Thalassiosira weissflogii - Centric Diatom for Marine Aquaculture

Scientific Classification

Kingdom: Chromista | Phylum: Bacillariophyta | Class: Mediophyceae | Order: Thalassiosirales | Family: Thalassiosiraceae | Genus: Thalassiosira | Species: T. weissflogii

Thalassiosira weissflogii Profile

Thalassiosira weissflogii represents a centric diatom species measuring 8-20 micrometers in diameter, featuring characteristic circular frustules (silica cell walls) with radial patterning visible under microscopy. This marine diatom typically grows as single cells rather than chains, distinguishing it from related species. Has become increasingly important in marine aquaculture research and commercial applications.

Nutritional Characteristics

Protein Content: 30-42% dry weight Lipid Content: 15-25% dry weight EPA Content: 25-35% of total fatty acids Fucoxanthin: High diatom carotenoid content Silica Content: Significant frustule silica Sterols: Rich in diatom-specific sterols

Marine Aquaculture Applications

Rotifer Production: Thalassiosira serves as excellent nutrition for marine rotifer culture (Brachionus plicatilis, B. rotundiformis). The diatom's size and nutritional profile support high rotifer reproduction rates and produce nutritionally superior rotifers for fish larviculture.

Copepod Diet Component: Larger calanoid copepods including Acartia tonsa, Centropages typicus, and Pseudodiaptomus pelagicus graze efficiently on Thalassiosira cells. Provides balanced nutrition supporting copepod egg production and nauplii development.

Shellfish Aquaculture: Juvenile oysters, clams, and mussels utilize Thalassiosira effectively, though less commonly used than smaller diatoms for early larval stages due to larger cell size.

Aquaculture Research Model: Serves as model organism in marine phytoplankton research, ecotoxicology studies, and ocean acidification experiments due to well-characterized growth and available genomic sequence.

Cultivation

Optimal Culture Conditions:

• Salinity: 25-35 ppt, optimal 30-33 ppt
• Temperature: 15-25°C, optimal 18-22°C (59-77°F)
• pH: 7.8-8.8, optimal 8.0-8.5
• Light: 100-250 μmol photons m⁻² s⁻¹
• Silicate: Essential for frustule formation (>2 mg/L)
• Growth Rate: Doubling time 18-30 hours

Culture Medium: Requires silicate-enriched marine media including F/2+Si or Guillard's f/2 with additional sodium silicate. Insufficient silicate limits growth and causes cell deformities.

Reef Aquarium Considerations

Direct Coral Applications: Some large-polyp stony corals and certain soft corals consume Thalassiosira, though smaller phytoplankton species generally more appropriate for most coral feeding.

Copepod Population Support: Contributes to diverse phytoplankton communities supporting mixed copepod populations, particularly benefiting larger copepod species.

Silicate Considerations: Regular additions of silicate-rich diatom cultures introduce silicate into reef aquariums, potentially fueling nuisance diatom blooms on aquarium surfaces. Requires consideration when using diatom phytoplankton in reef systems.