Marb 435 1st Edition Lecture 3 Outline of Current Lecture Introduction to information about zooplankton life cycles and preparation for zooplankton lab Current Lecture Plankton Terms to know 1 Plankton Drifting organism that inhabit the water column of seas oceans or lakes Passive transport with currents Often capable of vertical migration in the oceans water columns 2 Neuston Type of plankton that is specifically associated with the uppermost layer of the water column at the surface or just below 3 Nekton Organisms that live in the water column of seas oceans and lakes and can propel themselves independently of the water currents 4 Phytoplankton Photosynthetic protists and bacteria and archaea They are the primary producers in the ocean and are extremely ecologically important 5 Zooplankton microscopic unicellular and multicellular organisms with heterotrophic nutrition that are capable of vertical migrations in the water column 6 Holoplankton spend their entire lives in planktonic form 7 Meroplankton are planktonic for only part of their life cycles often are the larvae of many marine invertebrates 8 Planktotropic feeds on other planktonic organisms long larval phase 9 Lecithotropic feeds on yolk supplied with the egg short larval phase Zooplankton Size Classes Microzooplankton 20 to 200 p Mesozooplankton 0 2 20 mm Copepods often represent 50 90 of the catch Macrozooplankton 2 20 cm Less abundant than smaller plankton and less susceptible to capture Examples include larval fish shrimps and salps These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Pros and Cons of Larvae Dispersal Potential advantages of dispersal by larvae Reduces overcrowding Allows colonization of new habitats Promotes genetic exchange between populations Avoiding competition with adults Risks of dispersal by planktonic larvae Limited yolk reserves might not last and larva may starve High risk of predation Manta rays whale sharks and baleen whales are pelagic plankton predators Many benthic invertebrates also feed on plankton Larvae might never find suitable habitat to settle Live in viscous liquid medium in which locomotion is difficult Defenses plankton have against predation Transparence Protective Spines Chemical Defenses distasteful or toxic EXAMPLE Small amounts of didemnins from larvae or adults of the Caribbean tunicate Trididemnum solium cause vomiting in fish Diel swimming rhythms Synchronized mass spawning Abbreviated larval phases Zooplanktonic Feeding and Motion in Water Column Zooplankton are usually suspension feeders of phytoplankton bacteria and suspended organic matter They generally use cilia and mucus for food capture except for arthropods which use setae May be passive filter feeders or may actively pursue particle Zooplankton can move through use of cilia jointed appendages or whole body contractions Most zooplankton can actively control their vertical position in the water column by using directed swimming and also slight changes in buoyancy Many species aggregate in deeper waters during the day and rise at night for feeding and some leave the bottom for mating e g swarming polychaetes Things you also need to know Alastair Hardydesigned the first Continuous Plankton Recorder CPR in the 1920s which was a device that was towed behind boats to capture plankton continuously CO2 forms bicarbonate HCO3 and carbonate CO32 in seawater and that lowers the pH Increase in atmospheric CO2 from pre industrial 280 atm to 370 atm has decreased surface ocean pH by 0 12 units to current 8 2 The possible effects of this change on planktonic life are hard to predict