A global photic-ocean plankton ecological network predicts distinct vulnerabilities to environmental change across marine biomes. Marine plankton form comp lex communities of interacting organisms at the base of the food web, which sustain oceanic biogeochemical cycles and help regulate climate. Although global surveys are sta rting to reveal ecological drivers underlying planktonic community structure and predicted climate change responses, it is unclear how community-scale species interactions will be affected by climate change. Here, we leveraged Tara Oceans sampling to infer a global ocean cross-domain plankton co-occurrence network—the community interactome—an d used niche modeling to assess its vulnerabilities to environmental change. Globally, this revealed a plankton interactome self-organized latitudinally into marine biomes (Trades, Westerlies, Polar) and more connected poleward. Integrated niche modeling revealed biome-specific community interactome responses to environmental change and forec asted the most affected lineages for each community. These results provide baseline approaches to assess community structure and organismal interactions under climate scena rios while identifying plausible plankton bioindicators for ocean monitoring of climate change.