WileyMorata Higón, T.; Falco Giaccaglia, SL.; Gadea, I.; Sospedra Ciscar, J.; Rodilla Alamá, M. (2013). Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) This study examined the effects of organic enrichment on water column, sediments and macrofauna caused by a fish farm in the Mediterranean Sea. Samples were collected on four sampling campaigns over a one-year cycle. Significant differences were found in the water column in dissolved oxygen, dissolved inorganic nitrogen, phosphate and total phosphorus concentrations between the fish farm and the control. The increase in the dissolved inorganic nitrogen and phosphate concentrations at the fish farm modified the stoichiometric ratios between nutrients, with silicate acting as limiting nutrient at the fish farm 11% more than at the control. Nevertheless, chlorophyll a concentration in the water column was higher at the control station, probably due to the fouling of the underwater fish farm structures. Significant differences were found in sediment concentrations of organic matter, total phosphorus and redox potential between the fish farm and the control. The Canonical Correlation Analysis indicated that organic matter, total phosphorus, redox potential and % of gravels accounted for 68.9% of the total variance in the species data. Changes were observed in macrofauna, with a decrease in number of species and up to a nine-fold increase in abundance with respect to the control.

Morata, T.; Sospedra, J.; Falco Giaccaglia, SL.; Rodilla Alama, M. (2012). Exchange of nutrients and oxygen across the sediment-water interface below a Sparus aurata marine fish farm in the north-western Mediterranean Sea. Journal of Soils and Sediments. 12(10):1623-1632. doi:10.1007/s11368-012-0581-2. It is the first of its kind to be based on benthic flux data gathered in situ below fish farms for this particular area. Materials and methods Samples were collected on four samplingcampaigns over a 1-year cycle under a Sparus aurata fish farm facility where benthic fluxes were measured in situ using light and dark benthic chambers.Bottom water and sediment samples were also collected. Data were compared to those for a nearby control station.Results and discussion Significant differences were found (ANOVA,

Elsevier Sospedra, J.; Falco, S.; Morata T.; Gadea, I.; Rodilla, M. (2015). Benthic fluxes of oxygen and nutrients in sublittoral fine sands in a north-western Mediterranean coastal area. Continental Shelf Research. 97:32-42. doi:10.1016Research. 97:32-42. doi:10. /j.csr.2015 AbstractTraditionally, benthic metabolism in sublittoral permeable sands have not been widely studied, although these sands can have a direct and transcendental impact in coastal ecosystems. This study aims to determine oxygen and nutrient fluxes at the sediment-water interface and the study of possible interactions among environmental variables and the benthic metabolism in well-sorted fine sands. Eight sampling campaigns were carried out over the annual cycle in the eastern coast of Spain (NW Mediterranean) at 9 meters depth station with permeable bottoms. Water column and sediment samples were collected in order to determine physico-chemical and biological variables.Moreover, in situ incubations were performed to estimate the exchange of dissolved solutes in the sediment-water interface using dark and light benthic chambers. Biochemical compounds at the sediment surface ranged between 160-744 µg g -1 for proteins, 296-702 µg g -1 for carbohydrates, and between 327-1224 µg C g -1 for biopolymeric carbon. Chloroplastic pigment equivalents in sediments were mainly composed by chlorophyll a (1.81-2.89 µg g -1 ).These sedimentary organic descriptors indicated oligotrophic conditions according to the biochemical approach used. In this sense, the most abundant species in the macrobenthic community were sensitive to organic owing to the highest incident irradiance levels (r=0.98, p<0.01) that stimulate microphytobenthic primary production. Microphytobenthos played an important role on benthic metabolism and was the main primary producer in this coastal ecosystem. However, an average annual uptake of 31 mmol m -2 d -1 of oxygen and a release of DIN and Si(OH) 4 (329 and 68 mmol m -2 d -1 respectively) were estimated in these bottoms, which means heterotrophic conditions.

An environmental recovery study was carried out after the cessation of a gilt-head seabream farm off the Mediterranean coast of Spain. Physicochemical variables of sediments, in situ benthic fluxes of oxygen and nutrients, and benthic macrofauna were measured in the farming area and at a control station. Five sampling campaigns were done, one before the closure and the others at 1, 3, 9, and 24 mo after cessation. Benthic flux of ammonium was the first variable to recover, followed by benthic fluxes of phosphate and dissolved oxygen and percentage organic matter in the sediments, which 3 mo after the cessation of farming already showed levels similar to those in the control station. Nine months after cessation, the other abiotic variables of the sediments disturbed by the activity had recovered, such as percentage coarse fraction, total phosphorus concentrations, and redox potential measurements. The recovery of the macrofauna was slower than the abiotic variables. Three months after cessation, Capitella capitata abundance had reduced drastically in the farming area, but similar specific richness levels were not observed between the two sampled zones until 2 yr after farming cessation.

Influence of organic enrichment and Spisula subtruncata (da Costa, 1778) on oxygen and nutrient fluxes in fine sand sediments