How do sandbars get started?

The current closest to the ocean floor is moving offshore and dumps small piles of sand right at the wave break area. The sand accumulates to various degrees, and regardless it makes the water much shallower where you stand. Now, the sandbars that I am thinking of are very long and are parallel to the coastline. But, the same type of accumulation occurs in the open water, these are known as shoals. A sandbar is a type of shoal.

 

What makes the swirly tracks at the ocean edge?

What I think you are referring to is the trail of a moon snail, or sometimes called a sand snail. This univalve animal has a cinnamon bun swirled shell. The shell is extremely thick to protect itself from the ocean and other animals that may try to eat it.

If you try to pick it up – the animal will resist because of its suction like muscled foot planted in the sand. The snail has that muscled foot which makes it glide quickly through the sand. If you do pick it up and feel resistance – it is ok, the animal will “close its door” – or operculum – and hold in water and nutrients. And, of course, you will put it back right where you found it? Now, it you see some colored legs poking out – that’s a hermit crab. They may pinch – so put it back – quickly. Hermit crabs make their homes out of shells that are no longer homes to other animals…

Lastly, this is type of snail is the one that has the radula which drills into clam shells.

Do you have another great question? Check out www.beachchairscientist.com and let us know what you always ponder while digging your toes in the sand!

What does it mean to be a barrier island?

Theoretically, a barrier island is there to protect the mainland from harsh weather.

Barrier islands are a permanently exposed “mountains” from the bottom of the ocean made up of sand and rock and pebble. A lot of barrier islands are developed – as you drive to a barrier island you inevitably cross a bridge that is over an estuary (bay).

Two of my favorite barrier islands are Stone Harbor/Avalon in N.J. and Hutchinson Island in FL.

Do you have another great question? Check out www.beachchairscientist.com and let us know what you always ponder while digging your toes in the sand!

What lives in the spooky burrows on the beach?

The answer is appropriate for this time of year … those quarter-sized holes are the home the ghost crabs or fiddler crabs. Ghost crabs emerge to scavenger upon anything they can get including crabs or clams, bugs or insects, plants or dead stuff (detritus). The burrows are personal territories (i.e., not colonies like on Meerkat Manor). If one male tries to challenge another for his home what occurs is an interesting ritualistic “dance.” There is rarely actual contact and the better “dancer” wins. If you’re tanning on a beach blanket and hear tapping or bubbling noises under the sand, that’s the ghost crab either using their claws for digging or sounds from their gills as they breath. The burrows can be up to three feet deep.

ghostCrab

F1.mediumTop – Ghost crab burrow image (c) aquaessence.com, bottom – fiddler crab burrow image (c) jeb.biologists.org

In what way can a beach be compared to a desert?

…It’s Charismatic Microfauna!

Well, yes there’s the sand, but there is also an unrecognized and perhaps even shocking biodiversity that lies not quite below the surface.

Would you believe me if I told you that in a single handful of wet sand you could be holding a community of organisms equaling, if not exceeding, the diversity found in an Amazonian rainforest?

All too often we suffer from a bias of scale, but biodiversity includes all organisms, including the mega-, the micro- and the meiofauna.

So just who are the meiofauna?meio

They are the smallest animals on earth—some no larger than a grain of sand.

They live in ultra-micro habitats within habitats and make an excellent example of the complexity of ecosystems and the interconnectedness of life.

The meiofauna aren’t a kind of animal, but rather a size-class of animals that live (mostly) in and among aquatic and marine sediments. (Fully 25 animal phyla have representatives in the meiofauna and they boast some of the most unique and strange biological adaptations in the Animal Kingdom.)

Without a microscope and a little curiosity, you’d probably never notice they were there…but you’d certainly notice if they weren’t…

Among the roles meiofaunal animals play in their environment is that of the decomposer. Beaches without a strong meiofaunal component have a distinctive, sulphuric odor of decay.

The meiofauna provide even more proof that there will always be new discoveries to be made in the marine environment—not just for us, but for all of science.

The newest animal groups described have been meiofaunal—three entirely new phyla described in the last 25 years. Exploring the meiofauna opens a whole new world discovery for even the most jaded, know-it-all, marine biologist!

But we’ve only scratched the surface here. Check back often at beachchairscientist.com for more about some of my favorite meiofauna.

By Jim Wharton, Director, Center for School and Public Programs with Mote Marine Laboratory

Photo (c) Rick Hochberg

So what’s up with that sand stuck between my toes?

Sand is basically the tiny particles eroded from the mountains or rock formation closest to the beach you are standing on as well as some other bits and pieces. The three main ingredients common to all the beaches are: quartz, old shell parts, and decayed materials from the sea and land.

I saw the most interesting image of sand gradients going from really dark to really light as one traveled from Maine to Florida. Which makes sense since the chemical make up of those mountain ranges and the biological life in each of those areas is unique.

Someone did ask me if sand was a natural exfoliates our skins – and the answer is basically, yes. There are a lot of natural exfoliates out there and sand is one – in the sense that it helps to remove dead skin cells, like sponges you see for sale. Maybe not the most comfortable – but, certainly one of the most accessible if you get a burn (once mixed with water – it really cools you off, but looks gross).

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