Publications & Presentations

[e-lecture] Limnology & Oceanography publishes e-lecture on multistressors!

electure cover

A suite of parallel anthropogenic changes affects contemporary marine ecosystems. Excessive carbon dioxide (CO2) pollution results in warmer, more acidic oceans with lower dissolved oxygen (DO) levels, meanwhile the emission of reactive nitrogen/phosphorus results in eutrophication, excessive microbial degradation and thus metabolic hypoxia and acidification. Despite decades of empirical research how each individual stressor of the ‘climate-change syndrome’ (i.e., temperature, CO2, DO) affects the fitness of marine organisms, we still know little about the combined effects of these stressors. This lecture gives an overview over the nascent field of multi-stressor approaches evaluating the climate sensitivity of marine organisms across taxa. In most studied cases, combined effects of these stressors exceeded those observed individually. Effects of combined warming, acidification, and deoxygenation have mostly been additive (no stressor interaction) or synergistically negative (stressor interaction). The occurrence and strength of synergistic stressor interactions in some species, life history stages, and traits comprises a vexing challenge but hints at potentially greater sensitivities of organisms to marine climate change than previously recognized. This lecture is intended for post-secondary students, providing them with illustrated examples from the most resent literature, while aiding in communicating the urgent need for empirical data from multi-stressor approaches.

Baumann, H. (2016)
Combined effects of ocean acidification, warming, and hypoxia on marine organisms.
Limnology and Oceanography e-Lectures 6:1-43

[Talk] Future Ocean symposium (NYC) and the graphical recording of a presentation

Sustainable Ocean Development Symposium: A Perspective from Former, Current and Future Kiel Marine Scientists | September 28-30, 2015, New York City

H. Baumann gives invited lecture “Combined effects of ocean acidification and its co- stressors on marine organisms” at Columbia University

“I had no idea that ‘Graphical recording’ was a thing.

But Tracey Berglund, an artist currently living in NYC achieved with a whiteboard an a bunch of colored markers, what I wouldn’t have thought possible: a visually entertaining and remarkably accurate depiction of the main points of my talk, which highlighted the multistressor reality of climate change and the need for according experimental approaches.”

Head bowed, Tracey.”

See for yourself.

Graphical recording of H. Baumann's keynote lecture
Graphical recording of H. Baumann’s keynote lecture “Combined effects of ocean acidification and its co- stressors on marine organisms” (Artist: Tracey Berglund,
Baumann - Future Ocean Conference
Hannes Baumann delivers remarks about effects of ocean acidification and it’s co-stressors on marine organisms
Future Oceans Symposium at the Theological Seminary of Columbia University, NYC

[Presentation] H. Baumann talks at the 3rd Ocean Acidification PI Meeting in Woods Hole, MA

“Plastic and evolutionary responses to ocean acidification: navigating the difficult terrain between unfounded pessimism, optimism, and impossible tasks”

Woods Hole Oceanographic Institution, 11 June 2015

Experiments on contemporary marine organisms have demonstrated many negative responses to elevated CO2 levels, i.e., conditions that could occur in the average open ocean within the next 300 years. This has led to the recognition of ocean acidification (OA) as a key anthropogenic stressor and to concerns about detrimental changes to marine ecosystems on which humans depend. While assessing species sensitivities to OA has been the necessary first step, the gradual nature of these shifts further demands that we assess how transgenerational plasticity and evolutionary adaptation to OA will likely affect the overall vulnerability of species and ecosystems. Our predictive ability of these adaptive processes is still in its infancy.
Plastic & evolutionary responses to ocean acidification
The overview talk first looked at currently employed approaches to study adaptation, from relatively well-documented in vitro evolution to OA in single cell organisms to necessarily more inferential techniques (e.g., evolutionary potential, standing genetic variation, molecular techniques) in longer-lived metazoans where multi-generational experiments are largely unfeasible. Secondly, the talk touched on the likely role of transgenerational plasticity in mitigating adverse OA effects over shorter time-scales in some species and whether this could perhaps compromise their ability to genetically adapt. The final objective was to pose a number of largely unresolved questions (e.g., selection differentials? Evolutionary trade-offs?) and highlight a few, perhaps underutilized approaches (e.g., studying spatial gradients as analogies to temporal change) that might improve understanding of evolution and plasticity to OA.

The talk is publicly accessible on Prezi

[New Publication] Combining otolith microstructure and trace element analyses in Pacific bluefin tuna

A new study published in the ICES Journal of Marine Science suggests that analyzing the trace elements incorporated into the otoliths of bluefin tuna may allow inferring the arrival of juvenile fish in the California Current Ecosystem

Juvenile Pacific bluefin tuna (PBT, Thunnus orientalis) are known to migrate from western Pacific spawning grounds to their eastern Pacific nursery grounds in the California Current Large Marine Ecosystem, but the timing, durations, and fraction of the population that makes these migrations need to be better understood for improved management. This new study published in the ICES Journal of Marine Science suggests that analyzing the trace elemental composition of bluefin tuna otoliths may divulge the time of arrival of the juvenile fish on the Californian Shelf. Scientists from the University of Connecticut, Stony Brook University, Texas A&M, as well as from NOAA collaborated in this effort, hoping to further develop this method to better inform managers in the future.

Baumann, H., Wells, R.J.D., Rooker, J.R., Baumann, Z.A., Madigan, D.J., Dewar, H., Snodgrass, O.E., and Fisher, N.S. (2015) Combining otolith microstructure and trace elemental analyses to infer the arrival of Pacific bluefin tuna juveniles in the California Current Ecosystem. ICES Journal of Marine Science 72:2128-2138.
Free PDF and HTML access

[Campus Talk] H. Baumann talks at Avery Point Global Cafe

“Nets versus Nature: Have we indadvertedly made our fish smaller?”

Avery Point Global Cafe

April 9th 2015. H. Baumann contributed to Avery Point’s Global Cafe Series “The Omnivore at Sea” by talking about the topic of fisheries-induced evolution.
When hearing and talking about sustainable seafood, issues such as overfishing, fishing-related habitat destruction (e.g., trawls tearing through bottom habitat, dynamite fishing) or changes to the architecture of marine ecosystems (‘fishing down the foodweb’) often come to mind. Baumann talked about another potential effect of heavy decade-long commercial fishing, which is less clear but perhaps even more insidious. Nature’s age-old rule of survival in the ocean, i.e., that faster growing fish have better chances of survival, is suddenly reversed when size-selective fishing becomes the dominant agent of mortality. Because in fishing, a faster growing fish will just be susceptible sooner to get caught by the meshes of a fishing trawl. We instinctively know that life on earth has adjusted before to changing selection pressures, and there’s little reason to suspect that this case might be different. Commercial fishing may trigger fisheries-induced evolution, and this may mean smaller, earlier maturing fish and less total biomass for centuries to come. The brief talk will summarize the problem as we know it, explore alternative explanations and look at examples, which show that the issue is also inextricably linked to all the other natural and man-made changes (warming, food web) that affect fish stocks. A cautionary approach that considers evolutionary processes within the framework of sustainable fisheries is surely warranted.

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

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).


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