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

The Benthic Geoecology Model Within The Modular System For Shelves And Coasts (MOSSCO)

The Modular System for Shelves and Coasts (MOSSCO) integrates physical, biological, chemical and geological models of shelves and coasts for the North Sea and Baltic Sea in an exchangeable way. The MOSSCO software forms a coupling framework for exchanging data and models, which distinguishes between physical domains (Earth System compartments such as the benthic and pelagic zone) and processes (such as benthic geochemistry, physical erosion and biological stabilization). Information exchange across physical domains with different grids and time steps are managed using the ESMF (Earth System Modelling Framework), whereas coupling of processes within individual modules is achieved using FABM (Framework for Aquatic Biogeochemical Models). This paper reports coupling of a newly developed benthic geoecology model to the MOSSCO framework. This new model incorporates the biological effects of macrofauna (the bivalve Tellina fabula is taken as an example) and microphytobenthos on erodibility and critical bed shear stress. The model is implemented in an object-oriented generic modular way so that it can be extended to any number of biological effects on the sediment transport for an arbitrary number of species. Finally, the application of the coupled model is demonstrated in simulation of a1D setup