Impacts of climate variability and human colonization on the vegetation of the Galápagos Islands

A high-resolution (2-9 year sampling interval) fossil pollen record from the Galápagos Islands, which spans the last 2690 years, reveals considerable ecosystem stability. Vegetation changes associated with independently derived histories of El Ni?o Southern Oscillation variability provided evidence of shifts in the relative abundance of individual species rather than immigration or extinction. Droughts associated with the Medieval Climate Anomaly induced rapid ecological change that was followed by a reversion to the previous state. The paleoecological data suggested nonneutral responses to climatic forcing in this ecosystem prior to the period of human influence. Human impacts on the islands are evident in the record. A marked decline in long-term codominants of the pollen record, Alternanthera and Acalypha, produced a flora without modern analogue before 1930. Intensified animal husbandry after ca. 1930 may have induced the local extinction of Acalypha and Alternanthera. Reductions in populations of grazing animals in the 1970s and 1980s did not result in the return of the native flora, but in invasions by exotic species. After ca. 1970 the trajectory of habitat change accelerated, continuously moving the ecosystem away from the observed range of variability in the previous 2690 years toward a novel ecosystem. The last 40 years of the record also suggest unprecedented transport of lowland pollen to the uplands, consistent with intensified convection and warmer wet seasons.     

Evolution, radiation and chemotaxonomy of Lamellodysidea, a demosponge genus with anti-plasmodial metabolites

Sponges of the family Dysideidae (Dictyoceratida) are renowned for their diversity of secondary metabolites, and its genus Lamellodysidea, particularly Lamellodysidea herbacea, is the most studied taxon biochemically. Despite its importance, the taxonomic status of L. herbacea—whether it is a distinct species or a species complex—has never been assessed. Recent biochemical profiling revealed anti-plasmodial activity of brominated compounds in Lamellodysidea of the Pacific. Here, we present a comparative chemotaxonomic and molecular analysis of selected Dysideidae from the Pacific and the Indian Ocean (New Caledonia, Great Barrier Reef, Fiji, Mayotte, Guam, Palau). We investigated the phylogenetic relationships between the populations and assessed their bioactive (PBDE) compounds in order to unravel the taxonomic status of this commercially important group of sponges and assessed patterns of dispersal and biochemical variation. The molecular phylogeny was based on the internal transcribed ribosomal spacer and compared against a PBDE phylogeny for several specimens. Molecular data revealed a diversity of Indo-Pacific L. herbacea populations, also reflected by different PBDE compound profiles. Molecular and biochemical data also revealed a Lamellodysidea species new to science. Several specimens misidentified as Lamellodysidea were detected based on their position on different clades in the molecular phylogeny and their production of different halogenated compounds (brominated vs. chlorinated). The direct comparison of molecular and biochemical data also provided evidence for the occurrence of a host switch event and support for the theory that abiotic factors, such as sedimentation, affect the chemical constituents produced in L. herbacea.     

Mitochondrial DNA phylogeography of the harbour porpoise Phocoena phocoena in the North Pacific

Genetic structure and phylogeography of the harbour porpoise Phocoena phocoena in the North Pacific were examined using 358 bps sequences from the 5′ end of the mitochondrial DNA control region including those reported previously and newly obtained from the west Pacific. AMOVA and pairwise population φ _st estimates clearly revealed genetic differentiation between an east/south and a north/northwest group with the break along the Pacific Rim at British Columbia. In addition, nested clade phylogeographical analysis, neutrality tests, mismatch distribution analysis, genetic diversities and Mantel test, suggested that the observed genetic structure might have been influenced by contiguous range expansion with restricted gene flow in the direction from south to north along the North American coasts and east to west along the Pacific Rim in the middle to late Pleistocene.     

Analysis of time-scaling properties in forest-fire sequence observed in Italy

The investigation of the temporal fluctuations in forest fires is an important topic in the context of environmental sciences. Time-scaling scale-invariant methodologies have been used to characterize the temporal properties of forest-fire sequences detected in the Italian territory. Our findings reveal that the fire sequences can be considered as fractal processes with a high degree of time-clusterization of the events. The time-clustering phenomenon is clearly visible from timescales of order of days. Furthermore the fire sequences observed with decreasing latitude tend to be more time-clusterized.     

A new integrated treatment for the reduction of organic and nitrogen loads in methanogenic landfill leachates

Because of their high organic and nitrogen loads and the presence of toxic and phytotoxic compounds, methanogenic landfill leachates are not easily biodegradable; therefore, direct biological treatment of these wastewaters in conventional treatment plants is not recommended.In the present paper, we report the results of an experimental investigation conducted with the aim of defining an innovative integrated process that is low in cost and easily manageable and that is able to substantially improve the characteristics of methanogenic leachates.Thus, an initial oxidation process was developed using hydrogen peroxide without a catalyst, which, operating under ambient conditions, reduces the phytotoxic compound content to 10% of the initial level, reduces the COD (chemical oxygen demand) content by 50% and increases the rapidly biodegradable substrate content by 50%. Next, nitrogen removal is accomplished by means of struvite precipitation using seawater bittern and bone meal as sources of magnesium and phosphorus, respectively, with this process, abatements were reached of approximately 90% of the ammonia nitrogen, which was recovered as struvite powder.     

A protracted age of oil: pipelines,refineries and quiet conflict

This article examines the relevance of environmental justice (EJ) and climate change debates as points of articulation and mobilisation among community groups responding to a proposed refinery. It then compares media coverage of the refinery project, a bi-national pipeline and other energy and climate-related news events. The analytical frame joins the EJ paradigm with citizen mobilisation on issues of climate change and energy projects that emit greenhouse gases and that discourage development of renewable sources. Data were collected and analysed from websites, public message boards and media documents. Findings indicate that a community-based anti-refinery campaign combined local EJ struggles with climate activism, while challenging fossil fuel dependencies and calling for renewable regional energy. A climate justice community formed – yet their voices were in their blogs and websites, not in local or national media.     

阴离子粘土(LDH)吸附腐殖酸的动力学研究

利用实验室制备的镁铝阴离子粘土材料,研究其吸附水中腐殖酸的动力学.研究结果表明:在初始浓度10～40 mg/L及温度298～323 K的范围内,阴离子粘土对水中腐殖酸的吸附动力学符合拟二级速率方程;阴离子粘土对腐殖酸的吸附符合Langmuir和Freundlich等温吸附方程,吸附是吸热反应,吸附量随温度升高而略有增加,但吸附表观活化能只有15.36 kJ/mol,说明温度对此吸附的影响并不显著.     

The ability of a benthic elasmobranch to discriminate between biological and artificial electric fields

To investigate the ability of elasmobranchs to distinguish between differing prey-type electric fields we examined the electroreceptive foraging behaviour of a model species, Scyliorhinus canicula (small-spotted catshark). Catshark preferences were studied by behaviourally conditioning them to swim through narrow tunnels, and on exit presenting them simultaneously with two different electric fields. Their subsequent choices of the following paired options were recorded; (i) Two artificial electric fields (dipole electrodes) with different magnitude direct current (D.C.), (ii) Two artificial electric fields, one D.C. and the other alternating current (A.C.), of the same magnitude, and (iii) similar magnitude, natural and artificial D.C. electric fields associated with shore crabs and dipole electrodes respectively. We found a highly significant preference for the stronger D.C. electric field and a less pronounced, but still significant, preference for the A.C. electric field rather than the D.C. electric field. No preference was demonstrated between the artificial and natural D.C. electric fields. The findings are discussed in relation to the animal’s diet and ecology and with regard to anthropogenic sources of electric fields within their habitat.     

The development of probabilistic models to estimate accident risk (due to runway overrun and landing undershoot) applicable to the design and construction of runway safety areas

The risks of landing overrun (LDOR – LanDing OverRun), Take-off Overrun (TOOR – Take-Off OverRun) and landing undershoot (LDUS – LanDing UnderShoot) are dependent on multiple factors related to operating conditions. These include wind, runway surface conditions, landing or take-off distances required, the presence of obstacles, runway distance available, the existence and dimensions of runway safety areas.In this paper we propose risk models for runway overrun and landing undershoot, using a probabilistic approach. These models are supported by historical data on accidents in the area around the runway and will enable us to determine if the risk level is acceptable or whether action must be taken to mitigate such risks at a given airport. Furthermore, these models permit comparison of the results of different risk mitigation actions in terms of operational risk and safety.The principal advantage of this method is the high quality results obtained for a limited investment in terms of time, computing power and data. As such the method is extremely practical and easy to apply in aerodrome planning, development and operation.     

Advanced REACH Tool (ART): calibration of the mechanistic model

The mechanistic model of the Advanced Reach Tool (ART) provides a relative ranking of exposure levels from different scenarios. The objectives of the calibration described in this paper are threefold: to study whether the mechanistic model scores are accurately ranked in relation to exposure measurements; to enable the mechanistic model to estimate actual exposure levels rather than relative scores; and to provide a method of quantifying model uncertainty. Stringent data quality guidelines were applied to the collated data. Linear mixed effects models were used to evaluate the association between relative ART model scores and measurements. A random scenario and company component of variance were introduced to reflect the model uncertainty. Stratified analyses were conducted for different forms of exposure (abrasive dust, dust, vapours and mists). In total more than 2000 good quality measurements were available for the calibration of the mechanistic model. The calibration showed that after calibration the mechanistic model of ART was able to estimate geometric mean (GM) exposure levels with 90% confidence for a given scenario to lie within a factor between two and six of the measured GM depending upon the form of exposure.