48 research outputs found
Cultural and Demic Diffusion of First Farmers, Herders, and their Innovations Across Eurasia
Was the spread of agropastoralism from the Eurasian founder regions dominated
by demic or by cultural diffusion? This study employs a mathematical model of
regional sociocultural development that includes different diffusion processes,
local innovation and societal adaptation. Simulations hindcast the emergence
and expansion of agropastoral life style in 294 regions of Eurasia and North
Africa. Different scenarios for demic and diffusive exchange processes between
adjacent regions are contrasted and the spatiotemporal pattern of diffusive
events is evaluated. This study supports from a modeling perspective the
hypothesis that there is no simple or exclusive demic or cultural diffusion,
but that in most regions of Eurasia a combination of demic and cultural
processes were important. Furthermore, we demonstrate the strong spatial and
temporal variability in the balance of spread processes. Each region shows
sometimes more demic, and at other times more cultural diffusion. Only few,
possibly environmentally marginal, areas show a dominance of demic diffusion.
This study affirms that diffusion processes should be investigated in a
diachronic fashion and not from a time-integrated perspective.Comment: 9 pages, 3 figures, revised version submitted to Documenta
Prehistori
Bricks and urbanism in the Indus Valley rise and decline
The Indus Civilization, often denoted by its major city Harappa, spanned
almost two millennia from 3200 to 1300 BC. Its tradition reaches back to 7000
BC: a 5000 year long expansion of villages and towns, of trading activity, and
of technological advancements culminates between 2600 and 1900 BC in the
build-up of large cities, writing, and political authority; it emerges as one
of the first great civilizations in history. During the ensuing 600 years,
however, key technologies fall out of use, urban centers are depopulated, and
people emigrate from former core settlement areas. Although many different
hypotheses have been put forward to explain this deurbanization, a conclusive
causal chain has not yet been established. We here combine literature estimates
on brick typology, and on urban area for individual cities. In the context of
the existing extensive data on Harappan artifact find sites and put in their
chronological context, the combined narratives told by bricks, cities, and
spatial extent can provide a new point of departure for discussing the possible
reasons for the mysterious "decline".Comment: 11 pages, 3 figures, Supplementary Material. Submitted to PLOS On
The large scale impact of offshore wind farm structures on pelagic primary productivity in the southern North Sea
The increasing demand for renewable energy is projected to result in a
40-fold increase in offshore wind electricity in the European Union by 2030.
Despite a great number of local impact studies for selected marine populations,
the regional ecosystem impacts of offshore wind farm structures are not yet
well assessed nor understood. Our study investigates whether the accumulation
of epifauna, dominated by the filter feeder Mytilus edulis (blue mussel), on
turbine structures affects pelagic primary productivity and ecosystem
functioning in the southern North Sea. We estimate the anthropogenically
increased potential distribution based on the current projections of turbine
locations and reported patterns of M. edulis settlement. This distribution is
integrated through the Modular Coupling System for Shelves and Coasts to
state-of-the-art hydrodynamic and ecosystem models. Our simulations reveal
non-negligible potential changes in regional annual primary productivity of up
to 8% within the offshore wind farm area, and induced maximal increases of the
same magnitude in daily productivity also far from the wind farms. Our setup
and modular coupling are effective tools for system scale studies of other
environmental changes arising from large-scale offshore wind-farming such as
ocean physics and distributions of pelagic top predators.Comment: 17 pages, 6 figures, re-revised manuscript submitted to Hydrobiologi
Reconstituting human past dynamics over a landscape : pleading for the co-integration of both micro village-level modelling and macro-level ecological socio-modelling
International audienceThis communication tends to elaborate a plea for the necessity of a specific modelling methodology which does not sacrifice two modelling principles: explanation Micro and correlation Macro. Actually, three goals are assigned to modelling strategies: describe, understand and predict. One tendency in historical and spatial modelling is to develop models at a micro level in order to describe and by that way, understand the connection between local ecological contexts, acquired through local ecological data, and local social practices, acquired through archaeology. However, such a method faces difficulties for expanding its validity: It is validated by its adequacy with local data but the prediction step is unreachable and quite nothing can be said for places out where. On the other hand, building models at a far larger scale, for instance at the continent and even the world level, enhances the connection between ecology and its temporal variability. Such connections are based on well-improved theories but lower the " small causes, big effects " emergence corresponding to agent-based approaches and the related inherent variability of socio-ecological dynamics that one can notice at a lower scale: for instance, the emergence of social innovations can be simulated only as an input parameter. We then propose a plea for combining both elements for building large-scale modelling tools, which aims are to describe and provide predictions on long-term past evolutions, that include the test of explaining socio-anthropological hypotheses, i.e. the emergence and the spread of local social innovations
Modular System for Shelves and Coasts (MOSSCO v1.0) - a flexible and multi-component framework for coupled coastal ocean ecosystem modelling
Shelf and coastal sea processes extend from the atmosphere through the water
column and into the sea bed. These processes are driven by physical, chemical,
and biological interactions at local scales, and they are influenced by
transport and cross strong spatial gradients. The linkages between domains and
many different processes are not adequately described in current model systems.
Their limited integration level in part reflects lacking modularity and
flexibility; this shortcoming hinders the exchange of data and model components
and has historically imposed supremacy of specific physical driver models. We
here present the Modular System for Shelves and Coasts (MOSSCO,
http://www.mossco.de), a novel domain and process coupling system
tailored---but not limited--- to the coupling challenges of and applications in
the coastal ocean. MOSSCO builds on the existing coupling technology Earth
System Modeling Framework and on the Framework for Aquatic Biogeochemical
Models, thereby creating a unique level of modularity in both domain and
process coupling; the new framework adds rich metadata, flexible scheduling,
configurations that allow several tens of models to be coupled, and tested
setups for coastal coupled applications. That way, MOSSCO addresses the
technology needs of a growing marine coastal Earth System community that
encompasses very different disciplines, numerical tools, and research
questions.Comment: 30 pages, 6 figures, submitted to Geoscientific Model Development
Discussion
The Predominant Processes Controlling Vertical Nutrient and Suspended Matter Fluxes across Domains - Using the New MOSSCO System from Coastal Sea Sediments up to the Atmosphere
Integrated Modeling of Hydro-System
First Results of Modelling Benthos Influence on Sediment Entrainment Using a Generic Approach within the MOSSCO Framework
Sediment Transport and Morphodynamic
Global assessment of innovative solutions to tackle marine litter
AbstractMarine litter is one of the most relevant pollution problems that our oceans are facing today. Marine litter in our oceans is a major threat to a sustainable planet. Here, we provide a comprehensive analysis of cutting-edge solutions developed globally to prevent, monitor and clean marine litter. Prevention in this research includes only innovative solutions to prevent litter entering oceans and seas rather than interventions such as waste reduction and recycling. On the basis of extensive search and data compilation, our analysis reveals that information is dispersed across platforms and is not easily accessible. In total, 177 solutions—the equivalent to <0.9% of the search hits—fulfilled our validation criteria and were evaluated. Most solutions (n = 106, 60%) primarily address monitoring and were developed during the past 3 years, with the scientific community being the key driver. Few solutions reached mature technical readiness and market availability, while none were validated for efficiency and environmental impact. Looking ahead, we elaborate on the limitations of the existing solutions, the challenges of developing new solutions, and provide recommendations for funding schemes and policy instruments to prevent, monitor and clean marine litter globally. In doing so, we encourage researchers, innovators and policy-makers worldwide to act towards achieving and sustaining a cleaner ocean for future generations