Detection of hepatotoxic Microcystis strains by PCR with intact cells from both culture and environmental samples

Microcystins are small hepatotoxic peptides produced by a number of cyanobacteria. They are synthesized non-ribosomally by multifunctional enzyme complex synthetases encoded by the mcy genes. Primers deduced from mcy genes were designed to discriminate between toxic microcystin-producing strains and non-toxic strains. Thus, PCR-mediated detection of mcy genes could be a simple and efficient means to identify potentially harmful genotypes among cyanobacterial populations in bodies of water. We surveyed the distribution of the mcyB gene in different Microcystis strains isolated from Chinese bodies of water and confirmed that PCR can be reliably used to identify toxic strains. By omitting any DNA purification steps, the modified PCR protocol can greatly simplify the process. Cyanobacterial cells enriched from cultures, field samples, or even sediment samples could be used in the PCR assay. This method proved sensitive enough to detect mcyB genes in samples with less than 2,000 Microcystis cells per ml. Its accuracy, specificity and applicability were confirmed by sequencing selected DNA amplicons, as well as by HPLC, ELISA and mouse bioassay as controls for toxin production of every strain used.

Seasonal ITCZ migration dynamically controls the location of the (sub)tropical Atlantic biogeochemical divide

Inorganic nitrogen depletion restricts productivity in much of the low-latitude oceans, generating a selective advantage for diazotrophic organisms capable of fixing atmospheric dinitrogen (N2). However, the abundance and activity of diazotrophs can in turn be controlled by the availability of other potentially limiting nutrients, including phosphorus (P) and iron (Fe). Here we present high-resolution data (∼0.3°) for dissolved iron, aluminum, and inorganic phosphorus that confirm the existence of a sharp north–south biogeochemical boundary in the surface nutrient concentrations of the (sub)tropical Atlantic Ocean. Combining satellite-based precipitation data with results from a previous study, we here demonstrate that wet deposition in the region of the intertropical convergence zone acts as the major dissolved iron source to surface waters. Moreover, corresponding observations of N2 fixation and the distribution of diazotrophic Trichodesmium spp. indicate that movement in the region of elevated dissolved iron as a result of the seasonal migration of the intertropical convergence zone drives a shift in the latitudinal distribution of diazotrophy and corresponding dissolved inorganic phosphorus depletion. These conclusions are consistent with the results of an idealized numerical model of the system. The boundary between the distinct biogeochemical systems of the (sub)tropical Atlantic thus appears to be defined by the diazotrophic response to spatial–temporal variability in external Fe inputs. Consequently, in addition to demonstrating a unique seasonal cycle forced by atmospheric nutrient inputs, we suggest that the underlying biogeochemical mechanisms would likely characterize the response of oligotrophic systems to altered environmental forcing over longer timescales.

Maternal care in the rockpool amphipod Apherusa jurinei: developmental and environmental cues

There is evidence that active, pre-emergence maternal brood care in amphipod crustaceans may be associated with 'harsh' environmental conditions. We examined, in the rockpool amphipod Apherusa jurinei, behavioural activities that may function as a form of active brood care. Only ovigerous females showed 'curl' and 'stretch' activities, with consequent flushing of the brood pouch and cycling of the eggs therein. There was a significant decline in these activities as embryonic development advanced and brood care almost ceased when well-developed embryos showed a heart pulse and self-ventilation. We propose that this pattern of brood care reflects changes in the physiological requirements of embryos as they develop within the egg membrane. In addition, ovigerous females showed significantly higher levels of brood care under lowered oxygen conditions. They achieved this by increasing the average duration of the 'stretch' component, with other brood care components remaining constant. Thus, developmental and environmental cues alter the components of active brood care in distinct ways. Experimental removal showed that the physical presence of eggs in the brood pouch is important in controlling the expression of brood care activities. However, females with all of their eggs removed continued to brood at low levels, suggesting that a maternal state also controls brood care. The sophisticated expression of active maternal brood care in amphipods under 'harsh' environmental conditions such as rockpools has implications both for individual reproductive success and the distribution and abundance of brooding versus nonbrooding species. (C) 2002 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

Controls on the contemporary distribution of lake thecamoebians (testate amoebae) in the Greater Toronto Area and their potential as water quality indicators.

Thecamoebians were examined from 71 surface sediment samples collected from 21 lakes and ponds in the Greater Toronto Area to (1) elucidate the controls on faunal distribution in modern lake environments; and (2) to consider the utility of thecamoebians in quantitative studies of water quality change. This area was chosen because it includes a high density of kettle and other lakes which are threatened by urban development and where water quality has deteriorated locally as a result of contaminant inputs, particularly nutrients. Fifty-eight samples yielded statistically significant thecamoebian populations. The most diverse faunas (highest Shannon Diversity Index values) were recorded in lakes beyond the limits of urban development, although the faunas of all lakes showed signs of sub-optimal conditions. The assemblages were divided into five clusters using Q-mode cluster analysis, supported by Detrended Correspondence Analysis. Canonical Correspondence Analysis (CCA) was used to examine species-environment relationships and to explain the observed clusterings. Twenty-four measured environmental variables were considered, including water property attributes (e.g., pH, conductivity, dissolved oxygen), substrate characteristics, sediment-based phosphorus (Olsen P) and 11 environmentally available metals. The thecamoebian assemblages showed a strong association with phosphorus, reflecting the eutrophic status of many of the lakes, and locally to elevated conductivity measurements, which appear to reflect road salt inputs associated with winter de-icing operations. Substrate characteristics, total organic carbon and metal contaminants (particularly Cu and Mg) also influenced the faunas of some samples. A series of partial CCAs show that of the measured variables, sedimentary phosphorus has the largest influence on assemblage distribution, explaining 6.98% (P < 0.002) of the total variance. A transfer function was developed for sedimentary phosphorus (Olsen P) using 58 samples from 15 of the studied lakes. The best performing model was based on weighted averaging with inverse deshrinking (WA Inv, r jack 2= 0.33, RMSEP = 102.65 ppm). This model was applied to a small modern thecamoebian dataset from a eutrophic lake in northern Ontario to predict phosphorus and performed satisfactorily. This preliminary study confirms that thecamoebians have considerable potential as quantitative water quality indicators in urbanising regions, particularly in areas influenced by nutrient inputs and road salts.

Controls on stone temperatures and the benefits of interdisciplinary exchange

Data derived from a series of field and laboratory studies of the influence of albedo and thermal conductivity on stone temperatures are reported. They indicate the complexity of surface/subsurface temperature response characteristics of different stone types exposed to the same conditions and highlight the influence of albedo and thermal conductivity on micro-environmental conditions at the rock/air interface – conditions which have significant implications for the nature and rate of weathering activity and which may, over time, affect any surface treatments applied to stone surfaces. Although the studies reviewed were carried out within the subject area of geomorphology, the data reported and the implications for stone weathering arising from them, may be of some relevance to the conservation science perspective on deterioration of contemporary, historical and archaeological stonework.

Electric vehicles and opportunities to displace tailgate emissions using Smart Charging controls

Under the European Union Renewable Energy Directive each Member State is mandated to ensure that 10% of transport energy (excluding aviation and marine transport) comes from renewable sources by 2020. The Irish Government intends to achieve this target with a number of policies including ensuring that 10% of all vehicles in the transport fleet are powered by electricity by 2020. This paper investigates the impact of the 10% electric vehicle target in Ireland in 2020 using a dynamic programming based long term generation expansion planning model. The model developed optimizes power dispatch using hourly electricity demand curves up to 2020, while incorporating generator characteristics and certain operational requirements such as energy not served and loss of load probability while satisfying constraints on environmental emissions, fuel availability and generator operational and maintenance costs. Two distinct scenarios are analysed based on a peak and off-peak charging regimes in order to simulate the effects of the electric vehicles charging in 2020. The importance and influence of the charging regimes on the amount of energy used and tailgate emissions displaced is then determined.

Climatic patterns and physical controls of chlorophyll-a in the Northeast Atlantic

Tese de Doutoramento, Física, 17 de Dezembro de 2013, Universidade dos Açores.

Paper industry in Kerala: An evaluation of labour absorption,capacity utilisation, and environmental pollution

Paper industry is one of the oldest and largest industries in Kerala. Despite the developments in the industry in terms of growth in output , value added and employment generation, many of the units face grave problems. Irrespective of the size of the plant, the problems of the industry are general in nature. The problems are galore in the supply, not the demand side. Amomg the problems, the important ones are: raw material scarcity, energy deficiency and obsolete technology. Further, the industry is subject to many controls by the Government — price control, product control and raw materials control — which result in the dwindling of profits and investments. Equally important are the reservations against the industry for polluting the environment byeffluent disposal on the one hand and affecting ecological balance by depleting the existing forest on the other. Apart from the large, medium and small pulp and paper mills, there are about 30 hand made paper units in Kerala which can be categorised as village and cottage industry. Almost all of these units began at the initiative and support of Khadi and Village Industries Commission. The primary purpose of these units is employment generation, and not profit making. Currently many of these units are in the red and many others are on the verge of closure. Therefore, a separate analysis of the growth performance, and problems and prospects of the hand made paper industry has also been attempted. It is analysed separately because of the very small size of the hand made paper units

Land Use Controls with Special Reference to Wetlands

This is a study of land use law in India. Land use Controls has been a subject of controversy since the human settlement. Gamut of control increased with human development. Now the controls are for many purposes.Nuisance created through various land use was tried to be avoidedthrough the common law controls7. Whether the utility of the activity outweighs the environmental consideration was the consideration before the court. A standard definition8 of nuisance could meet most of the problems relating to land use. Later on, planning and zoning laws brought in major changes. Health, safety and facilities of others attracted land use controls9. After the Stockholm the sphere of government interference increased. Several legislations were enacted. Existing legislations were modified. These come in conflict with the interests of different sections of society. Coastal Regulations10 and high range protection11 are manifestations of such unrest. A systematic study on these issues is of current interest. Exploring of some areas in this respect is also relevant in this respect.

Controls on development and diversity of Early Archean stromatolites

The ≈3,450-million-year-old Strelley Pool Formation in Western Australia contains a reef-like assembly of laminated sedimentary accretion structures (stromatolites) that have macroscale characteristics suggestive of biological influence. However, direct microscale evidence of biology—namely, organic microbial remains or biosedimentary fabrics—has to date eluded discovery in the extensively-recrystallized rocks. Recently-identified outcrops with relatively good textural preservation record microscale evidence of primary sedimentary processes, including some that indicate probable microbial mat formation. Furthermore, we find relict fabrics and organic layers that covary with stromatolite morphology, linking morphologic diversity to changes in sedimentation, seafloor mineral precipitation, and inferred microbial mat development. Thus, the most direct and compelling signatures of life in the Strelley Pool Formation are those observed at the microscopic scale. By examining spatiotemporal changes in microscale characteristics it is possible not only to recognize the presence of probable microbial mats during stromatolite development, but also to infer aspects of the biological inputs to stromatolite morphogenesis. The persistence of an inferred biological signal through changing environmental circumstances and stromatolite types indicates that benthic microbial populations adapted to shifting environmental conditions in early oceans.

Floodplain environmental change during the Younger Dryas and Holocene in Northwest Europe: Insights from the lower Kennet Valley, south central England

Many lowland rivers across northwest Europe exhibit broadly similar behavioural responses to glacial-interglacial transitions and landscape development. Difficulties exist in assessing these, largely because the evidence from many rivers remains limited and fragmentary. Here we address this issue in the context of the river Kennet, a tributary of the Thames, since c. 13,000 cal BP. Some similarities with other rivers are present, suggesting that regional climatic shifts are important controls. The Kennet differs from the regional pattern in a number of ways. The rate of response to sudden climatic change, particularly at the start of the Holocene and also mid-Holocene forest clearance, appears very high. This may reflect abrupt shifts between two catchment scale hydrological states arising from contemporary climates, land use change and geology. Stadial hydrology is dominated by nival regimes, with limited winter infiltration and high spring and summer runoff. Under an interglacial climate, infiltration is more significant. The probable absence of permafrost in the catchment means that a lag between the two states due to its gradual decay is unlikely. Palaeoecology, supported by radiocarbon dates, suggests that, at the very start of the Holocene, a dramatic episode of fine sediment deposition across most of the valley floor occurred, lasting 500-1000 years. A phase of peat accumulation followed as mineral sediment supply declined. A further shift led to tufa deposition, initially in small pools, then across the whole floodplain area, with the river flowing through channels cut in tufa and experiencing repeated avulsion. Major floods, leaving large gravel bars that still form positive relief features on the floodplain, followed mid-Holocene floodplain stability. Prehistoric deforestation is likely to be the cause of this flooding, inducing a major environmental shift with significantly increased surface runoff. Since the Bronze Age, predominantly fine sediments were deposited along the valley with apparently stable channels and vertical floodplain accretion associated with soil erosion and less catastrophic flooding. The Kennet demonstrates that, while a general pattern of river behaviour over time, within a region, may be identifiable, individual rivers are likely to diverge from this. Consequently, it is essential to understand catchment controls, particularly the relative significance of surface and subsurface hydrology. (c) 2005 Elsevier B.V. All rights reserved.

Sediment fingerprinting as an environmental forensics tool explaining cyanobacteria blooms in lakes

Cyanobacteria (blue-green algae) blooms in water bodies present serious public health issues with attendant economic and ecological impacts. Llyn Tegid (Lake Bala) is an important conservation and amenity asset within Snowdonia National Park, Wales which since the mid-1990s has experienced multiple toxic cyanobacteria blooms threatening the ecology and tourism-dependent local economy. Multiple working hypotheses explain the emergence of this problem, including climate change, land management linked to increased nutrient flux, hydromorphological alterations or changing trophic structure - any of which may operate individually or cumulatively to impair lake function. This paper reports the findings of a sedimentfingerprinting study using dated lake cores to explore the linkages between catchment and lake management practices and the emergence of the algal blooms problem. Since 1900 AD lake bed sedimentation rates have varied from 0.06 to 1.07 g cm−2 yr−1, with a pronounced acceleration since the early 1980s. Geochemical analysis revealed increases in the concentrations of total phosphorus (TP), calcium and heavy metals such as zinc and lead consistent with eutrophication and a rising pollution burden, particularly since the late 1970s. An uncertainty-inclusive sedimentfingerprinting approach was used to apportion the relative fluxes from the major catchment land cover types of improved pasture, rough grazing, forestry and channel banks. This showed improved pasture and channel banks are the dominant diffuse sources of sediment in the catchment, though forestry sources were important historically. Conversion of rough grazing to improved grassland, coupled with intensified land management and year-round livestock grazing, is concluded to provide the principal source of rising TP levels. Lake Habitat Survey and particle size analysis of lake cores demonstrate the hydromorphological impact of the River Dee Regulation Scheme, which controls water level and periodically diverts flow into Llyn Tegid from the adjacent Afon Tryweryn catchment. This hydromorphological impact has also been most pronounced since the late 1970s. It is concluded that an integrated approach combining land management to reduce agricultural runoff allied to improved water level regulation enabling recovery of littoral macrophytes offers the greatest chance halting the on-going cyanobacteria issue in Llyn Tegid.

Pedosedimentary, cultural and environmental significance of palaeosols within Pre-Hispanic agricultural terraces in the southern Peruvian Andes

Paleosols were exposed in sections through four abandoned pre-Hispanic agricultural terraces surrounding an infilled mire basin in the southern Peruvian Andes. The two paleosols beneath the Tocotoccasa terrace represent the original ‘natural’ solum and a later soil formed after construction of the agricultural terrace, probably during the early Middle Horizon cultural period (615–695 AD). The soil at the current surface developed subsequent to the building up and reconstruction of the terrace, possibly during the late Late Intermediate period (1200–1400 AD). Micromorphology revealed an unexpected abundance of clay coatings within the upper terrace paleosol and surface terrace soil, a phenonemon attributed to the migration and/or accumulation of neoformed clay produced from the weathering of very unstable volcanic clasts, perhaps fuelled by arid/humid climatic oscillations and/or seasonal input of irrigation waters. The paleosols at Tocotoccasa could not be correlated with any degree of confidence with those beneath the other three terraces due to differences in pedosedimentary properties and uncertainties over chronological controls. Thus, it seems likely that either the terraces were (re)constructed and utilised over different cultural periods or that there is significant variation in the extent of weathering of material used for reconstruction of the terraces. Unfortunately, it cannot be ascertained from the data available whether the terraces were abandoned for any significant period of time prior to reconstruction and, if so, whether this was a regional phenomenon related to climate, social, or economic changes.

Riparian shading controls instream spring phytoplankton and benthic diatom growth

Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually supressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade.

Atmospheric versus vegetation controls of Amazonian tropical rain forest evapotranspiration: Are the wet and seasonally dry rain forests any different?

This study analyzes evapotranspiration data for three wet and two seasonally dry rain forest sites in Amazonia. The main environmental (net radiation, vapor pressure deficit, and aerodynamic conductance) and vegetation (surface conductance) controls of evapotranspiration are also assessed. Our research supports earlier studies that demonstrate that evapotranspiration in the dry season is higher than that in the wet season and that surface net radiation is the main controller of evapotranspiration in wet equatorial sites. However, our analyses also indicate that there are different factors controlling the seasonality of evapotranspiration in wet equatorial rain forest sites and southern seasonally dry rain forests. While the seasonality of evapotranspiration in wet equatorial forests is driven solely by environmental factors, in seasonally dry forests, it is also biotically controlled with the surface conductance varying between seasons by a factor of approximately 2. The identification of these different drivers of evapotranspiration is a major step forward in our understanding of the water dynamics of tropical forests and has significant implications for the future development of vegetation-atmosphere models and land use and conservation planning in the region.