1. Lesson 17: Plankton Marine Biology
Note: The slide presentation and activity were created by Lisa Wu and Carol Lange. They are used and slightly modified with permission from the authors.

2. What exactly are plankton?
Plankton are weakly swimming or drifting organisms
“Plankton” is not a single species but a large
group of organisms that fall into two primary categories:
Phytoplankton (plants)
Zooplankton (animals)
3. Many are microscopic, some visible to the naked eye
Teacher’s Note:
1. You may want to point out to students that the line between ‘zooplankton’ and ‘phytoplankton’ is sometimes hard to distinguish. Especially in areas of the ocean that are not very productive, some types of plankton can be both heterotrophic and autotrophic.
2. Planktos (Greek) means to “wander”
3. Bacteria is another group of plankton but for simplicity, the main two groups are listed on the slide.

3. Classification of Plankton
Phytoplankton- are microscopic algae and other photosynthetic organisms
Zooplankton- are animals, mainly invertebrates that drift or swim weakly with the currents
Ichthyoplankton - comprise the larval fish component of the plankton.

4. Why are plankton important?
Important part of global carbon cycle
Food source (basis of the food web) for many other animals
Producer of oxygen (photosynthesis)

5. Photosynthesis primer
Recall from biology that autotrophs (aka primary producers) like plants or algae create carbohydrates (usable energy) from light through photosynthesis:
CO2 + H2O  C6H12O6 (carbohydrate) + O2(oxygen)
This energy supplies entire food webs as organisms are eaten up the food chain
Teacher’s Note: The diagram depicts autotrophs, also known as primary producers, converting light energy from the sun into carbohydrates (sugars) through photosynthesis. Heterotrophs cannot generate energy from solar or chemical sources, but must consume primary producers (and other heterotrophs) for energy. In this way, primary producers drive the food web.
Heterotrophs
(consumers)
Autotrophs
(primary
producers)
Sun
Plant/animal energy sources (carbohydrates)
Solar energy

6. Plankton are an energy source for marine ecosystems
Many plankton are primary producers
Over 90% of marine primary production (energy produced) is from phytoplankton! The rest is from marine plants and other sources.
This map shows
productivity in the
Oceans
Red and
yellow are most
productive, followed
by green and blue.
Black is least
productive.
Photo:
Accessed: November 2010
Photo: NOAA

7. How are plankton studied?
Collected with special nets
and sampling bottles
Underwater cameras
Microscopes
Satellites
Teacher’s Note: A bongo net is a metal frame with two paired mesh nets attached (see photo on slide). They are named “bongo nets” because they look somewhat like bongo drum. For more information, see: Accessed: November 2010.
A video plankton recorder is a form of underwater microscope that takes images of plankton for study while a boat is moving. The advantage is the ability to sample plankton quickly over a large area. For more information see: Accessed: November 2010.
Photo:
NOAA Photo Library
Image ID: fish1014, NOAA's Fisheries Collection Photo Date: 1987 Photographer: Captain Robert A. Pawlowski, NOAA Corps
Bongo nets may be towed over the side
of the ship to collect plankton.
Photo: NOAA

8. Satellites can also help scientists study plankton
Photo: NASA
Satellites equipped with color scanners measure the concentration of chlorophyll in the ocean
Red and orange indicate higher concentration of chlorophyll, while blue and green represent lower concentrations
Chlorophyll is an indicator of plankton and can be used to study plankton populations
Maine
Teacher’s Notes:
1. You may want to remind students about MODIS and SeaWiFS and their associated satellites from lesson 12 that measure ocean color here.
Photo:
NASA Earth Observatory Collection, Accessed: November 2010
Satellite image of the Gulf of Maine,
May 2002

9. Do organisms spend their entire lives as plankton?
Photo: Rolf Gradinger, NOAA/OER
Holoplankton spend their entire life cycle as plankton
Examples include dinoflagellates, diatoms and krill
Photo:
Accessed: November 2010
Diatom (Unicellular phytoplankton)

10. Do organisms spend their entire lives as plankton?
Meroplankton spend only a part of their life cycle drifting
As they mature they become nekton (free swimmers) or benthic (crawlers)
Examples include fish and crab larvae
Photo:
NOAA Photo Library
Image ID: expl0172, Voyage To Inner Space - Exploring the Seas With NOAA Collect Location: Southeast of Charleston, South Carolina Photo Date: 2003 August 7 Photographer: Jerry Mclelland Credit: Charleston Bump Expedition NOAA Office of Ocean Exploration; Dr. George Sedberry, South Carolina DNR, Principal Investigator Accessed: November 2010
Photo: NOAA
Crab larva
(zooplankton)
Phylum: Athropoda
Sub-phylum: Crustacea
Class: Malacostraca
Order: Decapoda (Five pairs of legs)

11. How are phytoplankton different from zooplankton?
Producers
Single cells or chains of cells
including the smallest plankton – picoplankton ( microns)
Remain near the surface
Zooplankton
Consumers (including herbivores and carnivores)
Include microscopic and macroscopic organisms
May vertically migrate (to a depth of 200m) during the day for protection but resurface at night to feed

12. How do scientists identify plankton?
Scientists collect samples and carefully observe their characteristics
They communicate these observations with sketches and photographs
Today, you’re the scientist!

13. Activity: Identifying Plankton
You will see ten slides depicting specimens you found during a NOAA expedition.
Note: They are from different tows representing different oceans and different depths.
Each slide will be visible for 2 minutes.
As the slides are shown, observe and, using a pencil, sketch each sample on your worksheet. If there is more than one specimen on the slide, choose one to draw. Note body shape, projections, sensory organs, appendages, type of covering and degree of transparency.

14. Activity: Identifying plankton
For each sample, write your hypothesis about the following two questions:
Is the organism phytoplankton or zooplankton?
Is it holoplankton or meroplankton?
Following the drawing section, use your sketches and resources to identify the specimens. You may work in teams
of 2-3 for this part.

15. Plankton Observation Worksheet
Specimen # ___________
Characteristics: Description
Body shape/Tail/flagella/appendages/eyes
Transparency/gills/other features
______________________
Circle one from each category:
Phytoplankton or Zooplankton
Holoplankton or Meroplankton
sketch

16. Examples of Plankton Specimen #1

17. Specimen #2

18. Specimen #3

19. Specimen #4

20. Specimen #5

21. Specimen #6

22. Specimen # 7

23. Specimen #8

24. Specimen #9

25. Specimen #10

26. End of Drawing Section
Now use your drawings to identify your specimens. Use any resources you have available or view the rest of the slides to discuss the specific organisms used.

27. Plankton Identified Specimen #1 Mixed Diatoms
Phytoplankton common in nutrient rich temperate, polar, coast and open ocean
Important oxygen producer
Occur as a single cell or in chains
Covered in shells made of silica
Beautiful marine diatoms as seen through a microscope.
Image ID: corp2365, NOAA At The Ends of the Earth Collection Photographer: Dr. Neil Sullivan, University of Southern Calif.

28. Specimen #2 Copepod Simple crustacean with jointed exoskeleton
Use enlarged first antenna to swim
Among the most common animals on Earth (most abundant of the net zooplankton)
Zooplankton. Copepod. Image ID: fish3229, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC

29. Specimen #3 – Copepod with Eggs
Bristly appendages act as paddles and create water currents that draw individual phytoplankton cells close to feed on
Many feed on zooplankton using claw like appendages to grab prey
Eggs are attached to the tail
Zooplankton. Copepod with eggs. Image ID: fish3261, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC

30. Specimen #4 – Fish Larvae
Coastal waters are rich in meroplankton
(temporary members of the plankton)
Nearly all marine fish have planktonic larvae
Fish larvae may change from herbivores to carnivores as they grow
Zooplankton. Fish larvae. Image ID: fish3363, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC

31. Specimen #5 Copepods
Although usually found near the surface plankton may also be collected at all depths even over hydrothermal vents in the deep sea
Pacific Ring of Fire Expedition. Some common zooplankton (mostly copepods) collected near the surface over East Diamante volcano. Image ID: expl0102, Voyage To Inner Space - Exploring the Seas With NOAA Collect Location: Mariana Arc region, Western Pacific Ocean Photo Date: 2004 April Credit: Pacific Ring of Fire 2004 Expedition. NOAA Office of Ocean Exploration; Dr. Bob Embley, NOAA PMEL, Chief Scientist

32. Specimen #6 Crab Larva
Some invertebrates have a whole series of different larval stages
Charleston Bump Expedition. Zooplankton. Crab larva. Image ID: expl0215, Voyage To Inner Space - Exploring the Seas With NOAA Collect Location: Southeast of Charleston, South Carolina Photo Date: 2003 August 10 Photographer: Jerry Mclelland Credit: Charleston Bump Expedition NOAA Office of Ocean Exploration; Dr. George Sedberry, South Carolina DNR, Principal Investigator

33. Specimen # 7 Dinoflagellates
Unicellular, phytoplankton
Most have a cell wall (theca) with plates of cellulose with spines and pores
May form blooms that color the water “Red Tides” or Harmful Algal Blooms (HABs)
Produce bioluminescence (light)
Some dinoflagellates live in symbiotic relationships with corals, giant clams, sea anemones.
Source: NOAA

34. Specimen #8 Krill
Not as abundant as copepods they aggregate into huge, dense schools
Prefer colder polar waters
Feed on diatoms and solid wastes of other zooplankton
Important food for whales
Tread water to stay afloat
Krill Image ID: sanc0126, NOAA's Sanctuaries Collection Location: Gulf of the Farallones National Marine Sanctuary Photographer: Jamie Hall

35. Specimen #9 Moon Jelly Gelatinous zooplankton
Common in temperate and tropical waters
Stinging cells are not toxic and don’t sting like other jellyfish
95% water but serve as food for many animals including turtles
Feed by producing a sticky mucus that traps other plankton
Reproduce sexually and asexually
Image ID: reef2547, NOAA's Coral Kingdom Collection Photographer: Florida Keys National Marine Sanctuary Staff Credit: Florida Keys National Marine Sanctuary (moon jelly)

36. Specimen #10 Octopus Larva
Temporary members of the plankton, octopus and squid become nektonic (free swimming) and benthic (crawling)
Giant squid are the largest invertebrates in the ocean
Zooplankton. Octopus larva. Image ID: fish3612, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC