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Castaneda-Moya E.,Louisiana State University | Twilley R.R.,Louisiana State University | Rivera-Monroy V.H.,Louisiana State University | Marx B.D.,Louisiana State University | And 2 more authors.
Ecosystems | Year: 2011

Patterns of mangrove vegetation in two distinct basins of Florida Coastal Everglades (FCE), Shark River estuary and Taylor River Slough, represent unique opportunities to test hypotheses that root dynamics respond to gradients of resources, regulators, and hydroperiod. We propose that soil total phosphorus (P) gradients in these two coastal basins of FCE cause specific patterns in belowground biomass allocation and net primary productivity that facilitate nutrient acquisition, but also minimize stress from regulators and hydroperiod in flooded soil conditions. Shark River basin has higher P and tidal hydrology with riverine mangroves, in contrast to scrub mangroves of Taylor basin with more permanent flooding and lower P across the coastal landscape. Belowground biomass (0-90 cm) of mangrove sites in Shark River and Taylor River basins ranged from 2317 to 4673 g m-2, with the highest contribution (62-85%) of roots in the shallow root zone (0-45 cm) compared to the deeper root zone (45-90 cm). Total root productivity did not vary significantly among sites and ranged from 407 to 643 g m-2 y-1. Root production in the shallow root zone accounted for 57-78% of total production. Root turnover rates ranged from 0.04 to 0.60 y-1 and consistently decreased as the root size class distribution increased from fine to coarse roots, indicating differences in root longevity. Fine root biomass was negatively correlated with soil P density and frequency of inundation, whereas fine root turnover decreased with increasing soil N:P ratios. Lower P availability in Taylor River basin relative to Shark River basin, along with higher regulator and hydroperiod stress, confirms our hypothesis that interactions of stress from resource limitation and long duration of hydroperiod account for higher fine root biomass along with lower fine root production and turnover. Because fine root production and organic matter accumulation are the primary processes controlling soil formation and accretion in scrub mangrove forests, root dynamics in the P-limited carbonate ecosystem of south Florida have a major controlling role as to how mangroves respond to future impacts of sea-level rise. © 2011 Springer Science+Business Media, LLC. Source

Nguyen Q.T.,Coventry University | Naguib R.N.G.R.,Coventry University | Wickramasinghe N.,RMIT University | Shaker M.H.,Ecology and Environment Inc.
International Journal of Biomedical Engineering and Technology | Year: 2011

Developed countries, where the standards of the environment in ambient and indoor areas are in line with the World Health Organization Air Quality Standards, have widely acknowledged and are fully aware of the importance of this issue. However, many developing countries, such as the Philippines, suffer from high concentrations of ambient Particulate Matter and from high rates of mortality from Cardiovascular Disease (CVD). Therefore, the aim of this paper is to understand the possible relationships between airborne pollutants and CVD in the Philippines and to raise the awareness of the government, citizens and specialists to address this issue. © 2011 Inderscience Enterprises Ltd. Source

Kauffman-Axelrod J.L.,Ecology and Environment Inc. | Steinberg S.J.,Humboldt State University
Wetlands | Year: 2010

Recent geographic information system (GIS) mapping of Oregon's tidal wetlands identified over 2,000 potential restoration areas. Given the large number of restoration opportunities, we developed automated GIS tools to assist resource managers in prioritizing areas with less hydrologic alteration and more favorable landscape scale metrics. The Coos estuary and watershed was used as an example of a regional application. We developed nine GIS tools using scripting techniques to prioritize among 530 potential restoration sites using widely available state-wide datasets. Parameters evaluated were limited to factors affecting a site's hydroperiod at multiple scales and reflecting consideration of ecological principles. Tabular model output was used to prioritize potential restoration sites. Prioritization ranks were calculated using a three-tier weighted summation designated by Coos estuary restoration practitioners. Standardized ranks ranged from 0.479-1.000 on a zero to one scale. Higher ranks indicate more favorable landscape scale metrics and less cumulative hydrologic alteration. Model output, standardized parameter scores, and prioritized rankings of potential restoration sites were stored in a Microsoft Access database coupled with a geodatabase containing spatial geometry. These automated tools present repeatable and flexible methods for evaluation and prioritization of a large number potential restoration sites in Oregon. © 2010 Society of Wetland Scientists. Source

Zhu Y.,University of Florida | Gu B.,University of Florida | Irick D.L.,University of Florida | Ewe S.,Ecology and Environment Inc. | And 5 more authors.
Environmental Pollution | Year: 2014

Abstract Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglades. A total of 93 surface soil and 3 soil core samples were collected from 7 degraded/ghost and 34 live tree islands. The mean Hg concentration in surface soils of ghost tree islands was low and similar to marsh soil. For live tree islands, Hg concentrations in the surface head region were considerably greater than those in mid and tail region, and marsh soils. Hg concentrations in bird guano (286 μg kg-1) were significantly higher than those in mammal droppings (105 μg kg-1) and plant leaves (53 μg kg-1). In addition, Hg concentrations and δ15N values displayed positive correlation in soils influenced by guano. During 1998-2010, estimated annual Hg deposition by guano was 148 μg m-2 yr-1 and ∼8 times the atmospheric deposition. Source

Roy D.,Nicholls State University | Roy D.,North Dakota State University | Hassan K.,Ecology and Environment Inc. | Boopathy R.,Nicholls State University
Journal of Industrial Microbiology and Biotechnology | Year: 2010

The United States Marine Shrimp Farming Program (USMSFP) introduced a new technology for shrimp farming called recirculating raceway system. This is a zero-water exchange system capable of producing high-density shrimp yields. However, this system produces wastewater characterized by high levels of ammonia, nitrite, and nitrate due to 40% protein diet for the shrimp at a high density of 1,000 shrimp per square meter. The high concentrations of nitrate and nitrite (greater than 25 ppm) are toxic to shrimp and cause high mortality. So treatment of this wastewater is imperative in order to make shrimp farming viable. One simple method of treating high-nitrogen wastewater is the use of a sequencing batch reactor (SBR). An SBR is a variation of the activated sludge process, which accomplishes many treatment events in a single reactor. Removal of ammonia and nitrate involved nitrification and denitrification reactions by operating the SBR aerobically and anaerobically in sequence. Initial SBR operation successfully removed ammonia, but nitrate concentrations were too high because of carbon limitation in the shrimp production wastewater. An optimization study revealed the optimum carbon to nitrogen (C:N) ratio of 10:1 for successful removal of all nitrogen species from the wastewater. The SBR operated with a C:N ratio of 10:1 with the addition of molasses as carbon source successfully removed 99% of ammonia, nitrate, and nitrite from the shrimp aquaculture wastewater within 9 days of operation. © Society for Industrial Microbiology 2010. Source

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