Spatial patterns in complex systems often reflect discernible interactions between the system's components. We investigate the causes and consequences of spatial patterning as observed in satellite and drone images of various marine and terrestrial systems.
Small scale phytoplankton patchiness in the southeastern Mediterranean
Phytoplankton are a diverse assemblage of photosynthetic microorganisms, which form the base of the marine food web and drive approximately half of the global annual net primary production. The spatial organization of these ubiquitous organisms influences the marine ecosystem and Earth's climate system. We currently study the spatial patterning of phytoplankton in the highly oligotrophic waters of the southeastern Mediterranean Sea, focusing on the processes underlying small scale (<10km) variations in phytoplankton community structure.
On the left: Surface chlorophyll concentrations in the southeastern Mediterranean, obtained from Copernicus multi-satellite ocean color product (https://marine.copernicus.eu/) on 8 March 2020. We investigate the processes underlying the observed patterning of the chlorophyll field, and their association with variation in the structure of the regional plankton ecosystem.
Patterns of exposure to SARS-CoV-2 carriers
Motivated by the worldwide efforts to understand different aspects of the COVID-19 disease, in a recent work conducted with Doron Chelouche and Gabriel Cotlier, we tested the hypothesis that patterns of spatial heterogeneity, or patchiness, in urban landscape impose spatially varying constraints which may affect the potential for COVID-19 spread. By comparing results from 17,250 epidemiological investigations carried out during the early stages of the disease outbreak in Israel, with characteristics of urban landscape as derived from satellite images, We find that exposure to coronavirus-2 (SARS-CoV-2, the virus that causes COVID-19) carriers was significantly more likely to occur in “patchy” parts of the city, where the urban landscape is characterized by high levels of spatial heterogeneity at relatively small scales (~10-100m).
On the right: Locations of reported exposures to SARS-COV-2 carriers from results of epidemiological investigations (red dots), overlaid on values of landscape patchiness index (LPI, a measure to the contribution of small scales to the total variance in a given grid cell) in the Gush Dan district, Israel.