1. Identifying Zooplankton Communities in Southeastern Estuaries and Reservoirs
Meg Danish, S.E. Bennett, Melissa Pompilius and Dr. Robert U. Fischer
MTSU CBAS Department of Biology
Daphnia lumholtzi and native Daphnia species were monitored at 8 sites along
the Alabama Mobile- Tensaw Delta system and Weeks Bay National Estuary
monthly for 2 years. Native species and D. lumholtzi were detected at all sites.
Using light microscopy and sem, we have determined that there are 5 native
species in our sites. It appears that there are more species present in the Delta
system than in reservoirs. Additionally, D. lumholtzi is present in all sites
except the Weeks bay estuary.
Compare which species in reservoirs & estuary system
DNA barcoding is underway to confirm species identity
Lagerspetz, Kari YH. "Thermal avoidance and preference in Daphnia magna." Journal of Thermal Biology 25.6 (2000): 405-410.
East, Therese L., et al. "Daphnia lumholtzi and Daphnia ambigua: population comparisons of an exotica and a native cladoceran in Lake Okeechobee, Florida." Journal of Plankton Research 21.8 (1999):
1537-1551.
DeVries, Dennis R., Russell A. Wright, and Tammy S. DeVries. "Daphnia lumholtzi in the Mobile River Drainage, USA: Invasion of a Habitat That Experiences Salinity." (2006): 527-530.
Kolar, Cynthia S., and David H. Wahl. "Daphnid morphology deters fish predators." Oecologia 116.4 (1998): 556-564.
Kivivuori, Liisa A., and Eila O. Lahdes. "How to measure the thermal death of Daphnia? A comparison of different heat tests and effects of heat injury." Journal of thermal Biology 21.5 (1996): 305-311.
Daphnia lumholtzi’s presence over multiple years indicates that it is established
in the Alabama Delta system as an NIS. Additionally Dlumholtzi is present in
all sites except the Weeks bay estuary.
It appears that there are more native species present in the Delta system than in
reservoirs.
DNA barcoding is underway to confirm morphological identifications.
Background Preliminary Results
Conclusions
Bibliography
The authors would like to thank
would like to thank many wonderful individuals for their invaluable
contributions and tireless efforts.
Acknowledgments
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Further Information
LogoLogo Abstract #Abstract #
Globalization of human activities has led to the
introduction of non-indigenous invasive species (NIS)
in nearly all aquatic ecosystems in the U.S.
One NIS that is generating increasing interest is the
subtropical zooplankton Daphnia lumholtzi.
Our lab is interested in monitoring the presence of this
NIS in relation to native Daphnia species.
Historically, Daphnia have been identified using
various morphological keys. Although D. lumholtzi is
readily identifiable due to its unique morphology, it is
often difficult to positively identify native species due
to their very similar morphological traits.
Recently, DNA barcoding has become a widely used
method for molecular confirmation of species identity.
We have been using microscopy to develop region-
specific morphological keys for Daphnia found in our
sites.
These keys will be combined with DNA barcode data
to establish a rapid means of monitoring Daphnia
species diversity in field populations.
Fig.1. A simplified
representation of the
role of Daphnia in
the food web.
Materials and Methods
Zooplankton samples were
collected monthly from sites
throughout the Mobile-Tensaw
delta that range from estuarine to
freshwater, including swamps,
lakes and springs. Two reservoir
sites along the Tennessee-
Tombigbee Waterway that feeds
into the Delta were also surveyed.
Samples were collected by
vertical hauls through the entire
water column using a 253 micron
Wisconsin plankton net.
Compound and stereo light
microscopes were used to take
digital images of anatomical
characters and soft tissues for
identification.
Scanning electron microscopy
was used to obtain images of
characters too ambiguous to
identify via light microscopy.
Purpose
Because Daphnia species are often difficult to distinguish morphologically, our goal was to 1) create a set
of morphological image keys specific to the species found in our field sites, and 2) validate a set of DNA
barcode primers that can be used to confirm species identity. These tools will be used to simplify species
identification in our field populations.
3. Proximal, middle, and distal pecten of
postabdominal claw same size
ID: D. parvula
1. Swimming hair
at bottom of
second segment
extends past tip
of ramus
2. Ocellus present
1. Ocellus present; according to morphology
key, should be inconspicuous or absent.
DNA barcoding needed to confirm identity.
2. Middle pecten of postabdominal claw larger
than proximal and distal pecten, but not more
than twice their length.
ID: D. ambigua
ID: D. lumholtzi
1. High pointed helmet
2. Long, widely-
spaced ventral
spines (more
prominent on
juvenile as shown)
3. Prominent neck fornices
4. Mating graspers (males only)
DNA barcoding is a molecular method of
differentiating species using the
mitochondrial CO1 gene. In animals, the
CO1 gene mutates at a characteristic rate,
which makes delineation between species
possible. Specimens are collected, DNA
is extracted and sequenced, and results
are compared to a database conforming
to Barcode of Life Initiative standards
for identification. The ultimate goal of
DNA barcoding is to create a
consolidated, free online database to be
used for taxonomic research.
Table 1: Presence of native vs. invasive Daphnia species at specified sites

2. Mobile-Tensaw Delta Weeks Bay Estuary Tenn-Tom Reservoirs
D. ambigua
D. laevis
D. lumholtzi
D. parvula
D. pulex
D. rosea

3. Key
Verified presence Presence suspected, not verified
Key
Presence verified
Presence suspected,
not verified

4. 3
4

5. 2
1

6. 2

7. 1