What's the best way to clean up a beach?

Marine biologist Danni Green tell Chris how we can boost our beaches. 

Danni - I think the first place you could start is to get involved with a local coast watch/litter watch group and go out and collect litter and marine anthropogenic debris, so most of that would be plastic.

In terms of beach regeneration and replanting of angiosperms, and algae, and things like that, it’s a lot more complicated and difficult, and there’s been a lot of work done on this. I’m assuming the beach he’s talking about used to have seagrass in the first place, because if it didn’t, you shouldn’t really go in and mess with a habitat - it is what it is. If it’s a sandy beach it’s a sandy beach and if it doesn’t have seagrass on it that’s fine.

A lot of the seagrass beds have been destroyed by people and the quality of these habitats have been degraded. They’re really important nursery grounds, they’re really important for ecosystem services, and ecosystem functioning.

In terms of restoration, there was a meta analysis about this recently that found that the most important thing you can do with restoration of seagrass habitats is to make sure that the habitat is in a good state already, so making sure there’s not a lot of litter and other pollutants. So you clean it up first and then you replant, and you want to replant in quite a big quantity, so I’m not sure that one person on their own could do this. This is something that you need a whole team to do. They found that the larger quantity that you replant, and if you also replant with a lot of genetic diversity, then you’ve got a greater chance of the survival of the shoots, increased productivity, biomass, and healthier seagrass.

Chris - There was a paper came out quite recently showing that if you have these seagrasses they seem to have some kind of sterilizing effect on the water, in terms of pathogen sterilization. They remove bacteria which we would regard as harmful, as pathogens, from the water, and the levels of these pathogens in areas where there were no seagrasses were perhaps an order of magnitude higher.

Danni - Oh OK, I’ve not actually seen that. I wonder if that’s because of the microbial communities on the actual seagrass itself?

Chris - They said they don’t know and they speculate that it appears that perhaps the microbiome on the plant is influencing things. Or that the other species which are attracted to live in the seagrasses themselves have some kind of anti-microbial, anti-pathogen effect.

Danni - And in the sediment beneath the seagrasses as well. Because they’re one of the few marine plants that are going to create a complex habitat beneath the surface of the sediment too.

Chris - But the bottom line is if we mess the environment up, we do so at our peril and we probably need to be a lot more careful about better stewardship of our planet don’t we really, that’s the bottom line?

Danni - Yes. I think that’s definitely true. I think it’s very good that people are asking these questions too.