title: Organic matter recycling in a beach environment influenced by sunscreen products and increased inorganic nutrient supply (Sturla, Ligurian Sea, NW Mediterranean).
abstract: The beaches are sites where the human influence may be strong and the beach ecosystems have often shown a high sensibility to environmental alterations. These zones may be affected by a large series of anthropogenic-derived pressures, such as unbalanced inorganic nutrient input, that may cause anomalous development of primary production, altering the structure of the trophic webs. Furthermore, the utilisation of cosmetic sunscreen products is reaching unexpected levels, thus assuming a potentially important as well as unknown role in the contamination of marine environments. The present study was planned to test the response of the beach ecosystem to increases in inorganic nutrients (nitrate and phosphate) and to the input of a widely used cosmetic sunscreen product. A short-term laboratory experiment was carried out on microsystems consisting of sediments and seawater from the swash zone of a Ligurian city beach (Sturla). The processes related to organic matter (OM) recycling and some microbial food web components (bacteria and micro-autotrophic organisms) were analysed. The multivariate statistical analysis of the results showed that the increase in inorganic nutrients and sunscreen caused only a transient alteration in the OM recycling processes in the seawater. The sedimentary processes, instead, were different in the different systems, although starting from the same condition. In the sediment, surprisingly, an increase in inorganic nutrients did not lead to an increase in the primary biomass nor to significantly higher bacterial abundance, while the sunscreen caused increased OM recycling, especially devoted to protein and lipid mobilisation, supporting a growing bacterial and autotrophic community by reducing the bottom-up pressure. Additional toxicity tests performed on protozoa highlighted that, while the inorganic nutrients seemed to show no effects, sunscreen decreased the protozoan viability, thus likely favouring microautotrophic and bacterial increases by reducing the top-down pressure.
authors.affiliation: Dip. Te. Ris.—University of Genoa, C.so Europa 26, 16132 Genoa, Italy. misic@dipteris.unige.it
authors.forename: Cristina
authors.initials: C
authors.lastname: Misic
authors.forename: Anabella
authors.initials: A
authors.lastname: Covazzi Harriague
authors.forename: Francesca
authors.initials: F
authors.lastname: Trielli
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D001493:Bathing Beaches; D055669:Ecological and Environmental Phenomena; D004784:Environmental Monitoring; D016812:Euplotes / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D008522:Mediterranean Sea; D015999:Multivariate Analysis; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D013473:Sunscreening Agents / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D009566:Nitrates; D010710:Phosphates; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical