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The photosynthetic productivity of the intertidal communities dominated by the seagrass Zostera noltii and the cordgrass Spartina maritima was assessed in two contrasting situations during a tidal cycle, i.e., air exposure and water immersion. Two complementary methods were used: infra red gas analysis of CO2 flux measurements in whole communities and chlorophyll a fluorescence measurements of individual plants photosynthetic activity. Higher photosynthetic rates of Z. noltii in air were observed both at the individual plants response level determined by chlorophyll fluorescence and at the community level measured as gas exchange (CO2 uptake). S. maritima plants consistently showed low photosynthetic response when immersed. Gross community production (GCP) measured as carbon dioxide uptake was always higher in air than in water for both communities. When immersed, the GCP of both communities was similar. However, when exposed to the air, the GCP of the S. maritima community was higher than the one of Z. noltii's. The key factor in CO2 assimilation by air-exposed Z. noltii was the retention of water in sediment microdepressions. During low tide, depressions in the sediment retain a considerable amount of water, enough to maintain leaf hydration. In these conditions, rapid air-water CO2 diffusion occurs, making it readily available to plants. The community gas exchange measurements compared well with the fluorescence indications. Both Z. noltii and S. maritima were shown to be responsible for the overall pattern of photosynthetic carbon fixation within their respective communities, both during submersion and emersion periods. The short-term incubations method described in this report proved to be a valuable tool for field measurements of intertidal lagoon productivity. It provides fast and precise values of carbon dioxide fixation, both in submerged and air-exposed communities. © 2004 Elsevier B.V. All rights reserved.

Spartina maritima is a salt-marsh species from European and African Atlantic coasts. In the northern range of the species (including north-west France), a rapid decline of the populations has been observed during the 20th century. In this paper, the molecular diversity of 10 populations of S. maritima from France has been investigated using nuclear and chloroplast DNA markers: inter-simple sequence polymorphism (ISSR), randomly amplified polymorphic DNA (RAPD), inter-retrotransposon amplified polymorphism (IRAP), and PCR-RFLP of a 5 kb long portion of chloroplast DNA. The results reveal an extremely low level of genetic variation in this species: only one nuclear marker (out of 98) was polymorphic, with the presence of two genotypes randomly distributed among the populations. The lack of genetic diversity is interpreted in light of the almost exclusive vegetative propagation of the species in its northern range, the colonization history of the populations, and the origin of S. maritima (2n = 60) in the hexaploid lineage of the genus and in the context of the management of S. maritima populations.

The stability of cohesive and non-cohesive sediments in a mixed intertidal habitat within the Ria Formosa tidal lagoon, Portugal, was examined during two field campaigns as part of the EU F-ECTS project. The cohesive strength meter Mk III was used to determine critical erosion shear stress (τc) within a variety of different intertidal habitats and substrata, including Spartina maritima fields and Zostera noltii beds. The best predictor(s) for τc were derived from a range of properties measured for the surface sediments (chlorophyll a, colloidal carbohydrate, water, organic content, % fraction

Spatial and temporal diversity of food sources of intertidal nematodes of 3 different feeding habitats (estuarine muddy sediments, Spartina maritima and Juncus maritimus marshes) in the Roscoff Aber Bay, France, was assessed by the use of δ 13 C and δ 15 N values. Within the bay, nema- todes largely dominated within the total meiofauna. Throughout the 3 sampling periods, the δ 13 C and δ 15 N values for nematodes and sources showed that the dominant sedimentary organic matter sources within the 3 microhabitats considered, namely terrigeneous inputs, detrital Spartina mar- itima or Juncus maritimus and marine POM, did not contribute a significant part of the diet to locally occurring nematodes. In fact, the δ 13 C and δ 15 N values indicate that organic matter derived from stranded macroalgae, mostly Enteromorpha sp. and Fucus spiralis, was the primary contributor to the assimilated food sources of nematodes; more readily utilisable sources (i.e. benthic diatoms) are virtu- ally absent. The present work provides evidence that detrital pathways, including stranded macroal- gae from nearby rocks and free-living nematodes, play a key role in the trophic ecology of intertidal flat areas.

The composition of interstitial water collected from a salt marsh in NW Spain showed clear seasonal and spatial variations associated with redox cycles of Fe and S. In the summer, salinity increased in all soils as a consequence of the increase in evapotranspiration. The pH and concentrations of heavy metals also differed with season, but not all environments showed the same variations. Soils not colonized by plants had the highest pH and lowest heavy metal concentrations in the summer. These results support the idea that higher temperatures lead to an increase in the activity of sulfate-reducing bacteria, which in turn leads to an increase in alkalinity and concentration of sulfides in the water. Trace metals tend to precipitate with sulfides under these conditions and are removed from the interstitial water. In contrast, in the soils colonized by Spartina maritima, the oxidation of metal sulfides during the summer led to a decrease in pH and an increase in the metal concentrations in the interstitial water. The results obtained concur with those found for seasonal variations in metal sulfides in soils from the same salt marsh.

Wetland loss in many estuaries around the world, has been attributed mainly to undermining and collapse of channel banks. This study aims to quantify bank erosion and vertical erosion/accretion rates on intertidal sediments in the Odiel tidal marshes (SW Spain). Bi-monthly erosion/accretion measurements were taken on eight channels over a four year period, using markers (iron stakes) located on intertidal areas and on eroding banks. The intensity of erosion divides the Odiel marshes into two zones. The northern zone has low erosion rates (horizontal erosion c. -20 cm year -1 and vertical erosion / accretion between 0 and ‐1 cm year -1 ), and coincides with low levels of human activities. The southern zone has higher erosion rates (horizontal erosion c. -25 cm year -1 and vertical erosion / accretion between 0 and ‐5 cm year-1) and exhibits higher levels of anthropogenic pressure. The highest horizontal and vertical erosion rates (c. -80 cm year-1) were recorded on navigation channels. Horizontal and vertical erosion showed a positive linear relationship (r 2 = 0.66; P< 0.01), indicating that sediments mobilized by bank erosion are not deposited on adjacent intertidal areas. Erosion led to mature marsh habitat loss of c. 17000 m2 year-1 and a sediment mobilization of c. 16500 m3 year -1.

Curado, G.; Rubio-Casal, A.E.; Figueroa, E., and Castillo, J.M., 2014. Plant zonation in restored, nonrestored, and preserved Spartina maritima salt marshes. Journal of Coastal Research, 30(3), 629–634. Coconut Creek (Florida), ISSN 0749-0208. This study analyzes the vegetation zonation and the abiotic environment (sediment elevation, pH, redox potential, and electrical conductivity) 2.5 years after salt marsh restoration using Spartina maritima and Sarcocornia perennis plantations in the Odiel Marshes (SW Iberian Peninsula) in comparison with preserved and degraded marshes. Restored marshes presented higher species richness (10 spp.) than nonrestored (6 spp.) and preserved (3 spp.) marshes, as a result of milder abiotic conditions (more oxygenated sediments than preserved marshes) and higher habitat diversity (sandy patches at higher elevations). Marshes restored using S. maritima (planted at a density of 1 clump m � 2 ) achieved a similar relative cover to preserved marshes (ca. 50%) 2.5 years after transplanting. Spartina maritima showed higher tiller height in preserved (40 6 2 cm) than in restored marshes (34 6 1c m).Sarcocornia perennis cover was similar in the three areas, being concentrated at higher elevations in the tidal gradient. Our results show the success from the point of view of vegetation of restoring European low salt marshes using S. maritima and S. perennis plantations, since they are able to reproduce, 2.5 years after restoration, the typical zonation pattern.

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.

Se ha detectado un patrón estacional en la dinámica sedimentaria en zonas de marisma baja, relacionado con la distribución anual de las precipitaciones característica del clima mediterráneo, que induce cambios en el caudal de los ríos y en la cantidad y distribución de los aportes de partículas finas que entran en el estuario. En este escenario se pone de manifiesto cómo la presencia de vegetación (Spartina maritima) favorece la acreción y estabilización de sedimentos. En planicies desprovistas de vegetación, los mayores niveles de acreción se registran durante primavera y principios de verano. Las lluvias otoñales determinan un aumento del caudal de los ríos, con un incremento en el aporte de sedimentos y removilización de éstos en las zonas desnudas. Parte de estos sedimentos quedarán entonces retenidos en las zonas provistas de vegetación. Durante este periodo de otoño es cuando esta vegetación alcanza sus mayores valores de biomasa, maximizando así su papel como estabilizador de sedimentos. We have found a seasonal pattern operating on the lower areas of a tidal marsh, in relation to the characteristic annual distribution of the rainfall in a Mediterranean climate which induces changes in river flows and in quantity and distribution of loam sediments entering the estuary. Also, the presence of vegetation (S. maritima) favours the accretion rate and the sediment stabilization. Bare muds record the maximum values of accretion during Spring and early Summer. Autumn rainfalls increase the river flow what means a new input of sediments and the movilization of the old ones from the bare muds; the vegetation raises the maximum biomass and it traps and stabilizes these sediments. Dirección General de Investigación Científica y Técnica. Gobierno de España-PB94-1455

Heavy metal concentrations present in the above- and beowground tissues of Scirpus maritimus L., Spartina maritima (Curtis) Fernald and Zostera noltii Hornem were analysed seasonally in the Mondego Estuary, Portugal. The sediments of the estuary were confirmed to contain only low concentrations of heavy metals. The belowground tissues of all three species showed higher heavy metal concentrations than the aboveground tissues. Although the sediments only contained low levels of contamination, because the area occupied by S. maritimus and Z. noltii was large, significant quantities of heavy metals were accumulated and exported to the surrounding water bodies. In contrast with observations of highly contaminated estuaries, it was found that in spite of the low level of contaminants in the sediments of the Mondego Estuary, aquatic vegetation functioned as a source of metals for nearby systems. The authors would like to thank to the ‘Fundação para a Ciência e Tecnologia (FCT)’ for funding the research in the Centre of Oceanography throughout the project PEst-OE/MAR/UI0199/2011 and in the Institute of Marine research (IMAR) throughout the project PEst-C/MAR/UI0284/2011 and this specific work throughout the project 3M RECITAL (LTER/BIA-BEC/0019/2009). T. Couto investigation was supported by FCTthroughout a PhD grant (SFRH/ BD/64608/2009).

Publisher Summary This chapter describes the origin, variation, and spread of the salt marsh grass Spartina anglica, and presents new material relating to its ecology and evolution. Using electrophoretically detectable variation, the strong circumstantial evidence is confirmed that S. anglica originated by chromosome doubling of the sterile hybrid between the Old World species Spartina maritima and the North American Spartina alterniflora. The extensive analysis of isoenzyme and seed protein phenotypes indicates that S. anglica is lacking in genetic variation. S. anglica is among temperate grasses––a C4 species. The species interaction with other species discusses the effects of S. anglica invasion on aerial and benthic invertebrates and on overwintering wading birds––Calidris alpine. Soil conditions, grazing and temperature are important factors affecting the competitive interaction. The consequences of the genetic bottleneck that occurred during the speciation process and the relative youth of S. anglica in evolutionary terms are emphasized by comparing the species with P. maritima. The greater variation, population differentiation and niche breadth of the species are evident. The changes which occur with global warming and rising sea levels and the affect of the species' evolution are also reviewed.

1 The construction of a raised dike across the coastal saltmarshes of Odiel (Huelva, south-west Spain) in 1977 divided a uniform area of low-lying sediment into two lagoons with very different drainage properties. To the east of the dike, there is rapid drainage into the estuarine channel of the Odiel and Tinto rivers, whereas to the west, the development of sand spits has impeded drainage such that standing water persists long after high tides, despite the slightly higher elevation of this area. 2 Both lagoons have been colonized by isolated clones of Spartina maritima, which have locally enhanced accretion to form domed tussocks (`nucleation'). The diameter of the tussocks was highly correlated with the elevation of their sediment surface, the larger tussocks having been the earlier colonists in a generally accreting system. Spartina in the interior of the tussocks showed reduced tiller density and vigour. 3 Only in the better-drained lagoon have the central, higher areas of the Spartina tussocks been invaded by Arthrocnemum perenne, although seed is freely available in both lagoons. Arthrocnemum formed a sprawling, dense canopy and a superficial, relatively impenetrable root system; it rapidly suppressed the remaining tillers of Spartina, eventually leaving only a fringe around the edge of the tussock. Areas invaded by Arthrocnemum were characterized by a superficial layer (10 cm) of oxidizing sediment $(E_h > + 80 mV)$. Spartina-dominated areas in both lagoons remained highly reducing, even in the surface layers ($E_h < - 150 mV$). 4 In terms of successional mechanisms, primary colonization by Spartina maritima facilitates the invasion by Arthrocnemum, which only becomes established from seed on relatively well-drained, oxidising sediments. The interaction is, however, more complicated than this: declining tiller density within the tussocks prior to invasion by Arthrocnemum is consistent with an inhibition mechanism, and the superior competitive ability of Arthrocnemum, once established, suggests that a tolerance mechanism may also operate.

Net aerial production of Spartina maritima (Curtis) Fernald, in a warm temperature estuary in Algoa Bay, South Africa, occurring possibly as an exotic, was estimated as 523–680 g dry weight m−2 year−1. The method of production measurement designed here used community structure data and accounted for the species' extremely slow shoot production (3.1–6.7 dry g m−2 year−1) and continuous leaf turnover (516–676 dry g m−2 year−1). Standard methods of production measurement for other Spartina species failed by not accounting for the non-seasonal growth of S. maritima. N, C, organic and energy content of live and dead shoots remained constant through the seasons. The P : B ratio is 1.1, which is lower than for other Spartina species, but agrees with the low vigour shown by negligible regrowth a year after clipping. Decomposition rates were 90 mg g−1 month−1 in winter and 305 mg g−1 month−1 in summer. Monthly decomposition values showed significant correlation with air temperature (r = 0.86; P < 0.01), and water temperature (r = 0.80; P < 0.01), suggesting that monthly litterbag losses are a valid means of determining decomposition rate.

The spatial patterns of N fixation in the salt marshes of the Swartkops estuary, Republic of South Africa, were established by investigating acetylene reduction activity (ARA) along four environmental gradients. Most sites investigated showed high levels of ARA. Surface sediment and rhizosphere ARA were mainly found in the middle regions of the intertidal which correlate with high organic C and moisture levels. Activity along Spartina maritima tillers showed > 98% restricted to the stem region. The Spartinetum community was the major contributor of fixed N to the salt marsh and appears to be responsible for the marsh acting as an exporter of N to Algoa Bay, Republic of South Africa.

Constructed Wetlands (CWs) can be a valuable technology to treat high salinity wastewaters but it is not known their potential for removal of both nutrients and salt, and the type of plants to use. This study evaluated the effect of three plants on salt reduction and simultaneous nutrient removal in CWs microcosms with expanded clay and in hydroponic conditions. Initial values of the synthetic wastewater tested were EC = 15 dS m− 1, SAR = 151; NH4 +-N = 24 mg L− 1; PO4 3 −-P = 30 mg L− 1 and NO3 −-N = 34 mg L− 1. With expanded clay CW removal efficiency for NH4 +-N was 21, 88 and 85%, while for NO3 –-N, it was 4, 56 and 68% for Spartina maritima, Juncus maritimus and Arundo donax, respectively. PO4 3–-P was adsorbed completely in the expanded clay. However, in hydroponic system, removal efficiencies for NH4 +-N were 53 and 50%, while PO4 3–-P removal was 89 and − 14% for Spartina maritima and Juncus maritimus, respectively. Nutrient removal in planted microcosms was statistically higher than unplanted controls for NH4 +-N and PO4 3 −-P. However, salt removal was apparent in the hydroponic system only after 23 days of HRT, despite clear salt excretion visible in both Spartina maritima and Juncus maritimus. This study demonstrates the potential of two halophytic plants for saline wastewater treatment. However, salt removal in such a scenario could not be well documented and might prove to be impractical in future work. © 2016 Elsevier The authors would like to acknowledge the Portuguese Science and Technology Foundation (FCT) for the PhD grant (FCT - DFRH - SFRH/BD/84750/2012).

A small artificial wetland was constructed through which intake water flowed before entering the initial pond of a solar saltworks. This trial wetland was designed for the removal of excessive nutrients from the water as the system is becoming hypertrophic. Spartina maritima (Curtis) Fernald was the dominant halophytic grass used in the wetland and Ulva rigida C. Agardh the dominant macroalga. The nutrient content of the inflow and outflow water of the wetland was monitored for eight months after construction. For seven out of nine analyses, the ammonium concentrations of water flowing out of the wetland were significantly reduced (by an average of 56%) when compared to those measured in water flowing into the wetland. Nitrate and phosphate concentrations for eight out of nine analyses also showed significant reductions (by 60% and 56% respectively). The success of this wetland indicates that it can be an effective management tool for nutrient reduction in solar saltworks.

Spartina marshes, comprising four species (Mobeley, 1956), occur along the Atlantic coasts of North and South America, from Nova Scotia to Argentina. Distribution is discontinuous, with the greatest interruption associated with the mangrove jungle of the Amazon River delta. Recently, Eleuterius and Meyers (1974) found that three of these marsh grass species were regular hosts for the ergot fungus Claviceps purpurea (Fr.) Tul. In 1966, Samuelson and Gjerstad proposed to separate as a new species, Claviceps maritima, the "feather ergot" parasitizing a Spartina species from the coast of Argentina. The basis for this separation was the consistent and usually high (0.78%) total alkaloid content compared with that of 0.15% recorded in most pharmacopeias. The specific name proposed for the ergot was that of the host plant, believed to be Spartina maritima (Curt.) Fern., although accurate identification was uncertain. Our investigation, based on the monograph of the genus Spartina by Mobeley (1956) and a floristic survey of the Argentine coast by Cabrera (1970), indicates that the host species was probably Spartina alterniflora Loisel. Furthermore, Spartina maritima is restricted to the old world.

The determination of trace metals in aquatic environments have received particular attention, due to the large “inputs” of heavy metals and other residual elements as a consequence of the high degree of industrialization and urbanization.

This paper contains a survey of ecological and phytocoenological investigations on maritime vegetation, carried out in the SW Netherlands. After an outline of the nature of the Dutch coasts and of former investigations on salt-marsh vegetation, special attention is devoted to a cybernetic approach to this vegetation and its habitat as realizations in space and time. From an ecological point of view stability and instability in the environment appears to be of essential importance. Starting from this approach estuarine phenomena, the genesis of salt marshes and different physical and chemical properties of the soil (texture, carbonate contents, soil-water relations, salinity and supply of organic matter) are discussed, as well as their connections with some features of the vegetation. Using the same strain of thought, a survey of the vegetation is given, at the same time starting from the principles of classification according to the French-Swiss School of Braun-Blanquet.

The roots of the vascular plant Spartina maritima, growing in the saltmarshes of the Tagus Estuary, Portugal, are surrounded by tubular concretions whose diameter can reach >0.2 cm. Concretions are also found scattered within the sediment matrix in and below the root zone. The concretions comprise 4% (DW) of the sediment and contain 11.7 2 1.6% iron compared to 4.9 -C 0.3% iron in the sediment in which they are found. They are formed by the precipitation of iron oxides in the pores between the sediment grains; this has filled about one-sixth of the originally available pore space. To produce the concretions, the plants have extracted 0.25% Fe from the anoxic bulk sediment and concentrated it into the oxidized microenvironment surrounding each root. A mass-balance model using cylindrical geometry shows that the observed concretion density can be produced by a network of roots with l-cm spacing. The space between the roots limits the amount of Fe that is available to a given root and thus determines the size of the individual concretion. Field observations and mathematical modeling show that plants can produce concretions on their roots in the space of a few weeks. The rhizoconcretions are 5-10 times enriched in Cd, Cu, Pb, and Zn with respect to the sediment surrounding them, and the smaller diameter concretions are more enriched than the larger ones. The preferential enrichment of the smaller diameter concretions, which was not observed for Fe and Mn, is independent of depth in the sediment for Cd and Cu; however, for Zn and Pb, the preferential enrichment is most pronounced within the upper trace metal-contaminated sediment layer. The rhizoconcretions have acquired their load of metals via diffusion from the surrounding sediment. In the case of Fe and Mn, the concentration gradient that drives the diffusion is maintained by the precipitation of insoluble oxides. In the case of Cd, Cu, Zn, and Pb, the mechanism that maintains a concentration gradient toward the surface of the root is not know, but our data show that S. maritima is capable of mobilizing trace metals dispersed in reducing anoxic estuarine sediment and concentrating them into the distinct oxidized microenvironments that surround the roots.

Sediment cores were collected from two sites of the Tagus estuary salt marshes which differed in degree of metal contamination. At each site, six 60-cm-long cores were taken, three from a non-vegetated intertidal zone, and one from each of areas colonized by salt marsh plants, Spartina maritima, Halimione portulacoides and Arthrocnemum fruticosum, respectively. Total concentrations and concentrations in sequential extractions of Zn, Pb, and Cu were determined in several sediment layers. Sediment slices containing most of the roots (5–15-cm depth) were enriched in metals in comparison with other depths in the core and with non-vegetated cores. Additionally, metals in sediment slices with roots were preferentially linked to the residual fraction. These results are evidence that aquatic plant roots can have a strong influence on metal concentration and speciation in sediments. Since metals become immobilized in vegetated sediments, the preservation of salt marshes or the creation of artificial wetlands could be considered as an efficient natural means for maintaining ecosystem health or restoring ecosystem quality.

ACESSO via B-on: http://dx.doi.org/ 10.1007/s00572-001-0137-6, The factors which may influence temporal and spatial variation in plant arbuscular mycorrhizal (AM) colonization and propagule occurrence were evaluated in a Portuguese salt marsh poor in plant diversity. Two distinct sites were studied: a more-flooded (low marsh) and a less-flooded zone (high marsh). AM root colonization, AM fungal spore number and inoculum potential, soil edaphic parameters and tidal flooding time periods were analysed. Levels of AM colonization were considerable in Aster tripolium and Inula crithmoides but very low in Puccinellia maritima and non-existent in Spartina maritima, Halimione portulacoides, Arthrocnemum fruticosum and Arthrocnemum perenne. Fungal diversity was very low, with Glomus geosporum dominant at both marsh zones. Colonization showed no spatial variation within marsh zones but temporal variation was observed in the high marsh, dependent on plant phenological phases. In the low marsh, no significantly seasonal variation was observed. Apparently, plant phenological events were diluted by stressful conditions (e.g. flooding, salinity). Spore density was significantly different between marsh zones and showed temporal variation in both zones. This study showed that distribution of mycorrhizas in salt marsh is more dependent on host plant species than on environmental stresses.