsh, high marsh, and higher-high marsh plant species common to Maine salt marshes were sampled, including Spartina alterniflora, Spartina patens, Juncus gerardi and Solidago sempervirens. The ACL value for the average of the 10 marsh species is 29.1. Salicornia europa, usually not considered to be a dominant species in Maine marshes, has a similar n-alkane distribution to many of the salt marsh sediments, suggesting that it is an important source to the biomass of the marsh through time. Bacterial degradation or algal inputs to the marsh sediments appear to be minor. Compound specific carbon isotopic analyses of the C27 alkanes are, on average, 7.2ppt. depleted relative to bulk values, but the two records are strongly correlated (R2 = 0.87), suggesting that marsh plants are "swamping" the bulk carbon isotopic signal. The apparent abundance of a subordinate (though common) salt marsh plant species (Salicornia europa) within our core underscores the importance of using caution when applying mixing models of relatively few plant species to marsh sediments.

Tanner, B. R.; Uhle, M. E.; Kelley, J. T.; Mora, C. I.

2005-12-01

324

Invasion of tamarisk (Tamarix spp.) in a southern California salt marsh  

Technology Transfer Automated Retrieval System (TEKTRAN)

Exotic plants have been demonstrated to be one of the greatest threats to wetlands, as they are capable of altering ecosystem-wide physical and biological properties. One of the most problematic invaders in the western United States has been salt cedar, Tamarix sp., and the impacts of this species i...

325

Visualizing changes in the community structure of sulfur cycling bacteria in nitrogen enriched salt marsh sediments  

E-print Network

Visualizing changes in the community structure of sulfur cycling bacteria in nitrogen enriched salt. Nitrogen loading could perturb the sulfur cycle through the introduction of more below ground biomass, and in these ecosystems over 50% of carbon mineralized is due to sulfate reduction. Anthropogenic inputs of nitrogen

Vallino, Joseph J.

326

Seed dispersal and seedling emergence in a created and a natural salt marsh on the Gulf of Mexico coast in Southwest Louisiana, U.S.A  

USGS Publications Warehouse

Early regeneration dynamics related to seed dispersal and seedling emergence can contribute to differences in species composition among a created and a natural salt marsh. The objectives of this study were to determine (1) whether aquatic and aerial seed dispersal differed in low and high elevations within a created marsh and a natural marsh and (2) whether seedling emergence was influenced by marsh, the presence of openings in the vegetation, and seed availability along the northern Gulf of Mexico coast. Aerial seed traps captured a greater quantity of seeds than aquatic traps. Several factors influenced aquatic and aerial seed dispersal in a created and a natural salt marsh, including distance from the marsh edge, cover of existing vegetation, and water depth. The natural marsh had a high seed density of Spartina alterniflora and Distichlis spicata, the low-elevation created marsh had a high seed density of S. alterniflora, and the high-elevation created marsh had a high seed density of Aster subulatus and Iva frutescens. The presence of adult plants and water depth above the marsh surface influenced seed density. In the natural marsh, openings in vegetation increased seedling emergence for all species, whereas in the low-elevation created marsh, S. alterniflora had higher seedling density under a canopy of vegetation. According to the early regeneration dynamics, the future vegetation in areas of the low-elevation created marsh may become similar to that in the natural marsh. In the high-elevation created marsh, vegetation may be upland fringe habitat dominated by high-elevation marsh shrubs and annual herbaceous species. ?? 2009 Society for Ecological Restoration International.

Elsey-Quirk, T.; Middleton, B.A.; Proffitt, C.E.

2009-01-01

327

Free-living plathelminthes in sheep-grazed and ungrazed supralittoral salt marshes of the North Sea: Abundance, biomass, and their significance in food chains  

NASA Astrophysics Data System (ADS)

The supralittoral salt marshes of the North Sea are marked by high halophyte primary productivity. The environmental factors are strongly fluctuating. Despite these features the metazoan meiofaunal abundance is equal to that found in other littoral habitats. On average 1250 marine metazoans are found per 10 cm 2 in ungrazed and 770 per 10 cm 2 in sheep-grazed supralittoral salt marshes. Nematoda dominate in numerical abundance, Oligochaeta in biomass. Plathelminthes account for 15% of marine metazoans in ungrazed and 5% in grazed salt marshes. Total plathelminth abundance increases with halophyte density, whereas the abundance of diatom-feeding Plathelminthes decreases. In ungrazed marshes on average 104 Plathelminthes are found per 10 cm 2, accounting for a biomass of 0.65 g DW·m -2. In sheep-grazed marshes the average abundance is only 32 individuals per 10 cm 2, accounting for a biomass of 0.1 g DW·m -2. Average individual weight is 3.2 ?g DW or 2.5 ?g AFDW. In grazed salt marshes, 30% of plathelminthes feed on diatoms, 66% are predators, and 4% feed on bacteria (gut analysis). In ungrazed salt marshes only 3% are diatom-feeders, and 90% are predators feeding on Nematoda, Copepoda, Oligochaeta, and smaller Plathelminthes. Presumably plathelminthes are top predators on the salt marsh meiofauna.

Armonies, W.

328

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

329

Aquatic insects of New York salt marsh associated with mosquito larval habitat and their potential utility as bioindicators.  

PubMed

The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonomic survey of salt marsh aquatic insects on Long Island, New York, USA and to evaluate their utility for non-target pesticide impacts and environmental biomonitoring. A total of 18 species from 11 families and five orders were collected repeatedly during the five month study period. Diptera was the most diverse order with nine species from four families, followed by Coleoptera with four species from two families, Heteroptera with three species from three families, then Odonata and the hexapod Collembola with one species each. Water boatmen, Trichocorixa verticalis Fieber (Heteroptera: Corixidae) and a shore fly, Ephydra subopaca Loew (Diptera: Ephydridae), were the two most commonly encountered species. An additional six species; Anurida maritima Guérin-Méneville (Collembola: Neanuridae), Mesovelia mulsanti White (Heteroptera: Mesovelidae), Enochrus hamiltoni Horn (Coleoptera: Hydrophilidae), Tropisternus quadristriatus Horn (Coleoptera: Hydrophilidae), Dasyhelea pseudocincta Waugh and Wirth (Diptera: Ceratopogonidae), and Brachydeutera argentata Walker (Diptera: Ephydridae), were found regularly. Together with the less common Erythrodiplax berenice Drury (Odonata: Libellulidae), these nine species were identified as the most suitable candidates for pesticide and environmental impact monitoring due to abundance, position in the food chain, and extended seasonal occurrence. This study represents a first step towards developing an insect-based index of biological integrity for salt marsh health assessment. PMID:22957707

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

2011-01-01

330

Salt tolerance in a Juncus roemerianus brackish marsh: Spatial variations in plant water relations  

Microsoft Academic Search

Halophytes residing in tidal marshes are often subjected to intense and varying environmental demands. These variations may occur in a matter of hours, with tidal-induced changes in hydrology and soil chemistry (including soil oxygen status, redox potentials, and salinity). Juncus roemerianus has been shown to occupy three dissimilar marsh zones, including lower marsh with minimally diluted saline waters, mid-marsh which

B. W. Touchette

2006-01-01

331

Long-term effects of an oil spill on populations of the salt-marsh crab Uca pugnax  

Microsoft Academic Search

A spill of fuel oil at West Falmouth, Massachusetts, in 1969, contaminated contiguous salt marshes with up to 6000 micrograms of oil per gram (ppM) of wet mud and affected local populations of Uca pugnax. Directly related to high-sediment oil content were reduced crab density, reduced ratio of females to males, reduced juvenile settlement, heavy overwinter mortality, incorporation of oil

C. T. Krebs; K. A. Burns

1977-01-01

332

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

EPA Science Inventory

We examined the vascular plant species richness and the extent, density, and height of Spartina species of ten Narragansett Bay, Rhode Island (United States) fringe salt marshes which had a wide range of residential land development N-loadings associated with their watersheds. Si...

333

Can Thin-lipped Mullet Directly Exploit the Primary and Detritic Production of European Macrotidal Salt Marshes?  

NASA Astrophysics Data System (ADS)

Juveniles and adults (>100 mm) of Liza ramada colonize macrotidal salt marsh creeks of Mont Saint-Michel bay (France) between March and November, during spring tide floods (43% of the tides) and return to coastal waters during the ebb. This fish species actively feeds during its short stay in the creek (from 1 to 2 h). On average, each fish swallows sediment including living and inert organic matter, which amounts to 8% of its fresh body weight. Their diet is dominated by small benthic items (especially diatoms and salt marsh plant detritus), that correspond to the primary and detritic production of this macrotidal salt marsh creek. Despite very short submersion periods, mullets filter and ingest large quantities of sediment and concentrated organic matter (on average organic matter in stomach content is 31%) produced by these coastal wetlands. European salt marshes are thus shown to act as trophic areas for mullets, which are well adapted to this constraining habitat which is only flooded for short periods during spring tides.

Laffaille, P.; Feunteun, E.; Lefebvre, C.; Radureau, A.; Sagan, G.; Lefeuvre, J.-C.

2002-04-01

334

Role of different salt marsh plants on metal retention in an urban estuary (Lima estuary, NW Portugal)  

Microsoft Academic Search

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

C. M. R. Almeida; Ana P. Mucha; M. Teresa Vasconcelos

2011-01-01

335

LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination  

Microsoft Academic Search

This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants

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

2010-01-01

336

Native plant restoration combats environmental change: development of carbon and nitrogen sequestration capacity using small cordgrass in European salt marshes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Restoration of salt marshes is critical in the context of climate change and eutrophication of coastal waters, because their vegetation and sediments may act as carbon and nitrogen sinks. Our primary objectives were to quantify carbon (C) and nitrogen (N) stocks and sequestration rates in restored m...

337

GEOGRAPHIC DISTRIBUTION AND DIVERSITY IN CLAVICEPS PURPUREA (FR.) TUL FROM SALT MARSH HABITATS AND CHARACTERIZATION OF PACIFIC COAST POPULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Claviceps purpurea that is specific to grasses in salt marsh habitats (G3) has previously been identified on Spartina spp. in two locations: New Jersey, USA and Southern England. We have identified G3 in 11 distinct populations including Western Europe, South America, and along the Atlantic and Paci...

338

FATE OF FENTHION IN SALT-MARSH ENVIRONMENTS: 1. FACTORS AFFECTING BIOTIC AND ABIOTIC DEGRADATION RATES IN WATER AND SEDIMENT  

EPA Science Inventory

Fenthion (Baytex), an organophosphate insecticide, is frequently applied to salt-marsh environments to control mosquitoes. hake-flask tests were used to study rates of abiotic and biotic degradation of fenthion and the environmental parameters that affect these rates. Water or wa...

339

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

340

Ecological effects of climate change on salt marsh wildlife: a case study from a highly urbanized estuary  

USGS Publications Warehouse

Coastal areas are high-risk zones subject to the impacts of global climate change, with significant increases in the frequencies of extreme weather and storm events, and sea-level rise forecast by 2100. These physical processes are expected to alter estuaries, resulting in loss of intertidal wetlands and their component wildlife species. In particular, impacts to salt marshes and their wildlife will vary both temporally and spatially and may be irreversible and severe. Synergistic effects caused by combining stressors with anthropogenic land-use patterns could create areas of significant biodiversity loss and extinction, especially in urbanized estuaries that are already heavily degraded. In this paper, we discuss current ideas, challenges, and concerns regarding the maintenance of salt marshes and their resident wildlife in light of future climate conditions. We suggest that many salt marsh habitats are already impaired and are located where upslope transgression is restricted, resulting in reduction and loss of these habitats in the future. In addition, we conclude that increased inundation frequency and water depth will have negative impacts on the demography of small or isolated wildlife meta-populations as well as their community interactions. We illustrate our points with a case study on the Pacific Coast of North America at San Pablo Bay National Wildlife Refuge in California, an area that supports endangered wildlife species reliant on salt marshes for all aspects of their life histories.

Thorne, Karen M.; Takekawa, John Y.; Elliott-Fisk, Deborah L.

2012-01-01

341

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

342

Species-specific patterns of litter processing by terrestrial isopods (Isopoda: Oniscidea) in high intertidal salt marshes and coastal forests  

Microsoft Academic Search

Summary 1. The species-specificity of litter processing by three species of isopods at the interface between salt marsh and coastal forest habitats in the south-eastern United States was examined. 2. To quantify isopod performance, measurements were taken of feeding, digestion and growth of isopods fed on three litter types ( Juncus roemerianus , Quercus virginiana and Pinus palustris ) and

M. Zimmer; S. C. Pennings; T. L. Buck; T. H. Carefoot

2002-01-01

343

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

Microsoft Academic Search

Salt marshes, most now embanked, together with genetically related wetlands and high intertidal flats, make a major environmental contribution to the lowland coasts of Northwest Europe. They occur in many different contexts, but chiefly on open and barrier coasts and in estuaries and embayments, and range greatly in scale, from a modest total that measure hundreds of square kilometres in

J. R. L. Allen

2000-01-01

344

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

345

Seasonal patterns in energy partitioning of two freshwater marsh ecosystems in the Florida Everglades  

NASA Astrophysics Data System (ADS)

analyzed energy partitioning in short- and long-hydroperiod freshwater marsh ecosystems in the Florida Everglades by examining energy balance components (eddy covariance derived latent energy (LE) and sensible heat (H) flux). The study period included several wet and dry seasons and variable water levels, allowing us to gain better mechanistic information about the control of and changes in marsh hydroperiods. The annual length of inundation is ~5 months at the short-hydroperiod site (25°26'16.5?N, 80°35'40.68?W), whereas the long-hydroperiod site (25°33'6.72?N, 80°46'57.36?W) is inundated for ~12 months annually due to differences in elevation and exposure to surface flow. In the Everglades, surface fluxes feed back to wet season precipitation and affect the magnitude of seasonal change in water levels through water loss as LE (evapotranspiration (ET)). At both sites, annual precipitation was higher than ET (1304 versus 1008 at the short-hydroperiod site and 1207 versus 1115 mm yr-1 at the long-hydroperiod site), though there were seasonal differences in the ratio of ET:precipitation. Results also show that energy balance closure was within the range found at other wetland sites (60 to 80%) and was lower when sites were inundated (60 to 70%). Patterns in energy partitioning covaried with hydroperiods and climate, suggesting that shifts in any of these components could disrupt current water and biogeochemical cycles throughout the Everglades region. These results suggest that the complex relationships between hydroperiods, energy exchange, and climate are important for creating conditions sufficient to maintain Everglades ecosystems.

Malone, Sparkle L.; Staudhammer, Christina L.; Loescher, Henry W.; Olivas, Paulo; Oberbauer, Steven F.; Ryan, Michael G.; Schedlbauer, Jessica; Starr, Gregory

2014-08-01

346

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

347

Pyriproxyfen for the control of Australian salt-marsh mosquito, Aedes vigilax.  

PubMed

The efficacy of pyriproxyfen against the Australian salt-marsh mosquito, Aedes vigilax, was examined in 2 laboratory and 1 semi-field study using both technical grade and formulated products. In a dose-response study, the median emergence inhibition (EI50) and EI95 values were determined to be 0.019 and 0.076 ppb, respectively, for pyriproxyfen technical grade, 0.021 and 0.092 ppb for a microencapsulated formulation (Sumilarv 90CS), and 0.054 and 0.236 ppb for the formulated s-methoprene product, Altosid Liquid Larvicide. A further laboratory comparison of the microencapsulated formulation of pyriproxyfen and Altosid, at the nominal field rate for Altosid, showed that both products provided 100% emergence inhibition and this was confirmed in a semi-field study, which also included a granular formulation of pyriproxyfen (Sumilarv 0.5G). PMID:22533086

Webb, Garry; Miller, Peter; Peters, Bryce

2012-03-01

348

Greenhouse Gas and Mercury Emissions from a Salt Marsh on the Bay of Fundy  

NASA Astrophysics Data System (ADS)

The Bay of Fundy, primarily situated between the provinces of New Brunswick and Nova Scotia in Canada is known have tides among the highest in the world, where tidal amplitudes have reached 17 m, and regularly exceed 12-13m. The reason for these extremely high tides has been attributed to basin morphology and tidal resonance. Along the margin of the Bay of Fundy, salt marshes are exposed to these high tidal ranges. These salt marshes have unknown greenhouse gas (CO2, CH4 specifically) and mercury trace gas budgets. Tides here exert significant pressure on salt marsh sediments, to the point where gases are visibly seen escaping around the waters edge. This pressure-driven gas transport phenomena is markedly different than most greenhouse gas releases from other sediments, which occurs primarily by diffusion. Our study site in Kingsport, NS, Canada also provides a unique opportunity to examine pressure-driven emissions using differential pressure measurements. This work is significant in determining the role of salt marshes in the carbon and mercury emission budgets in the maritime region, and their sensitivity to environmental forcings. For our study, mercury fluxes were measured using Teflon flux chamber technique with Tekran gaseous mercury analysis, while CO2 and CH4 fluxes were measured at 60 second intervals using a new technique called continuous timeseries-forced diffusion (CT-FD). A portable meteorological station was located on site, with soil temperature, solar radiation, soil O2, and soil-atmosphere differential pressure measurements logged continuously for 10 days and 19 tidal cycles. After the field deployment, the CO2 and CH4 instrumentation was moved to soil plots in mesocosm tidal-simulation benches to conduct experiments that would allow us to separate the difference between tidal forcings and thermally-driven microbial greenhouse gas production in sediments. In the field, differential pressure varied according to tidal cycles and was surprising in that rebound to atmospheric pressure rarely occurred. Instead, pressure gradients were sustained in the sediments during high (excess pressure) and low (pressure deficit) tides. While no compelling relationship appears evident between mercury, CO2, or CH4 flux and tidal height, ratios of flux to solar radiation suggest that tidal inundation and gas release does at least facilitate mercury release from sediments during peak flux times. Low gas diffusivity sediments (very fine, impermeable, compact) are potentially very important at these sites, potentially damping transport rates across the soil surface. Gas bubbles, which can be observed at the incoming waterline, may be preferentially emitted through more permeable sediment layers and subsurface sand channels rather than the surface. The Bay of Fundy setting provides a rather unique and challenging opportunity to study extreme examples of trace gas flux and gas transport dynamics.

O'Driscoll, N.; McArthur, G. S.; Risk, D. A.; Dalziel, J.; Beltrami, H.

2009-12-01

349

Prescribed fire and cutting as tools for reducing woody plant succession in a created salt marsh  

USGS Publications Warehouse

This paper reports on efforts to reduce woody successional growth by the native shrub Iva frutescens L. in a created salt marsh by using prescribed fire and cutting. Experimental treatments included a winter burn, cutting plants at ground level, and a combination burn-and-cut treatment, with replicate plots of each. Iva frutescens proved to be extremely hardy, with zero mortality following the cutting, burning, or combination treatment; similar levels of regrowth were observed for all treatments. Individual shrub response, however, was found to be related to initial plant size, ground water level and salinity, and two fire characteristics (total heating >60??C and total heat index >60??C). Fire severity, sediment nutrient concentrations, and other abiotic factors had no observable effects. ?? 2007 Springer Science+Business Media B.V.

Owens, A.B.; Proffitt, C.E.; Grace, J.B.

2007-01-01

350

Salt marsh plants as key mediators on the level of cadmium impact on microbial denitrification.  

PubMed

The fate of excess nitrogen in estuaries is determined by the microbial-driven nitrogen cycle, being denitrification a key process since it definitely removes fixed nitrogen as N2. However, estuaries receive and retain metals, which may negatively affect this process efficiency. In this study, we evaluated the role of salt marsh plants in mediating cadmium (Cd) impact on microbial denitrification process. Juncus maritimus and Phragmites australis from an estuary were collected together with the sediment involving their roots, each placed in vessels and maintained in a greenhouse, exposed to natural light, with tides simulation. Similar non-vegetated sediment vessels were prepared. After 3 weeks of accommodation, nine vessels (three per plant species plus three non-vegetated) were doped with 20 mg/L Cd(2+) saline solution, nine vessels were doped with 2 mg/L Cd(2+) saline solution and nine vessels were left undoped. After 10 weeks, vessels were dissembled and denitrification potential was measured in sediment slurries. Results revealed that the addition of Cd did not cause an effect on the denitrification process in non-vegetated sediment but had a clear stimulation in colonized ones (39 % for P. australis and 36 % for J. maritimus). In addition, this increase on denitrification rates was followed by a decrease on N2O emissions and on N2O/N2 ratios in both J. maritimus and P. australis sediments, increasing the efficiency of the N2O step of denitrification pathway. Therefore, our results suggested that the presence of salt marsh plants functioned as key mediators on the degree of Cd impact on microbial denitrification. PMID:24792983

Almeida, C Marisa R; Mucha, Ana P; da Silva, Marta Nunes; Monteiro, Maria; Salgado, Paula; Necrasov, Tatiana; Magalhães, Catarina

2014-09-01

351

Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities  

NASA Astrophysics Data System (ADS)

This paper reports changes in vegetation distribution and species cover in relation to soil factors and hydrology in a semiarid Mediterranean salt marsh adjacent to the Mar Menor saline lagoon. Species cover, soil salinity, and the groundwater level were monitored between 1991 and 1993 and between 2002 and 2004, and total organic carbon, total nitrogen, total phosphorus, nitrates, ammonium and exchangeable phosphorus were measured in the soils in both study periods. In addition, three soil profiles were described in August 1992 and August 2004. The results indicate an elevation of the water table throughout the 13-year period, which was attributable to water flowing from areas with intensive agriculture. Flooding increased and soil salinity dropped in the most saline sites and increased in the least saline ones. The morphology of the soil profiles reflected the increase in flooding periods, due to the appearance of a greyer matrix in the deeper horizons and a more diffuse pattern of Fe mottles. Following these environmental changes, Sarcocornia fruticosa, Phragmites australis and Juncus maritimus strongly expanded at the wettest sites, which led to the disappearance of the original zonation pattern. The cover of Limonium delicatulum, in turn, decreased with the increase in moisture but increased following the increase in salinity. Changes in soil nutrients were only very evident in the sandy soils of the beach, probably due to the influence of organic debris deposited on the shoreline by the storms and due to the strong increase in the colonisation of this habitat by perennial species. According to the results obtained, control measures are needed in order to preserve habitat diversity in this and other salt marshes of this area. Monitoring of the vegetation distribution could be a useful tool to identify environmental impacts, in order to implement remedial actions.

Álvarez-Rogel, J.; Jiménez-Cárceles, F. J.; Roca, M. J.; Ortiz, R.

2007-07-01

352

A regional assessment of salt marsh restoration and monitoring in the Gulf of Maine  

USGS Publications Warehouse

We compiled salt marsh monitoring datasets from 36 complete or imminent restoration projects in the Gulf of Maine to assess regional monitoring and restoration practices. Data were organized by functional indicators and restoration project types (culvert replacement, excavation works, or ditch plugging) then pooled to generate mean values for indicators before restoration, after restoration, and at reference sites. Monitoring data were checked against the regional standards of a voluntary protocol for the Gulf of Maine. Data inventories showed that vegetation and salinity indicators were most frequently collected (89 and 78% of sites, respectively), whereas nekton, bird, and hydrologic measures were collected at only about half of the sites. Reference conditions were monitored at 72% of sites. Indicators were analyzed to see if project sites were degraded relative to reference areas and to detect ecological responses to restoration activities. Results showed that compared to reference areas, prerestoration sites had smaller tidal ranges, reduced salinity levels, greater cover of brackish plants species, and lower cover of halophyte plants. Following restoration, physical factors rebounded rapidly with increased flood and salinity levels after about one year, especially for culvert projects. Biological responses were less definitive and occurred over longer time frames. Plant communities trended toward recovered halophytes and reduced brackish species at 3+ years following restoration. Nekton and avian indicators were indistinguishable among reference, impacted, and restored areas. The protocol was successful in demonstrating restoration response for the region, but results were limited by regional inconsistencies in field practices and relatively few multiyear datasets. To improve future assessment capabilities, we encourage greater adherence to the standard protocol throughout the Gulf of Maine salt marsh restoration community.

Konisky, R.A.; Burdick, D.M.; Dionne, M.; Neckles, H.A.

2006-01-01

353

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. PMID:17567893

Taillefert, Martial; Neuhuber, Stephanie; Bristow, Gwendolyn

2007-01-01

354

Mercury uptake and allocation in Juncus maritimus: implications for phytoremediation and restoration of a mercury contaminated salt marsh.  

PubMed

Juncus maritimus is the most abundant macrophyte in Laranjo bay, a Portuguese salt marsh heavily polluted by mercury (Hg). With the aim to elucidate the role of this species in the salt marsh Hg cycling and restoration, plants were harvested between March 2006 and January 2008 from four locations differing in Hg contamination. Metal uptake and distribution between plant organs were evaluated, biomass and Hg pools were also determined. Results showed that J. maritimus may influence the sediment pH and Eh, thus increasing the Hg available for uptake. Most (95-98%) of the absorbed Hg was retained belowground, phytostabilizing the metal and reducing the amount of Hg in the sediments. These results suggest that in salt marshes dominated by J. maritimus the approach could be phytostabilization, where these plants can be used to immobilize metals and store them belowground, reducing the pool of bioavailable Hg within contaminated marshes and acting as a sink rather than a source of contamination to the surrounding areas. PMID:22739436

Figueira, Etelvina; Freitas, Rosa; Pereira, Eduarda; Duarte, Armando

2012-08-01

355

Assessment of phosphogypsum impact on the salt-marshes of the Tinto river (SW Spain): role of natural attenuation processes.  

PubMed

About 120 Mton of phosphogypsum from the fertiliser industry were stack-piled on the salt-marshes of the Tinto river (Spain). This paper investigates the capacity of salt-marshes to attenuate contamination due to downward leaching from phosphogypsum. Solids and pore-waters were characterized at different depths of the pile to reach the marsh-ground. In superficial zones, metals were highly mobile, and no reduced sulphur was found. However, pollutant concentration decreased in the pore-water in deeper oxygen-restricted zones. Metal removal occurred by precipitation of newly formed sulphides, being this process main responsible for the contamination attenuation. Pyrite-S was the main sulphide component (up to 2528 mg/kg) and occurred as framboids, leading to high degrees of pyritization (up to 97%). The sulphidization reaction is Fe-limited; however, excess of acid-volatile sulphide over other metals cause precipitation of other sulphides, mainly of Cu and As. This decrease in metal mobility significantly minimises the impact of phosphogypsums on the salt-marshes. PMID:21992931

Pérez-López, Rafael; Castillo, Julio; Sarmiento, Aguasanta M; Nieto, José M

2011-12-01

356

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. PMID:24348464

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

2013-01-01

357

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

358

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

359

Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated  

E-print Network

, whereas a mosaic of marsh hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus, whereas a mosaic of marsh hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus

Bertness, Mark D.

360

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...

361

Salt Marsh development studies at Waquoit Bay, Massachusetts: Influence of geomorphology on long-term plant community structure  

NASA Astrophysics Data System (ADS)

Stochastic events relating to beach formation and inlet dynamics have been the major factors influencing the development of the Waquoit Bay tidal marshes. This results from the physical structure of the Waquoit Bay system where tidal exchange is limited to one or two small inlets and is in contrast to marsh development in nearby Barnstable Marsh where direct unrestricted exchange with Cape Cod Bay has smoothed the effects of stochastic events on vegetation development. We contend that vegetation development in salt marshes where connections to adjacent waters are restricted will be dominated by abiotic factors (e.g. storms, sedimentation rates, etc.) while those marshes directly linked to open bodies of water and where alterations to hydrodynamic factors are gradual, autecological processes (e.g. interspecific competition) will dominate long-term plant community development. The results from the five marsh systems within the Waquoit Bay complex suggest that once a vegetation change occurs the new community tended to persist for long periods of time (100's-1000's years). Stability of the 'new' community appeared to depend upon the stability of the physical structure of the system and/or time between perturbations necessary to allow the slower autecological processes to have a discernable effect. In order for the plant community to persist as long as observed, the vegetation must also be exerting an influence on the processes of development. Increased production of roots and rhizomes and growth characteristics (density of culms) are some of the factors which help to maintain long-term species dominance. It is clear from this investigation that the structure of the plant community at any one point in time is dependent upon numerous factors including historical developmental influences. To properly assess changes to the present plant community or determine recent rates of accretion, historic developmental trends must be considered. The factors that have influenced the development of marsh in the past will be important in understanding and formulating predictive models in the future.

Orson, Richard A.; Howes, Brian L.

1992-11-01

362

Importance of Vascular Plant and Algal Production to Macro-invertebrate Consumers in a Southern California Salt Marsh  

NASA Astrophysics Data System (ADS)

The dietary importance of marsh vascular plants (primarily Salicornia virginica), algae and upland particulate inputs to macro-invertebrate consumers was studied in Carpinteria Salt Marsh, southern California, using stable carbon and nitrogen isotope ratios. This marsh is predominantly a marine or hypersaline system and succulents are the most common vascular plant species. Of invertebrates collected from the vegetated marsh, tidal flats and channels, only detritivores from the vegetated marsh ( Traskorchestia traskiana, Melampus olivaceus) had isotope values (? 13C=-20‰) that suggested some use of Salicornia-derived carbon. T. traskianacultured in the laboratory on decomposing S. virginicaor blue-green micro-algal mat had distinctive isotopic signatures, reflecting the capability of this consumer to assimilate carbon and nitrogen derived from these sources. The ? 13C values (generally -16‰ to -15‰) of species from tidal flats and channels (e.g. Cerithidea californica, Protothaca staminea, Mytilus galloprovincialis, Neotrypaea californiensis) were most similar to values for benthic algae and phytoplankton. Specimens of M. galloprovincialisalong a gradient of presumed increase in marine influence had similar isotope values, suggesting little contribution to diet from upland runoff. The present results differ most noticeably from published values in the 13C enrichment of suspension-feeders, suggesting the use of resuspended 13C-enriched benthic microalgae in tidal channels by these consumers, and in the 13C depletion and 15N enrichment of plants and consumers along a portion of the marsh boundary receiving inputs of nutrient-enriched perched groundwater. In general, the isotopic composition of macro-invertebrates indicated the incorporation of algal production rather than of S. virginicaor upland sources into the marsh food web.

Page, H. M.

1997-12-01

363

Marine Ecosystems  

NSDL National Science Digital Library

Marine ecosystem introduction to shorelines, temperate oceans, and tropical oceans. Shoreline topics cover sandy and rocky shores, barrier islands, tide pools, estuaries, salt marshes, mud flats, mangrove forests, tides, waves, currents, and shoreline animals. Students can learn about temperate ocean zonation, light, forests, patterns, and animals. The tropical oceans chapter features coral reefs and tropical ocean animals. This site would provide a comprehensive introduction for a marine ecosystems or an ocean science unit.

364

The greenhouse gas flux and potential global warming feedbacks of a northern macrotidal and microtidal salt marsh  

USGS Publications Warehouse

Conversion of wetlands by drainage for agriculture or other anthropogenic activities could have a negative or positive feedback to global warming (GWF). We suggest that a major predictor of the GWF is salinity of the wetland soil (a proxy for available sulfate), a factor often ignored in other studies. We assess the radiative balance of two northern salt marshes with average soil salinities > 20 ppt, but with high (macro-) and low (micro-) tidal amplitudes. The flux of greenhouse gases from soils at the end of the growing season averaged 485 ± 253 mg m-2 h-1, 13 ± 30 ?g m-2 h-1, and 19 ± 58 ?g m-2 h-1 in the microtidal marsh and 398 ± 201 mg m-2 h-1, 2 ± 26 ?g m-2 h-1, and 35 ± 77 ?g m-2 h-1 in the macrotidal marsh for CO2, N2O, and CH4, respectively. High rates of C sequestration mean that loss of these marshes would have a radiative balance of - 981 CO2_eq. m-2 yr-1 in the microtidal and - 567 CO2_eq. m-2 yr-1 in the macrotidal marsh.

Chmura, Gail L.; Kellman, Lisa; Guntenspergen, Glenn R.

2011-01-01

365

The greenhouse gas flux and potential global warming feedbacks of a northern macrotidal and microtidal salt marsh  

NASA Astrophysics Data System (ADS)

Conversion of wetlands by drainage for agriculture or other anthropogenic activities could have a negative or positive feedback to global warming (GWF). We suggest that a major predictor of the GWF is salinity of the wetland soil (a proxy for available sulfate), a factor often ignored in other studies. We assess the radiative balance of two northern salt marshes with average soil salinities > 20 ppt, but with high (macro-) and low (micro-) tidal amplitudes. The flux of greenhouse gases from soils at the end of the growing season averaged 485 ± 253 mg m - 2 h - 1, 13 ± 30 µg m - 2 h - 1, and 19 ± 58 µg m - 2 h - 1 in the microtidal marsh and 398 ± 201 mg m - 2 h - 1, 2 ± 26 µg m - 2 h - 1, and 35 ± 77 µg m - 2 h - 1 in the macrotidal marsh for CO2, N2O, and CH4, respectively. High rates of C sequestration mean that loss of these marshes would have a radiative balance of - 981 CO2_eq. m - 2 yr - 1 in the microtidal and - 567 CO2_eq. m - 2 yr - 1 in the macrotidal marsh.

Chmura, Gail L.; Kellman, Lisa; Guntenspergen, Glenn R.

2011-10-01

366

Marshes at Chincoteague Channel  

USGS Multimedia Gallery

Seagrass marshes in Chincoteague Channel. Saltwater and barrier marshes are important ecosystems that protect inland habitat and communities from ocean storms. They also provide important habitat for migrating water fowl. A duck hunting blind can be seen in the right....

367

Modeling the influence of changing storm patterns on the ability of a salt marsh to keep pace with sea level rise  

NASA Astrophysics Data System (ADS)

Previous predictions on the ability of coastal salt marshes to adapt to future sea level rise (SLR) neglect the influence of changing storm activity that is expected in many regions of the world due to climate change. We present a new modeling approach to quantify this influence on the ability of salt marshes to survive projected SLR, namely, we investigate the separate influence of storm frequency and storm intensity. The model is applied to a salt marsh on the German island of Sylt and is run for a simulation period from 2010 to 2100 for a total of 13 storm scenarios and 48 SLR scenarios. The critical SLR rate for marsh survival, being the maximum rate at which the salt marsh survives until 2100, lies between 19 and 22 mm yr-1. Model results indicate that an increase in storminess can increase the ability of the salt marsh to accrete with sea level rise by up to 3 mm yr-1, if the increase in storminess is triggered by an increase in the number of storm events (storm frequency). Meanwhile, increasing storminess, triggered by an increase in the mean storm strength (storm intensity), is shown to increase the critical SLR rate for which the marsh survives until 2100 by up to 1 mm yr-1 only. On the basis of our results, we suggest that the relative importance of storm intensity and storm frequency for marsh survival strongly depends on the availability of erodible fine-grained material in the tidal area adjacent to the salt marsh.

Schuerch, M.; Vafeidis, A.; Slawig, T.; Temmerman, S.

2013-03-01

368

Low persistence of Bacillus thuringiensis serovar israelensis spores in four mosquito biotopes of a salt marsh in southern France.  

PubMed

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). 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 Juncus maritimus) and the physical and chemical characteristics of the soil. We sampled water, soil, and plants at various times before and after the applications (from spring to autumn, 2001) and quantified the spores of B. thuringiensis (Bt) and Bacillus species. The B. cereus group accounted for between 0% and 20% of all Bacillus spp. before application depending on the larval biotope. No Bti were found before application. The variation in the quantity of bacilli during the mosquito breeding season depended more on the larval biotope than on the season or the larvicidal application. More bacilli were found in soil (10(4)-10(6) spores/g) than on plant samples (10(2)-10(4) spores/g). The abundance in water (10(5) to 10(7) spores/L) appeared to be correlated to the water level of the breeding site. The number of Bti spores increased just after application, after declining; no spores were detected in soil or water 3 months after application. However, low numbers of Bti spores were present on foliage from three of the four studied plant strata. In conclusion, the larvicidal application has very little impact on Bacillus spp. flora after one breeding season (two applications). PMID:16328650

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

2005-11-01

369

Organochlorine pesticide and polychlorinated biphenyl residues in selected fauna from a New Jersey salt marsh--1967 vs. 1973  

USGS Publications Warehouse

More than a half million pounds of DDT were applied to control mosquitoes in salt marsh estuaries of Cape May County, New Jersey, from 1946 to 1966. The use of DDT was discontinued in the County after 1966. In 1967, mean concentrations of DDT and metabolites ranged from 0.63 to 9.05 ppm in aquatic fauna, but by 1973 mean residue levels had decreased 84 to 99 percent among nine species. DDE was still present at reduced levels in nearly all samples in 1973, but other DDT isomers had mostly disappeared. Dieldrin was detected only in clapper rails, and residue levels decreased during the period. Mean concentrations of PCB's increased in the clapper rail, remained the same in the fiddler crab and mud snail, and decreased in the sheepshead minnow, mummichog, striped killifish, and salt marsh snail. Small amounts of mirex, toxaphene, cis-chlordane (and/or trans-nonachlor), oxychlordane, and HCB were detected in a few specimens.

Klaas, E.E.; Belisle, A.A.

1977-01-01

370

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

371

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

372

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

373

Where temperate meets tropical: Multi-factorial effects of elevated CO2, nitrogen enrichment, and competition on a mangrove-salt marsh community  

USGS Publications Warehouse

Our understanding of how elevated CO2 and interactions with other factors will affect coastal plant communities is limited. Such information is particularly needed for transitional communities where major vegetation types converge. Tropical mangroves (Avicennia germinans) intergrade with temperate salt marshes (Spartina alterniflora) in the northern Gulf of Mexico, and this transitional community represents an important experimental system to test hypotheses about global change impacts on critical ecosystems. We examined the responses of A. germinans (C3) and S. alterniflora (C4), grown in monoculture and mixture in mesocosms for 18 months, to interactive effects of atmospheric CO2 and pore water nitrogen (N) concentrations typical of these marshes. A. germinans, grown without competition from S. alterniflora, increased final biomass (35%) under elevated CO2 treatment and higher N availability. Growth of A. germinans was severely curtailed, however, when grown in mixture with S. alterniflora, and enrichment with CO2 and N could not reverse this growth suppression. A field experiment using mangrove seedlings produced by CO2- and N-enriched trees confirmed that competition from S. alterniflora suppressed growth under natural conditions and further showed that herbivory greatly reduced survival of all seedlings. Thus, mangroves will not supplant marsh vegetation due to elevated CO2 alone, but instead will require changes in climate, environmental stress, or disturbance to alter the competitive balance between these species. However, where competition and herbivory are low, elevated CO2 may accelerate mangrove transition from the seedling to sapling stage and also increase above- and belowground production of existing mangrove stands, particularly in combination with higher soil N. ?? 2008 The Authors Journal compilation ?? 2008 Blackwell Publishing Ltd.

McKee, K.L.; Rooth, J.E.

2008-01-01

374

Tidal salt marsh sediment in California, USA: part 3. Current and historic toxicity potential of contaminants and their bioaccumulation.  

PubMed

To assess potential health risks to benthic organisms from exposure to toxic contaminants, sediment chemistry data from five salt marshes along the coast of California were compared with threshold effects levels (TELs) and probable effects levels (PELs). As an integrated estimate of toxicity potential of multiple contaminants, mean PEL quotients (mPELQs) were used to categorize sampling stations into three groups: high (>0.5), medium (0.1-0.5) and low (<0.1). In all sediments from Stege Marsh located in San Francisco Bay, at least one contaminant exceeded PELs by up to 18-fold and mPELQs were higher than 0.7. Mean PELQs in two core sediments from eastern Stege Marsh ranged from 0.7 to 2.1, indicating that benthic organisms in Stege Marsh may have been adversely affected for several decades. To investigate bioavailability and bioaccumulation of contaminants in sediments, longjaw mudsuckers (Gillichthys mirabilis) were transplanted to six Stege Marsh stations for 60 days. Body burdens of organic contaminants clearly showed that they were readily available for benthic organisms. Measured concentrations of organic contaminants in mudsuckers were similar to estimated levels computed using a theoretical bioaccumulation potential model. Levels of PCBs and arsenic in mudsuckers were higher than screening values set as guidelines for the protection of humans and levels of PCBs and DDTs were higher than criteria for wildlife. The results of this study indicate that the levels of contaminants in Stege Marsh sediments may not fully support the well-being of benthic organisms and also may provoke adverse effects on fish-eating animals and humans through trophic transfer. PMID:18316112

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

2008-05-01

375

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

376

The effect of multiple stressors on salt marsh end-of-season biomass  

USGS Publications Warehouse

It is becoming more apparent that commonly used statistical methods (e.g., analysis of variance and regression) are not the best methods for estimating limiting relationships or stressor effects. A major challenge of estimating the effects associated with a measured subset of limiting factors is to account for the effects of unmeasured factors in an ecologically realistic matter. We used quantile regression to elucidate multiple stressor effects on end-of-season biomass data from two salt marsh sites in coastal Louisiana collected for 18 yr. Stressor effects evaluated based on available data were flooding, salinity, air temperature, cloud cover, precipitation deficit, grazing by muskrat, and surface water nitrogen and phosphorus. Precipitation deficit combined with surface water nitrogen provided the best two-parameter model to explain variation in the peak biomass with different slopes and intercepts for the two study sites. Precipitation deficit, cloud cover, and temperature were significantly correlated with each other. Surface water nitrogen was significantly correlated with surface water phosphorus and muskrat density. The site with the larger duration of flooding showed reduced peak biomass, when cloud cover and surface water nitrogen were optimal. Variation in the relatively low salinity occurring in our study area did not explain any of the variation in Spartina alterniflora biomass. ?? 2006 Estuarine Research Federation.

Visser, J.M.; Sasser, C.E.; Cade, B.S.

2006-01-01

377

Influence of different salt marsh plants on hydrocarbon degrading microorganisms abundance throughout a phenological cycle.  

PubMed

The influence of Juncus maritimus, Phragmites australis, and Triglochin striata on hydrocarbon degrading microorganisms (HD) in Lima River estuary (NW Portugal) was investigated through a year-long plant life cycle. Sediments un-colonized and colonized (rhizosediments) by those salt marsh plants were sampled for HD, total cell counts (TCC), and total petroleum hydrocarbons (TPHs) assessment. Generally, TCC seemed to be markedly thriving by the presence of roots, but without significant (p > 0.05) differences among rhizosediments. Nevertheless, plants seemed to have a distinct influence on HD abundance, particularly during the flowering season, with higher HD abundance in the rhizosediments of the fibrous roots plants (J. maritimus < P. australis < T. striata). Our data suggest that different plants have distinct influence on the dynamics of HD populations within its own rhizosphere, particularly during the flowering season, suggesting a period of higher rhizoremediation activity. Additionally, during the vegetative period, plants with fibrous and dense root system tend to retain hydrocarbons around their belowground tissues more efficiently than plants with adventitious root system. Overall results indicate that fibrous root plants have a higher potential to promote hydrocarbons degradation, and that seasonality should be taken into account when designing long-term rhizoremediation strategies in estuarine areas. PMID:23819270

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

2013-01-01

378

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

PubMed

The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three salt-marsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management. PMID:21646131

Espinar, José L; García, Luis V; Clemente, Luis

2005-07-01

379

Can salt marsh plants influence levels and distribution of DDTs in estuarine areas?  

NASA Astrophysics Data System (ADS)

Sediments are depositories of toxic substances such as organochlorine pesticides and there is a global need for their removal in contaminated environments. Studies that combine contaminated sediments and phytoremediation are relatively recent and their number has been increasing. This work aimed to investigate whether salt marsh plants (sea club-rush Scirpus maritimus, sea rush Juncus maritimus and sea purslane Halimione portulacoides) can favor DDT and metabolites remediation in estuarine environment. For this purpose the levels of DDT, DDE and DDD were compared in vegetated and non-vegetated sediments from an estuary in the North of Portugal ( in-situ study) and from another in the South of Portugal ( ex-situ study). Results obtained both in the in-situ study, involving S. maritimus and J. maritimus, and in the ex-situ study, involving H. portulacoides, indicated that these plants did not have a significant role in DDTs removal and/or degradation. Therefore, it seems that the tested plants cannot influence levels and distribution of DDTs in estuarine areas.

Carvalho, Pedro N.; Rodrigues, Pedro Nuno R.; Evangelista, Rafael; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

2011-07-01

380

Mercury in non-breeding sparrows of North Carolina salt marshes.  

PubMed

We captured Nelson's, Saltmarsh and Seaside Sparrows (Ammodramus nelsoni, A. caudacutus and A. maritimus) at three salt marsh sites near Wrightsville Beach, North Carolina during five non-breeding seasons (September through April, 2006-2011). We analyzed breast feather samples from all of these seasons and blood and first primary feather (P1) samples from three seasons (2008-2011) for mercury (Hg). Generalized linear models were used to test for the impact of species, season, site and month on blood Hg, species, season and site on P1 Hg and species and season on breast feather Hg. The best-fit model for blood indicated that Hg varied among species, seasons and months. Saltmarsh Sparrows maintain higher blood Hg than Nelson's and Seaside Sparrows during the non-breeding season while they are feeding in mixed flocks. In Nelson's and Seaside Sparrows, blood Hg decreased during mid-winter compared to early fall and late spring. Breast feather and P1 Hg varied among species with Saltmarsh Sparrows exhibiting higher concentrations than the other two species, while Nelson's Sparrows had lower concentrations than the other two species. Breast feather Hg was higher in the final three seasons than in the first two. Our results indicate that Hg exposure on breeding sites may be increasing and that high levels of Hg exposure during the breeding season may affect blood Hg concentrations year-round in Saltmarsh Sparrows. Our data thus provide a baseline for future Hg assessments in these species in NC. PMID:21947667

Winder, Virginia L; Emslie, Steven D

2012-03-01

381

Microscale sulfur cycling in the phototrophic pink berry consortia of the Sippewissett Salt Marsh  

PubMed Central

Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the ‘pink berry’ consortia of the Sippewissett Salt Marsh through an integrative study at the microbial scale. The pink berries are macroscopic, photosynthetic microbial aggregates composed primarily of two closely associated species: sulfide-oxidizing purple sulfur bacteria (PB-PSB1) and sulfate-reducing bacteria (PB-SRB1). Using metagenomic sequencing and 34S-enriched sulfate stable isotope probing coupled with nanoSIMS, we demonstrate interspecies transfer of reduced sulfur metabolites from PB-SRB1 to PB-PSB1. The pink berries catalyse net sulfide oxidation and maintain internal sulfide concentrations of 0–500??m. Sulfide within the berries, captured on silver wires and analysed using secondary ion mass spectrometer, increased in abundance towards the berry interior, while ?34S-sulfide decreased from 6‰ to ?31‰ from the exterior to interior of the berry. These values correspond to sulfate–sulfide isotopic fractionations (15–53‰) consistent with either sulfate reduction or a mixture of reductive and oxidative metabolisms. Together this combined metagenomic and high-resolution isotopic analysis demonstrates active sulfur cycling at the microscale within well-structured macroscopic consortia consisting of sulfide-oxidizing anoxygenic phototrophs and sulfate-reducing bacteria. PMID:24428801

Wilbanks, Elizabeth G; Jaekel, Ulrike; Salman, Verena; Humphrey, Parris T; Eisen, Jonathan A; Facciotti, Marc T; Buckley, Daniel H; Zinder, Stephen H; Druschel, Gregory K; Fike, David A; Orphan, Victoria J

2014-01-01

382

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

383

Long-term impacts of disturbance on nitrogen-cycling bacteria in a New England salt marsh  

PubMed Central

Recent studies on the impacts of disturbance on microbial communities indicate communities show differential responses to disturbance, yet our understanding of how different microbial communities may respond to and recover from disturbance is still rudimentary. We investigated impacts of tidal restriction followed by tidal restoration on abundance and diversity of denitrifying bacteria, ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA) in New England salt marshes by analyzing nirS and bacterial and archaeal amoA genes, respectively. TRFLP analysis of nirS and betaproteobacterial amoA genes revealed significant differences between restored and undisturbed marshes, with the greatest differences detected in deeper sediments. Additionally, community patterns indicated a potential recovery trajectory for denitrifiers. Analysis of archaeal amoA genes, however, revealed no differences in community composition between restored and undisturbed marshes, but we detected significantly higher gene abundance in deeper sediment at restored sites. Abundances of nirS and betaproteobacterial amoA genes were also significantly greater in deeper sediments at restored sites. Porewater ammonium was significantly higher at depth in restored sediments compared to undisturbed sediments, suggesting a possible mechanism driving some of the community differences. Our results suggest that impacts of disturbance on denitrifying and ammonia-oxidizing communities remain nearly 30 years after restoration, potentially impacting nitrogen-cycling processes in the marsh. We also present data suggesting that sampling deeper in sediments may be critical for detecting disturbance effects in coastal sediments.

Bernhard, Anne E.; Dwyer, Courtney; Idrizi, Adrian; Bender, Geoffrey; Zwick, Rachel

2015-01-01

384

Primary productivity of angiosperm and macroalgae dominated habitats in a New England salt marsh: a comparative analysis  

USGS Publications Warehouse

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 ? 106 kg y-1 of biomass (1?2 ? 106 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

385

DETRITUS PROCESSING AND MINERAL CYCLING IN SEAGRASS 'ZOSTERA' LITTER IN AN OREGON SALT MARSH  

EPA Science Inventory

In estuaries where seagrass beds adjoin marshes, the import and decomposition of seagrass litter in the marsh provide a mechanism for retaining nutrients within the wetlands and preventing loss to adjacent oceanic waters. Several aspects of the influence of seagrass litter on an ...

386

Influence of soil properties on trace element availability and plant accumulation in a Mediterranean salt marsh polluted by mining wastes: Implications for phytomanagement  

Microsoft Academic Search

The aims of this study were to determine the factors which control metal and As phytoavailability in the different microenvironments (Sand Dunes, Salt Flat, Dry River and Shrubs) present at a Mediterranean salt marsh polluted by mining wastes. We performed a field study following a plot sampling survey. The analyses of soil parameters (pH, electrical conductivity (EC), organic carbon contents,

H. M. Conesa; A. María-Cervantes; J. Álvarez-Rogel; M. N. González-Alcaraz

2011-01-01

387

Comparison of Nitrogen Fixation Activity in Tall and Short Spartina alterniflora Salt Marsh Soils 1  

PubMed Central

A comparison of the N2 fixers in the tall Spartina alterniflora and short S. alterniflora marsh soils was investigated. Zero-order kinetics and first-order kinetics of acetylene reduction were used to describe the activity of the N2 fixers in marsh soil slurries. It was found that the Vmax values were approximately 10 times greater for the N2 fixers in the tall Spartina than in the short Spartina marsh when raffinose was used as the energy source. In addition, the (Ks + Sn) values were approximately 4 to 15 times lower for the N2 fixers in the tall Spartina than in short Spartina marsh. First-order kinetics of nitrogen fixation for several substrates indicate that the N2 fixers in the tall Spartina marsh were two to seven times more active than those in the short Spartina marsh. Ammonium chloride (25 ?g/ml) did not inhibit nitrogen fixation in the tall Spartina marsh, but there was a 50% inhibition in nitrogen fixation in the short Spartina marsh. On the other hand, sodium nitrate inhibited nitrogen fixation almost 100% at 25 ?g/ml in both soil environments. Amino nitrogen (25 to 100 ?g/ml) had little or no effect on nitrogen fixation. The results indicate that the N2 fixers in the tall Spartina marsh were physiologically more responsive to nutrient addition than those in the short Spartina marsh. This difference in the two populations may be related to the difference in daily tidal influence in the respective areas and thus provide another explanation for the enhanced S. alterniflora production in the creek bank soil system. PMID:16345213

Hanson, Roger B.

1977-01-01

388

Influence of diesel contamination on the benthic microbial/meiofaunal food web of a Louisiana salt marsh  

SciTech Connect

The authors studied the influence of diesel-contaminated sediments on the benthic microbial/meiofaunal food web from a Louisiana salt marsh. Diesel-contaminated sediment was added to microcosms (intact cores of marsh mud) in a range of doses, and a suite of microbial and meiofaunal responses were measured over a 28-day period. The authors measured bacterial and microalgal (Chl a) abundance, bacterial and microalgal activity using radiotracers ({sup 14}C-acetate and {sup 14}CO{sub 2}, respectively), meiofaunal grazing on microalgae, meiofaunal community structure, and meiofaunal physiological condition. Preliminary results indicate that diesel-contaminated sediments influence microalgal biomass and activity, as well as the life histories of benthic copepod species.

Carman, K.R.; Fleeger, J.W.; Pomarico, S. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Zoology

1994-12-31

389

Stratification and loading of fecal indicator bacteria (FIB) in a tidally muted urban salt marsh.  

PubMed

Stratification and loading of fecal indicator bacteria (FIB) were assessed in the main tidal channel of the Ballona Wetlands, an urban salt marsh receiving muted tidal flows, to (1) determine FIB concentration versus loading within the water column at differing tidal flows, (2) identify associations of FIB with other water quality parameters, and (3) compare wetland FIB concentrations to the adjacent estuary. Sampling was conducted four times during spring-tide events; samples were analyzed for FIB and turbidity (NTU) four times over a tidal cycle at pre-allocated depths, depending on the water level. Additional water quality parameters measured included temperature, salinity, oxygen, and pH. Loadings were calculated by integrating the stratified FIB concentrations with water column cross-sectional volumes corresponding to each depth. Enterococci and Escherichia coli were stratified both by concentration and loading, although these variables portrayed different patterns over a tidal cycle. Greatest concentrations occurred in surface to mid-strata levels, during flood tides when contaminated water flowed in from the estuary, and during ebb flows when sediments were suspended. Loading was greatest during flood flows and diminished during low tide periods. FIB concentrations within the estuary often were significantly greater than those within the wetland tide channel, supporting previous studies that the wetlands act as a sink for FIB. For public health water quality monitoring, these results indicate that more accurate estimates of FIB concentrations would be obtained by sampling a number of points within a water column rather than relying only on single surface samples. PMID:25647802

Johnston, Karina K; Dorsey, John H; Saez, Jose A

2015-03-01

390

Sulfate reduction and other sedimentary biogeochemistry in a northern New England salt marsh  

NASA Technical Reports Server (NTRS)

Sulfate reduction rates, dissolved iron and sulfide concentrations, and titration alkalinity were measured in salt marsh soils along a transect that included areas inhabited by both the tall and short forms of Spartina alterniflora and by Spartina patens. Pore waters were collected with in situ 'sippers' to acquire temporal data from the same location without disturbing plant roots. During 1984, data collected at weekly intervals showed rapid temporal changes in belowground biogeochemical processes that coincided with changes in S. alterniflora physiology. Rates of SO4(-2) reduction increased fivefold (to greater than 2.5 micromol ml(sup -1)d(sup -1)) when plants began elongating aboveground yet decreased fourfold upon plant flowering. This rapid increase in rates of SO4(-2) reduction must have been fueled by dissolved organic matter released from roots only during active growth. Once plants flowered, the supply of oxidants to the soil decreased and sulfide and alkalinity concentrations increased despite decreases in SO4(-2) reduction and increases in SO4(-2):Cl(-) ratios. Sulfide concentrations were highest in soils inhabited by tallest plants. During 1985, S. alterniflora became infested with fly larvae (Chaetopsis apicalis John) and aboveground growth ceased in late June. This cessation was accompanied by decreased rates of SO4(-2) reduction similar to those noted during the previous year when flowering occurred. After the fly infestation, the pore-water chemical profiles of these soils resembled profiles of soils inhabited by the short form of S. alterniflora. The SO4(-2) reduction rates in S. patens soils are the first reported. Rates were similar to those in S. alterniflora except that they did not increase greatly when S. patens was elongating. Tidal and rainfall events produced desiccation-saturation cycles that altered redox conditions in the S. patens soils, resulting in rapid changes in the dissolution and precipitation of iron and in the magnitude and spatial distribution of SO4(-2) reduction.

Hines, Mark E.; Knollmeyer, Stephen L.; Tugel, Joyce B.

1992-01-01

391

Utilization of a saltwater-marsh ecosystem for the management of seafood-processing wastewater  

SciTech Connect

The report presents the results of a cooperative study that examined the potential for using a saltwater wetland to manage seafood-processing wastewater. An irregularly flooded black needlerush (Juncus roemerianus) marsh located at Point aux Pins in coastal Alabama was selected for the study. The study determined that the application of seafood-processing wastewater to the marsh affected a number of the marsh's water-quality characteristics in direct relation to the wastewater loading rate. However, monitoring of the marsh flora and fauna showed virtually no impact at any of the experimental loading rates. As a result of the study a number of design and loading criteria are suggested for any future projects involving wastewater discharges to saltwater wetlands.

Not Available

1986-10-01

392

ECOSYSTEM ECOLOGY The effects of tree establishment on water and salt dynamics  

E-print Network

ECOSYSTEM ECOLOGY The effects of tree establishment on water and salt dynamics in naturally salt an imprint on salt accumulation and distribution patterns. We explored how the conversion of native grasslands to oak plantations affected the abundance and distribution of salts on soils and groundwater

Nacional de San Luis, Universidad

393

Mercury-resistant bacteria from salt marsh of Tagus Estuary: the influence of plants presence and mercury contamination levels.  

PubMed

Mercury (Hg) contamination of aquatic systems has been recognized as a global, serious problem affecting both wildlife and humans. High levels of Hg, in particular methylmercury (MeHg), were detected in surface sediments of Tagus Estuary. MeHg is neurotoxic and its concentration in aquatic systems is dependent upon the relative efficiency of reduction, methylation, and demethylation processes, which are mediated predominantly by the microbial community, in particular mercury-resistant (HgR) bacteria. Plants in contaminated ecosystems are known to take up Hg via plant roots. Therefore, the aims of this study were to (1) isolate and characterize HgR bacteria from a salt marsh of Tagus Estuary (Rosário) and (2) determine HgR bacteria levels in the rhizosphere and, consequently, their influence in metal cycling. To accomplish this objective, sediments samples were collected during the spring season in an area colonized by Sacocornia fruticosa and Spartina maritima and compared with sediments without plants. From these samples, 13 aerobic HgR bacteria were isolated and characterized morphologically, biochemically, and genetically, and susceptibility to Hg compounds, Hg(2+), and MeHg was assessed by determination of minimal inhibitory concentration (MIC). Genetically, the mer operon was searched by polymerase chain reaction (PCR) and 16S rRNA sequencing was used for bacterial identification. Results showed that the isolates were capable of growing in the presence of high Hg concentration with MIC values for HgCl2 and MeHgCl in the ranges of 1.7-4.2 ?g/ml and 0.1-0.9 ?g/ml, respectively. The isolates from sediments colonized with Sacocornia fruticosa displayed higher resistance levels compared to ones colonized with Spartina maritima. Bacteria isolates showed different capacity of Hg accumulation but all displayed Hg volatilization capabilities (20-50%). Mer operon was found in two isolates, which genetically confirmed their capability to convert Hg compounds by reducing them to Hg(0). Thus, these results are the first evidence of the relevance of interaction between bacteria and plants in Hg cycling in Tagus Estuary. PMID:25072727

Figueiredo, Neusa L L; Areias, Andreia; Mendes, Ricardo; Canário, João; Duarte, Aida; Carvalho, Cristina

2014-01-01

394

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

395

The effects of cattle grazing on Texas coastal salt marsh plants and birds.  

E-print Network

??Cattle grazing effects on plants and birds were examined in Spartina alterniflora-dominated marsh and adjacent Sporobolus virginicus-dominated hummocks within high tidal flats on Galveston Island,… (more)

Yeargan, Catherine A

2012-01-01

396

Management Questions Tidal Marsh Restoration  

E-print Network

Answering Management Questions about Tidal Marsh Restoration Using Tidal Marsh Biosentinels Tidal Marsh Mudflat Goals Project 1999 #12;Goals Project 1999 South Baylands ~1800 Future1998 Tidal Marsh Mudflat #12;A8A8 South Bay Salt Pond Restoration Project WetlandTracker.org #12;Q1: How should

397

Tidally driven N, P, Fe and Mn exchanges in salt marsh sediments of Tagus estuary (SW Europe).  

PubMed

Short-sediment cores and flooding water were collected at 0, 5, 15, 25 and 50 min of tidal inundation in the two sites colonised by pure stands of Spartina maritima (low marsh) and Sarcocornia fruticosa (high marsh) from the Rosário salt marsh (Tagus estuary, SW Europe). Concentrations of NH(4)(+), NO(3)(-) + NO(2)(-) and HPO (4)(2-), Fe and Mn were measured in tidal flooding water and pore water. Flooding water is enriched in nutrients, particularly ammonium due to local discharge of untreated urban effluents. Nevertheless, NH(4)(+) and NO(3)(-) + NO(2)(-) concentrations in flooding waters at t = 5 min (NH(4)(+) = 246 ± 7 ?M, NO(3)(-) + NO(2)(-) = 138 ± 1 ?M for S. fruticosa and NH(4)(+) = 256 ± 8 ?M, NO(3)(-) + NO(2)(-) = 138 ± 1 ?M for S. maritima) rose sharply at both vegetated sites. An increase was also registered for HPO(4)(2-) and total dissolved Fe although the subsequent decrease was smoother. Advective transport induced by the two daily pulses of inundation is several orders of magnitude higher than the diffusive fluxes during submerged periods. In addition, solutes are exported from the sediment with the inundation and imported in submerged periods. The exported amount of inorganic nitrogen during tidal inundation (export of 3,200 ?mol N m(-2) day(-1)to the water column), is not counterbalanced by the sink of -290 ?mol N m(-2) day(-1) occurred during the submerged period. PMID:22086267

Caetano, M; Bernárdez, P; Santos-Echeandia, J; Prego, R; Vale, C

2012-11-01

398

Comparison of shallow-water and marsh-surface habitats associated with pipeline canals and natural channels in Louisiana salt marshes  

SciTech Connect

The primary objective of the study was to assess the effects of pipeline canals on the habitat function of inside-levee marshes. The degree to which inside-levee marshes function as nursery habitat for nekton residing in canals was examined by comparing densities of nekton on marshes adjacent to pipeline canals (inside-levee marshes) and natural tidal creeks. In addition, shallow subtidal habitats in the two environments (canals and natural channels) were compared by sampling nekton along the marsh edge at low tide and measuring predator encounter rates in both habitats.

Rozas, L.P.

1992-11-01

399

Salt-marsh reconstructions of relative sea-level change in the North Atlantic during the last 2000 years  

NASA Astrophysics Data System (ADS)

Sea-level changes record changes in the mass balance of ice sheets and mountain glaciers, as well as dynamic ocean-atmosphere processes. Unravelling the contribution of each of these mechanisms on Late Holocene timescales ideally requires observations from a number of sites on several coasts within one or more oceans. We present the first 2000 year-long continuous salt marsh-based reconstructions of relative sea-level (RSL) change from the eastern North Atlantic and uniquely from a slowly uplifting coastline. We develop three RSL histories from two sites in north west Scotland to test for regional changes in sea-level tendency (a positive tendency indicating an increase in the proximity of marine conditions and a negative tendency the reverse), whilst at the same time highlighting methodological issues, including the problems of dataset noise when applying transfer functions to fossil salt-marsh sequences. The records show that RSL has been stable (±0.4 m) during the last two millennia, and that the regional sea-level tendency has been negative throughout most of the record lengths. A recent switch in the biostratigraphy of all three records, indicating a regional positive tendency, means we cannot reject the hypothesis of a 20th century sea-level acceleration occurring in north west Scotland that must have exceeded the rate of background RSL fall (-0.4 mm yr-1), but this signal appears muted and later than recorded from the western North Atlantic.

Barlow, Natasha L. M.; Long, Antony J.; Saher, Margot H.; Gehrels, W. Roland; Garnett, Mark H.; Scaife, Rob G.

2014-09-01

400

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...

401

Primary productivity of emergent macrophytes in a Wisconsin freshwater marsh ecosystem  

Microsoft Academic Search

In 1972 primary production of various emergent macrophytes was examined in Theresa Marsh, a shallow, semimanaged impoundment in southeastern Wisconsin. Dominant macrophytes included Typha latifolia, Scirpus fluviatilis, Carex lacustris, Phalaris arundinacea and a shrub, Salix interior. Seasonal patterns of production as well as total production varied greatly among species. With estimates for litter loss and belowground production, annual net primary

J. M. Klopatek; F. W. Stearns

1978-01-01

402

Flow, Sedimentation, and Biomass Production on a Vegetated Salt Marsh in South Carolina  

E-print Network

studies at North Inlet estuary, South Carolina, the biomass of the S. alterniflora on the marsh platform is simply related to the time of submergence under tidally induced flows. Additionally, field data collected at North Inlet are used to relate biomass to plant area per unit volume, stem diameter, and an empirical

403

Studies on the production and decomposition of Spartina alterniflora Loisel. in a Galveston salt marsh  

E-print Network

(Table 1, p. 5 ). No one has tried to measure true produccion or find loss rates. But Texas does have extensive wetlands, with about 161, 000 ha of coastal marshes, 6/ of the U. S. total (James et al. 1972 cited in Turner and Gosselink 1975). A more...

Sears, Norman Evans

1981-01-01

404

Pressure change and surface expansion in salt marshes due to tidal inundation  

Microsoft Academic Search

Infiltration of water across the surface-water interface of a marsh in areas flooded due to tides has been known to cause swelling of sediments. The sudden tidal inundation in an unflooded soil creates a head gradient at the surface of the unsaturated soil above the water table. When water infiltrates into the soil under this gradient, the suction head in

M. Yavuz Corapcioglu; S. Mathur

1987-01-01

405

Uptake and distribution of N, P and heavy metals in three dominant salt marsh macrophytes from Yangtze River estuary, China.  

PubMed

We examined the variation in aboveground biomass accumulation and tissue concentrations of nitrogen (N), phosphorus (P), copper (Cu), zinc (Zn) and lead (Pb) in Phragmites australis (common reed), Spartina alterniflora (salt cordgrass), and Scirpus mariqueter throughout the growing season (April-October 2005), in order to determine the differences in net element accumulation and distribution between the three salt marsh macrophytes in the Yangtze River estuary, China. The aboveground biomass was significantly greater in the plots of S. alterniflora than in the plots of P. australis and S. mariqueter throughout the growing season (P<0.05). In August, the peak aboveground biomass was 1246+/-89 gDW/m(2), 2759+/-250 gDW/m(2) and 548+/-54 gDW/m(2) for P. australis, S. alterniflora and S. mariqueter, respectively. The concentrations of nutrients and heavy metals in plant tissues showed similar seasonal patterns. There was a steady decline in element concentrations of the aboveground tissues from April to October. Relative element concentrations in aboveground tissues were at a peak during the spring sampling intervals with minimum levels during the fall. But the concentrations of total nitrogen and total phosphorus in the belowground tissues were relatively constant throughout growing season. Generally, trace metal concentrations in the aboveground tissues of S. mariqueter was the highest throughout the growing season, and the metal concentrations of S. alterniflora tissues (aboveground and belowground) were greater than those of P. australis. Furthermore, the aboveground pools of nutrients and metals were consistently greater for S. alterniflora than for P. australis and S. mariqueter, which suggested that the rapid replacement of native P. australis and S. mariqueter with invasive S. alterniflora would significantly improve the magnitude of nutrient cycling and bioavailability of trace metals in the salt marsh and maybe transport more toxic metals into the water column and the detrital food web in the estuary. PMID:17306362

Quan, W M; Han, J D; Shen, A L; Ping, X Y; Qian, P L; Li, C J; Shi, L Y; Chen, Y Q

2007-07-01

406

Nutrient enrichment and precipitation changes do not enhance resiliency of salt marshes to sea level rise in the Northeastern U.S.  

EPA Science Inventory

In the U.S. Northeast, salt marshes are exceptionally vulnerable to the effects of accelerated sea level rise as compensatory mechanisms relying on positive feedbacks between inundation and sediment deposition are insufficient to counter inundation increases in low turbidity tida...

407

ESTIMATION OF BACTERIAL CELL NUMBERS IN HUMIC ACID-RICH SALT MARSH SEDIMENTS WITH PROBES DIRECTED TO 16S RIBOSOMAL DNA  

EPA Science Inventory

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 membr...

408

Effectiveness of the aquatic halophyte Sarcocornia perennis spp. perennis as a biotool for ecological restoration of metal-contaminated salt marshes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ecological restoration and creation of salt marshes is needed to compensate for their degradation and loss, but little is known about halophytes as plant biotools in restoration projects. Restoration plantings of halophytes have been established following eradication of invasive populations of the e...

409

1088 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 42, NO. 5, MAY 2004 Classification of Contamination in Salt Marsh Plants  

E-print Network

of Contamination in Salt Marsh Plants Using Hyperspectral Reflectance Machelle D. Wilson, Susan L. Ustin, Member.g., inaccessible areas, sites with potentially hazardous contamination, sites that need routine and frequent on the policy and eco- nomics of environmental monitoring for such industries as pe- troleum, chemical, waste

Rocke, David M.

410

Draft Genome Sequence of Bacillus sp. Strain NSP9.1, a Moderately Halophilic Bacterium Isolated from the Salt Marsh of the Great Rann of Kutch, India  

PubMed Central

We report the 4.52-Mbp draft genome sequence of Bacillus sp. strain NSP9.1, a moderately halophilic bacterium isolated from the salt marsh of the Great Rann of Kutch, India. Analysis of the genome of this organism will lead to a better understanding of the genes and metabolic pathways involved in imparting osmotolerance. PMID:24115550

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

2013-01-01

411

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. PMID:24356848

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

412

Measuring nutrient flux in Pacific Coast salt marshes using fluctuating water-level chambers  

EPA Science Inventory

Nutrient removal from the water column is an important ecosystem function that contributes to the production of clean water, a final valued ecosystem service of wetlands. However, little data is currently available for nutrient exchange in Pacific Northwest tidal ecosystems. We h...

413

Seed flotation and germination of salt marsh plants: The effects of stratification, salinity, and/or inundation regime  

USGS Publications Warehouse

We examined the effects of cold stratification and salinity on seed flotation of eight salt marsh species. Four of the eight species were tested for germination success under different stratification, salinity, and flooding conditions. Species were separated into two groups, four species received wet stratification and four dry stratification and fresh seeds of all species were tested for flotation and germination. Fresh seeds of seven out of eight species had flotation times independent of salinity, six of which had average flotation times of at least 50 d. Seeds of Spartina alterniflora and Spartina patens had the shortest flotation times, averaging 24 and 26 d, respectively. Following wet stratification, the flotation time of S. alterniflora seeds in higher salinity water (15 and 36 ppt) was reduced by over 75% and germination declined by more than 90%. Wet stratification reduced the flotation time of Distichlis spicata seeds in fresh water but increased seed germination from 2 to 16% in a fluctuating inundation regime. Fresh seeds of Iva frutescens and S. alternflora were capable of germination and therefore are non-dormant during dispersal. Fresh seeds of I. frutescens had similar germination to dry stratified seeds ranging 25-30%. Salinity reduced seed germination for all species except for S. alterniflora. A fluctuating inundation regime was important for seed germination of the low marsh species and for germination following cold stratification. The conditions that resulted in seeds sinking faster were similar to the conditions that resulted in higher germination for two of four species. ?? 2009 Elsevier B.V.

Elsey-Quirk, T.; Middleton, B.A.; Proffitt, C.E.

2009-01-01

414

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

NASA Technical Reports Server (NTRS)

An extensive pore water data set has been gathered in the Great Marsh, Delaware over various seasons, salinities, and tides. The data all point to a complimentary redox cycle for sulfur and iron which operates seasonally and tidally. Surface oxidizing conditions prevail in summer, with more reducing conditions at depth during the winter. During the spring tides which flood the marsh, pyrite oxidation occurs releasing excess dissolved iron (II) and sulfate to the porewaters, and precipitating authigenic solid iron phases. The redox conditions in the porewaters of the upper zone during the summer is poised between mildly oxidizing and mildly reducing conditions as shown by pE calculations. This redox environment and intermediate iron-sulfur redox species may be important for the stimulation of plant growth (photosynthesis) and sustenance of a viable microbial community (heterotrophy and chemoautropy).

Luther, George W., III; Church, Thomas M.

1987-01-01

415

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

SciTech Connect

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.

Faulds, James E.

2011-12-31

416

The Composition and Bioavailablity of Organic Matter Fractions Exported from a Salt Marsh of the Murderkill Estuary, Delaware, U.S.A  

NASA Astrophysics Data System (ADS)

Historically the Murderkill River, a tidal tributary of the Delaware Estuary, has had low dissolved oxygen concentrations, high nutrients, and high bacteria counts. Due to persistent water quality problems an extensive study was completed, revealing that salt marshes (and not agricultural or wastewater inputs) were the likely cause of the low oxygen concentrations. Stable isotopes and elemental ratio (C:N) results illustrate that the composition of dissolved, fine particulate, and coarse particulate organic matter in salt marsh water were not the same and thus could have different bioavailability, reactivity, and fate within the Murderkill. Therefore, our study focuses on how the connectivity to and inundation of salt marshes impact organic matter quality and cycling within the Murderkill River. Here we present a combination of high temporal resolution temperature, salinity, dissolved oxygen, nitrate, phosphate, chlorophyll, turbidity, and CDOM data obtained from the Kent County Land Ocean Biogeochemical Observatory (LOBO), discrete sampling over the tidal cycle, and 24 hour laboratory incubations of organic matter fractions. We use fluorescence excitation-emission matric (EEM) data and subsequent PARAFAC statistical analysis to assess the chemical nature of dissolved, particulate, and coarse particulate organic matter pools, how they vary over the tidal cycle, and modifications due to salt marsh input. Finally we examine how these fractions are related to oxygen consumption (as measured in laboratory bioassays). Preliminary results are in line with the stable isotopic and C:N data, suggesting that DOM pools within the Murderkill and those leaving the salt marsh are dominated by soil humics, while the particulate organic matter (POM) pools have greater contributions of protein-rich sources. In line with these chemical differences, results from dark short-term bioassays suggest that coarse and fine particulate organic matter pools are larger drivers of oxygen consumption than DOM pools. The greatest oxygen consumption rate was measured at the start of ebb tide and both oxygen consumption rates and saturation rates fell as the water exited the marsh. In addition to the decrease in water column oxygen concentrations and oxygen consumption rates, the organic matter pool became increasingly humic and likely more recalcitrant as low tide approached. Thus is appears that accurate estimation of oxygen demand from the salt marsh requires accounting for the dynamic but predictably variable turnover times of each of the major organic matter fractions.

Barnes, R. T.; Voynova, Y. G.; Ullman, W. J.; Sikes, E. L.; Aufdenkampe, A. K.

2013-12-01

417

Metal intracellular partitioning as a detoxification mechanism for mummichogs (Fundulus heteroclitus) living in metal-polluted salt marshes.  

PubMed

Intracellular partitioning of trace metals is critical to metal detoxification in aquatic organisms. In the present study, we assessed metal (Cd, Cu, Pb, and Zn) handling capacities of mummichogs (Fundulus heteroclitus) in metal-polluted salt marshes in New York, USA by examining metal intracellular partitioning. Despite the lack of differences in the whole body burdens, partitioning patterns of metals in intracellular components (heat-stable proteins, heat-denaturable proteins, organelles, and metal-rich granules) revealed clear differential metal handling capacities among the populations of mummichogs. In general, mummichogs living in metal-polluted sites stored a large amount of metals in detoxifying cellular components, particularly metal-rich granules (MRG). Moreover, only metals associated with MRG were consistently correlated with variations in the whole body burdens. These findings suggest that metal detoxification through intracellular partitioning, particularly the sequestration to MRG, may have important implications for metal tolerance of mummichogs living in chronically metal-polluted habitats. PMID:19853291

Goto, Daisuke; Wallace, William G

2010-04-01

418

Effects of dispersant used for oil spill remediation on nitrogen cycling in Louisiana coastal salt marsh soil.  

PubMed

On April 20, 2010, the BP Deepwater Horizon (DWH) offshore oil platform experienced an explosion which triggered the largest marine oil spill in US history. Approximately 7.9millionliters of dispersant, Corexit EC9500A, was used during the spill between May 15th and July 12th. Marsh soil samples were collected from an unimpacted marsh site proximal to coastal areas that suffered light to heavy oiling for a laboratory evaluation to determine the effect of Corexit on the wetland soil microbial biomass as well as N-mineralization and denitrification rates. Microbial biomass nitrogen (N) values were below detection for the 1:10, 1:100 and 1:1000 Corexit:wet soil treatments. The potentially mineralizable N (PMN) rate correlated with microbial biomass with significantly lower rates for the 1:10 and 1:100 Corexit:wet soil additions. Potential denitrification rates for Corexit:wet soil ratios after immediate dispersant exposure were below detection for the 1:10 treatment, while the 1:100 was 7.6±2.7% of the control and the 1:1000 was 33±4.3% of the control. The 1:10000 treatment was not significantly different from the control. Denitrification rates measured after 2weeks exposure to the surfactant found the 1:10 treatment still below detection limit and the 1:100 ratio was 12±2.6% of the control. Results from this lab study suggest that chemical dispersants have the potential to negatively affect the wetland soil microbial biomass and resultant microbial activity. Consequences of exposure led to reductions in several important microbial-regulated ecosystem services including water quality improvement (denitrification) and ecosystem primary productivity (N-mineralization). Future studies should investigate the longer-term impacts of dispersant exposure on the microbial consortia to determine if microbial activity recovers over time. PMID:25123788

Pietroski, Jason P; White, John R; DeLaune, Ronald D

2015-01-01

419

Salt marsh sediment characteristics as key regulators on the efficiency of hydrocarbons bioremediation by Juncus maritimus rhizospheric bacterial community.  

PubMed

Mitigation of petroleum hydrocarbons was investigated during a 5-month greenhouse experiment, to assess the rhizoremediation (RR) potential in sediments with different characteristics colonized by Juncus maritimus, a salt marsh plant commonly found in temperate estuaries. Furthermore, the efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms, was tested in combination with RR. The effect of the distinct treatments on hydrocarbon degradation, root biomass weight, and bacterial community structure was assessed. Our result showed higher potential for hydrocarbon degradation (evaluated by total petroleum hydrocarbon analysis) in coarse rhizosediments with low organic matter (OM), than rhizosediments with high OM, and small size particles. Moreover, the bacterial community structure was shaped according to the rhizosediment characteristics, highlighting the importance of specific microbe-particle associations to define the structure of rhizospheric bacterial communities, rather than external factors, such as hydrocarbon contamination or the applied treatments. The potential for hydrocarbon RR seems to depend on root system development and bacterial diversity, since biodegradation efficiencies were positively related with these two parameters. Treatments with higher root biomass, and concomitantly with higher bacterial diversity yielded higher hydrocarbon degradation. Moreover, BS and BA did not enhance hydrocarbons RR. In fact, it was observed that higher nutrient availability might interfere with root growth and negatively influence hydrocarbon degradation performance. Therefore, our results suggested that to conduct appropriate hydrocarbon bioremediation strategies, the effect of sediment characteristics on root growth/exploration should be taken into consideration, a feature not explored in previous studies. Furthermore, strategies aiming for the recovery of bacterial diversity after oil spills may improve the efficiency of hydrocarbon biodegradation in contaminated salt marsh sediments. PMID:25081009

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

2015-01-01

420

LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination  

NASA Astrophysics Data System (ADS)

This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. 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 to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

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

2010-06-01

421

Prokaryotes in salt marsh sediments of Ria de Aveiro: Effects of halophyte vegetation on abundance and diversity  

NASA Astrophysics Data System (ADS)

The aim of this study was to investigate the influence of monospecific colonization of sediment stands by Spartina maritima or Halimione portulacoides on benthic prokaryote assemblages in a salt marsh located in Ria de Aveiro (Portugal). The distribution of Bacteria, Archaea and sulfate-reducing bacteria (SRB) in sediments with monospecific plant stands and in unvegetated sediments was characterized by Fluorescence In Situ Hybridization (FISH). Total prokaryote abundance (0.4 × 109-1.7 × 109 cells gdw-1) was highest in sediments from the surface layer. The domain Bacteria comprised approximately 40% of total prokaryote communities with the highest percentages occurring in the surface layer. Archaeal cells corresponded to an average of 25% of total prokaryote population, with higher abundance in the vegetation banks, and displaying homogeneous vertical distribution. The relative abundance of SRB represented approximately 3% of total 4', 6-diamidino-2-phenylindole dihydrochloride (DAPI) stained cells at unvegetated sediment and H. portulacoides stand and 7% at S. maritima stand. Headspace solid-phase microextraction (HS-SPME) combined with Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GC × GC-ToFMS) was used to analyse the volatile and semi-volatile fraction of root exudates. A total of 171 compounds were identified and Principal Component Analysis showed a clear separation between the chemical composition (volatile and semi-volatile organic compounds) of the exudates of the two plants. The patterns of vertical distribution and differences in the proportion of SRB and Archaea in the prokaryote communities developing in sediments colonized by Spartina maritima or Halimione portulacoides suggest the existence of plant-specific interactions between halophyte vegetation and estuarine sediment bacteria in Ria de Aveiro salt marshes, exerted via sediment lithology and root-derived exudates.

Oliveira, Vanessa; Santos, Ana L.; Aguiar, Claúdia; Santos, Luisa; Salvador, Ângelo C.; Gomes, Newton C. M.; Silva, Helena; Rocha, Sílvia M.; Almeida, Adelaide; Cunha, Ângela

2012-09-01

422

Seasonal Dynamics of Trace Elements in Tidal Salt Marsh Soils as Affected by the Flow-Sediment Regulation Regime  

PubMed Central

Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering. PMID:25216278

Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K. Ramesh

2014-01-01

423

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

424

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