Search

We assessed ecological quality status (EQS) of coastal waters following claims of increasing sea turtle fibro-papillomatosis (FP) infections in Kenya, a disease hypothesized to be associated with 'poor' ecological health. We established widespread phosphate (P) and silicate (Si) limitation, dissolved ammonium contamination and an increase in potential harmful algal blooming species. Variations in the EQS was established in the sites depending on the indicators used and seasons. Generally, more sites located near hotels, tidal creeks, and estuarine areas showed 'poor', and 'bad' EQS during rainy period compared to dry season. Additionally, 90.1 % of the sites in 'poor' and 'bad' EQS based on dissolved inorganic nitrogen. Low dissolved oxygen, elevated temperature, salinity and ammonium, 'poor' EQS based on DIN, and potential bio-toxin-producing phytoplankton species characterized the FP prevalent areas, specifically during the dry season suggesting environmental stress pointing to the hypothesized connection between ecological and sea turtle health. • Ammonium-dominated dissolved inorganic nitrogen-DIN based 'poor' ecological quality status in sea turtle foraging sites. • Phosphorus and silicate limitations with DIN surplus increasing during the rainy season. • Ammonium, silicate and harmful diatoms are elevated in estuaries. • High ammonium and phosphate co-occur with harmful dinoflagellates in the tidal creeks. • Co-occurrence of 'poor' and 'bad' ecological quality status with sea turtle tumors prevalence areas. [ABSTRACT FROM AUTHOR]

Nutrients and Phytoplankton composition are important indicators of coastal water quality used for fisheries, tourism, and recreational purposes, which are the cornerstone of the blue economy. This is a comprehensive review and synthesis of the outcome of previous empirical studies conducted on anthropogenic nutrients (nitrogen and phosphorus) and phytoplankton productivity and community composition with a particular focus on harmful algal blooms (HABs) in Kenya's coastal and marine waters. Our results indicate that localized nutrient pollution occurs in estuaries and creeks adjacent to urban areas. Nitrogen speciation was characterized by high ammonium relative to nitrate concentrations with evidence of nitrogen limitation (N: P < 16). Based on all studies' average chlorophyll a concentration, seawater in coral and seagrass ecosystems was classified as mesotrophic, mangroves and nearshore as higher mesotrophic, and estuarine and creeks as eutrophic. Additionally, 44 species of potential toxin-producing HAB-forming species belonging to 22 genera were established in low abundances (3±2 - 210±11 cells/l) below the standards of HAB's warning thresholds. Their drivers, spatial and temporal trends are, however, unclear. This review revealed the existence of localized nutrient pollution and a low abundance of toxin-producing HABs species in Kenya's coastal waters. The existing data is, however, very fragmented and inadequate to guide coastal managers in addressing the problem of anthropogenic nutrient pollution and HABs in the area. We, therefore, recommend the inclusion of anthropogenic nutrients and toxic HABs in routine water quality monitoring in the area, especially in potential fisheries, aquaculture, tourism, and recreational sites. • Localized nutrient (nitrogen and phosphorus) pollution occurs in creeks bordering urban areas and estuaries. • Occurrence of N limitation for primary production in most areas with high ammonium relative to nitrate concentrations. • Corals and seagrass are mesotrophic, mangroves are higher mesotrophic, estuarine and creeks are eutrophic based on Chl a. • Existence of 44 species of potential toxin-producing HABs in low abundances below the standards of HAB's warning systems. [ABSTRACT FROM AUTHOR]