14th December, 2022 Environment
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Context: Ocean warming disrupts early-stage development of Giant Kelp, the largest marine algae that are intrinsic to sea life, leading to rapid decline in kelp forests across the world, a new study found.
- The world has lost much of its kelp forests in the last century to rising sea temperatures, but the mechanism of deterioration was not fully understood by scientists.
- The Giant Kelps reproduce by releasing single-cell units called spores that grow into ‘germ tubes’ that gather nutrients and develop into adults.
- At higher temperatures, spore release increased but “spore settlement, germination and germ-tube length” were negatively impacted, the researchers found.
- In the last 30 years, sea surface temperatures have gone up by 0.13°C per decade and oceans are expected to heat up by 1-3°C by the turn of the century, the scientists wrote. This condition threatens existing kelp forests as well, they warned.
- These large, fleshy brown algae are found along much of the world’s coastline. They nourish and shelter thousands of marine species. In the healthy state, they act as carbon sinks.
- But as they are damaged, they release much of the sequestered carbon into the atmosphere.
- Understanding the thermal threshold of spore and germling life stages of giant kelp is key for making predictions of how such a valuable ecosystem engineer will perform in decades to come, said Matthew Desmond from the department of marine science of the University of Otago.
About Kelp Forests:
- Kelp forests are under water areas with a high density of kelp, which covers a large part of the world's coastlines.
- They are recognized as one of the most productive and dynamic ecosystems on Earth.
- Smaller areas of anchored kelp are called kelp beds.
- Kelp forests occur worldwide throughout temperate and polar coastal oceans.
- In 2007, kelp forests were also discovered in tropical waters near Ecuador.
- In context, algal kelp forest combined with coral reefs account for less than 1% of global primary productivity.
- Physically formed by brown macroalgae, kelp forests provide a unique habitat for marine organisms and are a source for understanding many ecological processes.
- Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem.
- For example, kelp forests can influence coastal oceanographic patterns and provide many ecosystem services.
- However, the influence of humans has often contributed to kelp forest degradation.
- Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the overgrazing of kelp and other algae.