Summer-Wet Hydrologic Cycle during the Middle Miocene of the United States: New Evidence from Fossil Fungi

Jennifer M K O'Keefe¹, Matthew J Pound², Ingrid C Romero^{1

3}, Noelia B Nuñez Otaño^{4

5}, Martha E Gibson⁶, Jessica McCoy², Margaret E Alden¹, C Jolene Fairchild¹, Julia Fitzpatrick⁷, Emily Hodgson², Taylor Horsfall⁸, Savannah Jones⁸, June E Lennex-Stone¹, Christopher A Marsh¹, Alyssa A Patel⁸, Tyler M Spears¹, Laikin Tarlton⁷, Liberty F Smallwood⁷, O L VanderEspt⁹, Jeremyah R Cabrera⁸, Cortland F Eble¹⁰, William C Rember¹¹, James E Starnes¹², Mac H Alford¹³, Alyson Brink¹³, Sophie Warny¹⁴

Affiliations

¹ Department of Engineering Sciences, Morehead State University, Morehead, KY, USA.
² Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK.
³ Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
⁴ Laboratorio de Geología de Llanuras (CICYTTP- FCyT), CICYTTP (CONICET-Prov. ER-UADER), Diamante, Entre Ríos, Argentina.
⁵ CONICET (National Scientific and Technical Research Council), Buenos Aires, Argentina.
⁶ PetroStrat, Conwy, Wales, UK.
⁷ Department of Biology and Chemistry, Morehead State University, Morehead, KY, USA.
⁸ Craft Academy for Excellence in Science and Mathematics, Morehead State University, Morehead, KY, USA.
⁹ Department of Agricultural Science, Morehead State University, Morehead, KY, USA.
¹⁰ Kentucky Geological Survey, Lexington, KY, USA.
¹¹ Independent Researcher, Fernwood, ID, USA.
¹² Mississippi Department of Environmental Quality, Office of Geology, Jackson, MS, USA.
¹³ School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA.
¹⁴ Center for Excellence in Palynology, Department of Geology & Geophysics, and Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA.

PMID: 39319348
PMCID: PMC11420851
DOI: 10.34133/research.0481

Summer-Wet Hydrologic Cycle during the Middle Miocene of the United States: New Evidence from Fossil Fungi

Jennifer M K O'Keefe et al. Research (Wash D C). 2024.

. 2024 Sep 24:7:0481.

doi: 10.34133/research.0481. eCollection 2024.

Authors

Affiliations

¹ Department of Engineering Sciences, Morehead State University, Morehead, KY, USA.
² Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK.
³ Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
⁴ Laboratorio de Geología de Llanuras (CICYTTP- FCyT), CICYTTP (CONICET-Prov. ER-UADER), Diamante, Entre Ríos, Argentina.
⁵ CONICET (National Scientific and Technical Research Council), Buenos Aires, Argentina.
⁶ PetroStrat, Conwy, Wales, UK.
⁷ Department of Biology and Chemistry, Morehead State University, Morehead, KY, USA.
⁸ Craft Academy for Excellence in Science and Mathematics, Morehead State University, Morehead, KY, USA.
⁹ Department of Agricultural Science, Morehead State University, Morehead, KY, USA.
¹⁰ Kentucky Geological Survey, Lexington, KY, USA.
¹¹ Independent Researcher, Fernwood, ID, USA.
¹² Mississippi Department of Environmental Quality, Office of Geology, Jackson, MS, USA.
¹³ School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA.
¹⁴ Center for Excellence in Palynology, Department of Geology & Geophysics, and Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA.

PMID: 39319348
PMCID: PMC11420851
DOI: 10.34133/research.0481

Abstract

Hydrologic reconstructions from North America are largely unknown for the Middle Miocene. Examination of fungal palynomorph assemblages coupled with traditional plant-based palynology permits delineation of local, as opposed to regional, climate signals and provides a baseline for study of ancient fungas. Here, the Fungi in a Warmer World project presents paleoecology and paleoclimatology of 351 fungal morphotypes from 3 sites in the United States: the Clarkia Konservat-Lagerstätte site (Idaho), the Alum Bluff site (Florida), and the Bouie River site (Mississippi). Of these, 83 fungi are identified as extant taxa and 41 are newly reported from the Miocene. Combining new plant-based paleoclimatic reconstructions with funga-based paleoclimate reconstructions, we demonstrate cooling and hydrologic changes from the Miocene climate optimum to the Serravallian. In the southeastern United States, this is comparable to that reconstructed with pollen and paleobotany alone. In the northwestern United States, cooling is greater than indicated by other reconstructions and hydrology shifts seasonally, from no dry season to a dry summer season. Our results demonstrate the utility of fossil fungi as paleoecologic and paleoclimatic proxies and that warmer than modern geological time intervals do not match the "wet gets wetter, dry gets drier" paradigm. Instead, both plants and fungi show an invigorated hydrological cycle across mid-latitude North America.

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Conflict of interest statement

Competing interests: The authors declare that they have no competing interests.

Figures

**Fig. 1.**
Fungal study site ages and location. (A) Age of the 3 study sites plotted in relation to the δ18O “mega-splice” [2]. (B) Location of the 3 study sites within the United States. Blue shaded zone indicates Middle Miocene Climate Transition (MMCT), while pink shaded zone indicates Miocene Climate Optimum (MCO).

**Fig. 2.**
Fungal palynomorphs recovered from the Clarkia Konservat-lLagerstätte. (A) cf. *Bombardioidea*. (B) cf. Sordariales. (C) cf. *Brachydesmiella*. (D) cf. *Melanographium*. (E) *Sphaerodes*. (F) cf. Cercophora. (G) cf. *Polytretophora*. (H) *Hughesinia*. (I) cf. *Acrogenospora*. (J) cf. Apiosporaceae. (K) Xylariaceae. (L) cf. *Rosellinia*. (M) *Chaetomium*. (N) *Acarocybiopsis*. (O) *Endophragmia*. (P) *Bispora*. (Q) cf. *Didymosphaeria*. (R) *Neoroussoella*. (S) cf. *Lemkea*. (T) cf. *Catenularia*. (U) *Endophragmiella*. (V) *Desertella*. (W) *Bactrodesmium*. (X) *Spadicoides* sp. 1. (Y) *Spadicoide*s sp. 2. (Z) *Podospora*. (AA) *Minutisphaera*. (BB) *Pendulispora*. (CC) *Phragmocephala*. (DD) *Diporotheca* aff. *rhizophila*. (EE) *Melanocephala*. (FF) *Seychellomyces*. (GG) *Trichocladium*. (HH) *Brachysporiella*. (II) *Bactrodesmium* aff. *abruptum*. (JJ) *Endophragmiopsis*. (KK) *Naviculispora*. (LL) *Dictyocheirospora*. (MM) *Helensiella*. (NN) cf. *Helicoon*. (OO) cf. *Hermatomyces*. Scale bar, 10 μm.

**Fig. 3.**
Fungal palynomorphs recovered from Alum Bluff. (A) Glomeromycota. (B) *Acrogenospora*. (C) Apiosporaceae. (D) *Rosellinia*. (E) *Elegantimyces*. (F) *Atrotorquata* aff. *lineata*. (G) *Sporidesmium*. (H) *Savoryella* aff. *lignicola*. (I) *Minutisphaera*. (J) *Sphaerodes*. (K) cf. *Kionocephala*. (L) *Cercophora*. (M) *Spadicoides*. (N) Xylariales. (O) *Thecaphora*. (P) cf. *Hermatomyces*. (Q) *Canalisporium*. Scale bar, 10 μm.

**Fig. 4.**
Fungal palynomorphs recovered from the Bouie River site. (A) cf. *Catenularia*. (B) *Zopfiella* aff. *neogenica*. (C) cf. *Cercophora*. (D) *Spegazzinia* β-type. (E) cf. *Bahugada*. (F) *Sphaerodes*. (G) Sordariales. (H) *Chaetomium*. (I) cf. *Naviculispora*. (J) Apiosporaceae. (K) Xylariales. (L) cf. *Asterina*. (M) cf. *Delitschia*. (N) cf. *Berkleasmium*. (O) cf. *Rosellinia*. (P) cf. *Caryospora*. (Q) cf. *Endophragmiella*. (R) cf. *Diporotheca*. (S) cf. *Acrogenospora*. (T) cf. *Heteroconium*. (U) cf. *Melanocephala*. (V) *Termitariopsis*. (W) cf. *Bactrodesmium*. (X) cf. *Dictyosporium*. (Y) *Potamomyces.* Scale bar, 10 μm.

**Fig. 5.**
Funga-based Köppen-Geiger climate class reconstructions for (A) Clarkia, (B) Bouie River, and (C) Alum Bluff.

**Fig. 6.**
Comparison of (A) fossil plant and fossil funga-based Köppen-Geiger climate class reconstructions with (B) present-day distributions of Köppen-Geiger climate classes and (C) Köppen-Geiger climate class distributions predicted for 2071–2100 in the contiguous United States ([36]; Supplementary Materials, SI5).

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Summer-Wet Hydrologic Cycle during the Middle Miocene of the United States: New Evidence from Fossil Fungi

Affiliations

Summer-Wet Hydrologic Cycle during the Middle Miocene of the United States: New Evidence from Fossil Fungi

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

LinkOut - more resources

Full Text Sources

Research Materials