A Tale of Two FloodsReflections on Biological Sustainability Regina Linder (bio) Keywords Biodiversity, climate change, horizontal gene transfer (HGT), microbial genetics, microbiome, narrative power, Noah's Ark, Superstorm Sandy, zoonosis INTRODUCTION1 In May 2019, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), an internationally funded U.N.-backed group, prepared a report summarizing thousands of biodiversity studies. IPBES found that, in addition to the twenty percent of Earth's plant and animal life that have disappeared over the past century, as many as one million ADDITIONAL plant and animal species are at risk of extinction.2 The causes the authors cite for this loss of habitats are all driven by human activity: a doubling of the human population in the last fifty years, increased food production, overfishing, global trade, and climate change. As the pandemic caused by COVID-19 continues, further investigations have identified interactions among climate, biodiversity, and the development of pathogenic microorganisms as a further threat capable of widespread human harm.3 Writing in response to the 2019 IPBES report, New York Times climate reporter Brad Plumer reflected upon both the practical toll such a loss would take on society as well as the consequences of the disappearance of the "spiritual or inspirational value" of nature, "[which] can be difficult to quantify."4 Our oldest stories confirm the essential relationship between human well-being and the preservation of natural environments and their inhabitants. Flood stories from Asia, Australia, the Americas, and the Near East—including the biblical story of Noah—can be found throughout ancient literature. In the Huxley Memorial Lecture of 1916, anthropologist James Frazer described these narratives as "contemporary [End Page 406] folklore."5 Reframing these myths as chronicles about microbial diversity had personal resonance for me as a scientist who studies microorganisms. Applying current knowledge of molecular biology to past floods—mythological or otherwise—is impossible. Today, however, we have the necessary tools to explore the biological, cultural, and emotional impact of catastrophic weather events on human communities. What do we mean when we talk about the loss of life forms? How can we interpret the observations of our ancient ancestors through a lens of contemporary molecular biology? Taxonomic or ecological change, especially among microbial species, can be explained by physical/chemical changes and/or transfer of nucleic acid (DNA and RNA) between organisms. Such events may take place in environments like water or within organisms themselves. How does contemporary scientific knowledge inform our ideas and subjective reactions to the natural losses we experience? Examples that emerge from a more recent flood story help to make the ancient ones accessible. These and similar narratives exercise a unique influence on human imagination, linking science with the sense of loss underlying ecological damage.6 FLOOD STORIES ACROSS TIME AND CULTURES The image of a paternal Noah, shepherding pairs of animals onto the ark he designed to protect them from forty days of rain, is beloved by children across cultures. Best known from the biblical Genesis story, this narrative forms the basis of the Islamic, Christian, and Jewish interpretations of the flood event, which respectively portray Noah as a prophet, a righteous preacher, or an ordinary man heeding God.7 However, the Abrahamic narratives were long preceded by "deluge" or flood stories in Near Eastern literature. Mesopotamian Gilgamesh poems (2100–2000 BC) and the Babylonian Atrahasis Epic that followed tell of a flood hero with characteristics of a god but relate logistical details very similar to the Genesis chronicle.8 Historians believe these stories are precursors of the biblical version, transmitted by the people of Haran, the region from which the Patriarch Abraham would emerge.9 All versions of the story agree that the destruction of the earth by water resulted from human failing, including violence and corruption.10 In the aftermath of the deluge, it can be argued that a new and more modern order emerges. Lifespans no longer reach the exceptional 1000 years that Noah achieves, as future Patriarchs and Matriarchs typically live about one tenth of that. Much commentary is devoted to the description of [End Page 407] Noah as a "good man in his day" and whether or not...