Biophysical interactions in the plankton: A cross-scale review

In plankton ecology, biological and physical dynamics are coupled, structuring how plankton interact with their environment and other organisms. This interdisciplinary field has progressed considerably over the recent past, due in large part to advances in technology that have improved our ability to observe plankton and their fluid environment simultaneously across multiple scales. Recent research has demonstrated that fluid flow interacting with plankton behavior can drive many planktonic processes and spatial patterns. Moreover, evidence now suggests that plankton behavior can significantly affect ocean physics. Biophysical processes relevant to plankton ecology span a range of scales; for example, microscale turbulence influences planktonic growth and grazing at millimeter scales, whereas features such as fronts and eddies can shape larger-scale plankton distributions. Most research in this field focuses on specific processes and thus is limited to a narrow range of spatial scales. However, biophysical interactions are intimately connected across scales, since processes at a given scale can have implications at much larger and smaller scales; thus, a cross-scale perspective on how biological and physical dynamics interact is essential for a comprehensive understanding of the field. Here, we present a review of biophysical interactions in the plankton across multiple scales, emphasizing new findings over recent decades and highlighting opportunities for cross-scale comparisons. By investigating feedbacks and interactions between processes at different scales, we aim to build cross-scale intuition about biophysical planktonic processes and provide insights for future directions in the field.