Kelp Forest Ecosystem Dynamics and Responses to Climate Change

Kelp forests are highly productive underwater ecosystems dominated by large brown macroalgae that structure communities, support diverse food webs and provide critical ecosystem services. Their dynamics are governed by the interplay of physical factors such as light, temperature and wave exposure; biological drivers including grazing pressure, recruitment and interspecific competition; and oceanographic processes that regulate nutrient supply and dispersal. Climate change is altering these dynamics through rising sea temperatures, shifts in nutrient regimes, ocean acidification and increasing frequency of extreme events such as marine heatwaves. These stressors can reduce kelp growth and reproductive success, trigger shifts towards alternative states such as urchin‐dominated barrens, drive poleward range shifts and, in some regions, lead to local extinctions. The consequences cascade through coastal food webs, affecting fish, invertebrates and human communities reliant on kelp-associated fisheries, coastal protection and carbon sequestration. Understanding these processes is essential to inform restoration, conservation and sustainable management strategies in a rapidly changing ocean.

Research from Nature Portfolio

Recent global assessments have quantified the ecological and economic value of kelp-forest services, revealing that these habitats contribute hundreds of billions of dollars annually through fisheries production, nutrient cycling and carbon sequestration. Detailed analyses underscore their role as blue-carbon systems capable of removing substantial volumes of atmospheric CO₂ and supporting coastal livelihoods. Investigations into abrupt climate-driven regime shifts demonstrate how rapid warming and multi-stressor events can collapse kelp canopies by over 90% along extended coastlines, precipitating persistent urchin barrens and profound ecosystem and fishery impacts. Studies further highlight that variation in genetic diversity among kelp populations strongly predicts resilience to extreme heat events, with genetically diverse forests exhibiting greater physiological versatility and recovery potential, thereby moderating vulnerability to future climatic perturbations.

Kelp Forest Ecosystem Dynamics and Responses to Climate Change publication trend

The graph below shows the total number of articles in kelp forest ecosystem dynamics and responses to climate change across all publications each year (not limited to Nature Index journals).

Technical terms

Foundation species: Organisms that create or strongly modify habitats, supporting other species.

Marine heatwave: A prolonged period of unusually high sea surface temperature.

Urchin barrens: Areas of seabed where overgrazing by sea urchins has removed kelp canopy, leading to low productivity.

Blue carbon: Carbon sequestered by marine ecosystems such as kelp forests and seagrass beds.

Trophic cascade: A series of changes in ecosystem structure caused by alterations at the top of the food web.

Genetic diversity: The variety of genetic characteristics within and between populations of a species, affecting adaptive capacity.

References

1. The value of ecosystem services in global marine kelp forests. Nature Communications (2023).
2. Marine heat wave and multiple stressors tip bull kelp forest to sea urchin barrens. Scientific Reports (2019).
3. Genetic diversity and kelp forest vulnerability to climatic stress. Scientific Reports (2018).
4. Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective. Ecology and Evolution (2013).
5. Extreme Marine Heatwaves Alter Kelp Forest Community Near Its Equatorward Distribution Limit. Frontiers in Marine Science (2019).
6. Local Extinction of Bull Kelp (Durvillaea spp.) Due to a Marine Heatwave. Frontiers in Marine Science (2019).