Why sharks matter. Their Top 5 ecosystem roles
- Naiara Budia Pinero
- 2 days ago
- 4 min read
Sharks may just be the most misunderstood and underappreciated creatures to roam our seas. But don't be deceived. Although they are painted to be scary, cold-blooded killers, that couldn't be further from the truth. The truth is they play a crucial part to the upkeeping and wellbeing of the marine ecosystem.
Why Sharks Matter. Here's the top 5 most important ecosystem roles that sharks play:
Regulate prey populations
As apex predators and top of the food chain fish, sharks help uphold a healthy balance in smaller fish populations by hunting on ill, weak or injured fish. As well as overpopulated fish and marine mammals. By doing this, sharks prevent any overcrowding or excessive numbers of any one fish species which could throw off the balance in the ecosystem. Shark presence is also a major indicator that scientists often use to signify a healthy and functional reef and get a better glimpse into ocean health!
Why this matters
By doing this, sharks also promote healthier prey populations and contribute and strengthen genetic diversity. They are like the superheroes of the ocean, helping in supporting biodiversity and protecting essential habitats.
Promote biodiversity
Sharks are a natural population control; by keeping mid-level predators in check, they allow low level plant eaters to thrive. These herbivores are a key part of keeping reefs abundant and healthy. Without them, the perfect balance would be sent spinning, and with it the worldwide coral reefs, home to the largest selection of diverse fish populations.
Why this matters
It has been found that, when shark presence and numbers decrease, the effects are almost instant. For example, in areas where shark numbers have declined, lower-level predators have surged in masses. These fish prey on the smaller herbivores that eat and keep algae numbers in check. Without these smaller fish, the algae can quickly infest coral reefs, preventing corals from growing and recovering from strains like warming waters and storms.
Maintain ecosystems stable
The existence and residency of sharks creates a fear-based system that influences the distribution and behaviour of coexisting prey species. This leads to more spaced out feeding and grazing patterns, which then takes any pressure off any one concentrated habitat like coral reefs and seagrass beds, and prevents any strain on food resources.
Why this matters
By keeping this balance in check, sharks help make sure that these habitats have more time and resilience to grow back and replenish. By doing so, they can recover quickly from any possible stress; like climate change, various feeding strains, and habitat destruction - often caused by human's overfishing tendencies.
Protecting marine habitats
Sharks help protect critical and endangered habitats like coral reefs, sea grass meadows and kelp forests. For example, by regulating the populations of grazers such as sea turtles, sea urchins, manatees and other kinds of fish, sharks prevent the over foraging of kelp and seagrass, which are crucial for carbon storage, which is another important part of maintaining habitat stability.
Why this matters
It has been found that healthy seagrass meadows can capture carbon from the atmosphere significantly faster than tropical rainforests. meaning that sharks are a vital part of climate regulation, helping the sea temperatures adapt and fight off global warming and climate change. Both of which are posing significant threats to our oceans and all its inhabitants.
Promote nutrient cycling
Sharks have a highly efficient digestive system that allows them to get the most nutrients out of their prey. Shark waste is a natural fertiliser for marine ecosystems. When waste is produced smaller marine organisms, like fish, feed on the remaining undigested nutrients. This process not only provides a direct food source for these smaller fish but also contributes to the overall nutrient cycling in the ocean.
Why this matters
When sharks that usually feed in deeper waters return to shallower reefs, they bring nutrients back from foreign feeding grounds to coastal environments. For instance, studies have shown that populations of grey reef sharks can contribute massive amounts of nitrogen to reef ecosystems on the daily. Thus, supporting the overall health of corals and other low-level organisms of the food web. These nutrients nourish algae and marine plants such as kelp, and plankton. Both of which are vital to the food web and to maintaining that perfect balance of the marine ecosystem.
Saltwater seas cover about 97% of our Earth and without sharks to keep our oceans stable and functioning like a well-oiled machine, marine life as we know it would be complete chaos, likely leaving our seas vulnerable to fall to climate change and other disasters. So, while their reputation isn't the cleanest, sharks truly are the superheroes of the ocean.
Writter Bio:
Naiara Budia, 16 — I love travelling, reading, socialising, and making new friends, especially when it means pushing myself out of my comfort zone. The ocean is a magical and fascinating place, that holds a special presence over my life and am deeply passionate about. Sharks, in particular, are such beautiful and powerful presences, and I want to do whatever I can to help protect them and keep the ocean thriving
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