Naturgemalde

Portrait of Alexander Humboldt by Mathew
Brady. Image source.

Alexander von Humboldt was one of the most pioneering naturalists to have lived since the reformation. Celebrated by his colleagues and contemporaries across the world, he was widely esteemed by other well-known global figures including Charles Darwin, President Thomas Jefferson, and the poet Goethe. His is honored in the naming of counties, a major oceanic current, and other geographic features worldwide, but in the United States he is less well known than his fame and accomplishments deserve.

Humboldt’s life was largely unknown to me too until reading Andrea Wulf’s recent biography of Humboldt, The Invention of Nature, published in 2015. Wulf walked in the footsteps of this remarkable man, following the intellectual journey of Humboldt and the other naturalists and thinkers he influenced over the last two centuries. Humboldt was a true “renaissance” individual, a student of an astounding diversity of intellectual disciplines including geology, botany, mining, anthropology, mountaineering, and poetry. Because of his prominence in the development of the fields of natural history and ecology, his life’s story alone would be compelling enough for me, but my appreciation for him deepened when Wolf’s biography enlightened me to his forward-looking social views (including a life-long contempt for colonialism, and slavery). That connection to Humboldt felt even more personal when surmising from his decades of particularly close friendships with men and his lack of marriage that he was probably gay as well¹. As a citizen of science, Humboldt was intensely restless and unendingly curious, traits that I share too, though surely in much less abundance and with much less profit than Humboldt.

Born and raised in Prussia in the late 1700s in relative wealth and comfort, Alexander and his older brother were eased into the intellectual life. At a young age both brothers began to associate with local intellectual figures including Goethe. Humboldt’s formal education and training included university studies and eventually turned to mining as a specialization. Soon he embarked on his first major scientific employment as a mining inspector, traveling throughout northern Europe. He worked hard at his new career, and used his spare time in the evenings to conduct experiments. Nevertheless his true love was exploration and natural history, topics that fueled grand ambitions to travel widely. Departure from Europe to realize his dream wasn’t possible immediately however, because he felt an obligation to family expectations and because Europe was embroiled in an unfavorable political environment at the time.

Two of Humboldt’s scientific publications: Essay on the Geography of Plants (left) and a later edition of Views of Nature (right). Images from the Biodiversity Heritage Library.

After several years waiting to leave what felt like the stifling confines of Europe, a unique opportunity finally befell the young adventurer. Humboldt was given extraordinary freedom by the King of Spain to travel to and explore the vast Spanish territories of Central and South America. With a young French botanist Aimé Bonpland, he sailed from Spain in 1799 to cross the Atlantic. Humboldt was 30 years old at the time, beginning a five year journey that would transform both the individual and the field of natural history itself.

Humboldt and Bonpland’s famous South American expedition brought them through thick tropical jungles, to hot savannas, and to the towering icy volcanic peaks of the Andes. Along the way, the two mapped the landscape and explored. In one excursion, they confirmed the existence of a river rumored to connect the great tropical rivers of the South American rain forest, the Orinoco and Amazon. Heading further south, the team climbed many of the Andean peaks – active volcanoes included – and made almost a full ascent of Mt. Chimborazo, an imposing Andean peak which was then believed to be the tallest mountain in the world.

After extensive travels in the northwestern region of South America, the two explorers also spent time in Mexico, Cuba, and the United States. Along their remarkable journey, Humboldt and Bonpland collected thousands of plant and animal specimens and made meticulous meteorological observations with instruments they brought over from Europe. Humboldt studied ancient indigenous cultures, observed agricultural practices, discovered that the magnetic equator was some six degrees south of the geographic equator, met famous and ordinary people alike, and grew to know more about South America than any other Europeans alive at the time.

Humboldt and Bonpland’s diagram of the distribution of plants with elevation at Mt. Chimborazo in the Andes which appeared in Essay on the Geography of Plants. This detailed figure – which includes data on altitude, climate data, and even the heights to which previous mountaineers had ascended – may be ecology’s first infographic. Image source.

Humboldt returned to Europe and began to publish extensively on his travels, beginning an extensive writing career that would eventually cover a remarkably broad array of scientific topics. The South American journey would turn out to be the most significant expedition that Humboldt took in his life. His desire to travel didn’t wane after returning to Europe from South America, and though he would be denied his deep desire to journey to India, he traveled widely within Europe over the next few decades of life. During this period of his middle age, he lived most of the time in Paris, Berlin, and London, supported in part by a royal stipend granted to him by the King of Prussia that funded his living expenses and publications. Humboldt notoriously failed to manage his finances well, concerning himself much more with science, travel, and publications. He lectured, wrote and received thousands of letters, met and conversed with the leading European scientists of the day, and was generous in supporting young scientists. He was an incessant talker and brash on occasion.

Detailed sections of Humboldt and Bonpland’s figure on the distribution of plants with altitude. The image includes hundreds of species and genus names including the Ericaceous shrub Vaccinium and grass Andropogon (at left), and, to my delight as an enthusiast of algae, the aquatic green algal genus Ulva (at right). Images from publications in Biodiversity Heritage Library.

The fruits of his travels in the Americas were bountiful, enabling many publications and advancing Humboldt to the highest intellectual circles in Europe. But he still wanted to see more. With India inaccessible (it was controlled by the Britian’s East India Company which probably didn’t like Humboldt’s outspokenly unfavorable disposition towards colonialism), he settled on a different adventure that would allow him to continue his study of mountains and confirm the patterns he had already observed in South America and Europe. At about age 60, decades after his South American travels, he embarked on a remarkable loop though Russia on a relatively speedy 8 month journey that covered over 10,000 miles. Relative to his South America expedition, he traveled in greater physical comfort, and with a larger crew of fellow scientists. This trip to the Urals, across Siberia, and to the Altai Mountains in central Asia provided confirmatory evidence for many of the scientific ideas he developed earlier. Though fruitful, in terms of length, biota, and intellectual freedom it could not overshadow the South American journey.

Humboldt’s wide ranging interests and tremendous intellectual capacity manifest throughout his life resulted in accomplishments in an astonishing array of fields. For instance, he wrote about the evolution of species, predating Darwin’s “Origin of Species” by decades (Darwin’s great accomplishment, aided by Wallace, was to piece together disparate lines of evidence to posit natural selection as the mechanism of evolution). He mused about a potential ancient connection between Africa and South America, hinting at the idea of the movement of crustal plates across the earth (plate tectonics), a key principle of modern geology that would not be widely accepted scientifically until 150 years later.

He dabbled in an astounding breadth of disciplines and never failed to impress even the most esteemed scientists of his day. One of his greatest talents was the ability to forge connections between disciplines and ideas, a holistic approach to science that was becoming increasingly rare even in his day when the tendency of scientists was to specialize and pursue reductionist approaches to studying the natural world. To Humboldt, everything in nature and human society was interconnected; mere catalogues of facts or collections of specimens inadequately captured that complexity and relationships.

Humboldt made profound advances in natural history, laying a solid foundation for the field of ecology that would more formally develop from natural history a century later. One of his greatest contributions was “naturgemälde”, a German concept that Wulf explains would roughly translate as “painting of nature”. Naturgemälde was Humboldt’s revolutionary way of depicting nature, a view that emphasized connection and unity between all of life and between life and the abiotic world. He saw the world as non-static and evolving, a key idea that underpins our modern understanding of astronomy, geology, evolution, and ecology.

One of the pivotal moments in the development of the holistic perspective of nature came to Humboldt as he scaled Chimborazo in the Andes. As he passed from the hot tropical forests that occurred at lower elevations to the cooler climate at greater heights, he observed how the flora changed with the ascent. From tropical species at the base of the mountain, the flora changed to finally consist of only lichens in the high alpine. As he climbed, he stopped periodically to make measurements of air pressure, temperature, and other variables. He thought of climate gradients throughout the world and what he knew of plant distributions in other geographic areas. Linking all of these facts, he made the connection between plant distributions and climate gradients, not just for Chimborazo but on a global scale. He would confirm his observations about the link between plants and climate in the Andes with observations in the Altai Mountains made during his travels of central Asia decades later.

Humboldt was the father of biogeography, inspiring the travels of other great naturalists including Charles Darwin and John Muir, both of whom traveled extensively prior to their literary accomplishments. Darwin and Muir both read Humboldt, the former marking his books with meticulous notes aboard the Beagle, and each longed to travel to South America in Humboldt’s footsteps.

A figure by William Woodbridge in 1823 dividing the world into climate zones based on temperature using isotherms. Humboldt invented isoclines, the concept of depicting data in two dimensions (e.g., a map) with lines that denote equal values of a parameter. Isoclines are used to show gradients of temperature (isotherms), barometric pressure (isobars), etc. Woodbridge used global temperature data gathered by Humboldt and others in his figure. Image source.

Humboldt made the connection between forests and ecosystem function, and he noted that a single species could affect an array of other species in an ecosystem. This insight came from observing that the palm trees that dominated the hot plains of the Llanos in Venezuela “spread life around it in the desert”. Humboldt was hinting at concepts that would later be termed “foundation species”, or “ecosystem engineer” by modern ecologists, the idea that one species provides the basis for an entire ecosystem (Dayton 1972, Jones et al. 1997).

In Humboldt’s worldview, humankind was also part of the fabric of nature, but often in negative ways. In both South America and in Russia, he saw the impact of poor agricultural practices on local ecosystems. He noted that deforestation raised local temperatures and decreased soil water capacity, making the vital connection between human effects on ecosystem and subsequent changes in climate at the local scale. He even presciently made this connection more generally, suggesting that the pollution humankind was emitting into the atmosphere could affect temperatures globally. The connections between climate, human activity, and ecosystems is of course one of the most profound environmental issues we face today.

Thanks to Wulf’s excellent biography, Humboldt is my newest intellectual hero and I’m eager to read some of his published work and to walk in his intellectual footsteps. He’s an excellent role model for thinking holistically, and of the ambition and creativity that move science forward.

Notes

1. As a social construct, “gay” or “lesbian” identities probably did not exist in the 18^th or 19^th century western world, but as a sexual and romantic orientation, non-heterosexuality has existed for thousands of years among diverse cultures worldwide. 

2. All images in this post are in the public domain.

References

Dayton PK. 1972. Toward an understanding of community resilience and the potential effects of enrichment to the benthos at McMurdo Sound, Antarctica. In: Proceedings of the Colloquium on Conservation Problems in Antarctica.

Jones CG, Lawton JH, Shachak M. 1997 Positive and negative effects of organisms as physical ecosystem engineers. Ecology 78:1946-1957.

Quammen D. 1996. The Song of the Dodo. Scribner, New York.

Wulf A. 2015. The Invention of Nature. Alexander von Humboldt’s New World. Vintage Books, New York.