| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | July 31, 2015 |
| Latest Amendment Date: | August 7, 2018 |
| Award Number: | 1516488 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Jonathan G Wynn
jwynn@nsf.gov (703)292-4725 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | August 1, 2015 |
| End Date: | July 31, 2021 (Estimated) |
| Total Intended Award Amount: | $253,265.00 |
| Total Awarded Amount to Date: | $253,265.00 |
| Funds Obligated to Date: |
FY 2016 = $73,718.00 FY 2017 = $42,461.00 FY 2018 = $18,989.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
2215 RAGGIO PKWY RENO NV US 89512-1095 (775)673-7300 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
2215 Raggio Parkway Reno NV US 89512-1095 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | INTEGRATED EARTH SYSTEMS |
| Primary Program Source: |
01001617DB NSF RESEARCH & RELATED ACTIVIT 01001718DB NSF RESEARCH & RELATED ACTIVIT 01001819DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The southern Great Basin is among the most arid regions in North America. It has almost no
perennial streams, but does have >1,000 springs. These springs are islands of aquatic habitat
in an ocean of desert. Remarkably, many of these isolated springs contain diverse aquatic
ecosystems and even endemic species of fish, spring snails, and other aquatic organisms. The
presence of many aquatic species that can only survive in water is evidence that the springs
are remnants of a perennial drainage system, and the presence of endemic species requiring
intervals in the million-year range for genetic divergence are evidence that at least some
of these springs have never desiccated over the geological time scale. Aquatic biogeographical
patterns thus inform the geological and hydrological history of the region.
This is a project to expand the already-large regional biogeographical database and to use the combined
new and preexisting data to test models of tectonic and paleohydrological evolution of the
southern Great Basin. The PIs will focus on two timescales: that of the extensional breakup of
the region from the late Miocene to the present and that of glacial/interglacial climate cycles.
Extensive work has been done to understand the extensional history of the region, which started
in the eastern portion of the study area at ~14 Ma and migrated westward to the Sierra Nevada
front, driven by plate-boundary dynamics. They will simulate this evolution using a regional
quasi-3D kinematic/tectonic-geomorphic-hydrologic coupled model that fully couples movement
along faults, mass distribution, magmatism, isostatic compensation and flexural deformation
with hydrology and surface geomorphic processes, including erosion and deposition. The extensional
fragmentation of the hydrological system will be studied and groundwater flow, necessary to
simulate the resulting development of springs, will be an integral part of the regional tectonic-geomorphic-hydrologic model.
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Modeled paleohydrologic histories will be tested against biotic data (aquatic biota inventories,
microbial and macrofaunal DNA, and genetic divergence times) with island biogeography theory.
The PIs will test for relations of hydrologic fragmentation chronology with endemic species and
for ecosystem diversity with spring resilience, as inferred from groundwater ages and climatically
driven modeling. They will use these results to assess and improve their tectonic/paleohydrologic models.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This is ther first study to integrate hydrogeology, geology, aquatic ecology across a broad landscape in a number of distictive conditions. Primary findings include:
1—Canonical correspondence analysis and structural equation modeling show that the structure of benthic acroinverterate (BMI) communities is most influenced by water chemistry. This is contrary to other aquatic systems where physical characteristics of the habitat is the strongest factor structuring BMI communities .
2—The structure of BMI communities differs between and among valleys and mountain ranges in the study area, and communities in each landscape are influenced by a distinctive suite of water chemistries.
3—BMI communities appear to be resilient to disturbance when it is within levels experienced over history and ancient times. Events such as drying have long term, consequential effects on aquatic communities in isolated desert systems.
4—There is a relationship between the percent of genetic difference of crenobionts (obligate spring dwelling organisms) from their ancestral forms showing that taxa with more ancient diversification occur in springs with higher groundwater resident times. This suggests that groundwater residence time is an indicator of aquatic habitat persistence.
5—There is a strong positive relationship between groundwater residence time and the number of crenobionts in a spring, suggesting that genetic diversification in these habitats is a function of the length of spring persistence that provides for long-term isolation of populations allowing them to differentiate from ancestral colonizers.
6— The timing of tectonic extension and the opening of drainages to the southeast in the southern Great Basin/Mojave Desert is coincident with colonization dates of Death Valley System endemic pupfish (Cyprinodon spp.) and springsnails (Pyrgulopsis spp.) as determined from mtDNA dating methods.
7— Island biogeography theory is inferred through the use of the DAISIE island biogeography model which can simulate biogeography and estimate parameters based on phylogenetic and phylogeographic data rather than a particular lineage. Model results show a clear break between the number of non-endemic and endemic taxa in study area springs roughly 3.5 ma, consistent with data collected in the study showing loss of fluvial connectivity. Once the loss of connectivity occurs, there is a sharp increase in the number of endemic species, as expected as springs become isolated and taxa begin to diverge increasing the number of endemic crenobionts.
Last Modified: 12/28/2021
Modified by: Donald Sada
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