###### Abstract  
Numerous policies have been proposed by international and supranational institutions, such as the European Union, to surveil Earth from space and furnish indicators of environmental conditions across diverse scenarios. In tandem with these policies, different initiatives, particularly on both sides of the Atlantic, have emerged to provide valuable data for environmental management such as the concept of essential climate variables. However, a key question arises: do the available data align with the monitoring requirements outlined in these policies? In this paper, we concentrate on Earth Observation (EO) optical data applications for environmental monitoring, with a specific emphasis on ocean colour. In a rapidly changing climate, it becomes imperative to consider data requirements for upcoming space missions. We place particular significance on the application of these data when monitoring lakes and marine protected areas (MPAs). These two use cases, albeit very different in nature, underscore the necessity for higher-spatial-resolution imagery to effectively study these vital habitats. Limnological ecosystems, sensitive to ice melting and temperature fluctuations, serve as crucial indicators of a climate in change. Simultaneously, MPAs, although generally small in size, play a crucial role in safeguarding marine biodiversity and supporting sustainable marine resource management. They are increasingly acknowledged as a critical component of global efforts to conserve and manage marine ecosystems, as exemplified by Target 3 of the Kunming-Montreal Global Biodiversity Framework (GBF), which aims to effectively conserve 30% of terrestrial, inland water, coastal, and marine areas by 2030 through protected areas and other conservation measures. In this paper, we analysed different policies concerning EO data and their application to environmental-based monitoring. We also reviewed and analysed the existing relevant literature in order to find gaps that need to be bridged to effectively monitor these habitats in an ecosystem-based approach, making data more accessible, leading to the generation of water quality indicators derived from new high- and very high-resolution satellite monitoring focusing especially on Chlorophyll-a concentrations. Such data are pivotal for comprehending, at small and local scales, how these habitats are responding to climate change and various stressors. limnology; ocean colour; remote sensing; marine protected areas; small lakes; high-resolution satellites; governance 2024162597.12.2024162597.  
satellites, marking a significant milestone in planetary monitoring. Among the various components of the Earth system, the watery expanse stands out as the one benefiting most profoundly from space-derived data. Oceanography, traditionally a resource-intensive science, has seen a revolutionary shift, with satellites providing synoptic views and enabling the continuous monitoring of critical oceanic variables. Consequently, a comprehensive grasp of EO's role in shaping policy, as well as identifying existing gaps, is imperative for both current policies and future governance. While satellite data have long been acknowledged as an essential governance tool, we must now explore the new demands and opportunities to bridge the gap between policies and effective monitoring. Previous research has outlined that EO data are only present in 9% of lake shift studies, but its use is increasing over the last few years [2]. In this paper, we identify possible reasons on why EO data are not widely used to study marine protected areas and could be improved in limnological scenarios. Other environments such as rivers or lagoons are not part of this study since studying shifts over these areas is more challenging from a standpoint of satellite data alone.