INVESTIGATING PLANKTON
PLANKTON
INVESTIGATING
IN AQUATIC
AQUATIC ECOSYSTEMS
ECOSYSTEMS
IN
BY
Nancy Biegel
2013 CMARS Teachers. Photo by Kathy Richardson.
www.owrb.ok.gov
academics.smcvt.edu
INTRODUCTION
The largest species in the ocean depend on the
smallest for their survival. The base of any aquatic
food web begins with those microscopic drifters, the
plankton. Made up of free-floating organisms and
weak swimmers, plankton move with the ocean
currents and tides.
The phytoplankton, or microscopic plants, harvest
the Sun’s energy to make food and oxygen. The
microscopic animals, or zooplankton, feast on the
phytoplankton and are in turn, eaten by larger and
larger organisms. Without plankton, there would be
no life in aquatic ecosystems.
WHAT IS PLANKTON?
The miniature world of plankton can be divided into
three groups, phytoplankton, zooplankton and
bacteria. Each has a niche in aquatic ecosystems.
projects.cwi.nl
IMPORTANCE OF PLANKTON
COPEPODS
An important consumer of phytoplankton, copepods
are tiny crustaceans and are the most numerous
multicellular animal on Earth. They are a critical link
between the autotrophs and the larger organisms in
aquatic food webs.
“Plankton are among the most important organisms
on Earth, without which most life would die.”
~Life on an Ocean Planet
Plankton are critical to the health of the complex
food webs of all aquatic ecosystems. From oxygen
production to carbon fixation, and production of
food, plankton, the smallest of organisms, is the
organism we can’t live without, even on land.
commons.wikimedia.org
DIATOMS
Examine a sample of freshwater or saltwater and
chances are, you’ll see diatoms. They are the
most dominant and efficient phytoplankton in any
aquatic environment. They have cell walls called
frustules which are made of silica. This allows light
to pass through which is ideal for photosynthesis.
www.in-fisherman.com
In aquatic ecosystems bacteria have the important
job of decomposition. They feed on the remains of
dead organisms, breaking them down and returning
the nutrients back into a form plants can use.
Zooplankton and filter-feeders also feed on the
bacteria.
RESOURCES
• Textbook: Life on an Ocean Planet
www.theseashore.org.uk
www.teachoceanscience.net
FISH & SHELLFISH LARVAE
Many larger organisms, such as crabs, oysters, and
finfish, begin their lives as plankton. In the plankton
stage, they may look nothing like their adult forms.
• www.chesapeakebay.net
• education.nationalgeographic.com
• Background photo: www.coexploration.org
• Copepod photo: academics.smcvt.edu
CREST
Phytoplankton, single-celled plants,
are primary producers, or autotrophs.
They make their own food using light
energy and produce 50% of the
world’s oxygen, more than any other
organisms. One drop of water may
contain thousands of phytoplankton.
The
primary
consumers
of
phytoplankton, and a vital link for
larger organisms, are zooplankton.
Most are microscopic, but some,
like jellyfish, can be much larger.
Zooplankton includes single-celled
organisms, as well as fish &
shellfish larvae, copepods, jellyfish
and comb jellies.
Some are
herbivores,
while
others
are
predators.
COMMON ZOOPLANKTON
COMMON PHYTOPLANKTON
www.fiu.edu
www.microscopy-uk.org.uk
DINOFLAGELLATES
Another
common
phytoplankton
are
the
dinoflagellates. Most have two flagella to help
them move up and down in the water column. They
can be photosynthetic or parasitic, and a few can
even
produce
their
own
light,
called
bioluminescence. These unicellular organisms are
responsible for large algae blooms that happen
during warm summers in coastal areas.
eol.org
COCCOLITHOPHORES
These are an important source
of food for aquatic ecosystems.
Plates of calcium carbonate
make up their outer covering.
When the organism dies, the
plates contribute to ocean
sediments such as limestone.
Callinectes sapida - Blue crab zoae.
CREST-CISCEP (Center for the Integrated Study of Coastal
Ecosystem Processes) is a NSF grant funded program at
UMES aimed at exposing students, especially those from
under represented populations, to the marine sciences
through summer internships, paid undergraduate and
graduate level assistantships and K-12 outreach activities.
CREST-CISCEP creates an educational and financial pipeline
through which scientifically inclined students can travel as
far as a Ph.D.!
dnr.maryland.gov
Fish eggs.
ACKNOWLEDGEMENTS
climatesight.org
PROTOZOANS
Ciliates, radiolarians,
foraminiferans,
and
other species come in
different sizes and
shapes with special
adaptations that help
them stay afloat. Some
have
skeletons
of
silica while others are
made
of
calcium
carbonate .
earthdata.nasa.gov
www.chesapeakebay.net
CTENOPHORA & CNIDARIA
Comb jellies, the ctenophores
lack the stinging cells of the
cnidarians. Their cilia show a
rainbow effect when they
move, caused by diffraction.
The jellyfish, or cnidarians,
catch their prey with stinging
cells
called
nematocysts.
Both
phyla
are
weak
swimmers which puts them
with the plankton.
Dr. Andrea Johnson, CISCEP Associate Director
Dr. Paulinus Chigbu, CISCEP Director
Kerrie Bunting Program Coordinators
Christopher Daniels, CISCEP Boat Captain
Faculty Mentors:
Dr. Eric May
Dr. Patricia Goslee
Dr. Joseph Pitula
Dr. Yan Waguespack
Dr. Madhumi Mitra
And all of the students who assisted with the program.