Absolute Configuration and Biosynthesis of Pahayokolide A from Lyngbya sp. Strain 15-2 of the Florida Everglades

Pahayokolides A-D are cytotoxic cyclic polypeptides produced by the freshwater cyanobacterium Lyngbya sp. strain 15-2 that possess an unusual β-amino acid, 3-amino-2,5,7,8-tetrahydroxy-10-methylundecanoic acid (Athmu). The absolute configuration of pahayokolides A-D was determined using advanced Marfey’s method. It was also confirmed that a pendant N-acetyl-N-methyl leucine moiety in pahayokolide A was absent in pahayokolides B and pahayokolides C-D were conformers of pahayokolide A. Feeding experiments indicated that the biosynthesis of the Athmu sidechain arises from leucine or α-ketoisovalerate, however could not be further extended by three rounds of condensation with malonate units. Putative four peptide and one unique polyketide synthetases in Lyngbya sp. strain 15-2 were identified by using a PCR method and degenerate primers derived from conserved core sequences of known NRPSs and PKSs. Identification of one unique KS domain conflicted with the logic rule that the long side chain of Athmu was assembled by three rounds of ketide extensions if PKSs were involved. A gene cluster (pah) encoding a peptide synthetase putatively producing pahayokolide was cloned, partially sequenced and characterized. Seven modules of the non-ribosomal peptide synthetase (NRPS) were identified. Ten additional opening reading frames (ORFs) were found, responsible for peptide resistance, transport and degradation. Although the predicted substrate specificities of NRPS agreed with the structure of pahayokolide A partially, the disagreement could be explained. However, no PKS gene was found in the pah gene cluster.

Seed Dispersal and Reproduction Patterns Among Everglades Plants

In this study three aspects of sexual reproduction in Everglades plants were examined to more clearly understand seed dispersal and the allocation of resources to sexual reproduction— spatial dispersal process, temporal dispersal of seeds (seedbank), and germination patterns in the dominant species, sawgrass (Cladium jamaicense). Community assembly rules for fruit dispersal were deduced by analysis of functional traits associated with this process. Seedbank ecology was investigated by monitoring emergence of germinants from sawgrass soil samples held under varying water depths to determine the fate of dispersed seeds. Fine-scale study of sawgrass fruits yielded information on contributions to variation in sexually produced propagules in this species, which primarily reproduces vegetatively. It was hypothesized that Everglades plants possess a set of functional traits that enhance diaspore dispersal. To test this, 14 traits were evaluated among 51 species by factor analysis. The factorial plot of this analysis generated groups of related traits, with four suites of traits forming dispersal syndromes. Hydrochory traits were categorized by buoyancy and appendages enhancing buoyancy. Anemochory traits were categorized by diaspore size and appendages enhancing air movement. Epizoochory traits were categorized by diaspore size, buoyancy, and appendages allowing for attachment. Endozoochory traits were categorized by diaspore size, buoyancy, and appendages aiding diaspore presentation. These patterns/trends of functional trait organization also represent dispersal community assembly rules. Seeds dispersed by hydrochory were hypothesized to be caught most often in the edge of the north side of sawgrass patches. Patterns of germination and dispersal mode of all hydrochorous macrophytes with propagules in the seedbank were elucidated by germination analysis from 90 soil samples collected from 10 sawgrass patches. Mean site seed density was 486 seeds/m2 from 13 species. Most seeds collected at the north side of patches and significantly in the outer one meter of the patch edge (p = 0.013). Sawgrass seed germination was hypothesized to vary by site, among individual plants, and within different locations of a plant’s infructescence. An analysis of sawgrass fruits with nested ANOVAs found that collection site and interaction of site x individual plant significantly affect germination ability, seed viability, and fruit size (p < 0.050). Fruit location within a plant’s infructescence did not significantly affect germination. As for allocation of resources to sexual reproduction, only 17.9% of sawgrass seeds germinated and only 4.8% of ungerminated seeds with fleshy endosperm were presumed viable, but dormant. Collectively, only 22% of all sawgrass seeds produced were viable.

The rodent fauna of Long Pine Key, Everglades National Park: a comparison of habitat types

Rodents are often involved at several stages of trophic dynamics. Consequently they often play crucial roles in the structure and function of many complex ecological systems. This study sought to address the lack of baseline data concerning rodents in tropical areas, and south Florida in particular. Live trapping took place in the four major habitat types of the Long Pine Key area of Everglades National Park over the course of one year. I compared population structures and abundance of murid rodents in the four habitat types, and tested multiple weather variables for their effectiveness as predictors of rodent abundance. I found the Long Pine Key area to be depauperate in terms of species diversity. Each of the four species of rodent encountered favored a particular habitat type. The density of the understory vegetation and the avoidance of avian predators in particular appear to be the most important factors in the distribution and abundance of rodents in the Long Pine Key area of Everglades National Park.

Detecting Calcareous Periphyton Mats in the Greater Everglades Using Passive Remote Sensing Methods

Use of remotely sensed data for environmental and ecological assessment has recently become more widespread in wetland research and management and advantages and limitations of this approach have been addresses (Ozesmi and Bauer 2002). Applications of remote sensing (RS) methods vary in spatial and temporal extent and resolution, in the types of data acquired, and in digital processing and pattern recognition algorithms used.

Seasonal activity and road mortality of the snakes of the Pa-Hay-Okee wetlands of Everglades National Park

The current study describes the composition and activity of the snake community of the Pa-hay-okee wetlands of Everglades National Park. The study was conducted from January 1987 to January 1989. Sixteen species were observed, with Thamnophis sauritus, Thamnophis sirtalis, Nerodia fasciata pictiventris, and Agkistrodon piscivorus representing 90.2% of the total sample. The seasonal distribution and activity of the snakes were closely related to fluctuations in the water table. Most activity occurred in the winter months as snakes migrated west following the drying water edge of Shark River Slough. Seventy percent of all snakes observed during this study were either injured or dead on the road. Over 50% of annual mortality occurred during migration. The impact that road mortality is having on the local snake community cannot be ignored. Management options are provided to minimize loss. A comparison is made to the snake community of the Long Pine Key Region of Everglades National Park.

The Use of Hyphenated Spectrometric Techniques for the Environmental Forensic Assessment of Non-Traditional Pollutants and Degradates in the Greater Florida Everglades

A comprehensive investigation of sensitive ecosystems in South Florida with the main goal of determining the identity, spatial distribution, and sources of both organic biocides and trace elements in different environmental compartments is reported. This study presents the development and validation of a fractionation and isolation method of twelve polar acidic herbicides commonly applied in the vicinity of the study areas, including e.g. 2,4-D, MCPA, dichlorprop, mecroprop, picloram in surface water. Solid phase extraction (SPE) was used to isolate the analytes from abiotic matrices containing large amounts of dissolved organic material. Atmospheric-pressure ionization (API) with electrospray ionization in negative mode (ESP-) in a Quadrupole Ion Trap mass spectrometer was used to perform the characterization of the herbicides of interest. The application of Laser Ablation-ICP-MS methodology in the analysis of soils and sediments is reported in this study. The analytical performance of the method was evaluated on certified standards and real soil and sediment samples. Residential soils were analyzed to evaluate feasibility of using the powerful technique as a routine and rapid method to monitor potential contaminated sites. Forty eight sediments were also collected from semi pristine areas in South Florida to conduct screening of baseline levels of bioavailable elements in support of risk evaluation. The LA-ICP-MS data were used to perform a statistical evaluation of the elemental composition as a tool for environmental forensics. A LA-ICP-MS protocol was also developed and optimized for the elemental analysis of a wide range of elements in polymeric filters containing atmospheric dust. A quantitative strategy based on internal and external standards allowed for a rapid determination of airborne trace elements in filters containing both contemporary African dust and local dust emissions. These distributions were used to qualitative and quantitative assess differences of composition and to establish provenance and fluxes to protected regional ecosystems such as coral reefs and national parks.

Exploring the Use of Everglades Agricultural Area Canal Water as Base Medium for the Mass Production of Algae for Biofuels

Freshwater use is a major concern in the mass production of algae for biofuels. This project examined the use of canal water obtained from the Everglades Agricultural Area as a base medium for the mass production of algae. This water is not suitable for human consumption, and it is currently used for crop irrigation. A variety of canals were found to be suitable for water collection. Comparison of two methods for algal production showed no significant difference in biomass accumulation. It was discovered that synthetic reticulated foam can be used for algal biomass collection and harvest, and there is potential for its application in large-scale operations. Finally, it was determined that high alkaline conditions may help limit contaminants and competing organisms in growing algae cultures.

Everglades anglers

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Using Stable Isotopes to Investigate Trophic Interactions of Bottlenose Dolphins (Tursiops truncatus) in the Coastal Everglades

Top predators are best known for their ability to affect their communities through inflicting mortality on prey and inducing behavioral modifications (e.g. risk effects). Recent scientific evidence suggests that predators may have additional roles in bottom-up processes such as transporting materials within and across habitat boundaries. The Florida Coastal Everglades (FCE) is an “upside-down” oligotrophic estuary where productivity decreases from the mouth of the estuary to freshwater marshes. Research in the FCE suggest that predators can act as mobile links between disparate habitats and can potentially affect nutrient and biogeochemical dynamics through localized behaviors (e.g. American alligators and juvenile bull sharks). To date, little is known about bottlenose dolphins (Tursiops truncatus) in the FCE beyond broad-scale patterns of abundance. Because they are highly mobile mammals commonly found in coastal waters, bottlenose dolphins are an interesting case study for investigating the influence of ecology on the evolution of local adaptations. Within this influence lies the potential for investigation of the related roles those adaptations play in coastal ecosystems due to their high metabolic rates, movement capabilities, and tendency to display specialized foraging behaviors. Stable isotope analysis of biopsy samples were used to investigate habitat use, trophic interactions, and patterns of individual specialization in bottlenose dolphins to gain functional insights into ecosystem dynamics. δ13 C isotopic values are used to differentiate the relative importance of a food web to the diet of an organism, while δ15 N values are used to evaluate the relative trophic position of an organism. Dolphin δ13 C isotopic values seem to suggest that dolphins are foraging within single ecosystems and may not be moving nutrients across ecosystem boundaries while their δ15 N isotopic values appear to be of a top predator, at a similar level to bull sharks and alligators in FCE. Further research is necessary to provide vital insight into the large predators’ role in affecting the evolution of local adaptations. Conducting this research should also provide information for predicting how future changes occurring due to restoration dynamics (see CERP: evergladesplan.org) and climate change will affect the ecological roles of these animals.

Using Stable Isotopes to Investigate Trophic Interactions of Bottlenose Dolphins (Tursiops truncatus) in the Coastal Everglades”

Top predators are best known for their ability to affect their communities through inflicting mortality on prey and inducing behavioral modifications (e.g. risk effects). Recent scientific evidence suggests that predators may have additional roles in bottom-up processes such as transporting materials within and across habitat boundaries. The Florida Coastal Everglades (FCE) is an “upside-down” oligotrophic estuary where productivity decreases from the mouth of the estuary to freshwater marshes. Research in the FCE suggest that predators can act as mobile links between disparate habitats and can potentially affect nutrient and biogeochemical dynamics through localized behaviors (e.g. American alligators and juvenile bull sharks). To date, little is known about bottlenose dolphins (Tursiops truncatus) in the FCE beyond broad-scale patterns of abundance. Because they are highly mobile mammals commonly found in coastal waters, bottlenose dolphins are an interesting case study for investigating the influence of ecology on the evolution of local adaptations. Within this influence lies the potential for investigation of the related roles those adaptations play in coastal ecosystems due to their high metabolic rates, movement capabilities, and tendency to display specialized foraging behaviors. Stable isotope analysis of biopsy samples were used to investigate habitat use, trophic interactions, and patterns of individual specialization in bottlenose dolphins to gain functional insights into ecosystem dynamics. δ13 C isotopic values are used to differentiate the relative importance of a food web to the diet of an organism, while δ15 N values are used to evaluate the relative trophic position of an organism. Dolphin δ13 C isotopic values seem to suggest that dolphins are foraging within single ecosystems and may not be moving nutrients across ecosystem boundaries while their δ15 N isotopic values appear to be of a top predator, at a similar level to bull sharks and alligators in FCE. Further research is necessary to provide vital insight into the large predators’ role in affecting the evolution of local adaptations. Conducting this research should also provide information for predicting how future changes occurring due to restoration dynamics (see CERP: evergladesplan.org) and climate change will affect the ecological roles of these animals.