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    

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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).