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Inland waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional pre-aged (Holocene and late-Pleistocene) carbon released from thawing permafrost soils, but the magnitude of these source contributions to total inland water carbon fluxes remains unknown. Here we present unique simultaneous radiocarbon age measurements of inland water CO2, CH4 and dissolved and particulate organic carbon in northeast Siberia during summer. We show that >80% of total inland water carbon was contemporary in age, but pre-aged carbon contributed >50% at sites strongly affected by permafrost thaw. CO2 and CH4 were younger than dissolved and particulate organic carbon, suggesting emissions were primarily fuelled by contemporary carbon decomposition. Our findings reveal that inland water carbon emissions from permafrost landscapes may be more sensitive to changes in contemporary carbon turnover than the release of pre-aged carbon from thawing permafrost.

Dynamic energy budget (DEB) theory provides a framework for quantifying metabolic processes and biological rates. DEB models have been widely applied to aquaculture species, but this type of model has great potential for application to fisheries for stock assessment and enhancement. The shrimp Fenneropenaeus chinensis, widely distributed along the coast of China and Korea, is the most important fisheries and aquaculture species in China. With the AmP method, DEB parameters were estimated for the population along the coast of China. The parameter estimation achieved an overall goodness of fit with MRE of 0.131 and SMSE of 0.178. In comparison with similar species, the values of a few main parameters are relatively high including reserve capacity (Em), somatic maintenance (ṗM) and allocation fraction to growth and somatic maintenance (κ). This may reflect an adaptation to variation of environmental conditions. The model can predict the physiological behaviours including respiration, ammonia excretion and feeding rates reasonably well. It shows overall capability to predict the growth and reproduction with acceptable confidence in three main geographic regions. There are clear differences between the female and male with much faster growth rate of the former. Validations of the model have shown that it can adequately predict growth of the shrimp in both its natural distribution waters and land-based culture systems. This study provides important information for further development of modeling tools which can contribute to estimating the carrying capacity for stock enhancement and optimizing production from integrated multi-trophic aquaculture.