Month: June 2015

[Publication] Comparing different growth proxies in young juvenile sprat

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Reliable estimates of short- and longer-term in situ growth and condition of organisms are critical if one hopes to understand how the environment regulates survival. This laboratory study reports the first comparison of somatic- (K), biochemical- (RNA–DNA ratio, RD) and otolith- (increment widths, OIW) based indices of condition of a young juvenile fish. It found that RNA:DNA ratios react 2x faster to growth changes due to changes in feeding level than otolith increment widths, while condition factor was the most variable proxy.
Peck et al study

Peck, M. A., H. Baumann, C. Clemmesen, J. P. Herrmann, M. Moyano, and A. Temming 2015. Calibrating and comparing somatic-, nucleic acid-, and otolith-based indicators of growth and condition in young juvenile European sprat (Sprattus sprattus). Journal of Experimental Marine Biology and Ecology 471:217-228.

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

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“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

[Lab News] Seining in Mumford Cove

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Here are some pictures from one of our first beach seining trips to Mumford Cove, CT (16 May 2015)

Seining and water sampling in Mumford Cove, CT
Seining and water sampling in Mumford Cove, CT
Hannes and Chris in Mumford Cove, discussing how to sort the catch of silversides collected by beach seine
Hannes and Chris in Mumford Cove, discussing how to sort the catch of silversides collected by beach seine
Male and female silverside are separated and transported to our laboratory facility (Rankin Lab, UConn)
Male and female silverside are separated and transported to our laboratory facility (Rankin Lab, UConn)
Sorting the catch of the beach seine, Mumford Cove 16 May 2015
Sorting the catch of the beach seine, Mumford Cove 16 May 2015
Seining in Mumford Cove, CT
Seining in Mumford Cove, CT

[Lab News] Our new rearing system is operational!

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– The maiden voyage –
Although it still lacks a proper name, our experimental system to rear larval fish under different temperature, CO2, and oxygen conditions has finally started it’s first real trial with newly fertilized silverside embryos. The system consists of 9 independent units to allow any factorial 3 x 3 combination of rearing conditions. Each unit has a sealed main tank (400L) in which up to six individual rearing containers (20L) can be placed. Water samples from each unit are sequentially pumped past two wall-mounted oxygen and pH sensors, which feed their data into a computer program called LabView (NI), which in turn triggers solenoid valves to add CO2, nitrogen, or air to each system. Although straightforward in principle, the practice of putting all of this together is definitely more complicated and the devil in the detail. All told, the construction took us ~ 8 months, but we hope to be using this system for years from now.

Thumbs up to the many, many persons that were instrumental to the success of this; Paul Grecay and Timothy Targett (University of Delaware) for giving us the crucial inspiration about the general design of a system like that. Gary Grenier and Bob Dziomba from the machine shop for building the big pieces and thinking ahead of details that we certainly would have missed. Charlie Woods for his excellent help and assistance in the Rankin Lab, from plumbing to electrical to simply cheering us up. Dennis Arbige for taking on the tedious wiring of the solenoids without blinking an eye. Finally, many thanks to John Hamilton who’s excellent knowledge of LabView and great teaching skills helped Chris to become a LabView wiz in a matter of weeks!

Ready. Set. Go!