Dynamics of Jellyfish Blooms in Marine Ecosystems

Jellyfish blooms—episodic surges in medusa abundance—are ecological phenomena shaping marine food webs, biogeochemical cycles and coastal economies. These blooms emerge from the complex interplay of life-cycle transitions, environmental forcing and trophic interactions. Polyps, the benthic asexual stage, undergo strobilation to release ephyrae that grow into medusae, triggering bloom formation when conditions align. Seasonal temperature, salinity and nutrient regimes often modulate strobilation and medusa survival, while anthropogenic influences such as overfishing, habitat modification and eutrophication may indirectly alter the balance of predator–prey networks, favouring jellyfish proliferation. Once established, dense aggregations of medusae contribute substantial organic pulses—jelly-OM—that fuel microbial cascades, enhance carbon export and influence nutrient regeneration. Blooms also affect fisheries, tourism and public health, with ramifications for coastal management and climate feedbacks. A comprehensive understanding of bloom dynamics requires integration of observational time series, mechanistic experiments, mathematical modelling and molecular analyses, underscoring the global significance of jellyfish at the interface of marine ecosystem function and human well-being.

Research from Nature Portfolio

A key study has simulated the drift pathways of Portuguese Man-of-War swarms into the Mediterranean, revealing that exceptional wintertime wind patterns and ocean currents, rather than long-term climatic shifts, were responsible for the 2010 proliferation. This work refines our capacity to forecast episodic jellyfish swarms through high-resolution numerical modelling and highlights the sensitivity of bloom events to transient meteorological anomalies.

Dynamics of Jellyfish Blooms in Marine Ecosystems publication trend

The graph below shows the total number of articles in dynamics of jellyfish blooms in marine ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Bloom: A rapid increase in the abundance of medusa-stage jellyfish in marine waters.

Polyp: The sessile, asexual life-stage of scyphozoan jellyfish attached to submerged substrates.

Medusa: The free-swimming, sexual life-stage responsible for the characteristic jellyfish morphology.

Strobilation: The asexual segmentation process by which polyps produce ephyrae, the precursors of medusae.

Jelly-OM: Labile organic matter released by decaying jellyfish that fuels microbial metabolic networks in the water column.

References

1. Jellyfish detritus supports niche partitioning and metabolic interactions among pelagic marine bacteria. Microbiome (2023).
2. Filter‐feeding gelatinous macrozooplankton response to climate change and implications for benthic food supply and global carbon cycle. Global Change Biology (2023).
3. Molecular and cellular basis of life cycle transition provides new insights into ecological adaptation in jellyfish. The Innovation Geoscience (2024).
4. Environmental Control of Phase Transition and Polyp Survival of a Massive-Outbreaker Jellyfish. PLOS ONE (2010).
5. Portuguese Man-of-War (Physalia physalis) in the Mediterranean: A permanent invasion or a casual appearance?. Scientific Reports (2015).