I was invited to give a seminar on 10/14/20 for the Women in Network Science Seminar series (WiNS seminars) hosted by a fellow woman in network science and wonderful human, Alice Schwarze. The WiNS seminar series is one of the few good things to come out of this pandemic. If you missed my seminar, check out the recording and abstract below!

ABSTRACT: As coral reefs struggle to persist under a multitude of threats, understanding the resistance and resilience of these complex systems is a central goal of coral reef biology and ecology. Different coral species associate with different species of symbiotic algae (Symbiodiniaceae), creating a complex network of symbiotic associations on a reef. This symbiotic relationship is vulnerable to increasing temperatures. Coral bleaching is the breakdown of the association between the coral host and its endosymbiotic algae in response to stressful temperatures. We analyzed a global network of coral-symbiont associations for resistance to temperature stress and robustness to various perturbations. Our novel bleaching model determined resistance of the networks to increasing temperature by removing links when the environmental temperature surpassed their weight, a temperature threshold for individual host-symbiont pairs based on known physiological responses. Ecological robustness, defined by how much perturbation is needed to decrease the number of nodes by 50%, was determined for multiple removal models that considered traits of the hosts, symbionts, and their associations. We show that the global network of associations between corals and Symbiodiniaceae and its distribution of thermal tolerances are non-random, and the evolution of this architecture has led to higher sensitivity to environmental perturbations. By limiting our spatial scale and expanding our temporal scale, we can start to answer questions about reef resilience. To do this, I repetitively monitored and sampled a coral-Symbiodiniaceae network in Bocas del Toro, Panama from January 2017 to January 2018, during which the reef experienced two high-temperature bleaching events. We explored how Symbiodiniaceae communities varied across host species, depth, and time. Temporal networks of the symbiotic associations were used to assess differences in association patterns that led to structural and/or functional resilience to repeat heat stress events. I define structural resilience as a system’s ability to either resist changing the structure of associations or return to the initial structure after a disturbance. Functional resilience is a system’s ability to recover in relation to its health and function, but it may also undergo structural changes during that recovery. Structures of Symbiodiniaceae co-occurrence networks and coral-symbiont networks varied through time indicating that on a reef scale, the coral-symbiont associations responded to changing environmental conditions.