Tidepools!

Last week I participated in Marine Biology camp for high school students in Bodega Bay California.  Students collected animals from the tidepools and mudflats, took them back to the lab to observe them and then designed and conducted their own experiments.  It's so fun to get the chance to approach science again from this basic level of fascination and curiosity which is what drove me to study biology in the first place.  Some of my earliest memories are of exploring the tidepools of Islesboro, Maine finding muscles, barnacles, green sea urchins, brittle stars and crabs.  I would collect shells and seaglass which seemed like mysterious gifts from an unknown world.

Rocky Intertidal habitat in Big Sur, California.  Picture by Vanessa Miller-Sims

Tidepools are special place at the interface of land and sea and the organisms that live there must deal with living in an ephemeral habitat that is constantly changing in both time and space.  The intertidal zone is defined is the area that is out of the water at low tide but completely covered at high tide. Organisms living in this environment are exposed to wave action, changes in temperature and salinity, exposure to air and sun in addition to competition for space with other organisms and predation.  The intertidal is divided into zones depending on how much of the time the organisms that live there are submerged.  Organisms that live in the highest part of the intertidal zone are submerged for the least amount of time and must have adaptations to avoid drying out while the lowest part of the intertidal is submerged most of the time and thus provides the most stable habitat.

Barnacles in Garrapata State Park in Big Sur.  Picture by Vanessa Miller-Sims

These barnacles are not covered by water and as you can see they are closed fast to keep them from drying out.  When the tide rises and they are once again covered they will open up and feed on small particles suspended in the water.

Big Sur Tidepool. Picture by Vanessa Miller-Sims

A look into a submerged tidepool shows anemones snails and coralline algae.

A good read for lovers of Monterey Bay

I just finished reading a book called The Death and Life of Monterey Bay A Story of Revival by Stephen R. Palumbi and Carolyn Sotka.  It was a fun, interesting and quick read that I would definitely recommend to anyone who has visited and been enchanted by Monterey Bay or who is interested in marine conservation.  The first time I visited Monterey and Pacific Grove I immediately experienced it as a magical place full of history as a seaside fishing town and replete with natural beauty and sea critters.  The Monterey Bay Aquarium does an amazing job of showcasing the diverse and plentiful marine life of Monterey Bay and I love gazing out watching the sea otters float on their backs in the kelp.  The aquarium is built within an old cannery building on Cannery Row and I had known that the canneries once fished almost unfathomable numbers of sardines out of the bay before the fishery collapsed.  However, before reading this book I had not fully understood the extent of the environmental devastation that Monterey Bay had endured.  During the course of the 19th and first half of the 20th century the bay's resources were exploited one by one.  First the otters were hunted to the brink of extinction (and were in fact thought to be completely extinct), followed by California gray whales and abalone.  By the time the canneries started up the bay was already a greatly changed place.  The canneries not only fished out the sardines but also released large amounts of pollution into the bay and apparently the rocky shore was covered in rotting fish and flies.  Today Monterey Bay is an uplifting testament to the fact nature can regain a foothold when we leave a place alone and implement smart management.  The biggest change to Monterey Bay has been the return of the sea otters which have allowed kelp forests to flourish by keeping herbivorous sea urchin and abalone at bay.  The kelp in turn provides habitat for numerous fish species and allows a whole ecosystem to flourish.  The book tells the story of the rise and fall of Monterey Bay and the characters that have inhabited its shores over the course of the last 200 years.  

Keep those mozzies (mosquitoes) away!

Mosquitoes are a fact of life in the summertime but have you ever wondered how they track us down so quickly?  We've all had the experience where we're enjoying a nice summertime picnic and as soon as dusk arrives the mosquitoes show up one by one and start attacking.  How do they find us so quickly?  Mosquitoes are attracted to carbon dioxide, which seems a little unfair.  We release carbon dioxide every time we breathe out and to be even more tricky mosquitoes are specifically attracted to intermittent pulses of carbon dioxide.  Mosquitoes can follow carbon dioxide odor upstream to it's source (us).  This is always particularly clear to me when I am camping and I wake up in the morning to see both the condensation on the tent surfaced caused by my breath and the mosquitoes longingly pressed up against the screen of the tent.

Picture by JJ Harrison found on Wikipedia.org

Mosquitoes and other animals (including us) perceive a smell when small molecules in the air bind to a receptor and activate an olfactory neuron which then passes the message on to the brain.  Mosquitoes and other bugs have these receptors on an antennule on their head.  Receptors bind molecules based on their shape and chemical composition.  Most receptors are not perfect if a molecule is similar in shape to the intended molecule or present in a high concentration then it too will bind to the receptor.  A recent paper published in Nature (474:87-91) looked for molecules that would bind to the mosquito carbon dioxide receptor thus confusing the mosquito and limiting its ability to find us.  The scientists recorded the activity of the carbon dioxide receptor neuron and found one compound which activated the receptor for an unusually long period of time.  Such strong long-term activation of the carbon dioxide receptor could disable the response olfactory receptor neuron to carbon dioxide and should limit the mosquitoes' ability to track the carbon dioxide odor.  This is in fact what the researchers found; mosquitoes were placed in a wind tunnel with carbon dioxide being released from an air cylinder.  Fewer of the mosquitoes that were treated with molecule that activated the carbon dioxide receptor were able to find the carbon dioxide source and those that did took longer.  We can't stop breathing so it's a relief by blocking the ability of mosquitoes to detect and track carbon dioxide we may be able to hide our distinctive long range scent.