Physical Sciences and Mathematics Commons^™

Environmental Factors Controlling The Distributions Of Botryococcus Braunii (A, B And L) Biomarkers In A Subtropical Freshwater Wetland, Ding He, Bernd R.T. Simoneit, Rudolf Jaffe

FCE LTER Journal Articles

Here we report the molecular biomarker co-occurrence of three different races of Botryococcus braunii (B. braunii) in the freshwater wetland ecosystem of the Florida Everglades, USA. Thespecific biomarkers include C32–C34 botryococcenes for race B, C27–C32 n-alkadienes and n-alkatrienes for race A, and lycopadiene for race L. The n-alkadienes and n-alkatrienes were present up to 3.1 and 69.5 µg/g dry weight (dw), while lycopadiene was detected in lower amounts up to 3.0 and 1.5 µg/g dw in periphyton and floc samples, respectively. Nutrient concentrations (P and N) did not significantly correlate with the abundances of …

Homogenization Of Plant Diversity, Composition, And Structure In North American Urban Yards, William D. Pearse, Jeannine Cavender-Bares, Sarah E. Hobbie, Meghan L. Avolio, Neil Bettez, Rinku Roy Chowdhury, Lindsay E. Darling, Peter M. Groffman, J. Morgan Grove, Sharon J. Hall, James B. Heffernan, Jennifer Learned, Christopher Neill, Kristen C. Nelson, Diane E. Pataki, Benjamin L. Ruddell, Meredith K. Steele, Tara L.E. Trammell

FCE LTER Journal Articles

Urban ecosystems are widely hypothesized to be more ecologically homogeneous than natural ecosystems. We argue that urban plant communities assemble from a complex mix of horticultural and regional species pools, and evaluate the homogenization hypothesis by comparing cultivated and spontaneously occurring urban vegetation to natural area vegetation across seven major U.S. cities. There was limited support for homogenization of urban diversity, as the cultivated and spontaneous yard flora had greater numbers of species than natural areas, and cultivated phylogenetic diversity was also greater. However, urban yards showed evidence of homogenization of compositionand structure. Yards were compositionally more …

Biotime: A Database Of Biodiversity Time Series For The Anthropocene, Maria Dornelas, Laura H. Antao, Faye Moyes, Amanda E. Bates, William A. Gould, L. Donald, Edward Castaneda-Moya

FCE LTER Journal Articles

No abstract provided.

Remote Sensing Of Seasonal Changes And Disturbances In Mangrove Forest: A Case Study From South Florida, Keqi Zhang, Bina Thapa, Michael S. Ross, Daniel Gann

FCE LTER Journal Articles

Knowledge of the spatial and temporal changes caused by episodic disturbances and seasonal variability is essential for understanding the dynamics of mangrove forests at the landscape scale, and for building a baseline that allows detection of the effects of future environmental change. In combination with LiDAR data, we calculated four vegetation indices from 150 Landsat TM images from 1985 to 2011 in order to detect seasonal changes and distinguish them from disturbances due to hurricanes and chilling events in a mangrove-dominated coastal landscape. We found that normalized difference moisture index (NDMI) performed best in identifying both seasonal and event-driven episodic …

Global Parameterization And Validation Of A Two-Leaf Light Use Efficiency Model For Predicting Gross Primary Production Across Fluxnet Sites, Yanlian Zhou, Xiaocui Wu, Weimin Ju, Jing M. Chen, Shaoqiang Wang, Huimin Wang, Wenping Yuan, T. Andrew Black, Rachhpal Jassal, Andreas Ibrom, Shijie Han, Junhua Yan, Hank Margolis, Olivier Roupsard, Yingnian Li, Fenghua Zhao, Gerard Kiely, Gregory Starr, Marian Pavelka, Leonardo Montagnani, Georg Wohlfahrt, Petra D'Odorico, David Cook, M. Altaf Arain, Damien Bonal, Jason Beringer, Peter D. Blanken, Benjamin Loubet, Monique Y. Leclerc, Giorgio Matteucci, Zoltan Nagy, Janusz Olejnik, Kyaw Tha Paw U, Andrej Varlagin

FCE LTER Journal Articles

Light use efficiency (LUE) models are widely used to simulate gross primary production (GPP). However, the treatment of the plant canopy as a big leaf by these models can introduce large uncertainties in simulated GPP. Recently, a two-leaf light use efficiency (TL-LUE) model was developed to simulate GPP separately for sunlit and shaded leaves and has been shown to outperform the big-leaf MOD17 model at six FLUX sites in China. In this study we investigated the performance of the TL-LUE model for a wider range of biomes. For this we optimized the parameters and tested the TL-LUE model using data …

Associations Between The Molecular And Optical Properties Of Dissolved Organic Matter In The Florida Everglades, A Model Coastal Wetland System, Sasha Wagner, Rudolf Jaffe´, Kaelin Cawley, Thorston Dittmar, Aron Stubbins

FCE LTER Journal Articles

Optical properties are easy-to-measure proxies for dissolved organic matter (DOM) composition, source, and reactivity. However, the molecular signature of DOM associated with such optical parameters remains poorly defined. The Florida coastal Everglades is a subtropical wetland with diverse vegetation (e.g., sawgrass prairies, mangrove forests, seagrass meadows) and DOM sources (e.g., terrestrial, microbial, and marine). As such, the Everglades is an excellent model system from which to draw samples of diverse origin and composition to allow classically-defined optical properties to be linked to molecular properties of the DOM pool. We characterized a suite of seasonally- and spatially-collected DOM samples using optical …

Ecosystem Resistance In The Face Of Climate Change: A Case Study From The Freshwater Marshes Of The Florida Everglades, Sparkle L. Malone, Cynthia Keough, Christina L. Staughammer, Michael G. Ryan, William J. Parton, Paulo Olivas, Steve F. Oberbauer, Jessica Schedlbauer, Gregory Starr

FCE LTER Journal Articles

Shaped by the hydrology of the Kissimmee-Okeechobee-Everglades watershed, the Florida Everglades is composed of a conglomerate of wetland ecosystems that have varying capacities to sequester and store carbon. Hydrology, which is a product of the region’s precipitation and temperature patterns combined with water management policy, drives community composition and productivity. As shifts in both precipitation and air temperature are expected over the next 100 years as a consequence of climate change, CO2 dynamics in the greater Everglades are expected to change. To reduce uncertainties associated with climate change and to explore how projected changes in atmospheric CO2 concentration and climate …

Factors Affecting Individual Foraging Specialization And Temporal Diet Stability Across The Range Of A Large “Generalist” Apex Predator, Adam E. Rosenblatt, James C. Nifong, Michael R. Heithaus, Frank J. Mazzotti, Michael S. Cherkiss, Brian M. Jeffery, Ruth M. Elsey, Rachel A. Decker, Brian R. Silliman, Louis J. Guillette Jr., Russell H. Lowers, Justin C. Larson

FCE LTER Journal Articles

Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable …

El Niño Southern Oscillation (Enso) Enhances Co2 Exchange Rates In Freshwater Marsh Ecosystems In The Florida Everglades, Sparkle L. Malone, Christina L. Staudhammer, Steve F. Oberbauer, Paulo Olivas, Michael G. Ryan, Jessice L. Schedlbauer, Henry W. Loescher, Gregory Starr

FCE LTER Journal Articles

This research examines the relationships between El Niño Southern Oscillation (ENSO), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009–2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in …

Applying Downscaled Global Climate Model Data To A Hydrodynamic Surface-Water And Groundwater Model, Eric Swain, Lydia Stefanova, Thomas Smith

FCE LTER Journal Articles

Precipitation data from Global Climate Models have been downscaled to smaller regions. Adapting this downscaled precipitation data to a coupled hydrodynamic surface-water/groundwater model of southern Florida allows an examination of future conditions and their effect on groundwater levels, inundation patterns, surface-water stage and flows, and salinity. The downscaled rainfall data include the 1996-2001 time series from the European Center for MediumRange Weather Forecasting ERA-40 simulation and both the 1996-1999 and 2038-2057 time series from two global climate models: the Community Climate System Model (CCSM) and the Geophysical Fluid Dynamic Laboratory (GFDL). Synthesized surface-water inflow datasets were developed for the 2038-2057 …

Genetic Evidence For Multiple Sources Of The Non-Native Fish Cichlasoma Urophthalmus (Günther; Mayan Cichlids) In Southern Florida, Elizabeth Harrison, Joel C. Trexler, Timothy M. Collins, Ella Vazquez-Domínguez, Ulises Razo-Mendivil, Wilfredo A. Maramoros, Christian Barrientos

FCE LTER Journal Articles

The number and diversity of source populations may influence the genetic diversity of newly introduced populations and affect the likelihood of their establishment and spread. We used the cytochrome b mitochondrial gene and nuclear microsatellite loci to identify the sources of a successful invader in southern Florida, USA, Cichlasoma urophthalmus (Mayan cichlid). Our cytochrome b data supported an introduction from Guatemala, while our microsatellite data suggested movement of Mayan Cichlids from the upper Yucatán Peninsula to Guatemala and introductions from Guatemala and Belize to Florida. The mismatch between mitochondrial and nuclear genomes suggests admixture of a female lineage from Guatemala, …

The Relationship Between Water Level, Prey Availability And Reproductive Success In Roseate Spoonbills Foraging In A Seasonally-Flooded Wetland While Nesting In Florida Bay, Jerome J. Lorenz

FCE LTER Journal Articles

The coastal wetlands of northeastern Florida Bay are seasonally-inundated dwarf mangrove habitat and serve as a primary foraging ground for wading birds nesting in Florida Bay. A common paradigm in pulse-inundated wetlands is that prey base fishes increase in abundance while the wetland is flooded and then become highly concentrated in deeper water refuges as water levels recede, becoming highly available to wading birds whose nesting success depends on these concentrations. Although widely accepted, the relationship between water levels, prey availability and nesting success has rarely been quantified. I examine this paradigm using Roseate Spoonbills that nest on the islands …

Effect Of Water Management On Interannual Variation In Bulk Soil Properties From The Eastern Coastal Everglades, R. M. Chambers, R. L. Hatch, T. M. Russell

FCE LTER Journal Articles

We examined interannual variation in soil properties from wetlands occurring in adjacent drainage basins from the southeastern Everglades. Triplicate 10-cm soil cores were collected, homogenized, and analyzed during the wet season 2006–2010 from five freshwater sawgrass wetland marshes and three estuarine mangrove forests. Soil bulk density from the Taylor Slough basin ranged from 0.15 gm-cm⁻³ to 0.5 gm-cm⁻³, was higher than from the Panhandle basin every year, and generally increased throughout the study period. Organic matter as a percent loss on ignition ranged from 7 % to 12 % from freshwater marshes and from 13 % to …

A Review Of The Effects Of Altered Hydrology And Salinity On Vertebrate Fauna And Their Habitats In Northeastern Florida Bay, Jerome J. Lorenz

FCE LTER Journal Articles

Estuarine productivity is highly dependent on the freshwater sources of the estuary. In Florida Bay, Taylor Slough was historically the main source of fresh water. Beginning in about 1960, and culminating with the completion of the South Dade Conveyance System in 1984, water management practice began to change the quantity and distribution of flow from Taylor Slough into Northeastern Florida Bay. These practices altered salinity and hydrologic parameters that had measurable negative impacts on vertebrate fauna and their habitats. Here, I review those impacts from published and unpublished literature and anecdotal observations. Almost all vertebrates covered in this review have …

Timescales For Detecting A Significant Acceleration In Sea Level Rise, Ivan D. Haigh, Thomas Wahl, Eelco J. Rohling, René M. Price, Charitha B. Pattiaratchi, Francisco M. Calafat, Sönke Dangendorf

FCE LTER Journal Articles

There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that …

Seasonal Evapotranspiration Patterns In Mangrove Forests, Jordan G. Barr, Marcia S. Delonge, Jose D. Fuentes

FCE LTER Journal Articles

Diurnal and seasonal controls on water vapor fluxes were investigated in a subtropical mangrove forest in Everglades National Park, Florida. Energy partitioning between sensible and latent heat fluxes was highly variable during the 2004–2005 study period. During the dry season, the mangrove forest behaved akin to a semiarid ecosystem as most of the available energy was partitioned into sensible heat, which gave Bowen ratio values exceeding 1.0 and minimum latent heat fluxes of 5 MJ d1. In contrast, during the wet season the mangrove forest acted as a well-watered, broadleaved deciduous forest, with Bowen ratio values of 0.25 and latent …

Photochemical And Microbial Alteration Of Dissolved Organic Matter In Temperate Headwater Streams Associated With Different Land Use, Yuehan Lu, James E. Bauer, Elizabeth A. Canuel, Youhei Yamashita, R. M. Chambers, Rudolf Jaffe´

FCE LTER Journal Articles

[1] Photochemical and microbial transformations of DOM were evaluated in headwater streams draining forested and human-modified lands (pasture, cropland, and urban development) by laboratory incubations. Changes in DOC concentrations, DOC isotopic signatures, and DOM fluorescence properties were measured to assess the amounts, sources, ages, and properties of reactive and refractory DOM under the influence of photochemistry and/or bacteria. DOC in streams draining forest-dominated watersheds was more photoreactive than in streams draining mostly human-modified watersheds, possibly due to greater contributions of terrestrial plant-derived DOC and lower amounts of prior light exposure in forested streams. Overall, the percentage of photoreactive DOC in …

Modeling Light Use Efficiency In A Subtropical Mangrove Forest Equipped With Co2 Eddy Covariance °C, Jordan G. Barr

FCE LTER Journal Articles

Despite the importance of mangrove ecosystems in the global carbon budget, the relationships between environmental drivers and carbon dynamics in these forests remain poorly understood. This limited understanding is partly a result of the challenges associated with in situ flux studies. Tower-based CO₂ eddy covariance (EC) systems are installed in only a few mangrove forests worldwide, and the longest EC record from the Florida Everglades contains less than 9 years of observations. A primary goal of the present study was to develop a methodology to estimate canopy-scale photosynthetic light use efficiency in this forest. These tower-based observations represent a …

A 2,500-Year Record Of Environmental Change In Highlands Hammock State Park (Central Florida, U.S.A.) Inferred From Siliceous Microfossils, Christof Pearce, Holger Cremer, Emmy Lammertsma, Friederike Wagner-Cremer

FCE LTER Journal Articles

Analysis of siliceous microfossils of a 79 cm long peat sediment core from Highlands Hammock State Park, Florida, revealed distinct changes in the local hydrology during the past 2,500 years. The coring site is a seasonally inundated forest where water availability is directly influenced by precipitation. Diatoms, chrysophyte statospores, sponge remains and phytoliths were counted in 25 samples throughout the core. Based on the relative abundance of diatom species, the record was subdivided into four diatom assemblage zones, which mainly reflect the hydrological state of the study site. An age-depth relationship based on radiocarbon measurements of eight samples reveals a …

Summertime Influences Of Tidal Energy Advection On The Surface Energy Balance In A Mangrove Forest, Jordan G. Barr, J. D. Fuentes, M. S. Delonge, T. L. O'Halloran, J. C. Zeiman

FCE LTER Journal Articles

Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in …

Mechanisms Of Bicarbonate Use Influence The Photosynthetic Carbon Dioxide Sensitivity Of Tropical Seagrasses, Justin E. Campbell, James W. Fourqurean

FCE LTER Journal Articles

The photosynthetic bicarbonate () use properties of three widely distributed tropical seagrasses were compared using a series of laboratory experiments. Photosynthetic rates of Thalassia testudinum, Halodule wrightii, and Syringodium filiforme were monitored in an enclosed chamber while being subjected to shifts in pH and dissolved inorganic carbon. Specific mechanisms of seagrass use were compared by examining the photosynthetic effects of the carbonic anhydrase inhibitor acetazolamide (AZ). All seagrasses increased photosynthetic rates with reduced pH, suggesting a large effect of dissolved aqueous carbon dioxide (CO_2(aq)). However, there was considerable interspecific variation in pH response. T. testudinum was …

Controls On Ecosystem Carbon Dioxide Exchange In Short- And Long-Hydroperiod Florida Everglades Freshwater Marshes, Jessica L. Schedlbauer, Jay W. Munyon, Steven F. Oberbauer, Evelyn E. Gaiser, Gregory Starr

FCE LTER Journal Articles

Although freshwater wetlands are among the most productive ecosystems on Earth, little is known of carbon dioxide (CO₂) exchange in low latitude wetlands. The Everglades is an extensive, oligotrophic wetland in south Florida characterized by short- and long-hydroperiod marshes. Chamber-based CO₂ exchange measurements were made to compare the marshes and examine the roles of primary producers, seasonality, and environmental drivers in determining exchange rates. Low rates of CO₂ exchange were observed in both marshes with net ecosystem production reaching maxima of 3.77 and 4.28 μmol CO₂ m⁻² s⁻¹ in short- and long-hydroperiod marshes, …

Controls On Sensible Heat And Latent Energy Fluxes From A Short-Hydroperiod Florida Everglades Marsh, Jessica L. Schedlbauer, Steven F. Oberbauer, Gregory Starr, Kristine L. Jimenez

FCE LTER Journal Articles

Little is known of energy balance in low latitude wetlands where there is a year-round growing season and a climate best defined by wet and dry seasons. The Florida Everglades is a highly managed and extensive subtropical wetland that exerts a substantial influence on the hydrology and climate of the south Florida region. However, the effects of seasonality and active water management on energy balance in the Everglades ecosystem are poorly understood. An eddy covariance and micrometeorological tower was established in a short-hydroperiod Everglades marsh to examine the dominant environmental controls on sensible heat (H) and latent energy …

Survival And Growth Responses Of Eight Everglades Tree Species Along An Experimental Hydrological Gradient On Two Tree Island Types, Susana L. Stoffella, Michael S. Ross, Jay P. Sah, René M. Price, Pamela L. Sullivan, Eric A. Cline, Leonard J. Scinto

FCE LTER Journal Articles

Questions: How are the early survival and growth of seedlings of Everglades tree species planted in an experimental setting on artificial tree islands affected by hydrology and substrate type? What are the implications of these responses for broader tree island restoration efforts?

Location: Loxahatchee Impoundment Landscape Assessment (LILA), Boynton Beach, Florida, USA.

Methods: An experiment was designed to test hydrological and substrate effects on seedling growth and survivorship. Two islands – a peat and a limestone-core island representing two major types found in the Everglades – were constructed in four macrocosms. A mixture of eight tree species was planted on …

Flux Of Organic Carbon In A Riverine Mangrove Wetland In The Florida Coastal Everglades, Melissa M. Romigh, Stephen E. Davis Iii, Victor H. Rivera-Monroy, Robert R. Twilley

FCE LTER Journal Articles

Short-term (daily) and seasonal variations in concentration and flux of dissolved organic carbon (DOC) were examined over 15 tidal cycles in a riverine mangrove wetland along Shark River, Florida in 2003. Due to the influence of seasonal rainfall and wind patterns on Shark River’s hydrology, samplings were made to include wet, dry and transitional (Norte) seasons. We used a flume extending from a tidal creek to a basin forest to measure vertical (vegetated soil/water column) and horizontal (mangrove forest/tidal creek) flux of DOC. We found significant (p < 0.05) variations in surface water temperature, salinity, conductivity, pH and mean concentration of DOC with season. Water temperature and salinity followed seasonal patterns of air temperature and rainfall, while mean DOC concentration was highest during the dry season (May), followed by the wet (October) and ‘Norte’ (December) seasons. This pattern of DOC concentration may be due to a combination of litter production and inundation pattern of the wetland. In contrast to daily (between tides) variation in DOC flux between the mangrove forest and tidal creek, daily variations of mean water quality were not significant. However, within-tide variation of DOC flux, dissolved oxygen content and salinity was observed. This indicated that the length of inundation and water source (freshwater vs. saltwater) variation across tidal cycles influenced water quality and DOC flux in the water column. Net DOC export was measured in October and December, suggesting the mangrove forest was a source of DOC to the adjacent tidal creek during these periods. Net annual export of DOC from the fringe mangrove to both the tidal creek and basin mangrove forest was 56 g C m⁻² year⁻¹. The seasonal pattern in our flux results indicates …

Origin Of Salinity Variations In Florida Bay, P. K. Swart, René M. Price

FCE LTER Journal Articles

This note presents a method of distinguishing the source of freshwater that causes reductions in salinity in the coastal environment of South Florida. This technique, which uses the ¹⁸O and D of the water, allows for differentiation of the freshwater derived from precipitation as opposed to runoff, because surface waters in the Everglades have been highly evaporated and therefore have elevated ¹⁸O and dD values relative to precipitation. A time series of monthly ¹⁸O and D values of surface waters, collected from stations in Florida Bay between 1993 and 1999, has shown that, during this time, the …