Field work

[Lab news] Deanna Elliott completes her NSF-REU project

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10 August 2019. Deanna Elliott from Arizona State University has just successfully completed her summer research project as our third NSF-REU student. For her REU-project she reared Atlantic silverside larvae under different feeding regimes to create fish of different body sizes and then analyzed them for trace levels of mercury in their tissue. She tested the hypothesis that mercury concentrations in fish can be used as a proxy for ingestion rates, which are important to trophic ecosystem models to perform better.

Here’s what Deanna had to say about her REU research experience:

This summer, I spent 10 weeks in the Baumann Evolutionary Fish Ecology lab and had a blast! The entire lab was incredibly welcoming, and made me feel at home immediately. We jumped right into my project and I had so many new experiences, it was almost overwhelming. We went seining for silversides in Mumford Cove, fertilized fish eggs… I became a Fish Mommy for the first time, rearing approximately 500 juvenile silversides for five weeks—I had never even had a fish tank before! I also got valuable experience in the chemistry lab, analyzing the mercury content of my Fish Babies. I felt very welcomed and received a lot of encouragement on my project and the presentation I had to give at the end of the program. Hannes and Zosia especially made me feel appreciated and supported, and that made all the difference in my experience with UCONN’s marine biology REU.

Check out some of the impressions from Deanna’s time at UConn. Great job, Deanna!

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[Lab news] NSF-REU student Deanna Elliott joins the Baumann lab

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Deanna Elliott is a junior at Arizona State University who has joined the Baumann lab in summer 2019 as our third NSF-REU student. Deanna has experimented with locusts before, but now strives to become an expert fish rearer. Her project will rear Atlantic silverside larvae under different feeding regimes to create fish of different body sizes and then analyze the these fish for trace levels of mercury in their tissue. She will test the hypothesis that mercury concentrations in fish can be used as a proxy for ingestion rates, which are important to improve trophic ecosystem models. Welcome, Deanna!

[Atlantic silverside, Menidia menidia, mercury, ingestion rates]
dbellio2@asu.edu

An early brainstorming sketch on the whiteboard, outlining Deanna’s REU experiment
Fertilizing
Deanna starts her REU experiment by fertilizing strip-spawned silverside eggs

[Publication] Meta-analysis of silverside CO2 experiments published!

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28 November 2018. Hannes, Emma, and Chris are happy to announce that Biology Letters just published our latest study, a meta-analysis of 20 standard CO2 exposure experiments conducted on Atlantic silverside offspring between 2012-2017. All these years of sustained experimental work resulted in the most robustly constrained estimates of overall CO2 effect sizes for a marine organism to date.
The study demonstrated:

  • A general tolerance of Atlantic silverside early life stages to pCO2 levels of ~2,000 µatm
  • A significant overall CO2 induced reduction of embryo and overall survival by -9% and -13%, respectively
  • The seasonal change in early life CO2 sensitivity in this species
  • The value of serial experimentation to detect and robustly estimate CO2 effects in marine organisms

Baumann, H., Cross, E.L., and Murray, C.S. Robust quantification of fish early life CO2 sensitivities via serial experimentation. Biology Letters 14:20180408

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This figure shows the summary of early life responses to high CO2 conditions in Atlantic silversides across all experiments conducted between 2012-2017. Effect size was estimated using the log-transformed response ratio (A-D). Error bars are 95% confidence intervals. The responses are considered significant if the confidence interval does not include zero. Panels E-F: seasonal decomposition of response ratios, showing that silverside early life stages are most sensitive to high CO2 at the beginning and end of their spawning season.

[Research news] Sandlance are spawning on Stellwagen Bank again!

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15 November 2018. After a stretch of foul weather kept us from going out to Stellwagen Bank last week, this time all the stars aligned for Emma and Mackenzie. Due to their success in catching spawning ripe Northern sandlance, we are now embarking on our third year of CO2 x temperature experiments on this species!

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Here is how Mackenzie Blanusa experienced her first trip to these enigmatic waters:
“This particular sandlance cruise was a day filled with firsts and is definitely a trip to remember. I accompanied Emma, Hannes’ postdoc, up to Scituate the night before the cruise and was given a rundown of what needed to be accomplished. I was a bit overwhelmed at first, because I’ve never dealt with sandlances before and did not know a lot about these fish. Nevertheless, I was eager to learn something new and was ready to help out wherever needed.

The goal of the sandlance cruise was to collect running ripe males and females to do a fertilization via strip spawning. Emma and I were a bit doubtful at first because we got less than 10 sandlance on the first two trolls. However, things got much better by the afternoon, and our most successful trawl caught 147 sand lance. I helped out with the fertilization and deploying the trawl, two things I have never done before. The most exciting part of the day was getting to see humpback whales. Usually they are in the distance but today they were right next to the boat. Everyone on board said that this never happens and it was very unusual so I felt very lucky to have seen whales at such a close proximity.”

Overall, the trip was a huge success and it was very refreshing to see everything go as planned. The only downside to the day was driving back home through a snowstorm. I later found out that there was a 73% fertilization success and we got 27,000 embryos for Emma’s experiment. I am very grateful to have gotten the opportunity to help out on this sampling cruise and am looking forward to doing this again in the future!

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Emma on the makeshift spawning station for sand lance on board the RV Auk
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Mackenzie strip-spawning sand lance on the ship
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Added perks of doing research on Stellwagen Bank …
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Exactly 0.5ml of sand lance eggs (~ 600) were distributed into each replicate per treatment
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Emma and Julie pipetting sand lance eggs

[Lab news] Baumann & Therkildsen lab on a silverside road trip

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28 October 2018. Members of the Therkildsen (Nina Therkildsen, Maria Akopyan) and Baumann labs (Hannes Baumann, Callie Concannon) went on a joint road trip together to sample juvenile Atlantic silversides for our NSF project about the genomic underpinnings of local adaptation in the ocean. We targeted again three sites, Morehead City NC, Oregon Inlet NC, and Chincoteague Island VA, sampling silversides via beach seine. The weather was lousy and the work strenuous, but the mood elated, because we got all the fish we needed for subsequent genomic and otolith analyses.
What a great collaboration. Check out some of the pictures from the trip below.

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[Lab news] Baumann lab participates in first DMS sea course

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12 October 2018. This year, the Department of Marine Sciences at UConn Avery Point has conducted his first graduate course on physical and biological oceanographic methods, which culminated in a two day research cruise aboard the newly stretched R/V Connecticut. The cruise sampled stations from Eastern Long Island Sound all the way out the continental shelf, deploying CTD’s, sediment corers and grabs, as well as zooplankton and nekton nets. Callie and Hannes from the Baumann lab were part of the fun!

Check out some of the action in the youtube clip below.

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f.l.t.r.: Alec Shub, Michael Mathuri, Hannes Baumann, Samantha Siedlecki, James O’Donnell, James DeMayo, Amin Ilia, Callie Concannon, Molly James
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[Lab news] Video of Mumford Cove probe swap

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14 June 2018. Members of the Baumann and Mason lab went on a trip to Mumford Cove, today, and Chris Tsang went along with his GoPro. Thanks to Charlie, the skipper, the ride was smooth and a pleasure, a swapping our pH, Temperature, oxygen, and salinity sensor was successfully swapped with a new one recording for the next weeks in 30 minute intervals. Wes Hoffman from the Mason lab, collected zooplankton with a Bongo-net. Sydney Stark, our NSF-REU student this summer, came along just for the fun.

See the fun for yourself!

[Research news] New NSF grant to study silverside genes!

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We are overjoyed to announce that NSF is funding a new and collaborative research project to look at the genomic underpinning of local adaptation in the Atlantic silverside! Check out below for a first glimpse of the project website.

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NSF-OCE #1756751 The genomic underpinnings of local adaptation despite gene flow along a coastal environmental cline (2018-2021)

Principal investigators

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Nina Therkildsen (Cornell)

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Hannes Baumann (UConn)

Post-docs

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Anna Tigano (Cornell)

Graduate students

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Maria Akopyan, Callie Concannon

Collaborators

Aryn-Wilder

Aryn Pearce-Wilder

Oceans are large, open habitats, where it was previously believed that the lack of obvious barriers to dispersal would result in extensive mixing, thereby preventing organisms from adapting genetically to particular habitats. It has recently become clear, however, that many marine species are subdivided into multiple populations that have evolved to thrive best under contrasting local environmental conditions. Nevertheless, we still know very little about the genomic mechanisms that enable divergent adaptations in the face of ongoing intermixing.

Learn more …

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This project focuses on the Atlantic silverside (Menidia menidia), a small estuarine fish that exhibits a remarkable degree of local adaptation in growth rates and a suite of other traits tightly associated with a climatic gradient across latitudes. Decades of prior lab and field studies have made M. menidia one of the marine species for which we have the best understanding of evolutionary tradeoffs among traits and drivers of selection causing adaptive divergence. Yet, the underlying genomic basis is so far completely unknown.We will integrate whole genome sequencing data from wild fish sampled across the distribution range with breeding experiments in the laboratory to decipher these genomic underpinnings. This will provide one of the most comprehensive assessments of the genomic basis for local adaptation in the oceans to date, thereby generating insights that are urgently needed for better predictions about how species can respond to rapid environmental change. The project will provide interdisciplinary training for a postdoc as well as two graduate and several undergraduate students from underrepresented minorities. The findings will also be leveraged to develop engaging teaching and outreach materials (e.g. a video documentary and popular science articles) to promote a better understanding of ecology, evolution, and local adaptation among science students and the general public.

The project is organized into four interconnected components

Part 1 examines fine-scale spatial patterns of genomic differentiation along the cline to a) characterize the connectivity landscape, b) identify genomic regions under divergent selection, and c) deduce potential drivers and targets of selection by examining how allele frequencies vary in relation to environmental factors and biogeographic features.
Part 2 maps key locally adapted traits to the genome to dissect their underlying genomic basis.
Part 3 integrates patterns of variation in the wild (part 1) and the mapping of traits under controlled conditions (part 2) to a) examine how genomic architectures underlying local adaptation vary across gene flow regimes and b) elucidating the potential role of chromosomal rearrangements and other tight linkage among adaptive alleles in facilitating adaptation.
Part 4 examines dispersal – selection dynamics over seasonal time scales to a) infer how selection against migrants and their offspring maintains local adaptation despite homogenizing connectivity and b) validate candidate loci for local adaptation.

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[Research feature] Our multistressor NSF project in the spotlight

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This research feature makes the case for multistressor research to a broad general audience and introduces our NSF project and its participants. Download the feature by clicking on the pictures or the link below.

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Download the Research feature
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