We have now entered the month of December and most of the docks and boats along the coast are now sitting on dry land. It always makes me sad to see all those lonely piers sticking longingly out into the water. But, it is also a neat opportunity to see all of the strange marine life that grows on things that float.

If you find yourself walking by any boatyard, you’ll smell their presence. But if you’re curious and brave enough to look closely at them, you will see a veritable tide pool’s worth of life.

You are likely to find barnacles and mussels, or if you’re lucky you might also see a lone sea star or one of a variety of odd squishy colonial organisms that look more like plants than animals. There are tunicates that form a rubbery often bright orange or golden green coating and bryozoans otherwise known as “moss animals” because of their plant-like appearance and marine sponges forming strange volcanic shapes in bright yellows and reds.

Add to that the assortment of marine plants and you have an impressive crusty array creating the strong scents wafting from hauled docks.

So why are there so many of them stuck to these docks?

Many marine organisms just need a home. Much more of the ocean environment is fluid than solid, so space is at a premium. Most marine life begins life as tiny plankton floating around in the water. But at some point, they need a place to stick in order to transform from free-floating microscopic beings into the forms and shapes we recognize. If you read my column about whales a couple of weeks ago, you might remember that whale lice stick themselves to whale skin in odd white patches, riding along on their long migrations.

Fortunately, it isn’t a big deal to have some crusty creatures stuck to dock floats. It doesn’t tend to impact their functionality much and instead provides an upclose environment to see much of the marine life that can otherwise be elusive. And at the end of the season, most of the organic matter dies and falls off as the docks lie fallow in the fields. Or if they are heavily covered, they can be power-washed to blast off the tenacious remains.

But, boats are another story. If you look around, you’ll likely see many shiny-topped boats shrink-wrapped to protect them from winter’s elements. And their bottoms are probably pretty clean.

How can that be? Boats, like docks, can also easily become “fouled” or covered with marine life. While a dock that has become home to these organisms may be a focus of curiosity, a boat that is fouled is a problem. Think about trying to swim through the water in your clothes — not so speedy. The same principle applies to a boat trying to move through the water covered in taggers on.

And unless you want to send in a crew of divers equipped with scrub brushes on a regular basis, you’ve got to find a practical solution. Long ago, sailors put sheets of copper on the bottoms of their boats, having discovered that it kept off the sea life. But, you can imagine this was expensive and not terribly practical.

Fast-forward a bit and people figured out how to mix various compounds into paint and, voila — anti-fouling paint. Several “biocides” have been tried including mercury, arsenic, TBT (tributyltin), and DDT. You may recognize DDT from my recent column about bald eagles as the toxic chemical that caused thinning of eggshells and drastically reduced their population in the 1960s.

The others on the list likely raise red flags as well as they, too, are highly toxic. That’s certainly why they prevent fouling, but they also kill other marine life beyond their targets. After TBT, the most common of these, was banned in 1995, marine engineers tried using copper again, mixing cuprous oxide, a much less harmful additive, into paints.

Looking to nature for additional solutions to minimize additives, they wondered if they could mimic the sloughing activity of animals that experienced similar build-up. This is much like humans shedding their skin. If you’ve gotten paint on your skin and haven’t been able to wash it off, you know you can wait a few days and your skin will naturally slough it off. Why not sloughing paints?

These paints, known as ablative or self-polishing paints, are made of a soft rosin binder and a low copper content and are designed to shed light layers through the season, releasing just a bit of new biocide with each layer.

It’s always fascinating to see how people have learned to be better stewards of the environment by studying nature itself and heartening to see examples of improvements that make a difference to our local marine environment. So, take a moment to look at those stinky docks and appreciate how we have learned to treat our boat bottoms so that all that marine life continues to thrive.

Susan Olcott lives in Brunswick, with her husband and 7-year-old twin girls. She earned her M.S. in zoology studying the lobster fishery in New England. She then designed education programs for the Scripps Institute of Oceanography and taught biology to military personnel in Sardinia, Italy before returning to Maine to work on ocean planning for The Ocean Conservancy. She is now a freelance writer and currently writes about coastal issues for the Harpswell Anchor and The Working Waterfront and about local foods for the Brunswick Topsham Land Trust and Zest Magazine. In addition, she helps local schools pursue educational grants and writes children’s book reviews for the Horn Book’s family reading blog as well as for her own blog: susanolcott.wordpress.com.