Invertebrate Spotlight: Larvaceans

Mucus house of a Larvacean

Invertebrate Spotlight: Larvaceans

By Michelle Marraffini

Invertebrate Zoology Lab

Today in the Marine Invertebrate Zoology we learned about one of the most interesting marine animals.  Larvaceans (Class Larvacean) are unique animals in the phylum Chordata along with their close relatives sea-squirts (Class Ascidiacea) and slightly more distant relatives humans (Subphylum Vertebrata).   These chordates retain their tadpool larva form and excrete a mucus house from specialized cells located on their head.  This house starts off as a small balloon like structure, the tadpole Larvacean whips its body to inflate the balloon with water, then when it is big enough the animal crawls inside, and whips its tail to continue to inflate the house.  Larvaceans will also eat with the help of their house which also contains screens set up to filter water, water is then further filtered by the animal so that it can eat bacteria sized particles.

A schematic of a larvacean in its house with the screens and showing water current flow. Photo Credit: Earthlife.net

They live in this house until the screens become clogged and then they swim out of it start to make a new one.  They discard their old house with sinks to the ocean floor as marine snow.  Marine snow is considered a big source of nutrients to the deep sea, to learn more about how larvaceans contribute to marine snow check out MBARI’s website.

Larvacean photo, screens shown in red tint, white folds are more filtering tools, and the animal itself is in the center of it’s house. Photo Credit: Arctic Exploration 2002, Per Flood, NOAA/OER

Tis the season for MLML Open House

The vertebrate ecology lab’s recreation of the inside of a whale. (photo by The Moss Lander).

Tis the season for MLML Open House

By Michelle Marraffini

Invertebrate Zoology and Molecular Ecology Lab

The spring semester is buzzing with activity from classes, field trips, and preparing for Open House.

Have you ever walked inside the belly of a whale?  Want to know how long turtles live or what seastars eat?  This year’s Open House will answer these and so many more of your ocean questions.  Be there Saturday April 20th and Sunday April 21st from 9am to 5pm.  As a FREE EVENT we offer a marine adventure puppet show, education presentations by students and faculty, live touch tanks, a sea lion show, raffle and prizes, and so much more.  There is so much to see you will need to come back both days!

Entry Way to MLML. Dive into Open House! April 20th and 21st
Photo by: Scott Gabara

What’s that on the rock?

What do you see on the rock?

What’s that on the rock?

By Michelle Marraffini

Invertebrate Zoology Lab

The invertebrate zoology class took a field trip to Asilomar State Beach last week to look for cool creatures.  Professor Jon Geller encouraged us to turn over rocks looking for flatworms, the topic of this week’s lecture.  As I overturned one rock I noticed something quickly hunker down.  It was this tiny octopus that tried to camouflage itself with the rock.   An octopus’s boneless body is well suited for changing its shape and its ability to mimic other animals, algae, and rocks or sand can be quite impressive.  Check out this video of an octopus camouflaging itself (‘Where’s the Octopus?‘).  These extraordinary animals are different from other camouflaging animals because they not only change their color and shadow but they also change the texture of their skin to match their background and they do all of this by sight!

Their very kein eyes detect the object they wish to look like and control over 30 million chromatograms (color producing cells) and papilla (cause the three dimensional shape of the skin).  Octopus’s do this while color blind which mystifies scientists.

Small octopus found at Asilomar State Beach hiding under a rock at low tide.

This octopus I found is likely a Pacific red octopus (Octopus reubescens), though it swam away before I could get a good look (no animals were harmed in the making of this blog post).  This is so far the coolest creature I have seen in the intertidal.  Get outside and see what you can find!

My little buddy swimming away.

A Point Sur Adventure

Marine Ecology students on the Point Sur cruise sort and record organisms from the Monterey Bay.

The Marine Ecology class embarked on a seafaring adventure last Monday on the Moss Landing research vessel the Point Sur to observe the biota of the Monterey Bay. The class was joined by members from the Monterey Bay Aquarium, MBARI and even Professor Emeritus Greg Cailliet who arrived bright and early for a 7am departure time.

After braving choppy water and a bit of rain we began our day with a beam trawl, designed to sample creatures from the ocean floor at 600 meters depth. Unfortunately we were left empty handed when the net returned to the surface with a hole caused from large rocks lodged in the net.

Despite our first strikeout, our second mid-water trawl yielded a wide array of fish, crustaceans, jellyfish, and a plethora of other gelatinous creatures. Once on board the Point Sur, each animal was classified into separate glass dishes and recorded, giving the students a chance to practice their species identification and exercise their Latin nomenclature.

The highlight of the trawl (quite literally) was a group of fish called the Myctophids, or Lanternfish. These fish have light emitting cells called photophores that help camouflage them in the deep ocean waters in which they live. Lanternfish regulate the photophores on their flanks and underside to match the ambient light levels from the surface, rendering them nearly invisible from predators below.

Lanternfish emit light from cells called photophores that help camouflage them from predators.

The last tow of the day was called an otter trawl; but don’t worry, we didn’t catch any sea otters.  This net is name for the ‘otter’ boards positioned at the mouth of the net designed to keep it open as it travels thought the water. The animals are funneled to the back or ‘cod’ end of the net and are brought to the surface for the class to observe.  We saw several species of flatfish including the Sand Dab, Dover and English Sole, several dozen octopuses (or octopodes depending on your dictionary) and even a pacific electric ray.

After a long day of sunshine, high seas and amazing sea creatures the Marine Ecology students were excited with their discoveries, but also ready to be back on solid ground.

Fish Feeding Frenzy

In the southern California bight, the channel islands archipeligo 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!

The Early Bird Gets the Fish in this Case (and a Great Tide-Pooling Experience)

By Catherine Drake, Invertebrate Zoology Lab

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.

That’s Not a Seashell!

By Michelle Marraffini

Invertebrate Zoology and Molecular Ecology

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.

Battle Under the Docks

By Michelle Marraffini

Invertebrate Zoology and Molecular Ecology Lab

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

The Unseen Elkhorn Slough

By Gabriela Navas, Invertebrate Zoology Lab

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. Check this out:

http://rspb.royalsocietypublishing.org/content/early/2010/09/16/rspb.2010.1753.full

So, next time we take a stroll around the slough – let’s chat about the unseen, shall we?

The Ballast Water Balancing Act

By Catherine Drake, Invertebrate Zoology Lab

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.