Transcript Document

Lecture 2:
Terminology and
Introduction to Phytoplankton
Introduction to Biological Oceanography
2004
Terminology and Scales
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:
Inspecting a small plankton
net. In: "From the Surface to
the Bottom of the Sea" by H.
Bouree, 1912, Fig. 49, p. 61.
Library Call Number 525.8
B77.
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
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!
________________________________
________________________________
___________________
S OME CHARACTERIS TIC SCALES
(val ues representative of coastal waters to an order of magnitude)
organism
copepod
dinoflagellate
diatom
cyanoba cterium
bacterium
virus
linear
dimension
1 mm
35 µm
10 µm
0.6 µm
0.5 µm
0.07 µm
numerical
density
5 liter-1
10 ml-1
-1
103 ml
-1
105 ml
-1
106 ml
-1
107 ml
mm3 m-3
(ppb)
2600
225
525
11
65
2
spacing
6 cm
5 mm
1 mm
200 µm
100 µm
50 µm
in body
lengths
60
150
100
350
200
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
Characterizing Environments
Euphotic Zone: Surface layer, to the depth where positive
net photosynthesis is no longer possible (compensation
point)
Alexandrium fundyense
0.50
-1
Specific Growth Rate (d )
Often defined as the zone that extends
from the surface to the depth at which
light is reduced to 1% of its surface value
(sometimes 0.1% light level is used).
This is arbitrary and unnecessary —
the 1% light depth is much better lit at the
equator than at high latitudes in winter on
a cloudy day!
0.60
0.40
0.30
0.20
  ma xG  [tanh(
0.10
Strain ccmp1980
µmaxG = 0.5987 ± 0.0872 d-1
alpha = 0.0079 ± 0.0025 d-1 (µmol m-2 s-1)-1
Ec = 22.0 ± 5.97 µmol m-2 s-1
Ec constrained to >= 22µmol m-2 s-1
µmaxNet = 0.4296 ± 0.0872 d-1
(assuming same error as for µmaxG)
0.00
May occur at depths exceeding 100 m in
oligotrophic open-ocean waters or it may
be less than 10 m in eutrophic or turbid
waters
E
  Ec
)  tanh(
)]  (E  E c )
ma xG
ma xG
-0.10
0
100
200
300
400
Irradiance (µmol m
-2
500
-1
s )
Compensation Irradiance =
22 µmol m-2 s-1
600
Characterizing Environments
Eutrophic:
Refers to the level of nutrients
hypereutrophic > eutrophic > mesotrophic > oligotrophic
Oceanic:
Open ocean, water depth > 200 m
Neritic:
Beyond low water out to the edge of the
shelf (i.e., depth < about 200 m)
Pelagic:
Includes both oceanic and neritic
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)
Important Questions in Biological Oceanography
How much is there?
Primary Standing Crop
Instantaneous value of the amount of living
plant material present in the water
(g m-3 or g m-2)
“Material” can be expressed in terms of many substances, but organic
carbon is fairly well accepted as the preferred measure of biomass for
field applications (phytoplankton carbon can not be measured directly,
though, because of detrital component of POC [particulate organic
carbon]). Chlorophyll a is a highly variable index of phytoplankton
biomass.
Important Questions in Biological Oceanography
How fast is it being produced?
Net Primary Productivity (Production)
Net rate of synthesis of organic material from inorganic
compounds such as CO2 and water
Chemosynthesis: chemical reducing power comes from
reduced inorganic compounds such as H2S and NH3
Photosynthesis: reducing power comes from light energy
Photosynthetic primary production is usually measured and
considered to dominate.
g C m-3 h-1
g C m-2 d-1
Important Questions in Biological Oceanography
How fast is it being produced?
Secondary Production: Net rate of synthesis of organic matter resulting
from the assimilation of organic compounds supplied by primary
production
Examples:
Herbivores eat phytoplankton; their growth is secondary production
Heterotrophic bacteria assimilate compounds released from
phytoplankton; this is also secondary production
Tertiary production: follows the same line of reasoning.
Existence of detritovores, omnivores, mixotrophs makes for
complicated relationships
Phytoplankton - autotrophic
P. Roger Sweet, Indiana University
Diatoms
www.whoi.edu/redtide/rtphotos/
Dinoflagellates

~8h 

CO 2  2H 2 O 
(CH 2O) +H 2O +O2
Photosynthesis
Why is phytoplankton
ecology important?
Phytoplankton provide the basis for most marine food webs
Ecosystem
Net Primary
Total Biomass
Turnover
Productivity
(1015 grams) Time (years)
(1015 grams/year)
Marine
35-50
1-2
0.02-0.06
Terrestrial
50-70
600-1000
9-20
Harmful Algal
Blooms
Fish Kills
From GEOHAB Science Plan
and http://europa.eu.int/comm/research/rtdinfsup/en/world4.htm
Shellfish Toxicity
European Commission - Ocean Research - The
balance of living organisms
Noxious foams or scums
Diatom
Brown algae
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
photosynthetic pigments
All plants have
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
(i.e., Synechococcus,
Prochlorococcus),
(Cryptophyceae,
N2 fixers
(i.e., Trichodesmium))
Dinoflagellates,
Diatoms,
Coccolithophores,
Phaeocystis,
Chattonella )
The Taxonomic Groups of Phytoplankton:
An Overview
1. Bacteria (prokaryotes)
•
•
•
Eubacteria (heterotroph)
Archebacteria or Archaea (heterotroph)
Cyanobacteria (phototroph)
– "real Cyanobacteria"
• filamentous cyanobacteria, fix
nitrogen
• coccoid cyanobacteria
– Prochlorophytes (recently made a
new division)
2. Algae (eukaryotes)
• Chromophyta (possess chl a and c)
– Cryptophyceae
– Dinophyceae
– Chrysophyceae
– Prymnesiophyceae
– Bacillariophyceae (diatoms)
– Raphidophyceae
• Chlorophyta (possess chl a and b)
– 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
OLDER SCHEMES SERVE A PURPOSE
Jeffrey and Vesk UNESCO volume
PROKARYOTES
without a true nucleus
Cyanobacteria:
– Also called blue-green algae
– Major accessory pigments: phycoerythrin, zeaxanthin
- Synechococcus
- Prochlorococcus
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)
•
•
•
•
Forms aggregates
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
Trichodesmium
bloom