Other Invertebrates (corals, sponges, worms, etc.)

Invertebrates are the animals in our world without a backbone. You know a lot of them. The insects and crustaceans have outer skeletons, while the mollusks and the worms don’t have much of a skeleton. Invertebrates make up more than 90% of the animals on earth and are part of the base of our food chain.

Corals, sponges, and worms are common words to our ears, but scientists would call them cnidarians, poriferans, and annelids. They each have their own phylum and each phylum is extremely diverse. One thing they all have in common is that they are ancient and simple biological organisms.

 

Aggregating anemones (Anthopleura elegantissima).

Corals, Anemones, & Jellies

Phylum Cnideria contains corals, anemones, and jellyfish (including Velella velella). Their name comes from the Greek word cnidos which means stinging nettles. Most animals in this phylum have a capability to sting prey with nematocyst cells which either sting or inject a toxin. Corals are in class Anthozoa and are sessile polyps that live in colonies which act as a single organism. The shapes of corals can be incredibly diverse, but they are all groups of tentacled creatures that live on a calcareous skeleton and share nutrients. Most corals are known for being very colorful, but they don’t actually have color. Many live symbiotically with algae that are extremely colorful. The algae provide carbohydrates to the corals, while the corals provide carbon dioxide for the algae. Sometimes, the coral may become stressed and it can eject the algae, which is known as “coral bleaching”. Coral is well known for the reefs it can form with its calciferous skeleton, but in central California, coral doesn’t form reefs. But, like a coral reef, corals of Point Reyes are extremely sensitive to change in salinity and temperature. Development along coastal areas can result in runoff, which changes the salinity of the water and can kill the corals.

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Sea Sponges

Phylum Porifera encompasses the sponges of the sea. The skeletons of sea sponges are well known because they are natural sponges and are often sold with spa products. There are different types and not all of them are useful as soft sponges because many varieties have skeletons that are hard and spiky. Sponges are extremely simple creatures and do not have blood or organs. They live by absorbing all of their gasses and nutrients from the water and returning wastes to the water by direct diffusion through cell walls. Most species require a solid rock to spend their life on, so it is not uncommon to see a bunch of corals growing together on an ideal spot which is referred to as a “sponge garden”. Sponges can be found in intertidal zones and in the deep sea.

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Long-billed dowitchers (Limnodromus scolopaceus) forage for worms at low tide. 

Worms

Phylum Annelida contains an extremely wide variety of segmented worms that live in an extremely wide variety of habitats. They can live in water, the ground, or in another animal’s body such as a snail. The segmented worms that live in the sea are referred to as polychaetes. Their name defines them as worms with “many bristles” because they have sensitive hairs on each segment of their body. Bristleworms, as they are sometimes known, make up a large portion of marine life. Predictably, these worms are a large food source for the carnivores of the sea and mudflats. Lugworms, sandworms, and clamworms are some popular types that feed birds, crustaceans, and fish. This certainly explains the abundance of animals foraging the mudflats during low tides.

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Red sponge nudibranch (Rostanga pulchra) on the arm of an ochre sea star (Pisaster ochraceus).

Here in Point Reyes...

Many of these invertebrates can be found at Point Reyes within intertidal habitats. Intertidal habitats exist on rocky shorelines that are only covered part of the time with water due to the tide. These pools are popular places for these animals to live because they receive a lot of sunlight which provides food for the things that intertidal creatures eat.

When exploring intertidal regions it is important to remember that these places are extremely sensitive. When the tide is low these animals are simply trying to “hold on” until the water comes back over them. Here are some simple rules for tidepool etiquette:

• Be careful walking. It is wet and slippery down there and a fall could mean injury to you and the animals. Also, many of the animals are not easy to see so look closely.
• Look more, touch less. Most of the animals will die if they are picked up and some may hurt if you touch them. Get down low and watch them at their level, this way you can see their interactions and learn a lot.
• Watch the waves. Waves are variable and dangerous if you aren’t watching them. Don’t be knocked over by a sneaker wave – keep your eyes on the ocean at all times.

Text by Kristen Truchinski

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Science & Research Project Summaries

From 2006 to 2018, Point Reyes National Seashore and Pacific Coast Science and Learning Center (PCSLC) staff and communication interns assisted scientists conducting research through the PCSLC and the San Francisco Bay Area Inventory & Monitoring Network to produce a series of Resource Project Summaries, one of which was, in part, about the impact of invasive marsh grasses on native estuarine worms and other invertebrates in Tomales Bay. These one- to eight-page summaries provide information about the questions that the researchers hoped to answer, details about the project and methods, and the results of the research projects in a way that is easy to understand.

• Comparing the Effects of Invasive and Native Marsh Grasses on Estuarine Invertebrates, by Elizabeth Brusati, University of California, Davis, March 2006 (151 KB PDF)

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Multimedia Presentations

From 2007 to 2012, Pacific Coast Science and Learning Center Science Communication Interns produced a series of podcasts exploring science from Bay Area national parks. One of these The Natural Laboratory multimedia products is focused on deep-water corals of the Cordell Bank. Listen to the podcast below. Visit our Multimedia Presentations: The Natural Laboratory Audio Podcasts page for additional podcasts.

 

• The Natural Laboratory Podcast: Deep-water corals of Cordell Bank

  
  

  A The Natural Laboratory podcast produced by the Pacific Coast Science and Learning Center in 2011 in which Cassandra Brooks interviews Lisa Etherington, Research Coordinator at the Cordell Bank National Marine Sanctuary, and Dan Howard, the sanctuary's Superintendent, about research on the deep-water corals of Cordell Bank and the impacts of ocean acidification on corals.

  Credit / Author:

  Cassandra Brooks / Pacific Coast Science and Learning Center

  Date created:

  01/05/2011

  Audio Transcript

  [Introduction]

  This is the Natural Laboratory, a podcast exploring science for Bay Area National Parks. I'm Cassandra Brooks.

  [music]

  Much of the ocean is a desert, dark depths devoid of life with muddy bottoms where animals scour for food and mates.

  But in the midst of these muddy bottoms, rocky banks rise from the continental shelf providing structure for life to grow and flourish. Cordell Bank, just 20 miles off the Point Reyes Seashore, is one such place. A world bursting with creatures beyond our wildest imaginations.

  [Interview with Lisa Etherington and Dan Howard]

  Lisa Etherington: The overwhelming colors and diversity of life that are associated with these corals and other animals on the bank is just...it's breathtaking. It's like nothing you've seen before.

  Dan Howard: Because of where the bank is situated and because of our local oceanography, it's a very very productive place, both on the bank and around the bank. So it just really is a...an oasis of life out there; it's just spectacular.

  Cassandra Brooks: That's Lisa Etherington, Research Coordinator at the Cordell Bank National Marine Sanctuary and Dan Howard, the sanctuary's Superintendent.

  A key component of this biological wonderland are deep-water corals. Unlike shallow water reefs, these corals thrive in dark water anywhere from just below the surface down to two thousand meters. All over the world, from the Arctic to Antarctica, researchers have found deep-water corals. And each new community they find supports an incredible assemblage of life.

  LE: I do know that some deep coral communities...uh...have been shown to have diversity levels of the associated animals with the...the corals to be similar to tropical reef systems. So, people think of these lush, shallow-water, warm-water coral ecosystems as being one of the most diverse places on earth, but, um, deep-water coral communities can rival that.

  They provide a 3-D structure, so a lot of organisms will use them as habitat, either for refuge from predation, areas of feeding, areas where, um, they will spawn, or nursery areas where young individuals can grow up.

  CB: And I wondered if, um, Cordell Bank wasn't designated a sanctuary because of the presence of corals?

  DH: I don't think, uh, when the sanctuary was designated in 1989 that many people other than the fishermen understood the deep coral communities. I doubt...I don't think anybody really understood it.

  CB: I know there's still a lot of things we don't know about deep-sea corals, but, in terms of what we do know, I understand they're really slow growing and pretty vulnerable.

  LE: Right. Right. I think it's been documented that some individuals will only grow one to two centimeters per year. So, it takes them a while to get to, um, you know, a substantial height. And some of these will, you know, be 10 to 15 meters high, you can have some really large colonies or individuals. And some form reef systems.

  CB: So how old are those that are 10 to 15 meters high?

  LE: I know they've been documented as over 1500 years old. So, one of the, uh, longest-lived organisms on the Earth.

  CB: As knowledge of deep-sea corals has grown, so has a desire to protect them. While acres of coral communities have been destroyed by trawl fishing, many countries, including the United States, have banned trawling over some seamounts or other rocky habitats where corals live. The hope is to protect the remaining deep-sea coral communities, though a new threat is on the horizon, one that is far harder to manage.

  LE: For deep-sea corals, one of the...the big concerns right now is the changing acidity of the ocean. So, as we put more, uh, carbon dioxide into the atmosphere, the ocean is taking up more carbon dioxide, which reduces the pH or increases the acidity of the ocean. And that causes, um, some potential detrimental impacts on corals which use calcium carbonate to build their skeletons. So, if we have a more acidic ocean environment, then it's harder for these animals to build their skeletons and also potentially could dissolve their skeletons in some cases.

  DH: You know, we have...we have so...so much to learn, but as a sanctuary, I, you know, we certainly, the one thing that we can do is...is try to protect these habitats and keep them in as, you know, as close to a natural state as we can so that they have the...the best chance possible to survive or, uh, be resilient in a changing environment.

  [Conclusion]

  With the Pacific Coast Science and Learning Center, I'm Cassandra Brooks.

  [music fades]

 

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