Annette Summers Engel
Donald and Florence Jones Professor of Aqueous Geochemistry
University of Tennessee at Knoxville
Department of Earth and Planetary Sciences
Engel Lab Research -
Diversity and biogeochemical dynamics in lava tube ecosystems on the Big Island, Hawai'i
The Hawaiian Islands offer unparalleled opportunities for ecological studies in a well-defined evolutionary context. Hawai'i Island has the highest concentration of lava tubes and the greatest number of obligate, cave-adapted invertebrate species, currently at 49. However, there are significant knowledge gaps, including about cave biodiversity and distribution, evolutionary processes operating in these systems,  surface-subsurface connections, and about geochemical processes operating in the caves. 
 
Lava tube ecosystems rely on energy and nutrients sourced from mostly dead and live tree roots of overlying native forests, primarily comprised of the native 'Ōhi'a lehua tree (Metrosideros polymorpha). But, the fungi Ceratocystis spp. has started killing the 'Ōhi'a, and this rapidly spreading disease is reaching all areas of Hawai'i Island, known as Rapid 'Ōhi'a Death. 

This project focuses on describing the lava tube ecosystems in the Ka'ū district, specifically of the 42+-km-long Kipuka Kanohina Cave System (KKCS), located within the Hawaiian Ocean View Estates (HOVE). Caves outside of this system are also being explored. The KKCS formed in the Mauna Loa K3 lava flow unit, which dates to 750 – 1500 years before present, which means there is strong age constraint to study processes related to adaptation and speciation of macroinvertebrates in these caves. The purpose of the project is to understand the biodiversity, biogeography, and conservation needs for cave macroinvertebrate communities before the potential impacts of Rapid 'Ōhi'a Death.  

The research done in my lab, as part of this bigger project, focuses on the habitat geochemistry and ecology, and we are characterizing food web dynamics within these ecosystems using stable isotope systematics and geochemical modeling. 
Current support for this project, from the Cave Conservancy Foundation (to M.L. Porter & the Slays), as "Biodiversity, Biogeography, and Conservation of Unique Hawaiian Island Cave Communities"
 
PIs: 
Megan Porter   
University of Hawai’i-Mānoa
  
Christy Melhart Slay
The Sustainability Consortium 
University of Arkansas


Mike Slay   
Arkansas Field Office
The Nature Conservancy
 

Related Presentations from the Group

Slay, M.E., Porter, M.L., Slay, C., Engel, A.S. (2018) Preliminary results from a survey of lava tube caves in the southwest region of the Ka’ū district of the Big Island, Hawai'i. 24th International Conference on Subterranean Biology, 20-24 August 2018, ARPHA Conference Abstracts 1: e29874. https://doi.org/10.3897/aca.1.e29874

Engel, A.S., Porter, M.L., Slay, M.E., Slay, C.M. (2018) Fluids associated with deep roots in lava tubes and their food web implications. National Speleological Society Convention program, July 30–August 3, Helena, Montana.

Slay, C.A.M., Porter, M.L., Slay, M.E. (2017) Preliminary results from a survey of lava tube caves in the Southwest Region of the Ka’ū District of the Big Island, Hawai’i. National Speleological Society Convention program, June 19-23, Rio Rando, NM: 54.
    

  

Field Photographs

November 2017 Field Work - done with the assistance of local cavers from the Cave Conservancy of Hawai'i  and the Hawai'i Speleological Survey.
All photographs by Dr. Annette Summers Engel. 
March 2018 Field Work - done with the assistance of local cavers from the Cave Conservancy of Hawai'i  and the Hawai'i Speleological Survey.
All photographs by Dr. Annette Summers Engel. 
Geochemistry. Geomicrobiology. Geology. Ecology.

Interdisciplinary Research at the University of Tennessee