Algal Culture – unicellular and
multicellular (seaweeds)
Total Plant Aquaculture = 15,781,000 mt
• Unicellular or micro-algal production - ?
• Multicellular – seaweeds = 13,241,000 mt
84% of total plant aquaculture
Culture conditions necessary for growth
of algae and seaweeds
A. Light
B. Carbon dioxide
C. Appropriate temperature
D. Nutrients
E. Salinity
F. Mixing
Photosynthesis
LIGHT ENERGY
Carbon dioxide + water {CHLOROPHYLL} Oxygen + Sugar
12 (CO2 + H2O) {CHLOROPHYLL} O2 + C6H12O6
Phytoplankton (micro-algae) are microscopically small
single-celled plants free floating in the water. Diatoms are
a special group of algae with cell walls made of silicate.
Some species use flagella or cilia to move within the water.
Isochrysis = 5 microns in diameter
Chaetoceros = 6 microns in diameter
Note: the diameter of a human hair = 40 – 120 microns
Diatoms
*Skeletonema costatum
*Chaetoceros calcitrans
Size μ
Flagellates
6 Chlamydomonas
coccoides
2.5 Nannochloris occulata
Size μ
7
2
*Chaetoceros gracilis
6 Dunaliella tertiolecta
6.5
Phaeodactylum
tricornutum
*Thalassiosira
pseudonana (3H)
5 *Tetraselmin suecica
8.5
5.5 *Isochrysis galbana,
(T.ISO)
5
*Monchrysis lutheri
4
Table 1. Algal species commonly used as food in
aquaculture. Those marked with an asterisk are most
often fed to oysters and clams.
Provasoli-Guillard National Center for
Culture of Marine Phytoplankton
Quan.
CCMP's L/20 Medium
Sterilize 1.0 L filtered
seawater in teflon bottle.
After the seawater has
cooled, aseptically add the
following stock solutions.
Compound
Stock Sol.
0.1 mL
NaNO3
75.0 g/L
dH2O
0.1 mL
NaH2PO4*H2O
5.0 g/L
dH2O
0.1 mL
NH4Cl
26.8 g/L
dH2O
0.1 mL
Na2EDTA*2H2O
37.2 g/L
dH2O
5.0 mL
Alkaline Soil
Extract
(see recipe)
0.1 mL
f/2 Trace Metal
Solution
(see recipe)
0.05 mL
f/2 Vitamin
Solution
(see recipe)
Adjust pH to 7.8-8.2 with HCl
f/2 Trace Metal Sol.
Alkaline Soil Extract
In a flask add two
parts by volume
distilled water (dH2O)
to one part rich
organic garden soil
(containing no recent
applications of
chemical fertilizer or
pesticides). Add 2-3 g
NaOH/liter. Autoclave
for 2 hours, and filter
when cool. This
concentrated extract is
diluted 1:50 in dH2O
for the final working
stock. (Seawater may
substituted for dH2O if
the extract is to be
used for marine
species).
To 950 ml distilled H2O add:
Quan.
Compound
Stock Sol.
3.15 g
FeCl3*6H2O
-
4.36 g
Na2EDTA*2H2O
-
1.0 mL
CuSO4*5H2O
9.8 g/L dH2O
1.0 mL
Na2MoO4*2H2O
6.3 g/L dH2O
1.0 mL
ZnSO4*7H2O
22.0 g/L dH2O
1.0 mL
CoCl2*6H2O
10.0 g/L dH2O
1.0 mL
MnCl2*4 H2O
180.0 g/L
dH2O
Final volume to 1.0L with dH2O. Autoclave
f/2 Vitamin Solution
To 950 mL dH2O add:
Quan.
Compound
Stock
Sol.
1.0 ml
Vitamin B12
1.0 g/L
dH2O
10.0 ml
Biotin
0.1 g/L
dH2O
200.0 mg Thiamine HCl
-
Make final volume up to 1.0 L with
dH2O. Filter sterilize & refrigerate.
Note: Vitamin B12 and Biotin are
obtained in a crystalline form. To
prepare the Vitamin B12 Stock
Solution, for each 1.0 mg of Vitamin
B12 add 0.89 mL dH2O). To prepare
the Biotin Stock Solution, for each
1.0 mg of Biotin add 9.6 mL dH2O
Micro-algal culture
Algal
growth
curve
Blue-green algae – Spirulina
70 million dollar California industry
Earthrise is the world's largest Spirulina farm, covering a 108
acre site. Earthrise produces over 500 metric tons of dry
powder annually and sells in over 40 countries.
ANS - 18; Algal culture

The 30 Spirulina ponds have food grade liners.
Each is 5000 square meters, over an acre in size
and larger than a football field.
Clean fresh water and nutrients are added daily to
feed the algae, mixed by 50-foot paddlewheels in
each pond.
Culture conditions, such as alkalinity are optimized
for Spirulina growth.
ANS - 18; Algal culture
Macroalgae – (multicellular)
Red seaweeds such as nori or Porphyra
Brown seaweeds or “kelps”; high in algin
Red & brown seaweeds dwell almost exclusively in marine (or
coastal) environments. The group dominates many benthic
marine biotas, sometimes reaching from the ocean floor to its
surface. In general, they are not free-floating organisms, but
are attached to rock, coral, or other firm surfaces.
The group is found primarily in colder waters of the northern
hemisphere, with the largest forms occurring in cooler
waters, rather than in the tropics. Many familiar species, such
as rockweed, are intertidal, and are exposed to the air at
low tide.
1There are a few pelagic (= floating) seaweeds, the best known example is
Sargassum which is prominent in the Sargasso Sea
Red seaweeds – Nori (Porphyra)
high in agar and carrageenan
While only 562,000 tonnes
were produced in 2008
the value was $ 940
million making nori the
most valuable of the
cultured seaweeds
The name come from the
strong red color of the
young thallus stage,
however as it grows the
thallus becomes a dark
purple.
↑ protein - 25 - 35% of dry weight
75% of protein & carbohydrates
digestible
↑ vitamins and minerals (vitamin C
content 1.5 X that of oranges and it
is a good source of iodine)
Nori – coldwater sp. – 10 – 18oC
Since the 17th century
Japanese fishermen
planted "hibi"
1949, the filamentous
Conchocelis-phase of
Porphyra was discribed
by the British
phycologist, Kathern
M. Drew-Baker
Nori production cycle
optimum growth 10 – 18oC
British
phycologist,
Kathern M.
Drew-Baker
in 1949,
found the
filamentous
Conchocelisphase in the
life history of
Porphyra
Cultivation of the conchocelis stage
Page 2
• May to September

 Sporophytes are seeded on
mollusk shells (May) in long
concrete tanks with 20 – 30 cm
of fertilized seawater in depth.
 Optimum growth of the
conchocelis phase is 20 – 25 oC
September to October
 The sporophytes release
conchospores, which are
seeded on special cultivation
nets that have been placed in
the tanks.
 Water in the tank agitated to
obtain an even distribution of
the conchospores
 Cultivation of the thallus stage
 The seeded nets are fixed to rafts for growout
 As the thallus grows, it will be cut near the holdfast
allowing further growth, allowing a harvest every couple
of weeks.
 Processing of Porphyra
 The harvested thalli are wasted in seawater to remove
contaminants
 Chopped into small pieces and washed again briefly
 The thallus suspension is poured into a metallic
framework with a plastic net at the bottom to produce
individual sheets when dryed.
 These sheets are then packaged and sold.
Brown seaweeds or “kelps”
 Laminaria (Japanese kelp) eaten
as a vegetable & grown as a
commercial source of alginates)
– Production = 4.8 million tons
in 2008 with a value of $ 2.8
billion
 Unidaria (wakame) also eaten
as a vegetable particularly in
soups - Production = 1.8 million
tons in 2008
Both Laminaria and Undaria are cold-water species and
thus are winter crops. Laminaria < 16oC and for Undaria ~
12 oC is optimum
ANS - 18; Algal culture
Macrocystis (giant bladder kelp)
An important brown algal species along the California coast is: ♦
 Found along the Pacific coast of North America from central California
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to Baja California.
This species may grow to lengths of 60 m (200 ft) with its upper
fronds forming a dense canopy at the surface.
Kelp begins life as a microscopic spore, which grows into a tiny male
or female plant called a gametophyte. These plants produce eggs and
sperm, which fertilize and grow to form the large plants (sporophytes)
The large sporophytes then release many new spores to start the
process over again. The minimum amount of time needed to complete
the Macrocystis life cycle is believed to be 12 to 14 months although
in the environment, grazing by animals and shading by other plants
affect this rate of development.
Giant kelp prefers depths less than 40 m (120 ft)
temperatures less than 20 oC (72 oF)
hard substrate such as rocky bottoms
bottom light intensities within 1% that of the surface.

Giant bladder kelp or Macrocystis is the easy to harvest for several reasons. The
fact that it is found in deep water habitat allows large harvesting boats to
operate more easily. The surface canopy can be harvested several times a
year without disturbing the submerged vegetative and reproductive parts
which are located below the harvesting levels thus ensuring the kelp will
continue to reproduce and the surface canopy will be regenerated by the
younger fronds growing below the surface.

In the early 1930's the algin-extraction industry was developed. Algin, a
highly efficient thickening, stabilizing, suspending and gelling agent.

The harvesting of kelp in the state is regulated by the California Department
of Fish and Game with the maintenance and improvement of the kelp beds
important considerations. The State of California has imposed a number of
restrictions on harvesting activities. Kelp harvesters are permitted to cut only
the upper 1.2 meters (4 feet) of the water column. This regulation is to limit
damage to the kelp's reproductive structures and allows vegetative regrowth from the unharvested fronds below the surface on cut plants. Stands
of kelp throughout the state are designated by number and some are leased
by harvesting companies while others remain open to anyone with a
harvesting permit. The kelp beds are leased for a period of 20 years. No
more than 25 square miles or 50% of the total kelp bed area, whichever is
greater, can be exclusively leased by one company.