Understanding Meroplankton: Holoplankton vs. Meroplankton in the Ocean Ecosystem

1. MEROPLANKTON Part I

2. Plankton • Holoplankton Portuguese Man-O-War

3. Plankton • Meroplankton

4. Holoplankton or Meroplankton?

5. Do note that it is not always easy to place an organism in one exclusive group. There may be some exceptions.

6. Comb jelly squid White spotted Sea cucumber Bacteria octopus Dinoflagellate Giant clam Gannet Triggerfish Whale shark lobe coral Copepods

7. Krill Mola mola (ocean sunfish) tunicate Peacock flounder Manta ray longnose hawkfish collector urchin Upside down Jellyfish Manta ray Spanish Dancer Nudibranch Spinner dolphin Seven eleven crab Seahorse

8. needlefish Sting ray Snowflake moray Garden eel spotted boxfish Orange Spine Unicornfish Commerson’s frogfish Divided flatworm

9. Organisms Bacteria holoplankton Tiny organisms can’t fight the current. Many do live inside other animals. For instance, many chemosynthetic bacteria from the hydrothermal vents live inside tube worms. Dinoflagellate holoplankton These have flagella for moving in the water, but they are very small and can’t fight the current. Some dinoflagellates, like zooxanthellae, live inside the tissue of coral, anemones, jellyfish, and giant clams. Copepod holoplankton Tiny organisms can’t fight the current, but they are able to move during their daily vertical migration in the water column. Krill Holoplankton/ Meroplankton (pelagic) The small ones are holoplankton, but some get large enough that they become good planktonic swimmers. Upside-down Jellyfish Meroplankton Jellyfish have 2 stages in their lifecycle: medusa and polyp. During the polyp stage they are attached to the bottom; however, during the medusa stage they are free swimming, but can’t fight a current. Also this particular species lives on the bottom but can swim vertically. Answer Explanation

10. Seahorse Holoplankton (benthic) If its tail wasn’t wrapped around seagrass, it would probably be swept away by a current. It does live at or near the bottom. Snowflake moray Meroplankton (benthic) Lives in crevices and is a good swimmer as an adult. Commerson’s frogfish Meroplankton (benthic) Not a strong swimmer, but meroplankton is a good guess. Comb jelly Holoplankton These animals have eight rows of cilia that don’t really do much for helping them swim. Giant clam Meroplankton (benthic) After hatching from an egg, their larval stage settles to the bottom and they become bottom dwellers. Lobe coral Meroplankton (benthic) Corals produce a drifting planula larva that will settle to the bottom forming a polyp. Many will form a calcium carbonate skeleton.

11. Tunicate Holoplankton/ Meroplankton (benthic) All tunicates have a tadpole larval stage. Most will settle to the bottom and be benthic dwellers; however, there are pelagic tunicates that remain as plankton Collector urchin Meroplankton (benthic) Larvae settles to the bottom and that’s where the urchin remains grazing on algae. Seven eleven crab Meroplankton (benthic) Larvae settles to the bottom; there are some pelagic crabs that are good swimmers Sting ray Nekton (benthic) Lives near the bottom and is ovoviparous, gives birth to 5-13 live offspring. Spotted boxfish Meroplankton (demersal) It does swim in the water column. Don’t eat it.

12. squid Meroplankton (pelagic) These are strong swimmers as adults octopus Meroplankton (benthic and pelagic) Most are benthic, but there are a few pelagic varieties Triggerfish Meroplankton (demersal) It does swim in the water column. Mola mola (ocean sunfish) Holoplankton/ Meroplankton (pelagic) Tough call! Some scientists call it plankton because they are poor swimmers; others agree that they can swim some. They follow the currents for their plantivorous diet

13. Manta ray Nekton (pelagic) Swims in currents searching for plankton. Ovoviviparous, gives birth to 1-2 pups Spinner dolphin Nekton Viviparous, gives birth live to 1 offspring Needlefish Meroplankton (demersal) Best guess is demersal, but likes to hang out at the surface. Divided flatworm Meroplankton (benthic) It eats tunicates and mollusks around reefs. Sea cucumber Meroplankton (benthic) It sucks sand like a vacuum cleaning the detritus; it’s a deposit feeder.

14. Gannet (bird) Nekton Strong swimmer searching for fish. Whale shark Nekton For the largest fish in the sea, it is ovoviviparous, and up to 300 young have been counted in one female

15. MEROPLANKTON Part II

16. Guess whom the following grew up to be: A. B. C. D.

17. Phylum Chordata A. dolphin B. fish C. cat D. human

18. Match the following animals to their larval form.

19. 1. 2. 3. 4. Larvae 5. 6. 7. 8. 9. 10. 11. 12.

20. 13. 14. 15. 16. Larvae 18. 19. 20. 21. 22.

21. Adult marine fire worm pom pom crab Seahorse squid Sponge cowfish Giant clam blue tang octopus Triggerfish leaf scorpionfish lobe coral

22. Adult Mola mola (ocean sunfish) crown of thorns starfish tunicate Peacock flounder Seven eleven crab brittle star Snowflake moray slipper lobster Spanish dancer (nudibranch) Divided flatworm

23. Answers 1. Porifera (parenchymella larvae) sponge 2. Cnideria (planula larvae) lobe coral 3. Flatworm (Müllers larvae) divided flat worm 4. Mollusca and Polychaeta (trochophore larvae-after hatching) giant clam 5. Mollusca (veliger larvae-later stage) Spanish dancer (nudibranch)

24. 6. Mollusca- Squid squid Answers 7. Mollusca- octopus octopus 8. polychaete marine fire worm 9. crab (zoea; early crab stage) seven eleven crab 10. Crab (megalopa; final planktonic stage) pom pom crab

25. 11. lobster (phyllosoma) slipper lobster Answers 12.Starfish (bipinnaria larvae) crown of thorns starfish 13. Brittle star (Ophiopluteus larva) brittle star 14. tunicate tunicate 15. seahorse seahorse

26. 16. triggerfish triggerfish Answers 17. Eel (leptocephalus) snowflake moray 18. cowfish cowfish 19. Leaf scorpion fish leaf scorpionfish 20. Blue tang blue tang

27. 21. flounder peacock flounder Answers 22. Ocean sunfish ocean sunfish