###### Abstract
Whilst some studies have delved into the use of these satellites for Chlorophyll-a estimations, their low spectral resolutions suggested that these satellites can still be used but are sub-optimal to effectively assess these ecosystems since Chlorophyll-a detection is only possible under very specific conditions ([PERSON] et al., 2017; [PERSON] et al., 2018; [PERSON] et al., 2018). Marine protected areas (MPAs) exhibit similarities with lakes in terms of ecological significance, social benefits, and economic value. They also play a role in biodiversity conservation, fisheries management, and carbon capture. MPAs, especially those preserving specific ecosystems like seagrass beds and mangroves, have the potential to store significant amounts of carbon, contributing to climate change mitigation. It has been assumed that ocean habitats such as seagrasses and mangroves (and associated food webs) can sequester carbon dioxide from the atmosphere at rates up to four times higher than terrestrial forests can ([PERSON] et al., 2018). However, estimations of this \"blue carbon\" sequestration rate can be two orders of magnitudes higher when considered on a \"per area\" basis (Mangroves and other coastal habitats are some of the most carbon-rich ecosystems (Mangroves and others, 2018) although discussions about the precise contributions and menaces of blue carbon sequestrations are still elusive and new advances are dependable on EO data ([PERSON] et al., 2018). Because of the natural habitats they encompass, MPAs are very sensitive to climate change and other environmental impacts. The definition of MPA objectives should also be enlarged as in many cases they are restricted to non-take areas and should comply to a more effective ecosystem-based management approach ([PERSON] et al., 2018). High-resolution satellites, already used to survey fishing activities in sensitive areas ([PERSON] et al., 2018), are critical to address other aspects of MPAs ensuring ocean health and better marine conservation. The role of higher-resolution satellites in addressing diverse aspects of MPAs and lakes, and their sensitivity to climate change and environmental threats cannot be over-stated. From such methods, we can derive indicators to assess the status and help to meet important environmental targets, such as the Kunming-Montreal Global Biodiversity Framework. Nevertheless, the challenge lies in developing methods for consistent and synoptic monitoring, particularly in areas that are often isolated or too small for satellite observation, limited not by technology but by policies and restrictions on the collection, use and exploitation of VHR data. This article will analyse the EO-based environmental surveillance assets at the European level. Since Copernicus is currently seen as the largest EO programme in the world in terms of budget, scope, and applications, we want to analyse what are the current scientific applications of EO data in small water bodies such as lakes and MPAs. Then, we move to the prospectives on the feasibility of high- and very high-resolution satellites for lake and ocean colour by revising many studies that have considered and tested the feasibility of data outside of the Copernicus programme to monitor water quality. Finally, we discuss the application to governance of this ecosystem-based monitoring and conclude on the needs for future data.