Der Beitrag nachhaltiger Raumentwicklung zur großen Transformation: Impulse für neue Strategien

Vor dem Hintergrund des Gutachtens "Welt im Wandel - Gesellschaftsvertrag für die Große Transformation" (Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen 2011) stellen die Autorinnen und der Autor die Frage nach dem Beitrag der Raumentwicklung und -planung zur großen Transformation mit dem Ziel einer nachhaltigen Raumentwicklung. Sie identifizieren sowohl Forschungs- als auch Handlungsbedarfe, indem sie Modelle, Strategien und Instrumente räumlicher Planung kritisch auf ihre Transformationspotenziale hin prüfen. Sichtbar wird so ein eklatanter Kommunikations- und Kooperationsbedarf. Dieser besteht zwischen den räumlichen Ebenen sowie zwischen räumlicher Planung bzw. Raumentwicklung und Politik, aber auch zwischen dem gestaltenden Staat und der Bürgerschaft bzw. Zivilgesellschaft und der Wirtschaft. Die aktuellen sozial-ökologischen Krisensituationen und die damit verbundenen gesellschaftlichen Herausforderungen zwingen in steigendem Maße dazu, neue Bewertungen im Sinne einer nachhaltigen Raumentwicklung vorzunehmen und einen Perspektivwechsel in Raum- und Planungswissenschaften sowie in der Planungspraxis einzuleiten. Das vorliegende Positionspapier basiert auf dem Forschungsbericht 15 der ARL (2021), in dem die Ergebnisse des Arbeitskreises "Nachhaltige Raumentwicklung für die große Transformation" dokumentiert sind

Seasonal dynamics and exports of elements from a first‐order stream to a large inland lake in Michigan

Headwater streams are critical components of drainage systems, directly connecting terrestrial and downstream aquatic ecosystems. The amount of water in a stream can alter hydrologic connectivity between the stream and surrounding landscape and is ultimately an important driver of what constituents headwater streams transport. There is a shortage of studies that explore concentration–discharge (C‐Q) relationships in headwater systems, especially forested watersheds, where the hydrological and ecological processes that control the processing and export of solutes can be directly investigated. We sought to identify the temporal dynamics and spatial patterns of stream chemistry at three points along a forested headwater stream in Northern Michigan and utilize C‐Q relationships to explore transport dynamics and potential sources of solutes in the stream. Along the stream, surface flow was seasonal in the main stem, and perennial flow was spatially discontinuous for all but the lowest reaches. Spring snowmelt was the dominant hydrological event in the year with peak flows an order of magnitude larger at the mouth and upper reaches than annual mean discharge. All three C‐Q shapes (positive, negative, and flat) were observed at all locations along the stream, with a higher proportion of the analytes showing significant relationships at the mouth than at the mid or upper flumes. At the mouth, positive (flushing) C‐Q shapes were observed for dissolved organic carbon and total suspended solids, whereas negative (dilution) C‐Q shapes were observed for most cations (Na+, Mg2+, Ca2+) and biologically cycled anions (NO3−, PO43−, SO42−). Most analytes displayed significant C‐Q relationships at the mouth, indicating that discharge is a significant driving factor controlling stream chemistry. However, the importance of discharge appeared to decrease moving upstream to the headwaters where more localized or temporally dynamic factors may become more important controls on stream solute patterns.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149221/1/hyp13416.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149221/2/hyp13416_am.pd

Parallel Evolution of a Type IV Secretion System in Radiating Lineages of the Host-Restricted Bacterial Pathogen Bartonella

Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens. Furthermore, our study highlights the remarkable evolvability of T4SSs and their effector proteins, explaining their broad application in bacterial interactions with the environment

Production of dust by massive stars at high redshift

The large amounts of dust detected in sub-millimeter galaxies and quasars at high redshift pose a challenge to galaxy formation models and theories of cosmic dust formation. At z > 6 only stars of relatively high mass (> 3 Msun) are sufficiently short-lived to be potential stellar sources of dust. This review is devoted to identifying and quantifying the most important stellar channels of rapid dust formation. We ascertain the dust production efficiency of stars in the mass range 3-40 Msun using both observed and theoretical dust yields of evolved massive stars and supernovae (SNe) and provide analytical expressions for the dust production efficiencies in various scenarios. We also address the strong sensitivity of the total dust productivity to the initial mass function. From simple considerations, we find that, in the early Universe, high-mass (> 3 Msun) asymptotic giant branch stars can only be dominant dust producers if SNe generate <~ 3 x 10^-3 Msun of dust whereas SNe prevail if they are more efficient. We address the challenges in inferring dust masses and star-formation rates from observations of high-redshift galaxies. We conclude that significant SN dust production at high redshift is likely required to reproduce current dust mass estimates, possibly coupled with rapid dust grain growth in the interstellar medium.Comment: 72 pages, 9 figures, 5 tables; to be published in The Astronomy and Astrophysics Revie