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Title: Alkaline Phosphatase Activity of Seagrass and Water Column Fractions in Florida Bay.
Creator: Kletou, Demetris, Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Few phosphorus (P) depleted coastal marine ecosystems have been examined for their capacity to hydrolyze phosphomonoesters (PMEs). The purpose of this study was to examine seasonal APA partitioning between water column fractions (phytoplankton, bacteria and freely dissolved) and benthic autotrophs in Florida Bay, a P limited shallow estuary using low fluorescent substrate (MUF-P) concentrations (≤2.0 μm). APA was higher at the western and northcentral (751 and 695 nmol L^-1 h^-1) sites and...
Show moreFew phosphorus (P) depleted coastal marine ecosystems have been examined for their capacity to hydrolyze phosphomonoesters (PMEs). The purpose of this study was to examine seasonal APA partitioning between water column fractions (phytoplankton, bacteria and freely dissolved) and benthic autotrophs in Florida Bay, a P limited shallow estuary using low fluorescent substrate (MUF-P) concentrations (≤2.0 μm). APA was higher at the western and northcentral (751 and 695 nmol L^-1 h^-1) sites and driven by cyanobacterial blooms, compared to the P limited northeastern (359 nmol L^-1 h^-1) site The free dissolved fraction (<0.2 μm) accounted for the most APA (~50%), followed by the phytoplankton (>1 μm; 30%) and bacteria fraction (<0.2-> 1.2 μm; 8%). Thaiassia testudinum leaves with their associated epiphytes contributed modestly to water column APA (14 and 20%), and only during non-bloom conditions. Rapid hydrolysis of PMEs (undetected in most samplings) in Florida Bay is probably driven by high concentration of organic substrates for microbial and cyanobacterial activity which results from the close association of the shallow water column with the underlying seagrass community and adjacent Everglades wetlands.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00000780
Subject Headings: Coastal ecology--Florida, Coastal zone management--Florida, Estuarine sediments--Florida--Florida Bay, Aquaculture--Environmental aspects--Florida
Format: Document (PDF)

Title: Elevated pCO2 effects on the macroalgal genus Halimeda: Potential roles of photophysiology and morphology.
Creator: Peach, Katherine, Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: While ocean acidification (OA) is predicted to inhibit calcification in marine macroalgae, species whose photosynthesis is limited by current dissolved inorganic carbon (DIC) levels may benefit. Furthermore, variations in macroalgal morphology will likely give rise to a range of OA tolerance in calcifying macroalgae. One genus of calcifying macroalgae that has shown varying species’ tolerance to OA is Halimeda, a major carbonate sediment producer on tropical reefs. Species within this genus...
Show moreWhile ocean acidification (OA) is predicted to inhibit calcification in marine macroalgae, species whose photosynthesis is limited by current dissolved inorganic carbon (DIC) levels may benefit. Furthermore, variations in macroalgal morphology will likely give rise to a range of OA tolerance in calcifying macroalgae. One genus of calcifying macroalgae that has shown varying species’ tolerance to OA is Halimeda, a major carbonate sediment producer on tropical reefs. Species within this genus occupy a range of habitats within tropical environments (reefs and lagoons), illustrating their ability to adapt to diverse environmental conditions (e.g. carbonate chemistry, irradiance). To date it is not clear if morphological and photophysiological diversity in Halimeda will translate to different tolerances to OA conditions (elevated pCO2 and lower pH).
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004621
Subject Headings: Coral reef ecology., Chemical oceanography., Halimeda., Environmental mapping., Plants--Effect of light on., Plant physiology., Photobiology., Carbon cycle (Biogeochemistry)
Format: Document (PDF)

Title: Mechanisms Controlling Distribution of Cosmopolitan Submerged Aquatic Vegetation: A Model Study of Ruppia maritima L. (widgeongrass) at the Everglades-Florida Bay Ecotone.
Creator: Strazisar, Theresa, Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Aquatic plants and submerged aquatic vegetation (SAV) are some of the most wide-ranging species and create important habitat for fish and wildlife in many ecosystems, including highly variable coastal ecotones. Mechanistically understanding factors controlling current distributions of these species is critical to project future distribution and abundance under increasing variability and climate change. I used a population-based approach to quantify the effects of spatial and temporal...
Show moreAquatic plants and submerged aquatic vegetation (SAV) are some of the most wide-ranging species and create important habitat for fish and wildlife in many ecosystems, including highly variable coastal ecotones. Mechanistically understanding factors controlling current distributions of these species is critical to project future distribution and abundance under increasing variability and climate change. I used a population-based approach to quantify the effects of spatial and temporal variability on life history transitions of the SAV Ruppia maritima L. (widgeongrass) in the highly dynamic Everglades-Florida Bay ecotone as a model to (1) examine which life history stages were most constrained by these conditions and (2) determine how management can promote life history development to enhance its distribution, an Everglades restoration target. Ruppia maritima life history transitions were quantified in a series of laboratory and field experiments encompassing a ra nge of abiotic and biotic factors known to affect seagrass and SAV (salinity, salinity variability, temperature, light and nutrients and seed bank recruitment and competition). These studies revealed that R. maritima life history varied east to west across the Everglades ecotone, driven by multiple gradients in abiotic factors that constrained different life history transitions in distinct ways. Based on this examination, persistence of SAV populations from dynamic coastal environments is highly dependent on large reproductive events that produce high propagule densities for recruitment. Large productive meadows of SAV also depend on high rates of clonal reproduction where vegetation completely regenerates in a short amount of time. Therefore, in hydrologically variable systems, maintenance or increases in SAV reproduction is required for population persistence through recruitment. However, SAV communities that do not experience high rates of sexual reproduction are dependent on successful seed germination, seedling and adult survival and clonal reproduction for biomass production and maintenance. Seedling survival and to a lesser extent, adult survival, are bottlenecks that can limit life history transitions under highly variable hydrological conditions. To ensure long-term survival in these communities, management activities that increase survival and successful life history development through these critical stages will be beneficial. If not, SAV populations may become highly reduced and ephemeral, providing less productive habitat.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004549, http://purl.flvc.org/fau/fd/FA00004549
Subject Headings: Coastal zone management, Ruppia maritima -- Ecology -- Everglades National Park (Fla.), Ruppia maritima -- Ecology -- Florida Bay (Fla.), Seagrasses -- Everglades National Park (Fla.), Seagrasses -- Florida Bay (Fla.), Wetland ecology -- Everglades National Park (Fla.), Wetland ecology -- Florida Bay (Fla.)
Format: Document (PDF)

Title: Ocean Acidification Effects on Photosynthesis in Tropical Marine Macroalgae.
Creator: Zweng, Regina C., Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Field data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms,...
Show moreField data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms, irradiance and depth may influence species-specific responses to ocean acidification. Therefore, this thesis aimed to discern carbon use strategies and photosynthetic responses to elevated pCO2 of dominant tropical fleshy and calcareous macroalgae. All species studied were able to utilize HCO3 - for photosynthesis. 33% of calcifying macroalgae and 80% of fleshy macroalgae had increased photosynthetic rates in response to lower pH. Thus, future conditions of OA may perpetuate or exacerbate the abundance of fleshy seaweeds at the expense of calcareous species.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004879, http://purl.flvc.org/fau/fd/FA00004879
Subject Headings: Marine algae--Ecophysiology., Algal communities--Monitoriing., Coral reef ecology.
Format: Document (PDF)

Title: SUSCEPTIBILITY OF RECRUITING SEAGRASS (THALASSIA TESTUDINUM) TO POREWATER H2S IN FLORIDA BAY.
Creator: MacLeod, Kasey, Koch, Marguerite, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: This study investigated the influence of high concentrations of porewater H2S (~100 μM) on recruitment of the tropical dominant seagrass species, Thalassia testudinum, following mortality events or "die-offs" in Florida Bay. Major seagrass die-off events (>50 km2) are occurring globally in coastal regions with mortality frequently linked to hypoxia and sediment-derived hydrogen sulfide (H2S) exposure, a well-known phytotoxin. In tropical carbonate environments, such as Florida Bay, low iron...
Show moreThis study investigated the influence of high concentrations of porewater H2S (~100 μM) on recruitment of the tropical dominant seagrass species, Thalassia testudinum, following mortality events or "die-offs" in Florida Bay. Major seagrass die-off events (>50 km2) are occurring globally in coastal regions with mortality frequently linked to hypoxia and sediment-derived hydrogen sulfide (H2S) exposure, a well-known phytotoxin. In tropical carbonate environments, such as Florida Bay, low iron in sediments promote H2S accumulation and subsequent intrusion into seagrass meristematic tissue through roots, and root-shoot junctions. While H2S intrusion into meristematic tissue is a leading hypothesis for large-scale seagrass mortality events, it is less clear if H2S contributes to a decline in seagrass recruitment following large-scale seagrass die-off events. Herein, I examined tissue stable sulfur isotope signatures (d34S), belowground tissue biomass partitioning, and internal O2/H2S dynamics of newly recovering shoots over seasons at a western Florida Bay site with recurrent die-off events. Tissue results showed less H2S accumulation in tissue samples of shoots recruiting into bare sediment patches compared to tissue samples from adjacent T. testudinum and H. wrightii seagrass meadows. Additionally, internal gas dynamics of recruits showed high pO2 during the day, and no detection of meristematic H2S intrusion, despite meristem hypoxia for several hours during the night. Recruiting shoots consistently have low root biomass, likely contributing to a lack of meristem H2S intrusion, as young, minimally developed, or lack of roots in recruiting shoots limit H2S intrusion. These results lead me to suggest that high H2S levels in porewater of western Florida Bay does not limit T. testudinum recruitment into open bare patches following major die-off events, supported by the recovery, albeit slow, of this species based long-term monitoring of seagrass in the Bay.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014030
Subject Headings: Thalassia testudinum, Seagrasses, Hydrogen sulfide, Pore water
Format: Document (PDF)

Title: Trophic linkages of primary producers and consumers in fringing mangroves of tropical lagoons.
Creator: Kieckbusch, David Keith, Florida Atlantic University, Koch, Marguerite, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Stable carbon and nitrogen isotope ratios were analyzed to investigate the trophic linkages between primary producers and consumers in fringing mangrove ecosystems of The Bahamas and Biscayne Bay, Florida. The isotope ratios, in conjunction with stomach content analysis, were used to trace the flow of organic matter from the primary organic sources (mangroves, seagrass and macro-algae) to primary consumers and ultimately to the gray snapper (Lutjanus griseus). We found the mean delta^13C...
Show moreStable carbon and nitrogen isotope ratios were analyzed to investigate the trophic linkages between primary producers and consumers in fringing mangrove ecosystems of The Bahamas and Biscayne Bay, Florida. The isotope ratios, in conjunction with stomach content analysis, were used to trace the flow of organic matter from the primary organic sources (mangroves, seagrass and macro-algae) to primary consumers and ultimately to the gray snapper (Lutjanus griseus). We found the mean delta^13C value of the primary consumers (-17.1%) to be closely related to the mean values of the macro-algal material (-16.7%) and the seagrass (-10.5%) with very little correlation to the carbon signature of mangroves (mean = -27.4%). Our results suggest the ultimate source of carbon for the primary and secondary consumers, located at our study sites, is algal and seagrass material, individually or possibly as a mixture, and that mangroves are not the sole source of carbon in these systems.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12754
Subject Headings: Mangrove ecology, Food chains (Ecology)
Format: Document (PDF)

Title: Tropical crustose coralline algal community and individual growth responses to light and elevated pCO2.
Creator: Dutra, Elizabeth A., Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Crustose coralline algae (CCA) are important reef stabilizers and their susceptibility to anthropogenic climate change and ocean acidification (OA) is of concern. Ocean acidification effects on benthic algal communities were determined by the response of CCA, fleshy macroalgae and microalgae to the interaction of pCO2 and light. I examined if elevated pCO2 and light influences CCA dominance by assessing their growth, recruitment and calcification. Elevated pCO2 under natural reef diurnal CO2...
Show moreCrustose coralline algae (CCA) are important reef stabilizers and their susceptibility to anthropogenic climate change and ocean acidification (OA) is of concern. Ocean acidification effects on benthic algal communities were determined by the response of CCA, fleshy macroalgae and microalgae to the interaction of pCO2 and light. I examined if elevated pCO2 and light influences CCA dominance by assessing their growth, recruitment and calcification. Elevated pCO2 under natural reef diurnal CO2 cycles did not significantly affect CCA percent cover, calcification rates or survival of adult CCA lobes. No significant community pCO2 effects were observed, rather light controlled dominance. The percent cover of microalgae increased in highlight, while CCA increased in the shade. My results indicate that algal response to irradiance is a more significant driver of reef benthic algal change than pCO2 levels predicted for 2100; however, this conclusion should be corroborated in longer-term and in field experiments.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004365, http://purl.flvc.org/fau/fd/FA00004365
Subject Headings: Marine algae, Algal communities--Monitoring, Coral reef ecology
Format: Document (PDF)

Coral reef ecology. (2)	+ -
Algal communities--Monitoriing. (1)	+ -
Algal communities--Monitoring (1)	+ -
Aquaculture--Environmental aspects--Florida (1)	+ -
Carbon cycle (Biogeochemistry) (1)	+ -

Chemical oceanography. (1)	+ -
Coastal ecology--Florida (1)	+ -
Coastal zone management (1)	+ -
Coastal zone management--Florida (1)	+ -
Coral reef ecology (1)	+ -
Environmental mapping. (1)	+ -
Estuarine sediments--Florida--Florida Bay (1)	+ -
Food chains (Ecology) (1)	+ -
Halimeda. (1)	+ -
Hydrogen sulfide (1)	+ -
Mangrove ecology (1)	+ -
Marine algae (1)	+ -
Marine algae--Ecophysiology. (1)	+ -
Photobiology. (1)	+ -
Plant physiology. (1)	+ -
Plants--Effect of light on. (1)	+ -
Pore water (1)	+ -
Ruppia maritima -- Ecology -- Everglades National Park (Fla.) (1)	+ -
Ruppia maritima -- Ecology -- Florida Bay (Fla.) (1)	+ -
Seagrasses (1)	+ -
Seagrasses -- Everglades National Park (Fla.) (1)	+ -
Seagrasses -- Florida Bay (Fla.) (1)	+ -
Thalassia testudinum (1)	+ -
Wetland ecology -- Everglades National Park (Fla.) (1)	+ -
Wetland ecology -- Florida Bay (Fla.) (1)	+ -

Charles E. Schmidt College of Science (7)	+ -
Florida Atlantic University (7)	+ -
Dutra, Elizabeth A. (1)	+ -
Kieckbusch, David Keith (1)	+ -
Kletou, Demetris (1)	+ -

MacLeod, Kasey (1)	+ -
Peach, Katherine (1)	+ -
Strazisar, Theresa (1)	+ -
Zweng, Regina C. (1)	+ -

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