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The benefits of turtles on the ecosystem.

© Marie Fontaine -

🐢 Sea turtles play a central role in maintaining a healthy ocean. They are essential to the biodiversity of the ocean and contribute greatly to the health of ecosystems.

Unfortunately, the significant and ongoing decline of sea turtles is causing major changes in our oceans.

Here are the benefits of different turtle species:

👉🐢 The green sea turtle

The green sea turtle helps maintain healthy seagrass beds by grazing on the sea grass. Through this constant grazing, the seagrass beds increase their nutrient content and the productivity of their blades.

Tortue verte broutant de l'herbe
Green turtle grazing on grass.

The reduction of green turtles population leads to invasive vegetation, interfering with the currents: light can no longer reach the sea floor. All this causes an increase in decomposition, which leads to the growth of slime molds: the seabed becomes full of algae, fungi, micro-organisms and invertebrates.

👉🐢 The hawksbill sea turtle

Tortue imbriquée
Hawksbill Turtle.

This species is omnivorous and eats everything, but its favorite food remains sea sponges. And this is a good thing, because sea sponges fight with corals to gain space on the reef and thanks to these turtles, the proliferation of sea sponges remains under control for now.

👉🐢 The leatherback sea turtle

It is the largest of all species of turtles. It lives in all oceans and can reach 2m in length and weigh up to 700 kg!

Tortue Luth mangeant une méduse.
Leatherback turtle eating a jellyfish.

It feeds mainly on jellyfish: it eats a lot of them, about 200 kg per day!

This makes this turtle one of the main predators of jellyfish throughout the oceans. Its role is thus essential in the balance of the marine ecosystem.

If the leatherback population decreases, the jellyfish population increases strongly. In addition, jellyfish feed on fish eggs and larvae, which prevents the recovery of fish stocks in the long term.

All this has led to new changes in the dominance of species, jellyfish passing before fish!

🥚🐢 The nesting of sea turtles also plays an important role in the ecosystem:

Turtle eggs
Turtle eggs

Baby turtles born on the beach.
Baby turtles born on the beach.

Sea turtle eggs provide essential nutrients such as nitrogen, phosphorus and potassium, which enter the beach dune ecosystems:

- If the eggs hatch, nutrients are left in the shell and embryonic fluid.

- If the eggs do not hatch, even more nutrients enter the food chain, some of which are taken up by plants. Others will be eaten by small organisms that live in the sand.

Six of the seven species of sea turtles are threatened or endangered due to human actions.

The main causes:

- Sea turtles get caught accidentally in fishing nets.

- Increased construction, tourism, boat traffic, dredging and other environmental impacts have all had a detrimental effect on the natural habitats that sea turtles use for nesting.

- Poaching: their shells are highly sought after.

- Marine pollution, microplastics, fishing equipment...

- Climate change: the warming of air temperature leads to warmer water and sand temperature. This increase in temperature results in fewer male pups and disrupts efficient reproductive patterns.

🐬🪸🌅 Now it is up to all of us to realize the importance of this fight. When protected, sea turtles can support both the conservation of our seas and the development of other marine species.

🐢🐟🪸 They also play an important role in maintaining the balance of the food web. A food web is the set of food interactions between living things in an ecosystem.


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