GD
Geodynamics
Grace Shephard / Tobias Meier

Guest

Find out more about the blog team here.

The past is the key

The past is the key

Lorenzo Colli

“The present is the key to the past” is a oft-used phrase in the context of understanding our planet’s complex evolution. But this perspective can also be flipped, reflected, and reframed. In this Geodynamics 101 post, Lorenzo Colli, Research Assistant Professor at the University of Houston, USA, showcases some of the recent advances in modelling mantle convection.  

 

Mantle convection is the fundamental process that drives a large part of the geologic activity at the Earth’s surface. Indeed, mantle convection can be framed as a dynamical theory that complements and expands the kinematic theory of plate tectonics: on the one hand it aims to describe and quantify the forces that cause tectonic processes; on the other, it provides an explanation for features – such as hotspot volcanism, chains of seamounts, large igneous provinces and anomalous non-isostatic topography – that aren’t accounted for by plate tectonics.

Mantle convection is both very simple and very complicated. In its essence, it is simply thermal convection: hot (and lighter) material goes up, cold (and denser) material goes down. We can describe thermal convection using classical equations of fluid dynamics, which are based on well-founded physical principles: the continuity equation enforces conservation of mass; the Navier-Stokes equation deals with conservation of momentum; and the heat equation embodies conservation of energy. Moreover, given the extremely large viscosity of the Earth’s mantle and the low rates of deformation, inertia and turbulence are utterly negligible and the Navier-Stokes equation can be simplified accordingly. One incredible consequence is that the flow field only depends on an instantaneous force balance, not on its past states, and it is thus time reversible. And when I say incredible, I really mean it: it looks like a magic trick. Check it out yourself.

With four parameters I can fit an elephant, and with five I can make him wiggle his trunk

This is as simple as it gets, in the sense that from here onward every additional aspect of mantle convection results in a more complex system: 3D variations in rheology and composition; phase transitions, melting and, more generally, the thermodynamics of mantle minerals; the feedbacks between deep Earth dynamics and surface processes. Each of these additional aspects results in a system that is harder and costlier to solve numerically, so much so that numerical models need to compromise, including some but excluding others, or giving up dimensionality, domain size or the ability to advance in time. More importantly, most of these aspects are so-called subgrid-scale processes: they deal with the macroscopic effect of some microscopic process that cannot be modelled at the same scale as the macroscopic flow and is too costly to model at the appropriate scale. Consequently, it needs to be parametrized. To make matters worse, some of these microscopic processes are not understood sufficiently well to begin with: the parametrizations are not formally derived from first-principle physics but are long-range extrapolations of semi-empirical laws. The end result is that it is possible to generate more complex – thus, in this regard, more Earth-like – models of mantle convection at the cost of an increase in tunable parameters. But what parameters give a truly better model? How can we test it?

Figure 1: The mantle convection model on the left runs in ten minutes on your laptop. It is not the Earth. The one on the right takes two days on a supercomputer. It is fancier, but it is still not the real Earth.

Meteorologists face similar issues with their models of atmospheric circulation. For example, processes related to turbulence, clouds and rainfall need to be parametrized. Early weather forecast models were… less than ideal. But meteorologists can compare every day their model predictions with what actually occurs, thus objectively and quantitatively assessing what works and what doesn’t. As a result, during the last 40 years weather predictions have improved steadily (Bauer et al., 2015). Current models are better at using available information (what is technically called data assimilation; more on this later) and have parametrizations that better represent the physics of the underlying processes.

If time travel is possible, where are the geophysicists from the future?

We could do the same, in theory. We can initialize a mantle convection model with some best estimate for the present-day state of the Earth’s mantle and let it run forward into the future, with the explicit aim of forecasting its future evolution. But mantle convection evolves over millions of years instead of days, thus making future predictions impractical. Another option would be to initialize a mantle convection model in the distant past and run it forward, thus making predictions-in-the-past. But in this case we really don’t know the state of the mantle in the past. And as mantle convection is a chaotic process, even a small error in the initial condition quickly grows into a completely different model trajectory (Bello et al., 2014). One can mitigate this chaotic divergence by using data assimilation and imposing surface velocities as reconstructed by a kinematic model of past plate motions (Bunge et al., 1998), which indeed tends to bring the modelled evolution closer to the true one (Colli et al., 2015). But it would take hundreds of millions of years of error-free plate motions to eliminate the influence of the unknown initial condition.

As I mentioned before, the flow field is time reversible, so one can try to start from the present-day state and integrate the governing equations backward in time. But while the flow field is time reversible, the temperature field is not. Heat diffusion is physically irreversible and mathematically unstable when solved back in time. Plainly said, the temperature field blows up. Heat diffusion needs to be turned off [1], thus keeping only heat advection. This approach, aptly called backward advection (Steinberger and O’Connell, 1997), is limited to only a few tens of millions of years in the past (Conrad and Gurnis, 2003; Moucha and Forte, 2011): the errors induced by neglecting heat diffusion add up and the recovered “initial condition”, when integrated forward in time (or should I say, back to the future), doesn’t land back at the desired present-day state, following instead a divergent trajectory.

Per aspera ad astra

As all the simple approaches turn out to be either unfeasible or unsatisfactory, we need to turn our attention to more sophisticated ones. One option is to be more clever about data assimilation, for example using a Kalman filter (Bocher et al., 2016; 2018). This methodology allow for the combining of the physics of the system, as embodied by the numerical model, with observational data, while at the same time taking into account their relative uncertainties. A different approach is given by posing a formal inverse problem aimed at finding the “optimal” initial condition that evolves into the known (best-estimate) present-day state of the mantle. This inverse problem can be solved using the adjoint method (Bunge et al., 2003; Liu and Gurnis, 2008), a rather elegant mathematical technique that exploits the physics of the system to compute the sensitivity of the final condition to variations in the initial condition. Both methodologies are computationally very expensive. Like, many millions of CPU-hours expensive. But they allow for explicit predictions of the past history of mantle flow (Spasojevic & Gurnis, 2012; Colli et al., 2018), which can then be compared with evidence of past flow states as preserved by the geologic record, for example in the form of regional- and continental-scale unconformities (Friedrich et al., 2018) and planation surfaces (Guillocheau et al., 2018). The past history of the Earth thus holds the key to significantly advance our understanding of mantle dynamics by allowing us to test and improve our models of mantle convection.

Figure 2: A schematic illustration of a reconstruction of past mantle flow obtained via the adjoint method. Symbols represent model states at discrete times. They are connected by lines representing model evolution over time. The procedure starts from a first guess of the state of the mantle in the distant past (orange circle). When evolved in time (red triangles) it will not reproduce the present-day state of the real Earth (purple cross). The adjoint method tells you in which direction the initial condition needs to be shifted in order to move the modeled present-day state closer to the real Earth. By iteratively correcting the first guess an optimized evolution (green stars) can be obtained, which matches the present-day state of the Earth.

1.Or even to be reversed in sign, to make the time-reversed heat equation unconditionally stable.

Geodynamics in Planetary Science

Geodynamics in Planetary Science

It is a question that humankind has been asking for thousands of years:

Are we alone in the Universe or are there other worlds like our own?

As of today, it is unknown whether or not inhabited planets exist outside of our own solar system. With the discovery of the extrasolar planet 51 Peg b in 1992, it was confirmed that our sun is not the only star that hosts planets and therefore the search for extraterrestrial life has expanded beyond our own solar system.
However, before we look for an inhabited exoplanet, we must understand what makes a planet habitable.
Of course, the best example of an inhabited (and hence habitable) planet is our Earth and therefore it is a reasonable approach to first look for Earth-like planets. So, the question we should ask is

What makes Earth habitable?

  • The planet should be in the so-called habitable zone: the zone where the planet contains liquid water on its surface. One usually calculates this zone assuming an Earth-like atmosphere.  [e.g. Lammer et al., 2009]
  • The planet also needs to have an atmosphere that protects it from radiation but also keeps the planet warm with greenhouse gases. [e.g. Seager, 2013]
  • The planet should be made of rock and should have a molten core. A convective outer core gives rise to a magnetic field that protects the planet from solar winds and cosmic rays. [e.g. Shahar et al., 2019]

Interestingly, we can couple all three points: greenhouse gases in the atmosphere can heat a planet that is too far away from its host star and therefore make it habitable. On the other hand, they can also heat a planet too much such that it becomes inhabitable.
The third point (a planet made of rock with a molten core) brings geodynamics into play: plate tectonics and volcanic outgassing contribute to burial and recycling of atmospheric gases [Seager, 2013].
In our solar system, Earth is the only inhabited planet, and it is also the only planet we know of that exhibits plate tectonics (including exoplanets).
For example, Venus, our neighbouring sister planet, is very similar to Earth in terms of size, mass and composition. Some studies even suggest that Venus might have been the first habitable planet of our solar system [Way et al., 2016].
But present-day Venus is an inhospitable planet with a very thick carbon dioxide atmosphere (90 times denser than that of Earth) and an extremely hot surface temperature (up to 750K) which is mainly because of runaway greenhouse gases. But why did Earth become habitable and Venus did not?
To explain their different evolutionary paths, plate tectonics might play a major role. Through plate tectonics, Earth can efficiently recycle carbon back into its surface (deep carbon cycle) and this may help to prevent a runaway Greenhouse effect.

The importance of plate tectonics on the habitability of a planet is still being studied, and it is not yet fully understood how efficient this recycling is.

Plate tectonics also influences the generation of a magnetic field. Plate tectonics efficiently cools the mantle by subducting cold slabs into the deep interior, which leads to high heat flow out of the core. Therefore, the style of mantle convection controls the convection in the outer core. This then generates the magnetic field of a planet. The magnetic field acts as a protective shield from the solar winds, which otherwise might erode the planet’s atmosphere. As discussed above, the atmosphere controls the climate mainly through greenhouse gases. The resulting climate influences the tectonic regime: cool climates are favourable for plate tectonics because they facilitate the formation of weak shear-zones in the lithosphere [Foley et al., 2016].
This coupling between the climate, mantle and the core is called the “whole planet coupling” [Foley et al., 2016] and as a whole, it might explain why Earth and Venus have evolved so differently.

Whole planet coupling“: The atmosphere controls the climate which influences the tectonic regime. Subducting slabs cool the mantle which leads to high heat flow out the core. Therefore, the mantle convection controls the type of convection in the outer core which can generate a magnetic field. The magnetic field protects the atmosphere from solar winds and cosmic rays.

To understand the habitability of exoplanets, we therefore need to investigate all the components of the whole planet coupling. Most interestingly for geodynamicists, it is the interior dynamics of a planet’s mantle that couples all these different components!

In the past years, astronomers have discovered many exoplanets, and we expect many more to join this list. For some of them, astronomers and astrophysicists can measure its size, mass, and sometimes even the atmospheric composition and/or surface temperature.
This is very different from studying the Earth, where we can gather a lot of information about the interior through, for example, seismology. Geophysicists, Astronomers, Astrophysicists and many other research disciplines have to collaborate such that they can understand an exoplanet’s whole planet coupling and potential habitability. For geodynamicists the challenge will be to infer the exoplanet’s interior dynamics from a limited amount of data only.

References:
Foley, B. J. and Driscoll, P. E.: Whole planet coupling between climate, mantle, and core: Implications for the evolution of rocky planets, Geochemistry, Geophysics, Geosystems, Vol. 17, 2016.
Lammer, H., et al.: What makes a planet habitable?, The Astronomy and Astrophysics Review, Vol. 17, 2009.
Seager, S.: Exoplanet Habitability. Science, Vol. 340, 2013.
Shahar, A., Driscoll, P., Weinberger, A. and Cody, G.: What makes a planet habitable?, Science, Vol. 364, 2019.
Way, M. J., et al.: Was Venus the first habitable world of our solar system?, Geophysical Research Letters, Vol. 43, 2016.

GD Guide to EGU19

GD Guide to EGU19

With this year’s EGU General Assembly (GA; #EGU19) looming in less than a week, it’s time for all attendees to finish (or start) their own scientific contributions, create their own personal programs as well as plan other activities during the conference. In this blog Nico Schliffke (GD ECS Rep) would like to share some useful advice how to successfully navigate through the conference and highlight relevant activities, both scientific and social, for Geodynamics Early Career Scientists (ECS).

The huge variety of scientific contributions (~18,000 at EGU18) might seem intimidating to begin with and makes it impossible for any individual to keep track of everything. To be well prepared for the conference, allow for a bit of time to create your own personal programme by logging in with your account details and search for relevant sessions, keywords, authors, friends or any other fields of interest. If you have found anything interesting, add it to your personal programme by ticking the ‘star’. After completing your personal programme you can print your own timetable or open it in the EGU 2019 app.

Besides all the (specific) scientific content of the GA, EGU19 offers a wide spread of exciting workshops and short courses to boost your personal and career skills, as well great debates, union wide events and division social events. Below you will find a list of highlight events, special ECS targeted events, social events and other things to keep in mind and to make the best of EGU19:

For first time attendees:

How to navigate the EGU: tips and tricks (Mon, 08:30 – 10:15, Room -2.16) – This workshop is led by several EGU ECS representatives and will give an overview of procedures during EGU as well as useful tips and tricks how to successfully navigate the GA.

GD workshops and short courses:

Geodynamics 101A: Numerical methods (Thur, 14:00-15:45, Room -2.62) Building on last year’s short course, we are happy to announce two short courses this year as a part of the ’Solid Earth 101’ series together with Seismology 101 and Geology 101. The first course deals with the basic concepts of numerical modelling, including discretisation of governing equations, building models, benchmarking (among others).

Geodynamics 101B: Large-scale dynamical processes (Fri, 14:00-15:45, Room -2.62)  The second short course will discuss the applications of geodynamical modelling. It will cover a state-of-art overview of main large-scale dynamics on Earth (mantle convection, continental breakup, subduction dynamics, crustal deformation..) but also discuss constraints coming from seismology (tomography) or the geological record.

Geology 101: The (hi)story of rocks (Tue, 14:00 – 15:45, Room -2.62)The complementary workshop in the 101 series: Find more about structural and petrological processes on Earth. It’s definitely worth knowing, otherwise why should we be doing many of these Geodynamical models?

Seismology 101 (Wed, 14:00 – 15:45, Room -2.62)The second complementary workshop in the 101 series. Many geodynamical models are based on observations using seismological methods. Find out more about earthquakes, beachballs and what semiologists are actually measuring – this is essential for any numerical or analogue geodynamical model!

GD related award ceremonies and lectures:

Arne Richter Award for Outstanding ECS Lecture by Mathew Domeier (Tue, 12:00-12:30 Room -2.21) – The Arne Richter award is an union-wide award for young scientists. We are happy to see that Mathew as a Geodynamicist has won the medal this year! Come along and listen to his current research.

Augustus Love Medal Lecture by Anne Davaille (Thur, 14:45-15:45, Room D1) – Listen to the exciting work of the first female winner of the Augustus Love Medal (the GD division award), Anne Davaille! She is specialised on experimental and analytical fluid dynamics which has given Geodynamics many new insights.

 Arthur Holmes Medal Lecture by Jean Braun  (Tue, 12:45-13:45, Room E1) – This one of the most prestigious EGU award for solid Earth geosciences. Jean is a geodynamicist from Potsdam and works on integrating surface and lithospheric dynamics into numerical models.

 

 

GD division social activities:

ECS GD informal lunch  (Mon, 12:30-14:00) – Come and meet the ECS team behind these GD activities! Meet in front of the conference center (look for “GD” stickers), to head to the food court in Kagran (2 subway stops away from the conference center, opposite direction to city centre).

ECS GD dinner (Wed, 19:30-22:00) – Join us for a friendly dinner at a traditional Viennese ‘Heurigen’ with fellow ECS Geodynamicists at Gigerl – Rauhensteingasse 3, Wien 1. Bezirk!  If you would like to attend the ECS GD dinner on Wednesday, please fill out this form to keep track on the number of people: https://docs.google.com/forms/d/e/1FAIpQLScpi8gvDDMOOOjLbtq4BrElsoBtTv86Mud7qNQ5yl7qWP5cUA/viewform  Remember to bring some cash to pay for your own food and drinks!

GD/TS/SM drinks (Wed, after ECS GD dinner) – Don’t worry if you cannot make for the ECS GD dinner! After dinner we’ll have a 5 min walk to Bermuda Bräu – Rabensteig 6, 1010 Wien for some drinks together with ECS from Seismology (SM) and Tectonics/Structural (TS), so you can meet us there too!  

GD Division meeting (Fri, 12:45-13:45 Room D2) – Elections and reports from the division president, ECS representative and other planning in GD related matters. Lunch provided!

Meet the division president of Geodynamics (Paul Tackley) and the ECS representative (Nico Schliffke) (Wed, 11:45-12:30, EGU Booth) – Come and discuss with the president and ECS rep about any GD related issues, suggestions or remarks.

Geodynamicists eating lunch at Kagran – it’s tradition by now.

EGU wide social activities:

Networking and ECS Zone (all week – red area)This area is dedicated to early career scientist all week and provides space to chillout, get your well deserved coffee or find out more about ECS related announcements.

Opening reception (Sun, 18:30 – 21:00, Foyer F) – Don’t miss out on many new faces and friends, as well as free food and drinks and the opening (ice-breaker) reception! There will also be a ECS corner to meet fellow young scientists, especially if it’s your first EGU.

EGU Award Ceremony (Wed, 17:30 – 20:00, Room E1) – All EGU medallists will receive their award at this ceremony.

ECS Forum (Wed, 12:45 – 13:45, Room L2)An open discussion on any ECS topic

ECS Networking and Careers Reception (by invitation only) (Tue, 19:00-20:30, Room F2)

Conveners’ reception (by invitation only) (Fri 19:30 – 0:00, Foyer F) 

Credit: Kai Boggild (distributed via imaggeo.egu.eu)

Great debates

Science in policymaking: Who is responsible?  (Mon, 10:45 – 12:30, Room E1) – Actively take part in one of the presently most important and hot topic!

How can Early Career Scientists prioritise their mental wellbeing? (Tue, 19:00 – 20:30, Room E1) – Many ECS find it challenging to prioritise their mental wellbeing. Discuss with many other young scientist how to tackle this really important issue and maybe learn helpful tips how to improve your own wellbeing! 

Other useful skills to polish your career/CV:

Help! I’m presenting at a scientific conference (Mon, 14:00 –15:45, Room -2.62) – Your first conference talk might be daunting. Find out best practices and tips how to create a concise and clear conference talk.

How to share your research with citizens and why it’s so important (Mon, 14:00-15:45, Room -2.16) – Do you share your research with the public? Can you explain in simple matters? An important topic for researchers currently!

How to make the most of your PhD or postdoc experience for getting your next job in academia (Tue, 16:15 – 18:00, Room -2.85) – It’s never too early to plan your next career step.

How to convene and chair a session at the General Assembly (Tue, 08:30-10:15, Room -2.85) – Find out what it needs to convene a session of short course at EGU. You may be surprised, but you could to it next year if you liked,

How to peer-review? (Mon, 16:15 -18:00, Room -2.85) – After the end of a PhD (or sometimes even earlier!) you may be asked to peer-review journal contributions, but hardly anyone knows the process beforehand.

How to find funding and write a research grant (Tue, 10:45-12:30, Room -2.16) – One of the major tasks when you finish your PhDs. It might even be useful when writing applications for travel support etc.

Funding opportunities: ERC grants (Tue, 12:45-13:45, Room 0.14) – Find out more about these generous grants and how to successfully apply for them

How to apply for the Marie Sklodowska-Curie grants (Wed, 12:45-13:45, Room 0.14)

Balancing work and personal life as a scientist (Wed, 16:15 – 18:00, Room -2.85) – Find out how not to lose sight of your hobbies and personal life in a increasingly competitive academic environment. 

Other interesting events:

Academia is not the only route (Thu, 10:45-12:30, Room -2.16) – Are you finishing your degree and not overly excited by an academic future? Try this short course on exploring career alternatives both inside and outside academia

Games for Geoscience (Wed, 16:15-18:00 (Talks) in Room L8 and 14:00-15:45 (Posters), Hall X4) – Games are more fun than work! Learn more on how to use games for communication, outreach and much more. 

Unconscious bias (Wed, 12:45-13:45, Room -2.32) – Become aware of the obstacles that some of your colleagues face every day, and that might prevent them from doing the best science

Promoting and supporting equality of opportunities in geosciences (Thu, 14:00-18:00, Room E1) – Any of us should promote an open, equal opportunity working environment and this session promises some very interesting talk on common issues, solutions and initiatives.

What I’ve learned from teaching geosciences in prisons – (Thu, 14:00-15:45, Hall X4 – Poster) by GD ECS Phil Heron.

Rhyme Your Research (Tue, 14:00 – 15:45, Room -2.16) – Reveal the poet in you and explain your research in an interesting and unusual way!

This is just a small list of possible activities during EGU19, and I’m sure to have missed out many more. So keep your eyes and ears open for additional events and spread the word if you know anything of particular interest. Also make sure you follow the GD Blog, our social media (EGU GD Facebook page) and EGU Twitter, to keep updated with any more information during the week! The official hashtag is #EGU19. All the best for EGU and I am looking forward to meeting many of you there!

 

Demystifying the Peer-Review Process

Demystifying the Peer-Review Process

Adina Pusok

An important and inevitable aspect of being in academia is receiving a request to peer-review a paper. And much like the papers we write and submit, retaining structure and clarity for the review itself is important. This week Adina E. Pusok, Postdoctoral Researcher at Scripps Institution of Oceanography, UCSD, and our outgoing GD ECR representative, shares some detailed and helpful tips for writing a concise, efficient, and informative review. Do check out her very helpful Peer-review checklist PDF for download!

 

It is somewhat surprising that the peer-review process, a fundamental part of science (which prides itself on technical and objective methods), is usually left up to the individual reviewing scientist. Everyone agrees that there is little formal training in peer-reviewing, and many times it takes years until scientists become thorough and efficient reviewers (Zimmerman et al., 2011). Personally, I prefer to invest some of my time learning from other people’s experiences and best practices. For example, before my first review, I spent approximately two weeks researching material on how to deliver good reviews. But what are good reviews? And mostly, how does one write good reviews efficiently? In this blog post, I will attempt to synthesize some of the material I’ve come across, and share my personal guidelines that help me get through the peer-review process.

1. What is the peer-review process?

The peer-review process is in some ways like a legal trial. A judge (the editor) will take an informed and educated decision about the case (to publish/not to publish the manuscript in current form) based on the recommendations and arguments brought forward by lawyers (reviewers).

In reality, the journey of a manuscript (McPeek et al., 2009) through the peer-review process is as follows:

  1. The manuscript is submitted to a scientific journal.
  2. An editor reads the abstract/paper and decides whether it is suitable for potential publication at the journal.
  3. If approved, it is assigned to an associate editor who will handle the actual review process.
  4. The associate editor then compiles a list of potential reviewers, often partially based on recommendations from authors.
  5. Those reviewers are asked whether they would be willing to review the paper in a timely fashion.
  6. The reviewers then read the paper, consider the methods, data, analyses, and arguments, and write reviews containing their opinions about the paper, and whether the paper should be published in that journal.
  7. The associate editor reads the reviews, usually two or more, and may write a third review, and makes a recommendation to the editor.
  8. The editor then writes the authors a letter about the disposition of the paper.
  9. Depending on the outcome, the manuscript will have successfully exited this journey (accepted for publication), or will have to restart the process again (by resubmitting a modified version to the same or a new journal).

 

Basically, each manuscript submission depends on the work of volunteers (editors, reviewers) (McPeek et al., 2009). Indeed, peer-review, which lies at the cornerstone of advancing science, is primarily a volunteering exercise (also referred as “community work”). But this process is such a valuable mechanism to improve the quality and accuracy of scientific papers, that some people think the system would collapse without it, as there would be little control on what gets published.

What’s the purpose of it?

The goals of peer-review are clear: to ensure the accuracy and improve the quality of published literature through constructive criticism. Hames (2008) points out that every peer-review process should aim to:

  • Prevent the publication of bad work.
  • Verify that the research was conducted correctly, and there are no flaws in the design or methodology.
  • Ensure that the work is reported correctly and unambiguously, with acknowledgement to the existing literature.
  • Ensure that the results have been interpreted correctly and all possible interpretations were considered.
  • Ensure that the results are neither too preliminary nor too speculative.
  • Provide editors with evidence to make judgments as to whether articles meet the criteria for their particular publications.
  • Generally improve the quality and readability of a publication.
2. Who gets to do it?

The editor decides who should complete the review based on recommendations from the manuscript authors (nowadays, it’s a submission requirement for most journals), relevant literature cited in manuscript, or their own professional networks. The reviewers are generally considered experts in a given field (extensive peer-review and/or publishing experience), qualified (typically awarded with a Ph.D.) and able to perform reasonably impartial reviews. For example, because I am an early career scientist, I have been asked to perform reviews mostly on topics relating to my Ph.D. work (both the methods and the science).

3. What do you get out of it?

While the peer-review process seems more of an obligation for the greater good of science and society, it has its own perks (albeit not many), and one can benefit from them:

  • Whichever way you look at it, the peer-review process will improve your scientific work. On one hand, authors receive valuable feedback from experts in their community. On the other hand, reviewers get to reflect on what constitutes high-quality science and incorporate lessons learned from reviewing into their own work.
  • Following the above point, reviewing does make you a better writer. You learn so many lessons from reading excellent to bad manuscripts, and in particular, you learn how to/not to write. It is very frustrating when you struggle with someone else’s unclear explanations or weak arguments. In my experience, that definitely makes you promise yourself to avoid those errors.
  • Reviewing trains your critical thinking, impartial judgment, and diplomatic skills. A review is not useful if it is not civil and contains personal or destructive criticism. In general, you learn to clearly argument your points and be diplomatic about the strengths and weaknesses of a paper.
  • You get to see the latest work before it is even published. Do make sure, though, that you respect the integrity of the review process and do not communicate any aspect of the paper to other people. In any case, this helps you stay on top of your field or expand/learn new science.
  • It does look good on your CV! Everyone agrees that community service (such as reviewing) is a positive for those aspiring for an academic career.
  • Most editors are senior scientists, and by entering the reviewers’ network, you become known. Better yet?! You become known as an expert in a certain field. Fortunately (or unfortunately), since academia relies heavily on prestige and reputation, that will pay off in the longer term.
  • Some journals will provide credit for your review, by acknowledging all reviewers once a year, or by awarding exceptional community service at meetings. While this is great for some, many scientists feel it is insufficient for the amount of work involved in reviews. Therefore, in recent years, it is possible to keep a general record of your reviews using ORCID and/or Publons (pay attention that only the journal and the year of each review is made public). This allows scientists to have something of a review index (complementing the usual publication index – e.g., Google Scholar).
4. How to undertake a peer-review?

Before I even started reviewing, I was somewhat familiar with what reviews looked like – I had already received them for my own submitted research papers. One of the first things I noticed is that each of the reviews had different styles: annotated PDFs or text files with line numbers, brief and not so useful/detailed reviews, short or long reviews etc. Since scientists receive little peer-review training, they are also likely to develop their own review style with time and experience. In principle, the style should not matter as long at the review is thorough, clear, and constructive.

There are many ways to complete a review, but just like writing an article, if you have a plan and structure, the entire process becomes easier and even more enjoyable. Moreover, establishing some good practices will ensure a robust review done in a timely manner. Plus, if you are like me (writing is not my favourite activity), you want to find ways to get the job done, as fast as possible and return to more exciting tasks. I find that checklists come in useful, whether it is about academic writing, presentations or reviewing.

Therefore, what I will attempt in this blog is to create a Peer-Review Checklist that anyone can download as a PDF and help them navigate through the review process. It is a checklist I initially created for my own use, and I hope these tips in turn are relevant for first-time/early reviewers that are still in search of their styles. The checklist may also be useful to other experienced reviewers as a refresher. I would like to note that this is a suggested checklist and workflow, and depending on the journal or field, some elements may be different or missing. People should adapt the checklist to suit their needs, personal style, and the journal’s guidelines. I am also happy to receive suggestions (comments below/email), in order to improve the checklist over time.

Before I present the checklist in more detail, I want to highlight some resources that can help anyone improve their reviews:

  • Talk to colleagues, advisors, and friends about the reviewing process.
  • Pay attention to the reviews of your own papers. I actually modeled mine after one of the most constructive reviews I received.
  • Check journal guidelines. Many journals have extensive and good advice available online.
  • Published material (the most useful material that I found, especially Nicholas and Gordon, 2011, Stiller-Reeve et al., 2018a,b, and McPeek et al., 2009):
Peer-Review Workflow and Checklist

This checklist has been compiled from the advice of various articles and guides, and personal preferences. The aim is to give early reviewers a quick workflow of questions and tasks (that you can mark as completed) for any manuscript review. By following all the points, anyone can produce a constructive and thorough review in a timely manner.

Step 1: Pre-Read – Received an invitation to review

✓ Read abstract.

✓ Appropriate expertise.
Does my area of expertise and experience qualify me to critically evaluate the manuscript? Sometimes it will fit exactly with your expertise, whereas other times it will only just brush your field. One instance, I accepted a review that implemented a technical novelty in a method that I was familiar with. I decided it was still largely within my expertise, but I took the opportunity to learn something new. I made sure I went over the background studies, until I was comfortable asking questions and clarifying points. If you feel less confident, and your expertise allows you to comment meaningfully only on key sections of the paper, you can offer to review these areas and let the editor know you cannot comment on other aspects outside your expertise.

✓ Conflict of interest.
Can I provide a fair and unbiased review of this work? Am I able to evaluate the manuscript with an open mind, without being either negatively/positively predisposed? Check the journal’s guidelines for more specific guidance on avoiding conflicts of interest.

✓ Time and deadline.
Do I have time to write a complete review? Most journals suggest a timeline of a couple of weeks from the moment the invitation was accepted (usually 2-4 weeks). While this may seem sufficient time to return the review, most scientists have a large workload, and end up allowing only a few days for the review. Moreover, it can take more than 8 hours to provide a thoughtful, thorough, and well-referenced review (can depend on the paper type of course, so also pay attention to that). If you are unable to meet the deadline, contact the journal so that the editors can determine the appropriate course of action (some extensions can be granted at the discretion of the editors).

✓ Check journal guidelines and adjust your workflow.
It is better to do this early on in the review.

✓ Respond as soon as possible: Accept/Decline.
Explain to editor the reason for decline, and offer, if possible, suggestions for other reviewers.

Step 2: First Read – Gaining an overview

✓ Set up the structure of review
Prepare a document (I prefer to have a simple text file at hand) containing the following structure of the review:

R0. Review details
R1. Introduction (3 paragraphs)
R2. Major issues (numbered items)
R3. Minor issues (indicate line, figure, table numbers)
R4. Other suggestions (regarding supplementary material, etc.)
Notes (not included in final review)

✓ Read the entire paper. Take notes as you go
The first reading is to get an overall impression of the paper: motivation, approach, overview of results, and conclusions. Take some notes as you go. I usually like to print a copy and make annotations as I go along. However, don’t worry too much with corrections, spelling, punctuation, or references. It’s supposed to be a ‘casual’ reading (kidding).It might be a challenge, but at this point do your best to understand the paper. Some papers read (and are written) better than others, and it would be a shame to miss an interesting study, just because of language barriers. And it is perfectly normal (apparently!) to struggle reading a scientific article with “ultra-congested and aggressively bland” text. This article might help and amuse you: the 10 Stages of Reading a Scientific Paper.

✓ Go through all figures and tables
Do they complement the approach, results section, and conclusions?

✓ Readability
Sometimes it cannot be helped but to ask: is the English/writing so bad that you can’t understand the arguments? If the manuscript needs copyediting by a proficient English speaker before you can evaluate it on its scientific merits, it is legitimate to make such a suggestion to the editor at this stage. You can point out that you cannot give the paper a fair review in its current form, and suggest the paper to be withdrawn from review until the English is improved.

✓ Identify goals, method, findings, and relevance
The questions below might help:

  • What is the main question addressed by the research?
  • Is this question interesting and important to the field of study? How, specifically, will the paper contribute to the science?
  • Do the Abstract and Introduction clearly identify the need for this research, and its relevance?
  • Does the Method target the main question(s) appropriately?
  • Are the Results presented clearly and logically, and are they justified by the data provided?
  • Are the figures clear and fully described?
  • Do the Conclusions justifiably respond to the main questions posed by the author(s) in the Introduction?
  • Is the paper within the scope of the journal?
  • Is the paper potentially publishable based on its contribution to the field?

✓  Write introductory paragraphs (Section R1 – first 2 paragraphs) [“The study investigates/uses/finds/contributes”]
Answering the above questions will help you start the written review. In general, the most helpful review to everyone is one that first provides an overall summary of the main contributions of the paper and its appropriateness for the journal, and suggests what major items should be addressed in revision. This summary can also help you reveal what this paper is really about, if you weren’t sure until now. Or you might end up, writing back “It was difficult to understand the precise point(s) the authors were trying to make.”

The first paragraph should state the main question addressed by the research, and summarize the goals, approaches, and conclusions of the paper. Try writing one sentence for each of these points. The second paragraph of the review should provide a conceptual overview of the contribution of the paper to the journal. Some people suggest trying to also include here the positive aspects in which the paper succeeds, since there is enough space for negative aspects for the remainder of the review. The authors will have a sense of what they have done well, and will not be too discouraged.

✓  Evaluate whether the manuscript is publishable/or not (Section R1 – 3rd paragraph)

[“I recommend the manuscript not/to be published in Journal X with minor/major modifications, and I provide below the reason for my decision and some comments that are necessary to address….”]

You have three decision options: the manuscript is/has

  1. publishable in principle -> Continue review to Step 3: Second Read.
  2. major flaws, but addressable -> Return manuscript to authors for corrections, but document and substantiate the flaws, indicate willingness to provide full review if authors address them (continuing to Step 3: Second Read may still be helpful to reply to editor/authors).
  3. fatally flawed/unsuitable -> Reject, but document and substantiate why. You consider the manuscript is flawed in a way that cannot be fixed and/or is unsuitable for publication in the target journal (high impact journals like Nature or Science reject most submissions solely based on the suitability of study to the journal).

Some manuscripts can have flaws that cannot be overlooked or improved easily. Examples of such fatal flaws might include drawing a conclusion that is contravened by the author’s own statistical evidence, the use of a discredited method, or ignoring a process that is known to have a strong influence on the system under study. Whatever the decision, remember to carefully explain your reasoning and provide clear evidence for it (including citations from other scientific publications).

Assuming there is no fatal flaw, you can continue to a second reading. Personally, I like to let the paper sit for a couple of days after the First Read, and let my mind digest the information. It will be surprising, but you allow some time for your brain to synthesize the major aspects (strengths and weaknesses) of the paper, and you want to focus primarily on those aspects in the next stage.

Step 3: Second Read – The science (major/minor points)

✓  Take detailed Notes (end of review file) indicating section, line, figure, and table numbers

Read the manuscript in detail from start to finish. Pay attention to assumptions, methods, underlying theoretical frameworks, and the conclusions drawn and how well they are supported. Refer to figures and tables when referenced in the text, making sure that the text and the graphics support rather than repeat each other, use your careful study of the figures at the end of the first reading to avoid too much disruption to the flow of your assessment.

I have found it useful to dump in the review file all the comments I have (brainstorming as I re-read the manuscript), including specific comments, thoughts or issues I want to return to. Indicate the line or figure numbers for all comments. There is a reason why most journals ask authors to add numbers to their submissions: to be specific about various comments and suggestions. For example, “line 189 contradicts the statement in line 20”, “paragraph 45-52 is unclear and convoluted, should be rephrased”, “Figure 2a needs X,Y labels”, etc. Plus, most of the review will have the important details written by the time you are done with the second reading. Another tip, it helps to classify your comments as major or minor flaws. Major flaws will need considerable time to explain or correct.

Note: some journals allow reviews as annotated PDFs – I found they are not that helpful because in the Reply-to-reviewers as manuscript author, I had to transcribe many of those comments again. Plus, a single read of the paper might not give enough insight into the strengths/weaknesses.

A sub-checklist:

  • Check every section individually (my preferred order): Introduction, Methods, Results, Discussion, Conclusions, Abstract, Other (e.g., Key points, Appendices). Make notes also on structure and flow of arguments.
  • Check method (i.e., equations, the experimental setup, data collection, details needed for reproducing results, and if that is not possible, is it stated why?).
  • Check all figures and tables, so that you understand all units, axes, and symbols. Do the figures reflect the main text?
  • Check References/referencing is done correctly.
  • Check any supplementary material.
  • Remind yourself the journal’s guidelines. Most importantly, does the manuscript comply with the journal’s data policy and best practices?

✓  Identify major and minor points (Sections R2 and R3)

Now it’s time to organize all those notes and comments. I usually sort them in 2 categories: major and minor issues (Sections R2, R3 of review). In general, the minor issues (e.g., line 21 – missing reference to the referred study, line 32 – sentence not clear, line 56 – typos) do not need further work at this stage.

Major points, on the other hand, require some work. First, organize major points clearly and logically, using separate numbered paragraphs or bullets to make each point clearly stand out. Make use of your numbered notes to provide evidence. It is the reviewer’s obligation to point out the weaknesses in the underlying science. If the methods are suspect, or if the authors over-interpret the data, or if they overlook important implications of their work, or more analyses are needed to support the conclusions, you should point that out as major points.

Is it possible to have too many major points? Could it be because they are not that major (overestimation of importance), or are they really major and cannot be overlooked? This might make you re-evaluate the review (major/minor, largely flawed). In general, I was not given more/found more than 10 major points in a manuscript, but exceptions can happen. Very importantly, try to advise the authors with concrete, actionable ways to address the problems.

✓ Add Other Points (Section R4 – Optional)

If there is anything else to add to the review, neither fitting the category of major nor minor points, such as suggestions for future work, add them at the end of review. If you have no further comments, it’s fine to leave this section empty.

Step 4: Final Read – The writing and formulation

Briefly read through the paper a third time, looking for organizational issues, and finalize the review.

✓ Check organization and flow of arguments

While you probably already noted down many of such issues (because if the manuscript is poorly written, then the arguments will often not make sense either), it’s still a good idea to quickly go over the writing and presentation (section headings, details of language and grammar). Suggest ways how to make the story more cohesive and easily reasoned.

However, was the paper hard to read because the paragraphs did not flow together? Did the authors use excessive and confusing acronyms or jargon? In these cases, I actually include improving the structure of the manuscript as a major point. However, do not feel obligated to catch every typo, missing reference, and awkward phrase – your scientific assessment of the paper is more important.

✓ Read and polish your own review
Read the review carefully, and preferably aloud, imagining you are the editor or the authors of the study. What’s the tone of your arguments? How would you feel receiving it back as the author? Will you find the review helpful and constructive? Or fair? This will draw your attention to how your criticisms might sound to the ears of the authors. Make sure to keep the tone civil and include both positive and negative comments.

✓ Upload your review using the link provided
I usually copy and paste my review (Sections R1-R4) in the provided boxes by the journal, or upload the polished review file.

✓ Answer specific questions regarding the manuscript and its presentationYou will probably also be asked specific questions or rate the manuscript on various attributes (answers in drop-down selections).

✓ Remarks to the editors
Any issues that the editors should be aware of can be indicated separately in Remarks to the editors, which remain confidential.

✓ Submit review to editor
You are done! You will probably hear back from the editor about their decision to accept or reject the manuscript. Important to understand, is that the editors take the final decision. Your role was only advisory in the whole process. However, you may be asked to review another version of the manuscript to assess whether the manuscript has been modified sufficiently in response to reviewers’ comments.

5. Etiquette of reviewing

I hope by now you have a clear idea of what constitutes the peer-review process and how to perform a review. Again, there are many ways how to undertake a review, but maybe you will find the checklist useful. It most surely requires considerable time and effort, but the checklist allows me to be confident that I gave my best consideration for the work submitted. By also ticking off tasks, I can perform the review in an efficient way, without worrying that I forgot something.

However, I am aware that we tend to be over-critical of other peoples work (and the workflow proposed here is quite lengthy). I’ve heard a couple of times the comment that “young scientists provide very lengthy and harsh reviews”. That has some grain of truth in it, as from a desire of being thorough, we might ask for extra-work for revisions that go beyond the scope of the manuscript or resources (time, material, etc.). We need to be aware of that, but at the same time invite authors to discuss potential avenues for the work.

What I will discuss next, is the etiquette of reviewing: what to do/not to do, fairness of reviews, providing/receiving criticism, and the Golden Rule of reviewing. As you will see below, they are interconnected with each other.

5.1 What to do/not to do when peer-reviewing

Top 3 To do:

– the review does not have to be long, but make sure you did a thorough and fair review, as you would want others to do it in return.

– be critical, argumentative, and straightforward: explain the problem, why it’s a problem, and suggest a solution.

– finish before the agreed upon deadline.

Top 3 Don’t do:

– be sarcastic, dismissive or other such tones. The review should be constructive and not offensive.

– be biased or let personal prejudices influence your assessment of the manuscript (e.g., poor English, excessive self-citations). In such cases, it’s better to decline to review and explain potential conflict of interest.

– write a too short review (even if it’s a great study). The authors might be happy to hear that, but the editor will not find it useful.

5.2 Working towards a transparent and fair peer-review process 

Scientific peer-review is regularly criticized as being ineffective, broken or unfair. However, journals are generally committed to take active steps in order to ensure the fairness of the process. For example, most journals have clear ethical guidelines (i.e., AGU, EGU), and all participants in the review process are expected to uphold these guidelines.

While most of the review interaction happens privately between the authors-editors-reviewers, some journals (e.g., EGU journals, Nature Communications) have taken a step forward to make the peer review process more transparent, such that manuscript authors are given the option to publish the peer review history of their paper. This is great for making the process more open and fair! However, making things public can, in some cases, create unethical practices. For example, to ensure the impartiality and confidentiality of the peer review process, you should not discuss your review of the paper with anyone before or after publication. Also, apparently revealing yourself as a reviewer to the author or authors after review might create the wrong impression, as if you’re asking for favourable treatment in the future.

This last aspect brings the questions: “Should we reveal ourselves as reviewers or not?” and “Anonymous or signed review?” (see this perspective and another one). A senior editor and the author of Geoverbiage, Judy Totman Parrish, says that whether you sign your reviews is a personal decision, and that she has always signed her reviews in order to ensure the transparency, and the free exchange of ideas. She also says that she’s never experienced any backlash for any of the reviews she wrote.

I write my reviews anonymously, for exactly the same goal as above: to work towards a fair peer-review process. I find that there are many instances in which biases can form during the peer-review process (i.e., based on gender, age, nationality, but also experience, affiliation, or even prestige/prominent names) (see this article). My personal take on these issues, is that I believe reviews should be double-anonymous (authors do not know who the reviewers are, and reviewers do not know who the authors are), and the review history should be made public. I think this would reduce biases (probably not completely, as some authors/research groups can still be identified by the work submitted), while a transparent review history could ensure the fairness and civility of the review process. Also, with the rise of review statistics (ORCID and/or Publons), one can still be acknowledged for the work performed, without having to sign their names. This might not be possible in some fields (i.e., medicine or other fields where ethical guidelines are stricter), but in geophysics and geodynamics this shouldn’t be a problem.

5.3 Providing and taking criticism

This section might seem out of place for this blog post, but imagine for a moment that you are an author, and you’ve just put a lot of work to write the best paper so far. Your co-authors have read and re-read the paper, generating multiple improved versions with their comments. You finally submit the manuscript for review and, after a seemingly a long amount of time, you get the reviews back. Would you take the delivered message(s) as intended, or be hurt by it? With time you learn to not take things personally, but it’s unavoidable not to feel the tiniest bit affected by major criticism for the study you’ve worked so hard on.

The peer-review process puts you at the other end of writing papers. Therefore, I think scientists need to try their best to provide and receive constructive criticism, and identify and avoid destructive criticism (usually, directed at a person). What helps is to ask yourself: “Is it fair point? Could I use it to make a better version of the manuscript?”. If the answer is ‘yes’, then take the comment and use it to improve your work.

5.4 The Golden Rule

I would like to finish with the Golden Rule of reviewing. In their interesting read, McPeek et al. (2009) suggests reviewers to perform reviews with this in mind: “Review for others as you would have others review for you”.

I think as a more general rule, we can use some ancient wisdom: “Don’t do to others what you wouldn’t want done to yourself!”. It goes for reviewing and many aspects of life.

References:

Hames, I., (2008), Peer review and manuscript management in scientific journals: guidelines for good practice. John Wiley & Sons, https://onlinelibrary.wiley.com/doi/book/10.1002/9780470750803

McPeek, M.A., DeAngelis, D.L., Shaw, R.G., Moore, A.J., Rausher, M.D., Strong, D.R., Ellison, A.M., Barrett, L., Rieseberg, L., Breed, M.D., Sullivan, J., Osenberg, C.W., Holyoak, M., and Elgar, M.A., (2009), The Golden Rule of Reviewing, The American Naturalist, Vol. 173, No. 5, 155-158, https://www.journals.uchicago.edu/doi/10.1086/598847

Nicholas, K.A., and Gordon, W. (2011), A quick guide to Writing a solid peer review, EOS, Vol. 92, No. 28,  https://sites.agu.org/publications/files/2013/01/PeerReview_Guide.pdf

Stiller-Reeve et al. (2018), A peer review process guide, https://www.scisnack.com/wp-content/uploads/2018/10/A-Peer-Review-Process-Guide.pdf

Stiller-Reeve et al. (2018), How to write a thorough peer review, Nature, doi: 10.1038/d41586-018-06991-0,nhttps://www.nature.com/articles/d41586-018-06991-0

Zimmerman, N., R. Salguero-Gomez, and J. Ramos (2011), The next generation of peer reviewing, Front. Ecol. Environ., 9(4), 199, doi:10.1890/1540-9295-9.4.199, https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/1540-9295-9.4.199