Nutrient enrichment and phytoplankton response in an Adriatic karstic estuary

Evidencing the natural and anthropogenic processes controlling trace metals dynamic in a highly stratified estuary: The Krka River estuary (Adriatic, Croatia)

“…The most interesting feature of this estuary is a boundary FSI layer in which an enrichment of the organic matter and trace elements was found as a results of the specific physical and chemical properties (Bilinski et al, 2000;Mantoura, 1987;Zutic and Legovic, 1987). First studies of trace metals , organic matter and SPM (Cauwet, 1991) and biological activities (Denant et al, 1991;Grzetic et al, 1991;Legovic et al, 1991a;Legovic et al, 1991b;Legovic et al, 1991c;Legovic et al, 1994) revealing the low pollution within the estuary were partially confirmed by more recent studies (Bilinski et al, 1992;Bilinski et al, 2000;Cetinic et al, 2006;Louis et al, 2009;Omanović et al, 2006;Supraha et al, 2014). An anthropogenic influence noticed in the estuary was mainly related to the increased nautical tourism in (Louis et al, 2009;Omanović et al, 2006).…”

Net Submarine Groundwater‐Derived Dissolved Inorganic Nutrients and Carbon Input to the Oligotrophic Stratified Karstic Estuary of the Krka River (Adriatic Sea, Croatia)

“…Nutrients in the KRE were discussed extensively in relation to the freshwater inflow of the Krka River and anthropogenic sources from the city of Šibenik (Gržetić et al, ; Legović et al, ; Svensen et al, ). Here, we have determined that the Krka River contributed 22.4 × 10 3 mol DIN per day, 1.3 × 10 3 mol DIP per day, and 150 × 10 3 mol DSi per day to the analyzed section of the estuary during the sampling period (Figure ).…”

“…Therefore, the Krka River significantly controls the depth of the sharp salinity gradient (halocline). A relatively thick (10–50 cm) halocline layer in the KRE is positioned between the depths of 2 and 5 m (Gržetić et al, , and references therein). There is an organic film developed at the halocline (Žutić & Legović, ), enriched by dead freshwater phytoplankton and zooplankton fecal pellets (Ahel et al, ; Denant et al, ).…”

“…Although numerous studies have described the ecosystem of the KRE (e.g., Cetinić et al, 2006;Viličić et al, 1989), there are no reports on the importance of SGD as nutrient and DIC source for the Krka River, its estuary, and the regions of the coastal Adriatic Sea under their direct influence. Gržetić et al (1991) mentioned groundwater springs in the upper KRE without evaluating their influence, while Cauwet (1991) reported on the DIC in the Krka River, but not in the SGD entering the KRE. Many studies dealt with SGD and its derived materials in the Mediterranean Sea regions, but only a few of them are related to DIC (Garcia-Solsona, Garcia-Orellana, Masqué, Garces, et al, 2010;Rodellas et al, 2015).…”

N:Si:P atomic ratio in the Santa Cruz Channel, Itamaracá-PE (Northeast Brazil): a nyctemeral variation

“…The concentration of nutrients varies distinctively in time and space, and even between tide cycles (Flores Montes, 1997). For Grzetic et al, (1991), the variation in the estuary of the river Krka (Adriatic) can be explained by the combined influences of different processes, such as biological assimilation of the nutrients/ cycle of regeneration, sweet water discharge, anthropogenic contribution, horizontal and vertical advection, and others; some of these processes predominate over others, in different parts of the water column and/or different zones of the estuary. An understanding of the chemical factors that regulate the biomass and the production of the whole aquatic ecosystem, requires a detailed evaluation of the factors that control the biodisponibility of the essential nutrients.…”