Field work

[New Publication] MEPS publishes Julie’s Ms research on silverside otoliths

12 December 2019. We are happy to announce that Marine Ecology Progress Series just published our latest paper on Atlantic silversides, but this time not an experimental but a field study! During her time in our lab, Julie Pringle investigated the otolith microstructure of young-of-year silversides, finding intriguing patterns about differential growth in males and females that likely result in sex-selective survival during their growing season. Congratulations, Julie, well done!


Pringle, J.W. and Baumann, H. (2019) Otolith-based growth reconstructions in young-of-year Atlantic silversides (Menidia menidia) and their implications for sex-selective survival. Marine Ecology Progress Series 632:193-204


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This graph shows reconstructed hatch distributions of male and female Atlantic silversides sampled in fall 2015. Counting daily otolith increments, young-of-year fish caught in October could be reliably aged, whereas those from November and December where likely underaged because water temperatures had already decreased below their growth threshold. This graph compbines previous knowledge, environmental monitoring and results of otolith microstructure analysis.

From the abstract:

“We examined the utility of otolith microstructure analysis in young-of-year (YoY) Atlantic silversides Menidia menidia, an important annual forage fish species along the North American Atlantic coast. We first compared the known hatch window of a local population (Long Island Sound, USA) to otolith-derived hatch distributions, finding that YoY collected in October were reliably aged whereas survivors from November and December were progressively under- aged, likely due to the onset of winter ring formation. In all collections, males outnumbered fe- males, and both sexes had bimodal size distributions. However, while small and large females were almost evenly represented (~60 and ~40%, respectively), over 94% of all males belonged to the small size group. We then examined increment widths as proxies for somatic growth, which suggested that bimodal size distributions resulted from 2 distinct slow- and fast-growing YoY phe- notypes. Length back-calculations of October YoY confirmed this, because fast- and slow-growing phenotypes arose within common bi-weekly hatch intervals. We concluded that the partial sexual size dimorphism in this population resulted largely from sex-specific growth differences and not primarily from earlier female than male hatch dates, as predicted by the well-studied phenome- non of temperature-dependent sex determination (TSD) in this species. Furthermore, observed sex ratios were considerably less male-biased than reconstructed thermal histories and published laboratory TSD values predicted. Assuming that selective mortality is generally biased against slower growing individuals, this process would predominantly remove male silversides from the population and explain the more balanced sex ratios at the end of the growing season.”


[New Publication] Conservation Physiology publishes our first sand lance paper!

21 November 2019. We are excited to announce the Chris Murray‘s paper on the unusual, high sensitivity of early life Northern sand lance to acidification and warming has just been published in the journal of Conservation Physiology! This is the first publication of our extensive work on this enigmatic species.

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Sand lance species play a key ecological role in most temperate to polar shelf ecosystems of the northern hemisphere, but they have remained unstudied with respect to their sensitivity to predicted future CO2 levels in the ocean. For the past three years (2016 – 2018), we have sampled and spawned with northern sand lance (Ammodytes dubius) from Stellwagen Bank National Marine Sanctuary and subsequently reared their embryos under factorial CO2 x temperature conditions to hatch and early larval stages. Our results were striking, in all years, high CO2 conditions severely reduced embryo survival up to 20-fold over controls, with strong synergistic reductions under combined high CO2 and temperature conditions. High CO2 also delayed hatching, reduced remaining endogenous energy reserves at hatch, and in combination with higher temperatures, reduced embryonic growth.

Indeed, given the observed effect sizes, northern sand lance might be the most CO2 sensitive fish species tested to date.


[Lab News] Chris Murray starts his post-doc at University of Washington

Chris-Murray

15 August 2019. The Baumann lab is happy to announce that Chris Murray has started his new chapter of life and science at the west coast with the University of Washington. Congrats Chris, we know you will do great!

Chris started his PhD at UConn/Avery Point in September 2014, after finishing his MS in May 2014 at Stony Brook University, NY. While building on his experience in ocean acidification research, for his PhD he studyied multi-stressor effects of OA and hypoxia on coastal marine fishes. He had an outstanding part in designing and building our factorial larval rearing system ("Larval city") in UConn Rankin Seawater lab. The system allows up to nine independent, static or fluctuating CO2 x O2 environments simultaneously. It has been in full use during spring and summer months of the past four years.

After a phenomenally dedicated four years, Chris defended his PhD in December 2018 and recently graduated with this PhD from UConn.

His thesis titled An experimental evaluation of the sensitivity of coastal marine fishers acidification, hypoxia, and warming

is publicly available at the OpenCommons Site of the UConn Library.


Four recent publications of Chris:


Check out some footage of Chris and his lab mates over the years below!

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

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!

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


Baumann-etal-BiolLett2018---Fig01
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!

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!


Mackenzie-Blanusa
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

Stellwagen whales
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

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

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!