This year, Chris presented the results of last years study on long-term changes in growth distributions in Atlantic silversides exposed to high CO2 conditions, whereas Jake presented a poster outlining his thesis research on long-term environmental and biological data collected by Project Oceanology.
Gobler & Baumann’s review provides a good overview over the nascent field of multi-stressor acidification and hypoxia work. A first part firmly establishes that virtually all hypoxic zones in the ocean are also acidified, given that metabolic processes (i.e., respiration) consume oxygen and release CO2 into the environment. In a second part, the sparse emerging evidence for multistressor effects of low pH (high CO2) and low oxygen are reviewed, showing that while the majority of effects are additively negative, every study so far has also found synergistically negative effects of combined stressors in at least one trait.
This invited review was published Open Access.
Gobler, C.J. and Baumann, H. (2016)
Hypoxia and acidification in ocean ecosystems: Coupled dynamics and effects on marine life.
Biology Letters 12:20150976
There is increasing recognition that low dissolved oxygen (DO) and low pH conditions co-occur in many coastal and open ocean environments. Within temperate ecosystems, these conditions not only develop seasonally as temperatures rise and metabolic rates accelerate, but can also display strong diurnal variability, especially in shallow systems where photosynthetic rates ameliorate hypoxia and acidification by day. Despite the widespread, global co-occurrence of low pH and low DO and the likelihood that these conditions may negatively impact marine life, very few studies have actually assessed the extent to which the combination of both stressors elicits additive, synergistic or antagonistic effects in marine organisms. We review the evidence from published factorial experiments that used static and/or fluctuating pH and DO levels to examine different traits (e.g. survival, growth, metabolism), life stages and species across a broad taxonomic spectrum. Additive negative effects of combined low pH and low DO appear to be most common; however, synergistic negative effects have also been observed. Neither the occurrence nor the strength of these synergistic impacts is currently predictable, and there- fore, the true threat of concurrent acidification and hypoxia to marine food webs and fisheries is still not fully understood. Addressing this knowledge gap will require an expansion of multi-stressor approaches in experimental and field studies, and the development of a predictive framework. In consider- ation of marine policy, we note that DO criteria in coastal waters have been developed without consideration of concurrent pH levels. Given the per- sistence of concurrent low pH–low DO conditions in estuaries and the increased mortality experienced by fish and bivalves under concurrent acidifi- cation and hypoxia compared with hypoxia alone, we conclude that such DO criteria may leave coastal fisheries more vulnerable to population reductions than previously anticipated.
We are happy to announce the continued support of the National Science Foundation, Division of Biological Oceanography, which just started to fund our project about multi-stressor effects on the early life stages of fish. This is collaborative work with Prof. Janet Nye’s lab at Stony Brook University, NY, which will strengthen ties between UConn and Stony Brook Marine Sciences. The work has already started and we’re looking forward to new discoveries!
Baumann, H. and Nye, J. 2015. Collaborative research: Understanding the effects of acidification and hypoxia within and across generations in a coastal marine fish. NSF Project# 1536336 (3 years)
Learn more by accessing the NSF-OCE non-technical proposal abstract
Thumbs up, and fingers crossed for the next steps!
By Jacob Snyder:
Chris and I meet up, grab the supplies we need (buckets, bags, coolers, aerators, etcetera), and start making our way to Scituate, Mass. Today we are going out on the NOAA vessel “Auk,” with a few members from NOAA and the USGS. Our goal? To collect approx. 200 Northern Sand Lance, Ammodytes dubius.
We boarded the ship …
Read the whole post and see all the pictures on Jake’s blog @ Red Skies Photography
Check out the footage from the day, thanks to Jake and his GoPro. Check-out the video from the second sampling trip about one month later, too!
Yencho, M.A, Jordaan, A., Cerrato, R.M., Baumann, H., and Frisk, M.G. (2015) Growth and mortality in coastal populations of Winter Flounder: implications for recovery of a depleted population.
Marine and Coastal Fisheries 7: 246-259.
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.
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.
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”
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).