Social–ecological system responses to Hurricane Sandy in the Hudson-Raritan Estuary

The impact of Hurricane Sandy on the Hudson-Raritan estuary (HRE) provided a valuable case study for exploring interactions between long-term environmental degradation, new climatic disturbance stressors, and human behavioral responses. We extend previous research on the ecological effects of major storms to compare water quality and biological parameters three years before and three years after Hurricane Sandy and consider how ecosystem shifts relate to anglers’ perceptions. Results indicate that water clarity and nutrients returned to pre-storm conditions in about one year, while shifts in the biological community, including a significant increase in harmful algal species and declines in zooplankton and Atlantic menhaden, persisted for multiple years, and anglers continued to fish amidst ecosystem decline. Biotic recovery time in the HRE was longer than reports for other shallow estuaries frequently disturbed by hurricanes. Ecological and social responses suggest that the post-storm regime shifts and continued fishing pressure could further environmental degradation.     

A risk assessment study of water quality,biota, and legacy sediment prior to small dam removal in a tributary to the Delaware River

The proposed removal of three run-of-river dams (all ≤5-m height) in eastern Pennsylvania along lower Bushkill Creek, a tributary of the Delaware River, has provided a valuable opportunity for multidisciplinary research involving the collection of more than 5 years of pre-removal monitoring data, analysis of heavy metals in legacy sediment cores, and associated toxicity assays to determine the singular and interactive effects of lead, copper, and cadmium on survival and behavior of a common macroinvertebrate found in Bushkill Creek. Monitoring data were collected from sites approximately 35 m upstream and downstream of dams and reference sites located approximately 5 km upstream of all dams. Results indicate that oxygen levels, macroinvertebrate diversity, and proportion of sensitive taxa were significantly lower upstream and downstream of dams in comparison with upstream reference reaches. The strong correlation between water quality and macroinvertebrates in this system implies that removal of the lower three dams would lead to improvements in water quality, biotic integrity, and resilience in lower Bushkill Creek. Sediment analyses and toxicity assays suggest that dam removal and sediment mobilization may route contaminated sediments downstream at concentrations that may harm more sensitive biota. However, macroinvertebrate mortality and behavior were not significantly different from clean water controls for the large majority of toxicity assays. All together, these results suggest that dams 1–3 are good candidates for successful stream restoration but that the removals would best be planned in a way that mitigates potential impacts of contaminated legacy sediment.     

Seasonal stresses shift optimal intertidal algal habitats

We studied how the growth, reproduction, and survival of a common intertidal rockweed (Fucus distichus) varied across its tidal elevation at 14 sites around San Juan Island, Washington, USA in spring–summer and fall-winter seasons. We also measured a suite of environmental factors including temperature, light, emersion time, slope, fetch, and herbivory. To interpret the response of Fucus we included measurements of phlorotannins and carbon storage compounds (mannitol, laminarin). Growth and reproduction exhibited parallel patterns across tidal zones and sites. Tidal zone was a significant source of variation for many Fucus response variables, whereas variation between sites was high but not generally a significant factor explaining Fucus growth and physiology. Unexpectedly, the tidal zone in which Fucus achieved its highest growth and reproduction switched between seasons. High zone thalli grew and reproduced better than Mid zone thalli in fall but not in spring. This result can be explained by different combinations of factors influencing Fucus in each season. In spring, longer emersion times due to daytime low tides resulted in lower growth rates higher on the shore, likely due to carbon limitation. In fall during nighttime low tides, emersion and carbon limitation stresses were minimal. Overall, fall growth was lower than spring growth, but low fall light was not responsible. Instead, warmer average fall temperatures in the High zone apparently favored growth and reproduction relative to the Mid zone. In contrast, Mid zone thalli were subjected to more intense herbivory and hydrodynamic stress associated with wave exposure and steep substrata during the fall. At least for some seaweeds, living in the presumably more stressful high zone can actually confer higher integrated performance.     

A comparison of disposal methods for on-site sewage facilities within the state of Texas,USA

Currently, 1.5 million homes in Texas, USA utilize an on-site sewage facility to manage their household waste. This study compares the conventional septic dispersal technology of perforated pipe drain field with two of the new technologies recently implemented in Texas, multi-pipe and chamber systems, determining if soil classification and climate are influencing factors in functional ability for each of the technologies. There is no statistical significance for failure of a system with respect to system type or climate zone. The textural classification of soil is a statistically significant variable in septic system failures. Soil type III, which includes the clay groups except pure clays and silty clay, appears to significantly influence system failures. Additionally, occupant misuse and lack of maintenance are contributing factors to system failure.     

Spatial and temporal variations and mobile source emissions of polycyclic aromatic hydrocarbons in Quito, Ecuador

Motor vehicles are a major source of air pollution in Quito, Ecuador; however, little work has been done to characterize spatial and temporal variations in traffic-related pollutants, or to measure pollutants in vehicle emissions. We measured PAH continuously for one year at two residential sites in Quito, and PAH and traffic patterns for one week near a busy roadway. Morning rush-hour traffic and temperature inversions caused daily PAH maxima between 06:00 and 08:00. SO₂, NO_x, CO, and PM_2.5 behaved similarly. At the residential sites PAH levels during inversions were 2-3-fold higher than during the afternoon, and 10-16-fold higher than 02:00-03:00 when levels were lowest. In contrast, at the near-roadway site, PAH concentrations were 3-6-fold higher than at the residential sites, and the effects of inversions were less pronounced. Cars and buses accounted for >95% of PAH at the near-roadway site. Near-roadway PAH concentrations were comparable to other polluted cities.     

Fungal spore fragmentation as a function of airflow rates and fungal generation methods

The aim of this study was to characterise and quantify the fungal fragment propagules derived and released from several fungal species (Penicillium, Aspergillus niger and Cladosporium cladosporioides) using different generation methods and different air velocities over the colonies. Real time fungal spore fragmentation was investigated using an Ultraviolet Aerodynamic Particle Sizer (UVASP) and a Scanning Mobility Particle Sizer (SMPS). The study showed that there were significant differences (p < 0.01) in the fragmentation percentage between different air velocities for the three generation methods, namely the direct, the fan and the fungal spore source strength tester (FSSST) methods. The percentage of fragmentation also proved to be dependent on fungal species. The study found that there was no fragmentation for any of the fungal species at an air velocity ≤0.4 m s^?1 for any method of generation. Fluorescent signals, as well as mathematical determination also showed that the fungal fragments were derived from spores. Correlation analysis showed that the number of released fragments measured by the UVAPS under controlled conditions can be predicted on the basis of the number of spores, for Penicillium and A. niger, but not for C. cladosporioides. The fluorescence percentage of fragment samples was found to be significantly different to that of non-fragment samples (p < 0.0001) and the fragment sample fluorescence was always less than that of the non-fragment samples. Size distribution and concentration of fungal fragment particles were investigated qualitatively and quantitatively, by both UVAPS and SMPS, and it was found that the UVAPS was more sensitive than the SMPS for measuring small sample concentrations, whilethe results obtained from the UVAPS and SMAS were not identical for the same samples.     

Mapping bundles of ecosystem services reveals distinct types of multifunctionality within a Swedish landscape

Ecosystem services (ES) is a valuable concept to be used in the planning and management of social–ecological landscapes. However, the understanding of the determinant factors affecting the interaction between services in the form of synergies or trade-offs is still limited. We assessed the production of 16 ES across 62 municipalities in the Norrström drainage basin in Sweden. We combined GIS data with publically available information for quantifying and mapping the distribution of services. Additionally, we calculated the diversity of ES for each municipality and used correlations and k-means clustering analyses to assess the existence of ES bundles. We found five distinct types of bundles of ES spatially agglomerated in the landscape that could be explained by regional social and ecological gradients. Human-dominated landscapes were highly multifunctional in our study area and urban densely populated areas were hotspots of cultural services.     

Performance comparison of tin oxide anodes to commercially available dimensionally stable anodes

Dimensionally stable anodes (DSAs) demonstrate potential for the electrochemical treatment of industrial waste streams and disinfection of effluent. Oxidation by laboratory-prepared tin oxide DSAs was compared with that of commercially available ruthenium oxide, iridium oxide, and mixed metal oxide DSAs, using hexanol as a probe molecule. The performance of the four anodes was similar in two-chamber reactors, in which the anode cell was separated from the cathode cell by a Nafion membrane, which allows transmission of current between the chambers, but not passage of chemical constituents. The anodes were then evaluated in single-cell reactors, which are more representative of potential treatment and disinfection applications. However, in the single-cell reactors, the tin oxide anodes were significantly more effective at oxidation and generated higher quality cyclic voltammograms than the other DSAs. These results suggest that tin oxide anodes have greater potential than the three commercially available DSAs tested for industrial waste stream treatment and effluent disinfection.     

A Processing,Characterization and Marine Biodegradation Study of Melt-Extruded Polyhydroxyalkanoate (PHA) Films

A series of polyhydroxyalkanoates (PHA), all containing 1% nucleating agent but varying in structure, were melt-processed into films through single screw extrusion techniques. This series consisted of three polyhydroxybutyrate (PHB) and three polyhydroxybutyrate-valerate (PHBV) resins with varying valerate content. Processing parameters of temperature in the barrel (165–173 °C) and chill rolls (60 °C) were optimized to obtain cast films. The gel-permeation chromatography (GPC) results showed a loss of 8–19% of the polymer’s initial molecular weight due to extrusion processing. Modulated differential scanning calorimetry (MDSC) displayed glass transition temperatures of the films ranging from −4.6 to 6.7 °C depending on the amount of crystallinity in the film. DSC data were also used to calculate the percent crystallinity of each sample and slightly higher crystallinity was observed in the PHBV series of samples. X-ray diffraction patterns did not vary significantly for any of the samples and crystallinity was confirmed with X-ray data. Dynamic mechanical analysis (DMA) verified the glass transition trends for the films from DSC while loss modulus (E′) reported at 20 °C showed that the PHBV (3,950–3,600 MPa) had the higher E′ values than the PHB (3,500–2,698 MPa) samples. The Young’s modulus values of the PHB and PHBV samples ranged from 700 to 900 MPa and 900 to 1,500 MPa, respectively. Polarized light microscopy images revealed gel particles in the films processed through single-screw extrusion, which may have caused diminished Young’s modulus and tensile strength of these films. The PHBV film samples exhibited the greatest barrier properties to oxygen and water vapor when compared to the PHB film samples. The average oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) for the PHBV samples was 247 (cc-mil/m²-day) and 118 (g-mil/m²-day), respectively; while the average OTR and WVTR for the PHB samples was 350 (cc-mil/m²-day) and 178 (g-mil/m²-day), respectively. Biodegradation data of the films in the marine environment demonstrated that all PHA film samples achieved a minimum of 70% mineralization in 40 days when run in accordance with ASTM 6691. For static and dynamic incubation experiments in seawater, microbial action resulting in weight loss as a function of time showed all samples to be highly biodegradable and correlated with the ASTM 6691 biodegradation data.