180 likes | 243 Views
Marine Biology. Plankton Communities. What is plankton?. Planktonic organisms have limited powers of locomotion Planktonic animals are not necessarily small or microscopic Portuguese Man-o-War. Plankton Nets and Meshes. MOCNESS. Nets used include: bongo, neuston, and MOCNESS. Veliger.
E N D
Marine Biology Plankton Communities Plankton Communities
What is plankton? • Planktonic organisms have limited powers of locomotion • Planktonic animals are not necessarily small or microscopic • Portuguese Man-o-War Plankton Communities
Plankton Nets and Meshes MOCNESS • Nets used include: bongo, neuston, and MOCNESS Plankton Communities
Veliger Echinoderm Ctenophore Trochophore Arrow worm Plankton Diversity • Holoplankton - spend their entire life in the plankton • Meroplankton - spend only part of their life in the plankton Plankton Communities
Phytoplankton • Phytoplankton is the base for all life in the sea • Usually, microscopic organisms which are capable of photosynthesis (autotrophs) • Photosynthesis - the formation of energy rich compounds from inorganic materials Sunlight + H20 + CO2 C6H12O6 (Glucose) + O2 • Primary Production • Types of producers: benthic microalgae, macroalgae, & phytoplankton For phytoplankton to survive they must stay in the upper part of the water column Plankton Communities
Phytoplankton Diversity • Diatoms • Unicellular and can form large colonial groups • Test is made of silicon dioxide (SIO2) • Frequently spined and ornamental, oil droplets keeps it afloat Colonial Diatom Diatom Plankton Communities
Diatom Reproduction Plankton Communities
Phytoplankton Diversity • Dinoflagellates • Possess two unequal flagella (usually solitary) • Have external skeleton of carbohydrate plates • Many species have chlorophyll but can also ingest food Noctiluca Plankton Communities
Toxic Dinoflagellates • Some species release large amounts of highly toxic neurotoxins • Ptychodiscus causes red tides • Zooxanthellae are photosynthetic dinoflagellates that have symbiotic relationships in animal hosts • They fix carbon dioxide, release oxygen and provide nutrients • Pfiesteria is a dinoflagellate that spends most of its life as a cyst in the sediment Red Tide Plankton Communities
Zooplankton • Holoplankton • Important grazers that provide a link between primary producers and smaller predators • Foraminifera • Single-celled, calcium carbonate (CACO3) skeletons • Most individuals live on or in the bottom Plankton Communities
Holozooplankton • Radiolaria • Single celled, silicon dioxide skeletons • Mostly planktonic with ornate spines used for flotation Plankton Communities
Copepods Holozooplankton • Copepods • The primary herbivores in the sea • Small, several mm. in length and weak swimmers Plankton Communities
Zoea Larvae Megalop Larvae Meroplankton and Plankton Distribution • Contain virtually all phyla from many marine habitats • Many species go through several life stages Plankton Communities
Adaptations of plankton • The biggest challenge for plankton is to stay afloat in the water column • Phytoplankton may sink below the light; zooplankton may sink below the food • By increasing the surface area = decrease the sinking rate Plankton Communities
Adaptations of plankton • Reduction of weight • Alter body composition to fluids which are less dense • Oils and fats • Use special gas filled floats • Man-o-War Plankton Communities
Larvae and Larval Ecology • A large number of marine organisms produce larvae as part of their life cycle • Larvae are independent morphological stages that arise from fertilized eggs • Must undergo profound changes before becoming an adult (metamorphosis) • Most organisms comprising benthic communities have a free-swimming larval stage • What are the possible benefits for having a free-swimming larval stage? Plankton Communities
Different Larval Types • Planktotrophic larvae Barnacle larvae Plankton Communities
Different Larval Types • Lecithotrophic larvae Yolk-sac larvae Plankton Communities