In the southern California bight, the Channel Islands archipelago sits in warm subtropical waters brought north along the coast from Mexico to the islands. Toward the east, Santa Catalina Island supports many different fishes living in these warm waters. On a recent thesis sampling trip, frenzied fish behavior was observed. Similar to people gathering at a popular eatery, small orange cigar shaped fish called Senorita, and speckled kelp bass, schooled near disturbances created by divers. You may see the small grayish crab in the photo just underneath the fish's mouth (see below). These fish would say that algae mats provide a home for many tasty invertebrates!
In early June, I went camping with my family in Southern California at El Moro Campground, a part of Crystal Cove State Park. While there one day, I was excited to learn that there was going to be a -1.8 foot tide at 6 am. So, the next morning, my mom and I woke up bright and early and made our way to Corona del Mar Beach.
Corona del Mar Beach at a -1.8 foot tide early one June morning. Photo by Catherine Drake.
The last time I visited Corona del Mar Beach, which is a relatively unknown tide-pooling location, was about two years ago. I noticed that in this two-year span, this particular rocky intertidal ecosystem changed drastically: the mussel beds expanded, less surfgrass canopied the habitat, and both crustose coralline and red algae filled the void. Ochre sea stars, once abundant on the northern part of the beach, are now flourishing about 100 yards south for better access to the mussel beds.
A flourishing mussel bed (Mytilus sp.) in the rocky intertidal. Photo by Catherine Drake.A shore crab (Pachygrapsus sp.) eats a limpet as it moves through the intertidal. Photo by Catherine Drake.A uniquely neon green anemone (Anthopleura sp.). Photo by Catherine Drake.
This was by far my favorite tide-pooling experience. I spotted organisms I had never seen in the rocky intertidal before, such as a Hopkin's rose nudibranch (Okenia rosacea). I also was witness to feeding behaviors I had not previously seen, such as a crab eating a limpet as it traversed the rocks, and an egret moving within a tide pool with such delicacy to find its prey, an oblivious fish.
An egret prevails in its hunt for breakfast. Photo by Catherine Drake.
Massive dock from Japan that washed ashore in Oregon. Photo by Oregon State Parks and Recreation Department.
At 66 feet long, 19 feet wide, and 7 feet tall, the massive dock that washed ashore on Oregon's Agate Beach is larger then anything I have ever found on the beach. This dock is one of the first large pieces of debris to make it across the Pacific ocean from Japan after the earthquake and tsunami in March of 2011. According to news reports, the debris came from the northern Japanese city of Misawa, arrived almost nine months earlier than officials originally thought.
Hitchhikers from Japan made it alive and well despite the almost 5000 mile journey. Photo by Oregon State Parks and Recreation Department
But this dock did not arrive alone. Many organisms hitched a ride on this dock for the almost 5,000 mile journey across the ocean. Floating docks and other harbor structures provide habitat for many invertebrates and algae. The movement of these organisms to the Pacific Northwest, many of which are not native to this coast, may pose a threat to the diversity of native species that live there. To prevent these possible problems, scientists and managers took samples of organisms that arrived on the dock then scrapped the remaining organisms, buried them deep in the sand up the beach, and then used blow torches to dock to remove all remnants and reproductive material of the organisms.
With continued global expansion of humankind and climate change, how will native communities be affected by introduced species? Recent state surveys identified at least 312 non-native species in California coastal waters, many of which are known to have strong negative impacts on shipping, recreational and commercial fishing, and native habitats and local species (CDFG, 2008). Factors regulating the success of non-indigenous species are of interest to scientists and managers.
A view of boats that use Monterey Harbor and may unknowingly transport invertebrates from other marinas and harbors.
Artificial habitats like floating docks and pontoons act as ground zero for newly arrived non-indigenous species. These species arrive though many mechanisms, such as ballast water and fouling on the bottom of boats; we heard all about ballast water from fellow MLML student Catherine Drake, The Ballast Water Balancing Act. Species that settle in marinas and harbors can than travel along the open coast and into estuaries, where they may outcompete native species for resources and become dominant on human structures such as water pipes, sewer grates, and aquaculture cages.
Dockside view of my thesis installation with helpers Hannah and Heather. Photo by Scott Gabara
Under the floating docks of Monterey Harbor animals are battling for space. For my thesis at MLML, I am studying the role of native invertebrate species on invasion success. I will look at the sessile invertebrates like tunicates (Phylum Chordata), mussels (Phylum Mullusca), bryozoans (Phylum Byrozoa), hydrozoans (Phylum Cnidaria), feather-duster worms (Phlyum Annelida) and anemones (Phylum Cnidaria). By making experimental treatments that vary the number of species, the amount of native verse non-native species, and the amount of open space in artificial communities hopefully I can untangle part of the story about how non-native species become established.
Take a look under the dock as the battle is under way and stay tuned for the winner!
Diver, Heather Hawk helps steady treatment plots of native and non-native sessile invertebrates Photo by Scott Gabara
Every time you find yourself walking along the beautiful Elkhorn Slough, do you admire all you see? I guess we would have a conversation about the birds, crabs, even the occasional fish you may have seen. What about the snails? Oh yes, what about them? They are actually intermediate hosts to unseen residents of the slough, the trematode Cercaria batillariae. Trematodes are also known as flukes, and even though they may have a bad rap in some circles, they merit respect. Their life cycles involve sometimes one or more hosts, specialized to supplying different needs of the trematode. Some trematodes are even known to take over a snail body and mind modifying its behavior in order to get to its next host! Check this out this video on the trematode species Leucochloridium making “SNAIL ZOMBIES”:
Snail Zombies? You may think primitive, but in fact trematodes have recently been shown to show the ability to form caste systems just like your everyday ant or bee. According to Hechinger et al this is the first time this has been shown in flatworms.
So, next time we take a stroll around the slough - let’s chat about the unseen, shall we?
Docked in the Carquinez Strait, an offshoot of the San Pablo Bay in the city of Vallejo, is the TS Golden Bear. It is a training ship for the California Maritime Academy, which—like MLML—is a campus of the California State University. The Biological Oceanography lab at MLML utilizes the ship for ballast water research. As ships traverse the globe, they pick up ballast water from one area and release it back into the ocean once they reach their destination. Ships uptake seawater into their ballast tanks to optimize balance and streamlining when traveling a great distance. During this process, potentially invasive planktonic organisms are brought into the tanks and transported by being held in the ballast tank during travels. As these organisms are released back into the ocean, they are now introduced into a new environment.
The TS Golden Bear, which houses the laboratory and is the source of ballast water used in the research conducted by the MLML Biological Oceanography lab.Ships take in seawater and store it in ballast tanks in order to remain balanced as they glide through the oceans. Then, they discharge the ballast water as they enter a port or harbor.
This can pose a problem, as some plankton can become invasive, meaning that they can outcompete native organisms in a habitat. According to Ruiz, et al., shipping is considered the largest transfer mechanism for coastal invasions. As a result, regulations developed by IMO (International Maritime Organization) are implemented to reduce invasive plankton. One of their requirements forces ships to reduce the number of live zooplankton to 10 live zooplankters per 1000 liters after the water has been treated with a kill-factor (toxic reagents, oxygen reduction, UV light, heat, etc). “Though the challenge of coming up with an effective but environmentally safe kill factor is still up and coming, so are the methods to determining the quality of the treatment system,” says Julie Kuo, a student in the Biological Oceanography Lab. Consequently, this has enhanced the collaboration between engineers, and scientists to construct standard operating procedures to determine the quality of a treatment system based on IMO regulations.
Copepods, tintinnids, rotifers, and cladocera are all zooplankton that can be found in ballast water.
Enter Dr. Welshmeyer and the Biological Oceanography lab: the purpose of their project is to count the number of live zooplankton alive before and after the treatment. This process is used to determine whether or not the treatment tested on the Golden Bear is successful at meeting the IMO regulations. As we boarded the ship, we carried microscopes and coffee down through the ship to a room that was designated as our lab. In the 8 by 15 foot room, we setup our microscopes and began counting zooplankton. That particular day, we were counting pre-treated water, which was full of zooplankton swimming around; this included tintinnids, copepods, rotifers, and nauplii. After our counts of the live and dead zooplankton, we extrapolated that there were anywhere from 100,000 to 200,000 live organisms per cubic meter; up to 60% were alive in an untreated sample that was concentrated from one cubic meter of water from the Carquinez Strait. So, treatment systems have to be incredibly affective in order to kill all but ten zooplankton in ballast water!
Julie Kuo, a graduate student in the Biological Oceanography lab at MLML, counts the number of zooplankton in a sample of pre-treated ballast water.
One great aspect of being a graduate student in the invertebrate zoology lab at MLML is that we get the chance to take care of various invertebrates in our aquarium room. Currently, we have anemones, mussels, crabs, and sea stars living in our tanks. One of the sea stars, called a sunflower star (Pycnopodia helianthoides), is special and gets its own tank for a number of reasons. Firstly, the sunflower star is the largest sea star in the world, and can grow up to one meter in length. Sunflower stars generally have 15 to 24 arms, which is more arms than any other species. They are also the heaviest sea star and can weigh up to 5 kilograms, which is about 11 pounds. So we like to give our big star plenty of room to roam around - sunflower stars are fast and can move up to one meter per minute!
Many sunflower stars (Pycnopodia helianthoides) living in a kelp forest. Sunflower stars are the largest sea star and can be many different colors.
Below is a video of our sunflower star, and you will be able to see various distinctive features. Along its arms are tube feet, which operate by hydraulic pressure and are part of the water vascular system that facilitates respiration, movement, and feeding. Sunflower stars generally have about 15,000 tube feet! In the center of the body, you can see a white spot, or madreporite, which is a water filter for the vascular system. The blue nodules on the sea star are called pedicellaria, which are pincers on the body wall and are used for protection; if you put your hand on them, it feels like Velcro!
Chilean and American students combine forces to process green algae samples for isotopic analysis.
The Moss Landing Marine Labs Global Kelp Systems class went to Chile and learned to process samples of algae and invertebrates to get carbon and nitrogen isotopes. These isotopes were collected to help scientists learn about the impact of creating a kelp farm where kelp would not have been otherwise. Algae and inverts have different isotope signals, so isotopes can help in tracking where nutrients go. What did this kelp crab have for dinner? Looks like algae from the kelp farm!
Different red algae samples for isotope analysis.
These inverts were collected in the kelp bed to track where kelp nutrients go.
Moss Landing diver holds a kelp crab that is eating the Giant Kelp being grown on the farm.
The Moss Landing Global Kelp Systems class was fortunate enough to dive in a kelp farm designed to grow Giant Kelp, Macrocystis pyrifera on lines. The kelp farm had large kelp crabs which aggregated because the kelp is their preferred food, similar to insects eating on our crop fields on land. The cute baby kelp is shown below growing on lines, hopefully they will not be eaten and make it to adulthood. It was an interesting experience seeing an underwater farm, its easier to farm in the water with kelp as the nitrogen fertilizer is naturally in the water!
For those of you vertebrates who still have their holiday decorations up, here is an invertebrate you might enjoy learning about: the Christmas tree worm. These polychaetes, Spirobranchus giganteus, are tube-building worms that have two “crowns” in the shape of Christmas trees, hence their name.
Many Christmas tree worms assembled together.
These appendages are an extension of their mouth and catch prey that swims by and then transport it by cilia to the worm’s mouth. Additionally, the appendages act as part of the worm’s respiratory system, and are thus commonly referred to as gills. Christmas tree worms are generally found in tropical waters and live within corals in calcareous tubes formed by the worms.
The appendages on these polycheates aid in the catching of prey.
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