THE OCEAN’S BEST-KEPT SECRET

Many people around the world are familiar with vibrant coral reefs and robust mangroves. These majestic ecosystems are popular, picturesque, and sustain the lives of humans and other organisms all around the world. However, there is another aquatic ecosystem that deserves all of this glamorous recognition as well: the humble seagrass meadow. 

Seagrass meadows were once terrestrial ecosystems, but during the age of the dinosaurs, these plants emigrated into the oceans, adapting as marine plants with aquatic pollination, neutrally buoyant seeds, and leaves that would thrive in saltwater [1]. Today, seagrass meadows usually dwell in shallow waters at depths of less than 10 feet, cover 300,000 square kilometers of the ocean floor, and are off the coast of at least 159 countries. They are home to a plethora of marine species, including seahorses, sea turtles, and dugongs [2], and also act as a nursery and feeding ground for other animals like manatees.  

Other than serving ocean life, seagrass meadows also serve humans. Seagrass meadows are outstanding carbon sinks. Although they only cover 0.1% of the ocean floor, they store up to 18% of the world’s oceanic carbon [2], contributing 10% of the ocean’s capacity to store carbon. These mighty carbon sinks absorb carbon 35 times faster than tropical rainforests [3]. Seagrass meadows also protect humans by absorbing wave energy, weakening tropical storms that damage coastal communities. Furthermore, seagrass meadows not only provide coastal communities with a vast food source, but also filter pathogens, bacteria, and anthropogenic pollution out of the seawater [2].  

With everything these humble servants do for life on earth, human activity is destroying seagrass habitats. Research shows that 7% of seagrass meadows are lost each year [2], and with this loss rate accelerating, it is comparable to the rate at which corals and rainforests are dying [3]. The main threats to seagrass meadow habitats are urban runoff, industrial runoff, agricultural runoff, coastal development, dredging, unregulated fishing and boating, and climate change. Although other aquatic ecosystems share some of these threats, seagrass habitats are among the least protected, with only 26% of seagrass meadows in protected waters [2]. 

Fortunately, there is hope for these modest meadows. Some scientists have taken notice of how resilient seagrass meadows can be. In 1999, a group of scientists planted 74.5 million eelgrass seeds into 536 restoration plots, covering about 1 square mile of the ocean floor. Today, that seagrass flourishes over 13 square miles. Other seagrass restoration projects are taking place around the world and having success, including indirect restoration like reducing runoff rates. Robert Orth, a marine ecologist at the Virginia Institute of Marine Science, explains that if seagrass is not “challenged by water quality, they can spread naturally very quickly” [1]. This not only promotes the restoration of seagrass meadows but also encourages more restoration projects to take place. 

Seagrass meadows, along with other aquatic ecosystems, are vital for ocean, animal, and human health. The best way to preserve these ethereal ecosystems is by taking preventative measures. Some simple things that can be done on an individual level to help protect and restore marine ecosystems like seagrass meadows include: reducing one’s carbon footprint, fishing and boating responsibly, understanding and following the laws in protected and unprotected waters, conserving water (this decreases runoff), switching to chemical-free solvents and disposing of chemical products correctly, only buying sustainably caught seafood, and donating to nonprofits that work to protect the oceans and environment.

Written by Danielle Turner

References:

[1] Courage, K. H. (2020, December). Why seagrass could be the Ocean's secret weapon against climate change. Retrieved February 28, 2021, from https://www.smithsonianmag.com/science-nature/seagrass-ocean-secret-weapon-climate-change-180976235/ 

[2] Protection of seagrasses is key to building resilience to climate change and disasters. (2020, June 08). Retrieved February 28, 2021, from https://phys.org/news/2020-06-seagrasses-key-resilience-climate-disasters.html#:~:text=The%20report%2C%20launched%20on%20World,of%20the%20world's%20oceanic%20carbon 

[3] Seagrass-secret weapon in the fight against global heating. (2019, November 01). Retrieved February 28, 2021, from https://www.unep.org/news-and-stories/story/seagrass-secret-weapon-fight-against-global-heating