首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Dust provenance and its role as a potential fertilizing agent for the Okavango Delta,Botswana
Authors:Marc S Humphries  Claudia R Benitez-Nelson  Michael Bizimis  Timothy J Ralph  Zacchary T Larkin  Terence S McCarthy
Institution:1. School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa;2. School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, USA;3. Department of Environmental Sciences, Macquarie University, Sydney, NSW, Australia;4. School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
Abstract:Dust plays a globally important role in supplying biologically essential elements to landscapes underlain by nutrient-poor substrates. Here we show that dust may play a significant role in sustaining productivity in the vast wetlands of the Okavango Delta in southern Africa, one of the world's richest biodiversity hotspots. Dust accumulates preferentially on tree-covered islands in the seasonal swamps of the Delta, creating pockets of fine-grained, nutrient-rich material within the semi-arid landscape of the Kalahari Desert. Strontium and neodymium isotopes reveal that this dust likely originates predominantly from the Makgadikgadi salt pans, located 300 km away, and contributes 10–80% of the fine-grained material present in Okavango island soils. Surface material sourced from the Makgadikgadi Pans contains relatively high amounts of bioavailable phosphorus and iron, potentially influencing Okavango Delta biological productivity. We propose that long-term ecosystem productivity and nutrient availability in the Okavango may be strongly mediated by regional dust inputs. Understanding the influence of dust deposition on nutrient loads and biogeochemical cycling is thus critical for predicting the response of the Okavango Delta to future changes in climate. We suggest that dust inputs may play a significant role in the supply of nutrients to other large, global wetland systems located in dryland environments. © 2020 John Wiley & Sons, Ltd
Keywords:dust transport  Kalahari Desert  Makgadikgadi  nutrient enrichment  Okavango Delta  radiogenic isotopes  wetlands in drylands
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号