Brackish Water Marsh Research Articles

Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh

Abstract Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons. Overall, 78% of ducklings died and 84% of mortalities occurred < 7 days after hatch. After hatching in upland fields, survival was greater for broods that hatched closer to flooded wetlands; broods had a ≥ 75% chance of surviving the move from the nest to water when nests were located ≤ 140 m from the nearest wetland and ≤ 50% chance of surviving when nests were located ≥ 970 m from the nearest wetland. Predation accounted for 91% of mortalities and was attributed to mammals (27.6%), birds (22.0%), snakes (4.4%), and unknown predators (46.0%). Anas platyrhynchos survival to fledging (54 days) was only 3.2% and 0.9% during 2 drier years and 11.7% and 16.7% during 2 wetter years. Mareca strepera survival to fledging was 9.4% to 11.2% among years. Daily survival rates for ducklings generally increased with the amount of flooded wetlands within 0.5 km (A. platyrhynchos) and 1.0 km (M. strepera) of the nest at hatch. Additionally, survival rates increased with duckling age and body mass at hatch for both species and decreased with hatch date for A. platyrhynchos but not M. strepera, which may be partially due to the earlier onset of A. platyrhynchos nesting. For ducklings that survived the initial move to water, survival rates were negatively correlated with salinity and this effect was more pronounced for younger ducklings. Anas platyrhynchos survival to 7 days post hatch decreased by 9.1% (wetter year) to 31.4% (drier year) when ducklings were in 12 ppt water (99th quantile of cumulative salinity concentrations experienced by ducklings) versus 0.5 ppt water. Mareca strepera survival to 7 days decreased by 7.4% when ducklings were in 12 ppt vs. 0.5 ppt water. Our results suggest that maintaining a network of low salinity wetlands within 1 km of upland nesting sites would likely improve duckling survival rates, especially during the critical 7-day period after hatch.

Risk Assessment of Oil Spills along the Coastline of Jiaozhou Bay Using GIS Techniques and the MEDSLIK-II Model

With the increasing global reliance on maritime oil transportation, oil spills pose significant environmental hazards to coastal ecosystems. This study presents a comprehensive quantitative framework for assessing oil spill risks along the Jiaozhou Bay coastline in China. The research begins with an analysis of historical spill data to construct representative oil spill simulation scenarios. The advanced MEDSLIK-II oil spill prediction model is then employed to simulate oil spill trajectories under these scenarios, focusing on key parameters such as oil thickness and mass to evaluate the hazard levels associated with each scenario. Subsequently, the Environmental Sensitivity Index (ESI) is utilized to assess the vulnerability of coastal zones, while Geographic Information System (GIS) techniques are employed for a spatial analysis and visualization of the results. The case study, covering a 26.87 km stretch of the Jiaozhou Bay coastline, reveals 10 high-risk zones with a total length of 8561.2 m. These areas are predominantly characterized by saltwater marshes, brackish water marshes, and inundated low-lying areas, with ESI rankings of 9 and 10, accounting for 24% of the 339 analyzed segments. The modeling results indicate that in the simulated scenarios, oil spills originating from the Huangdao Oil Port and Qianwan Port pose the greatest risks, with potential impacts extending up to 12 km and 15 km along the coastline, respectively. The study highlights the importance of considering multiple factors, including oil spill trajectories, coastal geomorphology, and ecological sensitivity, in comprehensive risk assessments. The proposed framework demonstrates potential for adaptation and application to other coastal regions facing similar oil spill risks, contributing to the advancement of coastal management practices worldwide.

Modeling net ecosystem carbon balance and loss in coastal wetlands exposed to sea-level rise and saltwater intrusion.

Coastal wetlands are globally important stores of carbon (C). However, accelerated sea-level rise (SLR), increased saltwater intrusion, and modified freshwater discharge can contribute to the collapse of peat marshes, converting coastal peatlands into open water. Applying results from multiple experiments from sawgrass (Cladium jamaicense)-dominated freshwater and brackish water marshes in the Florida Coastal Everglades, we developed a system-level mechanistic peat elevation model (EvPEM). We applied the model to simulate net ecosystem C balance (NECB) and peat elevation in response to elevated salinity under inundation and drought exposure. Using a mass C balance approach, we estimated net gain in C and corresponding export of aquatic fluxes ( ) in the freshwater marsh under ambient conditions (NECB=1119 ± 229 gC m-2 year-1 ; FAQ =317 ± 186 gC m-2 year-1 ). In contrast, the brackish water marsh exhibited substantial peat loss and aquatic C export with ambient (NECB=-366 ± 15 gC m-2 year-1 ; FAQ =311 ± 30 gC m-2 year-1 ) and elevated salinity (NECB=-594 ± 94 gC m-2 year-1 ; FAQ =729 ± 142 gC m-2 year-1 ) under extended exposed conditions. Further, mass balance suggests a considerable decline in soil C and corresponding elevation loss with elevated salinity and seasonal dry-down. Applying EvPEM, we developed critical marsh net primary productivity (NPP) thresholds as a function of salinity to simulate accumulating, steady-state, and collapsing peat elevations. The optimization showed that ~150-1070 gC m-2 year-1 NPP could support a stable peat elevation (elevation change≈SLR), with the corresponding salinity ranging from 1 to 20 ppt under increasing inundation levels. The C budgeting and modeling illustrate the impacts of saltwater intrusion, inundation, and seasonal dry-down and reduce uncertainties in understanding the fate of coastal peat wetlands with SLR and freshwater restoration. The modeling results provide management targets for hydrologic restoration based on the ecological conditions needed to reduce the vulnerability of the Everglades' peat marshes to collapse. The approach can be extended to other coastal peatlands to quantify C loss and improve understanding of the influence of the biological controls on wetland C storage changes for coastal management.

Eemian to Early Weichselian regional and local vegetation development and sedimentary and geomorphological controls, Amersfoort Basin, The Netherlands

Abstract Two new records from the Amersfoort glacial basin are investigated by means of pollen analysis. The cores are situated in the deeper part, close to the original Eemian stratotype Amersfoort 1 (Zagwijn, 1961) and at the margin of the basin. The aim is to reconstruct the Eemian and Early Weichselian vegetation development and to explore the impact of accommodation space, influx of allochthonous pollen and geomorphology on the vegetation composition. The results of the Amersfoort Basin are compared to the current Eemian stratotype in the Amsterdam Basin and other Eemian sites in the Netherlands. An almost complete Eemian to Early Weichselian sequence (E2-EWII) was retrieved from the deeper part of the Amersfoort basin. The late Saalian (LS) to early Eemian transition is not recorded in the Amersfoort basin, in contrast to the deeper Amsterdam Basin. The basin marginal core Den Treek reveals a condensed late Eemian (E5-6) and Early Weichselian (EW I-II) succession showing the importance of accommodation space. The first impact of the Eemian transgression is registered at the E3 to E4a boundary in the Amersfoort and Amsterdam basins, and highest sea level is proposed at the end of pollen zone E5. Upstream in the Eemian delta, in the palaeo-Vecht valley and IJssel Basin, the transgression is recorded later. The influx of reworked (allochthonous) pollen in clastic sediment units hampers vegetation and climatic reconstructions during the LS and Eemian. The early appearance of Picea in zone E4 and Abies in zone E5 in clastic sediment intervals can be related to long-distance transport by the river Rhine and redistribution in the Eemian delta. Local vegetation development can complicate regional biostratigraphic correlations. Alnus, considered characteristic for the late Eemian (E5-6), shows large differences over short distances in the Amersfoort Basin, related to local alder growth since Eemian E3. Carpinus, diagnostic for pollen zone E5, shows high values in the basins adjacent to higher, well-drained ice-pushed ridges, but low values in low-relief environments. Salt- to brackish-water marshes were present during high sea level in zone E5 in the Amsterdam and Amersfoort basins, while further upstream in the Rhine delta brackish to fresh-water tidal conditions dominated. In line with Zagwijn (1961), the E6 to EWI boundary is defined at the first opening of the vegetation cover with Calluna, Poaceae and Artemisia increase, often coinciding with a lithological change from organic to clastic deposition, reflecting increased landscape instability. The cores from the Amersfoort basin reveal a complete Eemian to Early Weichselian record. It is suggested to define the boundary stratotype for the base of the Weichselian Stage in the Amersfoort Basin. The current stratotype Amsterdam-Terminal reveals a fully developed LS to Eemian transition and contains the boundary stratotype for the base of the Eemian Stage.

Evolución paleoambiental de una turbera finiholocena en el sector suroccidental del Parque Nacional de Doñana (S.O. España)

El análisis multidisciplinar de un perfil descubierto por las tormentas invernales en el litoral del Parque Nacional de Doñana ha permitido reconstruir la evolución de su sector occidental durante el Holoceno superior. Se han definido 3 fases que reflejan el paso desde una marisma de aguas salobres (FA-1) a una laguna de aguas dulces transformada en turbera (FA-2), para finalizar con el depósito de cordones dunares (FA-3).

Anthropogenic Changes in a Mediterranean Coastal Wetland during the Last Century—The Case of Gialova Lagoon, Messinia, Greece

Human interventions during the last 70 years have altered the characteristics of the Gialova Lagoon, a coastal wetland that is part of a wider Natura 2000 site. In this study, we explore how human interventions and climate altered the wetland’s hydrological conditions and habitats, leading to changing wetland functions over time. Our interpretations are based on a mixed methodological approach combining conceptual hydrologic models, analysis of aerial photographs, local knowledge, field observations, and GIS (Geographic Information System) analyses. The results show that the combined effects of human interventions and climate have led to increased salinity in the wetland over time. As a result, the fresh and brackish water marshes have gradually been turned into open water or replaced by halophytic vegetation with profound ecological implications. Furthermore, current human activities inside the Natura 2000 area and in the surrounding areas could further impact on the water quantity and quality in the wetland, and on its sensitive ecosystems. We suggest that a more holistic understanding of the broader socio-ecological system is needed to understand the dynamics of the wetland and to achieve sustainable long-term management and conservation strategies.

Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary

Estuarine tidal marshes provide favorable conditions for nitrous oxide (N2O) production. Saltwater intrusion caused by sea-level rise would exert complex effects on the production and emission of N2O in estuarine tidal marshes; however, few studies have been conducted on its effects on N2O emissions. Salinity gradients are a common occurrence in estuarine tidal marshes. Studies on production and emission of N2O in tidal marshes with different salinities may elucidate the impact of saltwater intrusion on the emission of greenhouse gases. This study explores the seasonal variations of N2O fluxes and soil denitrification rates in freshwater (Daoqingzhou wetland) and brackish (Shanyutan wetland) tidal marshes dominated by Cyperus malaccensis var. brevifolius (shichito matgrass) in the Min River estuary, southeastern China. N2O fluxes in both marshes showed strong temporal variability. The highest N2O fluxes were observed in the hot and wet summer months, whereas the lowest fluxes were observed in the cold winter and autumn months. N2O fluxes from the freshwater marsh (48.81±9.01μgm−2h−1) were significantly higher (p<0.05) than those from the brackish-water marsh (27.69±4.01μgm−2h−1). Soil denitrification rates showed a similar temporal pattern, with the highest rates observed in summer and the lowest in winter. Similarly, soil denitrification rates were significantly higher (p<0.05) in the freshwater marsh (32.72±19.15μmolNm−2h−1) than in the brackish-water marsh (4.97±2.64μmolNm−2h−1). Temperature and the salinity, sulfate (SO42−), and ammonia nitrogen (NH4+-N) concentrations of the overlying water were key factors affecting soil denitrification rates. N2O fluxes and soil denitrification rates demonstrated negative correlations with salinity and SO42− concentrations in both marshes. The results indicate that increased seawater intrusion would reduce N2O emissions from estuarine tidal wetlands and exert a negative feedback on the climate system.

Design of real-time and long-term hydrologic and water quality wetland monitoring stations in South Florida, USA

Hydrologic regimes in tropical and subtropical regions (e.g. hurricanes, tropical storms, and droughts) impact biogeochemical processes in created and restored wetlands with variability of wet/dry seasons and extreme weather events. Our South Florida Wetland Monitoring Network (SFWMN) with three real-time hydrologic, water quality, and meteorological field stations was established by the Everglades Wetland Research Park of Florida Gulf Coast University in the subtropical Southwest Florida, USA, beginning in 2012. The stations include a restored freshwater marsh (RFM) and adjacent meteorological field station; a restored brackish water marsh (RBM); and a created freshwater treatment wetland system and adjacent meterological station (CFTW). Continuous observations of water depth, temperature, salinity, and pH for the period of January 2012 to January 2016 indicate significant differences among the restored freshwater marsh, the restored brackish marsh, and the created freshwater treatment wetlands for water temperature and pH for wet and dry seasons. The brackish wetland salinity fluctuated between 26.16 (in the dry season) to 1.03ppt (in the wet season).The real-time dataset allowed up-to-date information of the frequency and duration of severe weather events illustrating, for example, that 70% of the 2012 annual rainfall (1129mm) occurring in July and August with a 75.4mm precipitation during one event—tropical storm Isaac on August 26–28, 2012. This storm led to a water stage peak in the brackish wetland due to excessive watershed runoff, not tidal surges, and salinity decreased from 22.3 to 5.5ppt.The coefficient of variation (CV) for water depth and water quality from all wetland monitoring stations exhibited similar variations during all seasons, except when the salinity for the brackish marsh (RBM) had the highest CV values (1.02) in the wet season. Principal component analysis (PCA) at each station identified the variance in water depth and water quality parameters as due to seasonal changes of precipitation in distinct wet and dry seasons. The data from these monitoring stations are also used for research by scholars and students as well as for teaching a better understanding of wetlands dynamics and function in the classroom. As a whole, these stations are being used to bring awareness about the fragile and unique hydrological conditions of wetlands in subtropical Southwest Florida, especially for long-term conditions related to sea level changes and more frequent tropical storms.

Subspecies delineation amid phenotypic, geographic and genetic discordance in a songbird.

Understanding the processes that drive divergence within and among species is a long-standing goal in evolutionary biology. Traditional approaches to assessing differentiation rely on phenotypes to identify intra- and interspecific variation, but many species express subtle morphological gradients in which boundaries among forms are unclear. This intraspecific variation may be driven by differential adaptation to local conditions and may thereby reflect the evolutionary potential within a species. Here, we combine genetic and morphological data to evaluate intraspecific variation within the Nelson's (Ammodramus nelsoni) and salt marsh (Ammodramus caudacutus) sparrow complex, a group with populations that span considerable geographic distributions and a habitat gradient. We evaluated genetic structure among and within five putative subspecies of A.nelsoni and A.caudacutus using a reduced-representation sequencing approach to generate a panel of 1929 SNPs among 69 individuals. Although we detected morphological differences among some groups, individuals sorted along a continuous phenotypic gradient. In contrast, the genetic data identified three distinct clusters corresponding to populations that inhabit coastal salt marsh, interior freshwater marsh and coastal brackish-water marsh habitats. These patterns support the current species-level recognition but do not match the subspecies-level taxonomy within each species-a finding which may have important conservation implications. We identified loci exhibiting patterns of elevated divergence among and within these species, indicating a role for local selective pressures in driving patterns of differentiation across the complex. We conclude that this evidence for adaptive variation among subspecies warrants the consideration of evolutionary potential and genetic novelty when identifying conservation units for this group.

Clamming Up: An Ethnoarchaeological Study of a Costa Rican Artisanal Clam Fishery

ABSTRACTA vibrant artisanal fishery of the brackish water marsh clam (Polymesoda acuta) is located in the lower Río Tempisque, Costa Rica. Fishermen harvest clams from shoals according to tidal and lunar cycles. They take most clams directly to riverside processing stations to be cooked and sold as salted meat, although some cooked clams are dried, and others sold live. Processing activities result in the formation of shellmounds that share significant similarities and some differences with ancient marsh clam shellmounds of coastal Chiapas, Mexico. In this study, procurement and processing activities are described and quantified, revealing the substantial amount of labor and skill involved in the modern fishery. Implications for archaeological preservation and predictions from optimal foraging theory are evaluated.

Freshwater wetlands: fertile grounds for the invasive Phragmites australis in a climate change context.

Climate change will likely affect flooding regimes, which have a large influence on the functioning of freshwater riparian wetlands. Low water levels predicted for several fluvial systems make wetlands especially vulnerable to the spread of invaders, such as the common reed (Phragmites australis), one of the most invasive species in North America. We developed a model to map the distribution of potential germination grounds of the common reed in freshwater wetlands of the St. Lawrence River (Québec, Canada) under current climate conditions and used this model to predict their future distribution under two climate change scenarios simulated for 2050. We gathered historical and recent (remote sensing) data on the distribution of common reed stands for model calibration and validation purposes, then determined the parameters controlling the species establishment by seed. A two-dimensional model and the identified parameters were used to simulate the current (2010) and future (2050) distribution of germination grounds. Common reed stands are not widespread along the St. Lawrence River (212 ha), but our model suggests that current climate conditions are already conducive to considerable further expansion (>16,000 ha). Climate change may also exacerbate the expansion, particularly if river water levels drop, which will expose large bare areas propitious to seed germination. This phenomenon may be particularly important in one sector of the river, where existing common reed stands could increase their areas by a factor of 100, potentially creating the most extensive reedbed complex in North America. After colonizing salt and brackishwater marshes, the common reed could considerably expand into the freshwater marshes of North America which cover several million hectares. The effects of common reed expansion on biodiversity are difficult to predict, but likely to be highly deleterious given the competitiveness of the invader and the biological richness of freshwater wetlands.

A Holocene sedimentary record of tectonically influenced reduced channel mobility, Skokomish River delta, Washington State, USA

At the Skokomish River delta in Washington State's Puget Lowland, coseismic uplift and tilting trapped the river against a valley wall, resulting in little to no channel migration for the last 1000years. The most recent earthquake occurred before AD 780–990, based on stratigraphic evidence such as sand blows and abrupt facies changes. Since the hypothesized tilting a 5-km-long section of the river has not migrated laterally or avulsed, resulting in reduced migration and a muddy intertidal flat that is 2km wider in the east than on the west side of Annas Bay. A ridge running perpendicular to the river may also have restricted channel mobility. The ridge may be either the surface expression of a blind thrust fault or a relict, uplifted and tilted shoreline. The uplift and tilting of the delta can be ascribed to any of three nearby active fault zones, of which the most likely, based on the orientation of deformation, is the Saddle Mountain fault zone, which produced a surface rupture 1000–1300years ago. The delta has experienced submergence since the earthquake. A forest that colonized an uplifted part of the delta about 800–1200years ago was later submerged by at least 1.6m and is now a brackish-water marsh.

Effects of low salinity media on growth, condition, and gill ion transporter expression in juvenile Gulf killifish, Fundulus grandis

The Gulf killifish, Fundulus grandis, is a euryhaline teleost which has important ecological roles in the brackish-water marshes of its native range as well as commercial value as live bait for saltwater anglers. Effects of osmoregulation on growth, survival, and body condition at 0.5, 5.0, 8.0 and 12.0‰ salinity were studied in F. grandis juveniles during a 12-week trial. Relative expression of genes encoding the ion transport proteins Na+/K+-ATPase (NKA), Na+/K+/2Cl− cotransporter(NKCC1), and cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel was analyzed. At 0.5‰, F. grandis showed depressed growth, body condition, and survival relative to higher salinities. NKA relative expression was elevated at 7days post-transfer but decreased at later time points in fish held at 0.5‰ while other salinities produced no such increase. NKCC1, the isoform associated with expulsion of ions in saltwater, was downregulated from week 1 to week 3 at 0.5‰ while CFTR relative expression produced no significant results across time or salinity. Our results suggest that Gulf killifish have physiological difficulties with osmoregulation at a salinity of 0.5‰ and that this leads to reduced growth performance and survival while salinities in the 5.0–12.0‰ are adequate for normal function.

Empirical tools for simulating salinity in the estuaries in Everglades National Park, Florida

Salinity in a shallow estuary is affected by upland freshwater inputs (surface runoff, stream/canal flows, groundwater), atmospheric processes (precipitation, evaporation), marine connectivity, and wind patterns. In Everglades National Park (ENP) in South Florida, the unique Everglades ecosystem exists as an interconnected system of fresh, brackish, and salt water marshes, mangroves, and open water. For this effort a coastal aquifer conceptual model of the Everglades hydrologic system was used with traditional correlation and regression hydrologic techniques to create a series of multiple linear regression (MLR) salinity models from observed hydrologic, marine, and weather data. The 37 ENP MLR salinity models cover most of the estuarine areas of ENP and produce daily salinity simulations that are capable of estimating 65–80% of the daily variability in salinity depending upon the model. The Root Mean Squared Error is typically about 2–4 salinity units, and there is little bias in the predictions. However, the absolute error of a model prediction in the nearshore embayments and the mangrove zone of Florida Bay may be relatively large for a particular daily simulation during the seasonal transitions. Comparisons show that the models group regionally by similar independent variables and salinity regimes. The MLR salinity models have approximately the same expected range of simulation accuracy and error as higher spatial resolution salinity models.

The sediments of the ‘Stagno di Maccarese’ marsh (Tiber river delta, central Italy): A late-Holocene record of natural and human-induced environmental changes

The environmental evolution, inferred from the sedimentary sequence, that has occurred during the last three millennia in a drained coastal marsh in the Tiber delta is presented. The stratigraphy of the sediments has been revealed through excavation of 7 km of trenches in an area of about 1.5 km2. The most evident environmental variations are represented by the transformation of freshwater marshes into brackish-water marshes, around the ninth–eighth centuries bc, and from brackish-water to freshwater marshes during the fourteenth–fifteenth centuries ad. The change in the water salinity was produced by the opening and closure of an inlet connecting the marshes and the sea because of the evolution of the delta. Other environmental variations are reflected in the fluctuations in the water level of brackish marshes: in a general trend towards an increase in water level, probably caused by the late-Holocene sea level increase, some phases of water decrease in the range of 10–20 cm occurred. The majority of the environmental changes were largely produced by erosion and sedimentary events connected with Tiber delta variations induced both by human impact and climate. The lower water levels were contemporary with glacial advances in the Alps and the Apennine chains. At least one of the five decreases of the water level was contemporaneous with a marine regression documented in Italy.

Regeneration of coastal marsh vegetation impacted by hurricanes Katrina and Rita

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

English

The influence aeration and light intensity could have on biomass production and protein biosynthesis in a&nbsp;Spirulina&nbsp;sp. isolated from an oil-polluted brackish water marsh is examined.&nbsp; Biomass, proximal composition and amino acid composition obtained from aerated cultures of the organism were compared with non-aerated cultures after a 35 days incubation period. Cultures of the organism were also grown in ordinary sunlight, and artificial light intensities of ca.7.5 and 15&nbsp;mEm-2S-1. Results showed that both aeration and exposing the cultures of the organism to artificial illumination improved biomass production and protein biosynthesis in the&nbsp;Spirulina&nbsp;sp. compared to sunlight illuminated and non aerated cultures. These results would be useful in optimizing growth conditions for maximum biomass and protein yields from the organism. &nbsp; Key words:&nbsp;Spirulina,&nbsp;aeration, light intensity, biomass, protein.

Rehabilitation of habitat connectivity between two important marsh areas divided by a major road with heavy traffic

‘Vignarca’ is a major road between Piombino and Follonica along the coast in Southern Tuscany, in the Province of Livorno. Until the 1940s, the area crossed by Vignarca was a large marsh, which in turn was the remains of an ancient costal lake (Lake Piombino). Over the years the area was reclaimed, and now only two wetlands remain: one is a typical brackish water marsh (‘orti’) and the other a freshwater marsh (‘Bottagone’) with large areas of reedbeds. These marshes are bisected by the Vignarca road. Since 1991, the marshes have been protected by the WWF by the establishment of the orti-Bottagone Nature Reserve.

Behavior of the Grass Shrimp Palaemonetes pugio and its Response to the Presence of the Predatory Fish Fundulus heteroclitus

The grass shrimp Palaemonetes pugio, a common inhabitant of brackish water marshes, is often used in experimental studies. To support studies concerned with the behavior of P. pugio in controlled laboratory conditions, a behavior catalog (or ethogram) was developed. Twelve grass shrimp activities, six moving and six stationary, were observed and described. The most frequently observed activities included hovering in the water column, walking and three types of swimming. Activities observed less often included backward thrusting, jabbing with the rostrum tip and taking cover. The value of the ethogram was assessed using a predator-prey experiment in which the frequency of grass shrimp behaviors in response the predatory fish Fundulus heteroclitus was examined. In the presence of a fish, grass shrimp decreased the frequency of swimming and increased the frequency of covered and motionless behaviors. We also noted a significant increase in the occurrence of two active antipredator defenses: backward thrust and jabbing with the rostrum tip. Backward thrust quickly propelled shrimp away from a fish. Jabbing with the rostrum tip was directed toward an advancing fish and usually caused the fish to swim off in the opposite direction. These observations provide clues as to the levels and types of interactions that occur between the grass shrimp and their fish predators in the wild. The catalog of recorded activities may be of value in future studies designed to examine the effect of different experimental conditions on grass shrimp behavior.

Comparison of nutrient and contaminant fluxes in two areas with different hydrological regimes (Empordà Wetlands, NE Spain)

Nutrient (N and P), heavy metal (Ni, Cd, Cr, Cu and Pb) and pesticide (DDT, DDD, DDE, lindane, aldrin, endrin, dieldrin, permethrin, atrazine and simazine) concentrations in water and sediment were analysed in the Empordà Wetlands, a Mediterranean wetland area in NE Spain. Mean nutrient and contaminant concentrations and input and output loads via tributaries were compared in two marshes with different water turnover: a freshwater marsh (FWM), with a high water turnover rate due to continuous surface water inputs and outputs, and a brackish water marsh (BWM), with lower turnover and no continuous surface output, where water remains confined during dry periods. Mean concentrations of most heavy metals exceeded the maximum permissible concentration (MPC) in BWM, whilst only some pesticides reached MPC in FWM. The confined waters of BWM showed higher sensitivity to contaminant input loadings than FWM due to the lack of continuous water outputs. Non-point source pollution inputs during runoff (mainly in FWM) and concentration during confinement (mainly in BWM) showed as the main environmental problems related to nutrients and contaminants in these ecosystems. Thus, the importance of confinement and its effect on pollutant concentrations must be borne in mind to achieve correct management of Mediterranean wetlands.