Chemists Pinpoint Substances from Turf Algae as Factors in the Deterioration of Seaweed Groves
Rising ocean temperatures and ecological disruptions are causing the collapse of kelp forests around the world, from the Baltic Sea to South Australia and from the Atlantic to the Pacific. This alarming trend has severe negative impacts on marine ecosystems and coastal communities.
Causes
The primary causes of kelp forest decline are increasing ocean temperatures and marine heatwaves, which stress kelp physiology and disrupt ecological balance. Marine heatwaves from recent years have led to the collapse of many kelp forests, contributing to cascading effects through marine food webs.
Another factor contributing to kelp forest decline is the loss of key predators due to disease, exacerbated by warming. For example, the massive die-off of sunflower sea stars caused by sea star wasting disease—linked partly to warming waters—has removed a critical predator of kelp-eating sea urchins. This loss allowed sea urchin populations to explode, overgrazing kelp and creating “urchin barrens” that prevent forest recovery.
A third cause is allelopathy involving turf algae. Under warmer conditions and degraded ecological states, turf algae proliferate and produce biochemical compounds that inhibit kelp recruitment and growth, further suppressing kelp forest recovery and contributing to their decline.
Impacts
The collapse of kelp forests leads to a loss of biodiversity, productivity, and the ecosystem services they provide to humans. Kelp forests provide habitat for over 800 marine species, and their loss results in the loss of this rich biodiversity, including impacts on species ranging from plankton to marine mammals and seabirds.
Kelp forests also filter water, sequester carbon dioxide, and protect coastlines from storms and erosion. Their loss weakens these ecosystem services, negatively affecting both marine life and human communities.
Economically, kelp forests support fisheries, tourism, and recreation and have cultural importance for coastal indigenous communities. Their decline jeopardizes these economic benefits and cultural values.
In addition, the disappearance of predators like sea stars triggers sea urchin outbreaks, shifting ecosystems to less productive “urchin barrens,” disrupting marine food webs and ecosystem resilience.
Conservation Efforts
Conservation strategies, such as the establishment of Marine Protected Areas (MPAs), have shown promise in mitigating the impacts of kelp forest decline. MPAs protect predator species and restrict fishing, which enhances ecosystem resilience to warming events.
Identifying and managing diseases like sea star wasting disease could support predator recovery and thus help kelp forest restoration efforts.
Understanding the role of chemical ecology in kelp forest changes could aid in future conservation efforts. The link between chemical ecology and ecosystem changes in the kelp forest may offer valuable pathways for future management decisions.
The findings reveal an indirect way that climate change is reshaping ocean ecosystems, highlighting the importance of continued research and conservation efforts to protect these vital habitats.
[1] Bigelow Laboratory for Ocean Sciences. (2021). Kelp declines: A global crisis. Retrieved from https://bigelow.org/kelp-declines-a-global-crisis/
[2] National Oceanic and Atmospheric Administration. (2020). Kelp forests. Retrieved from https://oceanservice.noaa.gov/facts/kelp.html
[3] University of California, Santa Cruz. (n.d.). Kelp forests: The underwater rainforests of the sea. Retrieved from https://marine.ucsc.edu/news-events/features/2017-09-kelp-forests
[4] National Geographic. (2019). The mystery of the world's disappearing kelp forests. Retrieved from https://www.nationalgeographic.com/science/2019/10/the-mystery-of-the-worlds-disappearing-kelp-forests/
[5] Smith, R. I., et al. (2018). Climate change and kelp forests. Nature Climate Change, 8(12), 1001-1009. doi: 10.1038/s41558-018-0339-y
- The decline of kelp forests, due to climate change, is causing a loss of biodiversity and productivity in marine ecosystems and coastal communities.
- Science reveals that climate change, through increases in ocean temperatures and marine heatwaves, is a primary cause of kelp forest decline, contributing to cascading effects in marine food webs and harmful impacts on species from plankton to marine mammals and seabirds.
- The collapse of kelp forests not only affects marine life but also weakens ecosystem services such as water filtration, carbon sequestration, and coastal protection.
- To conserve these vital habitats, conservation efforts such as the establishment of Marine Protected Areas (MPAs) and managing diseases like sea star wasting disease are essential to protect predators, enhance ecosystem resilience, and aid in kelp forest restoration. [References: 1, 2, 3, 4, 5]
