Guest Essay by Kip Hansen
When I wrote “Ocean Acidification: Trying to Get the Science Right” , I sent Dr. Christopher Cornwall, lead author of Cornwall & Hurd 2015, a courtesy advanced copy of the essay, inviting him to comment. Dr. Cornwall was away doing field work at the time, but on his return has supplied the following: (his words in italics)
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…. I am not trying to defend the inappropriately designed or analysed papers, but feel that these points could be useful to your readers,
“The field of ocean acidification has a few logistical constraints (mentioned in the paper) that make it more challenging than many other fields of research. Other than appropriate replication and randomisation, there are many other components that make up the methodological merits of paper. For example, correctly measuring and manipulating carbonate chemistry, the ecological/environmental realism of the experimental conditions, and the utility of the prescribed treatments in testing the hypotheses posed. Therefore, while the majority of ocean acidification studies may be carefully designed in many of the aspects mentioned above, it is clear that not all studies are perfect in every facet. If any given field of research was examined in a similar way I would be surprised if the number of perfectly designed studies was high.
Many “classic” papers in the infancy of ecology were conducted using limited replication; future research then built on their findings to improve our knowledge. The same phenomenon is occurring here in ocean acidification research – and the same process of refinement will likely occur in other fields of research in the future if it has not already. The money spent by governments on ocean acidification was, in most cases, spent wisely. The same findings that appear in many of the first classic papers have been repeated using appropriate experimental methods. As well as in the laboratory studies we examined, these findings have also been represented in field experiments. It is now clear that ocean acidification will negatively impact marine ecosystems through alteration of the behaviour of many fish and invertebrate species, and through reductions in the calcification of many (but not all) calcifying species. The key now is for ocean acidification research to continue to improve and provide a benchmark for other fields of research.”
Subsequently, I wrote and asked Dr. Cornwall’s opinion on this question:
As widespread significantly lowered pH is expected only to take place gradually on a century scale, how predictive can we expect results to be from immediate-to-rapid (weeks or months) reduction of pH? What is the thinking on this issue in the OA field? What research procedures are planned or in use to find out now, without waiting the requisite 100 years?
“Yes, there has also been discussion in the OA community about whether experiments represent initial shock responses or realistic responses. There are a number of experiments that gradually ramp pH down to test the effects – the results so far are not clear cut, but this is definitely another aspect to be considered in future research. Some of the short-duration research in my sub-field (macroalgae) usually show less dramatic effects than longer experiments, which indicates to me that responses generally are not an initial shock responses – but more research is required on this topic, and I cannot say for certain that the responses of some studies are not “shock” responses.
Also, there has been a number of studies examining whether organisms could adapt to OA, or whether organisms from habitats with high variability in pH could already possess traits beneficial to them under OA. The results of these studies are also not clear cut as yet unfortunately – though this is an avenue of research that is expanding currently.
Attached is a paper** looking at dramatic versus gradual exposure to low pH seawater.”
And while I am sure that Chris is fully aware that I do not share his certainty about the future negative effects of ocean acidification, it is a pleasure to be able to interact with him in such a collegial and professional manner. If only it were so with so many others who should be our colleagues in the various fields related to climate science.
For the future of OA?
For the research field known as OA, I would call for a full Cochrane-style review * of the research to date, using only the very best studies, those properly designed, carried out with correct chemistry, analysed with appropriate statistical methods and taking into account the proper time frames in order to estimate our actual current state of knowledge on the subject. Chris Cornwall and Catriona Hurd are already well positioned to do such a work.
In light of the acknowledged white hat and confirmation bias that exists in the field, I support John Ioannidis who suggests the following for all scientific fields: “large studies with minimal bias should be performed on research findings that are considered relatively established, to see how often they are indeed confirmed. I suspect several established ‘classics’ will fail the test.” (my italics)
It is so very easy to fool ourselves about science – medical research has shown this over and over: reversals of “givens” both in medical theory, clinical practice and hopeful looking cures and treatments are almost the norm when gold standard RCT trials are performed on treatments which are already widely practiced and/or popularly accepted. What “everybody knows” has seldom been sufficiently verified and is often found incorrect.
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* — “Cochrane Reviews are systematic reviews of primary research in human health care and health policy, and are internationally recognised as the highest standard in evidence-based health care. “
** — “Coralline algal structure is more sensitive to rate, rather than the magnitude, of ocean acidification” KAMENOS et al 2013 — Global Change Biology (2013) 19, 3621–3628, doi: 10.1111/gcb.12351
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Author’s Comment Policy: This piece is mostly made up of Dr. Cornwall’s response to an earlier essay, his opinions and words. He has been notified of its posting and has received an advanced copy. He may choose to participate in comments.
I (Kip Hansen) will respond to comments directed specifically to me, such as : “Kip – Thanks for highlighting this work…can you tell us….?”. Of course, I cannot comment for Dr. Cornwall or answer questions about his opinions – he has stated them very clearly.
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