Harmful algal & jelly-fish blooms
Harmful algal & jelly-fish blooms
Harmful Algal Blooms (HABs)

Harmful Algal Blooms (HABs) attract scientific interest due to their increase of duration and intenseness worldwide. HABs have serious impacts on coastal ecosystems, public health and economy.

Many harmful algae are microalgae that produce toxins inside their cells, which can accumulate in soft tissues of shellfish and fish. The consumption of intoxicated seafood can cause dangerous human poisonings and therefore HABs provoke persistent closures of shellfish harvest.

Dinophysis cells during a toxic bloom in Thermaikos Gulf
Dinophysis cells during a toxic bloom in Thermaikos Gulf

The most frequent HABs in Greece are located in Thermaikos Gulf, Maliakos Gulf, Gulf of Kavala and Saronikos Gulf.

For example, a bloom of the toxic phytoplankton species Chattonella in Maliakos Gulf reached concentrations of more than 1 million Chattonella cells per liter of seawater and killed many tons of commercial fish with serious economic losses.

 Cultures of toxic Pseudo-nitzschia multiseries
Cultures of toxic Pseudo-nitzschia multiseries

HCMR conducts research on HABs covering various fields:

  • Coastal monitoring in hot-spots of frequent blooms and aqua farms
  • Shifts in phytoplankton diversity and dynamics of functional groups
  • Responses of HABs to nutrient pulses, pollution and global change with in-situ and laboratory experiments
  • Transfer and impacts of toxic microalgae in different compartments of marine food webs, eg shellfish, zooplankton, resting cysts
  • Cultures and biomass upscale system for biotechnological applications of harmful microalgae
  • Downstream services and earth observation tools for algal blooms detection and eutrophication monitoring
  • Indicators for the assessment of HABs frequency and extent in the frame of the EU Marine Strategy Framework Directive (MSFD) monitoring



Incubation rooms, well equipped laboratories and a microalgae culture collection are key tools in HCMR for HABs research. HCMR supports also actions for public awareness on HABS and collaborates with Public Safety and Port authorities of the Greek State, Associations of fish-farmers and mussel-farmers to consult them on bloom events in coastal areas of the country.