The influence of<Emphasis Type="Italic">Phragmites</Emphasis> (common reed) on the distribution,abundance, and potential prey of a resident marsh fish in the Hackensack Meadowlands,New Jersey

This study investigates the influence ofPhragmites australis (common reed) invasion on the habitat of the resident marsh fish,Fundulus heteroclitus (mummichog) in the Hackensack Meadowlands, New Jersey. These abundant fish play an important role in the transfer of energy from the marsh surface to adjacent subtidal waters and thus estuarine food webs. The objectives of this 2-yr study (1999 and 2000) were to compare the distribution and abundance of the eggs, larvae, juveniles, and adults of mummichog and their invertebrate prey inhabitingSpartina alterniflora-dominated marshes withPhragmites-dominated marshes, and to experimentally investigate the influence of marsh surface microtoprography on larval fish abundance withinPhragmites-dominated marshes. In 2000, we verified that egg deposition does occur inPhragmites-dominated marshes. In both years, the abundance of larvae and small juveniles (4–20 mm TL) inS. alterniflora was significantly greater than inPhragmites-dominated marshes, while larger juveniles and adults (>20 mm TL) were similarly abundant in both habitat types. The overall abundance of larvae and small juveniles was significantly greater in experimentalPhragmites plots in which microtopography was manipulated to resemble that ofSpartina marshes than inPhragmites control plots. Major groups of invertebrate taxa differed between marsh types with potential prey for larval fish being significantly more abundant inS. alterniflora marshes.Phragmites-dominated marshes may not provide the most suitable habitat for the early life-history stages of the mummichog. The low abundance of larvae and small juveniles inPhragmites marshes is likely due to inadequate larval habitat and perhaps decreased prey availability for these early life history stages.     

Development of a brownfield inventory for prioritizing funding outreach in Tucson,Arizona

Fear of liability from the 1980 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) has prompted developers to build pre...     

Dimension of the Earth's General Ellipsoid

The problem of specifying the Earth's mean (general)ellipsoid is discussed. This problem has been greatly simplified in the era of satellite altimetry, especially thanks to the adopted geoidal geopotential value, W₀ = (62 636 856.0 ± 0.5) m² s^-2.Consequently, the semimajor axis a of the Earth's mean ellipsoid can be easily derived. However, an a priori condition must be posed first. Two such a priori conditions have been examined, namely an ellipsoid with the corresponding geopotential that fits best W₀ in the least squares sense and an ellipsoid that has the global geopotential average equal to W₀. It has been demonstrated that both a priori conditions yield ellipsoids of the same dimension, with a–values that are practically identical to the value corresponding to the Pizzetti theory of the level ellipsoid: a = (6 378 136.68 ± 0.06) m.     

Chronic herbicide exposures affect the sensitivity and community structure of tropical benthic microalgae

The effects of prolonged exposure to low concentrations of herbicides on tropical periphyton (biofilm) communities are largely unknown. Tropical estuarine biofilms established in microcosms were therefore exposed to diuron (photosystem-II-inhibitor) at 2-16μg L(-1) for 4 weeks. The biofilms, consisting of diatoms, filamentous brown algae and cyanobacteria, developed a tolerance to diuron during this period as measured by Phyto-PAM fluorometry. Microscopy and pigment analysis revealed that this decrease in sensitivity was accompanied by a shift in species composition towards communities dominated by diatoms. The combination of techniques enabled the first identification of pollution-induced community tolerance (PICT) in tropical estuarine periphyton in response to chronic herbicide exposures. Community composition changed compared to controls at environmentally relevant concentrations of 1.6μg L(-1), while development of PICT was evident at 6.5μg L(-1) diuron, with no recovery (over 2 weeks) in uncontaminated water, indicating chronic pollution induced shifts in community structure.     

Community resilience to tsunamis along the Southeastern Pacific: a multivariate approach incorporating physical,environmental, and social indicators

Tsunamic events are a frequent hazard to coastal towns. Despite this, the extent to which resilience models can be applied to coastal towns as well as the aspects that should be considered when doing so have not been fully evaluated. There is little information regarding the specific indicators that allow cities to better cope and adapt to the impacts of tsunamis, and this information is especially scarce for developing countries such as Chile. The main objective of this study is to develop a resilience model to explore the extent to which local characteristics influence the resilience of Chilean coastal communities to tsunami hazards. Accordingly, this study presents the Coastal Community Resilience model (The CORE model) for exploring the adaptive capacity of coastal areas affected by tsunamis. This model was then applied to fourteen coastal villages, distributed within four towns, three communes, and two regions of Chile. Data comprising 21 indicators that address the physical, environmental, and social resilience aspects of the villages were obtained on-site and from governmental and municipality databases; these data were then subjected to multivariate analysis in order to determine which indicators most and least affect resilience and whether indicators affect resilience positively or negatively. Variation in resilience among the villages was explained by similarities and differences in the administrative-political, urban, rural, and indigenous characteristics of the study areas. In addition to these results, we discuss land use planning considerations to build community resilience, and we provide insight into the utility of the resilience model proposed here. Overall, our findings shed light on gaps in planning policies and opportunities for planning coastal resilient communities, particularly for those where data of explicit indicators are scarce like in Chile and other developing countries.