How to become a Marine Biologist*

I should start this blog with the qualification that *I am a Biological Oceanographer, not necessarily a Marine Biologist. However, I know from personal experience that most kids dream about being a Marine Biologist and don’t often know what a Biological Oceanographer is! At the most basic level, a Biological Oceanographer is equivalent to a Marine Biologist: they both have extensive knowledge about marine life. The main difference is that an Oceanographer of any sort tends to think on a more global scale and is able to connect the biology to larger scale processes.

So how does a person become a marine biologist? I can only speak from my personal experience which is unique, but I think these are some of the most important traits, experiences, and interests you should have that can help you get there.

Step one: Have a real love for and fascination with nature. I have always loved nature. Since I was a kid I would spend all my free time outdoors playing around our yard or in the nearby woods, wandering around exploring and sneaking up on deer or other wildlife. Since I grew up in Wisconsin, USA, the nearest thing to the ocean within 1000 miles were lakes and ponds. So I spent many summers with family or friends fishing, swimming, and enjoying time on or near the water.

Step two: Get involved! This is essential for anyone to find out what they really love and want to do for their career even outside of Marine Biology. If you don’t try it, you won’t know if it is really something you want to stick with for the long term. That is how I found my way to being a Biological Oceanographer. After attaining a Bachelor of Science degree in Biology from the University of Wisconsin Madison, I moved to Hawaii with my husband, Sean Jungbluth, and volunteered to do work with zooplankton in the laboratory of Dr. Erica Goetze. She taught me how to extract DNA from copepods, do PCR amplification of genes, and taught me some basics about DNA sequences. I was instantly hooked, and soon enough I applied to the Biological Oceanography program and started my Master’s Degree studying the zooplankton community in Kane‘ohe Bay, Hawaii.

Step three: Be diligent, creative, and determined. Not to mention the need to be organized (this can come with practice) and you need to be able to work well with others. A Marine Biologist is a scientist, and it is not always easy to be a scientist. Exciting discoveries are made after more trial and error than you might like, thinking about how to improve a method or how to interpret your results, a lot of discussion with others about ideas, and persistence!

Step four: Master as many disciplines as possible. I know this may not excite you, but it is true. You may not expect chemistry, physics, algebra, or sentence structure to be important when you are, for example, studying the mating behavior of the killer whale. However, knowledge of these and other disciplines are absolutely critical for sample collection or preparation (chemistry), experimental design (physics), interpretation of results (algebra), and sharing your work with the scientific community (sentence structure).

I realized recently that my 6^th grade time capsule predicted that I would be a marine biologist in 10 years! It took something more like 15 years, but was worth the wait. I doubt there were many others in my class whose time capsules were that accurate. Keep your eyes and mind open to potential opportunities, volunteer your time whenever possible, and you will find your way to whatever it is you want in life.

It’s not always bad to cross the line

Monday October 13^th was an exciting day for us at sea. This is the day we crossed the equator.

(photo of me in control room as we officially cross the equator) 0° 00.12’ N

After a restless nights sleep, I woke up at 01:30 am to continue my normal early-morning routine before the big “Crossing the Line” ceremony at noon. Most of my daily routine included picking out hundreds of ~8 different copepod species (microscopic shrimp-like insects of the sea) into cryogenic tubes until breakfast. After about 21 days at sea collecting samples, Erica Goetze and I had individually isolated over 10,000 copepods, and at this point we still had three weeks of daily sampling to go.

That morning, I received an ‘anonymous tip’ from one of the police (a double agent?) recommending that as inductees we plan effective defenses, since it would be more fun for everyone, so I made the last minute decision to save a portion of our stinky morning tow plankton goop for my defenses against King Neptune’s police force! This turned out to be quite useful when all of us not-yet-inducted line crossers got together before lunch to prepare our weapons: condom-water balloons!

(Photo of my weapons to fight King Neptune’s police force)

Why condoms? I would chalk it up to MacGyver-esque resourcefulness. The doctor had a large stock of condoms she did not mind sharing, since she too was crossing the line that day!   Condoms work quite well as water balloons. We also decided to include extra special “treats” in the balloons… purple dye, fabric softener for strong scent, and my favorite, the stinky plankton water. We then chose our hiding places, and I chose a location with two other line crossers, Ryan and Rafael.

At the strike of 13:00 the announcement came “King Neptune has arrived on the ship, and any non-shellbacks (those who have previously crossed the equator) are to be put on trial for their crimes against his subjects!” That was our cue to quickly get to our hiding places and be ready to defend ourselves against the police. Seasoned veterans of the ceremony were chosen as the police force, so we knew who to expect.

(Photo of us in our hiding location, on the defensive against one of the King’s police)

We were found within minutes. There have been many line crossings on this ship, the RRS James Clark Ross, so there are not many hiding locations left that the police don’t know about.

Once we were caught, trial and punishment were simple: sit before King Neptune and his lovely wife Aphrodite (i.e. John and Colin) and be put on trial. Guilt of a charge meant you received some volume of old, cabbage ridden, vinegary kitchen slop over your head, down your shirt, in your face… etc. Then before we were deemed an official “Shellback”, we had to kneel before the king and kiss a dead fish!

As you can see, not even I (sweet and harmless Michelle) was safe from the wrath of King Neptune! You might be wondering, what were my “charges”? In all I received 8 charges, here are a few of them:

• Forcing my study subjects through a tiny mesh thus causing a slow and painful death
• Pronouncing tomato incorrectly (according to the British dominating the science team)
• Distracting the bridge with my day-glo t-shirts
• Wearing a ridiculous fireman’s helmet
• Spending all day tanning at the CTD while I say I am working (I have to sit there for hours concentrating animals from the water!)

My hair exuded the scent of vinegar for at least three days afterward, and I am still finding remnants of our ‘water balloons’ on the deck of the ship despite an attempt to clean them up that evening. In the end, it’s all in good fun, and will be one of the most fun and memorable days of this shellback’s life.

Beautiful butterflies of the sea

Pteropods (or ‘sea butterflies’) are snails that are part of the zooplankton. As part of my PhD I am especially interested in shelled pteropods, the thecosomes (euthecosomes and pseudothecosomes; here I focus on euthecosomes). Also shell-less pteropods exist: gymnosomes. Pteropods have modified parts of their soft tissue to resemble paired swimming wings, using them to migrate vertically in the water column, coming towards the ocean surface at night. This is why we sample overnight. Most genera are epipelagic and are represented in our samples during the cruise, but a minority of species lives in deeper waters.

Cuvierina cancapae (photographed by Alice Burridge)

Euthecosomes have amazingly diverse shell morphologies and ontogenies (development of an organism). Limacinidae (Limacina, Heliconoides, Thielea) have characteristic shells that coil sinistrally (anti-clockwise direction) and are generally small in size (0.5 – 4 mm), one exception is the deep water species Thielea helicoides (up to 15 mm). Shells of Cavoliniidae have all kinds of shapes and are generally bigger than Limacinidae shells. Styliola, Creseis and Hyalocylis have pointy shells throughout their lives, with Hyalocylis striata having remarkable ribs on its fragile shell. Also Clio species have pointy shells, but they have a much broader aperture. Cuvierina species have large bottle-shaped shells (up to 10 mm). Cavolinia, Diacavolinia and Diacria have roundish, complex shell morphologies, with some Diacria species having long spines (such as Diacria trispinosa). Diacria danae and Cuvierina species shed their pointy juvenile shells before reaching their adult morphologies.

Apart from sampling, counting and preserving pteropods, I have also tried to run some experiments with them, but they are difficult to keep alive for very long. During the incubation the water had to be cleared from mucus regularly. Pteropods feed by building mucus webs in which they entangle food. These webs can be several cm wide, much bigger than the animals themselves. Although they were hard to culture, it was fascinating to observe the different ways they swim through the water column. For example, Creseis virgula swims with its curved tip pointing in its horizontal swimming direction, while the bulky and roundish Cavolinia uncinata and Diacavolinia clumsily and seemingly less efficiently try to swim along. Cuvierina cancapae is, when unharmed from the sampling procedure, a very active swimmer, its bottle-shaped shell tilting back and forth. Their active swimming does not seem to be the most energy efficient in the universe of zooplankton.

Cavolinia tridentata (photographed by Alice Burridge)

My most interesting catch during this cruise was a beautiful and big Cavolinia tridentata, probably a one-time catch. It took a while, but when it came alive in its jar it was too active to image using the microscope camera, and too big anyway (15 mm), so I tried to image it directly through the lens of the microscope. Quite some other scientists came over to gaze at this amazing creature. You could even hear it swim.

It only took us a few days to get through the tropics and now we are in the subtropics, which we are about to leave by October 23^rd already. Still, every time the net comes up it is a surprise what’s in there. The transition to a new oceanographic province is noticeable in the changing species composition. This shows that biogeographic barriers in the ocean do exist but they are not hard boundaries. As such, the tropical zone is a barrier for some species, but a niche for others. Some pteropod species have returned in our samples after having been absent in the tropical zone, occurring in both the northern and the southern subtropics. I wonder what I will find even further down south, apart from more turbulent waters.

The ocean is filled with undescribed species

And here is one of them. This beautiful reddish copepod is also in the genus Pleuromamma, and does not yet have a scientific name. I show this for those of you who don’t yet know that the ocean is a mysterious and relatively uncharacterized place, with lots of secrets left to uncover. Despite a decade of discovery in the international Census of Marine Life, there are still many marine species left to be discovered and described. For some faunal groups, the majority of the species present may be new to science. We tend to think of marine zooplankton as being relatively well studied, in comparison to the deep sea. However, even for surface zooplankton, I suspect that the majority of species may be undescribed in high diversity ocean regions, such as the subtropical gyres. Learning about this diversity is critically important to understanding how these communities function, and the role different species play in marine food webs.

This beautiful Pleuromamma copepod is distinct from both P. abdominalis and P. quadrungulata, with which it co-occurs here in the equatorial region. It has long been noted that there is variation in the presence and degree of development of spines on the antennules of Pleuromamma copepods. In the photo, you can see two animals, oriented head to head, with the top animal lacking the strong spines on the antennules that are very visible in the animal below. It turns out that this variation is informative, and can be used to distinguish good species. Stay tuned for an upcoming publication from Junya Hirai (University of Tokyo) on the genetic lineages within the ubiquitous species P. abdominalis. I hope to find the time to establish a name for this organism, along with the many other undescribed lineages within this nominal species. Establishing a new name for a species is an opportunity to honor your predecessors and acknowledge the heroes that inspired your scientific journey. I hope to name at least one of these species P. frosti, in honor of Bruce Frost.

Keep in mind that even though we are now out in the middle of the Atlantic Ocean, you don’t have to go very far to find new species. You may even have some right in your backyard. For example, I know there are some undescribed copepods in the coral rubble right along the beach at Diamond Head, at one of the most popular surfing spots on Oahu (my backyard at home in Honolulu). There are probably also a myriad of small, but important, and unknown species lurking in the habitats around your home. Find them and be amazed!

How to catch plankton?

Well… remember that plankton can range in size from things that are very, very small, like bacteria, to things that are really quite large, like giant jellyfishes? How we catch plankton depends quite a bit on what type of plankton we would like to catch. It is also important to know that things that are small tend to be very abundant in the ocean, and organisms become more rare as they increase in size. This pattern means that we can usually sample small volumes of water to study small plankton, and we need to sample very large volumes of water to find large plankton. If we focus just on the animals that are in the plankton (and not the smaller things), we usually sample them using a few different ways:

Bongo nets

Using plankton nets. People have been collecting planktonic animals in nets for hundreds of years, and this still remains the most common way of sampling. There are lots of different types of nets, some very simple and some very complicated. Some have very fine mesh and are good for collecting small animals (e.g. copepod nauplii, see posts by Michelle), and some have very coarse mesh and are good for collecting things like shrimp, or small fishes, that really are good swimmers. We have to tow the net quite a bit faster to collect animals that are good swimmers, because they can feel the net coming and and are quite good at escaping!

Cod end with plankton in a bucket

During the daytime, when there is sunlight on the ocean, they may also see the net coming, and be able to avoid getting caught. We are using two different types of nets on this cruise, and we are towing them in two different ways: (1) vertical tows of a 60 um mesh net to collect copepod nauplii (baby copepods), and (2) oblique tows of a bongo net (see picture), to filter larger volumes of seawater and collect larger animals in the upper ~ 350 m of the ocean. Oblique just means that we are towing the net at an angle (45 degrees), so the net is moving both along in the ocean horizontally as we are pulling it up towards the surface. We can filter more seawater this way, and collect animals that are relatively large and relatively rare. Once we get our nets back in, we rinse them and collect the plankton in our buckets (see picture of the collecting end on the net, which we call ‘cod end’). On this cruise we carefully split the catch of each net using a Folsom Plankton splitter (see picture of me in the lab splitting a sample).

Another way to catch plankton is by using the CTD Niskin rosette. Using the CTD rosette, we are able to collect and study plankton from particular depths in the ocean. This is important, because the ocean changes dramatically across depth, very much more so than across the surface of the sea (horizontally). Animals often like to live only at certain depths, and are very good at maintaining themselves where they would like to be in the water column. Most animal plankton are too rare to sample with a CTD rosette. We are using it to sample copepod nauplii, which are often very much more abundant than the adults.

There are yet other methods, which we don’t use on this cruise. For instance, while scuba-diving. Many planktonic animals are gelatinous, and are therefore very fragile and hard to collect without damaging them. Jellyfishes are one good example, but there are many other types of gelatinous plankton that you might not be familiar with, like ctenophores, or siphonophores (ever been stung by a portuguese man-o-war? that’s a siphonophore). In order to really see these animals as complete organisms, you need to collect them by hand.

Some kind of magic

Aye!

It has been a while since we left the port of Immingham, UK. Currently the scientific programme at the RRS James Clark Ross is in full progress. Our zooplankton sampling takes place during the night (except Michelle’s copepod nauplii net). Living on a boat on the big Atlantic Ocean for several weeks is very different from everyday life on land. The ground underneath your feet is constantly moving back and forth. It took me little time to get used to it and I didn’t get seasick, but the sea has not yet been very rough. 

Bit by bit we are getting used to a new biorhythm. It is a bit like living twice a 12h day instead of one 24h day. It is again nothing like the relatively normal days on land. Because we sample zooplankton at night, we have to sleep during parts of the day and again soon after dinner. There is even a dress code for dinner, which was a surprise to me, but apparently dressing up for dinner is a tradition of BAS (British Antarctic Survey). I share a cabin with two others, Michelle and Laura. We don’t have identical schedules, so unfortunately I sometimes wake up by an alarm that isn’t mine. Few people have private rooms.

In the end the new routines all serve our goal of getting more insight in the biodiversity of the ocean’s zooplankton, just to reveal some more of her many secrets. We’ve had some trial and error with the sailing and net deployment speeds, but we are getting there. Being able to observe and photograph living zooplankton under a microscope has some kind of magic because it normally isn’t possible. It is like getting a surprise present from the ocean every night. Sometimes target species are absent, sometimes abundant. I haven’t found all too many sea butterflies (pteropods) yet, but I expect to find more in the subtropical and tropical regions.

Soon we will reach the Azores. The next time we will have land in sight will take a while – we will sail around South Georgia on our way towards the Falklands.

Cheers!

Slow start

We had a slow start to the day today. Our 03:00 am bongo tow was not terribly successful, and we didn’t collect very many animals of interest (that we are targeting in our studies). That was a disappointment! However, because we didn’t have a lot of organisms that we wanted for our scientific studies, we had a bit of time to focus on other things, like imaging some of the animals we did collect. So today we were able to capture beautiful images of 2 of our target species, Pleuromamma robusta and P. gracilis, that are common copepods in open ocean environments.

These species are important in ocean biogeochemical cycles, because they migrate every day between the surface ocean (at night) and the twilight zone (ca 500 m). While they undergo these migrations, they move carbon and nitrogen from the surface ocean into the ocean’s interior and play a role in sequestering carbon from the atmosphere into the sea. Pleuromamma gracilis is a member of a cryptic species complex, and we are collaborating now with Janet Grieve (NIWA, New Zealand) on systematic revisions of this group, with descriptions of several new species.

In the afternoon, we also caught a Velella velella in our nauplii net. This funny jellyfish-like creature lives on the surface of the ocean, and has a clear sail that sticks up above the sea surface. The animal is then pushed by the wind across the ocean like a real sailor. This beautiful blue color is found in many of the animals that live at the air-sea interface.

Gooey yellow-brown plankton

Yesterday was my first day of sampling on the cruise and it was a success. While we waited for the CTD rosette to come to the surface with my first set of samples, we decided to do the first naupliar-net tow. 

When the net came back to the surface, it didn’t seem like we had captured much material. But then we took a look at the collection reservoir, the “cod end”, which was clogged with thick, gooey yellow-brown plankton. It was so thick that I ended up having a really hard time separating out my nauplii from the rest of the larger plankton in the tow! We got our first look at live plankton on the cruise, and were able to get photos of some of these tiny critters under the microscope. After the net tow, the CTD came up to the surface and I went to work concentrating and collecting nauplii from the Niskin bottle samples. This took a long time, because I concentrate 10 Liters of seawater onto a single filter for each sample, and then repeat this for 4 depth features, with duplicate 10 Liter volumes for each feature.

There was some doubt as to whether 10 Liters would be enough seawater to get the necessary number of nauplii for my analyses. So early this morning I took a few minutes to look at how many nauplii I collected in these samples. Actually this is quite difficult to do on a ship. It requires a strong stomach and intense focus because it can be nauseating to sit at the microscope trying to count the animals in a small petri dish as they swish back and forth under the microscope due to the motion of the ship. Luckily I am quite good at it. As I had hoped, I found that I will have enough critters to do the barcoding analyses I planned, with roughly 40-90 nauplii in each 10 Liter sample.

With Day 1 of nauplii sampling complete, I look forward to seeing how these samples change as we move South, approaching the subtropics.

Copepod nauplii

My research is all about copepod nauplii. These are the early developmental stages of copepods, which can be extremely abundant in the water column because a single adult copepod can lay numerous eggs per day. This abundance means they could be important consumers of small algae in the ocean, or as prey for larger organisms like fish larvae or other invertebrate predators. 

But, because copepod nauplii are nearly impossible to identify to species under a microscope, and are small enough that they are at the boundary between being able to sample with whole seawater and having to concentrate larger volumes of water, they are a challenge to study, and thus we don’t know very much about them. One of my primary goals on this voyage is to use targeted sampling with a CTD Niskin rosette to look at whether nauplii are concentrated at particular features within the water column. A CTD Niskin rosette is a common oceanographic tool that allows us to see how physical and chemical parameters of the water column like seawater temperature, salinity, or pH vary with depth or location in the ocean, and holds a ring of sampling bottles that we can close at particular depths and bring to the surface to analyze. To date there has been little description of naupliar depth distributions in the open ocean, and very little is known regarding species-specific distribution patterns. I am targeting my sampling on several features of the upper water column. For example, I am sampling in the upper region of the water column that is well-mixed by wind stress on the surface ocean, called the “mixed layer”, and also at the “deep chlorophyll maximum”, or a layer that includes the highest chlorophyll concentrations in the water column (within phytoplankton cells). 

A second goal is to look at whether particular species or developmental stages of nauplii concentrate within these water column features using DNA barcoding methods to identify nauplii to species. In addition to the CTD samples, I am also collecting nauplii with a very fine mesh net, with a pore size of 0.06 mm in the upper 200 meters of the water column. These samples will allow me to have more nauplii to work with, to compare to my CTD collections (for nauplii) and to our sampling of the adult copepod populations (with a bongo net).

We’re off!

We finally left the dock at Immingham last evening, and its wonderful to finally be at sea. Immingham feels a bit like the industrial armpit of England, with the view around the research vessel James Clark Ross dominated by oil refinery smokestacks and enormous cranes for loading containers onto ships. In port, the smell of oil and gas pervades the air and seemed to stick to your skin, and I had the distinct impression that spending a lot of time in that place would shorten my lifespan. It feels good to be out in the clean air of the North Sea, with the sun penetrating through the clouds and shining on the surface of the sea. We cannot see land, even though we know it is there, due to the cloak of fog that hangs over the coastline. There are a few other boats on the water, not many, and its feel that we are quite alone. We sail now towards Portsmouth, where we will stop for a morning to take on more ship’s oil, before finally heading out over the continental shelf and off into the open sea. Finally! We are off on our adventure. Everyone is ready to begin. We have been in port in Immingham since Sept 18 (for 4 days), working on ‘mobilization’, as the Brits call it. The science party has been loading gear, setting up and testing their instruments, and plumbing seawater lines into incubators for experiments while at sea. The science party is a diverse group this time, both in terms of our countries of origin, and also in terms of our scientific interests. We have scientists working on topics ranging from atmospheric chemistry, measuring fluxes of gases across the air-sea interface, to studies of picoplankton abundance and distribution across the ocean, as these are globally-important, but tiny phytoplankton, as well as our ‘zooplankton group’ that will collect planktonic animals for population genomic studies and also run some experiments while at sea. Many, but not all, scientists on board are part of a long time series program, the Atlantic Meridional Transect Programme, that aims to track changing ocean biogeochemistry on interannual and interdecadal time scales. Several of these scientists have been to sea on this cruise every year for the past 5-10 years, or even more. They are old hands at this work, and are very familiar with the ecology of this region of the global ocean. They are a good group to work with. I am excited to be here, and am looking forward to getting started.