Challenges and opportunities towards meeting the United Nations' Sustainable Development Goals from coral and seaweed ecosystems in an era of climate change

Global climate change scenarios due to anthropogenic responses jeopardize ecosystem sustainability and hinder progress toward achieving the United nations (UN-SDGs). Achieving "natural carbon solutions" from terrestrial ecosystems is challenging due to decreasing arable land and increasing marginal land. Marine ecosystems representing a wider "natural carbon solutions" have also been severely impacted by climate change. Among marine ecosystems, coral reefs and seaweed communities are the key ecosystem engineers that support a wide range of marine life, facilitate nutrient cycling, and provide essential ecosystem services with a pivotal role in sustaining coastal economies and livelihoods. Notably, these communities compete for space within the reef ecosystem and suffer from loss of diversity and richness due to climate change. Therefore, assessing the climate change resilience of both the corals and seaweeds is essential to evaluate and design long-term adaptation strategies, ecological innovations, and science-informed policies to conserve, restore, and sustainably manage economic services. This review article aims to highlight (1) the physiological response and resilience of corals and seaweeds to environmental changes, (2) the impact of climate change on their ecosystems and economic services, (3) their potential contributions towards the United Nations' sustainable goals, (4) progressive efforts applied for their restoration, and (5) the potential complementary value of large-scale seaweed aquaculture as a carbon sink.