Just under a million years ago, a major pattern in Earth’s climate suddenly changed. Instead of having an ice age about every 41,000 years, the cycle switched to about every 100,000 years – and the cold periods had even lower average temperatures than the previous ones. What caused the interval between ice ages to double?
The Marine Science Institute's monthly column, Science and the SeaTM, is an informative and entertaining article that explains many interesting features of the marine environment and the creatures that live there. Science and the SeaTM articles appear monthly in one of Texas' most widely read fishing magazines, Texas Saltwater Fishing, the Port Aransas South Jetty newspaper, the newsletter of the Texas Chapter of the American Shore & Beach Preservation Association , and the Heartland Of America online newspaper. Our article archive is available also on our website.
When a sea star (a.k.a. starfish) develops wasting syndrome, the disease hits hard and fast. Lesions appear on the star’s tough outer skin. Then the tissue around those white sores begins to decay. The sea stars “deflate” and lose control of their five limbs, which curl and twist and eventually begin disintegrating. The starfish gradually “melts” into nothing.
When the going gets tough, purple sea urchins appear to get tougher, or at least tough enough to possibly cope with climate change. Purple sea urchins are referred to as a “keystone” species because the ecosystem needs enough of them to feed marine mammals, fish, seabirds and other predators, but not so many that they overrun the place. Increasing carbon dioxide levels in the atmosphere may threaten that balance. As oceans absorb more carbon dioxide, the water becomes more acidic, which decreases calcium carbonate levels.
At 21 months, elephant pregnancies last more than twice as long as human pregnancies, and frilled sharks carry their embryos for 42 months – twice as long as elephants. But the deep-sea octopus has every animal on the planet beat when it comes to her unborn young. Researchers recently observed a deep-sea octopus mother brooding her eggs for 53 months – a whopping four and a half years.
A rapid ascent from deep water to the surface means a rapid drop in pressure. That can expand a fish’s swim bladder – the organ that helps a fish control its buoyancy – so much that it pushes other organs aside or even out a fish’s mouth. Scientists have worried that this “barotrauma” might permanently harm a fish, making it harder for deep water fish to survive if they are released. Fortunately, at least one popular sport fish can overcome this trauma.
Fields of dandelions are a familiar sight each spring, but another kind of dandelion is so rare that scientists are just beginning to learn more about it – the ocean dandelion.
Living in the deepest parts of the sea, the ocean dandelion is not a plant, yet it’s not exactly a single animal either. Rather, the ocean dandelion is a siphonophore, a unique type of organism composed of many smaller animals that together form a colony. The individual animals, known as zooids, are the “petals” of the ocean dandelion.
Survival of the fittest has been a law of nature since the beginning of life, but sometimes that struggle begins earlier than we might think. For baby sand tiger sharks, the fight literally begins even before they are born.
The female sand tiger has two wombs, but she does not have litters twice as large as other sharks. In fact, she only gives birth to two particularly strong, feisty pups. Newborn sand tiger sharks have keen eyesight and sharp teeth that have already tasted the blood of their siblings – or half siblings.
For almost any object in the sea, there’s a creature who will feed on it – even if it’s a whale skeleton or a shipwreck. Though not related to one another, boneworms and shipworms share the remarkable ability to locate their meals in the vast ocean. Boneworms consume the bones of mammals, fish, reptiles and other animals, while shipworms – actually a type of mollusk – use their tiny shells to burrow into the wood of wrecked ships, trees adrift, or other wooden structures in the sea. Despite having neither stomachs nor mouths, both boneworms and shipworms have symbiotic bacteria in their gut that release nutrients from the bones or wood which these “worms” absorb as food.
Perhaps you’ve heard of a full moon so bright you can read by its light. But what if you could also read by the light of ocean waves — at night, with no moonlight at all? If you’re in one of Puerto Rico’s famous “bioluminescent bays,” you might be able to. In these three bays, the water is full of tiny plankton called dinoflagellates which produce neon blue light called bioluminescence.
When we think of a pristine shoreline, we don’t usually picture man-made structures in the scene, but jetties and retaining walls are common sights along many waterways. Waves that continually crash against the shore release energy that can erode waterfront property. Bulkheads, retaining walls, and revetments are designed to protect shorelines by minimizing erosion. Over time, however, these structures may actually increase erosion by altering nature’s ability to replenish sensitive coastal areas.