What does the future hold for seagrass?

seagrass

What does the future hold for seagrass? Benjamin Jones considers the issues facing these valuable meadows in this BBC Earth Blue Planet 2 blog post.

The savannahs of the seas – our humble seagrass meadows – are in peril.

In its Green Seas episode, Blue Planet II introduced us to seagrass meadows. Scarcely touched upon compared to coral reefs, mangroves or kelp forests, we learnt about the vast potential of these underwater grasslands – from their ability to take carbon from our atmosphere, to providing habitat for charismatic marine life.

But seagrass meadows are much more than this. We would need a whole new landmark series to truly convey how vitally important these habitats are for biodiversity, people and the planet!

Our understanding of the importance of these meadows is increasing. Recently we’ve discovered how seagrasses filter bacteria from coastal waters, helping to keep both people and coral reefs healthy. We also now know that seagrass meadows are possibly the most under-appreciated fishing habitats on earth, securing food supply and livelihoods.

Seagrass meadows are a home, source of food and a feeding ground for numerous species of fish, invertebrates, reptiles, birds and mammals. They protect our shores from erosion, trapping sediment in place and slowing currents and producing oxygen that we breath.

In peril

They truly are one of the ocean’s heroes. Not the hero our planet deserves, but the hero our planet needs. Our green knight if you will.

Despite all this, our seagrass meadows are in peril – unacknowledged and never the poster child of ocean conservation.

What this lack of understanding has resulted in is a habitat in a state of emergency. From the shores of the UK to uninhabited islands in the Indian ocean, the tell-tale signs of man’s impact on these meadows is visible.

We simply don’t know how much seagrass there is globally. This also means we don’t know how much we’ve lost, best estimates suggest that since the 1980s we’ve lost over 35%. That equates to around a football field every hour.

While we are distracted by stories of deforestation and river pollution, the threat we present to seagrass remains largely invisible.

Vast plumes of nutrient and sediment rich water flood onto our coastal seagrass meadows every day. Nutrients cause eutrophication, which is an excessive input of nutrients, frequently caused by run-off from the land.

Unlike land plants, seagrass meadows are not limited by nutrients, but are limited by light. This means that these massive amounts of nutrients cause opportunistic microscopic algae, called epiphytes, to smother seagrasses, preventing the plants from obtaining food through photosynthesis.

Read the full blog post at BBC Earth.

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