Impact of preservation techniques on pteropod shell condition
Pteropods have been a key focus of ocean acidification studies during the last decade due to their fragile aragonite shells and key role they play in polar ecosystems. Pteropods collected at sea are typically preserved before analysis at onshore laboratories. Despite the importance placed on pteropods as a sentinel for the impact of ocean acidification on marine calcifiers, there has never been a systematic study assessing how different preservation techniques affect the condition of pteropod shells. In this study we perform an experiment to assess the impact of six preservation techniques on the shell condition of Limacina retroversa pteropods. Using five shell condition-assessment methods, we find shells that were air dried were the least altered relative to the time of collection. Of the solution-based preservation techniques, shells were least altered when preserved in 70% buffered ethanol and most altered in a solution of sodium chloride buffered formalin. Our results have implications for the interpretation of pteropod shell condition in samples which have been stored in solution, and provide guidelines for the preservation of future pteropod collections.
KeywordsPteropod Preservation Dissolution Shell condition Sediment trap Museum collections
The authors would like to thank G. Stowasser, and the crew and scientists of JR15002 for help in collecting the samples. The authors offer their thanks to J. Gardner for her assistance in pteropod picking and for discussions on the cruise. The authors thank P. Wilf for allowing use of the microscope in the Paleobotany Laboratory; and J. Anderson and W. Auker at the Material Characterization Laboratory for their help with the SEM. The authors are extremely grateful to K. Jones-Williams for ranking the shells, and to the three anonymous reviewers whose comments greatly improved this manuscript. RLO received funding from the Hiroshi and Koya Ohmoto Graduate Student Fellowship. RLO and TJB received funding from the Deike Research Grant.
Compliance with ethical standards
Conflict of interest
This is an original submission. There are no conflicts of interest for any of the authors.
All applicable national and international guidelines for the care and use of animals were followed. Research was conducted in line with the Research Ethics Policy of the Pennsylvania State University.
- Howes EL, Eagle RA, Gattuso J, Bijma J (2017) Comparison of mediterranean pteropod shell biometrics and ultrastructure from historical (1910 and 1921) and present day (2012) samples provides baseline for monitoring effects of global change. PLoS ONE 1:1–23. https://doi.org/10.1594/PANGAEA.869200 Google Scholar
- Just J, Kristensen RM, Olesen J (2014) Dendrogramma, new genus, with two new non-bilaterian species from the marine bathyal of Southeastern Australia (animalia, metazoa incertae sedis)—with similarities to some medusoids from the Precambrian Ediacara. PLoS ONE 9:1–11. https://doi.org/10.1371/journal.pone.0102976 Google Scholar
- Lischka S, Büdenbender J, Boxhammer T, Riebesell U (2011) Impact of ocean acidification and elevated temperatures on early juveniles of the polar shelled pteropod Limacina helicina: mortality, shell degradation, and shell growth. Biogeosciences 8:919–932. https://doi.org/10.5194/bg-8-919-2011 CrossRefGoogle Scholar