User:Maya.rosette

Purple Sea Urchins: Strongylocentrotus purpuratus The Purple Sea Urchin comes from the family Strongylocentrotidae and can be best described as a deep purple species that is round with spins that surround its outer shell, named the “test”. These spines serve to defend them from predators. Their predators consists of sea stars, otters, and humans who have found these urchins to be a delicacy. You can tell the age of a Purple Sea Urchin by looking at their color. If it has a greener hue then the urchin is not fully developed, but if it has a vivid purple color, then you can assume it is fully grown. A fun fact about this urchin: when a shadow goes over if its spikes point towards it.

Purple Sea Urchin

Purple Ochre Sea Star

Giant Green Sea Anemone

Ochre Star: Pisaster ochraceus otherwise known as the Ochre Star is a starfish that ranges between purple, orange, and reddish brown. They have five arms known as rays that surround their central disk. These creatures prefer cooler waters and use their tube feet in order to move around. Their mouth is positioned on the bottom and the starfish can grow from 15cm-35cm. Their predators are otters and gulls. These starfish can survive up to eight hours out of water. Something cool about this species is its ability to regenerate an arm after losing it, similar to a lizard after losing its tail.

Giant Green Anemones: When this Anemone experiences larger sums of light it achieves an even brighter green, but the contrary reduces its growth and can turn it to an almost white color. It can get up to 30cm tall and 17cm wide. Something interesting about this species is how much it has contributed to Medical research, even contributing as a vertebrate heart stimulator. Also, it can live up to hundreds of years old.

Acorn Barnacle

Acorn Barnacles: Balanus glandula

These invertebrates are filter feeders that live within the intertidal zone of tide pools. They start as planktonic larvae and eventually stick themselves head first to a hard surface, like a rock, wharf, or whale. Acorn barnacles can’t move from place to place. Unable to hunt or chase down prey, Acorn barnacles use their feather-like feet (called cirri) to filter plankton out of the nutrient rich seawater of the Pacific Coast. While the tide is high, this cirri comes out and they feed. Once it recedes, the opening closes off completely and traps water inside. This is a tactic used to conserve moisture during the time spent above water. These barnacles are actually hermaphrodites, meaning they have both male and female sex organs. Since they can’t move from the place they're stuck, their reproduction cycle is really interesting. Acorn Barnacles have really long penises (in comparison to their body length) to complete reproduction. Since they are stuck to one space, Barnacles have to mate with the other barnacles right next to them.

Sea Lettuce

Sea Lettuce: Ulva lactuca

Sea Lettuce is a type of photosynthetic algae that can be spotted by its (typically) bright green color and paper thin qualities. With no stalk or stem, the Sea Lettuce directly attaches itself to rocks or other organisms though it's holdfast. The holdfast is like the root system of this algae and helps to anchor it to the rocks, preventing it from getting washed out to sea. Located in the upper tidal zone, this lettuce is good at dealing with the varying tides. When low tide occurs, the algae dries up and turns hard. But as soon as the tide comes in again, the Sea Lettuce re-hydrates and continues to live healthily. Sea lettuce is typically found in the upper intertidal zone of tide pools, but can also be found in a number of marshes, bays, and open water. This is mostly due to its resilient nature. Sea lettuce is really good at thriving in areas other organisms may not be. In polluted areas, like areas with fertilizer runoff, Sea Lettuce thrives and grows strong. That's why this species is a good indicator species of something off. If we see larger amounts of this algae, we could inquire about the potential pollution levels there.

Opalescent Nudibranch

Sea Otter

Opalescent Nudibranch: Hermissenda crassicornis

The Opalescent nudibranch is a sea slug typically found in the tidepools along California’s coast. They are distinctly recognizable by the cerata on their backs and their bright colors. Their cerata are the tentacle-like things attached to their backs that have a surprisingly important role in their survival. The opalescent nudibranch likes to eat a variety of different things, like anemones, hydroids, tunicates, and even sometimes jelly polyps if available. The common denominator in this species prey is nematocysts, or stinging cells. The nudibranch can absorb the unused stinging cells of their prey in their cerata and turn it into protection against predators. This species only lives up to a year before its lifetime comes to an end. For this reason, the sea slugs don’t spend time finding and reproducing with one mate. They also don’t participate in typical broadcast reproduction, where egg and sperm packets are released in abundance and come into contact by chance. Nudibranchs are hermaphrodites, and leave their egg packets on blades of eelgrass or algae for other nudibranchs to come and fertilize. Then their life-cycle begins anew.

How these organisms coexist with each other:

Whether it’s transferring energy through consumption or competing for food, all of these organisms, and many that weren’t listed, interact with one another to create a rich and diverse ecosystem. Sea lettuce is a big part of this, as it is the main food source for sea urchins, and a big component in water quality. Sea lettuce has the ability to produce oxygen and regulate water quality by absorbing extra nutrients. It also creates good places for small invertebrates to hide and call home, adding to its significance. Sea stars and sea snails prey on Acorn Mussels, while Sea Stars and crabs are the nudibranchs main predators. Additionally, some organisms not directly in the tide pool contribute to the energy transfer of this ecosystem. For example, otters (which live in the open waters) eat sea urchins. This is an extremely important transaction, because it balances the food web. If the otters were taken out, then urchins would overpopulate and reduce the size of the Sea Lettuce. This would be harmful because of all the positive effects Sea Lettuce brings to the tide pool ecosystem. All of these species (in and out of the tidepool) work together to create a balanced food web that is productive and stable enough for the organisms in it to thrive and for us to observe its beauty.