Ocean Acidification

[Lab news] Baumann lab attends the Larval Fish Conference in Victoria


Holding the fort at the Rankin lab were Emma and Sydney, who did an excellent job. Thank you guys!

The Delta Victoria Ocean Pointe Resort was the conference venue

Before the conference, we all attended a workshop on larval fish identification

Whale-watching with Corinne, Julie & Chris
Here is how Julie experienced her first LFC:

Ever since attending the American Fisheries Society conference in 2014, I’ve wanted to go to another fish-focused conference. I was lucky enough to attend the 42nd annual Larval Fish Conference this year in Victoria, British Columbia, and it surpassed all my expectations. The week started off with a larval fish identification workshop where we got to learn techniques from renowned larval fish experts (and see some really cool fish larvae!). The talks were impressive and thought-provoking, providing many new ideas for research and how to give an engaging talk. My favorite part was meeting all the larval fish ecologists whose publications I’ve been reading for my thesis. I spent most of my evenings exploring Victoria with other grad students attending the conference and left with many new friends from institutes all over the world! The trip ended with a whale watch, where we saw a pod of 5 Orcas. Overall, the Larval Fish Conference was a great experience that I hope to someday attend again!

Oral presentations:

  • Pringle, J. and Baumann, H. Sex-specific growth and mortality patterns in juvenile Atlantic silversides (Menidia menidia) from Connecticut waters. Talk. 42nd Larval Fish Conference, Victoria, BC, Canada 24-28 June 2018
  • Murray, C.S., Wiley, D., and Baumann, H. Early life stages of the northern sand lance Ammodytes dubius show high sensitivity to acidification and warming in a CO2 × temperature factorial experiment. Talk. 42nd Larval Fish Conference, Victoria, BC, Canada 24-28 June 2018

Water taxi in Victoria

Old Victoria
Beyond this point …
Orca whale
Harbor front with Parliament building
Local celebrity, the one eyed seal

[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!

[New publication] No CO2 effects on silverside starvation

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.

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!

Hannes shows Elle Parks (REU 2017), how individual screen with enumerated embryos are suspended into the replicate rearing containers. (Photo: Peter Morenus, UConn)
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)

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).

[New publication] Brachiopods resilient to global change

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

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

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


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.

Holding the fort at the Rankin lab were Julie and Charles, who did an excellent job. Thank you guys!

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

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.


[Research news] Are sand lance embryos particularly sensitive to high CO2?

This article has been cross-posted at news sites of Connecticut SeaGrant, Stellwagen Bank National Marine Sanctuary, and the Early Life History Section of the American Fisheries Society.

By Hannes Baumann

On this dimly lit November afternoon, rain mercilessly drenched scientists and crew on board the R/V Auk as it slowly navigated the waters of Stellwagen Bank. A world like a wet sponge. Sky and ocean, indistinguishable.

Thanksgiving, the next day.

Despite the circumstances, the team’s mood was nothing short of elated. Our small beam trawl had just spilled hundreds of silvery fish on deck, wriggling like eels. They were Northern sand lance (Ammodytes dubius).

Running ripe adults.


Apparently, they like Thanksgiving, too.


As the ship docked back in the Scituate, Mass., harbor that day, the rain thinned to hazy darkness.

“Let’s get a coffee and then on the road,” mumbled Chris, who led the team, “the real work of the experiments has just begun.”

Chris RV Auk Sediment grab
Chris Murray, a member of the research team, checks the contents of a sediment grab for sand lance. Photo: Jacob Snyder / Red Skies Photography

The RV Auk in early morning, getting ready for another sand lance sampling trip to Stellwagen Bank. Photo: Hannes Baumann
Stellwagen Bank, the National Marine Sanctuary just north of Cape Cod, is a true hotspot for some of the Atlantic Ocean’s most iconic creatures: whales, seals, tuna and seabirds, who all share a particular appetite for this one fish – sand lance. Some experts in the sanctuary’s ecosystem call this species its “backbone.” Others consider it a classic forage fish, responsible for transferring massive amounts of energy from lower to upper levels on the food chain.

Sand lance have a few interesting and rare characteristics. They alternate between schooling and foraging in the upper water column and extended periods of being almost completely buried in sand. For that, they rely on sand of a particular grain size and with very little organic content. It’s the kind of sand that defines large areas of the Stellwagen Bank.

Surprisingly little is known about the ecology and ecosystem importance of this sand lance species, although research on its European relatives (A. tobianus, A. marinus) is more advanced. In particular, experiments on early life stages of Northern sand lance have been lacking, save for some pioneering work on rearing methods of the related A. americanus (Smigielski et al. 1984). One question that was of particular interest to our lab involved the potential sensitivity of this fish species to carbon dioxide (CO2). That’s due to two other interesting and rare characteristics of sand lance. They spawn in late fall and winter in cold (and still cooling) waters, which is why their eggs and larvae develop extremely slow compared to other, more typical spring and summer spawning species. In addition, the species is found not in nearshore, but offshore coastal waters, where smaller seasonal and daily CO2 fluctuations more closely resemble oceanic conditions. Could sand lance offspring be particularly sensitive to higher levels of oceanic carbon dioxide predicted during the next 100 to 300 years as climate change effects intensify?

Sand lance caught on Stellwagen Bank in November 2014
Adult sand lance, shown here, is the favorite food for whales, seals, tuna and seabirds. Photo: Hannes Baumann
Early results suggest that sand lance larva, shown in closeup, are particulary sensitive to higher levels of carbon dioxide. Photo courtesy of Hannes Baumann

Over the past two years (2016-17), we successfully found and sampled spawning ripe sand lance on Stellwagen Bank during a narrow window in late November. Eggs and sperm from adults were removed on board or after being transported live to our laboratory at UConn Avery Point. We reared newly fertilized embryos to hatch and to the feeding larval stage, under different sets of temperature and CO2 conditions, measuring survival and growth traits along the way.

Our experiments are still ongoing, and rearing protocols are being improved.

The preliminary findings, however, are stunning. Survival to hatch was dramatically reduced under elevated and high compared to baseline CO2 conditions. It was severely lowered at higher (10°C or 50°F) compared to lower temperatures (5°C or 41°F). Our second experiment this year appears to repeat this pattern. If these results continue, that would mean sand lance is one of the most CO2-sensitive species studied to date.

General interest in sand lance goes beyond its sensitivity to carbon dioxide. Given the species importance for the ecosystem and coastal economy, there are now increasing efforts to better understand sand lance feeding ecology, distribution and relationship to the rest of the food web. In this regard, funding of our project by the Northeast Sea Grant Consortium proved prescient and a seed for subsequent grants from MIT Sea Grant and the Bureau of Energy Management (BOEM) to continue the work. Surely, the groundswell of interest in sand lance is commensurate with its importance and will enable insights into better management strategies for sensitive ecosystems like those along the U.S. Atlantic coast.

This graphic shows survival to hatch rates of Northern sand lance embryos reared at three carbon dioxide levels and two temperatures. Graphic: Hannes Baumann

Collaborators on this project are: D. Wiley of the National Oceanic and Atmospheric Administration-Stellwagen Bank National Marine Sanctuary; P. Valentine of the U.S. Geological Survey; and S. Gallagher and J. Llopiz, both of the Woods Hole Oceanographic Institution.

[Lab news] Live, feeding sand lance larvae

17 January 2018. Since November 2017, we have ongoing experiments with offspring of Northern sand lance (Ammodytes dubius), a winter-spawning forage fish of ecological importance along the North-American Atlantic coast. The clip below shows larvae almost two months after fertilization, developing nicely in 5C water and feeding actively on live rotifers. The experiments, led by Chris Murray for his PhD research, study the CO2 sensitivity of this species in our factorial larval rearing system. To our knowledge, this is the first time that this particular species has been reared that far under experimental conditions. Have a look!

Feeding sand lance
Sand lance (Ammodytes dubius) larvae feeding in green water on rotifers

[New publication] Mothers matter for the CO2 sensitivity of fish offspring

28 November 2017. The Journal of Experimental Marine Biology and Ecology just published the latest study by our group looking at differences in the CO2 sensitivity of Atlantic silverside offspring stemming from different mothers. Congratulations to Jacob Snyder for his first peer-reviewed publication.

Among the highlights of the study:

  • Offspring produced by different females varied in their sensitivity to high CO2 conditions.
  • Specific fatty acids in eggs were correlated to the log-transformed CO2 response ratio of embryo survival and hatch length.
  • Maternal provisioning might be an additional determinant of CO2 sensitivity in fish early life stages.


Snyder, J.T.*, Murray, C.S.*, and Baumann, H. (2018)
Potential for maternal effects on offspring CO2 sensitivities in the Atlantic silverside (Menidia menidia).
Journal of Experimental Marine Biology and Ecology 499:1-8

Fig2 - dancing men
M. menidia. Responses to high CO2 conditions among replicates within and among females: (A) embryo and larval survival; (B) overall survival; (C) SL at hatch; and (D) final SL (16 dph). Patterns of larval growth were nearly identical to panel D and are therefore omitted. Ambient and high CO2 treatments are denoted by red and blue colors, respectively. Small symbols depict replicate survival (A,B) or replicate average size (C,D), while large symbols depict CO2 treatment averages for each female. Black lines connect average response for each female. Asterisks represent significant differences (P < 0.05) between CO2 levels within offspring of each female (Bonferroni adjusted t-test). Letters denote to females A to E.

[Lab news] Measuring juvenile silversides. Live.

10 October 2017. Today, Chris, Emma, and Julie measured over 400 juvenile Atlantic silversides for their length and weight. This time, however, we did not euthanize the fish before, but successfully measured them while still alive, only a little drowsy from the mild anesthetic we administered before.

Click on the video below to have a look for yourself.
Congratulations all, for a job well done!