October 10th 2016 was a special day for our still young lab here at the University of Connecticut, Today, the ICES Journal of Marine Science published the paper of Chris Murray et al., which is the first of hopefully many publications of our experimental findings originating out of our new laboratory facility here at UConn Avery Point.
Chris and his co-authors report on a large-scale, quantitative rearing experiment on Atlantic silversides eggs, larvae and juveniles under contrasting CO2 conditions that took place between May – September 2015. This novel experiment was designed to address three critical issues lacking in previous ocean acidification research on fish. First, the study spanned several ontogenetic stages. Second, it used very large numbers of individuals to robustly characterize not just potential shifts in mean responses, but also changes in the distribution of length, weight, and condition factor. Third, it provided food at standardized, non-excess levels to prevent that potential metabolic costs of high CO2 exposure could be compensated by survivors simply by eating more food.
Overall the study demonstrated seemingly small but significant growth reductions due to high CO2 and identified a small number of fatty acids that were of significantly different concentrations in high vs. control juveniles.
This small conference brought together approximately 150 international scientists to talk about larval fish growth, survival, maternal effects, dispersal, systematics to name just a few. It was held in special honor of Edward Houde, who over his long career has inspired generations of marine scientists.
While Chris was presenting last years data about growth consequences of high CO2 exposure across life stages in our model species, the Atlantic Silverside, Hannes participated in the Early Career workshop and gave a talk about how to approach the writing of a scientific manuscript (PDF).
On 12 May 2016, the Department of Marine Science hosted it’s 11th Biennial Feng Graduate Research Colloquium, during which graduate students of the department traditionally present findings of their thesis research and/or give a preview of their future plans.
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.
Examples for synergistic negative effects of low DO and low pH (high CO2) on different traits and marine taxa. (a) Synergistic decrease in respiration rate in small and big sea urchins ; (b) growth rate of juvenile quahog was unaffected by low DO or low pH individually, but decreased under combined stressor conditions ; (c) survival of Atlantic silverside larvae to 10 dph. Survival was robust against low pH and sensitive to low DO, but decreased synergistically under combined stressors (green arrow, ); (d) representation of Po ̈rtners  ‘Oxygen- and capacity-limited thermal tolerance’ framework, adapted to the multiple stressor scenario of acidification and hypoxia.
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.
On 13 April, Hannes was invited to the board meeting of the Mumford Cove Association to present a brief update about our groups research activities in and around the cove. It is part of our commitment to public education and outreach to keep property owners informed and maintain good relationships with all parties involved.
The information material below contains graphical summaries of our activities, i.e., measuring water quality parameters continuously with a logging probe and conducting biweekly beach seine surveys for silversides.
On 15 March, Hannes gave a lecture at Mitchell College in New London, talking about the combined effects of ocean warming, acidification, and hypoxia on marine organisms. The entire lecture is publicly available at Limnology & Oceanography e-lectures.
“It was such a pleasure to have you present to the class today; your lecture was excellent – engaging with just the right amount and level of information. I’m glad that you intend to continue to provide outreach/education to the community on this topic.”
On 26 February 2016, H. Baumann was invited to give a seminar at the Biological & Environmental Sciences Colloquium Series at the University of Rhode Island, featuring the recently published e-lecture on “Combined effects of ocean acidification, warming, and deoxygenation on marine organisms”
His host, David Bengston has been a renowned fisheries and aquaculture biologist for the past 40 years.
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.
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.”