A synthesis of long-term research by the Florida Coastal Everglades LTER Program

This paper synthesizes research conducted during the first 5–6 years of the Florida Coastal Everglades Long-Term Ecological Research Program (FCE LTER). My objectives are to review our research to date, and to present a new central theme and conceptual approach for future research. Our research has focused on understanding how dissolved organic matter (DOM) from upstream oligotrophic marshes interacted with a marine source of the limiting nutrient, phosphorus (P), to control productivity in the oligohaline estuarine ecotone. We have been working along freshwater to marine transects in two drainage basins located in Everglades National Park (ENP). The Shark River Slough transect (SRS) has a direct connection to the Gulf of Mexico, providing this estuarine ecotone with a source of marine P. The oligohaline ecotone along our southern Everglades transect (TS/Ph), however, is separated from this marine P source by the Florida Bay estuary. We originally hypothesized an ecosystem productivity peak in the SRS ecotone, driven by the interaction of marine P and Everglades DOM, but no such productivity peak in the TS/Ph ecotone because of this lack of marine P. Our research to date has tended to show the opposite pattern, however, with many ecosystem components showing enhanced productivity in the TS/Ph ecotone, but not in the SRS ecotone. Water column P concentrations followed a similar pattern, with unexpectedly high P in the TS/Ph ecotone during the dry season. Our organic geochemical research has shown that Everglades DOM is more refractory than originally hypothesized. We have also begun to understand the importance of detrital organic matter production and transport to ecotone dynamics and as the base of aquatic food webs. Our future research will build on this substantial body of knowledge about these oligotrophic estuaries. We will direct our efforts more strongly on biophysical dynamics in the oligohaline ecotone regions. Specifically, we will be focusing on inputs to these regions from four primary water sources: freshwater Everglades runoff, net precipitation, marine inputs, and groundwater. We are hypothesizing that dry season groundwater inputs of P will be particularly important to TS/Ph ecotone dynamics because of longer water residence times in this area. Our organic geochemical, biogeochemical, and ecosystem energetics work will focus more strongly on the importance of detrital organics and will take advantage of a key Everglades Restoration project, scheduled for 2008 or 2009, that will increase freshwater inputs to our SRS transect only. Finally, we will also begin to investigate the human dimensions of restoration, and of a growing population in south Florida that will become increasingly dependent on the Everglades for critical ecosystem services (including fresh water) even as its growth presents challenges to Everglades sustainability.

Chemical characteristics of dissolved organic matter in an oligotrophic subtropical wetland/estuarine ecosystem

Fluorescence properties of whole water samples and molecular characteristics of ultrafiltrated dissolved organic matter (UDOM > 1,000 D) such as lignin phenol and neutral sugar compositions and 13C nuclear magnetic resonance (NMR) spectra were determined along a freshwater to marine gradient in Everglades National Park. Furthermore, UDOM samples were categorized by hierarchical cluster analysis based on their pyrolysis gas chromatography/mass spectrometry products. Fluorescence properties suggest that autochthonous DOM leached/exuded from biomass is quantitatively important in this system. 13C NMR spectra showed that UDOM from the oligotrophic Taylor Slough (TS) and Florida Bay (FB) ecosystems has low aromatic C (13% ± 3% for TS; 2% ± 2% for FB) and very high O-alkyl C (54% ± 4% for TS; 75% ± 4% for FB) concentrations. High O-alkyl C concentrations in FB suggest seagrass/phytoplankton communities as dominant sources of UDOM. The amount of neutral sugars was not appreciably different between the TS and FB sites (115 ± 12 mg C g C-1 UDOM) but their concentrations suggest a low level of diagenesis and high production rates of this material in this oligotrophic environment. Total yield of lignin phenols (vanillyl + syringyl phenols) in TS was low (0.20–0.39 mg 100 mg C-1 UDOM) compared with other riverine environments and even lower in FB (0.04–0.07 mg 100 mg C-1 UDOM) and could be a result of photodegradation and/or dilution by other utochthonous DOM. The high O-alkyl and low aromatic nature of this UDOM suggests significant biogenic inputs (as compared with soils) and limited bioavailability in this ecosystem.

Organic Biogeochemistry of Detrital Flocculent Material (Floc) in a Subtropical, Coastal Wetland

Flocculent materials (floc), in aquatic systems usually consist of a non-consolidated layer of biogenic, detrital material relatively rich in organic matter which represents an important food-web component for invertebrates and fish. Thus, variations in its composition could impact food webs and change faunal structure. Transport, remineralization rates and deposition of floc may also be important factors in soil/sediment formation. In spite of its relevance and sensitivity to external factors, few chemical studies have been carried out on the biogeochemistry of floc material. In this study, we focused on the molecular characterization of the flocculent organic matter (OM), the assessment of its origin and its environmental fate at five stations along a freshwater to marine ecotone, namely the Taylor Slough, Everglades National Park (ENP), Florida. To tackle this issue, suspended, unconsolidated, detrital floc samples, soils/sediments and plants were analyzed for bulk properties, biomarkers and pigments. Both geochemical proxies and biomass-specific biomarkers were used to assess OM sources and transformations. Our results show that the detrital organic matter of the flocculent material is largely regulated by local vegetation inputs, ranging from periphyton, emergent and submerged plants and terrestrial plants such as mangroves, with molecular evidence of different degrees of diagenetic reworking, including fungal activity. Evidence is presented for both hydrodynamic transport of floc materials, and incorporation of floc OM into soils/sediments. However, some molecular parameters showed a decoupling between floc and underlying soil/sediment OM, suggesting that physical transport, incorporation and degradation/remineralization of OM in floc may be controlled by a combination of a variety of complex biogeochemical variables including hydrodynamic transport, hydroperiod characteristics, primary productivity, nutrient availability, and OM quality among others. Further investigations are needed to better understand the ecological role of floc in freshwater and coastal wetlands.

Changes in mass and nutrient content of wood during decomposition in a south Florida mangrove forest

1. Large pools of dead wood in mangrove forests following disturbances such as hurricanes may influence nutrient fluxes. We hypothesized that decomposition of wood of mangroves from Florida, USA (Avicennia germinans, Laguncularia racemosa and Rhizophora mangle), and the consequent nutrient dynamics, would depend on species, location in the forest relative to freshwater and marine influences and whether the wood was standing, lying on the sediment surface or buried. 2. Wood disks (8–10 cm diameter, 1 cm thick) from each species were set to decompose at sites along the Shark River, either buried in the sediment, on the soil surface or in the air (above both the soil surface and high tide elevation). 3. A simple exponential model described the decay of wood in the air, and neither species nor site had any effect on the decay coefficient during the first 13 months of decomposition. 4. Over 28 months of decomposition, buried and surface disks decomposed following a two-component model, with labile and refractory components. Avicennia germinans had the largest labile component (18 ± 2% of dry weight), while Laguncularia racemosa had the lowest (10 ± 2%). Labile components decayed at rates of 0.37–23.71% month−1, while refractory components decayed at rates of 0.001–0.033% month−1. Disks decomposing on the soil surface had higher decay rates than buried disks, but both were higher than disks in the air. All species had similar decay rates of the labile and refractory components, but A. germinans exhibited faster overall decay because of a higher proportion of labile components. 5. Nitrogen content generally increased in buried and surface disks, but there was little change in N content of disks in the air over the 2-year study. Between 17% and 68% of total phosphorus in wood leached out during the first 2 months of decomposition, with buried disks having the greater losses, P remaining constant or increasing slightly thereafter. 6. Newly deposited wood from living trees was a short-term source of N for the ecosystem but, by the end of 2 years, had become a net sink. Wood, however, remained a source of P for the ecosystem. 7. As in other forested ecosystems, coarse woody debris can have a significant impact on carbon and nutrient dynamics in mangrove forests. The prevalence of disturbances, such as hurricanes, that can deposit large amounts of wood on the forest floor accentuates the importance of downed wood in these forests.

Concessions in National Parks: Responsible Tourism

Concession operations in natural areas have always been a source of controversy. The objectives of profit and preservation are seen by many to be incompatible. The author will examine the relationship of national park concessions and the environments in which they operate, focusing on concession selection and operation, using responsible tourism concepts as a guide

Novel analytical methodologies for the monitoring of traditional and non-traditional pollutants in different environmental compartments of South Florida

Routine monitoring of environmental pollution demands simplicity and speed without sacrificing sensitivity or accuracy. The development and application of sensitive, fast and easy to implement analytical methodologies for detecting emerging and traditional water and airborne contaminants in South Florida is presented. A novel method was developed for quantification of the herbicide glyphosate based on lyophilization followed by derivatization and simultaneous detection by fluorescence and mass spectrometry. Samples were analyzed from water canals that will hydrate estuarine wetlands of Biscayne National Park, detecting inputs of glyphosate from both aquatic usage and agricultural runoff from farms. A second study describes a set of fast, automated LC-MS/MS protocols for the analysis of dioctyl sulfosuccinate (DOSS) and 2-butoxyethanol, two components of Corexit®. Around 1.8 million gallons of those dispersant formulations were used in the response efforts for the Gulf of Mexico oil spill in 2010. The methods presented here allow the trace-level detection of these compounds in seawater, crude oil and commercial dispersants formulations. In addition, two methodologies were developed for the analysis of well-known pollutants, namely Polycyclic Aromatic Hydrocarbons (PAHs) and airborne particulate matter (APM). PAHs are ubiquitous environmental contaminants and some are potent carcinogens. Traditional GC-MS analysis is labor-intensive and consumes large amounts of toxic solvents. My study provides an alternative automated SPE-LC-APPI-MS/MS analysis with minimal sample preparation and a lower solvent consumption. The system can inject, extract, clean, separate and detect 28 PAHs and 15 families of alkylated PAHs in 28 minutes. The methodology was tested with environmental samples from Miami. Airborne Particulate Matter is a mixture of particles of chemical and biological origin. Assessment of its elemental composition is critical for the protection of sensitive ecosystems and public health. The APM collected from Port Everglades between 2005 and 2010 was analyzed by ICP-MS after acid digestion of filters. The most abundant elements were Fe and Al, followed by Cu, V and Zn. Enrichment factors show that hazardous elements (Cd, Pb, As, Co, Ni and Cr) are introduced by anthropogenic activities. Data suggest that the major sources of APM were an electricity plant, road dust, industrial emissions and marine vessels.

Paleoenvironmental change in wetlands of the Florida Everglades, southeast USA

In this special issue, we report on efforts to reconstruct paleoclimate/paleolimnology of the Florida Everglades, applying a wide range of techniques including sedimentological, micropaleontological and biogeochemical approaches. The papers included here describe results obtained by studies conducted in Everglades National Park and the greater South Florida Everglades by Florida Coastal Everglades Long Term Ecological Research Program (FCE LTER) collaborators. This multi-investigator project contrasts nutrient dynamics in two inland-to-marine transects aligned along separate drainages in southern Florida that differ in their susceptibility to coastal pressures and in volume of freshwater delivery. This effort focuses on the paleoecological aspects of FCE LTER research that address scales of ecosystem transformations driven by climate variability and change and human activities. The central question addressed by this body of work is “How is the shape of the freshwater-to-marine gradient in the Florida coastal Everglades controlled by changes in climate, freshwater inflow (i.e. through human activities), and disturbance (i.e. sea level rise, hurricanes, fire)?”

Relating Freshwater Flow with Estuarine Water Quality in the Southern Everglades Mangrove Ecotone

Florida Bay is more saline than it was historically, and reduced freshwater flows may lead to more phosphorus inputs to the mangrove ecotone from the marine end-member. This is important given plans to restore freshwater flow into eastern Florida Bay. We investigated the relationships between salinity, nutrients, and hydrologic variables in the mangrove ecotone of Taylor Slough. We expected that total phosphorus (TP) would increase with salinity, reflecting a downstream marine source, while total nitrogen (TN) would increase with flow in the mangrove ecotone. Despite expectations of increased flows improving the ecological health of lower Taylor Slough and Florida Bay, total nitrogen (TN) and total phosphorus (TP) dynamics may shift in response to new conditions of flow and salinity as well as organic carbon, N, and P availability. Our results showed that TP concentrations are more discharge-driven while TN is more variable and potentially derived from different sources along the flow path from the freshwater Everglades marshes to Florida Bay. Increased flow of freshwater through Taylor Slough will likely decrease TP concentrations in this historically oligotrophic and P-limited ecosystem. However, more studies along the mangrove ecotone is needed to understand how increased flows will affect nitrogen dynamics relative to phosphorus.

The 2008 Terrestrial Vegetation of Biscayne National Parko FL, USA Derived From Aerial Photography, NDVI, and LiDAR

Established as a National Park in 1980, Biscayne National Park (BISC) comprises an area of nearly 700 km2 , of which most is under water. The terrestrial portions of BISC include a coastal strip on the south Florida mainland and a set of Key Largo limestone barrier islands which parallel the mainland several kilometers offshore and define the eastern rim of Biscayne Bay. The upland vegetation component of BISC is embedded within an extensive coastal wetland network, including an archipelago of 42 mangrove-dominated islands with extensive areas of tropical hardwood forests or hammocks. Several databases and vegetation maps describe these terrestrial communities. However, these sources are, for the most part, outdated, incomplete, incompatible, or/and inaccurate. For example, the current, Welch et al. (1999), vegetation map of BISC is nearly 10 years old and represents the conditions of Biscayne National Park shortly after Hurricane Andrew (August 24, 1992). As a result, a new terrestrial vegetation map was commissioned by The National Park Service Inventory and Monitoring Program South Florida / Caribbean Network.

Effects of vessel traffic on relative abundance and behaviour of cetaceans : the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea

Acknowledgements This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco (CTS) and by the National Park of the Archipelago de La Maddalena. We thank the Natural Reserve of Bocche di Bonifacio for the support provided during data collection. The authors thank the numerous volunteers of the Caprera Dolphin Research Centre and especially Marco Ferraro, Mirko Ugo, Angela Pira and Maurizio Piras whose assistance during field observation and skills as a boat driver were invaluable.

CAST OFF: MARITIME LABOR IN AMERICA FROM 1935 TO 1955

Many studies have observed the precipitous decline in American shipping following the Second World War. Most focus on changes in maritime policy and the upsurge of flags of convenience. Yet this interpretation relegates mariners to a footnote. This thesis argues that America abandoned its seamen years before it abandoned its merchant marine, and that the labor story is an integral and largely overlooked dimension of the industry’s broader decline. It explores how the status and makeup of American seamen underwent monumental shifts from 1935 to 1955. Increased nationalization, improved conditions, and a patriotic cause boosted the standing of the industry, but federal and union intervention also changed the composition of the workforce and even eroded seamen’s status. These greater controls on mariners negatively affected the industry and this work contends that labor played a role in the transformation, and even decline, of the overall American Merchant Marine.

African Burial Ground : African Burial Ground National Monument, New York /

"*GPO:2011--365-615/80593 Reprint 2011."

African Burial Ground : African Burial Ground National Monument, New York /

"*GPO:2012--372-849/80797 Reprint 2011."

Theodore Roosevelt Birthplace National Historic Site, New York /

"*GPO:2010--357-940/80530."

Statue of Liberty National Monument, maps /

In text: In 1986 the Statue will be 100 years old.