Dust provenance and its role as a potential fertilizing agent for the Okavango Delta, Botswana
Dust provenance and its role as a potential fertilizing agent for the Okavango Delta, Botswana
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DOI：
10.1002/esp.4840
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发表时间：
2020-02
影响因子：
3.3
通讯作者：
M. Humphries;C. Benitez‐Nelson;M. Bizimis;T. Ralph;Z. Larkin;T. McCarthy
中科院分区：
文献类型：
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作者：
M. Humphries;C. Benitez‐Nelson;M. Bizimis;T. Ralph;Z. Larkin;T. McCarthy
灰尘在为营养贫乏的基质提供生物必需元素方面发挥着全球重要作用。在这里，我们展示了尘埃可能在维持非洲南部奥卡万戈三角洲广阔湿地的生产力方面发挥重要作用，这是世界上生物多样性最丰富的热点之一。在三角洲季节性沼泽的树木覆盖的岛屿上，灰尘优先积聚，在喀拉哈里沙漠半干旱的景观中形成了细颗粒、营养丰富的物质口袋。锶和钕同位素显示，这些尘埃可能主要来自300公里外的Makgadikgadi盐田，并贡献了奥卡万戈岛土壤中10-80%的细颗粒物质。来自Makgadikgadi pan的表面物质含有相对较高的生物可利用磷和铁，可能影响奥卡万戈三角洲的生物生产力。我们认为，奥卡万戈的长期生态系统生产力和养分有效性可能受到区域粉尘输入的强烈调节。因此，了解粉尘沉积对养分负荷和生物地球化学循环的影响对于预测奥卡万戈三角洲对未来气候变化的响应至关重要。我们认为，粉尘输入可能在向位于旱地环境中的其他大型全球湿地系统提供养分方面发挥重要作用。©2020 John Wiley & Sons, Ltd
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