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Project Lab 

May 29, 2013

Nudibranch scientist/dentist

As many of you know, and perhaps many of you don’t know, behind the scenes we have about 28 million specimens and several lab spaces where we investigate the diversity of life on our planet.  The Project Lab is just a glimpse into some of the research that happens at the Academy.   In the Project Lab, we have two stations where we can take high resolution images of tiny, microscopic ones (tiny seeds, insects, etc.) to large macroscopic specimens (fish, lizards, etc.).  We take photos of specimens for many reasons, but most importantly is to communicate with others online or in publications.

SEM wcap

Lately, I’ve been working at an imaging station that you can’t see though the windows of the Project Lab.  I’m talking about our scanning electron microscope (SEM).    Our SEM is located on the bottom level of the building since it needs to be on stable ground to prevent movement of the microscope. The SEM is a type of microscope that uses electrons, instead of light, to create an image and is able to produce images at a very high magnification.  These images tell us about the shape and texture or topography of different types of specimens.  Some examples of specimens that biologists may image with an SEM include pollen grains, insect and spider genitalia, insect eyes, etc.   As for the nudibranch lab at the Academy, we use the SEM to take images of a part of a nudibranch called the radula.



So what is a radula?  The radula is the feeding structure of most mollusks (snails, slugs, squid, etc.).  It is a sheet or ribbon-like structure that is made up of teeth that are made out of a substance called chiton.   The radula is located inside the mouth-end of the mollusk and then comes out of the mouth to be used in scraping, cutting up or grasping food.  In nudibranchs (and other mollusks), the radula is often used in species identification, so we often find ourselves cleaning and preparing nudibranch radular teeth under the microscope to take their picture.  Although I did want to be a dentist when I was in the third grade,  I never could have imagined that I’d be a slug dentist when I grew up!


For many groups of nudibranchs, the radula will look different based on the species it came from.  Major groups of nudibranchs will have similar looking radulae, and then within that group you will see variations.  One reason for different types of radulae and different shapes of teeth is that different nudibranchs (and other mollusks) have different types of prey.


Let’s take a look at some nudibranch radulae images taken with an SEM…


Ancula gibbosa wcap




C. magnifica wcap

This is just a small slice of the diversity of radulae found in the mollusk world.    I’m going to get back to documenting some of it, so that’s all for now!  Till next time…

Vanessa Knutson

Project Lab Coordinator and Graduate Student

Filed under: Uncategorized — project_lab @ 1:12 pm

May 22, 2013

Extinction is Forever (continued)- Are We Losing the Monarch Butterfly?

In past blog posts I have talked about the extinction of several species of California butterflies, each of which had small, localized populations, which tend to be extremely vulnerable to even small changes in the quality or amount of available habitat.  Environmental scientists and conservation biologists generally agree that habitat destruction and degradation are at the top of the list when it comes to why we are losing so many species of animals and plants around the world today.  Unfortunately, it is the ever-expanding human population which is putting so much pressure on habitats, both directly, as we need to find places to create housing and work, and indirectly, as we need an ever-growing food supply to feed the burgeoning masses.  The use of modern technology has increased our output of food per acre, but at what cost?




For some time now, entomologists have noted a slow but steady decline in the populations of butterfly species overall, (as well as other insects), but in some cases they are seeing a rapid decline of certain species. The iconic Monarch butterfly, Daneus plexippus is one such example.  Perhaps the best known butterfly in the U.S., the Monarch has 2 large American populations famous for their long migration from as far north as Canada, down to their summer grounds in Mexico. Biologists estimate the populations by counting the overwintering butterflies, and this year’s count was the lowest ever recorded, leading to fears that the Monarch may be headed for extinction.

Male Monarch


The host plants for the Monarch are all species of milkweed, which give both the larvae and adult butterflies protection from predators, because milkweed contains a poisonous cardiac glycoside that is distasteful and toxic. The adults also nectar mostly on milkweeds, along with several other species of flowers.


There appears to be 2 main reasons for the Monarch’s decline.  The first has to do with modern agricultural methods involving genetically modified corn and soybean crops designed to make them immune to the effects of the herbicide glyphosate, also known as Roundup.  These modifications allow farmers to plant their crops and then spray the entire field with herbicide, killing all the weeds including milkweed, leaving only the soy or corn.  Because of the vast areas planted in these crops, millions of acres of milkweed have been eliminated from Midwest farmland, leaving no host plants for the larvae to eat.

Female Monarch

The second reason appears to be warming temperatures caused by climate change, brought about by our consumption of fossil fuels that produce carbon dioxide as a byproduct. Temperatures above 95 degrees and hot, arid conditions can be lethal to larvae and eggs.


Will people care enough to bring about the changes needed to save these and other species, or will they be allowed to slide into extinction?


Until next time,


Vic Smith

Curatorial Assistant and Imaging Specialist

Department of Entomology

Filed under: Uncategorized — project_lab @ 10:52 am

May 15, 2013

Jeju Island: Island of Peace


A few weeks ago in our Project Lab blog, there was a discussion about what constitutes an “animal” and how this may influence the way we make decisions about conservation.  A polar bear may be more charismatic than a shrimp or a coral to some, but there are many invertebrate species that still need our attention even if they don’t have the same “cute” factor.  Have you ever heard of the Boreal digging frog (Kaloula borealis), or the Red-footed crab (Sesarma intermedium)?  These are two endangered species that reside on Jeju Island, an island off the southern coast of Korea. Island species can be especially sensitive to any changes in habitat due to their isolated evolution.  Whether it is inter-specific competition between native and non-native species or habitat degradation leaving species with limited space to relocate, population decline can happen quickly in smaller island populations.  While this frog and crab are not necessarily cuddly, they still are an important part of a local ecosystem and need to be recognized.




Jeju Island, situated about 270 miles off the southern coast of the Korean peninsula, is a distinctive island ecosystem and culture. Known for its great natural beauty, Jeju Island is home to the Jeju lava tubes, a UNESCO World Heritage Site designated in 2006, as well as beautiful soft coral reefs and bountiful farmland.  These soft coral reefs and coastline of volcanic rock, known as gureombi, are habitat to many different types of invertebrates that are harvested by haenyo, or free divers.  A group comprised mainly of women and representing the matriarchal structure in Jeju, these haenyo collect marine invertebrates from the coastline for food as well as income.  Leading into the ocean are freshwater streams and ponds that have created fertile farmland for a variety of crops.  Inhabiting the surrounding areas of terrestrial and freshwater ponds and streams are Sesarma intermedium, and Kaloula borealis, both considered Class II endangered species under the Ministry of the Environment of South Korea.  This means that these species are under threat of extinction due to natural or human factors.




The Red-footed Crab (Sesarma intermedium), is a terrestrial crab that lives in wetlands and freshwater close to the coastline.  Although they spend the majority of their time in these freshwater environments, once the females release their eggs, the eggs must travel downstream to saltwater in order to hatch.  Adult crabs have been known to rest and feed in the rocky coastline of gureombi.

The Boreal digging frog (Kaloula borealis), is a small amphibian with a range throughout Northeast Asia.  Living in farmlands such as rice paddy fields and breeding in small ponds or rainwater pools this frog is common in the majority of its habitat, but considered endangered within the Korean peninsula due to habitat degradation and loss of breeding areas.  These frogs belong to a group known as “narrow mouthed frogs,” meaning their body shape is more oval with the mouth area smaller than its wider anterior end.  A nocturnal species, these frogs emerge from an underground burrow at night to hunt small insects.



On the southern coast of Jeju Island is a small area designated an Absolute Conservation Area by the Korean government, as well as a Natural Memorial by the Cultural Heritage Administration of Korea and can be called home to both these endangered species.  Sitting amongst these protected areas is Gangjeong village.  Initially proposed in 1993 but starting in 2007, plans have moved forward to build a Republic of Korea/US military base in Gangjeong.  While not all the villagers oppose the base, it has become a deeply divisive issue within the community.  Those against the construction of the base fear it threatens a way of life of the people in Gangjeong, like haenyo and farmers who rely on the soft coral reefs, gureombi and surrounding freshwater for food and spiritual connection.  Once teeming with life, the gureombi has recently been paved over with concrete and pillars erected next to the soft coral.  Also considered a sacred space, the loss of the gureombi is seen as not only as loss of species habitat, but also a loss of cultural heritage.

The government has worked to relocate the endangered species on Jeju, however more long term data is usually needed for these types of studies to determine success.  Habitat restoration or relocation to new areas can sometimes be viable options for species facing loss of natural habitat, but ecosystems are complicated. Many of the finer complexities and connections are still unknown to researchers making it difficult to recreate ideal conditions.  This belief that natural habitat should be conserved for all species using the area has led to calls to halt construction efforts in Gangjeong.  Currently construction plans continue.  In situations like these, it can be tough to determine what is the best course of action. As mentioned before, conservation can be influenced by our perception of what needs protection and what species are important to a fully functioning ecosystem.  In the case of Gangjeong village, we can only hope that our voice is heard and that all sides are considered before completely and forever altering a habitat found nowhere else.


Codie Otte

Curatorial Assistant and Specimen Preparator

Ornithology & Mammalogy Department

Filed under: Uncategorized — project_lab @ 9:45 am

May 7, 2013

Surveying Danajon Bank, a fragile reef

Photo 2

See prior post from February 6


I have returned from a two-month adventure working in the Philippines for the non-government marine conservation organization, Project Seahorse. I was assisting with the long term monitoring (LTM) of the marine protected areas of Danajon Bank, which is one of six double barrier reefs in the world, North of Bohol. A team of us conducted surveys for ten marine protected areas (MPAs) and four control sites.  An MPA is a part of the ocean set aside for protection, while a control site is an unprotected patch of ocean.  Danajon Bank is a highly threatened reef, due to a variety of factors including: overfishing, the use of highly destructive fishing methods, pollution, the aquarium trade, and climate change. Filipinos receive most of their daily protein from fish and heavily depend on the ocean for their survival. Because of this, it is dire that the Philippine oceans continue to gain further protection- so that future generations can prosper.


Photo 3


The surveys included a fish visual census, collecting data for measuring coral cover, and snorkeling at night in search of the endangered tiger-tail seahorse, Hippocampus comes. The fish visual census entailed notating the number of fish observed from 22 different families and their relative sizes along a shallow and deep transect. For collecting data on coral cover, a lightweight metal chain and a camera attached to a metal stand (monopod) were utilized. The lightweight chain was rolled out alongside the transect to measure vertical coral growth and a photo of coral cover was taken every meter for statistical analysis. To search for the tiger-tail seahorse, a specially made lantern was strung onto a small banca (Filipino boat), which was pulled along by a fisher while snorkeling.

Photo 1


A healthy reef will possess a greater diversity of fish and coral cover. Unfortunately, there are still several unsustainable fishing methods practiced in the Philippines. One of these devastating methods, is dynamite fishing. This method involves strategically throwing dynamite into a school of fish, which in the process blows up the surrounding coral. It severely impacts the reef ecosystem since the coral provides food and habitat for so many other marine organisms.

A valuable component of these surveys was our interaction with the local people and educating them about their reefs. We stayed in the homes of community members on remote islands and met with government officials to inform them of our work.


Photo 4


Overall, this experience was an eye opener for me as a marine biologist and

conservationist since it directly connected me to the fragility of the oceans and the people whom which depend on it for their sustenance. To learn more about my experience, you can read my Young Explorers feature on the Mission Blue/ Sylvia Earle Alliance website http://mission-blue.org, which will be posted by June 2013. Mission Blue is a community of 60+ highly regarded ocean conservation groups and organizations, which raises awareness about the ocean and major issues surrounding it.


Carissa Shipman

Graduate Assistant in Public Programs

Invertebrate Zoology and Geology

Filed under: Uncategorized — project_lab @ 4:35 pm

May 1, 2013

Record Breaking! A rare bird becomes a part of our collection

If someone were to ask you if you had heard of a bird called a Booby, you might instantly think of the Blue-footed Booby (Sula nebouxii). They breed on the Galapagos Islands and are named for their feet that are an unnatural-seeming shade of blue. Blue-footed Boobies have one of the most charming mating dances I’ve ever seen – they’re no birds-of-paradise in the dancing department, but still flashy in their own way (go look up some videos online – you won’t be disappointed.)

Large seabirds that are often found in tropical waters, Boobies are a spectacular group of birds. Like pelicans, they dive into the water from a great height to pursue fish, and have air sacs under their facial skin to help cushion the impact when they hit the water. There are six species in the genus Sula: the Masked Booby (Sula dactylatra), Nazca Booby (Sula granti), Brown Booby (Sula leucogaster), Blue-footed Booby (Sula nebouxii), Red-footed Booby (Sula sula), and Peruvian Booby (Sula variegata).  We don’t usually get a chance to see them up here in Northern California, but occasionally one will be sighted somewhere along the California coast.


Picture 1_ed


Recently, the marine mammal Curatorial Assistant from our department, Sue Pemberton, was called out to Bodega Bay to respond to a California Sea Lion stranding. This is a typical call for Sue to get, as she takes measurements and samples from dead marine mammals that wash up on the beach. Sue noticed that there was something else washed up nearby: a seabird (pretty typical, again, to find on the beach). When she got close, she realized that it looked like a Booby, which was a shock to her as they’re not common in California. After bringing it back to CAS, it was identified as a Brown Booby. Not only was this a rare species for us it get, it turned out to be the first Booby record ever in Sonoma County – no species of Booby had ever been seen there. What a find!

I didn’t think it would be salvageable as a study skin, as it had been partially scavenged by other animals. I was determined, however, to give it a shot. Such a rare specimen deserved to be preserved in a way that researchers could look at its feathers, as opposed to just its bones. I quickly found out that it was skinnable and that the holes scavenged by other animals could easily be sewn up. I also decided to detach one wing and prepare a “spread-wing” so that researchers could see all of the flight feathers. After getting a good bath to remove all of the sand, it ended up looking great.

Picture 2_ed


This is one of the things that I love about my job: getting to do the hands-on work to prepare unique specimens for the research collection. Even though I’ve seen Brown Boobies when traveling in Central America and Mexico, it’s still exciting to see one up close and I never thought that I would get the chance to prepare one. This specimen will be an important addition to our collection for many years to come!


Laura Wilkinson

Curatorial Assistant

Ornithology & Mammalogy

Filed under: Uncategorized — project_lab @ 10:30 am

April 26, 2013

What is an animal?

It may seem like a basic question, but ask someone and listen to the variety of responses that you get and sometimes, a bit of confusion and uncertainty.  This week I’m going to diverge from my recent themes of fieldwork, research and nudibranchs and focus on something a little bit more central to biology.

A couple years ago, I was designing an activity for a lesson plan (see it here).  The activity was based on the game “Guess Who,” but features some classic California coast animals including some fish, sea urchins, and sea anemones.  When it came time to test it out, I asked a (non-biologist) friend of mine to play with me.  Halfway through the game, my friend made a comment about how half of the cards weren’t animals.  WHAT???  I was taken aback, why of course they are ALL animals!   Here is the dialogue that followed,


Me: Well, how do you define an animal?

Friend: Something with a face.

Me: Do you consider an insect to be an animal?

Friend: No.

Me: But insects have faces…

At this point, another friend jumped in

Friend2: Oh I know, an animal produces milk, has hair and…

Me: That’s the definition of a mammal!


And that seems to be the source of some of this confusion.  Many folks confuse the definition of “animal” with the definition of “mammal,” or sometimes “vertebrate.”  But the reality is that mammals (approximately 5,700 described species) and vertebrates (animals with a backbone, approx. 62,000 described species, including mammals) make up a small minority of the animal life on our planet. The vast majority of the animal life on our planet are invertebrates (animals without a backbone) including insects, spiders, snails, clams, seastars and many animals that your wildest dreams couldn’t imagine (approx. 1.2 million described species, with many more to be discovered).


So what is an animal, then?

First thing’s first.  All of the categories of life that you may hear about are created and defined by humans to better understand the life on our planet.  The categories themselves change as we learn more about the relationships between different living things.  Occasionally, some organisms do not fit neatly into the categories we’ve created, and the following is my attempt to simplify this, so it should be taken with a grain of salt.  If this stuff truly interests you, I encourage you to learn more because the life on our planet is SUPER fascinating stuff!  That’s why I became a biologist in the first place. : )

To be an animal, you must be a living thing and you must be made up of many cells (multicellular). This criterion alone eliminates the bacteria and some other living things called archaea and others called protists.   Oh and by the way, not only must you be multicellular, but you have to be made up of cells that have their insides bound up in membranes (these are called eukaryotic cells).   Bacteria and archaea have cells that lack these internal membranes, and are not multicellular, so they definitely do not fit the definition of an animal.

Animal cell


There are some additional requirements to qualify as an animal.  To be an animal, the cells that make you up must form specialized tissues or you must be made up of different types of cells.  You also cannot have a hard structure around your cells called a cell wall.  Multicellular living things that have cell walls made up of a substance called cellulose are what we call plants, and most plants use energy from the sun to create their own food (the process known as photosynthesis).  Animals cannot directly undergo photosynthesis (I know of some sea slug exceptions to this rule!).  Multicellular living things that have cell walls that contain a substance called chitin are what we call fungus (though there are some species of fungus that are single-celled, but let’s not get too complicated today).

Eukaryota_cell_structure plantcap

So the next time you wonder, is that an animal?  You could run through the above requirements (multicellular, cells with no cell wall and cannot make its own food through photosynthesis), though that might seem a bit overwhelming.  Often time if someone asks me if something is an animal, I’ll just ask, well, is it a plant or a fungus? If not, then it’s likely an animal since you can’t see most bacteria or archaea with your naked eye and unless you are looking under a microscope you are unlikely to observe any protists in person.  I will admit that some animals, like corals and sea squirts can be a bit tricky since they don’t move around much, and some folks might mistake them for plants, but the most important thing to remember is that things like insects, corals and worms are animals!

So why does this matter?  I can think of several reasons why this matters, but I will focus on 2 main reasons:

1.  People’s understanding of this directly impacts conservation.  For example, corals are animals and some species of corals are responsible for the beautiful and economically important coral reefs on our planet.  If people do not understand that these are animals, how will we understand the threats they face (pollution, climate change, ocean acidification) and how to protect them?

2. By ignoring the animals that don’t have faces, or don’t have hair, you are missing out on the majority of the animal life living on our planet, and you are missing out on some pretty cool animals that have life histories that are far more interesting than any science fiction I’ve ever read.

So until next time, enjoy one of my favorite invertebrate animals…



Vanessa Knutson

Project Lab Coordinator and Graduate Student

Filed under: Uncategorized — project_lab @ 10:37 am

April 17, 2013



Is this a fantasy, or could it be true? This bogus headline describes a real event that took place in 2005, when Lori Bell and Pat Colin of the Coral Reef Research Foundation were diving off of Palau in the Caroline Islands using the Deep Worker Submarine. While working at depths between five hundred seventy and six hundred seventy feet they encountered and collected 2 specimens of an apparently unknown species of nudibranch.


Those of you who have been following our Project Lab blog have already been exposed to the wonderful world of nudibranchs. For those who haven’t, nudibranchs are marine slugs that have fascinated divers, tide-poolers and researchers alike with their often fantastic and beautiful appearance and their interesting behaviors.

While the majority of nudibranchs are relatively small, (less than an inch to a couple of inches), this bright-red monster was over four inches long, and sported a veritable forest of branched tentacles (branchial plumes) used to increase surface area for ‘breathing’. Nudibranchs have been collected by divers to a depth of about two hundred fifty feet, and at far greater depths by dredging from boats, but a collection from this depth was very unusual.

The collectors sent the specimens back to California Academy of Sciences to “Nudibranch Central,” the lab of Dr. Terry Gosliner for identification. At that time, I was a Masters student in Terry’s lab, working on the nudibranch family Tritoniidae, of which this beast appeared to be a member. We knew right away that this was a new species, and set about describing it.


Marionia bathycarolinensis (Smith and Gosliner) was described in 2005 in the Proceedings of the California Academy of Sciences. Very little is known about the life of this animal, but we were able to determine what it was eating by examining stomach contents. With the help of Dr. Gary Williams (Octocoral Research Center at the Academy) we identified an octocoral of the genus Paracis as the sole stomach contents. This was the first record of an association between a nudibranch and this genus of coral. Tritoniid nudibranchs use an oral veil with tentacles to sense their prey, and jaws to grab and bite the coral polyps while the rasp-like radula scrapes away and pulls in tissue. The corals have calcified plates or spicules that must present a problem to digestion, but this family of nudibranchs has a series of hard plates in its muscular stomach (see a. and b. in the photo above) that help grind up the coral skeleton.


The jaws of this nudibranch were unusual in having a set of rodlets (see photo above) instead of teeth on their chewing edge, and other anatomical features helped differentiate this animal from all others in its family. As far as I know, it hasn’t been observed or collected since.

Until next time,

Vic Smith

Project lab imager and recovering nudibranchaholic.

Filed under: Uncategorized — project_lab @ 10:45 am

April 10, 2013

Specimen of the Day: Brown Creeper

Sometimes I find myself staring up into a tree and losing myself in thought. At times it is productive thought but sometimes I’m just gazing, thinking of nothing in particular. There’s the rare occasion, though, that I’m rewarded by a glimpse of a Brown Creeper making its way up the tree trunk searching for small and tasty insects. Though not an often occurrence, it’s always exciting to watch these small birds as they forage from tree to tree and I get the feeling that many may often overlook these residents of San Francisco.


The Brown Creeper (Certhia americana) is the only species of treecreeper that occurs in North America – other treecreepers can be found in Europe and parts of Asia. Here in North America, Brown Creepers can be found, as their name indicates, creeping up the trunk of a tree. Starting at the bottom, they have a unique spiraling trek up and around the trunk looking for insects and then when they reach the top they fly to the base of their next trunk. Much like woodpeckers, Brown Creepers have a stiff tail that they use as leverage as they inch their way up. Their brown mottled coloring makes them difficult to see against the bark so you may have to take a second look to find these birds!

I’ve seen these birds at Sutro Heights, Stow Lake and also in Cole Valley, so they aren’t impossible to spot while out and about. One other place to check out these birds is in the research collection at the Academy of Sciences. Since the study skin that I prepared this weekend was found in San Francisco, comparing it to other Brown Creepers found in the City can identify regional differences of the Bay Area population. Within each population of Brown Creepers there can be slight color variations from brown to brownish-red to grey. Using the research collection, scientists can also study these morphological trends over larger geographical regions like North America, even over the last few decades! In the next photo, you can see that some of the specimens in the research collection were found in the late 1800s to early 1900s. Looking at these specimens from over a hundred years ago gives researchers a baseline of historical data to use in their research about how these birds have potentially changed over time. Who wouldn’t want to study these amazing birds?!


Codie Otte

Curatorial Assistant and Specimen Preparator

Ornithology & Mammalogy Department

Filed under: Uncategorized — project_lab @ 11:16 am

April 3, 2013

A Mouse? A Bird? It’s a Mousebird!

Recently, I’ve been preparing some very cool specimens from South Africa. South Africa has a unique array of habitats and an incredible amount of biodiversity, which means that it is home to a wide variety of animal and plant species. There are 858 bird species found there! Here, you can see six different species that I pinned to dry.


Although all of the different species are equally interesting, one of my favorites is a unique bird called a mousebird. There’s not a lot of recent research published about these birds, so they are an invaluable part of our collection. Historically, mousebirds were found in Europe, but presently are only found in Africa. They are the only species in the family Coliidae as well as the order Coliiformes, and there are only six species total. So, why are they called mousebirds?


As you can see, they have very long tails and their body feathers are short and fur-like. An even more interesting feature is the fact that they can rotate their first and fourth digits on their feet to effectively grasp on to a variety of surfaces. This allows mousebirds to scurry along the branches of trees, much like a mouse might. Combined with its physical appearance, it’s clear how this bird got its name.

In our research collection, we have specimens of four of the six species of mousebirds, three of which are found in South Africa. The Blue-naped Mousebird, third bird from the left, is found in Eastern Africa. Having these study skins gives researchers the opportunity to learn more about these fascinating birds.


It’s always a nice change to be able to prepare study skins of birds that aren’t from California. If you ever are lucky enough to travel to Africa, hopefully you’ll catch a glimpse of a mousebird before it scurries away!

Laura Wilkinson

Curatorial Assistant and Specimen Preparator

Ornithology and Mammalogy

Filed under: Uncategorized — project_lab @ 12:30 pm

March 27, 2013

Preserving Slugs

Last time I wrote about how we collect nudibranchs in the field. This time I want to tell you a little bit about the preservation process.

First, I’d like to explain briefly why we make collections at all. Here at the Academy, and other natural history museums around the world, we have a library of life— preserved specimens collected from different locations and different times. We have everything from plants to insects to fish to my favorite- nudibranchs. These collections allow biologists to study the biodiversity of our planet and to study how populations and species of living things change over time. This is an aspect of the Academy that you may not see directly when you visit, but behind the museum walls, there are about 28 million specimens and several biologists that study them.


Different groups of organisms have different methods of preservation. If you were to visit the collections, you would find pinned insects, dry shells, bird and mammal skins and many specimens in jars. The method of preservation depends on the nature of the animal (Does it have a soft body? A hard exoskeleton? Does it have parts that will dissolve in a certain kind of preservative?), the history/tradition of research on that organism and the preferences or convenience of the people doing the collecting. The nudibranchs on our shelves are mostly initially preserved (fixed) in ethanol (ethyl alcohol, the same stuff as in drinking alcohol), formalin (a solution of formaldehyde, which is a gas), or Bouin’s solution (a solution of picric acid, acetic acid and formaldehyde). Each preservation method has pros and cons, depending on what you need from the specimen.


Many of our older nudibranch specimens were initially preserved in formalin or Bouin’s solution. These preservation methods are great for preserving soft tissues, which make dissection a lot easier. This is useful when we are interested in looking at the internal differences or similarities between species. However, these solutions can degrade DNA. Because I use DNA as a tool for my research, I need specimens that have been preserved in ethanol. Unfortunately, because many of the older specimens were preserved in formalin or Bouin’s solution, I cannot use them in my DNA study. However, these specimens are far superior for dissection, so either preservation method involves some compromise.

So how do we preserve them?

As just about anyone who has ever seen a nudibranch will tell you, nudibranchs are BEAUTIFUL creatures. Some refer to them as the butterflies of the sea because they are so charismatic and colorful. Unfortunately, no matter what solution we preserve them in, they lose their color (we sure wish this wasn’t the case, as they’d be a lot more exciting to show the public if they still had color!). This means that it is essential to document what these animals look like while they are still alive. This is why photography is so important for what we do. Without a photo, we have no way to know what the animal looked like when it was alive.


After we photograph the animals, we put them to sleep (anaesthetize them) using a solution of magnesium chloride and seawater. How long it takes for them to drift off into dreamland depends on the size of the animal- the larger the animal, the longer it takes. I’ve spent several nights up until ungodly hours waiting for these slugs to become anaesthetized. Once the nudibranchs stop moving, we place them in the preservative (ethanol, formalin, or Bouin solution).

If the animal is preserved in alcohol, it should be good to go for DNA extraction. Unfortunately, these alcohol-preserved specimens become very brittle, which makes dissection very challenging. The bodies also tend to become a lot more distorted when preserved in ethanol. One alternative is to take a small piece of the animal to store in ethanol, while the rest gets preserved in formalin or Bouin’s solution. However, a problem with this method is that if you run out of the DNA extraction, you can’t extract any more DNA!

Ultimately, each method of preservation comes with some sort of compromise, but the ultimate goal is to preserve these specimens to better understand life on our planet.

That is all for this week. Till next time!

Vanessa Knutson

Project Lab Coordinator and Graduate Student

Department of Invertebrate Zoology and Geology

Filed under: Uncategorized — project_lab @ 9:41 am
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