Phytoplankton
Definition
Microscopic photosynthetic organisms that live suspended in the water column. Includes diatoms plus green algae, cyanobacteria, chrysophytes, dinoflagellates, and euglenoids. The full phytoplankton assemblage is more distinctive than diatoms alone.
- Composition
- Diatoms, green algae, cyanobacteria, chrysophytes, dinoflagellates, euglenoids
- Habitat
- Suspended in the water column
- Forensic advantage
- Full assemblage more distinctive than diatoms alone
- Field
- Drowning and aquatic scene analysis
Common questions
Why look at the whole phytoplankton assemblage instead of just diatoms in a drowning case?+
Diatom testing has long been the standard because diatom shells survive tissue digestion, but relying on diatoms alone discards information from other organisms present at the same site and time. Comparing the full assemblage, when it can be recovered, gives a more specific match to a particular body of water than diatoms alone.
What does matching phytoplankton in tissue actually establish in a drowning investigation?+
A matching assemblage supports that the victim inhaled water from a specific body of water while still alive, since active breathing is needed to draw organisms deep into the lungs and bloodstream, which helps distinguish a true drowning from a body placed in water after death.
Related terms
- Aquatic Macrophyte
- Vascular aquatic plants, including submerged, floating, and emergent species such as Elodea, Potamogeton, Phragmites, and Nymphaea. Fragments of these plants on a...
- Cyanobacteria
- Photosynthetic prokaryotic bacteria, often called blue-green algae. Form surface scums in warm, nutrient-rich water. Contain characteristic cellular structures (heterocysts, akinetes) identifiable microscopically....
- Limnological Profiling
- Building a characterisation of a water body using physical, chemical, and biological measurements. Forensically, the profile is the reference against which biological...
- Limnology
- The scientific study of the biology, chemistry, and physics of inland waters (lakes, rivers, ponds, wetlands). Its reference databases of species assemblages...
- Macroalgae
- Filamentous or thalloid algae visible to the naked eye, such as Spirogyra, Cladophora, Enteromorpha, and Chaetophora. They colonise sheltered margins, shallow water,...