A proposed coast-wide reference monitoring system for evaluating wetland restoration trajectories in Louisiana

Wetland restoration efforts conducted in Louisiana under the Coastal Wetlands Planning, Protection and Restoration Act require monitoring the effectiveness of individual projects as well as monitoring the cumulative effects of all projects in restoring, creating, enhancing, and protecting the coastal landscape. The effectiveness of the traditional paired-reference monitoring approach in Louisiana has been limited because of difficulty in finding comparable reference sites. A multiple reference approach is proposed that uses aspects of hydrogeomorphic functional assessments and probabilistic sampling. This approach includes a suite of sites that encompass the range of ecological condition for each stratum, with projects placed on a continuum of conditions found for that stratum. Trajectories in reference sites through time are then compared with project trajectories through time. Plant community zonation complicated selection of indicators, strata, and sample size. The approach proposed could serve as a model for evaluating wetland ecosystems.     

Removal of aldrin, dieldrin, heptachlor, and heptachlor epoxide using activated carbon and/or Pseudomonas fluorescens free cell cultures

Degradation of aldrin (1,2,3,4,10,10-Hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5-8-dimethanonaphthalene), heptachlor (1H-1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano indene), dieldrin (1aalpha,2beta,2aalpha,3beta,6beta,6aalpha,7beta,7aalpha)-3,4,5,6,9,9-Hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-d-methanonaphtha[2,3-b]oxirene, and heptachlor epoxide (1aalpha, 1bbeta,2alpha,5alpha,5alphabeta,6beta,6aalpha-2,3,4,5,6,7,7-Heptachloro-1a,1b,5,5a,6,6a-hexahydro-2,5-methano-2H-inden[1,2-b]-oxirene) was tested using free cultures of Pseudomonas fluorescens under controlled conditions. Pesticide concentrations were monitored by gas chromatography during 120 h. Percentages of degradation and biodegradation rates (BDR) were calculated. Data showed a trend suggesting a relation between chemical structure and degradability. Degradation kinetics for each pesticide tested showed that the highest degradation rates were found in the first 24 h. Kinetics data were adjusted to an empirical equation in order to predict their behavior, and the correlation coefficients obtained were satisfactory. Gas chromatography/mass spectrometry (GC/MS) analysis of the final extracts allowed the identification of chlordene and monodechlorodieldrin, which have been reported as final metabolite produced in the biodegradation of this kind of compounds. Regarding adsorption of pesticides on activated vegetal carbon, we concluded that removal efficiencies between 95.45 and 97.18% can be reached, depending on the pesticide and the carbon dose applied. The values for K from the Freundlich equation were quite similar for the four pesticides (between 1.0001 and 1.04), whereas the n values were quite different for each pesticide in the following order of affinity: dieldrin > aldrin > heptachlor epoxide > heptachlor. Equilibrium times, very important for scaling up the process, were between 43 min and 1 h, for the heptachlor epoxide and the heptachlor, respectively.     

A peaceful zone bordering two Argentine ant (Linepithema humile) supercolonies

In invasion areas, the Argentine ant (Linepithema humile) forms huge supercolonies with free exchange of individuals among nests. Two continental supercolonies on the French mediterranean coast, the Main European supercolony and the Corsican supercolony, are known to contain workers showing moderate to high levels of inter-supercolony aggression. We performed chemical and behavioral assays using workers from eight coastal sites in southeastern France covering a geographical zone that includes nests of the two supercolonies, to determine the nature of worker interactions in a supercolony boundary zone. We examined how the chemical and behavioral clines vary across the borders of the Main and Corsican supercolonies. Our results on Giens peninsula and Porquerolles island populations bordering the Main supercolony reveal the existence of a peaceful border zone with no aggression between workers of the Main supercolony and the Corsican supercolony. The chemical results, however, exhibited qualitative similarity to those observed in the Corsican supercolony and revealed both quantitative and qualitative chemical differences from those observed in the Main supercolony. These peaceful populations may result from fusion and/or genetic crosses between the two supercolonies, and we hypothesize that such peaceful border zones are instrumental in the evolution of supercolonies.     

Seasonal variability in CDOM absorption and fluorescence properties in the Barataria Basin, Louisiana, USA

Absorption and fluorescence properties of chromophoric dissolved organic matter(CDOM) along a 124 km transect in the Barataria Basin,a large estuary located in Louisiana,USA,were investigated during high and low flow periods of the Mississippi River in the spring and winter of 2008-2009. Mean CDOM absorption at 355 nm from the marine to the freshwater end member stations ranged from(3.25 ± 0.56) to(20.76 ± 2.43) m-1 for the three month high flow period whereas it varied from(1.48 ± 1.08) to(25.45 ± 7.03) m-1 for the same stations during low flow period. Corresponding salinity values at these stations indicated the influence of river and shelf exchanges in the lower basin and precipitation and runofl in the upper basin. An inverse relationship of CDOM absorbance and fluorescence with salinity observed in the basin could be a useful indicator of salinity. CDOM fluorescence also varied over a large range showing an approximately 8 to 12-fold increase between the marine and freshwater end members for the two flow seasons. Excitation-emission matrix spectral plots indicated the presence of various fluorescence components with highest being the A-peak,lowest the T-peak,and the C and M-peaks showing similar trends along the transect. During low flow season the A/C ratio were well correlated with station locations indicating increased terrestrial influence towards the upper basin. CDOM absorption and fluorescence at 355 nm were highly correlated and independent of CDOM sources suggesting that fluorescence could be used to characterize CDOM in the basin.     

Impacts of quarrying activities on the environment and livelihood of people in Border II sub-location,Nyando sub-county,Kisumu County,Kenya

The aim of the study was to assess the impacts of quarrying activities on the environment and livelihood of people in the Border II sub-location. Primary data was collected through questionnaires, Key Informant Interviews, Focus Group Discussion, laboratory analysis and observations. Whereas, secondary data was obtained from Landsat satellite images, journals, articles, books and reports. The acquired data were analyzed using excel and Arc GIS; and presented into tables and figures. The Land use/cover change analysis from the satellite images of the area showed that quarry lands have increased by 5.2 Ha (0.26%). Quarrying activities in the area were perceived to have both positive and negative impacts on the livelihood of people and the environment. Some of the most serious environmental problems were; dust pollution (82%), noise (76%), land degradation (74%), vegetation loss (60%) and vibration (52%). Whereas, negative socioeconomic impacts were; building cracks (54%), injuries (36%), school dropouts (35%), roads damages (33%), child labor (31%) and crop effects (30%). Moreover, 45% of the area residents and 44% of the quarry workers have experienced health problems related to quarrying activities. Nevertheless, there was a significant relationship between quarrying activities and the environmental as well as human health problems in the area (p<0.05). The positive impacts identified are; employment, roads improvement, security, CSR, building materials, business opportunities, among others. To mitigate the negative impacts, the quarry operators should develop and implement an Environmental and Social management Plan, including fair compensation of the project which affect a person, relocation of near homes, environmental pollution control, public participation, scaling down blasting activities, and strict policies compliance and enforcement.     

Contribution of Liquefied Petroleum Gas to Air Pollution in the Metropolitan Area of Mexico City

ABSTRACT

An estimation of hydrocarbon emissions caused by the consumption of liquefied petroleum gas (LPG) in the Metropolitan Area of Mexico City (MAMC) is presented. On the basis of experimental measurements at all points of handling, during the distribution process, and during the consumption of LPG in industrial devices and domestic appliances, an estimated 76,414 tons/year are released to the air. The most important contribution is found during the domestic consumption of LPG (70%); this makes the control initiatives available to the consumer. By developing a control program of LPG losses, a 77% reduction in emission is expected in a 5-yr period.

The calculated amounts of LPG emissions when correlated with the consumption of LPG, combined with information from air samples from the MAMC, do not point to LPG emissions as the most important factor contributing to tropospheric ozone in the air in Mexico City.     

Freeze survival of the cyanobacteria Microcoleus chthonoplastes without cryoprotector

A Microcoleus chthonoplastes strain SC7B9002-1 isolated from microbial mats in tidal channels from San Carlos, Baja California Sur, Mexico was subjected to short- (15 days) and long-term (2 years) conservation assays in liquid nitrogen (-196 degrees C) using cryoprotective agents, such as 5% DMSO, 20% PVP-40, and 20% glycerol. Survival rate, chlorophyll a, protein, and nucleic acids content were observed in each case. Interesting growth and a significant increase in protein content was observed when no cryoprotectant was used during liquid nitrogen immersion. In the absence of a cryoprotectant, M. chthonoplastes lost their typical shape resembled spheroplasts, and recovery cultivation times after freezing were 5 and 25 days (short and long-term, respectively). Recovery from long-term preservation with 5% DMSO took 15 days. PVP and glycerol did not allow recovery of viable cells. The survival of M. chthonoplastes to freezing without cryoprotectant and the adaptive mechanisms that allow surviving under freezing conditions are discussed.     

Deducing an upper bound to the horizontal eddy diffusivity using a stochastic Lagrangian model

We present a method for estimating the upper bound of the horizontal eddy diffusivity using a non-stationary Lagrangian stochastic model. First, we identify a mixing barrier using a priori evidence (e.g., aerial photographs or satellite imagery) and using a Lagrangian diagnostic calculated from observed or modeled spatially non-trivial, time-dependent velocities [for instance, the relative dispersion (RD) or finite time Lyapunov exponent (FDLE)]. Second, we add a stochastic component to the observed (or modeled) velocity field. The stochastic component represents sub-grid stochastic diffusion and its mean magnitude is related to the eddy diffusivity. The RD of Lagrangian trajectories is computed for increasing values of the eddy diffusivity until the mixing barrier is no longer present. The value at which the mixing barrier disappears provides a dynamical estimate of the upper bound of the eddy diffusivity. The erosion of the mixing barrier is visually observed in numerical simulations, and is quantified by computing the kurtosis of the RD at each value of the eddy diffusivity. We demonstrate our method using the double gyre circulation model and apply it to high frequency (HF) radar observations of surface currents in the Gulf of Eilat.     

Migration,markets, and mangrove resource use on Kosrae,Federated States of Micronesia

Kosrae, Federated States of Micronesia, is a prototype of an island economy prone to economic crowding. Average family size is large, the habitable land area is small, economic activity is limited, and household dependence on natural resources for fuel and food is high. We analyze how economic crowding--and its mitigation through trade and migration policies--affects mangrove resource use. A comparison of household survey data from 1996 and 2000 indicates that despite decreases in US aid and public-sector jobs, average household consumption of mangrove resources has not increased. Migration and remittances have allowed the purchase of imported fuel and building materials substituting for mangrove wood. Despite changing preferences and shifts toward import consumption, population growth and further declines in US financial support will likely cause aggregate demand for mangrove and upland wood to rise. Moreover, continued emigration may accelerate the export of mangrove crabs to off-island Kosraeans.