Plankton does not only include phytoplankton (plants) and zooplankton (animals) but other free-floating organisms as well
This includes sea jellies (jelly fish), hatchling sea turtles, and the larval stage of many marine organisms
Many marine organisms that start out their life as planktonic (i.e. crabs, shrimp, oysters, etc.) and then are able to swim or settle to the bottom are called meroplankton
Holoplankton spends its whole life as a planktonic organism (i.e. phytoplankton and zooplankton)
Phytoplankton are independent cells where as seaweed is an aggregation of cells. Sargassum seaweed which creates huge mats in the middle of the Atlantic Ocean (in the middle of the N. Atlantic Gyre) is the only multicellular plankton.
Diatoms tend to be yellow-brown in pigment and dinoflagellates are red to green in color.
Both of these are phytoplankton but dinoflagellates do not require as much light as diatoms and they have appendages that give them limited movement.
Dinoflagellates are both beautiful and dangerous
They can bioluminescence (glow) at nighttime but there are species of dinoflagellates that are blamed for the red tide which causes paralytic shellfish poisoning (PSP).
While diatoms are seen as the main primary producers in the ocean, dinoflagellates are the link between primary producers and herbivores (i.e. zooplankton).
Herbivores include crustaceans, copepods and euphausiids
They represent 60% of all the zooplankton and an important food source for krill which baleen whales and penguin eat
Copepods are the main link between the herbivores and the first level of carnivores
Zooplankton cluster in eddies and up-welling zones where the nutrients and thus phytoplankton are found. Zooplankton migrate to the surface at night and migrate deeper (30-1500 ft) during the day. Whales and other filter feeders follow this migration pattern
Plankton Bloom at Galapagos Islands, Equador Source: http://www.nasa.gov/vision/earth/environment/ocean_plants_21.html
Hatchling sea turtles start out their life as a planktonic organism at the mercy of the currents
Hatchlings (just a few inches long) leave the Southeast coast of the United States and go into a swimming frenzy until they reach the Gulf Current
The Gulf Current or Stream goes at an impressive 3 ft/s or 3 knots.
The hatchling turtles drift in this current and end up in an eddy or in the Sargassum Sea in the middle of the Atlantic Ocean where they are protected by the seaweed from larger predators.
There are eight different species of sea turtles: 1) leatherback, 2) green, 3) black, 4) Australian flat-back, 5) loggerhead, 6) hawksbill, 7) Kemps and 8) olive ridley
Their diets vary from green turtles being herbivores to leatherbacks who specialize on seajellies
Some are omnivorous like the loggerhead and eat a variety of foods.
The Kemps Ridley is the most endangered due to the fact that it only nests on one beach in the world
The hawksbill is the second most endangered due to the beautiful “tortoise shell” that is made into jewelry
All sea turtle species are protected under the Endangered Species Act (ESA) but some have threatened status and some have endangered status. The U.S. Fish and Wildlife regulates endangered species on land and National Marine Fisheries under NOAA regulates endangered species in the oceans http://www.fws.gov/endangered/ http://www.nmfs.noaa.gov/pr/species/
Most populations are affected by habitat destruction and illegal trade. Photo of turtles caught on longlines and trawling.
Incidental catch is also a significant problem for turtles nesting on beaches where shrimp trawling is occurring
Exhausted females get caught in the nets after laying over 100 eggs and drown
United States trawlers are required to use a Turtle Excluder Devise (TED) to exclude sea turtle in their catch. Unfortunately most of the shrimp we eat in restaurants today are either imported (where TEDS are not enforced) or farm-raised
Dead Turtle caught in trawl net
TED or Turtle Excluder Devise being used
Sea Turtle Videos
There are other marine reptiles such as the Galapagos iguana, sea snakes and crocodiles
Over Fishing the Seas
Over fishing and incidental catch is driving the world’s fish stocks to historically low numbers. Even so, we harvest over 92 million metric tons of fish from the oceans world wide per year
Improved fishing gear and efforts by more nations has improved the catch of most species
Unfortunately, more than 70% of the world’s fish stocks are over fished or depleted
For more information on fish issues in the Northwest go to http://www.nmfs.noaa.gov/ and click on fish facts
For information on what you are eating!
Because bluefin tuna can sell for $90 per pound on the world market it causes the fishermen to fish down in size.
Now many companies catch juvenile bluefin and raise them in pens for the market.
Go to http://www.pbs.org/emptyoceans/eoen/tuna/index.html
for more information on bluefin, incidental catch and videos.
Sharks that have low reproductive rates are declining due to the practice of “finning”.
Asian markets demand shark fins for shark fin soup. In this practice, the fin is taken off and the shark is left to die http://www.sharktrust.org/content.asp?did=26881
While not many people have sympathy for sharks, they are an important part of the ecosystem