EGU23-10354, updated on 26 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Floral analysis of a ~140 yr sediment record using sedaDNA and diatoms, Summit Lake Nevada, USA

Paula Noble1,2, Sarah Crump3,4, Amelia Muscott4, Darren Larsen5, Ana Carolina Ruiz Fernandez6, Sudeep Chandra2,7, James Simmons8, Ayowole Fifo1, and Adam Csank9
Paula Noble et al.
  • 1Geological Sciences & Engineering, University of Nevada,Reno, United States of America (
  • 2Global Water Center, University of Nevada Reno, United States of America
  • 3Ecology and Evolutionary Biology, University of California Santa Cruz, United States of America
  • 4Geology and Geophysics, University of Utah, Salt Lake City, United States of America
  • 5Geology, Occidental College, Los Angeles, United States of America
  • 6Instituto de Ciencias del Mar y Limnología, UNAM, Mazatlán, Mexico
  • 7Biology, University of Nevada Reno, United States of America
  • 8Natural Resources Department Summit Lake Paiute Tribe, Sparks Nevada, United States of America
  • 9Geography, University of Nevada Reno, United States of America

The sediment fill at Summit Lake shows strong potential for reconstructing past changes (Holocene to present) in the paleoecology and regional paleoclimate for the subalpine region of the Black Rock Range, northwestern Nevada, USA. Summit Lake is a high desert terminal lake with a surface elevation of 1780m.a.s.l. and is a eutrophic, alkaline (~8.4), dimictic lake with a maximum depth of ~10 m and a small surface area (2.8 km2). There is abundant growth of macrophytes, including Polygonium (smartweed), Myriophyllum (milfoil), and Ceratophyllum (coon tail), and growth progresses throughout the summer months. The lake falls within the domain of the Summit Lake Paiute Tribe, who has an inextricable cultural connection to the lake via the native Lahontan cutthroat fishery. The tribe’s original name, Agai Panina Ticutta, translates as the Summit Lake Fish Eaters.

In 2021 and 2022 C.E., we collected a series of surface and long sediment cores from multiple sites in the lake. This study focuses on sediments collected from the lake’s central depocenter. Preliminary age control of Summit Lake sediments is determined by 210Pb-dating (corroborated by the stratigraphic profiles of the man-made radionuclides 137Cs, 241Am) for the upper ~40 cm, and the Mount Mazama tephra (~7.6 ka) at 410cm depth. The age model suggests high and increasing sedimentation rates between early 1900 C.E. and 2021 C.E. (from 0.05 to 1.87 cm/yr). In comparison, the mean sedimentation rate between the Mazama tephra and ~1900 C.E. is low (0.05 cm/yr). We present preliminary sedaDNA and diatom data for the last ca. 140 years. Plant sedaDNA shows good preservation, with a stable alpha diversity of ~40 ASVs. The plant record is dominated by the aquatic plants Myriophyllum and Potamogeton (pondweed) in the upper 40cm, and terrestrial plants are also represented, including sagebrush, willow, aspen, and a variety of herbaceous plants, including aster, rose, primrose, buckwheat, borage, lupin, and saxifrage. The diatom flora of the upper 40cm is dominated by the benthic epiphyte Cocconeis placentula, which is consistent with a large macrophyte community seen in the modern system and indicated by the plant sedaDNA. Modern sampling shows the epiphytic relationship between C. placentula and milfoil. Future work will include pairing and harmonizing the diatom record derived from traditional morphotaxonomy and eDNA, contextualizing the plant eDNA with the modern plant community, and refining the age model to better discern Holocene climate events that may be driving the changes in sediment flux and the floral community. These data will be extended down-core to reconstruct the past climate and lake levels, informing the Tribe’s management efforts for a resilient watershed and fishery in the future.

How to cite: Noble, P., Crump, S., Muscott, A., Larsen, D., Ruiz Fernandez, A. C., Chandra, S., Simmons, J., Fifo, A., and Csank, A.: Floral analysis of a ~140 yr sediment record using sedaDNA and diatoms, Summit Lake Nevada, USA, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10354,, 2023.