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Ecology of the seagrasses of south Florida: a community profile

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Abstract

A detailed description is given of the community structure and ecosystem processes of the seagrass ecosystems of south Florida. This description is based upon a compilation of information from numerous published and unpublished sources. The material covered includes distribution, systematics, physiology, and growth of the plants, as well as succession and community development. The role of seagrass ecosystems in providing both food and shelter for juveniles as well as foraging grounds for larger organisms is treated in detail. Emphasis is given to the functional role of seagrass communities in the overall coastal marine system. The final section considers the impacts of human development on seagrass ecosystems and their value to both man and the natural system. Because seagrass systems are fully submerged and less visually obvious, recognition of their value as a natural resource has been slower than that of the emergent coastal communities. They must, however, be treated as a valuable natural resource and preserved from further degradation.

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... Due to its wide range, H. zosterae is perceived to be an abundant species, though most survey data do not support this assumption. Zieman (1982) describes H. zosterae as "abundant in seagrass throughout south Florida," but this generalization is contradicted by the survey data reported in the same study. Based on surveys reporting abundance as either rare, present, common, or abundant, H. zosterae is not reported as abundant in any survey (Zieman 1982). ...
... Zieman (1982) describes H. zosterae as "abundant in seagrass throughout south Florida," but this generalization is contradicted by the survey data reported in the same study. Based on surveys reporting abundance as either rare, present, common, or abundant, H. zosterae is not reported as abundant in any survey (Zieman 1982). It is reported as common in South Biscayne Bay (Bader and Poessler 1971), as present in Porpoise Lake (Hudson et al. 1970), and as rare in all other surveyed areas including North Biscayne Bay, Card Sound, Metecumbe Key, Whitewater Bay, Fakahatchee Bay, Marco Island, and Rookery Bay (Zieman 1982, p. 124 (Sheridan et al. 1997, Matheson et al. 1999. ...
... The dwarf seahorse is a habitat specialist that is completely dependent on healthy seagrass beds for survival, and the spill and its aftermath pose substantial risk to seagrass meadows in the Gulf (Whigham et al. 2010, p. 1). Oil pollution has severe impacts on seagrasses which can persist for decades (Zieman 1982, p. 87, FDEP 2009b). Impacts of oil and dispersants on seagrass range from complete mortality to sublethal stress and chronic impairment of seagrass metabolism and function (Hatcher and Larkum 1982, Thorhaug and Marcus 1987, Jackson et al. 1989, Ralph and Burchett 1998, Sandulli 1998, Peirano et al. 2005, Scarlett et al. 2005. ...
... A decline in the amount of seagrass habitat/coverage has occurred in Estero Bay and Rookery Bay, with an almost complete disappearance in Naples Bay. The result of this decline is a reduction in potential habitat for a number of seagrass dependent species, and especially the juvenile life stages of many estuarine dependent species (Virnstein1987, Stoner 1984, Zieman 1982. Specifically, larval gag grouper (Mycteroperca microlepis) use sea grass beds as settlement substrate after having hatched offshore on natural hard bottom structures. ...
... The grass beds provide protection from predation for animals living in it. The dense seagrass blades and rhizomes associated with the grasses provide cover for invertebrates and small fishes while also interfering with the feeding efficiency of their potential predators (Zieman 1982). Reduction in size and health of SAV beds effects the location, abundance, and speciation of fisheries in the coastal bays. ...
... Each species of SAV has their own temperature and salinity tolerance ranges and their tolerance to salinity variation is similar to their temperature tolerances. Halodule wrightii is the most broadly euryhaline, Thallassia testudium is intermediate, and Syringodium filiforme and Halophila have the narrowest tolerance ranges (McMillian 1979, Zieman 1982. Vallisneria americana is generally a freshwater grass but can tolerate salinities of near 10 ppt. ...
Technical Report
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This report summarizes impacts of altered hydrology and degraded water quality on coastal bays located on the southwest coast of Florida including Estero Bay, Naples Bay, Rookery Bay. The report was prepared for the Southwest Florida Feasibility Study that was a component of the Comprehensive Everglades Restoration Plan.
... The second most significant threat to manatees is the loss and degradation of habitat, due primarily to direct damage by aquatic recreational and commercial boating activities, coastal construction, and pollution from sewage discharge and storm water runoff (MMC 1992, Smith 1993. The seagrass beds that manatees rely on for foraging, mating, calving incur direct damage from boat propellers (Zieman 1982). Propeller dredging of bottom habitat by boats, propeller wash, and wave wake disturbance cause boat induced turbidity. ...
... Manatees are opportunistic herbivores and feed on a variety of submergent, emergent, and floating vegetation with seagrasses comprising the largest component of their diet in south Florida (Hartman 1979, Zieman 1982, Smith 1993. Manatees usually forage in shallow grass beds that are adjacent to deeper channels (Hartman 1979, Powell andRathbun 1984). ...
... The grass beds provide protection from predation for animals living in it. The dense seagrass blades and rhizomes associated with the grasses provide cover for invertebrates and small fishes while also interfering with the feeding efficiency of their potential predators (Zieman 1982). Reduction in size and health of SAV beds effects the location, abundance, and speciation of fisheries in the estuary. ...
Technical Report
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Report for the Southwest Florida Feasibility Study.
... The second most significant threat to manatees is the loss and degradation of habitat, due primarily to direct damage by aquatic recreational and commercial boating activities, coastal construction, and pollution from sewage discharge and storm water runoff (MMC 1992, Smith 1993). The seagrass beds that manatees rely on for foraging, mating, calving incur direct damage from boat propellers (Zieman 1982). Propeller dredging of bottom habitat by boats, propeller wash, and wave wake disturbance cause boat induced turbidity. ...
... Manatees are opportunistic herbivores and feed on a variety of submergent, emergent, and floating vegetation with seagrasses comprising the largest component of their diet in south Florida (Hartman 1979, Zieman 1982, Smith 1993. Manatees usually forage in shallow grass beds that are adjacent to deeper channels (Hartman 1979, Powell andRathbun 1984). ...
... The grass beds provide protection from predation for animals living in it. The dense seagrass blades and rhizomes associated with the grasses provide cover for invertebrates and small fishes while also interfering with the feeding efficiency of their potential predators (Zieman 1982). Reduction in size and health of SAV beds effects the location, abundance, and speciation of fisheries in the estuary. ...
... All three experiments were conducted in the Lignumvitae Key Submerged Land Management Area (LKSLMA) in the middle Florida Keys (24.91°N, 80.68°W) (Fig. 1). LKSLMA is comprised of extensive, shallow, calcium carbonate-based seagrass banks dominated by T. testudinum typical of south Florida, the tropical western Atlantic and the Caribbean region (Zieman, 1982;Short et al., 1985). Water depths were generally ≤1.5 m (mean high water) and the tidal range was approximately 1m. ...
... We tested the application of compressed succession in combination with topographic restoration in propeller scars in Experiment 2 and a much larger excavation in Experiment 3. Normally, undisturbed T. testudinum meadows trap and stabilize fine-grained sediments and organic matter which provide unconsolidated substrate and nutrients required for the development and maintenance of a seagrass meadow (Zieman, 1982;Williams, 1990). This important physical-chemical process occurs very slowly in naturally developing T. testudinum beds (Zieman, 1982), and even more slowly in meadows recovering from severe physical disturbance by vessel excavations Di Carlo and Kenworthy, 2008;Uhrin et al., 2011;Bourque and Fourqurean, 2014;Bourque et al., 2015). ...
... We tested the application of compressed succession in combination with topographic restoration in propeller scars in Experiment 2 and a much larger excavation in Experiment 3. Normally, undisturbed T. testudinum meadows trap and stabilize fine-grained sediments and organic matter which provide unconsolidated substrate and nutrients required for the development and maintenance of a seagrass meadow (Zieman, 1982;Williams, 1990). This important physical-chemical process occurs very slowly in naturally developing T. testudinum beds (Zieman, 1982), and even more slowly in meadows recovering from severe physical disturbance by vessel excavations Di Carlo and Kenworthy, 2008;Uhrin et al., 2011;Bourque and Fourqurean, 2014;Bourque et al., 2015). The natural process of filling and regrading may be delayed for years or even decades, leaving the vessel injures exposed to further degradation from scouring and expansion (Williams, 1988;Whitfield et al., 2002Whitfield et al., , 2004Di Carlo and Kenworthy, 2008;Uhrin et al., 2011). ...
Article
Shallow water seagrass meadows are frequently damaged by recreational and commercial vessels. Severe injury occurs where propeller scarring, hull groundings and mooring anchors uproot entire plants, excavate sediments, and modify the biophysical properties of the substrate. In climax tropical seagrass communities dominated by Thalassia testudinum (turtlegrass), natural recovery in these disturbances can take several years to decades, and in some environmental conditions may not occur at all. During the recovery period, important ecological services provided by seagrasses are absent or substantially diminished and injured meadows can degrade further in response to natural disturbances, e.g. strong currents and severe storms. To determine if we could accelerate rehabilitation and prevent further degradation of injured turtlegrass meadows, we evaluated a restoration method called “modified compressed succession” using the fast-growing, opportunistic species Halodule wrightii to temporarily substitute ecological services for the slower-growing, climax species T. testudinum. In three experiments we showed statistically significant increases in density and coverage rates of H. wrightii transplants fertilized by wild bird feces as compared to unfertilized treatments. In one experiment, we further demonstrated that regrading excavated injuries with sediment-filled biodegradable tubes in combination with wild bird fertilization and H. wrightii transplants also accelerated seagrass recovery. Specific recommendations are presented for the best practical application of this restoration method in the calcium carbonate-based sediments of south Florida and the wider Caribbean region.
... Como ecosistema, las praderas de pastos marinos cumplen un sinnúmero de funciones ecológicas entre las que se destacan la producción de fuentes directas e indirectas de alimento, el suministro de sustrato para la fijación de epífitos y su contribución en la recirculación de nutrientes y estabilización de sedimentos (Zieman, 1975;Young y Young, 1982;Dawes, 1986), alta producción primaria y secundaria comparable con ecosistemas terrestres aportando grandes cantidades de detrito al ecosistema (Zieman, 1982). Además actúan como refugio y sala cuna de vertebrados e invertebrados de importancia ecológica y comercial. ...
... Gracias al efecto pronunciado de la surgencia y los vientos alisios, las condiciones ambientales en La Guajira en esta época climática son muy particulares en cuanto a la temperatura, salinidad y disponibilidad de nutrientes; la salinidad con valores entre 39,00 y 43,00, sobrepasa los límites óptimos reportados en la literatura; y a pesar de que la temperatura presenta ámbitos de variación pequeños (26,00-27,50 °C), está dentro de los limites establecidos, 20,00 30,00 (Zieman, 1982). Es importante resaltar que las mediciones fueron superficiales; dado que las aguas de La Guajira presentan salinidad y temperatura superficial alta, es posible que los valores a nivel del sustrato ejerzan influencias no medidas (Angel, 1998 El ancho y la longitud foliar son considerados indicadores para el monitoreo de las condiciones ecológicas de los pastos marinos (Anón, 1990), puesto que al disminuir las dimensiones foliares se observa una respuesta ecofenotípica de T. testudinum debido a tensores naturales o antropogénicos (Durako, 1992). ...
... Como ecosistema, las praderas de pastos marinos cumplen un sinnúmero de funciones ecológicas entre las que se destacan la producción de fuentes directas e indirectas de alimento, el suministro de sustrato para la fijación de epífitos y su contribución en la recirculación de nutrientes y estabilización de sedimentos (Zieman, 1975;Young y Young, 1982;Dawes, 1986), alta producción primaria y secundaria comparable con ecosistemas terrestres aportando grandes cantidades de detrito al ecosistema (Zieman, 1982). Además actúan como refugio y sala cuna de vertebrados e invertebrados de importancia ecológica y comercial. ...
... Gracias al efecto pronunciado de la surgencia y los vientos alisios, las condiciones ambientales en La Guajira en esta época climática son muy particulares en cuanto a la temperatura, salinidad y disponibilidad de nutrientes; la salinidad con valores entre 39,00 y 43,00, sobrepasa los límites óptimos reportados en la literatura; y a pesar de que la temperatura presenta ámbitos de variación pequeños (26,00-27,50 °C), está dentro de los limites establecidos, 20,00 30,00 (Zieman, 1982). Es importante resaltar que las mediciones fueron superficiales; dado que las aguas de La Guajira presentan salinidad y temperatura superficial alta, es posible que los valores a nivel del sustrato ejerzan influencias no medidas (Angel, 1998 El ancho y la longitud foliar son considerados indicadores para el monitoreo de las condiciones ecológicas de los pastos marinos (Anón, 1990), puesto que al disminuir las dimensiones foliares se observa una respuesta ecofenotípica de T. testudinum debido a tensores naturales o antropogénicos (Durako, 1992). ...
... Gracias a estas funciones, los lechos de pastos marinos soportan una diversa comunidad de fauna, donde muchas especies de invertebrados y vertebrados de importancia comercial y ecológica encuentran además de alimento, sitios de crianza y protección (McNeill y Bell, 1992). Además, los pastos en sí son altamente productivos y aportan grandes cantidades de detrito al ecosistema (Zieman, 1982). A nivel del Caribe, constituyen uno de los ecosistemas más característicos e importantes de las zonas costeras. ...
... Algunas diferencias espaciales en las variables bióticas cuantificadas son resaltadas a continuación. Zieman (1982) y Robbins y Bell (2000) indican por ejemplo que el desarrollo óptimo de T. testudinum se da entre 0.6 y 1 m de profundidad, lo cual contrasta con la pradera estudiada, ya que ésta no presentó su mejor desarrollo a 1 m de profundidad sino a 1.5 m, evidenciado ello con mayores valores para las siguientes variables: cobertura de T. testudinum, longitud promedio de las hojas, área foliar, número de hojas por vástago, densidad, biomasa y productividad primaria. Entre las causas que podrían explican el menor desarrollo en la parte somera (< 1 m) se encuentran: el vertimiento de aguas residuales que conlleva al cubrimiento del 30% de la pradera con cianobacterias (ej. ...
... Given species-specific salinity tolerances (Zieman, 1982;Fourqurean et al., 2003;Greenawalt-Boswell et al., 2006), the distribution of seagrasses in Estero Bay was consistent with the freshwater inflow and resulting salinity patterns. Rocky Bay to the north and Big ...
... Turtle grass has an intermediate tolerance to salinity variation and occurred in the central region of Estero Bay, whereas manatee grass has a narrower tolerance and its distribution was more restricted to shoals adjacent to channels from the central passes. Halophila species (paddle grass and star grass) have been identified as being more stenohaline than manatee grass (Zieman, 1982); although some have suggested Halophila species may in fact be euryhaline (Phillips and Meñez, 1988; and references therein). Paddle and star grass were typically collected in deeper waters of the central Estero Bay, but they also occurred in the more brackish waters of the northern embayment. ...
Technical Report
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The objectives of the current study were (1) to perform comprehensive mapping of benthic habitat distributions in Estero Bay, (2) to analyze benthic habitat compositions relative to the entry points of the bay’s major tributaries, (3) to analyze aggregations of decapod crustacean inhabiting oyster reefs relative to salinity patterns in each tributary, (4) to analyze the morphometrics of turtle grass in the bay as indicators of water quality, and (5) to visually survey the estuarine system for listed species of marine reptiles during sampling efforts.
... Los pastos marinos tienen valor tanto como productor primario que aporta oxígeno y alimento a la trama tró- (Zieman, 1982;Peterson y Lubchenco, 1997;Constanza, 1997). ...
... De acuerdo con Doering y Chamberlain (1998), el decremento en salinidad y penetración de luz fueron los causantes de la disminución en las praderas de pastos en la región. Considerando trabajos anteriores (Philips, 1960;McMillan y Moseley, 1967;McMillan, 1974;Zimmerman y Livingston, 1976;Zieman, 1982;Zieman y Zieman, 1989;Adair et al., 1994;citados por Doering y Chamberlain, 1998), el rango óptimo de salinidad para el óptimo En ocasiones, la disminución en la abundancia y distribución de las comunidades de pastos marinos están en relación directa con el decremento en la cantidad de luz ocasionada recibida en las hojas por el incremento súbito de fitoplancton, epífitas y macroalgas (Kemp et al., 1988). Dixon (1998) reporta cómo la disminución de luz en la bahía de Tampa en la Florida provocó la pérdida de entre el 46 al 72 por ciento de la cobertura de pastos en un periodo de 50 años (1941 a 1991). ...
... In terms of species succession over time, the single-species beds of Thalassia testudinum represent the climax stage of the ecosystem, whereas the presence of Syringodium filiforme signals instability in the ecosystem (Zieman, 1982;Bouchon et al., 2003, Figure 11, p. 30). As long as the climax has not been reached, there is continuous competition between T. testudinum and S. filiforme that can result in heterogeneity (both spatial and temporal) within the bed, e.g. a bed may, at a given point in time, be composed of single-species zones and mixed zones, and a given zone may shift in the space of just a few months from single-species to mixed (or vice versa). ...
... One of the main differences in the functioning of seagrass-bed ecosystems between Mayotte and the Caribbean lies in the levels of Zieman (1982 herbivory. Whereas in the Indian Ocean, the level is high and the pressure is exerted primarily by green sea turtles Chelonia mydas (Figure 13), in the Caribbean, the level is relatively low and due essentially to sea urchins, given that the large herbivores were decimated over the previous centuries (Jackson et al., 2001). ...
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In the year 2000, the European water framework directive (WFD) profoundly modified water-management policies by placing ecological considerations at the heart of the decision-making process. Since then, the development of bioassessment tools to inform on the ecological status of littoral and continental surface waters has been a major objective for the European scientific community. In continental France, an array of tools are already operational. In the overseas territories (OST, the Départements d’outremer in French), a number of tools have been validated and legally approved for rivers. For the coastal waters of the island OSTs (Guadeloupe, Martinique, Mayotte and Réunion Island), the idea was to develop similar methods for coral reefs and beds of phanerogams (seagrass) that often lie just off the coasts of tropical islands. Major issues are involved in the conservation and protection of these emblematic ecosystems that serve as the basis for many economic and social activities. But in terms of the specific WFD needs, can coral reefs and seagrasses serve as indicators suited to assessing the ecological status of water bodies? The development of such tools represents a scientific challenge given the paucity of available knowledge on the ecology and functioning of these tropical ecosystems, and the relative lack of experience in their assessment. The Seagrass and reef benthos national work group was set up in 2011 to collectively provide science advice on the topic. This document sums up the discussions and work of the group from 2011 to 2014, during three symposia and two missions in the field. Following a presentation of the context (Chapter 1), the discussion turns to the main topics addressed, namely an evaluation of the relevance of seagrasses and reef benthos in terms of WFD monitoring and assessment of water bodies (Chapter 2), identification of the parameters best suited to informing on the ecological status of coastal water bodies (Chapter 3), the protocols required to acquire the data (Chapter 4) and, finally, the work required to define the quality criteria (Chapter 5).
... Thalassia testudinum Banks ex König (turtle grass) is the dominant seagrass species in the subtropical/tropical Atlantic and Caribbean region (den Hartog, 1970;Green and Short, 2003). This species has high light requirements and is considered to be the climax species in marine seagrass systems (Zieman, 1982). T. testudinum is also the dominant seagrass and dominant physical structure in Florida Bay, a shallow (<2 m, Schomer and Drew, 1982) subtropical estuary that exhibits wide variations in salinity and water clarity (Zieman, 1982;Hall et al., 1999;Durako et al., 2002). ...
... This species has high light requirements and is considered to be the climax species in marine seagrass systems (Zieman, 1982). T. testudinum is also the dominant seagrass and dominant physical structure in Florida Bay, a shallow (<2 m, Schomer and Drew, 1982) subtropical estuary that exhibits wide variations in salinity and water clarity (Zieman, 1982;Hall et al., 1999;Durako et al., 2002). Two massive die-offs of T. testudinum have occurred in Florida Bay, United States, the first in 1987-1990(Robblee et al., 1991 and more recently in late summer 2015 (Hall et al., 2016). ...
Article
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Thalassia testudinum (turtle grass) is the dominant and climax-successional seagrass species in the subtropical/tropical Atlantic and Caribbean region. Two die-offs of T. testudinum in Florida Bay, United States have raised concerns regarding the resilience of this species to environmental disturbances. Seedlings are important in recovery of T. testudinum, following disturbance events. Leaf spectral reflectance [R(λ)] was measured in T. testudinum seedlings exposed for 2 weeks to three salinities (20, 35, and 50) and two light levels (full sun and 50–70% light reduction) in experimental mesocosms. Multivariate analyses indicated that hypersalinity had a greater effect on spectral reflectance than hyposalinity or light reduction. There was an increase in variability and flattening of reflectance spectra at the highest salinity. All three salinity treatments had distinct reflectance spectra across green wavelengths (530–580 nm), with additional discrimination between 20 versus 50 and 35 versus 50 treatments across red wavelengths (630–690 nm). Red:Green reflectance ratios were highest and photochemical reflective index values were lowest for the salinity 50 treatment, but were not significantly different between the salinity 20 and 35 treatments. The changes in the R(λ) spectra for the salinity 50 seedlings were consistent with previously observed reductions in leaf pigments and maximum photochemical efficiency of photosystem II. These observations indicate that leaf spectral reflectance is a sensitive indicator of plant stress in T. testudinum seedlings and that seedlings are more sensitive to short-term exposures to hypersalinity than hyposalinity.
... Roots also branch off of the rhizomes and absorb nutrients and help anchor the plants in the substrate (Thayer et al. 1984;Larkham et al. 1989). This complex rhizome and root structure also provides an elaborate habitat for infaunal invertebrates (Zieman 1982;Thayer et al. 1984). Some animals consume SAV directly, including manatees, sea turtles, crustaceans and some waterfowl species. ...
... SAV beds form one of the most productive plant communities in the world. They function as spawning and nursery habitats for numerous fish and invertebrates species, and also provide feeding grounds for both resident and transient fish, invertebrate, mammal, and bird species (Zieman 1982;Thayer et al. 1984;Orth et al. 1984;Day et al. 1989;Heck et al. 1989;Mattila et al. 1999). In addition to their productivity, SAV species are important ecosystem engineers, trapping and stabilizing sediments, provide wave attenuation, and nutrient cycling benefits (NCDEQ 2016). ...
Technical Report
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This white paper provides a means of evaluating potential impacts of offshore wind (OSW) facilities on coastal habitats along the U.S. Atlantic coast in support of National Environmental Policy Act (NEPA) documentation for OSW facilities. The intent of this white paper is to provide a mechanism to assist in efforts supporting a more “efficient and coordinated permitting process for offshore wind energy developments.” To this end, the final product is an effects matrix that generates a table of overall effects using intensity, context, and duration, as well as ranking (thresholds) for impacts. While habitat loss has been identified as an issue in the literature reviewed as part of this white paper, most of the focus is on offshore and marine species habitat loss and effects. A review of the few Bureau of Ocean Energy Management (BOEM) documents prepared to date for OSW facilities indicated potential impacts of COP activities on coastal habitats were considered negligible to minor in most cases as a result of landfall occurring in already developed locations or existing rights-ofway. The use of existing rights-of-way is likely in future OSW projects to the extent feasible. The extremely small footprint of areas of potential impacts on coastal habitats, when compared with the large marine footprint of the offshore wind turbine generator components, may also influence the evaluation of impacts. Potential impacts on onshore resources were addressed briefly for terrestrial birds and mammals with respect to substation construction and overhead transmission lines in several instances in literature reviewed.
... These PUs have exhibited a significant expansion rate, with a daily increase of 11.36 cm 2 /day. Since their initial planting, they have produced approximately 48,000 new shoots, the majority of which belong to the climax seagrass species T. testudinum (Zieman, 1982). The PUs have produced new shoots and facilitated the sexual reproduction of seagrass meadows, as multiple flowers, fruits, and seeds were observed in the PUs, contributing to the enhancement of genetic diversity within the meadow (Fig. S2). ...
Article
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Background Seagrass meadows, known for providing essential ecosystem services like supporting fishing, coastline protection from erosion, and acting as carbon sinks to mitigate climate change effects, are facing severe degradation. The current deteriorating state can be attributed to the combination of anthropogenic activities, biological factors ( i.e ., invasive species), and natural forces ( i.e ., hurricanes). Indeed, the global seagrass cover is diminishing at an alarming mean rate of 7% annually, jeopardizing the health of these vital ecosystems. However, in the Island Municipality of Culebra, Puerto Rico, losses are occurring at a faster pace. For instance, hurricanes have caused over 10% of cover seagrass losses, and the natural recovery of seagrasses across Culebra’s coast has been slow due to the low growth rates of native seagrasses ( Thalassia testudinum and Syringodium filiforme ) and the invasion of the invasive species Halophila stipulacea . Restoration programs are, thus, necessary to revitalize the native seagrass communities and associated fauna while limiting the spread of the invasive species. Methods Here, we present the results of a seagrass meadow restoration project carried out in Punta Melones (PTM), Culebra, Puerto Rico, in response to the impact of Hurricanes Irma and María during 2017. The restoration technique used was planting propagation units (PUs), each with an area of 900 cm ² of native seagrasses Thalassia testudinum and Syringodium filiforme , planted at a depth between 3.5 and 4.5 m. A total of 688 PUs were planted between August 2021 and August 2023, and a sub-sample of 88 PUs was monitored between August 2021 and April 2023. Results PUs showed over 95% of the seagrass survived, with Hurricane Fiona causing most of the mortalities potentially due to PUs burial by sediment movement and uplifting by wave energy. The surface area of the planting units increased by approximately 200% ( i.e ., 2,459 cm ² ), while seagrass shoot density increased by 168% ( i.e ., 126 shoots by PU). Additionally, flowering and fruiting were observed in multiple planting units, indicating 1) that the action taken did not adversely affect the PUs units and 2) that the project was successful in revitalizing seagrass populations. The seagrass restoration project achieved remarkable success, primarily attributed to the substantial volume of each PUs. Likely this high volume played a crucial role in facilitating the connection among roots, shoots, and microfauna while providing a higher number of undamaged and active rhizome meristems and short shoots. These factors collectively contributed to the enhanced growth and survivorship of the PUs, ultimately leading to the favorable outcome observed in the seagrass restoration project.
... They have important donation in the feeding production, their habitats are highly productive (Wood et al., 1969;McRoy and Helfferich, 1977;McRoy and Helfferich, 1980;Zieman and Wetzel, 1980;Duarte and Chiscano, 1999) [35,23,24,38,4] , and have high biodiversity (Loneragan et al., 1994) [20] . Seagrasses are considered as feeding, nursery, shelter and refuge areas for many organisms (Zieman, 1982;Fortes, 1986) [36,9] . Seagrass beds have a potential to control chemical and physical parameters in the water (Radke, 2000) [29] . ...
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The qualitative and quantitative data of seagrass meadows using line transects and quadrates were collected at each of Marsa Bashayer, Marsa Dama Dama, Eastern part of Port Sudan Harbour (Green Area), Northern part of Port Sudan Harbour (Shipyard), Marsa Halout and Dungonab Bay in the Sudanese Red Sea Coast. The seagrass species were identified and their distribution, shoots density, shoots height, and above ground biomass were measured. Water depth and transparency, sediment thickness and grain size were analyzed. Ten species of seagrasses were encountered (Thalassia hemprichii, Halophila ovalis, Halophila minor, Halophila stipulacea, Enhalus acoroides, Halodule uninervis, Syringodium isoetifolium, Thalassodendron ciliatum, Cymodocea rotundata and Cymodocea serrulata) for the first time in the Sudanese Red Sea coast. The mean shoot density varied between 2 and 8050 shoot/m 2. The mean shoot height ranged between 1 and 72 cm. and the mean above ground biomass ranged between 8.9 and 985.9 g dry weight/m 2 .Generally, sites showed no major physical parameters differences among them excluding the water transparency which was lower in sites in the vicinity of high coastal activities area.
... Descriptive research on seagrass communities has established the great abundance and richness of resident fauna inside the seagrass beds (Petersen 1913, Orth 1973Zieman 1982). ...
... However, the lifespan of the late-successional seagrass T. testudinum is longer, which can avoid the expansion of H. wrightii to the space of T. testudinum [36]. The dominance of the larger seagrass T. testudinum is possibly due to the shading of the light reaching the smaller seagrass H. wrightii [37]. H. wrightii is capable of adapting to low irradiance [38], so H. wrightii is often observed growing in mixed seagrass beds, as in our case of H. uninervis in southern Taiwan [39]. ...
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Seagrass beds are major blue carbon ecosystems. Climate change-associated factors may change the seagrass community and affect the capacity of carbon sequestration. To explore the possible effects of warming, higher precipitation levels and/or sea level rise on seagrasses, the spatial and seasonal dynamics in shallow seagrass beds comprising the late-successional seagrass Thalassia hemprichii and the early-successional seagrass Halodule uninervis were tracked. The high-resolution mapping of seagrass biomass dynamics showed that T. hemprichii was the dominant species in the study sites year round, as the space occupation by the larger seagrass T. hemprichii was more efficient than that by the smaller seagrass H. uninervis. The space occupation by both species in the low-elevation site was more efficient than in the high-elevation site. In the low-elevation site, while the dominance of the faster growing seagrass H. uninervis was increasing, the dominance of T. hemprichii was decreasing. This suggested that the carbon sequestration capacity of the seagrass beds will decrease, as T. hemprichii was capable of storing more carbon in the sediments. In the high-elevation site, however, the distribution of both species was distinct and showed a clear seasonal succession. The dominance of H. uninervis moved to shallower water in the wet season and then moved back to deeper water in the dry season. Our observations suggested that four possible mechanisms might be involved in the dominance shift in the shallow seagrass beds: (1) the deeper water in the low-elevation site or the higher precipitation levels in the wet season might reduce the drought stress of H. uninervis at low tide and enhance the competition of H. uninervis over T. hemprichii; (2) the growth of H. uninervis might be stimulated more by the flushing of land-based nutrients caused by the higher precipitation rates in the wet season; (3) in the high-elevation site, the faster flow velocity and frequently disturbed sediments in the dry season might constrain the further expansion of H. uninervis to shallower water; (4) the faster flow velocity in the high-elevation site might reduce the impacts of periphyton overgrowth on T. hemprichii and maintain the dominance of T. hemprichii in the community. Our results suggest seagrasses will not necessarily respond to fluctuating environments in the same way in the coming decades.
... The optimal habitat for spotted seatrout is predicted to decrease with salinity increases, while habitat for spiny lobster may increase with rising salinities [32]. Decreases in freshwater flows to Florida Bay led to changes in the composition of seagrass communities, which may have been associated with declines in game fish populations [29,79]. Higher salinities under climate change could potentially increase the risk of seagrass die-offs, seagrass wasting disease, and algal blooms in the bay [21][22][23]. ...
Article
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Florida Bay is a large, subtropical estuary whose salinity varies from yearly and seasonal changes in rainfall and freshwater inflows. Water management changes during the 20th century led to a long-term reduction in inflows that increased mean salinity, and the frequency and severity of hypersalinity. Climate change may exacerbate salinity conditions in Florida Bay; however, future salinity conditions have not been adequately evaluated. Here, we employed a Multilayer Feedforward Artificial Neural Network model to develop baseline salinity models for nearshore and offshore sites. Then, we examined the impacts of climate change on salinity using forecasted changes in various input variables under two climate change scenarios, representative concentration pathways (RCP) 4.5 and 8.5. Salinity could rise by 30% and 70% under the RCP4.5 and RCP8.5 forecasts, respectively. Climate change affected nearshore salinity significantly more, which rapidly fluctuated between mesohaline (5 to 18 PSU) and metahaline (40 to 55 PSU) to hypersaline conditions (>55 PSU). Offshore salinities ranged between euhaline (30 to 40 PSU) to metahaline (40 to 55 PSU) conditions. Our study suggests that increased freshwater flow would help maintain suitable estuarine conditions in Florida Bay during climate change, while our novel modeling approach can guide further Everglades restoration efforts.
... Aptly, marine plants and their microbiomes, which would include the Vibrionaceae, are an underexplored treasure trove for the bioprospecting of antimicrobial compounds and other bioactive molecules [24,51]. Although the focus here has been on seagrasses, host-microbe interactions that the Vibrionaceae forms with other aquatic plants should not be overlooked, including salt-tolerant freshwater plants (the halophyte Ruppia maritima) and mangroves [55]. Since there are a few Vibrionaceae members that can persist at low salinities, the relationships this taxonomic family engages in with freshwater plants should also receive further rigorous treatment. ...
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The Vibrionaceae encompasses a cosmopolitan group that is mostly aquatic and possesses tremendous metabolic and genetic diversity. Given the importance of this taxon, it deserves continued and deeper research in a multitude of areas. This review outlines emerging topics of interest within the Vibrionaceae. Moreover, previously understudied research areas are highlighted that merit further exploration, including affiliations with marine plants (seagrasses), microbial predators, intracellular niches, and resistance to heavy metal toxicity. Agarases, phototrophy, phage shock protein response, and microbial experimental evolution are also fields discussed. The squid–Vibrio symbiosis is a stellar model system, which can be a useful guiding light on deeper expeditions and voyages traversing these “seas of interest”. Where appropriate, the squid–Vibrio mutualism is mentioned in how it has or could facilitate the illumination of these various subjects. Additional research is warranted on the topics specified herein, since they have critical relevance for biomedical science, pharmaceuticals, and health care. There are also practical applications in agriculture, zymology, food science, and culinary use. The tractability of microbial experimental evolution is explained. Examples are given of how microbial selection studies can be used to examine the roles of chance, contingency, and determinism (natural selection) in shaping Earth’s natural history.
... With 90% of the carbon in seagrass ecosystems being seagrass biomass, we estimated BGC by applying an aboveground to belowground (AGC:BGC) ratio of 1:3 based on a study of a T. testudinum-dominated seagrass meadow in an estuary with similar sedimentary characteristics to St. Joseph Bay (Equation (9) ;Folger, 1972;Zieman, 1975Zieman, , 1982: ...
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Seagrass meadows are degraded globally and continue to decline in areal extent due to human pressures and climate change. This study used the bio-optical model GrassLight to explore the impact of climate change and anthropogenic stressors on seagrass extent, leaf area index (LAI) and belowground organic carbon (BGC) in St. Joseph Bay, Florida, using water quality data and remotely-sensed sea surface temperature (SST) from 2002 to 2020. Model predictions were compared with satellite-derived measurements of seagrass extent and shoot density from the Landsat images for the same period. The GrassLight-derived area of potential seagrass habitat ranged from 36.2 km2 to 39.2 km2, averaging 38.0 ± 0.8 km2 compared to an observed seagrass extent of 23.0 ± 3.0 km2 derived from Landsat (range = 17.9-27.4 km2). GrassLight predicted a mean seagrass LAI of 2.7 m2 leaf m-2 seabed, compared to a mean LAI of 1.9 m2 m-2 estimated from Landsat, indicating that seagrass density in St. Joseph Bay may have been below its light-limited ecological potential. Climate and anthropogenic change simulations using GrassLight predicted the impact of changes in temperature, pH, chlorophyll a, chromophoric dissolved organic matter and turbidity on seagrass meadows. Simulations predicted a 2-8% decline in seagrass extent with rising temperatures that was offset by a 3-11% expansion in seagrass extent in response to ocean acidification when compared to present conditions. Simulations of water quality impacts showed that a doubling of turbidity would reduce seagrass extent by 18% and total leaf area by 21%. Combining climate and water quality scenarios showed that ocean acidification may increase seagrass productivity to offset the negative effects of both thermal stress and declining water quality on the seagrasses growing in St. Joseph Bay. This research highlights the importance of considering multiple limiting factors in understanding the effects of environmental change on seagrass ecosystems.
... In large and robust species like turtlegrass, the majority of the biomass is found belowground in the form of an extensive root and rhizome system (Zieman and Zieman 1989;Kaldy and Duntn 2000). Belowground biomass was therefore estimated based on the 1:3 ratio for aboveground and belowground biomass due to the dominance of the seagrass meadows by turtlegrass (Zieman 1975(Zieman , 1982(Zieman , 1989 and the sedimentary character of St. Joseph Bay (Eq. ...
Article
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Seagrasses are globally recognized for their contribution to blue carbon sequestration. However, accurate quantification of their carbon storage capacity remains uncertain due, in part, to an incomplete inventory of global seagrass extent and assessment of its temporal variability. Furthermore, seagrasses are undergoing significant decline globally, which highlights the urgent need to develop change detection techniques applicable to both the scale of loss and the spatial complexity of coastal environments. This study applied a deep learning algorithm to a 30-year time series of Landsat 5 through 8 imagery to quantify seagrass extent, leaf area index (LAI), and belowground organic carbon (BGC) in St. Joseph Bay, Florida, between 1990 and 2020. Consistent with previous field-based observations regarding stability of seagrass extent throughout St. Joseph Bay, there was no temporal trend in seagrass extent (23 ± 3 km ² , τ = 0.09, p = 0.59, n = 31), LAI (1.6 ± 0.2, τ = -0.13, p = 0.42, n = 31), or BGC (165 ± 19 g C m ⁻² , τ = - 0.01, p = 0.1, n = 31) over the 30-year study period. There were, however, six brief declines in seagrass extent between the years 2004 and 2019 following tropical cyclones, from which seagrasses recovered rapidly. Fine-scale interannual variability in seagrass extent, LAI, and BGC was unrelated to sea surface temperature or to climate variability associated with the El Niño-Southern Oscillation or the North Atlantic Oscillation. Although our temporal assessment showed that seagrass and its belowground carbon were stable in St. Joseph Bay from 1990 to 2020, forecasts suggest that environmental and climate pressures are ongoing, which highlights the importance of the method and time series presented here as a valuable tool to quantify decadal-scale variability in seagrass dynamics. Perhaps more importantly, our results can serve as a baseline against which we can monitor future change in seagrass communities and their blue carbon.
... This delay in disturbance may have allowed Rankin to begin recolonizing the benthos as illustrated by the recovery of seagrass cover (by mostly H. wrightii) to a BB score of 2.5 before the sediment plume entered Rankin. Recolonization followed traditional models of SAV succession, wherein macroalgae colonize the bare sediment and then H. wrightii replaces the macroalgae (Den Hartog, 1979;Zieman, 1982). Due to the known function of seagrass habitats for sediment stabilization and deposition in coastal environments (Bos et al., 2007), we hypothesize that the establishment of H. wrightii within Rankin helped stabilize the sediment. ...
... Mangroves, primarily red mangrove (Rhizophora mangle) and black mangrove (Avicennia germinans), cover the shorelines and the shallow waters contain extensive seagrass meadows primarily comprising of turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme), and shoal grass (Halodule wrightii). Mangrove swamps and seagrass beds are extremely productive ecosystems, even rivaling the net primary productivity of agriculture (Odum, McIvor, and Smith 1982, 19;Zieman 1982). The Calusa took advantage of these highly productive ecosystems, centering their economies on the resources found within these environments. ...
Article
The Pineland Site Complex, 8LL1902, is a large archaeological complex of middens, mounds, and other topographic features located in coastal, southwestern Florida. It was occupied from approximately AD 50 and was a major Calusa town at European contact. We combine extant research from this well-preserved site complex with new chronological and zooarchaeological analyses to provide new insight into the relationship between fisher-gatherer-hunter subsistence economies and small-scale but impactful climatic change. We identify and record the localized environmental changes co-occurrent with the global climatic episode known as the Little Ice Age (AD 1200–1850). By combining Bayesian statistical analyses of radiocarbon dates with zooarchaeological analyses of a waterlogged, shoreline midden we generate a high-resolution, localized view of socioecological interactions at the Pineland Site ca. AD 1200–1500. Such micro-scale temporal perspectives are necessary to achieve high resolution, localized histories of human-climate dynamics.
... Pioneer species within seagrass meadows are generally small and fast growing, whereas climax species are large and slow-growing. If conditions are not extrinsically disturbed, succession should follow a direction, which has been long believed to end in a monospecific meadow formed by a climax seagrass species (Moliner and Picard, 1952;Aleem, 1955;den Hartog, 1971den Hartog, , 1977Zieman, 1982). Competitive interactions between pioneer and climax seagrass species are the mechanisms driving the course of the succession (Connell and Slatyer, 1977;Tilman, 1994). ...
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Tropical seagrass meadows are formed by an array of seagrass species that share the same space. Species sharing the same plot are competing for resources, namely light and inorganic nutrients, which results in the capacity of some species to preempt space from others. However, the drivers behind seagrass species competition are not completely understood. In this work, we studied the competitive interactions among tropical seagrass species of Unguja Island (Zanzibar, Tanzania) using a trait-based approach. We quantified the abundance of eight seagrass species under different trophic states, and selected nine traits related to light and inorganic nutrient preemption to characterize the functional strategy of the species (leaf maximum length and width, leaves per shoot, leaf mass area, vertical rhizome length, shoots per meter of ramet, rhizome diameter, roots per meter of ramet, and root maximum length). From the seagrass abundance we calculated the probability of space preemption between pairs of seagrass species and for each individual seagrass species under the different trophic states. Species had different probabilities of space preemption, with the climax species Thalassodendron ciliatum, Enhalus acoroides, Thalassia hemprichii, and the opportunistic Cymodocea serrulata having the highest probability of preemption, while the pioneer and opportunistic species Halophila ovalis, Syringodium isoetifolium, Halodule uninervis, and Cymodocea rotundata had the lowest. Traits determining the functional strategy showed that there was a size gradient across species. For two co-occurring seagrass species, probability of preemption was the highest for the larger species, it increased as the size difference between species increased and was unaffected by the trophic state. Competitive interactions among seagrass species were asymmetrical, i.e., negative effects were not reciprocal, and the driver behind space preemption was determined by plant size. Seagrass space preemption is a consequence of resource competition, and the probability of a species to exert preemption can be calculated using a trait-based approach.
... This delay in disturbance may have allowed Rankin to begin recolonizing the benthos as illustrated by the recovery of seagrass cover (by mostly H. wrightii) to a BB score of 2.5 before the sediment plume entered Rankin. Recolonization followed traditional models of SAV succession, wherein macroalgae colonize the bare sediment and then H. wrightii replaces the macroalgae (Den Hartog, 1979;Zieman, 1982). Due to the known function of seagrass habitats for sediment stabilization and deposition in coastal environments (Bos et al., 2007), we hypothesize that the establishment of H. wrightii within Rankin helped stabilize the sediment. ...
Article
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Seagrasses are threatened worldwide due to anthropogenic and natural disturbances disrupting the multiple feedbacks needed to maintain these ecosystems. If the disturbance is severe enough, seagrass systems may undergo a regime shift to a degraded system state that is resistant to recovery. In Florida Bay, Florida, United States, two recent, large-scale disturbances (a drought-induced seagrass die-off in 2015 and Hurricane Irma in 2017) have caused 8,777 ha of seagrass beds to degrade into a turbid, unvegetated state, causing a large sediment plume. Using satellite imagery digitization and long-term seagrass cover data, we investigate the expansion of this sediment plume between 2008 and 2020 and the potential interaction of this sediment plume with seagrass recovery in two focal basins in Florida Bay affected by the die-off, Johnson and Rankin. The average size of the sediment plume increased by 37% due to the die-off and Hurricane Irma, increasing from an average of 163.5 km² before the disturbances to an average of 223.5 km². The expansion of the plume was basin-specific, expanding into Johnson after the 2015 seagrass die-off with expansive and long-lasting effects, but only expanding into Rankin after Hurricane Irma with less severe and short-term effects. Furthermore, the sediment plume was negatively correlated with seagrass cover in Johnson, but held no relationship with seagrass cover in Rankin. Thus, different disturbances can act upon seagrass ecosystems at varying scales with varying consequences. This study illustrates the advantage of combining satellite imagery with field data to monitor disturbances as well as highlights the importance of investigating disturbances of seagrass ecosystems at various scales to comprehend seagrass resilience in the context of future extreme events.
... Distributions among reaches also were influenced by salinities, because reaches differ in the amount of fresh water and oceanic water they receive via tributaries, canals, and inlets. In fact, Hw, the most widely distributed seagrass in the IRL, has been shown to tolerate 5-80 psu (Phillips 1960, Montague and Ley 1993, Lirman and Cropper 2003, whereas Tt and Sf, which occupied the reaches affected by inlets, have been reported to grow best in stable salinities of 20-60 psu (Zieman 1982, Lewis et al. 1985, Montague 1989, Tomasko and Hall 1999, Irlandi et al. 2002. Distributions among reaches were less likely to be influenced by light availability, but this parameter strongly influenced distributions along depth gradients. ...
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Seven species of seagrass have been found in the Indian River Lagoon (IRL), making it an unusually diverse location at the global scale. From 1994 to 2019, the lagoon-wide distribution of these species reflected variations in temperature, salinity, and the availability of light at depth, which were related to latitudinal differences in hydrology and hydrodynamics along the IRL. In general, species richness was higher near the four southern inlets, and fewer species were found in areas with longer residence times for water. At a finer scale, the distribution of species varied among depths, with the greatest number of species found at mid-depths (~0.4-0.9 m). Prior to 2011, these patterns remained relatively consistent for~40 years, but several, intense and prolonged phytoplankton blooms disrupted them. The areal extent of all seagrasses decreased by over 50%, the offshore ends of canopies moved shoreward and shallower, distributions of species along gradients of latitude and depth were disrupted, and mean percent cover decreased. Major changes in distribution and abundance of seagrasses arose when salinity, temperature, and availability of light at depth exceeded limits derived for each species. These substantial and widespread changes engendered concerns for recovery or rehabilitation of seagrasses in the lagoon.
... o D'un point de vue biologique, les herbiers abritent une biodiversité remarquable en procurant des zones refuges, des sites de reproduction ou encore des nurseries favorables à la biocénose benthique (Zieman 1982, Dawes et al. 1995, Duffy et al. 2003, Kenworthy et al. 2006, Walker & Kendrick 2006, Touchette 2007, Hovel & Regan 2008, Hughes et al. 2009 ...
Technical Report
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Dark-bellied Brent Goose as a biodincator of intertidal ecosystems
... o D'un point de vue biologique, les herbiers abritent une biodiversité remarquable en procurant des zones refuges, des sites de reproduction ou encore des nurseries favorables à la biocénose benthique (Zieman 1982, Dawes et al. 1995, Duffy et al. 2003, Kenworthy et al. 2006, Walker & Kendrick 2006, Touchette 2007, Hovel & Regan 2008, Hughes et al. 2009). ...
Technical Report
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Identification and caracthirization of South Marenne-Oléron Zostera noltei bed
... Si les herbiers à Zostères ont fait l'objet de travaux de recherches dès le début du siècle dernier (Fischer-Piette, Heim & Lami, 1932;Duncan, 1933;Cottam, Lynch & Nelson, 1944), ce n'est toutefois que récemment que leur importance écologique fondamentale au sein des écosystèmes marins a réellement été considérée (Davison & Hughes, 1998;Duarte, 2000;Duffy, Richardson & Canuel, 2003;Borum et al., 2004;Kenworthy et al., 2006;Valentine & Duffy, 2006;Larkum et al., 2007;Hemminga & Duarte, 2008;Hughes et al., 2009 o D'un point de vue biologique, les herbiers abritent une biodiversité remarquable en procurant des zones refuges, des sites de reproduction ou encore des nurseries favorables à la biocénose benthique (Zieman, 1982;Dawes, Hansiak & Kenworthy, 1995;Duffy et al., 2003;Kenworthy et al., 2006;Walker & Kendrick, 2006;Touchette, 2007;Hovel & Regan, 2008;Hughes et al., 2009). ...
... Ruppia maritima seeds were abundant in cores from Lakes Tohopekaliga and East Tohopekaliga prior to 1880. Although Ruppia is often described as an estuarine plant in areas of lower salinity, it is actually a freshwater plant that has pronounced salinity tolerance, and it occurs in clear waters <2.0 m deep (Zieman 1982, Kantrud 1991. We have collected Ruppia, for example, in the littoral zone of a freshwater Florida lake that has a specific conductance of about 1500 lS/cm. ...
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Whitmore TJ, Riedinger-Whitmore MA, Reed, ZE, Curtis, JH, Yang H, Evans DE, Cropper NR, Alvarado KS, Lauterman FM, Scott A, Leonard DE, Franklin DL. 2020. Paleolimnological assessment of six lakes on the Kissimmee Chain, with implications for restoration of the Kissimmee–Okeechobee–Everglades systerm, Florida, USA. Lake Resrv Manage. XX:XX–XX. The Kissimmee Basin in south central Florida contains a large, freshwater network that includes the Kissimmee River and nearly 2 dozen lakes that are headwaters of the Florida Everglades. Management of these lakes is an important part of Everglades restoration. We report a paleolimnological investigation of 6 lakes in the Upper Kissimmee Basin. Engineering activities connected the lakes and permanently altered hydrology in the 19th and 20th centuries. The lakes were naturally meso-eutrophic, but changes in lake levels and nutrient loading contributed to different degrees of eutrophication. Cyanobacteria were present historically at low levels in Lakes East Tohopekaliga, Cypress, and Tohopekaliga, but increased during the 20th century. Lake Jackson lacked cyanobacteria until recently, but Lakes Kissimmee and Marian have had high levels of cyanobacteria since predisturbance times. Profound changes in the lakes occurred after engineering activities eliminated natural large fluctuations in water levels that periodically dried large portions of the basins. Salt-tolerant biological indicators previously alternated with freshwater organisms. Large water-level fluctuations moderated aquatic-plant standing crops and reduced organic matter accumulation. Lakes Kissimmee and Marian showed greatest evidence of former associated wetlands, but lacked large variations in water levels. We recommend disconnecting these lakes from each other and from the Kissimmee River to reestablish large, natural fluctuations in water levels that were part of healthy ecosystem function. Former wetlands should be restored to slow the downstream cascade of nutrients to Lake Okeechobee and the Everglades. This study demonstrates that paleolimnology is useful for assessing hydrological changes that potentially affect lake restoration efforts.
... An appropriate candidate for seagrass transplantation in the nGoM is shoalgrass (Halodule wrightii), a tropical/subtropical species whose distribution extends throughout the GoM, Caribbean, Atlantic Coast of the U.S. and Bermuda (van Tussenbroek, Barba Santos, Ricardo Wong, van Dijk, & Waycott, 2010). Shoalgrass is characterized as a pioneer species that readily colonizes unconsolidated sediments (Zieman, 1982) with a rapid vegetative expansion rate (Marbá & Duarte, 1998) that serves to expedite restoration site establishment. It is also ideal for transplantation into dynamic, estuarine influenced coastlines due to the species' wide salinity tolerance range (Lirman & Cropper, 2003;Mazzotti et al., 2007). ...
Article
Concern for conservation of seagrass habitat has prompted international transplantation‐style restoration efforts. A recent review of these restoration efforts has highlighted the low success associated with small‐scale restorations, yet scaling up transplantation effort may be too costly for underfunded regions. Small‐scale transplant survival can be enhanced with alleviation of two underlying issues: restoration site selection and donor site selection. To investigate appropriate donor source selection, donor site environmental influence on seagrass ( Halodule wrightii ) transplant survival was examined by transplanting donor cores from two environmentally disparate sites to a transplantation site with limited environmental uncertainties. Donor sites were chosen to represent either end of a benthic light gradient (high versus low) to elucidate seagrass resilience to transplantation stress, with respect to donor site conditions. After total loss of the first trial, a second trial was conducted with stabilizing mesh placed over transplants to reduce stingray bioturbation. The second trial resulted in 100% survival of high light transplants after 12 months and moderate survival (30–60%) of low light transplants for the first six months. At 18 months, the second trial ended after sediment burial from a hurricane. One year post‐burial, a patch of H. wrightii recovered at the high light transplant site; after six years the patch expanded to approximately 74 m ² , an area 37‐fold larger than originally planted. Results from this transplant experiment provide evidence that donor environment plays a role in transplant resilience. The transplants sourced from high light had 47% greater leaf area per shoot, were more resistant to transplantation stress, and recovered following an extreme event relative to low light transplants. Therefore, selection of donor plants with more resilience features, a transplantation site with limited environmental uncertainties, and adaptive intervention can enhance seagrass resilience at a small planting scale.
... These below-ground tissues are subjected to less grazing and exportation and are protected from physical removal and disturbances, which would promote further sequestration in the sediments (Macreadie et al., 2015;Trevathan-Tackett et al., 2017). Due to the low decomposition rate of below-ground tissues, the tissues appeared to be stored in sediments for many years (Zieman, 1982;Kenworthy and Thayer, 1984;Mateo et al., 2006). The heavy metals combined with organic matters stored in the sediments will be in the stable status, thereby reducing metal bioavailability and preventing migration through the sediments (Livens, 1991;Vervaeke et al., 2004). ...
Article
Although seagrasses can incorporate heavy metals from the marine environment, few studies have been conducted on heavy metal uptake and phytoremediation potential by seagrass transplants in the heavy metal contaminated sediments. Zostera marina shoots were transplanted in two polluted bay systems on Korean coasts to evaluate the heavy metal contaminations in sediments and the possibility of using Z. marina transplants as a bioindicator and phytoremediation agent. The major concentrated metals in sediments were As, Cu, Fe, and Pb in Jaran Bay, and Cd, Co, Zn, and Hg in Onsan Bay. The Co, Zn, Pb, and Hg concentrations in Z. marina tissues reflected the sediment heavy metal concentrations, and thus the tissue heavy metal concentrations may be used as bio-indicators of the metal contaminations. Since Z. marina transplants accumulated a great amount of heavy metals in their tissues, they may have the phytoremediation potential for the heavy metal contaminated sediments.
... FIGURE 4 | Model of Caribbean seagrass meadow development during succession and degradation as depicted across different CARICOMP sites. Succession initiates with pioneering rhizophytic algae (RA), followed by faster-growing seagrasses Halodule wrightii (Hw) and Syringodium filiforme (Sf), and a vegetation dominated by the robust and slow-growing Thalassia testudinum (Tt) as climax stage (Zieman, 1982;Williams, 1990). The dominant species at each development stage is given, but mixture with species from other stages usually occurs. ...
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Caribbean Coastal Marine Productivity (CARICOMP) was a basin-wide cooperative, international network of marine laboratories established in 1985. Recognizing major trends of change in coastal ecosystems and the importance of the linkages among them, our goal was to monitor synoptically with standardized methods the physical environment and to document trends in measures of the structure and functioning of coral reefs, seagrasses and mangroves. Between 1985 and 1993, the CARICOMP Steering Committee established a data management center and wrote a methods manual. Marine laboratories joined the program by appointing a Site Director and signing an agreement specifying the cost sharing and responsibilities of the laboratory. With significant outside funding in 1992, the program became fully functional and ultimately more than 30 institutions in 21 Caribbean countries participated. Monitoring lasted from 1992 to 2007, spanning many technological advances including the internet, automated in situ data logging and remote sensing. Annual CARICOMP meetings, organized at a different laboratory each year, were essential in standardization of methods and maintaining interest. Open access to the data was a goal from the start, although the members imposed an embargo to allow time to publish major results. At some of the sites, monitoring continues to this day, generating among the longest coastal monitoring data sets in the Caribbean, and possibly in the world. Over time, multi-authored papers were prepared for the Proceedings of the International Coral Reef Symposia and other journals, and independent scientists drew on the open database for regional analyses of ecosystem trends. Recently, active members have written summary papers based on the monitoring data covering physical parameters, coral reefs, seagrasses, and mangroves. Overall, the data reveal major differences across the region and changing rates and trends showing the dynamism and vulnerability of coastal ecosystems. The longer the monitoring continues, the more valuable the dataset becomes as a tool to discern the underlying factors driving the structure and functioning of Caribbean coastal ecosystems. Several recent workshops have concluded that the need for regionally cooperative monitoring and research has never been greater.
... In contrast, Thalassia testudinum Banks ex König is large-bodied, long-lived, dioecious, and the dominant subtidal seagrass species in tropical and subtropical waters of the western Atlantic and Caribbean region (Williams, 1990;Zieman, 1982). T. testudinum generally grows subtidally, in monotypic and mixed-species beds, and within their shared geographic distribution H. johnsonii and T. testudinum do not usually grow together. ...
Article
Mechanisms for carbon uptake in the small-bodied Halophila johnsonii and large-bodied Thalassia testudinum were compared using photosynthesis measurements (oxygen flux) with, and without, the extracellular carbonic anhydrase inhibitor acetazolamide (AZ) and TRIS buffer. Our results indicated T. testudinum and H. johnsonii both utilize external membrane-bound carbonic anhydrase to facilitate dehydration of HCO3− into CO2(aq). T. testudinum also utilizes an active proton (H+) pump to create localized H+ gradients within the boundary layer and it derives a larger portion of photosynthetic carbon from bicarbonate than H. johnsonii. Stable carbon isotope composition (δ13C) of T. testudinum and H. johnsonii leaves under high and reduced irradiance were also compared to evaluate photosynthetic carbon use. Isotope ratios of H. johnsonii were significantly more negative than T. testudinum at a high-light field site (−10.44 ± 0.26‰ vs −9.25 ± 0.25‰). In contrast, there was no significant difference in isotope ratios between species for plants maintained in a greenhouse under reduced photosynthetically active radiation. This suggests photosynthesis of T. testudinum is more carbon limited or more reliant on bicarbonate for photosynthesis than H. johnsonii under high-light conditions. Although photosynthesis of both species is expected to increase in response to greater CO2(aq) availability, ocean acidification and its CO2(aq) enrichment of seawater may have greater benefits for H. johnsonii compared to T. testudinum, whose photosynthesis relies more heavily on HCO3− use.
... Species composition of seagrass beds in Florida is highly influenced by salinity, with increases in the amount and variability in runoff leading to a change from T. testudinum-dominated seagrass beds to ones dominated by H. wrightii (Fourqurean, Boyer, Durako, Hefty, & Peterson, 2003;Lirman et al., 2014). In fact, decreases in freshwater flow into Florida Bay caused by the South Florida water management system played a major role in a shift from a H. wrightiidominated state in the 1970s to a T. testudinum-dominated state in the 1980s (Zieman, 1982). The reduction in freshwater flow and changes in hydrology have been linked to the mass mortality of seagrasses in Florida Bay in 1987-91 and, more recently, in 2015-16 (Hall et al., 2016). ...
... The decrease in freshwater inflow has also caused changes in benthic community structure (Brewster-Wingard and Ishman, 1999;Halley and Roulier, 1999). Specifically, the reduction in freshwater runoff and resulting high salinity has led to "marinization" and increased homogeneity in the vegetation in the system, causing T. testudinum to become more widespread and abundant as other seagrasses have declined in abundance (Zieman, 1982;Fourqurean and Robblee, 1999). ...
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... However, Lipkin (1979) recorded over 100 kg dry weight/m 2 from another site in the Gulf of Aqaba.Compared with intertidal mud-flats, sand-flats and salt marsh habitats, seagrass beds often accommodate higher species richness, abundance, biomass and production of macroinvertebrates(Heck et al., 1995). Descriptive research on seagrass communities has established the great abundance and richness of resident faunas inside the beds(Zieman, 1982). In their studies on the associated organisms with the seagrass from the Gulf of Aqaba Wahbeh (1981) and Fouda (1993) recorded 49 species. ...
... Sampling intervals were short at the beginning to better capture N dynamics during early stages of decomposition. Because leaves of T. testudinum take approximately 60 days to decompose (Zieman 1982;Darnell 2015), the retrieval dates span 77 days to allow for the process to be completed. ...
... Sampling intervals were short at the beginning to better capture N dynamics during early stages of decomposition. Because leaves of T. testudinum take approximately 60 days to decompose (Zieman 1982;Darnell 2015), the retrieval dates span 77 days to allow for the process to be completed. ...
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