Seagrass is a key stone component for the Indian River Lagoon (IRL) ecosystem, and therefore it is an important topic for many studies in the lagoon. This study focuses on the effects of seagrass beds on the hydrodynamics in the IRL. A hydrodynamic model based on the Delft3D modeling system has been developed for the southern IRL including the St. Lucie estuary, Ft. Pierce and St. Lucie Inlets, and adjacent coastal waters. The model is driven by freshwater inputs from the watershed, tides, meteorological forcing, and oceanic boundary forcing. The model has been systematically calibrated through a series of numerical experiments for key parameters, particularly the bottom roughness, and configuration including heat flux formulation and bottom bathymetry. The model skills were evaluated with quantitative metrics (point-to-point correlation, root-mean-square difference, and mean bias) to gauge the agreements between model and data for key variables including temperature, salinity, and currents. A three-year (2013-2015) simulation has been performed, and the results have been validated with available data including observations at HBOI Land-Ocean Biogeochemistry Observatory (LOBO) stations and in situ measurements from various sources. The validated model is then used to investigate the effects of 1) model vertical resolution (total number of model vertical layers), 2) spatial variability of surface winds, and 3) seagrass beds on the simulated hydrodynamics. The study focuses on the vicinity of Ft. Pierce Inlet, where significant seagrass coverage can be found. A series of numerical experiments were performed with a combination of different configurations. Overall, the experiment with 2-dimensional (2-D) winds, ten vertical layers and incorporating seagrass provided the most satisfactory outcomes. Overall, both vertical resolution and spatial variability of surface winds affect significantly the model results. In particular, increasing vertical resolution improves model prediction of temperature, salinity and currents. Similarly, the model with 2-D winds yields more realistic results than the model forced by 0-D winds. The seagrass beds have significant effects on the model results, particularly the tidal and sub-tidal currents. In general, model results show that both tidal and sub-tidal currents are much weaker due to increase bottom friction from seagrass. For tidal currents, the strongest impacts lie in the main channel (inter-coastal waterway) and western part of the lagoon, where strong tidal currents can be found. Inclusion of seagrass in the model also improves the simulation of sub-tidal currents. Seagrass beds also affect model temperature and salinity including strengthening vertical stratification. In general, seagrass effects vary over time, particularly tidal cycle with stronger effects seen in flood and ebb tides, and seasonal cycle with stronger effects in the summer than in winter. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S.) -- Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.

1. For the first time detailed phytosociological measurements, using objective methods have been made in a large number of lowland successional stands throughout eastern Canada. 2. Soil and soil surface organic matter samples were collected on a volume-weight basis for all stands studied. An increased use of bulk-density sampling methods is advocated as they allow the conversion of all nutrient percentage and parts per million analyses to actual weights par unit area profile depth, as was done in the present work. [...]

The aim of this study was to describe the plant communities within the eastern portion of the Mkuze Wetland, including only those systems that have a substantial input of water from the Mbazwane Stream, and to determine environmental factors that control distribution. The Mbazwane Wetland has a catchment of reworked sandy marine sediments, and its gradient is very shallow, such that water moving downstream through this system is free of suspended sediment and is clear. In addition, it has low conductivity suggesting a low solute load. A total of nine communities were identified in the study, based on the TWINSPAN cluster analysis. These are: Ficus trichopodalScleria angusta Swamp Forest Community; Rubus rigidus Disturbed Swamp Forest; Phragmites australis/Ficus trichopoda Precursor Swamp Forest; Typha capenis/Pycreus mundii/Leersia hexandra Marsh Community; Phragmites australis/Cladium mariscus/Ficus verruculosa Swamp Community; Cyperus papyrus Swamp Community; Echinochloa pyramidalis Floodplain Community; Ischaemum fasciculatum/Centella asiatica Floodplain Community; Paspalum distichum Floodplain Community. These communities can be divided into three broad groups, swamp forest, emergent herbaceous swamp/marsh and grassland floodplain communities. One of the main environmental variables influencing distribution was duration and depth of flooding, which separated the permanently flooded swamp and emergent swamp/marsh communities from the seasonally/ periodically inundated floodplain communities. Environmental variables that account for further division of the communities within these two groups, appear to be disturbances from fire and substratum differences related to sediment deposition from the Mkuze River, which enters the lower Mbazwane Wetland from the west. The permanently flooded swamp forest communities, are largely restricted to the northern parts of the study area, while the emergent swamp/ marsh communities, are restricted to the southern part of the study area. The swamp forest community is fringed to the west by an extremely high and steep dune, while the swamp/marsh communities are fringed to the west by much lower and more gently sloping dunes. It is suggested here that wildfires in conjunction with topography influence the distribution of these two groups of communities. An analysis of diurnal variation in temperature in the winter months (June - August) for winds (greater than l.0m/s) reveals that winds blowing from the west to north-west are associated with extremely high temperatures that persist during the day and well into the night. These are berg wind conditions that have been strongly linked to the desiccation of vegetation and promoting its susceptibility to burning in wildfires, and it is during these conditions that fires are most likely to occur in the study area. Swamp forest is situated in areas that are protected from direct exposure to these winds by the high, steep dune immediately to the west. These are thus likely to be naturally protected from fire. In contrast the herbaceous swamp/marsh communities are not protected from wind or fire by a similar topographic feature. Mature swamp forests were restricted to these 'berg wind shadow' areas, where there is complete protection from fire. Precursor and disturbed swamp forests occur where they are less protected and thus are infrequently exposed to fire. The distribution of the permanently flooded swamp/marsh communities in the areas exposed to fire appears to be related to the input of nutrients. The Cyperus papyrus Swamp Community was rooted in clay rich peat in the area around the Mkuze Delta that receives an input of clay from the Mkuze River during very high floods. In contrast, the Phragmites australis/Cladium mariscuslLeersia hexandra Swamp Community was rooted in peat with low ash content, as there is little or no input of clay from the Mkuze River, even during high floods. The seasonally/periodically- flooded communities included the Echinochloa pyramidalis Floodplain Community, the Ischaemum fasciculatum/Centella asiatica Floodplain Community and the Paspalum distichum Floodplain Community. The Echinochloa pyramidalis Floodplain Community was restricted to seasonally flooded areas receiving an input of clastic sediment from the Mkuze River during high floods, while the other floodplain communities occurred in areas receiving water from the relatively sediment free Mbazwane Stream. The distribution of these two communities appears to be influenced by the duration of inundation, with the lschaemum fasciculatum/Centella asiatica Floodplain Community being at higher elevation and therefore less frequently flooded than the Paspalum distichum Floodplain Community. / Thesis (M.Sc.)-University of Natal, Durban, 2000.

This study examines the relative contribution of algae and vascular plant litter to the food chains of freshwater marshes. Twelve enclosures (5 m diam.) were deployed in a nutrient-poor marsh of the Interlake region of Manitoba. Algae levels in six of the enclosures were increased by fertilizing the water column. In addition, the hardstem bulrush (Scirpus lacustris glaucus (Sm.) Hartm) litter present was replaced with a non-nutritive artificial substrate in half of the fertilized and unfertilized enclosures. Fertilization did not affect the dry weight loss of bulrush litter, but N and P concentrations were higher in the decomposing litter of the fertilized treatments. Dominant taxa of nektonic herbivores-detritivores responded to fertilization but were not affected by the replacement of plant litter by a non-nutritive substrate. Epiphytic herbivores-detritivores responded to changes in both detritus and algal food sources. Fertilization resulted in early peaks of emergence for the Chironominae, Tanypodinae and Orthocladiinae. Emergence data late in the study period suggest that the importance of litter as a food source may increase as decomposition progresses.

Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 153-166).

This curriculum guide is for grades four through six. It examines how wetlands, wildlife, and people interact and depend upon each other. The San Jacinto Valley wetland area is used as an example of wetland habitat destruction from population pressures that have changed the natural landscape. It is also used as an example of what habitat reconstruction can do to restore vital habitats. Through student contact with the wetlands increased awareness of the fragile interrelationships between the physical and biological components of a wetland habitat is gained. Students can use ecological themes to help them assimilate collected and given data into logical cohesive ideas, laying the ground work for developing an environmental action project.

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