Phytoplankton & Chlorophyll

March 21st, 2019

Phytoplankton & Chlorophyll

Phytoplankton are photosynthetic microorganisms that drift about in bodies of water.

Phytoplankton are divided into two classes:

cyanobacteria and algae

Phytoplankton can be found in fresh or saltwater.

Image: Collage adapted from drawings and micrographs by Sally Bensusen, NASA EOS Project Science Office

Fun fact, diatoms produce about half of Earth’s oxygen.

Scientists study phytoplankton due to their positive and negative influences on the natural world.

Positive Influences

Abundant Oxygen Production

Base of Oceanic Food Web

Carbon Fixation

Negative Influences

Harmful Algal Blooms

Fish Kills/Oxygen Depletion

Chlorophyll is a color pigment used as a photoreceptor during photosynthesis. It appears green because it only reflects the green wavelengths of visible light.

There are 6 different chlorophyll molecules.

All photosynthetic organisms, including phytoplankton, contain a form of chlorophyll called Chlorophyll A.

Different chlorophyll molecules absorb different wavelength ranges.

Phytoplankton can be measured using a chlorophyll sensor.

The sensors send a high-energy wavelength of light towards the phytoplankton biomass and then measure the returned wavelength.

These sensors use fluorescence to estimate phytoplankton levels based on the chlorophyll concentration in a body of water.

Cyanobacteria can be measured specifically due to their accessory pigments, phycocyanin and phycoerythrin.

Cyanobacteria sensors also rely on fluorescence to detect the pigment concentration.

Phycoerythrin sensors use a wavelength around 540nm and are applied in saltwater systems.

Phycocyanin sensors emit a wavelength around 600nm and are applied in freshwater systems.

Interesting Fact

Researchers from the University of Eastern Finland found a solution to multiple problems in using Chlorella vulgaris, a universal freshwater microalga. They analyzed biochemical compositions and fatty acid methyl esters (FAMEs) to evaluate how effectively the microalga produced bioenergy from pulp and aquaculture wastewater.


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