Author: Hannes Baumann

[Publication] The combined effects of low pH and low oxygen on early life stages of three forage fish

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New experiments suggest both additive and synergistic negative effects of combined low pH and low oxygen on the early life stages of three common forage fish
New experiments suggest both additive and synergistic negative effects of combined low pH and low oxygen on the early life stages of three common forage fish

Coastal habitats often experience large diel to seasonal fluctuations in both pH and dissolved oxygen (DO), because ecosystem metabolism consumes oxygen while producing CO2. Hence, the two factors really represent two sides of the same coin. Decades of research have focused on hypoxia or acidification; therefore, the combined effects of these two stressors is still poorly understood. Master student Elizabeth Depasquale and co-authors tested the sensitivity to low pH and low DO in offspring of three forage fish species that are common in nearshore New England habitats: Inland silverside (Menidia beryllina), Atlantic silverside (M. menidia), and sheepshead minnow (Cyprinodon variegatus). The results show that pH and oxygen mostly have additive negative effects, but in a few cases also synergistically negative effects (Fig.1). The latter shows that multistressor experiments are important tools in assessing the impacts of multiple changes on coastal organisms.

Depasquale, E.*, Baumann, H., and Gobler, C.J. (2015) Variation in early life stage vulnerability among Northwest Atlantic estuarine forage fish to ocean acidification and low oxygen. Marine Ecology Progress Series 523: 145–156 http://dx.doi.org/10.3354/meps11142
Schematic response shapes illustrating the expected form of effect interaction between pH and oxygen on different early life history (ELH) traits
Schematic response shapes illustrating the expected form of effect interaction between pH and oxygen on different early life history (ELH) traits

[Press release] Evolving to cope with Climate Change

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Publication of Malvezzi et al. Evolutionary Applications (2015) “A quantitative genetic approach to assess the evolutionary potential of a coastal marine fish to ocean acidification”

Atlantic silversides Menidia menidia

Originally posted on UConn Today, by Tim Miller

Over the next two centuries, climate change is likely to impact everything from industrial agriculture to the shape of our coastlines. The changing climate will certainly cause huge changes around the world, and the challenge is to predict exactly what impact those changes will have.

In the world of marine science, this means grappling with a process called ocean acidification. As human activity pumps carbon dioxide into the atmosphere, some of the carbon dioxide gets absorbed into the sea, which raises its acidity.

Scientists have been concerned about this for more than a decade, says Hannes Baumann, an assistant professor of marine sciences who studies the phenomenon in his lab at UConn’s Avery Point campus. “The fundamental question,” he says, “is whether or not organisms can adapt to this threat.”

That question is important, because although ocean acidification is happening, it is a slow process. Levels of carbon dioxide in the atmosphere have increased more than 50 percent since the beginning of the Industrial Revolution. They are expected to undergo another four-fold increase, but over the course of the next 300 years.

“Three hundred years is only five or six generations for whales or long-lived sharks,” says Baumann, “or 300,000 generations of single-celled organisms.”

Recent work has thus focused on whether or not species can evolve along with the ocean, adapting over time to the increasing acidity.

Measuring evolutionary potential

In order to answer that question, Baumann and his colleagues turned to a small but important fish, the Atlantic silverside, Menidia menidia. Common across the shallow waters of eastern North America, the silverside is an important food source for aquatic birds like egret and cormorant, as well as commercially important fish species like bluefish and striped bass.

The researchers’ goal was to measure the so-called “evolutionary potential” of this species. It was already known that high levels of carbon dioxide would kill many, but not all, Atlantic silverside larvae. The researchers wanted to know whether the likelihood of surviving had a genetic component: if fish that were related to one another were more or less likely to survive in the new environment.

“We were basically trying to answer the question: Can they evolve?” Baumann says.

His team approached the problem by capturing wild silverside from a beach in Long Island Sound, and raising several groups of their offspring in the lab, some under normal ocean conditions, and some in a more acidic environment.

They then tracked how long each of the fish lived, and analyzed their DNA, looking for what are called “microsatellites” – the same repetitive strands of DNA that are used in human paternity tests. The analysis revealed which fish were related to one another.

The team found that related fish had similar lifespans, suggesting that there is indeed a significant genetic component to survival in an acidic ocean. This means that the fish does have the potential to evolve, a finding which may have important ramifications for predictions about how the ocean environment will change with the changing climate.

Baumann, who recently joined the faculty at UConn after an appointment at Stony Brook University, was enthusiastic about the result, primarily because it demonstrates a method by which the evolutionary potential of other species can be measured.

“This is an experiment that can be performed in one generation,” he says. He is hopeful that the results will prove useful in predicting how oysters, sea urchins, and a host of other marine organisms will be able to cope with the changing ocean environment.

The research was first published Feb. 14 online, and will appear in the March issue of the journal Evolutionary Applications.

This work was made possible by grants from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA).

 

Web coverage: UConn Today | NSF | OceanBites | ScienceDaily | AAAS EurekAlert | EnvResearchWeb | Phys.org | ScienceWR

[Lab News] Exploratory trip to Stellwagen Bank

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Sand lance caught on Stellwagen Bank in November 2014
Sand lance caught on Stellwagen Bank in November 2014

On November 10th Chris traveled to Stellwagen Bank Marine Sanctuary to test sample sand lance Ammodytes dubius, arguably the sanctuary’s most important resource. He joined a collaboration of researchers from the USGS and SBNMS to assist in their efforts to better understand sand lance distributions within the sanctuary. Given the vital importance of sand lance in many coastal systems, our lab is interested in evaluating how anthropogenic stressors, i.e. ocean acidification and hypoxia, may impact early life stages. The trip was an opportunity for Chris to observe field-sampling techniques aboard the R/V Auk, which confirmed the feasibility of sampling healthy, fertile adults. A special thanks to Ben Haskell, Dave Slocum, Brad Cabe, Michael Thompson from SBNMS; Page Valentine and Dann Blackmore from the USGS; and the crew of the R/V Auk for a great trip.

[Talk] 5th International Otolith Symposium

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Combining otolith microstructure + microchemistry: What can we learn about juvenile Pacific Bluefin Tuna migration?

Baumann et al. Otolith Symposium
H.Baumann presented findings about juvenile tuna otolith microstructure & -chemistry
From 19 – 24 October 2014, H. Baumann participated in the 5th International Otolith Symposium (Mallorca, Spain), a focused gathering of researchers worldwide analyzing calcified structures of fishes (otoliths = ear bones, scales, spines fin rays), mollusks and corals to infer age in days or years, isotopic or trace elemental composition, or to review the quality control measures in place in various production aging labs.
Dr. Baumann presented a study that combined daily ring analyses (=microstructure) in juvenile tuna otoliths with trace elemental analysis, showing that the otoliths likely record the entry of these fish into the California Current Ecosystem after their transpacific migration as juveniles.

[Talk] “Restore America’s Estuaries” Conference

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“Combined effects of low pH and low O2 on coastal organisms”

Baumann et al. talked about combined effects of acidification and hypoxia on coastal marine organisms
Baumann et al. talked about combined effects of acidification and hypoxia on coastal marine organisms
H.Baumann was invited to be one of four panel speakers during a session called “Acidifying our Estuaries – Global Problems, local effects” chaired by Dr. Denise Breitburg (SERC) during the “7th National Summit on Coastal and Estuarine Restoration” in Washington D.C. (1-5 November 2014, Gaylord Hotel & Convention Center). The talk covered recent results from work on early larval silversides and bivalves, showing that the combined negative effects of acidification and hypoxia need to be better understood and can at times be greater than additive (i.e., synergistic).In biology, sometimes 1 + 1 is greater than 2.

[Publication] “Detecting the unexpected: A research framework for ocean acidification”

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Pfister et al. Detecting the Unexpected ES & T
During a meeting of Principal Investigators of Ocean Acidification Research projects – a number of diverse minds came together and discussed for 3 days the state of the art and the future of Ocean Acidification Research. The result is a principled framework of directions based on three key observations and lessons learned from previous similar research challenges. (1) the response of individuals does not necessarily predict the response of ecosystems, (2) the structure and function of ecosystems may respond differently to OA, and (3) much of our current research thrust is still going towards understanding individual species responses to the predicted changes in ocean carbon chemistry, whereas much needed attention to interactions between organism and ecosystems and ecosystem and ocean chemistry is still wanting.
Pfister, C., Esbaugh, A., Frieder, C., Baumann, H., Bockmon, E., White, M., Carter, B., Benway, H., Blanchette, C. Carrington, E., McClintock, J., McCorkle, D., McGillis, W., Mooney, T., Zivieri, P. (2014). Detecting the unexpected: A research framework for ocean acidification. Environmental Science & Technology 48: 9982-9994

[Publication] “Offspring sensitivity to ocean acidification changes seasonally in a coastal marine fish”

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MEPS Feature Cover
Novel experiments on wild Atlantic silversides Menidia menidia suggest that parents are capable of pre-conditioning their offspring to the naturally occurring, seasonal acidification in their spawning habitat (shape depicts the annual pattern of pH mean, minimum and maximum.)
How vulnerable are marine organisms to unfolding ocean acidification? Apart from being species- and habitat-specific, the answer may even differ between times of the year. Other than open ocean species, most coastal organisms naturally experience large seasonal pH fluctuations, to which they have adapted. Murray and co-workers monitored pH conditions in the spawning habitat of a common coastal marine fish, while sampling wild spawning adults repeatedly over the season and conducting standardized CO2 exposure experiments on their offspring. This demonstrated that offspring CO2 sensitivity is not constant, but decreases seasonally with the increasing acidification in their habitat. These findings imply that realistic assessments of species CO2 sensitivities should account for the pH/CO2 variability in the parental environment.
Murray, C.M., Malvezzi, A., Gobler, C.J., and Baumann, H.(2014) Offspring sensitivity to ocean acidification changes seasonally in a coastal marine fish. Marine Ecology Progress Series 504: 1-11 (Open Access)