Yasuhara, MoriakiMoriakiYasuharaWei, Chih-LinChih-LinWeiKucera, MichalMichalKuceraCostello, Mark J.Mark J.CostelloTittensor, Derek P.Derek P.TittensorKiessling, WolfgangWolfgangKiesslingBonebrake, Timothy C.Timothy C.BonebrakeTabor, Clay R.Clay R.TaborFeng, RanRanFengBaselga, Andr?sAndr?sBaselgaKretschmer, KerstinKerstinKretschmerKusumoto, BuntarouBuntarouKusumotoStathes PaganisCHIH-LIN WEI2020-07-072020-07-072020https://scholars.lib.ntu.edu.tw/handle/123456789/509314A major research question concerning global pelagic biodiversity remains unanswered: when did the apparent tropical biodiversity depression (i.e., bimodality of latitudinal diversity gradient [LDG]) begin? The bimodal LDG may be a consequence of recent ocean warming or of deep-time evolutionary speciation and extinction processes. Using rich fossil datasets of planktonic foraminifers, we show here that a unimodal (or only weakly bimodal) diversity gradient, with a plateau in the tropics, occurred during the last ice age and has since then developed into a bimodal gradient through species distribution shifts driven by postglacial ocean warming. The bimodal LDG likely emerged before the Anthropocene and industrialization, and perhaps ∼15,000 y ago, indicating a strong environmental control of tropical diversity even before the start of anthropogenic warming. However, our model projections suggest that future anthropogenic warming further diminishes tropical pelagic diversity to a level not seen in millions of years. © 2020 National Academy of Sciences. All rights reserved.[SDGs]SDG13article; biodiversity; climate change; foraminifer; fossil; ice age; industrialization; last glacial maximum; nonhuman; planktonic foraminifera; sea; species distribution; tropics; warming; animal; physiology; plankton; sediment; tropic climate; Animals; Biodiversity; Climate Change; Fossils; Geologic Sediments; Plankton; Tropical Climatejournal article10.1073/pnas.1916923117