OCN 201 Biology Lecture 4http://video.conncoll.edu/f/pasiv/lucid/Cyanophora-900.html

Marine Primary Producers

Photo: C. Schvarcz (Steward Lab, UH Manoa)

Macroalage & Phytoplankton

Primary production

• The production of organic compounds from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis (or chemosynthesis)

• Carried out by autotrophs

• On land primary producers are mostly macroscopic

• In the sea nearly all primary production is due to microscopic phytoplankton

Terrestrial Primary Producers

Macroalgae & SeagrassesLarge Marine Primary Producers

Kelp Forest Locations

Exception: Sargassum, a planktonic macroalga

Macroalgae mostly limited to coastal areas

BUT: most life in the sea is microscopic including the primary producers and consumers

Flagellates & Coccolithophores

Diatoms & Dinoflagellates

Cyanobacteria & Picoeukaryotes

MARINE PHYTOPLANKTON

Thousands

Millions

Hundreds of Millions

How Many in a Liter? How much Production?

0

10

20

30

40

50

60

70

80

90

100

0.2 to 2 µm

2 to 10 µm

>10 µm

Perc

ent o

f Prim

ary

Prod

uctio

n

North Pacific

Together, these tiny phytoplankton produce half the oxygen on the planet!

• Prochlorococcus

• Synechococcus

Prokaryotic Phytoplankton (Cyanobacteria)

Responsible for a lot of the primary productivity in the open ocean

(and others)

Eukaryotic Phytoplankton have Plastids that originated as symbiotic cyanobacteria

plastids

Cyanophora

Image: https://ncma.bigelow.org/tree-of-life/archaeplastida/glaucophyta

This process is called kleptoplasty

Some Eukaryotes Steal Plastids from Others

• Picoeukaryotes

• Diatoms

• Dinoflagellates

• Coccolithophores

Eukaryotic Phytoplankton

PicoeukaryotesOstreococcus - smallest free-living eukaryote

François

Universi Wenche Eikrem and

By eye

Light Microscope

ElectronMicroscope

PicoeukaryotesMicromonas pusilla

Dinoflagellates

Diatom Coccolithophore

picoeukaryote

cyanobacteriumSilica frustule Calcium carbonate plates

Cellulosethecal plates

NaviculaFragilaria

DIATOMS

Chaetocerous

http://bioloc.oce.orst.edu/SherrLab/BESTMG9%20epi%20Chaeto.jpg

Siliceous Sediments

http://www.marinebio.net/marinescience/02ocean/mgbottom.htm

http://www.bhikku.net/archives/03/img/diatoms.JPG

Dinoflagellates

Emiliania huxleyi

http://images.quickblogcast.com/77583-67933/coccobloom.JPGhttp://media-2.web.britannica.com/eb-media/94/74594-004-02A9BBFF.jpg

Summary• Kelp and sea grasses important in nearshore in

nutrient rich areas BUT most primary producers are microscopic

• Photosynthetic bacteria (cyanobacteria) are most abundant primary producers on the planet

• The larger photosynthetic planktonic eukaryotes are also very abundant

• Some important groups: diatoms & coccolithophores have hard shells that create massive (and inspirational) mineral deposits