Kelp forests refer to a dense growth of different kelp species in nutrient-rich, cool, shallow water whose grouping resembles land forests. Smaller areas with kelps are known as kelp beds.
These underwater forests are lush, sunlight-dappled, and sway rhythmically to the moderate ocean current or waves where they grow.
They help manage climate change, provide habitat for fish and other organisms, and are a source of revenue for coastal communities.
However, they are under increased threat of extinction from climatic changes, herbivores or grazer populations, the decline in grazers’ prey, and human activities.
Learn what kelp forests are, their benefits, destruction, and conservation efforts.
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What are kelps?
Kelps are very large, brown algae (Phaeophyta) that resemble plants. However, they belong to the kingdom Chromista, not Plantae, and order Laminariale.
These organisms are primary producers. i.e., they use nutrients and sunlight to make food (photosynthesize).
However, they don’t have true leaves, stems, flowers, or stems. Instead, they reproduce via spores and attach to the substrate (rocks or cobbles) with holdfasts, i.e., tough, branched root-like structures.
Also, they have stiff stipes or rope-like branches that hold their palm-like blades. These organisms absorb nutrients with these blades and stipes.
Many kelp species have gas-filled sacs called pneumatocysts to remain buoyant and grow upward toward light.
According to NOAA, there are over 30 species of kelps. Giant kelp (Macrocystis pyrifera), bull kelp (Nereocystis leutkeana), and Kombu (Saccharina japonica) are the most popular.
Giant kelp can live for up to seven years. In contrast, bulk kelps are annuals, i.e., live for only a year. These two grow largest and quicker towards the light. Once on the surface, they will entwine to form canopies tens of meters thick.
Beneath the canopies, understory kelp species grow and resemble the land forest understory, i.e., smaller trees, shrubs, and grasses.
On the other hand, Kombu is a popular ingredient in Japanese, Korean, and Chinese cuisines.
Where do kelp forests grow?
Kelp forests grow in cool, shallow, clear, nutrient-rich waters that allow sunlight for photosynthesis or food.
Ideal temperatures are 10-18°C (50-64°F). But they can tolerate 5°C (41°F) in the arctic. Also, they can grow in depths of 20°C ( 68°F) in the tropics but won’t thrive well above 20°C.
On the other hand, kelp forests thrive at sea depths below 15-40 m (49-131) feet, i.e., where light can reach the seafloor to initiate life. However, some can grow at depths of 260 m (853 feet) in the Mediterranean Sea and Indian Ocean, where water is clear, and light can penetrate to such depths.
Secondly, they grow on rocky ocean floors or ones with large rocks, cobbles, and boulders where they attach. Otherwise, storms will easily reap them off.
Thirdly, they require areas with turbulence or moderate currents or waves to circulate nutrients, circulate propagules, and remove fouling organisms or mucus from fonds.
Finally, these forests grow further from the tropics, where mangrove forests, coral reefs, and warm-water seagrass beds thrive, i.e., don’t overlap with these systems.
Kelp forest organisms (animals and plants)
Kelp forests form the most diverse marine ecosystem. An ecosystem is a community of organisms (animals and plants) living and interacting in a certain environment.
Some of the animals and plants in this ecosystem include the following:
- Birds and mammals like shore birds, sea lions, seals, sea otters, terns, gray whales, great blue herons, gulls, snowy egrets, and cormorants.
- Fishes like black rockfish, leopard shark, lingcod, cabezon, perch, kelp bass garibaldi, rockfishes, finfishes, butterfish, clingfish, and señoritas. Also, wrasse, two-spotted goby, and pollack occur in these environs.
- Invertebrates like sea sponges, seamats, sea stars, sea squirts, soft corals, brittlestars, abalone, lobsters, sea cucumbers, sea urchins, nudibranchs, and red octopuses decorate crabs, sea anemones, snails and other mollusks and amphipods.
- Seaweeds such as red seaweeds.
Most of these organisms occur on holdfasts. However, some live in stipes or even blades like abalone and garibaldi.
Why are kelp forests important?
Some of the reasons why they are important include:
1. Support the most diverse marine ecosystem
Kelp forests offer food, shelter, protection, and a place to hunt for 30-70 species of organisms and 100s of individual animals. These include plankton, algae, invertebrates, birds and mammals.
For instance, forests will protect juvenile fish or other organisms from predators. Also, they provide a place to spawn or a nursery habitat—fishes like herring, Atka mackerel, lumpsuckers, and scorpionfish spawn in kelp beds.
On the other hand, larger predatory shark species and marine mammals will hunt here since some organisms hide in these forests.
2. Source of revenue
Nature reports that about $500 billion comes from Kelp forests. This money comes from kelp harvesting, commercial fishing, wastewater treatment, and recreational activities like diving.
i). Commercial use
Kelp has various commercial uses, including food production, textiles, biotechnology, and pharmaceuticals. This includes algin extraction used in cereal, yogurt, toothpaste, ice ranch dressing, lotion binding agent, and gelling agent in medicines and foods.
ii). Fishing
They host economically important invertebrates like red abalone, lobster, red urchins, prawns, crabs, sea cucumbers, and fishes like black rockfish, lingcod cabezon, kelp bass, garibaldi.
iii) Ecotourism
Income-generating ecotourism activities include watching marine mammals and birds, scuba diving, and kayaking. These places include Monterey Bay, Channel Islands National Marine Sanctuary, and California’s Catalina Island.
3. Carbon dioxide sequestration and water cleaning
They capture carbon dioxide from the atmosphere and store more carbon by over 20 times per acre compared to forests on land.
According to a study, kelp forests store about 61-268 megatons of carbon yearly. This can help reduce climatic change from global warming.
Furthermore, CO2 sequestration further helps reduce ocean acidification, which affects coral and shellfish.
Lastly, these forests remove polluting nutrients like phosphorus and nitrogen from water. This makes water clear and improves its quality. Also, they release oxygen that may reach the atmosphere.
4. Reduces coastal surges and waves
According to a study, they act as a buffer or protective layer against wave energy, reducing their size by about 60%. This reduces storm damage and protects coastal communities.
5. Part of marine food web or chain
Kelp forests are primary producers in the marine food chain or food web. They absorb nutrients like nitrogen from water and make food using the sun’s energy.
Other animals (primary consumers) feed from these foods, forming part of the food chain of larger secondary, tertiary, and quaternary consumers.
6. Source of food
Dried kelps serve as humans. They are nutrient-dense with omega-3 fatty acids, essential amino acids, vitamins A, B, C, and D, and dietary fibers. Uses include salad dressing, cakes, puddings, frozen foods, and dairy products.
Also, they feed aquacultured abalone.
Threats and destruction
Kelp forests compete with other plants and animals to settle and get light to grow. Also, they are very dynamic. Climate, oceanographic conditions, herbivore population, prey sizes, and disease can affect them.
On average, about 1.8% of kelp forests have been lost in the past half a century. For instance, 95% of Northern California and Southern Australia’s kelp forests are gone. This is the same case on almost every continent.
Their disappearance goes with the fish, invertebrates, birds, and mammals in the ecosystem.
Some of their threats include:
1. Climatic changes
Climatic changes, including from El Niño-Southern Oscillation (ENSO), can result in usually warm waters and currents poor in nutrients. ENSO happens every 2 to 7 years and can affect kelp forest growth negatively.
The warmer conditions may also attract warm-water sea urchins, which will mow these forests.
Lastly, strong storms can rip these forests from the seafloor and ear their fronts, making their canopies dense.
2. Grazers population increase
An increase or explosion in primary herbivore populations like sea urchins, abalones, and some fishes mow these forests, resulting in urchin barrens. Urchin barrens are urchin-dominated with little to no kelp forests.
When moving in herds, urchins can decimate 9 meters (30 feet) of this forest each month.
Some, like purple sea urchin hordes, can eat kelps faster than they produce. Also, they will eat stems detaching from the ocean floor and devour newly sprouting spores before they grow.
3. Predator absence and diseases
Sea urchins, predators like sea otters and sea stars, help check the population of sea urchins and grazing fish populations. Some lobsters and turban snails also prey on sea urchins.
Overfishing of sea otters or lobsters and sea star wasting diseases cause a decrease in the population of these critical prey. This will result in a population explosion of sea urchins that will mow down kelp forests.
4. Human activities
Commercial kelp harvesting, coastal pollution, overfishing, and boat destruction negatively affect kelp forests.
Two thousand nineteen data from FAO shows over one million tons of wild kelp is harvested, with Chile accounting for 40%.
Furthermore, pollution from silt, sludge, wastewater contaminants, and sedimentation from urban development activities can affect their growth negatively.
Another cause is agricultural runoff, which is rich in nutrients (eutrophication) and encourages invasive algae that choke kelp.
Lastly, introducing foreign invasive seaweeds, such as Wakame (Undaria pinnatifida) and Sargassum horneri, can choke these forests.
How to protect kelp forests
It is easier to protect than restore kelp forests. Also, these efforts are effective in near existing forests and destroyed ones. However, both approaches are essential in mitigating the decline.
Places like Australia, Norway, California, the USA, and Nova Scotia, Canada, have measures to protect and restore these forests.
Some of how kelp forests are being conserved include:
- Restoration efforts like 152 hectares Wheeler North Reef in San Clemente, Southern California.
- Research on and out-planting kelp forests that are more tolerant to higher temperatures caused by warmer waters, i.e., future-proof restoration.
- Reseed reefs, plant kelp, and create marine protected areas.
- Promoting sustainable and managed fishing and kelp harvesting using methods and scales that will not affect kelp beds in the long term.
- Enacting local and regional policies to prevent pollution, sedimentation, and coastal development and improve water quality in coastal areas.
- Control of herbivores like sea urchins by conserving natural prey like sea otters, including critically endangered species.
- Creating awareness, institutional support, and standardized monitoring of the status of these forests.
You can also help protect these forests by supporting conservation efforts financially, educating communities, and reducing your carbon footprint.
Also, you should ensure no leaking oil, pesticides, pet wastes, or trash falls on driveways, streets, or yards where it can get its way into the oceans via drainage systems.
Lastly, don’t discard plastic wasters and fishing gear into water bodies as they can tangle, or some sea animals can eat them.
Where are kelp forests found, or locations
Kelp forests occur on most temperate coastline shores and parts of the Arctic region. However, they don’t happen in Antarctica.
These forests occupy over 1/3 of the total coastlines and are prominent in Southern and Northern Atlantic and Pacific Ocean shores. Also, they occur in southern Australia in the Indian and Southern oceans.
Some countries with these forests include Norway, the UK, Eastern Russia, and other countries in Europe, northern and southern Africa, Chile, and Argentina in South America.
Other places are Greenland, New Zealand, and the Pacific coast of North America, from Alaska to parts of Baja California.
Some places to see kelp forests include
- Monterey Bay National Marine Sanctuary,
- Channel Islands National Marine Sanctuary,
- Greater Farallones National Marine Sanctuary,
- Olympic Coast National Marine Sanctuary
Kelp forests facts
- They can grow up to 18 inches or 45 cm in ideal physical conditions daily. Thus, they will quickly develop in areas they didn’t exist before. They start growing in spring when sunlight reaches the bottom of the sea, with autumn at their peak.
- Some species, like bulk kelp and giant kelp, can grow over 100 feet, with some going up to 262 feet from the ocean floor.
- Giant kelp is the most significant algae in the world.
- Sea urchins moving herds can mow as much as 9 meters of kelp per month.
- Predators like sea otters, sea stars, some fishes, and lobsters can help manage the urchin population that feeds directly on these forests.
- Kelp forests have declined by about 1.8% per year for the past half-century.