Author: Hannes Baumann

[Research news] A day at Harvards MCZ

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Friday, 8 June 2018. Hannes and Maria traveled to Boston’s Harvard University to meet with Valentina di Santo from the Lauder Lab at the Museum for Comparative Zoology. Thanks to our collaborators there, we were able to use a 2D-digital X-ray machine there, which we needed to complete the next big step in our Menidia Gene project.
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Genetic & body samples went in different vials
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Maria Akopyan processing the fish after x-raying
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Maria and Valentina in the shark section of the collection
A few weeks ago, Maria had already measured each individual fish's length, weight, shape, routine metabolism, and maximum sustained swim speed. The next trait we're keen on mapping quantitatively to the silverside genome is the number of vertebrae, which we know increases in wild populations from south to north. What will our South/North hybrid F2 generation show?
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At the Lauder lab, ‘lunch together’ is common thing
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The famous Latimeria from the collection
Thanks to Valentina's excellent help, the work went without a hitch. At the end, we even had some spare time to enjoy the great atmosphere int the Lauder Lab during lunchtime, the tour through various lab installations, the experimental fish, and even the adjacent Harvard Zoological museum. Thank you all for the fun day at Harvard!
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Settings used for x-raying juvenile silversides
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Hannes and Valentina in the x-ray room
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George Lauder adjusting equipment in the swim lab

The 282 fish are now split in a DNA sample for extraction and a body sample for further trait measurements.

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[Lab news] The old swim flume coming back to life

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4 April 2018. Today, Adelle Molina and Teresa Schwemmer from the Nye Lab at Stony Brook University visited us with a bunch of respirometry equipment in tow. We were trying to find out how to measure critical swimming speeds and oxygen consumption on individual silverside juveniles. This information, along with other individual traits such as growth, lipid content, and vertebral number will later be used in our new NSF-project examining the genetic underpinnings of local adaptation in this species.
One crucial piece of equipment to do this work is a swimming chamber, also called swim flume. The one we will use is almost 20 years old and has already been used for silverside work more than a decade ago. After a long odyssey through several labs and institutions in the US, we finally got hold of it again, gave it some serious TLC and now hope to resurrect it. Thanks to our pro’s from Stony Brook, the first tests were promising today! Thank you Adelle and Teresa.

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A ~ 3 cm juvenile silverside swimming against the induced current in the swim tunnel
Swim chamber
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An old lady, but still shiny and good to go!
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Adelle and Teresa in the Rankin Lab

[New publication] No CO2 effects on silverside starvation

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31 March 2018. We’re happy to announce that Marine Biology just published our latest study examining the starvation tolerance of silverside larvae and juveniles at contrasting CO2 conditions. We compiled observations from five separate experiments spanning different years, laboratories, temperatures, life stages, and CO2 levels. Contrary to expectation, we found that starvation rates were largely independent of the CO2 environment in this fish species.

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One major set of data was produced by Elle Parks as part of her Research Experience for Undergraduates (NSF-REU) in summer 2017. Well done, everybody!

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Hannes shows Elle Parks (REU 2017), how individual screen with enumerated embryos are suspended into the replicate rearing containers. (Photo: Peter Morenus, UConn)
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On 9 June, Elle and Julie strip-spawn Atlantic silverside females into spawning dishes covered in window screen for eggs to attach. (Photo: Peter Morenus, UConn)
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M. menidia. (A) Relative cumulative starvation mortalities of early juveniles reared under ambient (grey line, diamonds) vs. high CO2 conditions (black line, circles). Symbols depict individual replicates, lines represent treatment means. (B) Total length of juveniles perishing during the experiment at ambient (grey diamonds) vs. high CO2 conditions (black circles). Lines represent the median(solid lines), 5th and 95th percentiles (dashed lines) of TL estimated with locally weighted, non-parametric density estimators. The initial TL distribution at the beginning of the experiment is depicted on day 0 as the median (white circle), 5th/95th percentiles (whiskers) and the minimum and maximum (white stars).

[Research news] Silversides in a CT scanner

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26 March 2018. Today we got our first glimpse of an incredible new way of imaging the inner calcified structures of a fish body, particularly the ear bones (otoliths), of which every teleost fish has six, three on each side inside the skull. Otoliths are long known to fish ecologists for their properties to record and store information about a fish’s age, growth and habitat. With an adult Atlantic silverside, Hannes visited John Shepherd, facilities scientist and member of the Goldhamer lab at UConn, Storrs (Biology Physics Building), who showed us the use of a new, state-of-the-art micro CT-scanner (IVIS). Turns out, the system effortlessly imaged all six otoliths inside of the fish’s head. Later in the year, we will use the technique to image silversides reared at contrasting CO2 conditions to see whether they differ in their otolith size, volume, and structure. Thank you, John, for this truly inspiring demonstration!

CTscan Menidia
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[New publication] Brachiopods resilient to global change

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Congratulations to Emma Cross to her new publication in Global Change Biology today!

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The common brachiopod Calloria inconspicua (pink shells) in their natural environment in New Zealand. Photo credit: Dr Liz Harper.
Her study that was part of her PhD-research concludes that the brachiopod Calloria inconspicua, a common seafloor dwelling marine invertebrate from New Zealand, is more resilient to environmental change than expected.

Read the full press release by the British Antarctic Survey

[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

Anna-Tigano

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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[Lab news] Baumann lab at OSM2018 and the OA-PI meeting

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OSM2018
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Members of the Baumann lab attended two back-to-back meetings in Portland, OR, in February. From 11-16 February, we participated in 2018 Ocean Sciences Meeting, while from 17-19 February we all took part in the 4th Ocean Acidification Principal Investigators meeting.
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Holding the fort at the Rankin lab were Julie and Charles, who did an excellent job. Thank you guys!
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At OSM, Hannes chaired a large session (OC51, OC52) titled “Multiple Stressors and Multiple Disciplines: Understanding the Consequences of Global Ocean Change for Marine Species” together with colleagues from Bermuda Institute of Ocean Sciences (BIOS, Amy Maas), the Virgina Institute of Marine Sciences (VIMS, Emily Rivest), and the University of South Carolina (Catherine Davis). The line-up of speakers was impressive and included our very own Emma Cross (speaking on brachiopod resistance to CO2) and Hans Dam (presenting our findings of multigenerational CO2 effects on the copepod Acartia tonsa).

At the OA PI meeting, Hannes gave an summary talk of key advances in the field of experimental OA approaches, while all of us worked in small synthesis groups on synthesizing products and projects.

Portland, albeit rainy, was as usual a great city to come to.

OSM2018 sessions OC51, OC52 (Baumann, Maas, Rivest, Davis)
Multiple Stressors and Multiple Disciplines: Understanding the Consequences of Global Ocean Change for Marine Species

    Session 1

  • Zimmerman et al. Modeling the Impacts of Water Quality and Climate Change on Submerged Aquatic Vegetation in the Chesapeake Bay
  • Frieder et al. Advancements in Quantifying Energy Costs for Organisms to Respond to Ocean Change
  • Hofmann et al. Who’s Your Mommy? Transgenerational Effects in Purple Sea Urchins from Nearshore Kelp Forests in California
  • Waldbusser et al. Understanding the multi-stressor impacts of ocean acidification on marine calcifiers: What controls biocalcification? Saturation state or substrate inhibitor ratio
  • Silbiger et al. Nutrient addition disrupts dependence of calcification on aragonite saturation state
  • Cross et al. A 120-year record of resilience to environmental change in brachiopods
  • Dam et al. The copepod Acartia tonsa in a greenhouse world: Transgenerational plasticity of life history traits
  • McLaskey et al. Ocean Acidification Driven Changes to Food Quality are Transferred Unpredictably Across Trophic Levels
    Session 2

  • Palmer et al. Recent Fossil Record Provides Unique Insight into Impacts of Multiple Stressors on Community Ecology
  • Krumhardt et al. Coccolithophore growth and calcification under future oceanic conditions
  • Rivest et al. Multiple stressors elicit unique responses in animal and algal partners: the potential for physiological plasticity in symbiotic coral larvae under global ocean change
  • Cornwall et al. Impacts of pH Variability and Past pH History on Coral and Coralline Algal Calcification: a Mechanistic and Multi-generational Approach
  • Eagle et al. Combining microelectrode and geochemical approaches to study the impact of pCO2 and temperature changes on the internal pH and carbonate chemistry of corals and their relation to growth responses
  • Weinnig et al. Physiological Response of a Cold-Water Coral (Lophelia pertusa) to the Combined Stressors of Climate Change and Hydrocarbon Influence
  • Bednarsek et al. Interactive effects of temperature and acidification on pteropod distributions in the California Current Large Marine Ecosystem
  • Davis et al. Juvenile Rockfish Recruits Show Resilience to CO2-Acidification and Hypoxia across Biological Scales

[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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