Those pin-cushion looking creatures you want to avoid touching or stepping on are sea urchins. There are about 950 species living in all oceans and depth zones, from the intertidal to 16,000 feet deep. Sea urchins are echinoderms, related to sea stars and sea cucumbers. Although that might not seem immediately obvious, sea urchins have five-part symmetry (watch our video on the body plan of these animals: Five part symmetry)
Cephalopods (octopus, cuttlefish and squid) seem to be flourishing in our changing oceans. Their numbers are increasing worldwide according to a 2016 study. Is the increase in cephalopods a good or bad thing?
We know the oceans are warming. We have evidence that that’s a bad thing. What is of additional concern is the effect of warming temperatures on natural ocean food webs. More cephalopods means more voracious predators eating more prey. All this ‘more’ may be a serious problem.
Albatrosses are amazing sea birds that spend over 80% of their lives at sea, visiting land only for breeding. An albatross can live up to 60 years and in that time it would have travelled millions of miles. To fuel their large size – they are the largest flying birds – albatrosses feed mainly on squid but also on fish eggs and crustaceans.
Many of the 22 species of Albatrosses are threatened with extinction. The greatest threat is commercial fishing: albatrosses get hooked when they dive to steal bites from a fishing boat’s baited hooks.
Believe it or not, millions of tiny delicate coral animals create the enormous coral reefs that can even be seen from outer space. The coral polyps (cnidarians related to anemones and jellies) live in a colony. Together they build a mineral skeleton from calcium carbonate, which creates a complicated reef structure with a myriad of shapes and sizes.
Coral structures provide endless habitats for other animals to live. It’s impossible to talk about corals without talking about the entire reef ecosystem. Coral reefs are the most diverse of any marine ecosystem, often referred to as the rainforests of the sea. A quarter of all marine species depend on coral reefs for food or shelter, or both.
Crustaceans begin life as an egg and then go through a series of larval stages, molting several times, before reaching adulthood. The first larval stage for crabs, lobsters, shrimp, barnacles, copepods, and some other crustaceans is called a nauplius. The nauplii of different species all look alike so they are hard to tell apart. These larvae live in the water column as part of the zooplankton.
They’re stealthy little creatures in that they blend in with many zooplankton. Because of this, predators have a hard time seeing them.
Imagine the oceans 530 million years ago, during the Cambrian Explosion, filled with creatures alien to us today. Anomalocaris (ah-NOM-ah-LAH-kariss), from the Greek meaning “unusual shrimp”, was a major predator of those ancient seas. Fossils from the Cambrian in the Burgess Shale in Canada, and formations in China, Greenland, Australia, and Utah show that this large, ancient shrimp was widespread during this period.
The “unusual shrimp”, which grew up to a six feet long 6’, is the largest animal among the Burgess Shale fossils. Scientific studies of fossil body parts and entire specimens have helped scientists understand Anomalocaris’ mode of moving and its predatory behavior.
They aren't fast or flashy-- but, boy oh boy-- do they ever pack a powerful punch for healthy intertidal habitats.
Their grazing “farms," where the limpets consume large patches of microalgae using their rasping radulas, generates more and more microalgae. In the process, they make space for other intertidal life including barnacles, tiny snails, and red and green algae.
The Illuminating World of the Ctenophore
Ctenophore is a small and absolutely beautiful creature. Known as comb jellies, they use eight longitudinal rows of cilia for locomotion. When the cilia beat, light is scattered, producing a rainbow of colors.
The beating combs act like a prism, breaking the light into its color components. Some species of comb jellies (like so many animals in the deep sea) make their own light, called bioluminescence.
Slipper snails live in the intertidal where they attach to a rock or often the shell of another snail. Are these snails male or female, or first one then the other? The answer is yes to all those questions. Slipper snails start life as males and change to female. This strategy is called sequential hermaphroditism. These snails change sex when they reach a certain size, depending on the sexes of the other slipper snails around.
Just like us, larvaceans are chordates. These small tadpole-like animals live at midwater depths of the world’s oceans. All species construct complicated, mucus structures, called ‘houses’ where the animal lives. To feed, the larvacean beats its tail, pumping seawater through its house. The sticky filter structure has two parts: the outer filter traps coarse particles; the inner traps fine ones. When the house becomes clogged, the animal discards it and it sinks to the bottom. In Monterey Bay, there are giant larvaceans that create large houses that can exceed one meter (three feet!) in its greatest dimension.