Assessing the challenges and initiatives to increase women’s integration into science in Madagascar

We present here a commentary essay on the challenges and perspectives on the recruitment and retention of Malagasy women in STEM (Science, Technology, Engineering, and Mathematics). We base the essay on our personal experience as Malagasy women scientists and support the arguments with the responses of 60 Malagasy women scientists to an online survey that was shared among Malagasy scientists. We identified that the main causes for a limited number of Malagasy women in STEM relied upon traditional expectations and heavily ingrained cultural values. The situation becomes more complicated when accounting for familial constraints, financial constraints, and communication gaps between students and professors. This is obviously an unfortunate situation; however, there have been bridging-gap initiatives—financial, awareness to family pressure, and knowledge difference between senior and junior scientists—that should be continued to provide support to promising students and enhance STEM education as a tool for development in Madagascar. RésuméCet essai discute les défis et les perspectives dans le recrutement et le maintien des femmes citoyennes de Madagascar dans les sciences, la technologie, l’ingénierie et les mathématiques (STIM). Les arguments présentés sont basés sur nos expériences personnelles en tant que femmes scientifiques nées et ayant grandies à Madagascar. Ces arguments sont soutenus par des informations issues d’un sondage effectué en ligne auprès de 60 femmes scientifiques, s’identifiant elles-mêmes originaires de Madagascar. Les raisons pour lesquelles ces femmes sont peu nombreuses à participer activement dans les domaines des STIM à Madagascar sont liées à des contraintes traditionnelles et à des valeurs culturelles fortement ancrées depuis leur enfance. La situation se complique lorsqu’on tient compte des contraintes financières et des écarts de communication entre étudiants et professeurs. Si cette situation est évidemment regrettable, il existe cependant des initiatives visant à combler le fossé qui sont financières, ou qui s’inscrivent dans la sensibilisation à la pression familiale et à la différence de connaissances entre les scientifiques seniors et juniors. Ces encouragements devraient être poursuivis afin d'apporter un soutien aux étudiantes prometteuses et d'améliorer l'enseignement des femmes en STIM qui sont importantes pour le développement de Madagascar

Greenhouse gas emissions from African lakes are no longer a blind spot

peer reviewedNatural lakes are thought to be globally important sources of greenhouse gases (CO2, CH4, and N2O) to the atmo-sphere although nearly no data have been previously reported from Africa. We collected CO2, CH4, and N2O data in 24 African lakes that accounted for 49% of total lacustrine surface area of the African continent and covered a wide range of morphology and productivity. The surface water concentrations of dissolved CO2 were much lower than values attributed in current literature to tropical lakes and lower than in boreal systems because of a higher productivity. In contrast, surface water–dissolved CH4 concentrations were generally higher than in boreal sys-tems. The lowest CO2 and the highest CH4 concentrations were observed in the more shallow and productive lakes. Emissions of CO2 may likely have been substantially overestimated by a factor between 9 and 18 in African lakes and between 6 and 26 in pan-tropical lakes.AFRIVA

Evaluating model outputs using integrated global speleothem records of climate change since the last glacial

Although quantitative isotopic data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to use the speleothem data for data-model comparisons. Here, we illustrate this using 456 globally-distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates procuring large numbers of records if data-model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotopic values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model’s ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotopic data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on 18O values, the optimum period for the modern observational baseline, and the selection of an appropriate time-window for creating means of the isotope data for palaeo time slices

The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems

Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide “out-of-sample” evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (δ 18O, δ 13C) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data. The compiled data are available at https://doi.org/10.17864/1947.147

A unified English term that best reflect the people, the culture, and other things from Madagascar: 'Malagasy' instead of 'Madagascan'

Two words, Malagasy and Madagascan, have emerged in the literature as an English term to refer to the people, the culture, and other animate and inanimate objects from Madagascar, the choice of which has left room for confusions for users. This article has two aims: (1) understanding the sources of such confusions, and (2) subsequently proposing a unified English term (noun and adjective) that will avoid further misperceptions in written and verbal communications accounting for Madagascar. The results from investigating the Web of Science, from historical documents, and from viewpoints from online survey combine to suggest that the term 'Malagasy' must have unintentionally been substituted by the term 'Madagascan' from the earliest documented usage until now. These two words have been used interchangeably, and the usage has never been applied consistently. This could have been influenced by the simple assumption that 'Madagascan' is an intuitive form, derivative of Madagascar. However, 'Malagasy' is an irregular word and is unique to Madagascar, thus its usage as a word qualifier for different objects, animals, plants, and the people of Madagascar in the English language would suffice

Lavaka (erosional gullies) provide productive patch environments for flora and farming in Madagascar's grassy highlands

Societal Impact Statement Lavaka, large gullies in Madagascar, can cause problems for farmers and for infrastructure, but these features also have beneficial aspects that have generally been overlooked. They provide plant refugia, and commonly host species that would otherwise not thrive on the grassy uplands. Farmers sometimes make use of lavaka to plant crops that require more protection or soil moisture. Colonial narratives blame lavaka erosion on poor land management but ignore their pre‐human‐settlement existence on the landscape and the ecological functions they serve. The knowledge and wisdom of Malagasy farmers are key to better understanding the complex roles that lavaka plays in the landscape. Summary This paper combines a review of lavaka—erosional gullies in Madagascar's grass‐covered highlands—with new observations of their importance as ecological patch environments for a wide range of plants not seen elsewhere within the grassy biome. Lavaka play a role as a natural refugia for flora that would otherwise not thrive on the exposed and infertile hillslopes, and local farmers exploit their topography and sediment deposits to grow a variety of crops. We provide a classification scheme for lavaka based on the extent to which they have been colonised by vegetation. Our analysis is based on observations made over many field seasons in the highlands as well as interviews with Malagasy farmers living with lavaka on their land. We emphasise the importance of local knowledge and environmental wisdom in the analysis of landscape evolution, and we conclude that lavaka, while certainly an erosional problem in many places, can nonetheless provide valuable ecosystem services and agricultural opportunities that should not be overlooked

Triple oxygen isotope fractionation between CaCO3 and H2O in inorganically precipitated calcite and aragonite

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The African Humid Period, rapid climate change events, the timing of human colonization, and megafaunal extinctions in Madagascar during the Holocene: Evidence from a 2m Anjohibe Cave stalagmite

Stalagmite data from Anjohibe Cave in northwest Madagascar suggest six distinct climate periods from 9.1 to 0.94 ka. Periods I and II (9.1–4.9 ka) were wetter and punctuated by a series of prominent droughts. Periods IV-VI (4–0.94 ka) were much drier and less variable. Period III (4.9-4 ka) marks the transition between wetter and drier conditions and consists of two significant droughts: the first (4.8–4.6 ka) coincides approximately with the end of the African Humid Period and the second (4.3–4.0 ka) may be the expression of the Northern Hemisphere 4.2 ka dry event in northwest Madagascar. Strong positive correlations between δ13C and δ18O values in Periods I-IV (r = 0.63–0.91) suggest that both isotopes were influenced by natural climate changes indicating that humans may not have been present in the area. In contrast, during Periods V (r = 0.07) and VI (r = −0.12) the “decoupling” of δ13C and δ18O might signal an impact from human activities starting around 2.5 ka. Rapid changes in climate during the early and middle Holocene, with prominent droughts lasting up to 800 years, did not kill off Madagascar\u27s megafauna, and neither did a human population, present since the early Holocene if evidence from south Madagascar is reliable. However, many extinctions occurred under the more stable climatic conditions of the late Holocene, despite an antiphase climate relationship between northern and southcentral Madagascar. This suggests that initial human colonization, or significant increase in human population, triggered the megafaunal extinctions by hunting and destruction of megafaunal habitats

Layer-bounding surfaces in stalagmites as keys to better paleoclimatological histories and chronologies

Petrographic recognition of layer-bounding surfaces in stalagmites offers an important tool in constructing paleoclimate records. Previous petrographic efforts have examined thickness of layers (a possible proxy for annual rainfall) and alternation of layers in couplets (a possible indicator of seasonality). Layer-bounding surfaces, in contrast, delimit series of layers and represent periods of non-deposition, either because of exceptionally wet or exceptionally dry conditions. Two types of layer-bounding surfaces can be recognized according to explicitly defined petrographic criteria. Type E layer-bounding surfaces are surfaces at which layers have been truncated or eroded at the crest of a stalagmite. Keys to their recognition include irregular termination of layers otherwise present on the stalagmite\u27s flank, dissolutional cavities, and coatings of non-carbonate detrital materials. Type E surfaces are interpreted to represent wet periods during which drip water became so undersaturated as to dissolve pre-existing stalagmite layers, and thus they necessarily represent hiatuses in the stalagmite record. Type L layer-bounding surfaces are surfaces below which layers become thinner upward and/or layers have lesser lateral extent upward, so that the stalagmite\u27s layer-specific width decreases. They are thus surfaces of lessened deposition and are interpreted to represent drier conditions in which drip rate slowed so much that little deposition occurred. A Type L surface may, but does not necessarily, represent a hiatus in deposition. However, radiometric age data show that Type L surfaces commonly represent significant hiatuses. These surfaces are significant to paleoclimate research both for their implications regarding climate change (exceptionally wet or dry conditions) and in construction of chronologies in which other data, such as stable isotope ratios, are placed. With regard to climate change, recognition of these surfaces provides paleoclimatological information that can complement or even substitute for geochemical proxies. With regard to chronologies, recognition of layer-bounding surfaces allows correct placement of hiatuses in chronologies and thus correct placement of geochemical data in time series. Attention to changing thickness of annual layers and thus to accumulation rate can also refine a chronology. A chronology constructed with attention to layer-bounding surfaces and to changing layer thickness is much more accurate than a chronology in which hiatuses are not recognized at such surfaces

Main controls on the stable carbon isotope composition of speleothems

The climatic controls on the stable carbon isotopic composition (d13C) of speleothem carbonate are less often discussed in the scientific literature in contrast to the frequently used stable oxygen isotopes. Various local processes influence speleothem d13C values and confident and detailed interpretations of this proxy are often complex. A better understanding of speleothem d13C values is critical to improving the amount of information that can be gained from existing and future records. This con- tribution aims to disentangle the various processes governing speleothem d13C values and assess their relative importance. Using a large data set of previously published records we examine the spatial imprint of climate-related processes in spe- leothem d13C values deposited post-1900 CE, a period during which global temperature and climate data is readily available. Additionally, we investigate the causes for differences in average d13C values and growth rate under identical climatic condi- tions by analysing pairs of contemporaneously deposited speleothems from the same caves. This approach allows to focus on carbonate dissolution and fractionation processes during carbonate precipitation, which we evaluate using existing geochem- ical models. Our analysis of a large global data set of records reveals evidence for a temperature control, likely driven by veg- etation and soil processes, on d13C values in recently deposited speleothems. Moreover, data-model intercomparison shows that calcite precipitation occurring along water flow paths prior to reaching the top of the speleothem can explain the wide d13C range observed for concurrently deposited samples from the same cave. We demonstrate that using the combined infor- mation of contemporaneously growing speleothems is a powerful tool to decipher controls on d13C values, which facilitates a more detailed discussion of speleothem d13C values as a proxy for climate conditions and local soil-karst processes.status: publishe