Kelp forests are underwater ecosystems formed in shallow water (close to the shore) by the dense growth of several different species known as kelp.
Though they look very much like plants, kelps are actually extremely large brown algae.
Some species can reach heights (underwater) of 150 feet (45 m), and under ideal physical conditions, kelp can grow 18 inches (45 cm) in a single day!
As a result of this incredible growth, kelp forests can develop very quickly in areas that they did not previously exist.
Kelp thrives in cold, nutrient-rich waters. Because kelp attaches to the seafloor and eventually grows to the water’s surface and relies on sunlight to generate food and energy, kelp forests are always coastal and require shallow, relatively clear water.
Generally speaking, kelps live further from the tropics than coral reefs, mangrove forests, and warm-water seagrass beds, so kelp forests do not overlap with those systems.
Like those systems, though, kelp forests provide important three-dimensional, underwater habitat that is home to hundreds or thousands of species of invertebrates, fishes, and other algae and have great ecological and economic value.
Some species aggregate and spawn in kelp forests or utilize these areas as juvenile nursery habitat.
Large predatory species of sharks and marine mammals are known to hunt in the long corridors that form in kelp forests between rows of individual plants.
Though kelp forests are important ecosystems wherever they occur, they are more dynamic than the other systems mentioned above. In other words, they can disappear and reappear based on the oceanographic conditions and the population sizes of their primary herbivores.
Warmer than normal summers and seasonal changes to currents that bring fewer nutrients to kelp forests (both sometimes occurring naturally) combine to weaken kelps and threaten their survival in some years.
Strong individual storms can wipe out large areas of kelp forest, by ripping the kelp plants from the seafloor.
Large gatherings of sea urchins (a primary herbivore in kelp forests) can prevent kelp plants from growing large enough to form forests. The cycle between these so called “urchin barrens” and well-developed kelp forests is a well-studied phenomenon in regions that are favorable for forest formation.
Each of these natural alterations to kelp forest density or total area affects the community of invertebrates and fishes that live in this ecosystem.
Population sizes of many of these species (including some that are commercially important food species) depend on the success of kelp growth each year.
Significance:
It serves as a pertinent food source for a variety of marine creatures. Kelps are responsible for producing up to 60% of the carbon found in coastal invertebrates.
They also offer crucial services such as carbon sequestration and erosion control, according to scientists.
As a diverse invertebrate and fish ecosystem, they serve as a habitat for birds to forage.
It releases carbon into the coastal ecology, increasing its productivity.New biomass, detritus, and other materials are produced through primary production by kelp.
Facts About Kelp Forests
Kelp are not plants, but rather extremely large brown algae, and many different species of kelp make up kelp forests.
Some kelp species can measure up to 150 feet (45 m) long. If living in ideal physical conditions, kelp can grow 18 inches (45 cm) a day.
Kelp forests comprise one the ocean’s most diverse ecosystems. Many fish species use kelp forests as nurseries for their young, while seabirds and marine mammals like sea lions, sea otters and even gray whales use them as shelter from predators and storms.
Sea urchins can destroy entire kelp forests at a rate of 30 feet (9 m) per month by moving in herds. Sea otters play a key role in stabilizing sea urchin populations so that kelp forests may thrive.
Giant kelp is harvested from kelp forests and used as a binding agent in products like ice cream, cereal, ranch dressing, yogurt, toothpaste, lotion and more.
Threats to Kelp Forest
Climate change and human-induced stressors:
Kelps are increasingly threatened by climate change, eutrophication and shoreline development, among other human-induced stressors.
Destructive fishing practices, coastal pollution, and accidental damage caused by boat entanglement are known to negatively affect kelp forests.
Warming of oceans:
Warmer than normal summers and seasonal changes to currents that bring fewer nutrients to kelp forests combine to weaken kelps and threaten their survival in some years.
Bryozoa:
One such threat is from bryozoa, moss animals that grow as mats on kelps. They drive the seaweed to sink into the seafloor and disintegrate.
The bryozoa outbreak can be linked to high temperatures as high temperature and kelp density results in more bryozoan.
Dense kelp beds in warmer and less wave-exposed sites are more susceptible to bryozoan outbreaks.
Storms:
Strong individual storms can wipe out large areas of kelp forest, by ripping the kelp plants from the seafloor.
World Distribution of Major Kelp Forests:
Kelps cover 25 per cent of the world’s coastlines and provide food and shelter for fish, invertebrates and marine mammal species.
