Effects of Watershed Impervious Cover on Dissolved Silica Loading in Storm Flow1

Abstract: Dissolved silica (DSi) availability is a factor that affects the composition of algal populations in aquatic ecosystems. DSi cycling is tightly linked to the hydrological cycle, which is affected by human alterations of the landscape. Development activities that increase impervious cover change watershed hydrology and may increase the discharge of DSi‐poor rainwater and decrease the discharge of DSi‐rich ground water into aquatic ecosystems, possibly shifting algal community composition toward less desirable assemblages. In this study, DSi loadings from two adjacent coastal watersheds with different percent impervious cover were compared during four rain and five nonrain events. Loadings in the more impervious watershed contained a significantly larger proportion of surface runoff than base flow (ground‐water discharge) and had lower [DSi] water during rain events than the less impervious watershed. Application of the Soil Conservation Service Curve Number (CN) method showed that the minimum rainfall height necessary to yield runoff was significantly lower for the more impervious watershed, implying that runoff volumes increase with impervious cover as well as the frequency of runoff‐yielding events. Empirical data collected during this study and estimates derived from the CN method suggest that impervious cover may be responsible for both short‐term DSi limitation during rain events as well as long‐term reduction of DSi inputs into aquatic ecosystems.     

Aromatic Copolyester-based Nano-biocomposites: Elaboration, Structural Characterization and Properties

Biodegradable polymers are one of the most promising ways to replace non-degradable polymers. But, to be a real alternative to classical synthetic polymers and find applications, biopolymer (biodegradable polymer) properties have to be enhanced. Nano-biocomposites, which are obtained by incorporation of nanofillers into a biomatrix, are an interesting way to achieve these improvements. Modified and unmodified montmorillonites have been introduced into a biodegradable aromatic copolyester, poly(butylene adipate-co-terephthalate) (PBAT). Structural characterization, thermal and mechanical tests have been carried out to understand better the relations between the nanofillers structuring and the final nano-biocomposite properties. Main results show that clay incorporation and the obtained intercalated structures improve PBAT properties (enhanced thermal stability, increased stiffness) and thus may increase the attractiveness of this biopolymer.     

Semilobar holoprosencephaly in a 46,XY female fetus

We report the prenatal echographic diagnosis of holoprosencephaly (HPE) at 11 weeks' gestation. Fetopathological examination revealed an unusual variant of semilobar HPE with middle interhemispheric fusion associated with sex-reversal: 46,XY normal male karyotype, normal external and internal female genitalia and streak gonads. Copyright © 2001 John Wiley & Sons, Ltd.     

Leachate recirculation: moisture content assessment by means of a geophysical technique

Bioreactor technology is a waste treatment concept consisting in speeding up the biodegradation of landfilled waste by optimizing its moisture content through leachate recirculation. The measurement of variations in waste moisture content is critical in the design and control of bioreactors. Conventional methods such as direct physical sampling of waste reach their limits due to the interference with the waste matrix. This paper reviews geophysical measurements such as electrical direct current and electromagnetic slingram methods for measuring the electrical conductivity. Electrical conductivity is a property, which is linked to both moisture and temperature and can provide useful indications on the biodegradation environment in the waste mass. The study reviews three site experiments: a first experimentation shows the advantages (correlation between conductive anomaly and water seepage) but also the limits of geophysical interpretation; the two other sites allow the leachate recirculation to be tracked by studying the relative resistivity variation versus time from electrical 2D imaging. Even if some improvements are necessary to consider geophysical measurements as a real bioreactor monitoring tool, results are promising and could lead to the use of electrical 2D imaging in bioreactor designing.     

Carbon trading: time for industry involvement

Carbon trading is no longer just theory. Infant markets already exist and, in 2002, they traded perhaps $10 million worth of emissions allowances. We estimate conservatively that, by 2010, the EU scheme will trade as much as $1 billion in allowances each year. The motor of the carbon markets is a worldwide effort to reduce emissions of greenhouse gases. Its most visible symbol is the Kyoto Protocol of 1997, formally known as the United Nations Framework Convention on Climate Change. Even if Kyoto is not ratified and, despite the US's decision to opt out of the treaty, the genie of greenhouse-gas reduction is out of the bottle. We believe that trading of greenhouse gases will be a real, day-to-day activity by 2010, almost certainly in Europe and probably in Canada and Japan. Carbon trading in these areas will affect the US, whether or not America sets up a programme of its own. The conclusion of this study is that industry should get involved in defining carbon trading-and now-to advance and defend their interests. Interest should be greatest among producers and users of the greenhouse gases other than carbon dioxide, namely methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride.     

A field evaluation of a piezo-optical dosimeter for environmental monitoring of nitrogen dioxide

Measurements of 8-hour time-weighted average NO(2) concentrations are reported at 7 different locations in the region of Dunkirk over 5 consecutive days using PiezOptic monitoring badges previously calibrated for the range 0-70 ppb together with data from chemiluminescent analysers in 5 sites (4 fixed and one mobile). The latter facilities also provided data on ozone and NO concentrations and meteorological conditions. Daily averages from the two pairs of badges in different types of sampling cover in each site have been compared with data from the chemiluminescent analysers, and found largely to agree within error margins of +/-30%. Although NO(2) and ozone concentrations were low, rendering detailed discussion impossible, the general features followed expected patterns.     

Longevity can buffer plant and animal populations against changing climatic variability

Both means and year-to-year variances of climate variables such as temperature and precipitation are predicted to change. However, the potential impact of changing climatic variability on the fate of populations has been largely unexamined. We analyzed multiyear demographic data for 36 plant and animal species with a broad range of life histories and types of environment to ask how sensitive their long-term stochastic population growth rates are likely to be to changes in the means and standard deviations of vital rates (survival, reproduction, growth) in response to changing climate. We quantified responsiveness using elasticities of the long-term population growth rate predicted by stochastic projection matrix models. Short-lived species (insects and annual plants and algae) are predicted to be more strongly (and negatively) affected by increasing vital rate variability relative to longer-lived species (perennial plants, birds, ungulates). Taxonomic affiliation has little power to explain sensitivity to increasing variability once longevity has been taken into account. Our results highlight the potential vulnerability of short-lived species to an increasingly variable climate, but also suggest that problems associated with short-lived undesirable species (agricultural pests, disease vectors, invasive weedy plants) may be exacerbated in regions where climate variability decreases.     

Sex-specific reproductive behaviours and paternity in free-ranging Barbary macaques (Macaca sylvanus)

In a wide variety of species, male reproductive success is determined by contest for access to females. Among multi-male primate groups, however, factors in addition to male competitive ability may also influence paternity outcome, although their exact nature and force is still largely unclear. Here, we have investigated in a group of free-ranging Barbary macaques whether paternity is determined on the pre- or postcopulatory level and how male competitive ability and female direct mate choice during the female fertile phase are related to male reproductive success. Behavioural observations were combined with faecal hormone analysis for timing of the fertile phase (13 cycles, 8 females) and genetic paternity analysis (n = 12). During the fertile phase, complete monopolisation of females did not occur. Females were consorted for only 49% of observation time, and all females had ejaculatory copulations with several males. Thus, in all cases, paternity was determined on the postcopulatory level. More than 80% of infants were sired by high-ranking males, and this reproductive skew was related to both, male competitive ability and female direct mate choice as high-ranking males spent more time in consort with females than low-ranking males, and females solicited copulations mainly from dominant males. As most ejaculatory copulations were female-initiated, female direct mate choice appeared to have the highest impact on male reproductive success. However, female preference was not directly translated into paternity, as fathers were not preferred over non-fathers in terms of solicitation, consortship and mating behaviour. Collectively, our data show that in the Barbary macaque, both sexes significantly influence male mating success, but that sperm of several males generally compete within the female reproductive tract and that therefore paternity is determined by mechanisms operating at the postcopulatory level.     

Global status of and prospects for protection of terrestrial geophysical diversity

Conservation of representative facets of geophysical diversity may help conserve biological diversity as the climate changes. We conducted a global classification of terrestrial geophysical diversity and analyzed how land protection varies across geophysical diversity types. Geophysical diversity was classified in terms of soil type, elevation, and biogeographic realm and then compared to the global distribution of protected areas in 2012. We found that 300 (45%) of 672 broad geophysical diversity types currently meet the Convention on Biological Diversity's Aichi Target 11 of 17% terrestrial areal protection, which suggested that efforts to implement geophysical diversity conservation have a substantive basis on which to build. However, current protected areas were heavily biased toward high elevation and low fertility soils. We assessed 3 scenarios of protected area expansion and found that protection focused on threatened species, if fully implemented, would also protect an additional 29% of geophysical diversity types, ecoregional‐focused protection would protect an additional 24%, and a combined scenario would protect an additional 42%. Future efforts need to specifically target low‐elevation sites with productive soils for protection and manage for connectivity among geophysical diversity types. These efforts may be hampered by the sheer number of geophysical diversity facets that the world contains, which makes clear target setting and prioritization an important next step.