Marine Primary Producers

Photo: C. Schvarcz (Steward Lab, UH Manoa) OCN 201 Biology Lecture 4 http://video.conncoll.edu/f/pasiv/lucid/Cyanophora-900.html 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

Large Marine Primary Producers Macroalgae & Seagrasses Kelp Forest Locations Macroalgae mostly limited to coastal areas

Exception: Sargassum, a planktonic macroalga BUT: most life in the sea is microscopic including the primary producers and consumers MARINE PHYTOPLANKTON

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

How Many in a Liter? How much Production? Diatoms & Dinoﬂagellates Thousands

100 >10 µm 90 2 to 10 µm 80

70 0.2 to 2 µm

60 Flagellates & Coccolithophores Millions 50

Percent of Primary Production Percent 10

North Paciﬁc Hundreds of Millions

Cyanobacteria & Picoeukaryotes Prokaryotic Phytoplankton (Cyanobacteria)

• Prochlorococcus • Synechococcus (and others)

Responsible for a lot of the primary productivity in the open ocean Eukaryotic Phytoplankton have Plastids that originated as symbiotic cyanobacteria

plastids

Cyanophora

Image: https://ncma.bigelow.org/tree-of-life/archaeplastida/glaucophyta Some Eukaryotes Steal Plastids from Others This process is called kleptoplasty Eukaryotic Phytoplankton

• Picoeukaryotes • Diatoms • Dinoﬂagellates • Coccolithophores Picoeukaryotes Ostreococcus - smallest free-living eukaryote By eye François

Light Electron Microscope Microscope

Universi Wenche Eikrem and Picoeukaryotes

Micromonas pusilla Diatom Coccolithophore

Silica frustule Calcium carbonate plates cyanobacterium

Cellulose thecal plates picoeukaryote

Dinoﬂagellates DIATOMS Fragilaria Navicula

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.JPG http://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