Editorial: World’s oceans: opportunities and challenges looking under the sea

The oceans are home to a vast biodiversity below their surface, offering innumerable opportunities that remain mostly untapped. In recent years, marine organisms have drawn increasing interest as a renewable and sustainable source of pharmacological, food and cosmetic bioactive compounds (Ebrahimi et al., 2023). In addition, the great biodiversity of organisms, from invertebrates to algae, and the interactions among them, are being studied in search of sources of renewable energy (Borowitzka and Moheimani, 2013), sewage treatment mechanisms (Sutherland and Ralph, 2019), aquaculture techniques (Ma and Qin, 2023), among other aspects.However, the sustainable use of these resources also draws enormous challenges that must be overcome. The numerous pollutants found in marine ecosystems (such as microplastics and nanoparticles, heavy metals and nutrients), high population densities in many coastal areas and poor public policies addressing these issues, all pose a threat to the unique, resource-rich coastal and marine biodiversity (Gobas and Morrison, 2000;Cloern, 2001;Andrady, 2011;Holmes et al., 2012). This Research Topic focuses on the emerging opportunities and challenges related to the utilization of marine resources, with a view to coordinating efforts towards a sustainable development. The articles published in this Topic, reveal the interconnected roles of marine organisms, including diatoms, macroalgae and polychaetes, and their potential for nutrient recycling and sustainable aquaculture practices, underscoring the complex dynamics of marine ecosystems in the face of anthropogenic pressures and climate change (Figure 1).The intricate dynamics of marine ecosystems necessitate a multifaceted 40 of their constituent particularly those serving as primary 41 producers. Among these, diatoms are the main components of marine phytoplankton.These unicellular algae one of the main primary producers in the marine ecosystem,