Disturbance and Climatic Drivers of Carbon Dynamics of a North Australian Tropical Savanna

2010 ◽  
pp. 97-116
Keyword(s):  
Carbon Dynamics ◽  
Tropical Savanna ◽  
Climatic Drivers

Management of soil physical health and carbon dynamics in maize cultivated field through organic amendments

2020 ◽  
Vol 52 (4) ◽  
Author(s):  
Haroon Shahzad ◽  
Muhammad Iqbal ◽  
Safdar Bashir ◽  
Muhammad Farooq
Keyword(s):  
Physical Health ◽  
Organic Amendments ◽  
Carbon Dynamics

Late-Holocene palaeoenvironmental reconstruction from a lake in the Amazon Rainforest-Tropical Savanna (Cerrado) boundary in Brazil using a multi-proxy approach

The Holocene ◽  
2021 ◽  
pp. 095968362110190
Author(s):  
Kury Milena Souza ◽  
Moreira Luciane Silva ◽  
Cordeiro Renato Campello ◽  
Sifeddine Abdelfettah ◽  
Turcq Bruno ◽  
...  
Keyword(s):  
Late Holocene ◽  
Amazon Region ◽  
Amazon Rainforest ◽  
Oxbow Lake ◽  
Tropical Savanna ◽  
Sedimentary Process ◽  
Climatic Fluctuations ◽  
Climate Conditions ◽  
Depositional Processes ◽  
Lake Formation

As an ecotone, the region between the Amazon Rainforest and Tropical Savanna (Cerrado) biomes is, by definition, more susceptible to climate change. Therefore, understanding palaeoenvironmental dynamics is essential to address the future responses of such transition areas to climatic fluctuations. In this context, we present a new sediment record for the Late-Holocene retrieved from Barro-Preto, currently an oxbow lake located in an ecotone at the southern Brazilian Amazon border. Our multi-proxy data include carbon and nitrogen isotopes, as well as bulk TOC, chlorophyll derivatives, grain-size and microcharcoal analyses, all anchored on a radiocarbon-dated chronology. The sedimentary process recorded at the Barro-Preto Lake responded to both local and regional climate dynamics. It was influenced by river excursions associated to local responses to precipitation changes by the activation of the palaeochannel connecting the main-stem river and the Barro-Preto lake. This activation was evidenced by the presence of different colour lithology laminations accompanied by coarser sediments and also by climate conditions known to influence the Amazon region. Depositional processes linked to lake dynamics and different oxbow lake cycle stages were also important to explain the changes verified in the Barro-Preto record, endorsing the use of this lake formation for palaeoclimatic reconstructions. The record indicated a rising humidity trend, reflected by a progressive increase in lacustrine productivity, in accordance to other studies carried out in the Amazon region concerning the Late-Holocene, associated with a more southward displacement of the Intertropical Convergence Zone. Despite this rising humidity trend, dry episodic events during the Late-Holocene were evidenced by charcoal data, also coherent with regional Amazon studies, albeit exhibiting increased intensity, suggesting that the transitional nature of the environment might have influenced susceptibility to fires.

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