Temporal and Spatial Scales of Correlation in Marine Phytoplankton Communities

Abstract

Ocean circulation shapes marine phytoplankton communities by setting environmental conditions and dispersing organisms. In addition, processes acting on the water column (e.g., heat fluxes and mixing) affect the community structure by modulating environmental variables that determine in situ growth and loss rates. Understanding the scales over which phytoplankton communities vary in time and space is key to elucidate the relative contributions of local processes and ocean circulation on phytoplankton distributions. Using a global ocean ecosystem model, we quantify temporal and spatial correlation scales for phytoplankton phenotypes with diverse functional traits and cell sizes. Through this analysis, we address these questions: (1) Over what timescales do perturbations in phytoplankton populations persist? and (2) over what distances are variations in phytoplankton populations synchronous? We find that correlation timescales are short in regions of strong currents, such as the Gulf Stream and Antarctic Circumpolar Current. Conversely, in the subtropical gyres, phytoplankton population anomalies persist for relatively long periods. Spatial correlation length scales are elongated near ocean fronts and narrow boundary currents, reflecting flow paths and frontal patterns. In contrast, we find nearly isotropic spatial correlation fields where current speeds are small, or where mixing acts roughly equally in all directions. Phytoplankton timescales and length scales also vary coherently with phytoplankton body size. In addition to aiding understanding of phytoplankton population dynamics, our results provide global insights to guide the design of biological ocean observing networks and to better interpret data collected at long-term monitoring stations.Plain Language Summary Using a global model of the marine planktonic ecosystem, we quantify the temporal and spatial correlation scales of diverse types of phytoplankton. The timescales reflect the persistence of anomalies in time and the stability of the planktonic system. The spatial scales measure over what distances variations in phytoplankton populations are synchronous. We find that timescales and length scales vary with cell size and that global patterns of correlation are shaped by ocean currents. These results provide valuable insights for the design of ocean observing systems with a unique ecological perspective. We also discuss how regional differences in phytoplankton community correlation scales are relevant for interpreting data collected at long-term monitoring stations.

Elucidating ecological complexity: Unsupervised learning determines global marine eco-provinces

“…For this study, the 20-year mean of these outputs was used as the input for the eco-provinces. Distribution of Chl, plankton biomass, and nutrient concentrations, as well as distributions of functional groups compare well with satellite and in situ observations [see (2,44), note S1, and figs. S1 to S3].…”

“…Parameters influencing phytoplankton growth, grazing, and sinking are related to size, with specific differences between the six phytoplankton functional groups (32). Results from this 51 plankton component of the model have been used in several recent studies (42)(43)(44), though in a different physical framework.…”

Cells of matter and life – towards understanding the internal structure and spatial patchiness of particles and plankton distribution in the Arctic fjords

“…CC BY 4.0 License. between different size classes of those (Kuhn et al, 2019;Trudnowska et al, 2016), which may explain why we observed different distribution patterns of various size fractions (e.g. the Pico fraction was mostly confined to the upper few meters while having wide horizontal distribution, whereas the Micro and Small fraction patches extended frequently over wide vertical ranges, but had much smaller horizontal range).…”

“…To make matters more complicated, the dominating mechanisms vary depending on the scale, location or time of the year (Martin, 2003), e.g., the relative importance of the biotic processes increases inversely with scale (Pinel-Alloul, 1995), because the physical processes act naturally at different timescales than plankton growth and activity (Mahadevan, 2016). Also the local processes and ocean circulation operate on very different scales, making it extremely difficult to elucidate their relative contributions on particles and plankton distributions (Kuhn et al, 2019). In the case of the patches analysed in this study, the local environmental variables were the most crucial in the case of the fjord, where smaller spatial scale was investigated (Isfjorden), whereas the spatial effect was privileged when the larger distance and thus wider spectrum of environments was considered (Kongsfjorden).…”

Cutting Through the Noise: Bacterial Chemotaxis in Marine Microenvironments

“…Yet, phytoplankton exudates and other dissolved organic matter exist as complex mixtures of compounds which differ in their abundance, diffusivity and propensity to elicit chemotaxis (Davis and Benner, 2007;Duursma and Dawson, 2011). Emerging analytical methods of characterizing chemical microenvironments, exudation rates and nutrient exchanges (Wessel et al, 2013) will further inform models for microbial motion (Keller and Segel, 1970;Jackson, 1987;Bray et al, 2007;Desai et al, 2019) through to ocean-scale dynamics of microbial populations (Barton et al, 2010;Worden et al, 2015;Kuhn et al, 2019).…”