Long-term coastal marine waters quality monitoring Sozopol, Bulgaria carried out by the Laboratory for Marine Ecolgy, IBER-BAS, 01.2013-11.2021 The dataset consists of weekly measurements of paramters of surface marine waters sampled at a location in Sozopol Bay, Bulgarian Black Sea coast. Measured paramters include water temperature and salinity, concentrations of ammonia, nitrates, nitrites, total nitrogen, organic nitrogen, phosphates, sestone and chlorophyll-a. Dataset is already available in the Emodnet Chemistry portal under the following ID: https://cdi.seadatanet.org/search/welcome.php?query=2229&query_code={87CC15A6-67F6-4B48-BBA4-A09B5D3AF4C6}