Peat Soils of the Everglades of Florida, USA

In this chapter, we briefly discuss the development of the Everglades over the past 5 million years, the modifications made to the Everglades over the past century and a half and the quantification of the changes that have occurred to the peat soils of the Everglades due to natural and anthropogenic causes during this most recent period. Using Geographic Information Systems and historical data sets, we have been able to calculate the original peat volumes, the remaining peat volumes and thus, the amount lost over the past approximately 150 years. From these volume calculations and peat physical and chemical characterizations by the USEPA over a large area of the Everglades, we have estimated the mass of peat and carbon lost, 900 million metric tons and 300 million metric tons, respectively. The amount of peat lost has implications for hydrological, ecological and landscape restoration and habitat recovery for the Everglades

Understanding drivers of aquatic ecosystem metabolism in freshwater subtropical ridge and slough wetlands

How climate and habitat drive variation in aquatic metabolism in wetlands remains uncertain. To quantify differences in seasonal aquatic metabolism among wetlands, we estimated aquatic ecosystem metabolism (gross primary productivity, GPP; ecosystem respiration, ER; net aquatic productivity, NAP) in subtropical ridge and slough wetlands of the Florida Everglades from more than 2 yr of continuously measured water column dissolved oxygen, photosynthetically active radiation (PAR), water temperature, and water depth. Gross primary productivity and ER were modeled from light, temperature, and water depth using non-linear minimization and maximum likelihood. Reaeration rates were estimated from wind speed. Dissolved oxygen was below saturation at all sites during both wet and dry seasons. Water depth interacted with vegetation to influence PAR, water temperature, and spatiotemporal patterns in aquatic metabolism. Gross primary productivity and ER were highest at the slough with lowest submerged aquatic vegetation (low-SAV slough), intermediate in the sawgrass (Cladium jamaicense) ridge site, and lowest at the slough with highest submerged aquatic vegetation (high-SAV slough). Ecosystem respiration was strongly positively correlated with GPP at the sawgrass ridge and low-SAV slough sites. Gross primary productivity increased with water temperature and PAR across all habitat types, whereas ER decreased (more respiration) with water temperature and PAR. Net aquatic productivity was negatively correlated with water temperature and positively correlated with PAR, suggesting that ER was more sensitive than GPP to water temperature. Aquatic metabolism was largely net heterotrophic in all wetlands, and high-SAV appeared to buffer seasonal variation in PAR and water temperatures that drive NAP in subtropical wetlands. Our results suggest that aquatic ecosystem metabolism in wetlands with seasonal hydrology is sensitive to changes in water depth and vegetation density that influence temperature and light. Expanding our understanding of how metabolic processes and carbon cycling in wetland ecosystems vary across gradients in hydrology, vegetation, and organic matter could enhance our understanding and protection of conditions that maximize carbon storage

Transcriptional control of microglia phenotypes in health and disease

Microglia are the main resident macrophage population of the CNS and perform numerous functions required for CNS development, homeostasis, immunity, and repair. Many lines of evidence also indicate that dysregulation of microglia contributes to the pathogenesis of neurodegenerative and behavioral diseases. These observations provide a compelling argument to more clearly define the mechanisms that control microglia identity and function in health and disease. In this Review, we present a conceptual framework for how different classes of transcription factors interact to select and activate regulatory elements that control microglia development and their responses to internal and external signals. We then describe functions of specific transcription factors in normal and pathological contexts and conclude with a consideration of open questions to be addressed in the future

Ph.D. graduate student, Shelby Servais and REU, Julio Pachon conducted collaborative research in the wetland mesocosms during summer 2013.

https://digitalcommons.fiu.edu/fce_lter_photos/1335/thumbnail.jp

Form Fabric Detail

Form Fabric Detail is an architectural study of the Reid Building designed by Steven Holl architects. Through the medium of drawings, photographs and invited essays, it explores the tectonic and the ethereal qualities of an extraordinary building- 'the container' as well as 'the contained'

Recent and Historic Drivers of Landscape Change in the Everglades Ridge, Slough, and Tree Island Mosaic

More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the hydrologic system. Restoration of the patterned landscape structure is one of the primary objectives of the Everglades restoration effort. Recent research has revealed that three main drivers regulated feedbacks that initiated and maintained landscape structure: the spatial and temporal distribution of surface water depths, surface and subsurface flow, and phosphorus supply. Causes of recent degradation include but are not limited to perturbations to these historically important controls; shifts in mineral and sulfate supply may have also contributed to degradation. Restoring predrainage hydrologic conditions will likely preserve remaining landscape pattern structure, provided a sufficient supply of surface water with low nutrient and low total dissolved solids content exists to maintain a rainfall-driven water chemistry. However, because of hysteresis in landscape evolution trajectories, restoration of areas with a fully degraded landscape could require additional human intervention

Efficient delivery and regulable expression of hepatitis C virus full-length and minigenome constructs in hepatocyte-derived cell lines using baculovirus vectors

Baculovirus vectors have been used as efficient delivery vehicles for constitutive gene expression in a variety of mammalian cells. We have further developed the system to allow for regulable expression by placing the gene of interest under the control of an inducible promoter, and complementing it with a second baculovirus vector providing the control elements necessary for promoter activity. We have used this system to express (a) the lacZ gene, (b) a ‘minigenome’ derived from hepatitis C virus (HCV) and carrying lacZ or (c) the full-length HCV viral genome, in human hepatocyte cell lines in an inducible fashion. Control systems that rely on either the absence of tetracycline or presence of ponasterone to induce gene expression were tested. Expression of lacZ was controlled by ponasterone, but {beta}-galactosidase activity was limited to 10–20% of cells. In contrast, the tetracycline-controlled expression system gave a low basal activity and was highly inducible in almost 100% of cells. Inducible expression was also obtained in almost 100% of cells infected with baculoviruses in which an HCV minigenome was placed downstream of the tetracycline-inducible promoter and upstream of either a hammerhead or hepatitis {delta} virus ribozyme. Northern blot analysis was consistent with accurate cleavage of the minigenome transcript by the hepatitis {delta} virus ribozyme. Finally, regulable transcript production and viral polypeptide processing could be demonstrated in HepG2 cells infected with baculoviruses bearing the full-length HCV genome. This system thus provides a novel tool for the analysis of HCV replication and host–cell interactions