Investigating the lives of one-clawed lobsters

Summer days in Nahant at Northeastern’s Marine Science Center can be hot, and Kelsey Schultz knows that better than most. Schultz spends many sweltering days under the sun at the tank farm, now running her second summer of experiments with Professors Jonathan Grabowski and Randall Hughes. She is currently the head lab technician for Grabowski’s lab, and will start graduate school with him in the fall.

The tank farm sits next to the greenhouse on the Marine Science Center’s campus, with a view of Boston’s skyline peeking over the horizon. Twenty, six-foot diameter tanks sit in rows of five, and these tanks house the Grabowski Lab’s experiments.

Lobsters are separated before the experiment to prevent fighting.

This summer, the tanks contain two things: lobsters and sculpin. The Grabowski lab is interested in competition in lobsters, especially when there’s a predator around. Lobsters compete for many things, including food, mates, and preferred habitat type. Lobsters prefer to hide out in rocky crevices where they are more protected from predators, rather than in seagrass, which affords some cover, and bare sand.

The lobsters in the grassy habitat “still have some protection,” Schultz says, “but it’s the less preferred habitat.” Compared to in rocky habitats where lobsters can hide away under boulders, Schultz says “you can easily pluck out a lobster” from seagrass. However, they are the most at risk of being eaten in bare habitat.

Competition for these resources can be fierce. Schultz says “lobsters get injured when they compete for habitat. They lose their claws easily and often.” Losing a claw can be devastating. While lobsters have a relatively long lifespan—some species can live up to 50 years—it takes several months for a lost claw to regrow to full size. During those months they’re much more vulnerable to predation and survival becomes much more difficult.

As if a lobster with only one claw didn’t have enough on its plate, other lobsters don’t cut them any slack. In last summer’s experiments, Schultz and her colleagues found that “healthy lobsters roam around the tank and harass the injured lobsters. They’ll kick them out of seagrass, kick them out of rocky habitat.” This leaves an already vulnerable disarmed lobster out in the cold in its scariest habitat: open sand.

Without cover, lobsters are easy targets for predators like cod, sculpin, and striped bass. Recently, another predator has been introduced; the range of Black Sea Bass is expanding northward into the warming waters of the Gulf of Maine, which stretches from Cape Cod to Nova Scotia. Last summer, the researchers wanted to know what effect the presence of predators have on competition, using Black Sea Bass as the predator in their experiments.

 A longhorn sculpin flexes its spiny fins after it was removed from its tank to be measured.

A longhorn sculpin flexes its spiny fins after it was removed from its tank to be measured.

The tanks were set up so that the researchers could see which habitat type lobsters preferred: rocky, seagrass, and bare areas. The lobsters could also ‘smell’ predators in the tank, in this case sculpin, through what are called chemical cues. By analyzing the choices of the lobsters, researchers can understand how the presence of a predator or competing lobster affects which habitats an injured lobster spends its time in.

 Grabowski lab technician Adi Behrens labels small lobsters to help tell them apart during the experiment.

Grabowski lab technician Adi Behrens labels small lobsters to help tell them apart during the experiment.

This year, Schultz is trying sculpin as a predator. Sculpin are bottom fish that are found in many environments including the Gulf of Maine. Among other things, sculpin feed on small lobsters. Their specialized fins act as a defense and help them gain traction on the bottom of the ocean in high currents. The large spines on the fins and around the head of the fish give this species its name: Longhorn Sculpin. Measuring the length of a Longhorn is dangerous; Schultz dons thick gloves for protection from its formidable spines while she handles it. Schultz and the other researchers in the Grabowski lab hope to find out how lobsters react to sculpin, which have long been predators of lobsters in the Gulf of Maine.

Preliminary results show that one-clawed lobsters are at a huge disadvantage, and are easily bullied by the two-clawed competitors. “When a lobster that is already injured is in the bare habitat, it’s at a higher risk of being consumed, which is selecting for the more fit lobsters that can compete.” The results of this year’s experiment will help to fill in the gaps in our knowledge of how one-clawed lobsters fare in the ocean.

For now, Schultz is occupied with building and running this year’s experiment. “The setup has been the most challenging part. With our video cameras, they have to be around 9 feet over the tank to capture the whole tank. Figuring out how to get the camera that high, light the tank, and make sure you can actually see the lobsters has been difficult.”

Learn more about the Grabowski and Hughes labs at their lab websites.

Kelsey Schultz releases a sculpin back into a holding tank.

Biology Professor Javier Apfeld awarded NSF CAREER grant for early career faculty

DSC_2777.jpg
 Graduate student Jodie Norris sterilizes a tool used to sort worms in the Apfeld Lab.

Graduate student Jodie Norris sterilizes a tool used to sort worms in the Apfeld Lab.

For Biology Professor Javier Apfeld, his role as an educator is the best part of the job: “mentoring students and talking to them and brainstorming ideas, that’s the best part of it all. To see the students come to the lab and they’re excited about science, as they … develop their own ideas, it’s so exciting to see them grow, mature, and help direct them on their paths and teach good practices of how to be a scientist. To be on a quest for knowledge together is great.” In just three years, Apfeld has hosted over a dozen undergraduates students in his lab, including one co-op. To Apfeld, the undergraduates are an essential part of the lab.

 

 A student in the Apfeld Lab maintains petri dishes that contain C. elegans worms.

A student in the Apfeld Lab maintains petri dishes that contain C. elegans worms.

This year, Apfeld received the 2018 National Science Foundation’s prestigious Faculty Early Career Program (CAREER) award to support his lab’s research on how inter-tissue communication affects protein oxidation during aging. A Northeastern professor for almost three years, Apfeld says the award is “a great honor, it’s nice to be recognized by your peers for this prestigious award.” The CAREER award is intended to support early-career faculty who are poised to become role models in education and research in their department or organization.

One reason undergraduates are such a key part of the lab is the literal millions of worms they help maintain. The Apfeld lab studies aging in C. elegans, a nematode worm and common model organism that allows scientists to study many phenomena in a simpler setting. “Worms only live a couple weeks, we live a thousand times longer,” said Apfeld, though the genetics of aging are surprisingly consistent across many organisms. According to Apfeld, “the same genes that are in worms are in flies and in mice, even though those organisms appear at first to age in different ways.” The worms’ condensed life span allows researchers to study a whole lifetime of the same aging process in just a few weeks, where it may take years in other animals.

 A visualization of oxidation in a C. elegans worm.

A visualization of oxidation in a C. elegans worm.

In the early part of Apfeld’s career, he explored how to quantify and visualize aging in worms. One symptom of aging in tissues is protein oxidation, a form of protein damage. Oxidized proteins accumulate in worms as they age, and fluorescent sensors can pick up oxidation reactions, giving a picture of a worm’s cell as it ages. Research has shown that oxidized proteins are linked to age-related diseases such as cancer, heart disease, diabetes, Alzheimer’s, and Parkinson’s.

Recent research has shown that aging and protein oxidation is controlled by certain genes that tune lifespan and how quickly tissues fail. This means that they not only control how long you life, but how gracefully you may age. Apfeld thinks that these findings ask the biggest questions in the field. “What’s exciting about what we’re studying is that we’re studying the signals from the brain that dictate which tissues should have protein damage, when they should have protein damage, and in other non-NSF projects, the signals controlling the resilience of the animals to stress, and how long they live.” 

 
 Graduate student Jodie Norris sorts C. elegans worms in the Apfeld Lab.

Graduate student Jodie Norris sorts C. elegans worms in the Apfeld Lab.

Apfeld thinks that that the brain seems to be making decisions about when to age, which he says is surprising in an organism whose brain is a paltry 302 neurons, compared to a human’s 100 billion. Apfeld described the brain’s involvement in aging, “the worm is sensing the environment and then thinking about the external and internal environment of the worm and then it’s making a decision of, OK I should live long, I should have high stress resistance, I should have little protein damage, or the other way around.” Determining how sensory input affects the way a worm ages is the first of many questions Apfeld hopes to answer, though the youth of the field leads to uncertainty, as Apfeld confessed, eagerly, “we don’t even know the universe of questions to ask yet.”

The NSF CAREER grant will help fund further research into this area, supporting two graduate students and a co-op every year.

Learn more about the Apfeld Lab’s research on their website.

 

 Stacked petri dishes in the Apfeld Lab.

Stacked petri dishes in the Apfeld Lab.

Using drones to model climate survivors in Downeast Maine

 Undergraduate researcher Sahana Simonetti and Senior Lab Technician Francis Choi conduct a biodiversity survey in Winter Harbor, Maine.

Undergraduate researcher Sahana Simonetti and Senior Lab Technician Francis Choi conduct a biodiversity survey in Winter Harbor, Maine.

Anyone who has spent a day at a New England beach knows that it is often colder on the coast, and may have regretted not packing a sweater with their bathing suit and flip flops. Compared to the chilly air, the water can be even colder still, sometimes shockingly so. Like a beachgoer jumping in and out of the water, intertidal animals such as a mussel on the rocks experience a roller coaster of temperatures over a day. The tides bring cold, food-filled water twice a day only to pull it away again to reveal the mussels to punishing heat of the summer sun.

What a beachgoer may not realize is that mussels living on different beaches or even different rocks on the same shore can live in climates as different as a Boston suburb and a Cape Cod beach.  Underdressed tourists aren’t the only ones caught by surprise by local differences in environment; large amounts of research in marine biology neglect local variability, instead focusing on large scale environmental factors.

DSC_1072.jpg

Researchers from the Helmuth lab at Northeastern piled into two cars and made the 6 hour, 350 mile drive to Downeast Maine to explore local variability in the field. The crew for this trip included Dr. Brian Helmuth, the primary investigator and head of the Helmuth Lab, senior lab technician Francis Choi, two graduate students — Jessica Torossian and Ashley Cryan— and four undergraduate students, Sahana Simonetti, Sophia Ly, Jaxon Derow, and myself. The Helmuth Lab is focused on identifying and forecasting factors that are changing with the Earth’s climate.

Predicting a mussel’s response to a widespread effect like global temperature rise can be tricky, as seemingly small changes in its environment can have radical effects. Shading by algae or a rock, insulation from fellow mussels or mud, or even the orientation of the mussel can all influence how heat or cold impact the mussel. Shaded areas can be up to 60°F cooler than an area just 6 inches away.

 Blue mussels and common periwinkles are crammed into a crack in the rocks in Winter Harbor, Maine. Refugia like this crack may allow these organisms to weather extreme climate events.

Blue mussels and common periwinkles are crammed into a crack in the rocks in Winter Harbor, Maine. Refugia like this crack may allow these organisms to weather extreme climate events.

The local environment transforms an enormous number of life-determining factors for a mussel: wave action or ice scouring individuals off of rocks, breezes cooling their shells, small currents between rocks changing food availability, the list goes on and on. Expand these effects to every organism in the intertidal (the area between the water line at high and low tides), and you’ve got your mind wrapped around the importance of such small differences. New research has shown that local variability can buffer extreme events like heat waves or cold snaps, as insulated areas become a refugium from stress, safeguarding groups of survivors. A refugium is a biological term that refers to an area that supports a population of a once wider spread species. These survivors act as a backup, replenishing the surrounding areas with life after a large mortality event.

Until now, large scale studies were limited in their analyses, unable to take into account or ignoring local effects in an ecosystem. As strong storms and intense weather events grow more frequent, more extreme, and more persistent due to climate change, the ability to quantify the importance of local effects is poised to become a key focus of restoration and conservation efforts, helping damaged populations recover. 

 Helmuth Lab graduate student Jessica Torossian measures percent cover of algae — how much of the rock surface is covered by each species — during a biodiversity survey in Hamilton, Maine.

Helmuth Lab graduate student Jessica Torossian measures percent cover of algae — how much of the rock surface is covered by each species — during a biodiversity survey in Hamilton, Maine.

As the sun rose on Downeast Maine in mid May, the researchers of the Helmuth lab and I were already packing the van full of field gear including full rain gear, several drills, precise GPS location hardware, a drone, and 8 pairs of knee high boots. Traveling light is not in a scientist’s vocabulary.

Why Maine? Well, the intertidal in the Gulf of Maine is a very stressful place for organisms to live, with strong summer and winter storms, intense temperature swings over the year and between air and water, not to mention that the Gulf of Maine is one of the fastest warming bodies of water in the world. The Helmuth lab has also partnered with Haifa University in Israel to study a sister body of water, the Eastern Mediterranean, which is warming at a similarly alarming rate.

 Francis Choi flies a drone to map the intertidal landscape during a 2017 field expedition.

Francis Choi flies a drone to map the intertidal landscape during a 2017 field expedition.

We arose so early in order to catch the morning low tide, allowing us to work for several hours in the morning and again later in the day as the tide receded. The first step at a new site was to establish the two transects: 25-meter lines that would represent our research area. Along these lines we fastened permanent research areas which are marked by bolts drilled into the rock. Researchers return to these same sites months or years later to observe changes in the marine life, especially after extreme weather events. The main way that the Helmuth lab is assessing marine life is through measurements of biodiversity, or the amount of life and number of species in an area. The working theory is that more complex areas, which contain more refugia, will support higher levels of biodiversity.

To map the complexity of the intertidal, the Helmuth lab uses a novel technique. The lab creates 3D models which are then combined with thermal data, giving the researchers a detailed view of the environment and where organisms hunker down during extreme weather events. Drones are the key to creating these models. At each site, a drone flies in a grid pattern while taking photos and videos. Data from the drone’s positioning system is combined with GPS coordinates from measurements on the ground, providing a precise rendering of the research area accurate to the centimeter. All of this data is integrated into a rich 3D model back in the lab.

The Helmuth Lab is collaborating with Dr. Tarik Gouhier’s lab, to build another kind of model from their data. The Gouhier Lab uses mathematical models to determine how ecology on different scales interacts. Together, the labs are seeking to create a model that can predict the effects of refugia and apply the knowledge to large scale ecological processes and effects such as the temperature of a whole gulf, or the entire eastern seaboard. In the future, this model will be able to help researchers better understand the intricate dynamics of intertidal life.

The researchers hope that their model and data will help to encourage others to not overlook the importance of local effects, so that the effects of climate change can be more carefully and successfully managed.

To learn more about the Helmuth Lab and their research, visit their website.

 The sun sets at the West Quoddy Lifesaving Station, a former Coast Guard operation that served as the base of the Helmuth Lab for the first half of the trip.

The sun sets at the West Quoddy Lifesaving Station, a former Coast Guard operation that served as the base of the Helmuth Lab for the first half of the trip.