by a science based on billions of data produced by methods that do not allow any return to the specimen, such as data from participatory sciences or metagenomics. The challenge is being able to produce knowledge without any traceability or possibility of revision or refutation, the opposite of what has been built over several centuries of natural history research. There is therefore an urgent need to find strategies for reconciling these different types of data, which some consider, respectively, as “quality data” versus “Big Data”.
Being able to re-examine objects and associated materials is thus an inseparable aspect of the research on collections and is therefore part of most of the studies in this book (for a broader overview, see Chapter 15 by Robuchon et al.). Nevertheless, the following three chapters illustrate this element of the research on collections well. The rediscovery of the blue diamond, one of the two extraordinary gems of Louis XIV, represents an excellent example in this respect. Stolen in 1792, this diamond was considered lost until very recently. Detailed analysis of a wealth of documentation, the rediscovery of a clay cast and the ability to examine the modified diamond after the theft have confirmed earlier hypotheses about its whereabouts, and also allowed the reconstruction of a zircon copy including many of its unique characteristics (see Chapter 3 by Farges).
The second example is the study of the Chachapoya mummy (see Chapter 4 by Thomas et al.). This artifact, which is part of the museum and scenic history of the Musée de l’Homme and which inspired one of the most remarkable paintings in the history of art of the late 19th and early 20th centuries – Edvard Munch’s The Scream – is now part of the history of modern science on Amerindian people. Recent studies and the use of new technologies have made it possible to examine the interior of the body and to understand how this people lived and the causes of their death.
The third example concerns new studies on human skulls, probably one of the most heavily examined artifacts in the history of science (see Chapter 5 by Friess and Galland). This study shows how new methods of 3D morphometry have provided new insights and contributed to a better understanding of important issues in the evolution of human diversity, including the relationship between skull shape and geographical distribution and linguistic diversity.
1.3.2. Collections at the heart of highly innovative research thanks to new technologies
Another aspect of innovative uses of collections is the importance of technologies to access information that could not be acquired before. Chapter 6 (by Invernón et al.) shows how a study of hyperaccumulators of metals and rare earths in herbarium plates was possible using X-ray fluorescence spectrometry. The results indicate how the herbarium can be used to identify not only useful species for the remediation of heavy metal contaminated sites but also to search for locations where the concentration of certain metals and rare earths may be significant. These fluorescence techniques as well as X-ray microtomography are also of great interest in the study of fossils, because they allow the visualization of structures invisible to the naked eye or through other traditional methods (see Chapter 7 by Charbonnier and Forel). Many diverse research are possible because of these new technologies (systematics, study of development or ancient paleogeography, etc.).
Another facet of the new questions and new technological possibilities is the creation of innovative collections. Collections that are initially intended to meet very specific demands open up a new universe of knowledge and experimentation. An excellent example is illustrated in Chapter 8 (by Duperron et al.) with the collection of live strains of cyanobacteria and microalgae, created to serve as a reference for ecotoxicological tests and environmental diagnostics. Duperron et al. show that this collection, in addition to its use in systematics, is of major interest in research facilitated by high-throughput “-omics” approaches. For example, it allows us to study the interactions between organisms, because the associated cyanosphere and phycosphere are preserved with the specimens. It also facilitates research into bioactive metabolites, mainly for pharmaceutical purposes, which are explored in an increasingly greater detail thanks to new technologies. Another example is presented in Chapter 9 (by Gerbault-Seureau and Dutrillaux) through the collections of cryopreserved cells and tissues of homeothermic vertebrates. This very rich, but still little exploited, collection represents an important source of cellular material, with its recent DNA and RNA of fibroblasts, available for research. Preserving tissues and cells of protected species is all the more interesting as these vulnerable species have small populations. Studies on living tissues of these species can be conducted repeatedly, after cell culture, without causing any harm to living individuals.
While cryopreserved cells and tissues do not enable the revival of homeothermic animals, seeds kept in natural history collections offer this possibility. Scientists have thus set themselves the goal of reviving extinct species whose seeds are preserved in the herbarium (see Chapter 10 by Muller et al.). This innovative approach obviously requires expertise in the reproductive physiology of the target species. This chapter therefore presents the first results of an ambitious project that is a precursor to a type of research that will probably become very widespread in the coming decades.
1.3.3. A resource for global change research
One of the major challenges in studying global change is establishing baselines from which we can see the magnitude and direction of ongoing changes. Global changes, and in particular climate change, are measured on time scales much longer than our contemporary observing systems that, for example, come from stations set up in the second half of the 20th century. Thus, studies on collections, whether paleontological, archaeological or current, seek to define and calibrate proxies to understand these changes.
Climate change research requires that these proxies be placed in the context of climate evolution over the last 20,000 to 100,000 years. In Chapter 11, Moreno and Bartolini demonstrate one such approach: the search for climate and salinity proxies in marine sediments (from a few tens of thousands of years ago to the last million years). This research is based on new collections of ocean cores, mainly from 1970 onwards. This chapter reveals the challenges inherent to the constitution and conservation, as well as to the analysis and understanding of data from such an extraordinary resource. In the same vein, Quiles et al. (Chapter 12) show how collections can provide access to atmospheric gas levels prior to a major landscape change. The aim is to calibrate the radiocarbon curve before the construction of the Aswan Dam in Egypt, which had a major impact on this region, and strongly affected the periodic flooding of the Nile. The analyses indicate that the herbarium plates of the 17th and 18th centuries allow for the detection of 14C levels in the atmosphere of this period. This study thus contributes to the refinement of archaeological dating over a historical period of several millennia, a major challenge for the knowledge of the history of ancient Egypt. These two projects reveal how collections can be at the heart of highly transdisciplinary research.
The next two chapters discuss research on the dispersal of crop pathogens and invasive alien species, problems associated with the globalization of agriculture and the transportation of diverse agricultural products over very long distances. The study by Gagnevin et al. (Chapter 13) explores the use of herbaria to study Xanthomonas citri pv. citri which infects citrus and geminiviruses that attack manioc and sweet potato. These pathogens have a strong impact on agricultural production in the Indian