DREW HARVELL: Seagrass beds filter out a lot of bad coastal pollution and improve health for both people and the animals that live in them. This study is important, because it shows positive steps that we can take to improve the health of coastal ecosystems. This is a study that we ran in Indonesia. It was led by my post-doc, Dr. Joleah Lamb.
And what we did there is actually quantified the levels of bacteria that are from human sewage. And we showed that the levels were drawn down when the water passed over a seagrass bed, as compared to the same water or a control site that didn't pass over a seagrass bed. And this was replicated at four different islands all nearby, so very convincingly showed this drawdown of the fecal bacteria.
Then Joleah and her team-- and these were a team of Indonesian scientists we've been working with for over a decade here-- then went back and completely sequenced the bacteria that were in that water to not only show that one fecal coliform declining over the seagrass bed, but reductions in some very significant bacteria that are known to cause diseases in invertebrates, like corals and fishes.
And some of them are also relevant for human health. The final piece of the study was to look at a component of the health of the environment. And so what Joleah and her team did is they actually measured the levels of disease in corals inside and outside seagrass beds, and showed that the corals were healthier inside the seagrass beds.
So, again, with less nutrient pollution, less actual pathogenic bacteria in the water the corals themselves were healthier. We've spent a couple of decades, it seems like, studying things dying. We get called rapidly to outbreaks of coral disease, outbreaks of starfish disease, outbreaks of seagrass disease.
And at some point, we kind of got fed up with that and really wanted to take a more positive turn. What can we do to make things stop dying and be more healthy? And so we're really pleased with this study, because it's a positive step forward. It really shows that an ecosystem-- a natural ecosystem like seagrasses can be good for not just the health of corals, but also people. And we're really happy about that.
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Seagrass meadows—bountiful underwater gardens that nestle close to shore and are the most common coastal ecosystem on Earth—can reduce bacterial exposure for corals, other sea creatures and humans, according to new research published in Science Feb. 16, 2017. Drew Harvell, Cornell professor of ecology and evolutionary biology and an Atkinson Center fellow, describes how this ecosystem works. Credit: AAAS.