Archive for the ‘Marine Science’ Category

Marine Arthropods

Wednesday, September 17th, 2014

DesktopBoth crabs and crustaceans are of the phylum Arthropoda. In fact Arthropoda encompasses almost 75% of all animals’ on this earth.

By definition arthropods are invertebrates, meaning they lack a backbone. Arthropods are characterized by segmented bodies, jointed legs, and a hard exoskeleton. The land forms of arthropods include scorpions, spiders, and most insects while the marine forms are divided into three distinct groups – Horseshoe crabs, Sea Spiders, and Crustaceans.

Crustaceans include barnacles, shrimp, lobster, mole crabs, and true crabs. A few defining characteristic of crustaceans include their ability to molt (shed their shell), Metamorphoses (change body form during life stages), and regenerate (regrow lost limbs).

spinylobster2Blue crabs, stone crabs, and fiddler crabs are just a few examples of true crabs and are characterized by a short tail that is folded under the body.

Barnacles are small volcano-shaped animals that are sessile in adult form and therefore must utilize filter feeding. Mole crabs are small egg-shaped animals that inhabit the swash zone. They are an important link in the ocean food chain as numerous animals feed upon them. Shrimp and lobster appear to have a similar body form with the abdomen (tail) stretched out behind them.

horseHorseshoe crabs are one of the oldest known living species of animals on earth, it is believed that the lived in the ocean more than 600 million year ago.  Horseshoe crabs are so old they are in a class of their own. Though menacing in appearance they are actually rather docile.

Into the Unknown

Friday, April 5th, 2013

GALAXYWhether it be the far reaches of the starry galaxy or the inky blue of the ocean abyss for centuries the neighboring unknown has sparked fascination within every generation. Maybe it is because our bordering environments seem so close, yet so foreign.

Space and sea literally touch our world, yet we cannot survive within them. It is our desire to explore places so different from our own that it has driven the human population to push technology to its limits. There is a shroud of mystery surrounding both the oceans vast depths and the possibilities of deep space. Billions have been invested into expanding our knowledge and understanding of our unfamiliar neighbors, allowing us to fly a little farther and swim a little deeper.

MOON

It is said that we know more about the surface of the moon then we do about our own ocean. But how could this be? We have only visited the moon a handful of times while modern humans have depended on the ocean for the last 200,000 years.

Well, the moon resides on average 238,857 miles away from earth, and is locked in an endless orbit. Surface temperatures are extreme (-233 Celsius at night, and 123 Celsius during the day) resulting in a barren habitat seemingly uniform and void of life. The moon simply lacks the biological diversity that blankets the earth.

The ocean, on the other hand, encompasses some 139.4 million square miles, is almost 7 miles deep, with pressures reaching to 15,750 psi (over one thousand times the standard atmospheric pressure at sea level). It is one of the planets most diverse biomes containing an array of inhabitants. Some 250,000 (2010 Marine Census) known organisms call the sea home and according to most scientists it’s still teeming with undiscovered species.

therma vent

Anyone can explore the deep blue rather easily (well at least for the first 130 feet). A simple SCUBA diving certification will allow you to swim with the dolphins, sea turtles, and whales. Divers don a wetsuit, fins, and snorkel; they strap on a tank full of compressed mixed gasses and slowly descend into a fish eye view of the world.

Deep ocean exploration takes a little more advanced equipment. No more than an astronaut could survive the zero gravity and oxygen lacking environment of space without a special space suit could a human survive the crushing pressure of the lightless deep.

ALVIN

Therefore, scientific researchers often employ the help of remote and manned mini-submarines such as Alvin (DSV-2) for those hard to reach places. Alvin carries 3 people, has explored depths op to 14,800 feet, and is well known for investigating the infamous wreckage of the RMS Titanic in 1986.

Want to learn more about breathing underwater?

Tune in soon to discover more about the world of SCUBA diving!

Ocean of Light

Friday, February 1st, 2013

 

1firefly

Bioluminescence is defined as the production and emission of light by living organisms. It is often referred to as “cold light” as the reaction will produce a visual light but rarely generates any thermal radiation. The light is a form of natural energy released by chemical reactions within the organism. This ability to produce light without producing heat protects the organisms from literally burning u (ever touched a light bulb?!). This phenomenon is exhibited in marine vertebrates, invertebrates,fungi, microorganisms, and terrestrial animals. A terrestrial example that we are all probably familiar with is the firefly or lightening bug.

Fireflies contain specialized cell in their abdomen that contain a chemical called luciferin – this is also where an enzyme know as luciferase originates. Both of these are essential to light production.

The luciferin will coalesce with adenosine triphosphate (aka the ATP which is found in all cells) to form luciferyl adenylate and pyrophosphate (PPi) on the surface of the luciferase enzyme.

luciferin + ATP ————-> luciferyl adenylate + PPi

Oxygen than interacts with the luciferyl adenylate to produce oxyluciferin and adenosine monophosphate (AMP).

uciferyl adenylate + O2 ————-> oxyluciferin +AMP + light

Light results from the oxyluciferin and AMP being released from the enzyme’s exterior surface. Fireflies typically give off wavelengths of light between 510 and 670 nanometers which produces a soft yellow to reddish green color.

Bioluminescence is uncommon in terrestrial animals, conversely ninety percent of known deep-sea marine life bioluminesce. The majority of marine organisms that bioluminesce emit blue or green because those particular wavelengths transmit throughseawater more clearly than other colors.

1anglerBioluminescence has several functions depending on the species. Mimicry, mating, distraction, repulsion, communication, and illumination are the most common ways bioluminescence is utilized in the animal kingdom. The deep sea angler fish uses a glowing lure to attract prey, fireflies and ostracods (small crustaceans that resemble shrimp) depend on it to initiate mating, while some squid species can expel a cloud of bioluminescent material to confuse potential predators long enough to escape.

There are numerous and varied marine species that employ the use of bioluminescence to survive, but for most of us on dry land running across these glowing creatures of the deep in unlikely. Fortunately for those interested in experiencing an ocean alight (and aren’t necessarily willing dive into the deep) there is one tiny organism that is known for putting on a pretty grand display.

1biolumocean

Marine plankton known as dinoflagellates sometimes give off an eerie dull glow and often a flash of green light when they are disturbed. Dinoflagellates are commonly found in surface waters, but rarely in the high concentrations as displayed in Bahia Fosforescente, Puerto Rico where a single paddle stroke can set off an underwater fireworks show. Though scientists aren’t exactly sure why dinoflagellates glow, most suspect it has to do with predation and it iscertainly a sight to behold.

So remember, the next time you are walking along a peaceful beach at night and the entire ocean seems to be romantically aglow it all because of some slightly agitated microorganisms.

 

You can huff and puff but you can’t blow me down!

Wednesday, December 19th, 2012

Have you ever been to the beach on a windy day? If so, then you’ve had that raw sandblasted sensation once or twice after a visit to your closest coast. As sand whips down the waterline you may feel more like your traversing the Sahara Desert than a tourist vacationing on the seashore. This is actually a very important part of beach building. Swift winds relocate sand into the dune bed, essentially building up this protective zone.

The fact is beaches, and more specifically dunes, are in a constant state of change. A major energy convergence occurs at the beach-line as waves, wind, and earth abruptly meet.  Beaches are endlessly growing, shrinking, and shifting, depending on the location and time of year. Add in the occasional tropical storm, longshore current, and the daily tide and it’s a wonder we have them at all.

When left to their own devices beaches are naturally able to sustain themselves. You may have heard discussion on the negative aspects of beach erosion but, in fact, beaches are the product of erosion. Composed of eroded sediment, shells, and minerals they breakdown and rebuild continuously. Over millions of years beaches have naturally relocated thousands of miles from where they now stand. Coastlines have been changing and adjusting since this planets birth, only in the past few centuries when man-made structures became threatened has this normal migration become a “problem”.

Jetties, seawalls, and beach renourishment are all processes used to “keep the beach where it is” so that the luxurious condos, waterfront houses, and pricey resorts don’t fall into the sea. Unfortunately these measures are extremely expensive and only work short-term. These solid structures inhibit this natural cycles of sand movement. The coastline will always move, with or without manmade structural support. Building a house on barrier island is like building a house on an airport conveyer belt and then acting surprised when your house falls down.

Though wave energy is responsible for shaping most of the beach, dunes are more the product of wind and an essential part of regulating and maintaining a beaches structure. Dunes are held in place by highly adapted vegetation and the dune face is a very harsh environment. Extreme temperatures, strong winds, and salt spray make the dune a particularly tough place to survive for most plants. However there are a few species, such as the sea oat, that can bear the cruel climate. These plants are responsible for dune building because they trap windblown sand and their root systems provide stabilization near the surface.

Beaches and dune systems offer a large amount of protection for coastal communities by absorbing the energy of the ocean as it migrates to shore. However the effectiveness of this protection directly correlates to the areas ability to naturally reform and shift. Humans attempt to control these natural processes unsuccessfully and each year millions if not billions is spent repairing and rebuilding permanent structures along ocean’s edge ( i.e. Hurricane Sandy).

No matter what precautions, measures, or action plans me make anything built adjacent to the ocean will eventually be reclaimed by the water and the sand as sea level continues to rise. We can either learn from this historical movement, or find ourselves twisting in the sandy wind.

 

 

Oil + Corexit = Concentrated Chemical Cocktail

Wednesday, December 12th, 2012

Unsurprising news out of the Gulf of Mexico this month: the oil that spewed from the Deep Water Horizon well and the subsequently used clean-up dispersants apparently make for a toxic combination. Few will be astonished by this news, but what is startling is the synergistic toxicity of these two substances – the combination of oil and Corexit result in a substance 52 times more toxic.

Images of the BP Deep Water Horizon spill are permanently seared into our memories. An estimated 4.9 million barrels – enough to fill over 3 Olympic size swimming pools each day of the spill– plumed up from the ocean depths. Then there was the Corexit dispersant application – another estimated 1,000,000 gallons added to the mix. All these ingredients combined to create a toxic soup that was exceptionally hazardous to both marine life and human.

To test the synergistic effect, researchers from Georgia Institute of Technology and Universidad Autonoma de Aguascalientes mixed oil from the spill with Corexit (2 different types were used: Corexit 9527A and 9500.) They then used rotifers, an aquatic invertebrate found in both freshwater and marine systems, to test the toxicity. Not only did this chemical cocktail cause rotifer mortality, but as little as 2.6% of the mixture would result in a loss of 50% of rotifer egg hatching.

Rotifers are a type of microscopic zooplankton that comprise their own phylum Rotifera (Latin for wheel bearer – a reflection of the wheel-like organ used for movement and feeding.) Rotifers are frequently used as a marine “canary in the coal mine” as they have a quick response time. Successful rotifer hatching are vital for the entire aquatic environment. These small, vase-shaped animals are a primary food source. In the ocean they provide sustenance for copepods, juvenile fish, crabs, shrimp, and many more.

We knew that the oil engulfing the Gulf was toxic. We long suspected that the Corexit used to clean the mess, was toxic. But together the two chemicals pack at toxic punch that is 52-fold stronger than it counterparts. While rotifers are small, and therefore seemingly easy to dismiss, they are the bearers of some big news that has the potential to ripple through clean-up efforts around the world.

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