Abstract
<jats:title>Abstract</jats:title> <jats:p>Algae are often at the base of food webs in aquatic and marine environments and are responsible for more than half of the global primary production. They now play an increasingly important role in global aquaculture. Yet, understanding of algal evolutionary ecology is limited compared to other ecologically and economically important organisms. One contributing factor to a lack of synthesis is the overwhelming diversity encompassed by the term “algae”—ranging from cyanobacteria to giant kelps. The authors survey the macroalgal holobiont and what is known about the organisms that could contribute to algal disease in both natural populations and cultivated macroalgae. They define important terms, including what “disease” means from a macroalgal perspective. They then provide an overview of the diversity of macroalgal life cycles and life-history traits that affect the ability to study their population structure. It is from aquaculture and economically important species in nature that the most insight into macroalgal disease has been gained. Finally, the authors summarize their overview of macroalgal disease ecology with a call to action of important next steps to increasing the understanding of macroalgal evolutionary ecology. They highlight the large gaps in the understanding of basic and fundamental features of macroalgal biology that greatly restrict the ability to understand how macroalgae will respond to climate change and under artificial selection in farms.</jats:p>