Invertebrates in kelp forest dwell in a variety of different spots due to their diversity as a phylum, but most invertebrate can be found at the base substrate of the kelp in the kelp forest. Many invertebrates can be found here either using the protection of the kelp forest to capture their prey (other invertebrates, plankton, etc.) or eating the giant kelp that is the distinct feature of the kelp forest. Invertebrates are not limited to the seafloor though, invertebrates such as squids (cnidarians) have the ability to swim through the water allowing them to prey on the plethora of organisms that live in the habitat of the kelp forest.

Porifera

Orange Puffball Sponge

Tethya aurantia

Habitat: southeastern Alaska to central Baja California, from low intertidal to 1,460 feet (440 m)

Species role: Sponges are a food source for species like nudibranchs, chitons, sea stars, turtles and some fishes.

Lifecycle: The sponge reproduces in 2 ways. The first way is the parent sponge budding, which is when the parent releases cells that can mature on their own into an individual sponge. The other way is by smoking which is when the male sponge releases thousands of sperm cells into the ocean in a thick cloud resembling smoke. The female then catches the sperm and is fertilized like with sexual reproduction involving meiosis. After fertilization the larva is released. The larva is free swimming and is able to swim for 2 days and then it needs to find a suitable place to settle. When it finds a site it is then able to cling and begin growing. A sponge grows according to its environment so no 2 sponges are alike.

Survival adaptation: Sponges can produce potent chemicals that defend against species that try to overgrow, poison, infect or eat the sponge. The chemicals don’t harm the sponge because the sponge has the same properties of anti-bacterial and anti-cancerous drugs that don’t kell healthy cells.

Orb Sponges

Leucandra heathi

Cnidarian

Starburst Anemone

Anthopleura sola

Habitat: Starburst anemone is found in the Pacific Ocean, along the west coast of North America from Alaska to Baja California.

Species role: Starburst anemone are unusual because they play the role of both producer and consumer in intertidal communities, and it is believed that they contribute at the same rate to primary productivity as do some intertidal algae.

Lifecycle: Starburst anemone can reproduce both sexually and asexually, although most reproduce asexually. In sexually reproduction, gametes are released during the summer and fall into the surrounding water. A planula larva forms after fertilization. The free-swimming larva undergoes further development and then settles down to form a new sessile anemone. Large numbers of gametes are produced, although very few larvae will survive to adulthood due to predation and the inability to find suitable habitat. Asexual reproduction is a form of growth and seems to occur when an individual has found a suitable habitat. Anthopleura sola reproduces asexually by longitudinal fission. During longitudinal fission, the anemone divides into half forming two smaller anemones. Asexually reproduction takes place mainly from September to March and may be triggered by a reduction in food supply. Asexual reproduction results in genetically identical clones that have the same color patterns and sex.

Species adaptation: Starburst anemones live in colonies. Individuals at the edge of the colony are smaller, have larger fighting tentacles (acrorhagi), and reproduce asexually more frequently. This division of labor allows individuals in the center to expend more energy on sexual reproduction, as it is unlikely that they will encounter individuals that are genetically different. Individuals on the edges of aggregations expend their energy on developing large acrorhagi to fight the individuals of adjacent clones.

Brooding Anemone

Epiactis prolifera

Habitat: They are usually found in the subtidal zone (zero tidal zone), especially on intertidal rock benches or surge channels, and in rocky areas with wave action, often in areas with crustose coralline algae. Brooding anemones are also regularly found on the leaves of eelgrass. Red or pinkish red specimens are sometimes found on rocky shores, but rare on eelgrass. They are rarely exposed to the air, not being able to tolerate exposure to the air and sun.

Species role: The brooding anemone is a consumer and eats shrimp, and small fish. It also creates a mutualistic relationship with crabs where they hitch a ride with crab and protect it.

Lifecycle: The lifecycle of a brooding anemone is like that of any other anemone. It can reproduce both asexually and sexually. To find more detail about how an anemone reproduces look at the lifecycle of a starburst anemone.

Survival Adaptation: Their stalk and tentacles are bristling with an arsenal of stinging cells, or nematocysts. The double walled microscopic stinging cells contain a hollow thread with a minute harpoon-like barb at the end. When the cell is stimulated either physically or chemically, it explodes and fires the barb and attaches the thread with incredible force into the potential predator or prey and simultaneously injects a potent poison. Usually hundreds and thousands of these stinging cells are activated at once, which can paralyze prey or deter most predators. After being immobilized, the prey which may include shrimps, crabs, jellyfish or small fish is manoeuvred by tentacles towards the mouth where it is consumed whole.

Echinodermata

Eleven-armed Sea star

Coscinasterias calamaria

Phylum: Echinodermata Class: Asteroidea Order: Forcipulatida Family: Asteriidae

Habitat: Kelp forests provide a good habitat for Coscinasterias calamaria because Kelp Forests draw a large amount of other organisms (to prey on) as well as providing shelter from dangerous open ocean predators. These sea stars can be found in the low tide zones (up to 150m) of the Kelp Forest, crawling along the ocean floor (using rocks and other objects as shelter).

Lifecycle: Coscinasterias calamaria uses meiosis (AKA self-division) to reproduce, thus, these sea stars constantly have dettached arms that are regrowing to full length.

Species adaptation: Coscinasterias calamaria much like other sea stars use meiosis to reproduce and have the ability to amputate and grow back arms of their five-sided body. Unique to Coscinasterias calamaria though is its evolutionary development of up to 14 arms on its body. This adaptation is very successful because with many arms, the sea star can catch much more prey as well as having more sensory tentacles to detect prey. Coscinasterias calamaria is the one of the best examples of a sea star because it shows sea stars’ amazing ability to regenerate arms and catch prey.

Purple sea urchin

Strongylocentrotus purpuratus

https://www.youtube.com/watch?v=ak2xqH5h0YY

This video talks about the reproduction of sea urchins as well as their role in the kelp forest.

Species role: Sea urchins consume kelp which is detrimental to the kelp forest because of the over population of sea urchins

Mollusca

Nudibranch

Ceratosoma brevicaudatum

Class: Gastropoda Order: Nudibranchia Family: Chromodorididae

Habitat: Nudibranch are bottom dwelling gastropods that live on the ocean floor crawling and sometimes swimming to catch their prey. Kelp forests provide a habitat for the Nudibranch because they are rich in organisms that the nudibranch can feed on. These organisms include (but are not limited to): sponges, tunicates, cnidarians, ascidia, bryozoans, some algae, and sometimes other Nudibranchs. Kelp Forests naturally attract Nudibranchs because Kelp Forests create an ecosystem that foster organism diversity on many different levels. Nudibranchs are common across most oceans of the world, but prefer warmer tropical waters.

Species role: Ceratosoma brevicaudatum and other Nudibranchs are carnivores that roam the ocean floor for food. Nudibranchs are gastropods in the larger phyllum of Molluska, thus, they are predatory species while also being the prey of various other animals (invertebrates and vertebrates) such as spider crabs, turtles, and humans.

Lifecycle: Nudibranchs are hermaphroditic (having both male and female reproductive organs), thus, Nudibranchs only need one other partner (and don’t have to worry about the sex of the other) to reproduce. In the mating process nudibranchs both release sperm and eventually lay up to 1 million eggs each. These eggs take as long as 5-50 days to hatch and become Veligers (larvae with shells). Nudibranchs have been known to live for anywhere between a couple week and about 3 years.

Species adaptation: Aside from Ceratosoma brevicaudatum, there are over 3000 different species of Nudibranch alive today. One obvious adaption is their lack of a shell (through evolutionary processes), and this has allowed them to be more mobile and quick while also taking on more danger because they have to hard protective covering. To make up for this, Nudibranchs have adapted complex defenses including the ability to take the dyes from the food they eat and display it on their body as either camouflaged or an aggressively violent color scheme (to scare predators). As well as being able to ingest colored dyes, some Nudibranchs have developed the ability to ingest poisonous prey (including anemones) and use the poison from those organisms as their own defense against predators.

Moss Crab

Loxorhynchus crispatus

Habitat: Moss crabs are marine crustaceans that are most commonly found in the middle and deeper reef regions of kelp forests. They may also be found in rocky areas or on underwater structures in the epipelagic zone, up to 183 m deep. This species prefers habitat with plants or other cover material, which provides protection from open water predators.

Species role: Moss crabs are generalist omnivores and scavengers, feeding on many kinds of invertebrates, both living and dead worms, molluscs, and other crabs, algae, and giant kelp. They are also a food source for a variety of fishes, marine mammals (more rarely), and invertebrates.

Lifecycle: Moss crab eggs are attached to setae on their mother's pleopods; eggs may be as large as 0.55 mm in diameter. As embryos grow, they consume egg yolk and, as eggs near hatching, they turn gray in color. These crabs begin life as protozoea larvae. After approximately 30 days, they develop into planktonic zoeae, swimming with limb-like cephalothorax structures, which will develop into the antennae and mandibles. A zoea completes two additional developmental stages, lasting about 18 days, before metamorphosing into a megalops, resembling a small adult. After additional molts, it becomes a juvenile crab, with an average carapace width of 1.5 mm, and eventually develops into a sexually mature adult.

Survival adaptation: Moss crabs are known for decorating their shells by attaching other organisms such as algae, sponges, and bryozoans to their shells, helping them to blend in with their environments. They do not use an adhesive material to attach decorations, instead using their hooked setae to secure materials and other organisms.

References

Elder, A. 2001. "Anthopleura sola" (On-line), Animal Diversity Web. Accessed March 04, 2017 at http://animaldiversity.org/accounts/Anthopleura_sola/.

“Eleven-armed Sea Star.” Australian Museum. Januaru 5, 2010.

https://australianmuseum.net.au/eleven-armed-sea-star.

Conway, Jenny. “Diving with Nudibranchs It's only a slug, right?” Dive the World. http://www.dive-the-world.com/creatures-nudibranchs.php.

“Coscinasterias calamaria.” Wiki spaces. 2017. https://phylumofechinoderms.wikispaces.com/Coscinasterias+calamaria.

“Nudibranchs.” National Geographic. 2015. http://www.nationalgeographic.com/animals/invertebrates/group/nudibranchs/.

“Orange Puffball Sponge.” Monterey Bay Aquarium. 2017. https://www.montereybayaquarium.org/animal-guide/invertebrates/orange-puffball-sponge.

“Porifera Lifecycle.” Animal Biology Spring. 2010. https://sites.google.com/site/animalbiologyspring2010/porifera/life-cycle.

“THE RACE ROCKS TAXONOMY.” racerocks.com. Pearson College. http://www.racerocks.com/racerock/eco/taxalab/ensy02/sangeetaa.htm.

Ruigómez, Victoria Bengoa. “Nudibranchs: Beautiful but Dangerous Marine Creatures.” Advanced Aquarist. November 2007. http://www.advancedaquarist.com/2007/11/aafeature2.

Standen, Amy. “Sea Urchins Pull Themselves Inside Out to be Reborn.” YouTube video, 3:22, posted by DeepLook. August 23, 2016. https://www.youtube.com/watch?v=ak2xqH5h0YY.

Sanders, A. 2013. "Loxorhynchus crispatus" (On-line), Animal Diversity Web. Accessed March 04, 2017 at http://animaldiversity.org/accounts/Loxorhynchus_crispatus/.