Variations of the stable isotopic compositions of rainfall events from the Cameroon rain forest, Central Africa

Njitchoua, R.; Sigha-Nkamdjou, L.; Dever, L.; Marlin, Christelle; Sighomnou, D.; Nia, P.

doi:10.1016/s0022-1694(99)00087-6

Cited by 71 publications

(64 citation statements)

References 17 publications

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“…4, 5) may be attributed to changing conditions at the source of atmospheric moisture (Ingraham 1998;Gonfiantini et al 2001) and local climatic effects such as re-evaporation (Taupin et al 2000;Liu et al 2014). The observed slopes are similar to those reported across Cameroon (Njitchoua et al 1999;Gonfiantini et al 2001;Fantong et al 2010;Ketchemen-Tandia et al 2013;Wirmvem et al 2014;Kamtchueng et al 2015) and elsewhere in the tropics (Mbonu and Travi 1994;Gonfiantini et al 2001;Sánchez-Murillo et al 2013, 2016Rai et al 2013). The generated local meteoric water lines are useful in assessing the origin and mechanism of groundwater recharge in both localities.…”

Section: Conventional Dsupporting

confidence: 84%

“…5 is in agreement with the so-called amount effect, i.e., the greater the volume of rainfall, the lower the d 18 O or dD content (Dansgaard 1964;Coplen et al 2000). The amount effect, which is a characteristic of tropical low-latitude precipitation (Dansgaard 1964), have also been observed in Cameroon (Njitchoua et al 1999;Kuitcha et al 2012;Wirmvem et al 2014;Kamtchueng et al 2015), western Africa (Mbonu and Travi 1994;Taupin et al 2000;Risi et al 2008;Adomako et al 2015), East Africa (Kebede and Travi 2012), Costa Rica (Sánchez-Murillo et al 2013) and the Bhagirathi River Basin in India (Rai et al 2013). …”

Section: That Dsupporting

confidence: 79%

“…The Atlantic Ocean moisture results in continental precipitation with d-excess close to 10 % (Dansgaard 1964). However, in hydrological systems where moisture recycling plays a significant role, higher d-excess values ([10 %) have been reported (Salati et al 1979;Gat and Matsui 1991;Sánchez-Murillo et al 2013;2016;Liu et al 2014) including the Cameroon rainforest (Njitchoua et al 1999;Kuitcha et al 2012;Ketchemen-Tandia et al 2013). During evaporation, d-excess decreases in residual moisture and will accordingly increase in the evaporated moisture such that precipitation from such moisture will be characterized by high d-excess (Salati et al 1979).…”

Section: Spatial Variation In Stable Isotopes and Moisture Recyclingmentioning

confidence: 99%

“…4b) representing the typical two rainy and dry seasons during a hydrological year in Yaounde. The annual V-shaped isotopic patterns in precipitation during each hydrological year are typical of precipitation in Cameroon (Njitchoua et al 1999;Wirmvem et al 2014;Kamtchueng et al 2015) and across the entire western Africa (Taupin et al 2000). In this section, the isotopic patterns have been used to describe the annual evolution of the regional precipitation cycle.…”

Section: Enriched Wdmentioning

confidence: 99%

“…They are also useful in climatological studies including the study of atmospheric moisture circulation (Njitchoua et al 1999;Taupin et al 2000;Bony et al 2008;Risi et al 2008). Few studies in the region including the Douala and Yaounde urban cities have reported the significance of continental recycled moisture to precipitation and evidence of the amount effect (Njitchoua et al 1999;Taupin et al 2000;Risi et al 2008;Kuitcha et al 2012;Ketchemen-Tandia et al 2013;Wirmvem et al 2014). However, an in-depth analysis of the relationship between isotopic variations in rainfall and the known regional annual cycle of precipitation has not been appraised.…”

Section: Introductionmentioning

confidence: 99%

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Variation in stable isotope ratios of monthly rainfall in the Douala and Yaounde cities, Cameroon: local meteoric lines and relationship to regional precipitation cycle

et al. 2016

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Section: Conventional Dsupporting

confidence: 84%

Section: That Dsupporting

confidence: 79%

Section: Spatial Variation In Stable Isotopes and Moisture Recyclingmentioning

confidence: 99%

Section: Enriched Wdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variation in stable isotope ratios of monthly rainfall in the Douala and Yaounde cities, Cameroon: local meteoric lines and relationship to regional precipitation cycle

et al. 2016

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A moisture budget perspective of the amount effect

Moore

Kuang

Blossey

2014

Geophysical Research Letters

110

109

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A stable water isotopologue-enabled cloud-resolving model was used to investigate the cause of the amount effect on the seasonal (or longer) time scales. When the total water (vapor and condensed phase) budget of the precipitating column of air is considered, our results indicate that as convection becomes stronger and the precipitation rate increases, the D of precipitation ( D p ) depends on the isotopic composition of the converged vapor more than that of surface evaporation. Tests with disabled fractionation from rain evaporation demonstrate that this mechanism does not account for the amount effect as has been previously suggested. If the isotopic content of converged vapor is made uniform with height with a value characteristic of surface evaporation, the amount effect largely disappears, further supporting the dominance of converged vapor in changes to the D p signal with increasing precipitation. D p values were compared to the water budget term E P , where P is precipitation and E is evaporation. Results from this comparison support the overall conclusion that moisture convergence is central in determining the value of D p and the strength of the amount effect in steady state.

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Trans‐Atlantic slavery: Isotopic evidence for forced migration to Barbados

Schroeder

O’Connell

Evans

et al. 2009

American J Phys Anthropol

115

111

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The question of the ultimate origin of African slaves is one of the most perplexing in the history of trans-Atlantic slavery. Here we present the results of a small, preliminary isotopic study that was conducted in order to determine the geographical origin of 25 enslaved Africans who were buried at the Newton plantation, Barbados, sometime between the late 17th and early 19th century. In order to gain a more nuanced understanding of the slaves' origin, we used a combination of carbon, nitrogen, oxygen, and strontium isotope analyses. Carbon and nitrogen isotope ratios were determined in bone and dentinal collagen; oxygen and strontium isotopes were measured in tooth enamel. Results suggest that the majority of individuals were born on the island, if not the estate itself. Seven individuals, however, yielded enamel oxygen and strontium ratios that are inconsistent with a Barbadian origin, which strongly suggests that we are dealing with first-generation captives who were brought to the island with the slave trade. This idea is also supported by the fact that their carbon and nitrogen stable isotope values differ markedly between their teeth and bones. These intra-skeletal shifts reflect major dietary changes that probably coincided with their enslavement and forced migration to Barbados. While it is impossible to determine their exact origins, the results clearly demonstrate that the slaves did not all grow up in the same part of Africa. Instead, the data seem to suggest that they originated from at least three different areas, possibly including the Gold Coast and the Senegambia.

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Variations of the stable isotopic compositions of rainfall events from the Cameroon rain forest, Central Africa

Cited by 71 publications

References 17 publications

Variation in stable isotope ratios of monthly rainfall in the Douala and Yaounde cities, Cameroon: local meteoric lines and relationship to regional precipitation cycle

Variation in stable isotope ratios of monthly rainfall in the Douala and Yaounde cities, Cameroon: local meteoric lines and relationship to regional precipitation cycle

A moisture budget perspective of the amount effect

Trans‐Atlantic slavery: Isotopic evidence for forced migration to Barbados

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