Keystone Species - Sea Otters

We talked about keystone species. Keystone species are important members of the food web because they help maintain biodiversity and keep everything in balance. An example is a sea otter. Sea otters eat sea urchins and keep their population in check. Trey loves sea otters - even though I keep telling him they are vicious and have scary teeth!

When the sea otters are removed (like when they used to be hunted for their fur), the sea urchin populations go crazy, eat all the kelp (as in many many 300 foot tall plants), and the loss of kelp leads to a drop in biodiversity because there is less food and habitat for the many other species that like to live in and on and among the kelp.

Look at these before and after food webs when the sea otter is removed from the kelp forest. (from this website)

Parrotfish

Parrotfish are part of the nekton because they swim. They are omnivores because they eat coral (animal) and algae (plants). This fish is a male because it is more colorful than its female counterpart. Some may consider this warning coloration because it will chomp on things that try to mess with it. An odd part of their niche is that the coral they digest is where most of the white sand in tropical locations comes from.

Mutualism, Commensalism, and Parasitism

We started class with a BrainPop on symbiosis and then went right into notes covering the same material. We did take a lot of notes today, but the subject matter is interesting and students were asking a lot of questions.

Mutualism is the relationship that is best understood because both organisms benefit - although the advantages are not often clear to us. Pictured to the left are an alligator and plover, eel and cleaner shrimp, and zebra and finch - all of these are cleaning relationships. The smaller organism eats parasites and gets a meal and the larger organisms will not eat it as well as get the benefit of being cleaner (less infection and disease). The bottom right picture is a blind bulldozer shrimp and a goby fish. They share a dwelling that the shrimp builds, and the fish lets the shrimp know when trouble is coming. (Photos from this cool blog)

Parasitism involves things that give us the heebie jeebies. These parasites take advantage of their host, usually feeding on the host, and benefit. The host gets no benefits and over the long term is harmed.

Commensalism is when one organism benefits and the other is unaffected. So one gets all these advantages from the other... but the other doesn't get a benefit from it and isn't harmed by it.

Here are some other fun photos of oceanic relationships. Identify some and turn them in for extra credit!

Camo and coloration

We discussed predator prey adaptations - specifically coloration. The first topic is camouflage. Flounder (like the ones pictured) have passive camouflage. Their bodies are patterned and it allows them to blend in with the background. Can you spot the flounder in these photos?

Active camouflage is when an organism can actually change the color of its skin to match a background or flash colors to confuse predators and prey. Watch the Kings of Camoflage video about cuttlefish in the sidebar for more information.

The photo above is from this cool website blog that archives photos of all kinds of animals that are camouflaged.

We also talked about other types of coloration like mimicry, flash, warning coloration, advertising, and sexual dimorphism. Students finished the day by reviewing coloration and coloring their own fishes.

Lifestyles and Feeding

Today in class we discussed different lifestyles. Organisms can be plankton and spend their lives floating and drifting. Nekton means they can swim. Benthic organisms, or organisms that spend their time on the bottom can be attached, can crawl, walk, and some swim - but if they swim they swim along the bottom and spend most of their time resting on the bottom.

Next we discussed eating. Producers don't eat - they can make their own food. Producers starts with P and so does Plants and PhytoPlankton.

Herbivores eat plants, Carnivores eat meat, and Planktivores eat plankton. Students worked on a worksheet sorting organisms into their varying lifestyles and eating preferences to finish class.

We technically finished class with a little Blue Planet - watching orcas practically beach themselves in an attempt (a successful attempt to eat baby seal lions on the beach). :)

Sand & Underwater Vehicles

Today we discussed sand and where it comes from, what its made of, what colors it can be, an how shape and size affect the texture. In Hawaii there are black, red, and green sand beaches that have been deposited from the weathering and erosion of volcanic rocks. In the Caribbean, you can visit white and pink sand beaches from the weathering and erosion of sand and coral.

Students used scopes and made observations of sand samples from Hawaii, Grand Cayman, Normandy France, Lake Anna, Lake Superior, California, and Virginia Beach. Adrienne's mom brought us some sand from her recent trip to the Carribean - THANKS! Students determined what the sand was made of, where it came from, how old it was, if it was on an active beach, a windy beach - all kinds of information can be collected from a simple sample of sand!


The rest of class was spent working independently on the seafloor features surrounding the United States and reading and answering questions about underwater vehicles. Submarines are larger than submersibles and carry more people and can go longer distances. ROVs and AUVs are robots like remote-controlled cars, but go underwater. ROV's have a tether (cord) connecting them to power and AUVs do not.

Plastic in the Ocean - Seafloor Features

Almost ninety percent of them are not recycled and quite a lot of them end up blowing and floating around the environment where they look gross but also pose a hazard to wildlife. Most students do not think about where their garbage ends up. If you'd like to see the presentation - click here. For more information about plastics in the ocean - check out this info from the Ocean Conservancy.

Today in notes we covered sea floor features. We discussed the definitions and identified them on maps and then answered some questions. Test yourself - can you identify the features to the right?