Lesson 17 Plankton Marine Biology What exactly are

Lesson 17: Plankton Marine Biology

What exactly are plankton? 1. Plankton are weakly swimming or drifting organisms 2. “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 2

Why are plankton important? 3 l Important part of global carbon cycle l Food source (basis of the food web) l Producer of oxygen (photosynthesis)

Photosynthesis primer l Recall from biology that autotrophs (aka primary producers) like plants or algae create carbohydrates (usable energy) from light through photosynthesis: CO 2 + H 2 O C 6 H 12 O 6 (carbohydrate) + O 2(oxygen) l This energy supplies entire food webs as organisms are eaten up the food chain Sun 4 Autotrophs (primary producers) Solar energy Heterotrophs (consumers) Plant/animal energy sources (carbohydrates)

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. Photo: NOAA This map shows productivity in the Oceans 5 Red and yellow are most productive, followed by green and blue. Black is least productive.

How are plankton studied? l l Collected with special nets and sampling bottles Underwater cameras Microscopes Satellites Bongo nets may be towed over the side of the ship to collect plankton. 6 Photo: NOAA

Satellites can also help scientists study plankton Photo: NASA l 7 Satellites equipped with color scanners measure the concentration of chlorophyll in the ocean l Red and orange indicate higher concentration of chlorophyll, while blue and green represent lower concentrations l Chlorophyll is an indicator of plankton and can be used to study plankton populations Maine Satellite image of the Gulf of Maine, May 2002

Do organisms spend their entire lives as plankton? l Holoplankton spend their entire life cycle as plankton l Examples include dinoflagellates, diatoms and krill Photo: Rolf Gradinger, NOAA/OER Diatom (Unicellular phytoplankton) 8

Do organisms spend their entire lives as plankton? l l l 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 9 Crab larva (zooplankton) Phylum: Athropoda Sub-phylum: Crustacea Class: Malacostraca Order: Decapoda (Five pairs of legs)

How are phytoplankton different from zooplankton? l 10 Phytoplankton Producers l l Single cells or chains of cells including the smallest plankton – picoplankton (0. 2 -2 microns) l l Remain near the surface l Zooplankton Consumers (including herbivores and carnivores) Include microscopic and macroscopic organisms May vertically migrate (to a depth of 200 m) during the day for protection but resurface at night to feed

How do scientists identify plankton? 11 l Scientists collect samples and carefully observe their characteristics l They communicate these observations with sketches and photographs l Today, you’re the scientist!

Activity: Identifying Plankton l 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. 12 l Each slide will be visible for 2 minutes. l 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.

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. 13

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 14 sketch

Examples of Plankton Specimen #1 15

Specimen #2 16

Specimen #3 17

Specimen #4 18

Specimen #5 19

Specimen #6 20

Specimen # 7 21

Specimen #8 22

Specimen #9 23

Specimen #10 24

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. 25

Plankton Identified Specimen #1 Mixed Diatoms l l 26 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: corp 2365, NOAA At The Ends of the Earth Collection Photographer: Dr. Neil Sullivan, University of Southern Calif.

Specimen #2 Copepod l l l 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: fish 3229, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC 27

Specimen #3 – Copepod with Eggs l l l 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: fish 3261, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC 28

Specimen #4 – Fish Larvae l l l 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. 29 Image ID: fish 3363, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC

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. 30 Image ID: expl 0102, 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

Specimen #6 Crab Larva l Some invertebrates have a whole series of different larval stages l 31 Charleston Bump Expedition. Zooplankton. Crab larva. Image ID: expl 0215, 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 2003. NOAA Office of Ocean Exploration; Dr. George Sedberry, South Carolina DNR, Principal Investigator

Specimen # 7 Dinoflagellates l Unicellular, phytoplankton l Most have a cell wall (theca) with plates of cellulose with spines and pores l May form blooms that color the water “Red Tides” or Harmful Algal Blooms (HABs) Source: NOAA 32 l Produce bioluminescence (light) l Some dinoflagellates live in symbiotic relationships with corals, giant clams, sea anemones.

Specimen #8 Krill l l 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 l 33 Krill Image ID: sanc 0126, NOAA's Sanctuaries Collection Location: Gulf of the Farallones National Marine Sanctuary Photographer: Jamie Hall

Specimen #9 Moon Jelly l l l 34 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 l Image ID: reef 2547, NOAA's Coral Kingdom Collection Photographer: Florida Keys National Marine Sanctuary Staff Credit: Florida Keys National Marine Sanctuary (moon jelly)

Specimen #10 Octopus Larva l l 35 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: fish 3612, NOAA's Fisheries Collection Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC