Abstract. Early-career scientists (ECSs) are a large part of the workforce in science. While they produce new scientific knowledge that they share in publications, they are rarely invited to participate in the peer-review process. Barriers to the participation of ECSs as peer reviewers include, among other things, their lack of visibility to editors, inexperience in the review process and lack of confidence in their scientific knowledge. Participation of ECSs in group reviews, e.g. for regional or global assessment reports, provides an opportunity for ECSs to advance their skill set and to contribute to policy-relevant products. Here, we present the outcomes of a group peer review of the First Order Draft of the Intergovernmental Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC). Overall, PhD students spent more time on the review than those further advanced in their careers and provided a similar proportion of substantive comments. After the review, participants reported feeling more confident in their skills, and 86 % were interested in reviewing individually. By soliciting and including ECSs in the peer-review process, the scientific community would not only reduce the burden carried by more established scientists but also permit their successors to develop important professional skills relevant to advancing climate science and influencing policy.

To understand the mechanisms leading to coexistence and exclusion, it is essential to establish information on the nutritional needs of species. We focused on the frequently coexisting Pseudo-nitzschia species, P. delicatissima and P. galaxiae, capable of forming blooms and producing domoic acid. We employed monoculture experiments to determine growth kinetic parameters important for understanding resource use (i.e. maximum specific growth rate, half-saturation coefficients for growth and cell quotas), and we coupled mixed-culture experiments and numerical modelling to explore the role of resource competition relative to unknown factors, such as allelopathy. Experimental results showed that both species had a high requirement for nitrogen (N) and low requirement for phosphorus (P), consistent with field observations of Pseudo-nitzschia blooms in N-rich conditions. The model accurately predicted the outcome of competition; P. galaxiae outcompeted P. delicatissima when considering only resource competition, but the population trajectories were better predicted when allelopathic effects were added. Since the competitive exclusion of P. delicatissima by P. galaxiae in our laboratory experiments is not consistent with observations of coexistence in the natural environment, the model was further modified to explore realistic ranges of population loss factors, such as sinking, demonstrating how coexistence is possible when these are considered.

Abstract. A simplified model, representing the dynamics of marine organic particles in a given size range experiencing coagulation and fragmentation reactions is developed. The framework is based on a discrete size spectrum on which reactions act to exchange properties between different particle sizes. The reactions are prescribed according to triplets interactions. Coagulation combines two particle sizes to yield a third one, while fragmentation breaks a given particle size into two (i.e. the inverse of the coagulation reaction). The complete set of reactions is given by all the permutations of two particle sizes associated with a third one. Since, by design, some reactions yield particle sizes that are outside the resolved size range of the spectrum, a closure is developed to take into account this unresolved range and satisfy global constraints such as mass conservation. In order to minimize the number of tracers required to apply this model to an Ocean General Circulation Model focus is placed on the robustness of the model to the particle size resolution. Thus, numerical experiments were designed to study the dependence of the results on i) the number of particle size bins used to discretize a given size range (i.e. the resolution) and ii) the type of discretization (i.e. linear vs nonlinear). The results demonstrate that in a linearly size discretized configuration, the model is independent of the resolution. However, important biases are observed in a nonlinear discretization. A first attempt to mitigate the effect of nonlinearity of the size spectrum is then presented and shows significant improvement in reducing the observed biases.

<p><strong>Abstract.</strong> Early Career Scientists (ECS) are a large part of the work force in science. While they produce new scientific knowledge that they share in publications, they are rarely invited to participate in the peer-review process. Barriers to the participation of ECS as peer-reviewers include, among others, their lack of visibility to editors, inexperience in the review process and lack of confidence in their scientific knowledge. Participation of ECS in group reviews, e.g. for assessment reports, provides an opportunity for ECS to advance their skill set and to contribute to policy relevant products. Here, we present the outcomes of a group peer-review of the first order draft of the Intergovernmental Panel on Climate Change Special Report on Ocean and Cryosphere in a Changing Climate (IPCC SROCC). Overall, PhD students spent more time on the review than those further advanced in their careers, and provided a similar proportion of substantive comments. After the review, participants reported feeling more confident about their skills, and 86 % were interested in reviewing individually. By soliciting and including ECS in the peer-review process, the scientific community would not only reduce the burden carried by more established scientists, but permit their successors to develop important professional skills relevant to advancing climate science and influencing policy.</p>

A simplified model, representing the dynamics of marine organic particles in a given size range experiencing coagulation and fragmentation reactions is developed. The framework is based on a discrete size spectrum on which reactions act to exchange properties between different particle sizes. The reactions are prescribed according to triplets interactions. Coagulation combines two particle sizes to yield a third one, while fragmentation breaks a given particle size into two (i.e. the inverse of the coagulation reaction). The complete set of reactions is given by all the permutations of two particle sizes associated with a third one. Since, by design, some reactions yield particle sizes that are outside the resolved size range of the spectrum, a closure is developed to take into account this unresolved range and satisfy global constraints such as mass conservation. In order to minimize the number of tracers required to apply this model to an Ocean General Circulation Model focus is placed on the robustness of the model to the particle size resolution. Thus, numerical experiments were designed to study the dependence of the results on i) the number of particle size bins used to discretize a given size range (i.e. the resolution) and ii) the type of discretization (i.e. linear vs nonlinear). The results demonstrate that in a linearly size discretized configuration, the model is independent of the resolution. However, important biases are observed in a nonlinear discretization. A first attempt to mitigate the effect of nonlinearity of the size spectrum is then presented and shows significant improvement in reducing the observed biases.