Continental Plains Research Articles

Floodplain carbon dioxide emissions strongly exceed those of the main river stem: A case study of the Ob River, western Siberia

The importance of floodplains in carbon (C) evasion from the lotic systems is especially important in continental plains of low runoff such as the organic-rich Western Siberian Lowland (WSL). To quantify the relative importance of the floodplain compared to main stem CO2 emissions, we monitored a large region of the Ob River’s middle course (permafrost-free zone) over 3 months from spring to summer. We calculated seasonal water coverage using remote sensing, GIS and hydrologically-based approaches and measured CO2 emissions using floating chambers. There was a strongly pronounced seasonality in the water area’s extent of the floodplain with water covering > 40 % of land during the ∼ 30 days of the most intensive spring flood (May – June) and subsequently declining to ≤ 10 % during summer (July-August). Maximal CO2 emissions were recorded in most shallow water bodies of the floodplain, notably in temporary flooded fens and birch forests. The CO2 emissions during the study period ranged from 0.2 ± 0.2 to 0.9 ± 0.2 g Cm−2 d-1 for the floodplain and 0.03 ± 0.34 g C m−2 d-1 for the Ob’s main channel.CO2 emissions from the floodplain were ∼ 163 ± 20 t C per km for the river’s main stem during the 95 day study period. The partial contributions of temporary flooded zones, main stem, and permanent lakes / secondary channels to total emissions (1820 km² area) were 70, 16, and 14 %, respectively. Over spring and summer seasons, contributions from flooded zones ranged from 43 to 99 % of total CO2 emissions from water surfaces of the Ob River’s middle course. Extrapolation of obtained results to the entire territory of the Ob River floodplain indicates that not accounting for the floodplain emissions may sizably—up to an order of magnitude—underestimate the CO2 emissions from riverine systems in Western Siberia during open water period. Future work on the Ob River floodplain in the permafrost-bearing zone should be prioritized and would allow adequate upscaling of C emission from this environmentally important territory.

Climate and Weather Condition of Balochistan Province, Pakistan

The study discusses the climate of Balochistan with a special focus on the variation of weather condition taking into account the mean monthly precipitation, temperature, humidity, atmospheric circulation, air pressure, evapotranspiration and solar energy covering the time duration of 1931-2020 (normal data). The physical barriers that bring variations in the climate of Balochistan contain geographical location, ocean, geomorphology, land use, natural vegetation, and continental extent. Based on precipitation, the province has been divided into two main regions that are arid and semi-arid, while the temperature zones are hot, warm, mild and cool. The southern and eastern part of the province receives heavy rain in the summers (monsoon), whereas it is from the western depressions during the winter season. Balochistan experiences four rainy seasons in winter (cold), pre-monsoon season (warm), monsoon season (hot), and post-monsoon season (mild). Owing to tropical (coastal) and sub-tropical continental characteristics, the area familiarizes two foremost seasons namely winter and summer. The summers of the area long for 5 months in hilly areas while 7 months in continental plains and coastal regions; whereas, winters cover five months in the plains and seven months in the mountains. Based on the appropriation and fluctuation in climate constituents, Balochistan has been classified into two main, 6 meso, and 9 microclimate and weather zones. According to Global Climate Risk Index, 2021, Pakistan has been ranked at 8th in the list of top ten global climate high-risk countries, which are exposed to the ongoing climate change and requires attention to resolve the issue.

Geoelectrical Characterization of Coastal Aquifers in Agbado-Ijaye, Lagos, Southwestern Nigeria; Implications for Groundwater Resources Sustainability

Water is a natural resource; its availability depends on climatic and geological conditions, and it is invariably controlled by human activities. Agbado-Ijaye lies within a coastal area, where local communities have been facing incessant water shortages, especially during the dry season. This study investigated the groundwater-bearing geological unit(s) using hydrogeophysical techniques in the coastal environment. The electrical resistivity technique, involving vertical electrical sounding (VES) and two-dimensional (2D) electrical resistivity imaging via Wenner array electrode configuration, was used to characterize the geoelectric distribution. Twenty VES stations were investigated and current electrodes (AB/2 m) spacing expanded from 1–200 m; four 2D electrical resistivity imaging traverses having a length of 200 m each and interelectrode spacing of 10 m (level 1) to 60 m (level 6) was adopted. Four geoelectric units were delineated, namely: topsoil (15–251 Ωm), clayey (28–100 Ωm), clayey sand (125–190 Ωm) and sandy (205–876 Ωm) with thicknesses ranging from 0.7–1.3 m, 4.1–19.0 m, 2.6–15.6 m and undefined depth, respectively. The 2D imaging sections also detected similar geoelectric layers, corroborating the VES-derived sections. The inverted sections delineated two different aquifers: the shallower low-yield aquifer comprising sandy clay/clayey sand units with a maximum depth of about 5.5 m. This layer is adjudged to be the continental plain sand of the Benin Formation. The deeper high-yield aquifer with a maximum depth of 30.4 m is a beach sand unit that belongs to the Tertiary Alluvium of the Dahomey Basin. The study showed that hydrogeophysical investigation is vital in exploring, developing, and managing coastal groundwater resources.

Constraining depositional evolution and reservoir compartmentalization in a mixed carbonate-siliciclastic lacustrine system: The Yacoraite formation, Salta Group, NW Argentina

The mixed carbonate-siliciclastic Yacoraite Formation, Salta Group in northern Argentina has been interest of recent studies searching for potential analogues for the South Atlantic pre-sal carbonates. Microbial lacustrine carbonates are important reservoir systems and their characteristics and stratigraphic packaging are a major factor impacting compartmentalization. This study provides sedimentological and facies analyses combined with petrographical, isotope geochemical and petrophysical analyses of lacustrine clastics and carbonates using an example from the Yacoraite Formation (Salta Group) in northern Argentina (Tres Cruces sub-basin).The Yacoraite Formation records the evolution of a lacustrine system responding to basin scale tectonic processes and climatic conditions and is interpreted as a microbially-related mixed carbonate clastic lacustrine system comprising 8 main Facies types, deposited in either a perennial or an ephemeral system. The most dominant architectural elements are: Sandstones with interbedded shales (F1), Shales with interbedded sandstones and siltstones (F2), Thick-bedded oolitic grainstone (F5), Thin-bedded oolitic grainstone-packstone (F6) and Stromatolite boundstone (F8). These facies types allow to differentiate two types of lacustrine environments: Perennial (Stage I) vs Ephemeral (Stage II) intercalated with episodes of continental plains deposition, arranged in three depositional sequences (Yacoraite I, II and III), each recording either transgressive or a regressive-transgressive trend.Carbonate and clastics are arranged in cycles during the Perennial l Stage suggesting that the depositional system responded in patterns attributable to reciprocal sedimentation, whereas, during the Ephemeral Stage 2, spatial coexistence of clastic and carbonate seem to be the case rather that cyclic vertical superposition.Thick-bedded oolitic grainstone and Stromatolites (F5 and F8 respectively) of the perennial lacustrine system show laterally continuous and thick beds with the best reservoir properties. Furthermore, the Sandstones with interbedded shales (F1) are characterized by intermediate values of porosity and permeability, which would not result in permeability barriers. On the other hand, Thin-bedded oolitic grainstone-packstone (F6) of the ephemeral lacustrine system are characterized by a high degree of heterogeneity due to their limited areal distribution and their complex spatial variability with Shales with interbedded sandstones and siltstones (F2).

Railway Heritage of the Samaritá station in São Vicente - SP

During the economic cycle of coffee and technological development attributed to the arrival of railways on the coast of São Paulo, São Vicente – SP as well as the cities of the interior of the state of São Paulo, witnessed potential economic and urban advances generated by industrial activities throughout the first half of the twentieth century. From the implementation of the railway, eight railway stations were built in the mountains and on the continental plain of the city being, the first, Samaritá. Given this importance, we justify this research in order to build an understanding about the apogee and decay of railway and industrial heritage in the city, under the section of this station. Based on historiographical research through maps, photographs and documents it was possible to clearly understand the implementation of the railway bed in the continental region of the city, where new urban groupings derived from the railway tracks had emerged. The vast majority of São Vicente's railway stations have been abandoned or demolished, and the last exemplary on the Vicentine plain that remains is samaritá station. Thus, the work analyzes either the emergence of the railroad, from the perspective of the building that generates the first occupation in the continental plain of the city and its process of deterioration, when presenting the current situation of the railway complex.

A Dirichlet process model for change‐point detection with multivariate bioclimatic data

AbstractMotivated by real‐world data of monthly values of precipitation, minimum, and maximum temperature recorded at 360 monitoring stations covering the Italian territory for 60 years ( months), in this work we propose a change‐point model for multiple multivariate time series, inspired by the hierarchical Dirichlet process. We assume that each station has its change‐point structure and, as main novelties, we allow unknown subsets of the parameters in the data likelihood to stay unchanged before and after a change‐point, that stations possibly share values of the same parameters and that the unknown number of weather regimes is estimated as a random quantity. Owing to the richness of the formalization, our proposal enables us to identify clusters of spatial units for each parameter, evaluate which parameters are more likely to change simultaneously, and distinguish between abrupt changes and smooth ones. The proposed model provides useful benchmarks to focus monitoring programs regarding ecosystem responses. Results are shown for the whole data, and a detailed description is given for three monitoring stations. Evidence of local behaviors includes highlighting differences in the potential vulnerability to climate change of the Mediterranean ecosystems from the Temperate ones and locating change trends distinguishing between continental plains and mountain ranges.

Climate and Weather Condition of Balochistan Province, Pakistan

The study discusses the climate of Balochistan with a special focus on the variation of weather conditiontaking into account the mean monthly precipitation, temperature, humidity, atmospheric circulation, air pressure,evapotranspiration and solar energy covering the time duration of 1931-2020 (normal data). The physical barriers thatbring variations in the climate of Balochistan contain geographical location, ocean, geomorphology, land use, naturalvegetation, and continental extent. Based on precipitation, the province has been divided into two main regions that arearid and semi-arid, while the temperature zones are hot, warm, mild and cool. The southern and eastern part of theprovince receives heavy rain in the summers (monsoon), whereas it is from the western depressions during the winterseason. Balochistan experiences four rainy seasons in winter (cold), pre-monsoon season (warm), monsoon season(hot), and post-monsoon season (mild). Owing to tropical (coastal) and sub-tropical continental characteristics, the areafamiliarizes two foremost seasons namely winter and summer. The summers of the area long for 5 months in hilly areaswhile 7 months in continental plains and coastal regions; whereas, winters cover five months in the plains and sevenmonths in the mountains. Based on the appropriation and fluctuation in climate constituents, Balochistan has beenclassified into two main, 6 meso, and 9 microclimate and weather zones. According to Global Climate Risk Index,2021, Pakistan has been ranked at 8th in the list of top ten global climate high-risk countries, which are exposed to theongoing climate change and requires attention to resolve the issue.

Distribution Pattern of the Benthic Meiofaunal Community Along the Depth Gradient of the Western Indian Continental Margin, Including the OMZ and Abyssal Plain

The continental margin harbors a variety of habitats that support incredible biodiversity and the function of their oceans' ecosystems. The meiofauna is considered a significant component of the benthic faunal community from the polar to the tropical regions. The meiofaunal community in the deep Indian Ocean, especially along the depth gradient, is poorly investigated. The present study aims to explore the benthic meiofaunal community structure along the depth gradients and its associated environment in the western Indian continental margin (WICM) and abyssal plain in the eastern Arabian Sea. Sediment samples were collected from seven different depths (111–3,918 m) along the WICM including the oxygen minimum zone (OMZ) and abyssal plain. A total of 22 taxa (groups) were encountered along the WICM. The nematodes (85%) were the most dominant taxa in all the depths, followed by copepods (11%), nauplii (5%), and polychaetes (1.36%). Our results suggest that (a) the organic matter has accumulated in OMZ sites; (b) a high amount of total organic carbon did not influence the meiofaunal density or biomass; (c) oxygen and depth gradients were significant drivers of the meiofaunal community, low levels of oxygen contributed to lower taxa diversity and density at 485 and 724 m depths; (d) a significant relationship of meiofaunal density and biomass with chloroplastic pigment equivalent (CPE) values indicates pelagic-benthic coupling. Copepods, nauplii, tanaidaceans, isopods, kinorhynchs, and cumaceans were affected by the low-oxygen conditions at the OMZ sites. Enhanced meiofaunal diversity, density, and biomass at deeper sites (non-OMZ-D) was attributed to increased abundance of copepods, nauplii, tanaidaceans, isopods, kinorhynchs, and cumaceans and were mostly concentrated on the surface sediment (0–4 cm) triggered by enhanced bottom-water oxygen and freshness of available food outside the OMZ except 3,918 m. Therefore, the present study showed the meiofaunal community pattern with respect to depth gradients and their related environmental changes, including the OMZ along the WICM and abyssal plain in the Arabian Sea. Based on this study, the future extent of these underestimated marine ecosystems must be considered a priority to understand its functional consequences.

Submarine groundwater discharge detection on the coast of Buenos Aires using 222Rn and geoelectrical methods

Submarine groundwater discharge (SGD) is a complex hydrological process which occurs in the continent–ocean interface and plays an important role in coastal dynamics. The detection of groundwater discharge from the sandy freshwater aquifer towards the Atlantic Ocean was proposed on the western coast of Buenos Aires Province (Argentina). There are different methods used to detect SGD. In this study, 222Rn as a tracer, electrical resistivity tomography (ERT) and flow maps were used as the methodology. 222Rn activity was measured in the wells, at the beach (tidal pools and surf zone) and along a transect 200 m from the coastline where geo-electrical method was also used. Groundwater depth was measured in the wells and groundwater contour maps were made .222Rn activity in the wells varies from 16 and 173 dpm/L, at the beach the values are between 28 and 48 dpm/L and along the coastline they oscillate between 1.3 and 20.5 dpm/L. The ERT shows a high resistivity layer close to a depth of 3-4 m from the sea floor, which would indicate the presence of freshwater. Groundwater contour maps show discharge toward the continental plain to the west and toward the sea to the east. There is no precedent related to the application of these methodologies in the study area, therefore this study is of interest to increase our knowledge of the coastal hydrodynamics.

Quinoa Productivity and Stability Evaluation through Varietal and Environmental Interaction.

Chenopodium quinoa is a pseudocereal species identified as a potential crop to mitigate world food security. It has the ability to adapt to diverse agro-ecosystems ranging from sea level to over 4000 masl. Its cultivation in Morocco began in 1999, as it is tolerance to drought, salinity, and frost, and it can grow on marginal soils. It has exceptional nutritional value, as it is rich in proteins, essential amino acids, mineral nutrients, trace elements, vitamins, and unsaturated fatty acids. The present study aims to evaluate the adaptation of 14 quinoa varieties and lines from four different origins through fourteen agro-morphological characters. The experimental trials were conducted at five contrasted agro-climatic sites across the central part of Morocco. The data analysis showed high variability among the tested varieties and between sites for all assessed traits. The Meknes (foot-hill plain) site was the most productive; its grain yield reached 78.6 qx/ha. At the Rabat (coastal land) and Berrechid (continental plain) sites, grain production was respectively 56.4 and 45.9 qx/ha. The SW2 Moroccan line produced the highest grain yield that reached 78.3 qx/ha across sites. The Danish variety Titicaca presented the best harvest index (HI = 0.69) as well as the best “thousand kernel weight” (TGW = 3.4 g). As the mildew infection evaluation, the Vikinga and Titicaca varieties ranked the most sensitive to Peronospora farinosa. The germination rates of the harvested seeds were prejudiced by the sites’ high temperatures and were low in Tinejdad (oases site) and El Kbab (mountain plateau). The best average germination rate across sites was that of the Puno variety (84.5%). According to the Additive Main effects and Multiplicative Interaction analysis (AMMI), 23% of the grain yield variability is due to the genotype, while 32% is due to the site by the variety interaction contribution to the production variability. AMMI analysis also ranked the varieties according to their productivity and stability value. Accordingly, two varieties that have yielded above the overall average (42.7 qx/ha) are considered stable; those are Riobamba and W11, which is a local selected line. Titicaca, ILLPA, Atlas cultivars and the SW2 local line presented the best grain yield in one of the experimental sites but performed not as well on the others.

Key hydrological processes in the Del Azul Creek basin, sub-humid Pampean Plain

Groundwater plays an important role in the economic development of the Chaco-Pampean Plain (Argentina), where industry, agriculture and cattle farming are the main economic activities. The 66% of the country's population lives in this area. The low slopes of this region condition the water movement and the occurrence of physical and chemical processes. The aim of this work is to update the hydrological conceptual model of the Del Azul Creek basin (Buenos Aires Province), a sub-humid and continental plain, using environmental tracers. In total, the study was based on the analysis of 201 samples (stable isotopes) and 184 samples (chemical data) including rainwater, surface water and groundwater. The temporal and spatial variation in the isotopic composition of rainfall and the hydrological physical-processes, evaporation, surface water-groundwater interaction and recharge were studied. Isotopic compositions of rainfall revealed a seasonal variation across the basin. Low δ18O rainfalls occur during the coldest seasons, while high δ18O rainfalls occur during the warmest seasons. The isotopic compositions of rainfall varied only during the cold period in the upper basin. At this time, the lowest δ18O rainfall fell in the upper basin, while in the other areas and during the warmer seasons, no differences were observed. Evaporation was a relevant process in the flatter area of the basin, mainly during the warmest seasons. Samples taken from the wetlands and from the lower section of the Del Azul Creek were strongly evaporated. In the first 30 m depth of the aquifer, groundwater reflected the isotopic composition of rainfall from the warmest seasons, thus revealing seasonal preferential recharge and a good hydraulic connection. This study provides direct evidence showing that both evaporation and the surface water-groundwater interaction are processes that play a key role in the control of the isotopic and chemical composition of water.

A multi-parameter study of groundwater–seawater interactions along Partido de La Costa, Buenos Aires Province, Argentina

Submarine groundwater discharge (SGD) is a complex hydrological process which occurs at the continent–ocean interface and plays an important role in coastal dynamics. The main objective of this study was to detect groundwater discharge from the sandy freshwater aquifer towards the Atlantic Ocean along the western coast of Buenos Aires Province (Argentina) using multiple methods. 222Rn as a tracer, electrical resistivity tomography (ERT), and hydrogeological information were applied to detect and quantify SGD. 222Rn activity was measured in wells, at the beach (tidal pools and surf zone) and along a transect ~ 200 m from the coastline coincident with geoelectrical measurements. Groundwater depth was measured in wells, and from these data, groundwater contour maps were made. 222Rn activity in wells varies from 16 and 173 dpm/L; at the beach, the values are between 28 and 48 dpm/L; and along the coastline, they oscillate between 1.3 and 20.5 dpm/L. The ERT shows a high resistivity layer close to 3–4 m depth from the sea floor indicating the presence of freshwater. Groundwater contour maps show discharge toward the continental plain to the west and toward the sea to the east. There is no precedent related to the application of these methodologies in the study area which results of interest for the knowledge of the coastal hydrodynamics.

What Could the ‘Sea Ice Machine’ do to its People? On Lateglacial Doggerland, Marine Foraging, and the Colonisation of Scandinavian Seascapes

ABSTRACT ‘Climate’ is rarely experienced directly – contrary to day-to-day ‘weather’ and ‘seasons’ that manifest in landscapes (‘weather-worlds’). This paper elaborates the role of sea ice and sea ice hunting outside the lateglacial Doggerland beaches. The winter–spring sea ice was a seasonal extension of the continental plains, and a potential meeting ground for the human hunters of the plains and the mammals of the sea. Here, the hunters could observe and experience that seals were easy prey and that seals were similar to the familiar terrestrial megafauna; providing meat and blood, bone, skin, bladders and sinews, and ample supplies of fat (blubber) that also could heat dwellings. Seals on the ice could be hunted with similar methods and equipment as terrestrial animals – without the need of boats and the risks of cold, open sea. The Doggerland sea ice was a meeting ground of land and sea that could have been imperative in the development of marine foraging and the subsequent colonisation of Scandinavian seascapes. Levy Bryant’s ‘Machine Oriented Ontology’ may be instrumental to envision the sea ice and its potential for the lateglacial hunters in Northwest Europe.

The Mad Monk Manifesto: A Daoist Cry for a Paradigm Shift Now

The Mad Monk ManifestoA Daoist Cry for a Paradigm Shift Now1 Monk Yun Rou You hold in your hands a manifesto for change, an 11th-hour emergency survival manual utterly devoid of bright-future reassurances and New Age pabulum. You will find nothing here about how thinking positive-thoughts will help you look great in tight jeans, how brilliant your children are, how the whales really love us for killing them, or how the work you do in your high-salaried corporate position is critical to the survival of the universe. Although I hope you will find my words as spiritual as they are political, I am no Pollyanna. I don't believe that all will soon be right with the world or that we are almost through the tough times. I don't accept social media as a substitute for reality, or that our evolving into half-digital cyborgs will take away all our pain. I believe in the transformative power of both meditation and love, but don't believe either or both will solve all our problems. I am a monk, not a carnival barker, and thus skeptical of quick and easy fixes; thus, I hope you will find the ones I offer in the chapters that follow to be substantial, meaningful, and worthwhile even though they may require effort. When contemplating these changes, please remember that change is the only constant our world offers. [End Page 229] I begin with such straightforward urgency because our floating home, zooming through the galaxy at high velocity inside the wildly spiraling solar system that contains it, has become a watery blue purgatory.More slaughterhouse than paradise, more frenzied, violent battlefield than garden of enlightenment, more cesspool of fractiousness than temple to unity, our beautiful planet is dying and we are its murderers. Wonders remain, but the effects of global industrialization executed upon a foundation of Western values, guarantee such wonders won't last long. The values I refer to are mostly about what it means to be human, but also our greed, material excesses, species-centrism, the religiously-based notion of human hegemony over the natural world, and, of course, overpopulation. The last item on that list may be obvious to those suffering traffic jams, polluted parks, and the disappearance of peace and quiet, but its global consequences are actually complex, underestimated, and inaccurately predicted. Wars over land, air, and water have already begun. The macro-organism we call Planet Earth, desperate to survive in its current, diverse glory, uses various methods to fight its way out from beneath the meaty weight of the human herd. These weapons include diseases, wars, automobile accidents, gender variances, and religious fundamentalism—anything and everything that pares our numbers. Even so, there are still those who believe that their god encourages them to have ten children or more. And then there is climate change, another feature of our greed, lack of sensitivity, and the religiously fundamentalist notion that the planet is our playground. Regardless of how many political leaders label it a hoax, weather patterns are changing at human, not geological, speed. It's tough to wrap our minds around the size of the changes and how soon they will be here. I write this as a displaced victim of one of the largest Atlantic hurricanes on record, having just watched the state of Texas suffer a thousand-year flood, and now seeing the state of California battling the largest and most deadly wildfire outbreak in recorded history. Tropical cyclones are growing more violent and frequent, ice caps are melting, glaciers and permafrost are disappearing, island nations are in existential peril. Tens of thousands of miles of coastline will soon be lost to oceans, which are acidifying so rapidly, jellyfish will be the only "seafood" they can soon support. Vast continental plains are becoming deserts while [End Page 230] deserts are becoming dustbowls, putting our food supply in jeopardy.Deforestation and marine algae die-offs suggest that the oxygen we breathe will eventually vanish. If all these challenges appeared in an apocalyptic Hollywood thriller, the screenwriter would be told to tone things down so as to make them believable. Consider, too...

Urban Flood Simulation Using MODCEL—An Alternative Quasi-2D Conceptual Model

Urban flood modelling has been evolving in recent years, due to computational facilities as well as to the possibility of obtaining detailed terrain data. Flood control techniques have also been evolving to integrate both urban flood and urban planning issues. Land use control and flow generation concerns, as well as a set of possible distributed measures favouring storage and infiltration over the watershed, also gained importance in flood control projects, reinforcing the need to model the entire basin space. However, the use of 2D equations with highly detailed digital elevation models do not guarantee good results by their own. Urban geometry, including buildings shapes, walls, earth fills, and other structures may cause significant interference on flood paths. In this context, this paper presents an alternative urban flood model, focusing on the system behaviour and its conceptual interpretation. Urban Flood Cell Model-MODCEL is a hydrological-hydrodynamic model proposed to represent a complex flow network, with a set of relatively simple information, using average values to represent urban landscape through the flow-cell concept. In this work, to illustrate model capabilities, MODCEL is benchmarked in a test proposed by the British Environmental Agency. Then, its capability to represent storm drains is verified using measured data and a comparison with Storm Water Management Model (SWMM). Finally, it is applied in a lowland area of the Venetian continental plains, representing floods in a complex setup at the city of Noale and in its surroundings.

Exploring human responses to climatic fluctuations and environmental diversity: Two stories from Mesolithic Norway

This paper explores environmental variations in time and space, adaptive strategies and possible cultural responses to climatic changes as manifested through archaeological data in terms of lithic tool technology, site density and settlement patterns. The objective is investigated by two case studies from Mesolithic Norway. The first case deals with the earliest settlement phase of Norway (c. 11,500–10,000 cal. BP), which climatically encompasses gradual changes from cold, arctic conditions, to a milder sub-arctic climate, as well as the rapid Preboreal Oscillation (PBO) cold event. The second case explores the 8200 cal. BP cold event and its effect on culture and settlement in Southeast Norway.The studies suggest that the coastal settlement, in terms of site density, was not affected by either the PBO or the 8200 cal. BP event. Changes in site location patterns seem to have occurred gradually and on a long-term scale. Shifts in lithic technology are detected within the Mesolithic periods, but a correlation between abrupt climatic alterations and cultural changes are yet to be proved. We argue, therefore, that in these northern, coastal environments, declining temperatures may have had less impact than on the Continental Plains, and may in fact have improved the living conditions for a range of marine species. Also, the Mesolithic populations seemed to have employed a generalized lithic toolkit and a flexible mobility system – adaptive strategies that was able to withstand environmental variations in time and space.

The ecological niche and distribution of Neanderthals during the Last Interglacial

AbstractAimIn this paper, we investigate the role of climate and topography in shaping the distribution of Neanderthals (Homo neanderthalensis) at different spatial scales. To this end, we compiled the most comprehensive data set on the distribution of this species during the Last Interglacial optimum (MIS 5e) available to date. This was used to calibrate a palaeo‐species distribution model, and analyse variable importance at continental and local scales.LocationEurope and Irano‐Turanian region (20° N to 70° N, 10° W to 70° E).MethodsWe used archaeological records and palaeoclimatic and topographic predictors to calibrate a model based on an ensemble of generalized linear models fitted with different combinations of predictors and weighted background data. Area under the curve scores computed by leave‐one‐out were used to assess variable importance at the continental scale, while local regression combined with recursive partition trees was used to assess variable importance at the local scale.ResultsAnnual rainfall and winter temperatures were the most important predictors at the continental scale, while topography and summer rainfall defined habitat suitability at the local scale. The highest habitat suitability scores were observed along the Mediterranean coastlines. Mountain ranges and continental plains showed low habitat suitability values.Main conclusionsThe model results confirmed that abiotic drivers played an important role in shaping Neanderthals distribution during the Last Interglacial. The high suitability of the Mediterranean coastlines and the low suitability values of most sites at the northern and eastern distribution limits (Germany, Hungary, Ukraine) challenge the notion of Neanderthals as a species with preference for colder environments.

MANIFESTO OF THE SOUTH AMERICAN SCHOOL OF (ACTUALISTIC) TAPHONOMY

When the young Charles Darwin explored the Atlantic coast of southern South America, he was impressed by its fossils—as he wrote in the first paragraph of the Origin of Species (1859)—and the magnitude of its “wide and desolate” plains (Darwin 1839, p. 124). Although his adventures on the Patagonian plains became more famous, Darwin’s first observations were on the Pampas, a flat area that covers parts of Argentina, Brazil and Uruguay, where the gaucho was lord and master. Since that time, these flat lowlands have been the object of much geological and paleontological research, but there is still much more to discover, especially in the field of taphonomy. South America is particularly suited to test taphonomic ideas thanks to the recent geological evolution of the area, associated with sea level oscillations since the Pleistocene, which left numerous lagoons and estuaries along the coast. In fact, the Patos Lagoon (Brazil) and Rio de La Plata (Uruguay and Argentina) are the largest lagoon and one of the largest estuaries in the world, respectively, providing vast areas of diverse shallow coastal environments. In the terrestrial realm, southern Argentina is characterized by fluvial systems originating in the high Andes Cordillera as well as numerous permanent and temporary lakes due to the gentle slope of the plain. In addition to a diverse array of marine and terrestrial environments, exposures of fossiliferous accumulations from continental shelf, coastal plain, and freshwater basin settings provide exceptional opportunities for comparing modern death assemblages with fossil counterparts. Thanks in part to this profusion of “natural taphonomy laboratories”, actualistic taphonomy in South America is experiencing a period of exciting growth and advancement. Studies on the southern Brazilian continental shelf have focused on the comparative taphonomy of bivalved mollusks and brachiopods (Kowalewski et al. 2002; Carrol et al. 2003; Rodland et al. 2004 …

Animal evolution and atmospheric pO2: is there a link between gradual animal adaptation to terrain elevation due to Ural orogeny and survival of subsequent hypoxic periods?

Considering evolution of terrestrial animals as something happening only on flat continental plains seems wrong. Many mountains have arisen and disappeared over the geologic time scale, so in all periods some areas of high altitude existed, with reduced oxygen pressure (pO2) and increased aridity. During orogeny, animal species of the raising terrain can slowly adapt to reduced oxygen levels.This review proposes that animal evolution was often driven by atmospheric oxygen availability. Transitions of insect ancestors and amphibians out of water are here interpreted as events forced by the lack of oxygen in shallow and warm water during Devonian. Hyperoxia during early Carboniferous allowed giant insects to be predators of lowlands, forcing small amphibians to move to higher terrains, unsuitable to large insects due to reduced pO2. In arid mountainous habitats, ascended animals evolved in early reptiles with more efficient lungs and improved circulation. Animals with alveolar lungs became the mammalian ancestors, while those with respiratory duct lungs developed in archosaurs. In this interpretation, limb precursors of wings and pneumatised bones might have been adaptations for moving on steep slopes.Ural mountains have risen to an estimated height of 3000 m between 318 and 251 Mya. The earliest archosaurs have been found on the European Ural side, estimated 275 Myr old. It is proposed that Ural orogeny slowly elevated several highland habitats within the modern Ural region to heights above 2500 m. Since this process took near 60 Myr, animals in these habitats fully to adapted to hypoxia.The protracted P-Tr hypoxic extinction event killed many aquatic and terrestrial animals. Devastated lowland areas were repopulated by mammaliaformes that came down from mountainous areas. Archosaurs were better adapted to very low pO2, so they were forced to descend to the sea level later when the lack of oxygen became severe. During the Triassic period, when the relative content of O2 reduced to near 12%, archosaurs prevailed as only animals that could cope with profound hypoxia at the sea level. Their diverse descendants has become dominant terrestrial animals, until the K-Pg extinction due to meteor impact.Electronic supplementary materialThe online version of this article (doi:10.1186/1742-4682-11-47) contains supplementary material, which is available to authorized users.

Hydrogeochemical and isotopic characterisation of groundwater in a sand-dune phreatic aquifer on the northeastern coast of the province of Buenos Aires, Argentina

This contribution presents the hydrochemical and isotopic characterisation of the phreatic aquifer located in the Partido de la Costa, province of Buenos Aires, Argentina. In the sand-dune barrier geomorphological environment, groundwater is mainly a low-salinity Ca-HCO3 and Na-HCO3-type, being in general suitable for drinking, whereas in the continental plain (silty clay sediments), groundwater is a Na-Cl type with high salinity and unsuitable for human consumption. The general isotopic composition of the area ranges from−6.8 to−4.3 ‰ for δ18O and from−39 to−21 ‰ for δ2H, showing that rainwater rapidly infiltrates into the sandy substrate and reaches the water table almost without significant modification in its isotopic composition. These analyses, combined with other chemical parameters, made it possible to corroborate that in the eastern area of the phreatic aquifer, there is no contamination from marine salt water.