Tropical-cyclone-driven erosion of the terrestrial biosphere from mountains.', Nature geoscience., 1 (11). pp. 759-762.Further information on publisher's website:The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. 10 11 The transfer of organic carbon from the terrestrial biosphere to the oceans via 12 erosion and riverine transport constitutes an important component of the global 13 carbon cycle 1-4 . More than one third of this organic carbon flux comes from 14 sediment-laden rivers that drain the mountains in the western Pacific region 3,5 . This 15 region is prone to tropical cyclones, but their role in sourcing and transferring 16 vegetation and soil is not well constrained. Here we measure particulate organic 17 carbon load and composition in the LiWu River, Taiwan, during cyclone-triggered 18floods. We correct for fossil particulate organic carbon using radiocarbon, and find 19 that the concentration of particulate organic carbon fromvegetation and soils is 20 positively correlatedwith water discharge. Floods have been shown to carry large 21 amounts of clastic sediment 6 .Non-fossil particulate organic carbon transported at 22

Here we assess earthquake volume balance and the growth of mountains in the context of a new landslide inventory for the M w 7.9 Wenchuan earthquake in central China. Coseismic landslides were mapped from high-resolution remote imagery using an automated algorithm and manual delineation, which allow us to distinguish clustered landslides that can bias landslide volume calculations. Employing a power-law landslide area-volume relation, we find that the volume of landslide-associated mass wasting ( 2.8 1 0.9/20.7 km 3 ) is lower than previously estimated ( 5.7-15.2 km 3 ) and comparable to the volume of rock uplift ( 2.6 6 1.2 km 3 ) during the Wenchuan earthquake. If fluvial evacuation removes landslide debris within the earthquake cycle, then the volume addition from coseismic uplift will be effectively offset by landslide erosion. If all earthquakes in the region followed this volume budget pattern, the efficient counteraction of coseismic rock uplift raises a fundamental question about how earthquakes build mountainous topography. To provide a framework for addressing this question, we explore a group of scaling relations to assess earthquake volume balance. We predict coseismic uplift volumes for thrust-fault earthquakes based on geophysical models for coseismic surface deformation and relations between fault rupture parameters and moment magnitude, M w . By coupling this scaling relation with landslide volume-M w scaling, we obtain an earthquake volume balance relation in terms of moment magnitude M w , which is consistent with the revised Wenchuan landslide volumes and observations from the 1999 Chi-Chi earthquake in Taiwan. Incorporating the Gutenburg-Richter frequency-M w relation, we use this volume balance to derive an analytical expression for crustal thickening from coseismic deformation based on an index of seismic intensity over a defined area. This model yields reasonable rates of crustal thickening from coseismic deformation (e.g., 0.1-0.5 km Ma 21 in tectonically active convergent settings), and implies that moderate magnitude earthquakes (M w 6-7) are likely responsible for most of the coseismic contribution to rock uplift because of their smaller landslide-associated volume reduction. Our first-order model does not consider a range of factors (e.g., lithology, climate conditions, epicentral depth, and tectonic setting), nor does it account for viscoelastic effects or isostatic responses to erosion, and there are important large uncertainties on the scaling relationships used to quantify coseismic deformation. Nevertheless, our study provides a conceptual framework and invites more rigorous modeling of seismic mountain building.

constrained. Here, we quantify POC source in the Mackenzie River, the main sediment 24 supplier to the Arctic Ocean 11,12 and assess its flux and fate. We combine measurements 25 1 Hilton, R. G., et al., Revised version for Nature, 12 th May 2015, doi:10. (Fig. 1). The δ 13 C org values and Al/OC total ratios support this inference (Extended Data Fig. 2). 92Using an end member mixing analysis 10,13 we quantify POC petro content of sediments matter turnover in terrestrial ecosystems is more rapid (Fig. 2c) with water discharge (Fig. 2b) could be important in setting the variability of POC biosphere age 123 carried by the river (Fig. 2c)

Mountain building results in high erosion rates and the interaction of rocks with the atmosphere, water and life. Carbon transfers that result from increased erosion could control the evolution of Earth's long-term climate. For decades, attention has focused on the hypothesised role of mountain building in drawing down atmospheric carbon dioxide (CO2) via silicate weathering. However, it is now recognized that mountain building and erosion affect the carbon cycle in other important ways. For example, erosion mobilises organic carbon (OC) from terrestrial vegetation, transferring it to rivers and sediments and thereby acting to draw down atmospheric CO2 in tandem with silicate weathering. Meanwhile, exhumation of sedimentary rocks can release CO2 through the oxidation of rock OC and sulfide minerals. In this Review we examine the mechanisms of carbon exchange between rocks and the atmosphere and discuss the balance of CO2 sources and sinks. Our Review demonstrates that OC burial and oxidative weathering, not widely considered in most models, control the net CO2 budget associated with erosion. Therefore, lithology strongly influences the impact of mountain building on the global carbon cycle, with an orogeny dominated by sedimentary rocks, and thus abundant rock OC and sulfides, tending towards being a CO2 source.

Connectivity describes the efficiency of material transfer between geomorphic system components such as hillslopes and rivers or longitudinal segments within a river network. Representations of geomorphic systems as networks should recognize that the compartments, links, and nodes exhibit connectivity at differing scales. The historical underpinnings of connectivity in geomorphology involve management of geomorphic systems and observations linking surface processes to landform dynamics. Current work in geomorphic connectivity emphasizes hydrological, sediment, or landscape connectivity. Signatures of connectivity can be detected using diverse indicators that vary from contemporary processes to stratigraphic records or a spatial metric such as sediment yield that encompasses geomorphic processes operating over diverse time and space scales. One approach to measuring connectivity is to determine the fundamental temporal and spatial scales for the phenomenon of interest and to make measurements at a sufficiently large multiple of the fundamental scales to capture reliably a representative sample. Another approach seeks to characterize how connectivity varies with scale, by applying the same metric over a wide range of scales or using statistical measures that characterize the frequency distributions of connectivity across scales. Identifying and measuring connectivity is useful in basic and applied geomorphic research and we explore the implications of connectivity for river management. Common themes and ideas that merit further research include; increased understanding of the importance of capturing landscape heterogeneity and connectivity patterns; the potential to use graph and network theory metrics in analyzing connectivity; the need to understand which metrics best represent the physical system and its connectivity pathways, and to apply these metrics to the validation of numerical models; and the need to recognize the importance of low levels of connectivity in some situations. We emphasize the value in evaluating boundaries between components of geomorphic systems as transition zones and examining the fluxes across them to understand landscape functioning. © 2018 John Wiley & Sons, Ltd.