Topic : Underwater forests in the Arctic are expanding with climate change
Topic in Syllabus :
Climate change is altering marine habitats such as kelp forests on a global scale.In Western Australia, eastern Canada, southern Europe, northern California and eastern United States, kelps are disappearing due to warming temperatures.
What are Kelps?
- Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera.
- They occur on rocky coasts throughout the Arctic. The longest kelp recorded in the Arctic in Canada was 15 metres, and the deepest was found at 60-metre depth (Disko Bay, Greenland).
Significance of kelps:
- Kelps have adapted to the severe conditions.
- These cool water species have special strategies to survive freezing temperatures and long periods of darkness, and even grow under sea ice. In regions with cold, nutrient-rich water, they can attain some of the highest rates of primary production of any natural ecosystem on Earth.
- More than 350 different species – up to 100,000 small invertebrates – can live on a single kelp plant, and many fish, birds and mammals depend on the whole forest.
- Kelp forests also help protect coastlines by decreasing the power of waves during storms and reducing coastal erosion.
Impact of climate change on under water forest
- As waters warm and sea ice retreats, more light will reach the seafloor, which will benefit marine plants. Researchers predicta northern shift of kelp forests as ice retreats.
- Genetic evidence reveals that most kelps reinvaded the Arctic from the Atlantic Ocean quite recently (approximately 8,000 years ago, following the last Ice Age).
- As a result, most kelps in the Arctic are living in waters colder than their optimal temperature. Ocean warming will also move conditions closer to temperatures of maximum growth, and could increase the productivity of these habitats.
Threats to Kelp
- Changes that are happening in the Arctic that complicate the picture. In Canada, Alaska, Greenland, Norway and Siberia, permafrost soils that have been frozen for thousands of years are receding by half a metre per year.
- Thawing permafrost and crumbling Arctic coasts are dumping sediments into coastal waters at alarming rates, which blocks light and could limit plant growth.
- The run-off from melting glaciers will also lower salinity and increase turbidity, which impacts young kelp.
Kelp Forest potential
- Kelp forests throughout the world play an important role in coastal economies, supporting a broad range of tourism, recreational and commercial activities.
- Kelp is making its way onto the plates of North Americans, and the kelp aquaculture industry is growing at a rate of seven per cent per year for the last 20 years globally (kelp is a coveted food source in many countries, full of potassium, iron, calcium, fibre and iodine).
- In the Arctic, Inuit traditionally use kelp as food and wild harvest numerous species.
- Arctic kelp forests provide a key example of the diverse responses to climate change. Predictive models and experiments suggest that Arctic coasts are in line to become one of the most impacted environments in the world under changing climate.
- Yet the possible expansion of kelp forests should provide new habitats for fish and other marine organisms, and enhance a suite of valuable ecosystem services along Arctic coastlines.
- This expanding resource may provide needed income to northern communities whose livelihoods are threatened by climate change and other impacts.
Arctic kelp forests provide a key example of the diverse responses to climate change. Elucidate