• What are the phytoplankton? • How do the main groups differ?
Phytoplankton Zooplankton
Nutrients Plankton “wandering” or “drifting”
(incapable of sustained, directed horizontal movement) www.shellbackdon.com
Nekton
Active swimmers Components of the Plankton
Virioplankton: Viruses
Bacterioplankton: Bacteria — free living planktobacteria; epibacteria attached to larger particles
Mycoplankton: Fungi
Phytoplankton: Photosynthetic microalgae, cyanobacteria, and prochlorophytes
Zooplankton: Heterotrophic — Protozooplankton (unicellular) and Metazooplankton (larval and adult crustaceans, larval fish, coelenterates…) Components of the Plankton
Ichthyoplankton: Planktonic fish (generally, eggs and larval stages)
Meroplankton: Planktonic organisms that have a sedentary stage. For example, phytoplankton with resting stages in sediments
Holoplankton: Wholly planktonic Components of the Phytoplankton: Older scheme
Netplankton: Plankton that is retained on a net or screen, usually Inspecting a small plankton 20 - 100 µm net. In: "From the Surface to the Bottom of the Sea" by H. Nanoplankton: Plankton that Bouree, 1912, Fig. 49, p. 61. passes the net, but Library Call Number 525.8 B77. which is > 2 µm
Ultrananoplankton: Plankton < 2µm Components of the Plankton (older scheme)
Netplankton: Plankton that is retained on a net or screen, usually 20 - 100 µm
Nanoplankton: Plankton that passes the net, but which is > 2 µm
Ultrananoplankton: Plankton < 2µm
Microzooplankton: Zooplankton in the microplankton (i.e., < 200 µm) Length Scales to Define Plankton Groups
Sieburth, J. M., Smetacek, V. and Lenz, J. (1978). Pelagic ecosystem structure: Heterotrophic compartments of the plankton and their relationship to plankton size fractions. Limnol. Oceanogr. 23: 1256-1263. Terminology and Scales: SI Units
FRACTION PREFIX SYMBOL EXAMPLE 10-1 deci d decimeter, 10cm, length of a planktivorous fish 10-2 centi c 1 centimeter, diameter of a ctenophore 10-3 milli m 1 millimeter, length of a copepod 10-6 micro µ 1 micrometer, diameter of a very small phytoplankter or a large bacterium 10-9 nano n 1 nanogram, weight of a fairly small phytoplankter 10-12 pico p 1 picogram, chlorophyll content of one small phytoplankter 10-15 femto f 1 femtogram, amount of ATP in a phytoplankter 10-18 atto a att’s a small number! Scales: The ocean is a dilute environment!
______SOME CHARACTERISTIC SCALES (values representative of coastal waters to an order of magnitude) organism linear numerical mm3 m-3 spacing in body dimension density (ppb) lengths copepod 1 mm 5 liter-1 2600 6 cm 60 dinoflagellate 35 µm 10 ml-1 225 5 mm 150 diatom 10 µm 103 ml-1 525 1 mm 100 cyanobacterium 0.6 µm 105 ml-1 11 200 µm 350 bacterium 0.5 µm 106 ml-1 65 100 µm 200 virus 0.07 µm 107 ml-1 2 50 µm 650 Characterizing Constituents of the Water
Detritus: Matter of organic origin, but incapable of reproduction (dead)
Seston: All suspended particulate matter
Tripton: The non-living part of seston
DOM: Dissolved organic matter (passes a fine filter)
CDOM: Chromophoric (colored) DOM
Neuston: Inhabiting the surface layer
Allochthonous: Developed or originating from elsewhere
Autochthonous: Endemic: originated locally Modes of Nutrition
Autotrophic: No material of organic origin is required for growth and reproduction
Auxotrophic: Physiological requirement for one or more organic compounds, but C is obtained autotrophically
Heterotrophic: Growth depends on organic material
Mixotrophic: Autotrophic and heterotrophic nutrition
Photosynthetic mixotrophs can consume organic matter by phagotrophy (engulfing particles) and osmotrophy (uptake of dissolved organic materials) Chlorophyll pigment is often equated with phytoplankton biomass
• Phytoplankton pigments influence ocean color All phytoplankton were not made equal... • Even though phytoplankton are often considered as light absorbers, packages of pigment, or organic particles, they are biologically very diverse - Phylogenetic - Metabolic - Habitat/Niche Space Light energy is collected by All plants have photosynthetic pigments chlorophylls and carotenoids
Some groups (cyanobacteria, cryptophytes, red algae) have phycobiliproteins
Pigments are used to infer species composition
Pigmentation varies with growth conditions PHYTOPLANKTON
Procarya Eucarya
(cyanobacteria (Cryptophyceae, (i.e., Synechococcus, Prochlorococcus), Diatoms,
N2 fixers Dinoflagellates, (i.e., Trichodesmium)) Coccolithophores,
Phaeocystis,
Chattonella ) The Taxonomic Groups of Phytoplankton: An Overview
1. Bacteria (prokaryotes) 2. Algae (eukaryotes) • Eubacteria (heterotroph) • Chromophyta (possess chl a and c) • Archebacteria or Archaea (heterotroph) – Cryptophyceae • Cyanobacteria (phototroph) – Dinophyceae – "real Cyanobacteria" – Chrysophyceae • filamentous cyanobacteria, fix – Prymnesiophyceae nitrogen – Bacillariophyceae (diatoms) • coccoid cyanobacteria – Raphidophyceae – Prochlorophytes (recently made a • Chlorophyta (possess chl a and b) new division) – Chlorophyceae – Prasinophyceae – Euglenophyceae
The taxonomic composition of phytoplankton does matter... Phylogenies are under constant revision
For our purposes, the older classifications are still useful
http://tolweb.org/tree?group=Stramenopiles&contgroup=Eukaryotes Page copyright © 1995 Mitchell L. Sogin and David J. Patterson PROKARYOTES (continued): Synechococcus • Discovered in 1979 • very small (ca. 1 µm) • contains phycoerythrin • can fluoresce orange or red • counted with epifluorescence microscopy or flow cytometry
http://www.woodrow.org/teachers/esi/1999/ princeton/projects/cyanopigs/data.htm reprinted from Johnson and Sieburth 1979 PROKARYOTES (continued): Prochlorococcus • Discovered in 1988 • Very small (<1.0 µm) • Divinyl chl a • Counted by flow cytometry • Most abundant autotroph on earth
reprinted from Johnson and Sieburth 1979 PROKARYOTES (continued): Trichodesmium (Oscillatoria thiebautii) Trichodesmium • Forms aggregates bloom • Fixes nitrogen • Can migrate vertically • May transport phosphate from depth to near surface • New production transports more C www.aims.gov.au/pages/research/ trichodesmium/tricho-01.html http://www.botan.su.se/fysiologi/Cyano/Tricho.jpg EUKARYOTES — having a true nucleus Chromophyta - containing chlorophyll a and c
Coscinodiscus waelesii Phytopia CD-ROM Bigelow Laboratory EUKARYOTES (continued): Division Chromophyta Class Cryptophyceae • Motile • Contain phycobiliproteins • Can be recognized by size and fluorescence (flow cytometry)
Cryptomonas
www.unex.es/botanica/ clases.htm http://mac2031.fujimi.hosei.ac.jp/PDB/Images/Mastigophora/Cryptomonas/Cryptomonas.jpg EUKARYOTES (continued): Division Chromophyta Class Bacillariophyceae (Diatoms) • Cannot swim; Can regulate buoyancy (some can migrate) • Require silicon; Encased in Pill-box shaped silica frustule • Important in coastal areas and spring blooms
http://www1.tip.nl/~t936927/art_deco.html www.oregonbd.org/Class/Chap2.htm Diatoms
P. Roger Sweet, Indiana University
www.coastalstudies.org/stellwagen/phyto.htm Diatoms pennate
pennate
Images from http://www.microscopy-uk.org.uk/mag/wimsmall/diadr.html
Silica frustule Side View
epitheca