ASM Poster cd jk ma
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Distribution and Biodiversity of Tardigrades (Water bears) in the Grand Canyon National Park
Jesse Kerr, Michaela Alvers, Samuel Brown, Burnett Grant, Stephanie Lewis, Dave Ginocchio and Dr. Clarissa Dirks, The Evergreen State College
The phylum Tardigrada consists of upwards of 900 species of microscopic organisms famously known as the only animals able to survive the vacuum and radiation of space,. Tardigrades can be found in marine, freshwater, and semi-‐terrestrial environments living on moss and lichen. Our project aims to better understand how these organisms are dispersed and the role of abiotic factors in this process. We investigated the distribution and biodiversity of tardigrades in the Grand Canyon National Park (GCNP) in relation to a variety of abiotic factors including elevation, geologic strata, and moisture content of an environment. Of the few tardigrade diversity studies conducted in Arizona, our study was the first research endeavor examining tardigrades in the GNCP.
0% 10% 20% 30% 40% 50% 60% 70%
1900-2900
2900-3900
3900-4900
4900-5900
5900-6900
6900-8000
Elevation (ft)
% Samples with Live Tardigrades by Elevation
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
% DRY Samples Positive % Wet Samples Positive
Percentage of Samples with Live Tardigrades
Figure 2: Left: The Grand Canyon from Grandview Point. The Terrain is characteristic
more likely to have no tardigrades.
Introduction
Bryophyte samples were collected from seven different trails along both the north rim and south rim of the GCNP spanning a range of elevation from 1900 ft. to 8000 ft. Samples were characterized as either (desert) or , high moisture samples from seeps and springs. From each sample site, GPS location, geologic strata, and a description of the microhabitat was recorded. In the laboratory, samples were uniformly prepared, measured, weighed, and dried to determine moisture content and moss volume. Tardigrades were isolated by conventional moss sieving. Abundance data from other meiofauna including nematodes, rotifers, microcilliaphora, and moss ticks were recorded simultaneously.
Methods
Results
Live tardigrades were found in a much higher proportion of the
(desert) samples (n=70) than the high moisture samples (n=28) (those collected from seeps and springs. (Fig 2)
Live tardigrades were also found to be unevenly distributed by elevation. (Fig 3) The lowest elevations sampled (between 1900-‐3900 feet), and the highest elevations sampled (between 6900 -‐ 8000 feet) were least likely to contain live tardigrades. Samples were more likely to contain tardigrades between 3900 6900 feet. The elevation band that contained the highest percentage of samples with live tardigrades was between 3900-‐4900 feet.
Determine tardigrade species using morphological and molecular methods.
Phase contrast and differential interference contrast (DIC) microscopy using the Zeiss Universal Compound Microscope. PCR amplification of cytochrome oxidase subunit 1 (CO1) for DNA barcoding
Analyze distribution of species in relation to abiotic factors. Characterize possible undiscovered species by light and SEM microscopy.
Conclusions Tardigrade Distribution by Moisture Content
Tardigrade Distribution by Elevation
Tardigrade Distribution by Geologic Strata
Acknowledgements
Tardigrades were more likely to be found in naturally low moisture samples in the GNCP. Elevations between 3900-‐6900 feet in the GNCP were more likely to contain tardigrades. Geological layers composed of limestone and sandstone were more likely to contain live tardigrades than those composed of shale.
Future Directions
This project was funded by grants from the Betty Kutter Fund, the Foundation Activity Grant, (of The Evergreen State College Foundation) , and the Student Undergraduate Research Fund. Support was provided by the Scientific Instructional technicians of TESC, (Ladd Rutherford, Trisha Towanda, Alberto Napuli, Dan Cygnar, and others. Special thanks to John McClain
Figure 4 : Buccal-‐pharyngeal apparatus of Macrobiotus sp. Imagedat 400X with Light Microscopy (LM)
Figure 5: Preliminary results of a 658 bp PCR amplified CO1 from five tardigrades , negative control, post-‐ -‐product, and 1kb DNA ladder
The percentage of samples with live tardigrades was influenced by the geological strata, or layer, the sample was collected from (Fig. 4). Strata composed primarily of shale (Hakatai and Bright Angel) were less likely to contain live tardigrades than those composed of limestone or sandstone (Muav, Redwall, Coconino, and Kaibab). The Supai Group (composed of both limestone and sandstone) and Redwall Limestone were most likely to contain live tardigrades.
Not examined
Not examined
Kaibab Formation Toroweap Formation Coconino Sandstone
Supai Group
Redwall Limestone
Muav Limestone
Tapeats Sandstone Bright Angel Shale
Hakatai Shale
0%10%20%30%40%50%60%70%
Kaibab
Toroweap
Coconino
Supai
Redwall
Muav
Bright Angel
Tapeats
Hakatai
Figure 1: The method. A of moss of
standardized width is suspended in the bottom of a conical tube and an ice cube is melted over it. The resulting is then examined for tardigrades and other meiofauna. This process is repeated twice.
Figure 3: Tardigrade Distribution by Elevation
Figure 4: Tardigrade Distribution by Geological Layer: Geological layers were composed of shale, limestone, sandstone, or igneous/ metamorphic rock (some data not shown).