Earth Sciences

By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification.

Woody invading alien plants, many of which are nitrogen-fixing legumes (Fabaceae family), are currently cleared in South African catchments to reduce water loss and preserve streamflow, and for the restoration of the ecosystem. This study tested the hypothesis that clearing invasive alien vegetation may disturb the vegetation-micro-organism-soil N cycling system by producing a large once-off input of fresh tree litterfall rich in N and by eliminating a large N sink. Three experimental plots were established at the Riverlands Nature Reserve (Western Cape, South Africa): a site invaded by Acacia saligna to be used as control; a site cleared of Acacia saligna; and a site with natural vegetation to be used as background. Nitrogen concentrations in soil and groundwater, volumetric soil water contents, root density and weather conditions were measured during 2007. Oxidised forms of nitrogen, in particular NO 3 -, were dominant in the system. Recharge and leachate were simulated with the HYDRUS-2D model and used as inputs into Visual MODFLOW to predict the spatial distribution of nitrate plus nitrite (NOx) in groundwater. NOx levels in soil and groundwater were higher in alien-invaded areas compared to fynbos-covered land. A quick release of NOx into groundwater was observed due to high residual N reserves in the rooting zone, decreased evapotranspiration and increased recharge in the treatment cleared of alien vegetation. In the long run, high NOx concentrations in groundwater underlying cleared land will last only until all the excess nitrogen has been leached from the soil. A decrease in NOx concentration in groundwater can be expected thereafter. Clearing land of alien invasive legumes may therefore have a beneficial effect by reducing groundwater contamination from NOx and reducing water losses in catchments.

The Atlantis Water Supply Scheme (AWSS, Western Cape, South Africa) has been in operation for about 40 years as a means to supply and augment drinking water to the town of Atlantis via managed aquifer recharge (MAR). In this study, the numerical model MODFLOW for groundwater flow and contaminant transport was used in support of the management of the AWSS. The aims were: (i) to calibrate the MODFLOW model for the MAR site at Atlantis; (ii) to run realistic scenarios that cannot be replicated through experiments; and (iii) to make recommendations in support of efficient and sustainable management of the aquifer. MODFLOW was calibrated through comparison of observed and simulated groundwater levels (R 2 between 0.663 and 0.995). Scenario simulations indicated possible drawdowns between < 5 m (low groundwater abstraction and low artificial recharge of groundwater through infiltration basins) and > 20 m (high abstraction and high artificial recharge) at localized areas of the Witzand wellfield. At Silwerstroom, large drawdown levels were not predicted to occur, so this wellfield could be exploited more without affecting the sustainability of the groundwater resource. Groundwater moves from the infiltration basins towards the Witzand wellfield at a rate of 120-150 m•a -1 . The modelling results supported recommendations for balancing groundwater abstraction and artificial recharge volumes, monitoring the water balance components of the system, the potential risks of groundwater contamination and the delineation of groundwater protection zones.

The primary aquifer at Atlantis (Western Cape, South Africa) is ideally suited for water supply and the indirect recycling of urban stormwater runoff and treated domestic wastewater for potable purposes. The relatively thin, sloping aquifer requires careful management of the artificial recharge and abstraction for balancing water levels. Water quality management is a further key issue at Atlantis for ensuring the highest quality potable water. Groundwater quality varies from point to point in the aquifer, while urban runoff and wastewater qualities vary greatly. The layout of the town allows for the separation of stormwater from the residential and industrial areas as well as separate treatment of domestic and industrial wastewater. This permits safe artificial recharge of the various water quality portions at different points in the aquifer, either for recycling or for preventing seawater intrusion. All of the management actions are dependent on detailed data collection and this paper describes the various parts of the system, describes the data collection activities, and provides results of the monitoring and aquifer responses over the past four decades. Challenges related to iron fouling of production boreholes are also described. The presence of emerging contaminants was studied in 2008 but requires follow-up research for establishing the extent of any possible threat to water recycling. In order to address the shortcomings of the system a risk management plan based on the Hazard Analysis and Critical Control Points approach was developed. Lessons learnt from the Atlantis experience can be transferred to other potential sites for establishment of similar systems in arid and semi-arid areas of South Africa and the African continent.

The Mobius model building system is a new opensource framework for building fast and flexible environmental models. Mobius makes it possible for researchers with limited programming experience to build performant models with potentially complicated structures. Mobius models can be easily interacted with through the MobiView graphical user interface and through the Python programming language. Mobius was initially developed to support catchmentscale hydrology and water-quality modelling but can be used to represent any system of hierarchically structured ordinary differential equations, such as population dynamics or toxicological models. Here, we demonstrate how Mobius can be used to quickly prototype several different model structures for a dissolved organic carbon catchment model and use built-in auto-calibration and statistical uncertainty analysis tools to help decide on the best model structures. Overall, we hope the modular model building platform offered by Mobius will provide a step forward for environmental modelling, providing an alternative to the "one size fits all" modelling paradigm. By making it easier to explore a broader range of model structures and parameterisations, users are encouraged to build more appropriate models, and in turn this improves process understanding and allows for more robust modelling in support of decision making.

Two sediment cores retrieved at the northern slope of Sakhalin Island, Sea of Okhotsk, were analyzed for biogenic opal, organic carbon, carbonate, sulfur, major element concentrations, mineral contents, and dissolved substances including nutrients, sulfate, methane, major cations, humic substances, and total alkalinity. Down-core trends in mineral abundance suggest that plagioclase feldspars and other reactive silicate phases (olivine, pyroxene, volcanic ash) are transformed into smectite in the methanogenic sediment sections. The element ratios Na/Al, Mg/Al, and Ca/Al in the solid phase decrease with sediment depth indicating a loss of mobile cations with depth and producing a significant down-core increase in the chemical index of alteration. Pore waters separated from the sediment cores are highly enriched in dissolved magnesium, total alkalinity, humic substances, and boron. The high contents of dissolved organic carbon in the deeper methanogenic sediment sections (50-150 mg dm À3 ) may promote the dissolution of silicate phases through complexation of Al 3+ and other structure-building cations. A non-steady state transport-reaction model was developed and applied to evaluate the down-core trends observed in the solid and dissolved phases. Dissolved Mg and total alkalinity were used to track the in-situ rates of marine silicate weathering since thermodynamic equilibrium calculations showed that these tracers are not affected by ion exchange processes with sediment surfaces. The modeling showed that silicate weathering is limited to the deeper methanogenic sediment section whereas reverse weathering was the dominant process in the overlying surface sediments. Depth-integrated rates of marine silicate weathering in methanogenic sediments derived from the model (81.4-99.2 mmol CO 2 m À2 year À1 ) are lower than the marine weathering rates calculated from the solid phase data (198-245 mmol CO 2 m À2 year À1 ) suggesting a decrease in marine weathering over time. The production of CO 2 through reverse weathering in surface sediments (4.22-15.0 mmol CO 2 m À2 year À1 ) is about one order of magnitude smaller than the weathering-induced CO 2 consumption in the underlying sediments. The evaluation of pore water data from other continental margin sites shows that silicate weathering is a common process in methanogenic sediments. The global rate of CO 2 consumption through marine silicate weathering estimated here as 5-20 Tmol CO 2 year À1 is as high as the global rate of continental silicate weathering.

A stratigraphic framework valid for the Pliocene-Middle Pleistocene continental deposits of the Latium-Abruzzi Apennines has been defined through the correlation of the depositional/erosional events (indicated by stratigraphic and morphologic units, respectively) across seven different intermontane basins. This has been made by comparing the geological evolutions of the different basins. The basic assumption for the correlation of the different events is that climatic factors have conditioned the geological evolution of the investigated sector in a substantially uniform way. Uniform climatic conditions have caused similar responses of the basins to the climatic changes. Continental deposition in the Latium-Abruzzi Apennines began during the Pliocene, prevalently with clayey-silty-sandy lacustrine deposits fed by the clayey-arenaceous flysch into which the landscape was carved at the time of the first continental deposition. The formation of an indented landscape with higher slopes bordering the basins is demonstrated by huge landslide deposits of both arenaceous and calcareous coarse material. Sediments related to the second depositional event (Early Pleistocene) are mainly characterised by a carbonate lithology in slope deposits (slope-derived breccias), in lacustrine (carbonate silts) and fluvial (carbonate gravels) sediments. This is due to the dominant carbonate lithology of the bedrock in the areas experiencing erosion during the Quaternary. The third depositional event (related to the lower Middle Pleistocene) has lithological and sedimentological characteristics comparable to those of the second event. It consists, indeed, of slope-derived carbonate breccias, carbonate silty deposits of lacustrine origin and carbonate gravels of fluvial facies. The fourth depositional event (Middle Pleistocene) is characterised by the first significant deposition of material of volcanic origin and numerous tephra levels related to the central Italy volcanic activity can be detected. Chronological constraints for the second depositional event are represented by the reverse paleomagnetic polarity of the deposits, defining ages older than 0.78 Ma and by the remains of Arkidiscon meridionalis vestinus Azzaroli in the L'Aquila basin. Chronological data for the third depositional event are represented by paleontological remains of Equus altidens Reichenau and by the association Hippopotamus antiquus Desmarest/Elephas antiquus Falc. & Cautl. and by the lack of volcanic materials which became widespread after 0.6 Ma. The age of the fourth depositional event is constrained by the presence of the tephra levels which define a deposition after about 0.6 Ma. The attribution of a Pliocene age to the deposits of the first event can only be made on a qualitative basis, since bio-chronological data or other quantitative chronological constraints are not available. In this light, the significant changes which affected the landscape between the first two depositional events seem to indicate that a very long time span passed between them. Viene proposto uno schema stratigrafico per i depositi continentli dell'Appenino laziale-abruzzese, fondato su una serie di correlazioni che riguardano le successioni riconosciute da precedenti lavori nelle principali conche intramontane. Le successioni sono uniformemente descritte in termini di unità stratigrafiche (del tipo "a limiti inconformi") e di unità morfologiche, definite come "unità morfo-sequenziali" e rappresentate da superfici relitte di erosione o di accumulo. Le correlazioni sono state ottenute mediante un confronto fra le successioni morfologico-stratigrafiche, effettuato sulla base di due presupposti: (i) che l'evoluzione geologica che le ha generate sia condizionata principalmente da fattori in vario modo ubiquitari (clima e sollevamento tettonico) e (ii) che l'interazione fra questi fenomeni si sia realizzata in un'area caratterizzata da una relativa costanza dei principali elementi idrografici. Questi presupposti inducono a ritenere che le alternanze di episodi deposizionali ed erosivi si siano sviluppate nelle diverse conche con modalità sostanzialmente simili. Le correlazioni ottenute mediante questo confronto hanno portato a definire un'unica sequenza dei principali eventi deposizionali nell'area laziale-abruzzese. L'unità stratigrafica continentale più antica è costituita prevalentemente da depositi lacustri limoso-sabbiosi provenienti quasi esclusivamente da aree costituite dalle sequenze arenaceo-argillose tortoniano-messiniane. Il paesaggio nel quale si originava l'unità era quindi molto diverso da quello attuale, dominato dalla dorsali carbonatiche. I bacini di sedimentazione erano verosimilmente caratterizzati da versanti molto acclivi, localmente interessati da imponenti fenomeni franosi che andavano ad alimentare una sedimentazione molto grossolana che si rinviene localmente intercalata ai sedimenti lacustri. Gli strati di questa prima unità stratigrafica sono spesso vistosamente deformati. Anche se non esistono elementi di diretto interesse cronologico, si può riferire l'unità ad un generico Pliocene, soprattutto sulla base dei rapporti con l'unità successiva. Questo riferimento è indirettamente avvalorato sia dalla "antichità" del paesaggio circostante, molto diverso da quello attuale, sia dalla deformazione, molto più intensa di tutte le unità successive che hanno di regola un assetto sub-orizzontale. Il successivo evento sedimentario ha dato origine a successioni di varia litologia ed ambiente (sabbie e limi lacustri, ghiaie fluviali, depositi più o meno grossolani di versante) a prevalente componente calcarea; questa caratteristica è manifestamente connessa con una alimentazione proveniente da un paesaggio che, a seguito della sempre più profonda erosione delle sequenze terrigene mioceniche, era largamente costituito dalle successioni carbonatiche mesozoiche. L'attribuzione di queste successioni al Pleistocene inferiore è giustificato dal rinvenimento, nella conca dell'Aquila, di una fauna a vertebrati pre-galeriana, contenente Mammuthus meridionalis vestinus. Congruenti con questa attribuzione sono anche alcune determinazioni di paleomagnetismo che hanno indicato una polarità inversa. Il terzo evento sedimentario ha caratteristiche abbastanza simili a quello ora descritto: se ne differenzia principalmente per la minor frequenza di episodi lacustri e per essere connesso ad una marcata tendenza all'erosione laterale che ha dato origine ad estese spianate i cui residui sono tuttora osservabili nel paesaggio. Gli unici vincoli cronologici sono rappresentati da resti di Equus altidens, rinvenuti nella conca del Fucino e di Hippopothamus antiquus e di Elephas antiquus in quella del Tirino. Questi ritrovamenti, unitamente alla mancanza di significativi apporti in materiale vulcanici, inducono ad attribuire l'unità al Pleistocene medio. Il quarto evento sedimentario è caratterizzato dalla prima comparsa di importanti apporti di materiale vulcanico che danno spesso origine a sequenze di strati tufitici: l'età è ancora meso-pleistocenica in quanto precedente ai grandi apparati fluvio-glaciali del Pleistocene superiore.

Ewaso Narok Swamp, formed along the Eng&#39;are Narok river, is located in the semi-arid part of the Laikipia District, Kenya. The area, of bushy grassland, is characterised by low rainfall (less than 750 mm annually) and episodic rivers. Before the 1970s, the dominant land use was large scale ranching and nomadic pastoralism. Since 1970, this has slowly been transformed into

The position, number and length of the setae on the cercopods of Anostraca species are graphically represented and analysed. Ali species found in Algeria are used as examples. This revealed significant differences among the representatives of the genera Artemia, Branchinella , Branchipus, Chirocephalus, Streptocephalus and Tanymastigiles , and between the related congeners Streptocephalus torvicornis and S. rubricaudatus, and Tanymastigites perrieri and T. mzab ica.

the occurrence of Lepidurus apus in Iran is reported for the first time. this species was found in Aigher goli located in the mountains area, east Azerbaijan province (North east, Iran). details on biogeography, ecology and morphology of this species are provided.

A survey on the distribution and status of large branchiopod crustaceans (Branchiopoda: Anostraca, Notostraca, Conchostraca) in Iran was carried out from spring 2008 to summer 2011 with the purpose of providing a systematic contribution to the knowledge of these crustaceans in the region. Data from literature on Iranian large branchiopods are briefly reviewed, and field surveys allowed us to add new data on their presence and co-occurrence in the area. Eleven large branchiopod species were collected, including five Anostraca, three Notostraca and three Conchostraca species. Anostraca have been recorded previously from Iran, but all of the Conchostraca (Leptestheria sp., Caenestheriella sp. and Cyzicus sp.) and Triops granarius are new records. Species richness was correlated to pool size and salinity. Diversity analysis revealed that large-size low-salinity (0.5e3 gl À1 ) pools housed more species than the other pool categories. This may suggest strong species-sorting mechanisms and possibly monopolization of resources in small saline pools. Most of the observed large branchiopod species are threatened or remain data deficient due to inadequate knowledge of their distribution. Local extinction risks are high forspecies with one or two populations due to consecutive years of drought.

Streptocephalus caljoni n . sp . from Burundi is described . It is related to Streptocephalus trifidus, but differs from it and other Streptocephalus in the cheliform hand of the male antenna II. We also analyse the morphology of the setae on the endo-and exopodite of the fifth trunk limb, using light-and scanning electron microscopy . This analysis reveals additional differences between the two related species, and is a useful tool in the study of the taxonomy of the Anostraca .

In the framework of a joint Argentine-German project gravimetric time series observations are being carried out at the Argentine Antarctic station Belgrano II. Two gravity meters were installed in the first half of February 2007. The set-up of the gravimeters as well as first results of the ongoing observations are discussed. Additionally, kinematic positions derived from a GPS-station at the Vahsel Bay glacier near Belgrano II can be used to get a first insight into the floating behavior of this glacier. The goal of these observations is to discriminate the effect of ocean tides and to test ocean tidal models. Since ocean tides are an important phenomenon that has to be considered in a variety of geoscientific investigations in polar regions, appropriate corrections have to be applied in the different analyses, e.g. to infer temporal mass variations from satellite data, to investigate ice-shelf dynamics and deformations, or to come up with precise station positions and velocities within a terrestrial reference system. However, the ocean tide models show larger uncertainties in the Antarctic seas and (moreover) at areas covered by ice shelves and, therefore, need to be improved. This joint Argentine-German project is a contribution to the International Polar Year 2007/2008 and its project POLENET. After completion of the recordings at Belgrano II by the end of 2007 it is planned to move the equipment to San Martín in order to get a second gravimetric time series during the year 2008.

FLORA AND PALAEOCLIMATE OF THE LA MESETA FORMATION (MIDDLE EOCENE), MARAMBIO (SEY-MOUR) ISLAND, ANTARCTICA. New elements ofthe La Meseta Formation megaflora are described. This unit crops out on the northern third of Marambio (Seymour) Island, Antarctica. Fossilleaves were collected from the middle part of this formation, dated as middle Eocene. Although the fossils are not well preserved, we identified elements assignable to the following families: Nothofagaceae (at least 3 species), Dilleniaceae, Myricaceae, Myrtaceae, and Lauraceae. However, it was impossible to identify some of the fossils, although all could be recognized as dicotyledonous angiosperms. A palaeoclimatic interpretation based on physiognomic analysis (independent of the taxonomy of the elements) indicates ternperate to cool temperate and seasonably moist climate for this forrnation. This interpretation reinforces the existence of a latitudinal gradient between the Antarctic Peninsula and South America and their progressive migration towards the north as consequence of climatic deterioriation during the Eocene-Oligocene.

Extinct Antarctic mammals are exclusively known from several localities at different levels of the La Meseta Formation (Maram-bio/Seymour Island, Antarctic Peninsula; Early to Late Eocene; Reguero et al. 2002). Up to now the recognized taxa are unequi-

Los materiales fósiles consisten en placas aisladas y un pequeño fragmento de la coraza, de naturaleza epitecal, correspondientes a diversos especímenes. Esta armadura epitecal es sólo conocida entre los miembros de la familia Dermochelyidae registrados desde el Eoceno medio hasta la Actualidad. Los especímenes antarticos son tentativamente referidos al género Psephophorus, taxón cuyas especies se registran desde el Eoceno mediosuperior hasta el Plioceno en Europa,

La Meseta Formation is a discontinuity bounded sedimentary unit which crops out on Marambio (Seymour) and Cockburn islands, approximately 100 km SE of the northern tip of the Antarctic Peninsula. The base of this unit is a diachronous surface which intersects all other older units of the island. Along this surface the hiatus increases towards the West. The top is another unconformity below the glacimarine post-Pliocene deposits of the Weddell Formation. The lenticular geometry and the architecture of the internal units was interpreted as filling an incised valley, eroded on an emerging platform after the tilting of the Marambio Group and the Cross Valley Formation beds. The La Meseta Formation has a thickness of 620 m on Marambio island and was divided into three members (1 to III from base to top). Nevertheless, the lithosome architecture, the relationships between facies and the sedimentary palaeoenvironments are better explained using an allostratigraphic scheme. The La Meseta alloformation is 720 m thick and was divided into six allomembers, each representing a sedimentary stage. Due to the regional importance of the unconformities which limit this unit, it is interpreted that it also represents a depositional sequence. The stratigraphy, structural characteristics and facies architecture of the La Meseta Aloformation are better explained considering a tectonic/erosive mixed origin of the unconformities and thus a tectonic control for the history of the valley is proposed. RESUMEN. ESTRATIGRAFÍA DE LA FORMACION LA MESETA, ISLA MARAMBIO (SEYMOUR), ANTÁRTIDA. La Formación La Meseta es una unidad sedimentaría limitada por discordancias que aflora en las islas Mararnbio y Cockburn, ubicadas aproximadamente a 100 km al sudeste del extremo norte de la Península Antártica. La base de esta formación es una superficie diacróniea que intersecta a todas las unidades más antiguas de la isla. A lo largo de esta superficie el hiato se incrementa hacia el oeste. El techo de la unidad es otra discordancia por debajo del depósito glacimarino post-Plioceno de la Formación Weddell. La geometría lenticular y la arquitectura de las unidades internas fueron interpretadas como producto del relleno de un valle incidido, labrado sobre una plataforma emergente con posterioridad al volcamiento de las capas del Grupo Marambio y de la Formación Cross Valley. La Formación La Meseta presenta en la isla Marambio un espesor de 620 m y ha sido subdividida en tres miembros (1 a III de base a techo). Sin embargo, la arquitectura de los litosornas, las relaciones entre facies y los paleoambientes sedimentaríos son mejor interpretados utilizando un esquema de subdivisión aloestratigráfico. La aloformación La Meseta tiene un espesor de 720 m y fue subdividida en seis alomiembros cada uno de los cuales representa una etapa de sedimentación. Dada la importancia regional de las discordancias que limitan esta unidad se interpreta que la misma corresponde también a una secuencia depositacional. La estratigrafía, características estructurales y arquitectura de las facies de la aloformación La Meseta son explicadas de un modo más armónico considerando un origen mixto, tectónico-erosivo, de las discordancias y por lo tanto se propone un control tectónico en la historia del valle.

The biogeographic hypothesis more accepted today is that Antarctica (West Antarctica) and southern South America (Magellan region, Patagonia) were connected by a long and narrow causeway (Weddellian Isthmus) between the Antarctic Peninsula and South America since the Late Cretaceous (Campanian) until the Early Paleogene allowing terrestrial vertebrates to colonize new frontiers using this land bridge. Stratigraphically calibrated phylogenies including large, terrestrial native ungulates Litopterna and Astrapotheria taxa reveal long ghost lineages that extended into the Late Paleocene and provide evidence for the minimum times at which these "native ungulates" were present both on Antarctica and South America. Based on these results we estimate that the Weddellian Isthmus was functional as a land bridge until the Late Paleocene. Our data place the disconnection between Antarctica and South America in the Late Paleocene, indicating that the terrestrial faunistic isolation (Simpson's "splendid isolation") in South America begun at the end of the Paleocene (~56 to 57 m.y.). This faunistic isolation is documented to have occurred at least 25 Ma before the existence of deepwater circulation conditions in Drake Passage (~30 m.y.) based on the onset of seafloor spreading in the west Scotia Sea region. We hypothesize that in the early stages of extension (Late Paleocene, ~55 m.y.) a wide and relatively shallow epicontinental sea developed between the Antarctic Peninsula and South America drowning the Weddellian Isthmus and preventing the faunal interchange for obligate cursorial terrestrial forms.

Palaeostress inferred from brittle mesostructures in Seymour (Marambio) Island indicates a Cenozoic to Recent origin for an extensional stress field, with only local compressional stress states. Minimum horizontal stress (σ3) orientations are scattered about two main NE–SW and NW–SE modes suggesting that two stress sources have been responsible for the dominant minimum horizontal stress directions in the north-western Weddell Sea. Extensional structures within a broad-scale compressional stress field can be linked to both the decrease in relative stress magnitudes from active margins to intraplate regions and the rifting processes that occurred in the northern Weddell Sea. Stress states with NW–SE trending σ3are compatible with back-arc extension along the eastern Antarctic Peninsula. We interpret this as due to the opening of the Larsen Basin during upper Cretaceous to Eocene and to the spreading, from Pliocene to present, of the Bransfield Basin (western Antarctic Peninsula), both...

Middle Eocene land mammals from La Meseta Formation, Seymour (Marambio) Island are reviewed. A taxonomically diverse fossil land-vertebrate assemblage with small and medium-size mammals has been recovered from four localities. The depositional setting is shallow marine and most of the mammal-bearing beds are in reworked, moderate to high energy subtidal facies. The characteristics of these mammals not only confirm but also strengthen the biogeographical relationships between southern South America (Patagonian Province) and the Antarctic Peninsula during the Paleogene and rule out the possibility of a major barrier between these areas. The Antarctic ungulates (Astrapotheria and ?Litopterna) are plesiomorphics in retaining low crowned cheek teeth and are more similar to those from the Pancasamayoran local faunas of southern South America (Patagonia).

y coincide con un horizonte glauconítico. Se analizaron quince muestras las cuales fueron agrupadas en cuatro palinofacies de acuerdo a la composición porcentual de la materia orgánica. La caracterización palinofacial es indicativa de un ambiente de depositación de plataforma marina proximal. La asociación de las palinofacies permitió discriminar la sección estudiada en tres intervalos menores relacionados a tres estadios en el nivel del mar. La integración de estos estadios resulta en una curva de nivel del mar hipotética que refleja un pulso transgresivo-regresivo menor, dentro de una tendencia regresiva general. La máxima profundidad de agua se sugiere cerca de un metro por debajo del límite K-P propuesto. La identificación palinofacial de este pulso es concordante con la idea de un evento transgresivo-regresivo lento y con ciclos internos. La preservación de la materia orgánica a través del límite K-P no sugiere un efecto local del hipotético evento catastrófico global. Considerando la monótona litología de la Formación López de Bertodano que dificulta el reconocimiento de discontinuidades, este trabajo abre la posibilidad de aplicar, en futuras investigaciones, modelos secuenciales basados en el reconocimiento de superficies de máxima inundación.

Formation fills an incised valley and comprises sediments that represent deltaic, estuarine and very shallow marine environments. Forests of both deciduous and evergreen trees were dominated by Nothofagus, podocarps, and araucarian conifers. The La Meseta paleoflora is distinctive in having a predominance of Antarctic taxa; this suggests a seasonal, cold-temperate, rainy c1imate and a latitudinal gradient. Among the terrestrial vertebrates, there are at least nine rnammal taxa, predominantly tiny marsupial s (mostly endemic and new genera). The presence of these marsupials suggests the existence of some form of isolating barrier (c1imatic and/or geographic), which must have allowed development of this endemic fauna. Cornparisons with faunas assigned to the Itaboraian (late Paleocene), Riochican (late Paleocene), Casamayoran (early Eocene), and Mustcrsan (tentatively assigned to the middle Eocene) ages of Patagonia were made. The assemblage of terrestrial vertebrates of the La Meseta Formation is unusual in the dominance of several endemic forms. The occurrence of protodidelphid and derorhynine marsupials, that had become extinct elsewhere in the Eocene of South America, on Seymour Island also indicates that isolation may have allowed extended survival ofthese taxa in theEocene of Antarctica. The nature, distribution, and composition ofthe La Meseta fauna firmly suggest a latitudinal differentiation in the middle Eocene. Paleogeographic evidence suggests that the terrestrial mammals of the La Meseta Formation probably lived under crepuscular and even extended noctumal conditions (assuming that the angle of the earth's spin axis was relatively the same as it is now) during part of the year. VERTEBRADOS EOCENOS TERRESTRES DE ALTAS LATITUDES DE ANTÁRTIDA COMO EVIDENCIA BIO-GEOGRÁFICA. Una biota moderadamente diversa es conocida en la Formación La Meseta (Eoceno-Oligoceno temprano"), isla Seymour, Península Antártica. La Formación La Meseta rellena un valle incidido y comprende sedimentos que representan ambientes estuáricos y marinos muy someros. Bosques con árboles deciduos y perennes estuvieron dominados por Nothofagus, y coníferas podocarpáceas y araucarias. La paleoflora de la Formación La Meseta es distintiva y predominan taxones antártico s que sugieren un clima templado frío, lluvioso, estacional y un gradiente latitudinal. Dentro de los vertebrados terrestres hay 9 taxones de mamíferos, predominantemente pequeños marsupiales, mayormente endémicos y novedosos, que sugieren que alguna forma de barrera de aislamiento, c1imática y/o geográfica, debió haber permitido el desarrollo de esta fauna endémica. Se realizaron comparaciones con las Iaunas asignadas a las edades mamífero Itaboraiense (Paleoceno tardío), Riochiquense (Paleoceno tardío), Casamayorense (Eoceno temprano) y Mustersense (tentativamente asignada al Eoceno medio). La fauna de la Fm. La Meseta es particular por el predominio de varias formas endémicas. La presencia de marsupiales protodidélfidos y derorhinchinos, los cuales ya no se registran en ninguna de las faunas del Eoceno de América del Sur, indica que el aislamiento pudo haber permitido la supervivencia de estos taxones en el Eoceno de Antártida. La naturaleza, distribución y composición de la fauna de la Fm. La Meseta firmemente sugiere una diferenciación latitudinal en el Eoceno medio. Finalmente, las evidencias paleogeográficas sugieren que los mamíferos terrestres de la Formación La Meseta probablemente vi vieron bajo condiciones crepusculares, aún nocturnas (asumiendo que la oblicuidad del eje de la Tierra fue relativamente la misma que la actual), durante parte del año.

Stratigraphy is the science that studies the strata, or beds, of (mainly) sedimentary rocks in order to extract from them the history of the earth’s surface. By grouping the bed successions in stratigraphic units and by studying their geometrical relationships with some simple rules, it creates the fundamental temporal relative framework necessary to understand the origin of the rock units themselves. Several sub-disciplines or methodological approaches (especially biostratigraphy and paleontology) cooperate in the fundamental task of Stratigraphy, which is the correlation, that is, the recognition of the time equivalence of two different sedimentary successions. In this way a standard chronostratigraphic table, or geologic timescale, has been constructed whose divisions are continuously calibrated in terms of absolute age.

The current temporal and spatial context of water-level change, drivers of change, and possible future scenarios of the Laurentian Great Lakes is controversial. Palaeohydrographs are being constructed from measured subsurface elevations of palaeo-swash zones and modelled ages in strandplains of beach ridges that are preserved in embayments along the lakes’ edge. More than 800 elevations and 200 ages have been collected from 15 strandplains to construct site strandplain palaeohydrographs. Palaeo-beach elevations from whole strandplains or sets of correlative palaeo-beaches within strandplains are then used to establish an outlet palaeohydrograph for each lake. Adjusting strandplain palaeohydrograph elevations to account for glacial isostatic adjustment and refining age models help define the outlet palaeohydrograph. Common basin-wide water-level patterns and changes in outlet location or conveyance can then be interpreted. Systematic patterns of elevation and geomorphic/sedimentologi...

Abstract: The composition abundance spatial and temporal distribution of benthic invertebrates on the artificial rocky shore of Tarkwa bay was investigated between May 2003 and April 2004. Samples were collected or counted in-situ in a 1m2 quadrate along a ...

Here we evaluated the response to eutrophication in terms of abundance and diversity of flora and fauna in a semi-desert macrotidal coastal system (San Antonio bay, Patagonia, Argentina, 40 48 0 S) where signs of eutrophication (high nutrient concentration, seaweed blooms, high growth rate of macroalgae) have been reported. We compared abundances and species composition of macroalgae, small infaunal and epifaunal invertebrates, and birds associated with tidal channels of the San Antonio Bay subject to contrasting anthropogenic influence. Macroalgae were more abundant and diverse in the channel closer to human activity where nutrient concentrations were also higher. In contrast to what others have observed in eutrophic sites, small invertebrates and birds were also more abundant and diverse in the channel with macroalgal blooms and high nutrient concentration. The large water flushing during the tidal cycle could prevent anoxic or hypoxic events, making the environment suitable for consumers. Thus, this could be a case in which eutrophication supports high densities of consumers by increasing food availability, rather than negatively affecting the survival of organisms.

Изложена алгоритмическая модель регионального геоэкологического анализа речных бассейнов, предполагающая изучение ландшафтно-гидрологической организация территории, определение уровня антропогенной нагрузки на бассейны рек и оценку качества речных вод. По результатам моделирования осуществлено водоохранное ареалирование Сумской области и водоохранные мероприятия для модельного репрезентативного бассейна. Ключевые слова: геоэкологический анализ, река, бассейн, Сумская область Abstract. The article deals with the algorithmic model of geoecological analysis of the regional river basins. The landscape-hydrological differentiation have been determined, as well as the levels of anthropogenic pressure on river basins has been defined and quality of river water has been estimated. By modeling was carried out the water protection arealing of territory of the Sumy region and the protection measures for the representative model basin.

Bangladesh faces various types of natural hazards from its birth due to geographical location and physiographic sitting. Flood is the most common event among them. North-eastern part of Bangladesh faces flash flood almost every year with large scale of damage. Tanguar Haor, a famous ramsar site of Bangladesh located in Sunamganj district. This wetland adjacent areas are the most vulnerable zone in terms of flash flood hazard. About more than 80% people are the direct victim of this hazard. This study tries to assess the risk and resilience status of flash flood using risk and resilience assessment matrix. To accomplish this research both primary and secondary data have used. Through this work the comparative view between risk and resilience status has tried to represent. That shows the actual penetration of the depth of risk reduction policy making to improve the condition and minimize the losses of flash flood in the study area.

We report on the results of the first measurement of exclusive f 0 ð980Þ meson photoproduction on protons for E ¼ 3:0-3:8 GeV and Àt ¼ 0:4-1:0 GeV 2 . Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the þ À channel by performing a partial wave analysis of the reaction p ! p þ À . Clear evidence of the f 0 ð980Þ meson was found in the interference between P and S waves at M þ À $ 1 GeV. The S-wave differential cross section integrated in the mass range of the f 0 ð980Þ was found to be a factor of about 50 smaller than the cross section for the meson. This is the first time the f 0 ð980Þ meson has been measured in a photoproduction experiment.

AimComprehensive, global information on species&#39; occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species&#39; only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error‐checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org...

Purpose Microplastics have been widely reported to contaminate aquatic environments, particularly impacting marine organisms, but little is known of microplastic contamination of the soil environment. This study compared the distribution of microplastics in forest, urban, and agricultural soils, investigating the reasons for differences in abundance associated with land use. We analyzed distribution and abundance of microplastics in 100 soils, representing different land use types that include forest, urban (traffic and residence), and agriculture the environs of Yeoju City. Sampling plots were located on a systematic grid with 2.5 km × 2.5km spacing. Topsoil (0-5 cm) was collected with a hand auger and samples were pretreated by drying, density separation using ZnCl 2 solution, organic matter digestion, and decompression filtration. Abundance of microplastics was measured by counting using a digital stereo microscope; microplastics were grouped by shapes (fragment, film, fiber, and sphere) and color (black, red, green, blue, yellow, white, and transparent). Fourier-transform infrared spectroscopy (FT-IR) analysis was used to identify polymer type of the microplastics. Results and discussion Soils of Yeoju contained an average 700 pieces•kg -1 of microplastics, but this greatly varied with land use types. Roadside soils had more microplastics (1108 pieces kg -1 ), mostly black styrene-butadiene rubber (SBR) fragments associated with tire dust. Unexpectedly, the largest amount of microplastics was detected not from urban soils but from an upland soil (3440 pieces kg -1 ). The mean abundance of microplastics in agricultural soil was 664 pieces kg -1 , varying with farming types; the highest abundance was at orchard sites, followed by upland, greenhouse, and then paddy field sites. Polyethylene (PE) and polypropylene (PP) were identified from microplastics sampled at upland, greenhouse, and orchard sites, while SBR-derived microplastics were found more widely in all farmland soils, implicating that mulching film usage and farm machinery. Conclusions Soil microplastic contamination is significant and widespread in urban and agricultural soils of Yeoju, but differs in form and distribution, according to the locality of traffic and farming. Atmospheric fallout to forest soils is quantified and found to be significantly impacted by microplastics. The use of mulching film as a source of PE and PP presents particular concern in terms of the effects of microplastic contamination on soil quality, health, and functionality in agroecosystems.

Lead, zinc and cadmium were analysed in a range of subsistence crops cultivated in and around Nairobi city centre. Lead was found to be the only contaminant of concern, being widely dispersed with elevated levels found in crops and soils from both suburban and city centre areas. Extremely high concentrations were recorded in the edible portions of a variety of crops, and high soil Pb leveJs were recorded within 30m of busy roads. Based on these data, it is estimated that subsistence on a diet of crops cultivated in and around Nairobi could increase Pb intake by 10-100 times the FAO/WHO maximum tolerable levels, potentially contributing substantially to existing health problems.

Most available climate/weather stations (e.g., COOP stations) are located in valleys. The few high elevation stations we have (RAWS, SNOTEL) and are relatively sparse, so do not adequately capture temperature variation in steep complex topography. There is growing awareness of just how much information current air temperature models are missing in complex mountainous terrain. For example, cold air drainage and lapse rates vary from night to night. Many terrestrial management decisions (tree planting, growth and yield, species occurrence, etc.) are made at the stand or aspect scale, due to variation in solar insolation, and temperature predictions must match that scale in order to be useful for site-level predictions. For aquatics applications, one of the most important questions is understanding the mechanisms associated with how streams warm up & whether that information can be used to predict which types of streams will be more/less sensitive to future changes. As a result, there is growing interest in using inexpensive sensors to develop massive air temperature monitoring arrays in mountains. We are now beginning to make progress in using sensor networks to empirically downscale temperatures in complex topography (see Holden et al. (2011); Holden et al. (in press); and attachments). However, there are some real challenges to accurately measuring air temperature in forested environments. I'm now in my 3 rd year of deploying air sensor arrays across the northern Rockies, I've learned a lot mainly from mistakes that I've made and will try to share some of that information here (see attachment on tradeoffs). In short, it's a significant challenge to measure air temperature accurately but it's also a very important to try and minimize bias associated with solar radiation. Note that we are inherently dealing with a highly modified radiation environment, because of the presence of trees and vegetation, which all absorb and re-emit radiation. In the end, as a user community, ecologists and climatologists should work toward standardizing our methods for monitoring air temperatures in forested environments. I don't claim to have all the answers, but if interested in discussing further or if you'd like more information on our radiation shield design, you can contact me at:

Abertura: orificio, ranura o hendidura en la pared de la conchilla del foraminífero que comunica el interior o lumen de la cámara con el exterior. Abertura accesoria: abertura que no se comunica directamente con el interior de la cámara, sino que se extiende debajo de estructuras accesorias, como la bulla. Abertura areal: abertura en la cara de la última cámara. Abertura ecuatorial: abertura simétrica en conchillas planoespirales, comúnmente interiomarginal, pero puede ser areal o periférica. Abertura extraumbilical: abertura en las conchillas trocoespirales, en la base de la última cámara, pero sin contacto con el ombligo. Abertura interiomarginal: abertura basal en el margen de la última cámara; en formas enroscadas, puede ser de posición umbilical, extraumbilical o ecuatorial. Abertura primaria: abertura principal de la conchilla. Abertura radiada: abertura asociada a numerosas ranuras divergentes. Abertura umbilical-intraumbilical: abertura ubicada en el ombligo, no extendiéndose fuera de él. Abertura umbilical-extraumbilical: abertura en las conchillas trocoespirales, que se extiende en la base de la última cámara, desde el ombligo hacia la periferia. Acrodonte, Acrodoncia: implantación dentaria en donde los dientes se anclan directamente sobre el margen del hueso, sin presencia de alveolos. Actinotricos: rayos dérmicos formados por elastoidina (colágeno), presente en estadios larvales de algunos dipnoos, celacantos, y actinopterigios, en estadios avanzados son reemplazados por un rayo definitivo menos en algunos teleósteos que permanecen formando la aleta adiposa. Adapical: en dirección o sobre el disco apical (sinónimo de aboral). Adaxial: situado junto al eje o en dirección. Adradial: en dirección o sobre la línea de unión entre una zona ambulacral y una zona interambulacral. Agamonte: espécimen desarrollado a partir de un cigoto, que produce gamontes o esquizontes. Los foraminíferos agamontes, originados por reproducción sexual, son llamados microesféricos o forma B. Ámbar: resina (secreción orgánica) fosilizada de origen vegetal, principalmente de coníferas. Ámbito: punto de mayor circunferencia en la testa de los equinoideos. Ameboide: con la forma de una ameba. Análisis filogenéticos: hipótesis de las relaciones de parentesco entre organismos por medio de la identificación de sinapomorfias, características derivadas en común. Anastomosis: fusión temporal de estipes adyacentes formando una malla ovoide. Anillo perignático: proyecciones internas originadas de placas ambulacrales y/o interambulacrales que rodean el peristoma (apófisis) y a la cual se fija la linterna de Aristóteles mediante músculos protactores y retractores. Anteridio: órgano formador de espermatozoides. En las plantas está protegido por una envoltura estéril. Aparato embrionario: grupo de cámaras en el centro de algunas conchillas de foraminíferos megaloesféricas, más grandes en tamaño y diferentes GLOSARIO en forma y tipo de enroscamiento respecto a las cámaras subsiguientes. Apéndice: estructura anatómica parte de los artrópodos, formada por elementos articulados entre sí, que se insertan en todos o algunos de los segmentos del cuerpo. Apomorfía: estado de carácter evolutivamente novedoso, derivado de otro rasgo perteneciente a un taxón ancestral filogenéticamente próximo. Arquegonio: gametangio pluricelular, rodeado por una cubierta de células estériles. Arqueocito: célula ameboide de las esponjas. Son totipotentes, es decir que tienen la capacidad de transformarse en todos los otros tipos de células. Arquipterigia: aleta que posee un único elemento (homólogo al húmero o fémur) contactando con la cintura correspondiente, y elementos basales que se disponen distalmente y en hilera formando el eje metapterigial. Ascocarpos: un ascocarpo o ascoma, es el nombre dado en micología al esporocarpo característico de los hongos pertenecientes al filum Ascomycota. Ascon: el más simple de los tres grados de organización de las esponjas, en el que el agua entra por los poros y llega a una cavidad central, el atrio, tapizado por coanocitos, y luego es expulsada por una abertura de mayor tamaño llamada ósculo. Astogenia: término biológico que describe el crecimiento combinado de individuos como parte de un organismo colonial. En graptolitos, la astogenia describe la combinación de las ontogenias de los zooides combinadas en una única colonia. Astrorriza: estructura en forma de estrella ubicada en los mamelones de los estromatoporoideos, que forman su sistema exhalante. Atrio: cavidad central de las esponjas. Autapomorfía: apomorfía que ocurre a nivel intraespecífico. Autoteca: Teca de mayor tamaño presente en dendroideos y algunos anisográptidos. Axonóforo: graptoloideos biseriales escandentes y uniseriales en los que el nema está incluido den-tro del tubario (graptolitos biseriales) o embebido en la pared dorsal del tubario (monográptidos). Branquia: órgano respiratorio que presentan muchos animales acuáticos. En el caso de los bivalvos además tienen una función alimentaria. Braquiola: estructura erecta no ramificadas para la captura y transporte de alimento a los ambulacros. Está compuesta por placas biseriales, dos hileras dorsales que incluyen el surco braquial y dos hileras de placas ventrales. Bulla: estructura en forma de ampolla que cubre parcial o totalmente las aberturas primarias o secundarias. Puede tener aberturas accesorias sobre sus márgenes. Solo se da en foraminíferos planctónicos. Cámara suplementaria (camarita, stellar chamberlet): en foraminíferos, extremo umbilical de la cámara, separada de la cavidad de la cámara principal por un séptulo resultante del plegamiento de la lamela interna. Camarilla o camarita: subdivisión de la cámara por un septo. Camptotricos: varillas no osificadas totalmente, ramificadas en su extremo, y similar a los lepidotricos, no son dobles en origen y están cubiertos por escamas; característicos de dipnoos actuales. Canal común: cavidad tabular continua en los estipes formada por las protecas de graptolitos. Canasta faringeal: son órganos de alimentación por filtración con segmentos repetidos ubicados en la faringe. Cancelada: textura de pared en foraminíferos planctónicos con crestas de diseño similar a un panel de abejas. Carcinoecium: estructura de pared quitinosa, calcárea o aglutinante, producida por un hidrozoo simbiótico, que recubre el caparazón de un gastrópodo habitado por un cangrejo ermitaño. Carpelo: estructura que envuelve al o los óvulos de las angiospermas. Puede considerarse un megasporófilo plegado. Carpometacarpo: hueso del miembro anterior conformado por la fusión de los metacarpianos y carpianos. Presente en aves y en los dinosaurios terópodos Alvarezsauridae. Celenterón: cavidad gastrovascular interna del cuerpo de los cnidarios, que comunica con el exterior por una sola abertura, la boca. Cenozoico: división de la escala temporal geológica que se inicia luego del fin del Mesozoico, hace 65 millones de años y que se extiende hasta la actualidad. Ceratotricos: rayos dérmicos en forma de varillas fibrosas no segmentadas ni ramificadas, compuestos por elastoidina (colágeno), son típicos de condrictios permaneciendo en el estadio adulto. Ciclo de vida: la mayoría de las células eucariotas libres se reproducen asexualmente, pero cada tanto cambian a una reproducción sexual, a fin de evitar degeneraciones. En muchos foraminíferos, la alternancia de generaciones producidas sexual y asexualmente, queda documentada en el dimorfismo o trimorfismo de las conchillas. Cigoto: (del griego zygos = yugo, porque une). Óvulo fecundado. Célula diploide (2n) resultante de la fusión de un gameto masculino con uno femenino (ovocélula). Cinetismo craneal: movimiento de los huesos del cráneo entre sí. Cíngulo: extensión anular, más o menos ecuatorial de una espora, en la cual la pared es más gruesa que el cuerpo. Circinadas: hojas se enrollan sobre sí mismas desde el ápice hacia la base. Clado: agrupación que incluye un antepasado común y todos los descendientes (vivos y extintos) de ese antepasado. Clavada: escultura que consiste en clavas (proyecciones con las terminaciones ensanchadas). Cnidocito: células exclusivas de los cnidarios, que segregan una sustancia urticante y contienen un filamento desplegable erizado de espinas. Coanas: aperturas pares a nivel palatal que comunican la cavidad nasal con la cavidad orofaríngea. Coana secundaria: las coanas (o coanas primarias) son abertura que comunican las cápsulas nasales cartilaginosas con la cavidad orofaríngea y que usualmente se encuentran delimitada por los huesos del paladar primario que cubren ventralmente a los sacos nasales. Están presentes en pe-Coanocito: tipo de célula exclusivo de las esponjas, provista de un largo flagelo central rodeado de microvellosidades dispuestas en un círculo, que sirve para atrapar las partículas alimenticias y generar corrientes de agua a través de la esponja. Colpo: modificación de la exina en forma de surco longitudinal. Columella auris: único elemento óseo en el oído medio de tetrápodos no sinápsidos. Contacta medialmente a la ventana oval del oído interno, y lateralmente a la membrana timpánica. Comprimida (vuelta de sección): forma de sección transversal de la vuelta de una conchilla que es más alta que ancha. Conchilla (test): cubierta de la célula del foraminífero, de composición orgánica, aglutinada (compuesta por partículas exógenas al organismo) o mineralizada (calcárea o raramente silícea), compuesta por una o varias cámaras. Constricción: elemento radial y con relieve negativo de la ornamentación de una conchilla. Corresponden a pausas en el crecimiento de la misma. Coralio: esqueleto de un coral colonial. Coralito: estructura esqueletal que forma parte de un coralio, generalmente cónica o en forma de tubo, ocupada por un pólipo. Corriente Circumpolar Antártica: corriente marina de aguas relativamente frías que fluye de Oeste a Este alrededor de la Antártida. Se estableció durante el límite...

Purpose Spatio-temporal variability in soil properties has long been observed on uniformly managed fields. Understanding the spatial characteristics of soil properties would be helpful in recognizing their relationship and the development of site-specific management techniques. The objective of this study was to determine the spatio-temporal variation of P forms and related enzymes and their relationship with some physico-chemical properties in a plot scale. Materials and methods A grid soil sampling (10×10 m) was used to measure the spatial variation of soil properties across a 0.4-ha field. Soil samples were collected at 50 points from the upper 20 cm of luvisols in April and August 2007. The total (P T ), available (P A ), inorganic (P I ), organic (P O ) phosphorus concentration, and acid (P AC ) and alkaline (P AL ) phosphatase activity were analyzed. Additionally, total organic carbon (TOC), soil pH KCl , and clay content were determined. Data were evaluated using classical statistical and geostatistical methods. Results and discussion Both enzyme activities were significantly higher in April than in August, while the P T and P I concentration were significantly lower. The concentrations of P O and P A did not significantly differ between sampling dates. The spherical or mixed (spherical/linear) models with the nugget effect were fitted to the calculated semivariograms. The P A and TOC concentrations on both sampling dates as well as P AC activity in April were situated in the strong variability class, the P I concentration in April revealed a weak spatial variability and the other properties were in the moderate variability class. The clay content revealed a pure nugget effect. The range of the influence that was calculated for the properties ranged from 16.5 to 50.0 m. Kriged maps showed that temporal variability was observed in the spatial patterns of the P I and TOC concentrations and P AC activity. Conclusions Results from this study can help us to understand and predict the contribution of internal factors (i.e., soil type) in the total variability of soil properties that can interfere with the influence of soil management practices. The spatiotemporal variability showed that the studied area was temporally unstable and the implication of these findings is that more frequent sampling, at least several times throughout the growing season, must be included in the sampling strategy in order to better understand whether P forms and related enzymes show any permanent spatial patterns in soil all of the time or whether they are more randomized.

Purpose Knowledge about the spatio-temporal variability of soil microbial properties is crucial in evaluating their structurefunction relationship and their impact on ecosystem functions. The aim of the study was to determine the spatio-temporal variation of the selected microbial properties at the surface horizon in a conventionally managed arable field. Materials and methods The area selected for the research, which was mainly covered with typical Luvisols, was a uniformly managed system that was considered to be homogenous in respect to texture (mostly loamy fine sand). Winter wheat was cultivated after winter rape as the forecrop. A grid soil sampling (10 m × 10 m) was used to assess the spatial heterogeneity of soil properties across a 0.5-ha field. Soil samples were collected at 50 points from the upper 20 cm of soil in April and August 2007. Colony-forming units (CFUs) of bacteria, fungi and actinomycetes, and basal respiration (BR) were analyzed. Data were evaluated using classical statistical and geostatistical methods. Results and discussion Fungal CFUs were significantly lower than the bacterial ones with a B/F (bacteria/fungi) ratio of 80.0 in April and 45.1 in August. Bacterial CFUs, B/F ratio, and BR level revealed significantly higher values in April than in August, while fungi showed the opposite trend. Other studied properties did not show significant differences between sampling months. Only some of the properties, such as the bacterial community in August, the number of actinomycetes in April, and qCO 2 on both sampling dates, revealed significant spatial autocorrelation (Moran's I) and were spatially dependent at the scale of sampling grid, whereas the qCO 2 revealed a higher differentiation in the spatial pattern between April and August than the other studied properties. Most of the spatially correlated properties were in the weak variability class (a nugget effect > 75%), while only the qCO 2 (August) ratio was in the moderate variability class (a nugget effect between 25 and 75%). Conclusions Most of the microbial-related properties did not exhibit a spatial structure at the examined scale, thus suggesting that changes in these properties would be detectable at a distance shorter than 10 m. More frequent seasonal sampling must be included in the sampling strategy in order to better understand whether studied properties show any permanent spatial patterns in soil over time or whether they are more randomized.

Purpose The application of bio-fertilizers is one of the management practices that can help to maintain or increase the content of organic matter (OM) and improve soil fertility in arable soils. While some results have been obtained in relation to the influence of bio-fertilizers on organic matter content, less in known about the fractional composition of humus. The aim of this study was to determine the effects of the bio-fertilizer UGmax on soil total organic carbon (TOC), dissolved organic carbon (DOC), and the fractional composition of organic matter (C of humic acids (CHAs), C of fulvic acids (CFAs), and C in humins) in the humus horizon of an arable field. Measurements were taken in 2005 before the application of UGmax and in 2008, 3 years after its application, which was done in 2005, 2006, and 2007. Forty soil samples were taken in 2005 (the control year without UGmax), while 20 samples were taken after UGmax treatment and 20 from the control in 2008. Samples were always collected after the plants were harvested. Results and discussion After the 3-year period of the experiment, the TOC content was 6.3 % higher in plots on which UGmax was applied in comparison to the control, while the DOC content was 0.19 percentage points lower after 3 years of bio-fertilizer use as compared to the initial year of the experiment. The contribution of DOC to TOC decreased significantly after the application of UGmax in comparison with the control. The content of CFAs and its contribution in the TOC pools in soil without UGmax was higher at the end of the experiment compared to the beginning, while there was an inverse relationship in the soil with the bio-fertilizer. In comparison with the control, organic matter in the soil treated with UGmax had a higher content of C of humic acids, C in humins, and higher CHAs/CFAs ratio. Conclusions We conclude that the use of a bio-fertilizer that increases the stable fractions of organic matter provides evidence of an increase in the soil OM stability. In turn, the contribution of the organic matter fractions that are more resistant to decomposition is crucial for increasing soil carbon sequestration.

Purpose Artificial soil sealing in urban areas has attracted increasing attention because of its potential hazard to urban ecosystem. Covering soils with impervious materials has a significant impact on their properties and is essentially an irreversible process. In contrast to natural, open soils, sealed soils undergo a significant alteration of their physicochemical properties, and in turn, negatively influence microbial biomass and enzymatic activity. Materials and methods In general, 33 soils from different parts of the city of Toruń (NW Poland) were sampled and divided into 3 groups according to the degree of soil sealing: (1) soils sealed with semi-pervious concrete paving slabs (A), (2) soils sealed with impervious surfaces, such as asphalt and concrete (B), and (3) non-sealed soils (the reference group-C). Soil samples were assayed for (1) microbial biomass carbon (MBC), and nitrogen (MBN) and soil respiration activity (RESP), (2) the activity of soil enzymes, and (3) physicochemical properties. Results and discussion Soil sealing significantly reduced the content of carbon and nitrogen (both total and microbial), soil respiration, the activity of urease, and fluorescein diacetate hydrolysis compared to non-sealed soils (C), while the degree of soil sealing did not significantly affect these properties. Soil moisture and nitrate reductase activity were the only properties significantly differentiated by the degree of soil sealing. Canonical correlation analysis indicated that soil biological activity was caused mainly by the variation in MBC and MBN content, as well as dehydrogenase, catalase, and cellulase activities. The highest correlation was obtained between the soil moisture and the first canonical variable for microbial biomass and enzymatic activity. Conclusions The results showed that the artificial sealing in urban areas can significantly alter the soils by reducing their carbon and nitrogen content as well as microbial biomass and its activity compared with open soils. The analysis of variance showed that the degree of soil sealing did not affect most of the studied soil properties, although the differences in raw data between impervious and semi-pervious sites were remarkable.

The Tagus Estuary is one of the largest in Europe with 320 km2, and it has been, for centuries, a gateway to Lisbon. This study focuses on the Moita-Montijo Bay and on the recent dynamics of its tidal flats and saltmarshes. Aerial photographs, orthomosaics, and very high-resolution satellite imagery were used to analyze landcover and shoreline changes. Tidal flats have shown expansion from 1977 to 1995, but since then, contraction dominated, with a change of position of the tidal flat edge of −2.8 m/year in the north bank and −4.2 m/year in the south bank of the Montijo channel. Most contraction occurred along the route of the fast transport catamarans that started operating in 1995, while in the sector without catamaran navigation, expansion was observed. Saltmarshes have been suffering contraction since 1958, with increased rates after 1995 (−0.38 to −0.44 m/year), especially along the catamaran route (−0.57 to −1.27 m/year). The analysis of the wake generated by different vessel ...

The Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia has undertaken a systematic analysis of the isotopic (Sr, Nd, and Pb) compositions and concentrations of a broad compositional range of U.S. Geological Survey (USGS) reference materials, including basalt (BCR‐1, 2; BHVO‐1, 2), andesite (AGV‐1, 2), rhyolite (RGM‐1, 2), syenite (STM‐1, 2), granodiorite (GSP‐2), and granite (G‐2, 3). USGS rock reference materials are geochemically well characterized, but there is neither a systematic methodology nor a database for radiogenic isotopic compositions, even for the widely used BCR‐1. This investigation represents the first comprehensive, systematic analysis of the isotopic composition and concentration of USGS reference materials and provides an important database for the isotopic community. In addition, the range of equipment at the PCIGR, including a Nu Instruments Plasma MC‐ICP‐MS, a Thermo Finnigan Triton TIMS, and a Thermo Finnigan El...

The purpose of this article is to present the methodology for assessing seismic risk at the local level, using the Ungheni district of the Republic of Moldova as a case study. The Vrancea earthquake, with a magnitude of Mw=7.9 and a return period of 475 years, was chosen as the design eismic action. First, a specified earthquake scenario was analyzed using a special macroseismic attenuation equation, which allowed estimating the likely tensity distribution in the study area. Then, based on statistical data and field assessments, the vulnerability of buildings and the seismic risk for the Ungheni city and the neighboring villages were estimated.

A palaeomagnetic research was carried out in the Arroyo Loncoche area (provincia de Mendoza), where a 300 m thick succession of sedimentary rocks bearing ammonites: Vaca Muerta Formation (TithonianBerriasian) is outcropping. Levels of paleomagnetic sampling were located according to the ammonite zoning in the Andean region, which comprises from Virgatosphinctes mendozanus Zone to Spiticeras damesi Zone. Afterwards imparting alternating field and thermal demagnetizations, reliable magnetic behaviors were observed. Then, it was possible isolate a reverse polarity zone toward the base of Vaca Muerta Formation and another normal polarity zone toward the upper part. These preliminary results are consistent with the international geomagnetic polarity scale.