RESUMEN
The European amphioxus (Branchiostoma lanceolatum) is a member of the chordate subphylum Cephalochordata, and, as such, a key model organism for providing insights into the origin and evolution of vertebrates. Despite its significance and global distribution, detailed characterizations of natural populations of cephalochordates are still very limited. This study investigates the abundance, habitat, and spawning behavior of amphioxus in the North Adriatic Sea. Across 32 sampled sites, adult amphioxus were consistently present, reaching densities exceeding 300 individuals m- 2. DNA barcoding confirmed the species as B. lanceolatum, and environmental analyses revealed an amphioxus preference for slightly gravelly sand with low silt content and a correlation between amphioxus density and the presence of specific macroinvertebrate taxa. Remarkably, the amphioxus population was breeding in early spring and possibly late fall, in contrast to the typical late spring/early summer spawning season described for other populations of European amphioxus. Amphioxus adults kept in captivity maintained the spawning seasonality of their place of origin, suggesting the possibility of extending the overall spawning season of European amphioxus in laboratory settings by exploiting populations from diverse geographic origins. This study thus expands our understanding of B. lanceolatum ecology and reproduction in the Mediterranean Sea, emphasizing the role of the North Adriatic Sea as a substantial reservoir.
RESUMEN
To quantify the possible impact of different wood protection techniques on the aquatic environment, we applied a tiered Integrated Testing Strategy (ITS) on leachates obtained from untreated (UTW) Norway spruce (Picea abies), specimens treated with a copper-ethanolamine-based preservative solution, complying with the Use Class 3 (UC3), and specimens thermally modified (TM). Different maturation times in water were tested to verify whether toxicant leaching is time-dependent. Tier I tests, addressing acute effects on Aliivibrio fischeri, Raphidocelis subcapitata, and Daphnia magna, evidenced that TM toxicity was comparable or even lower than in UTW. Conversely, UC3 significantly affected all species compared to UTW, also after 30 days of maturation in water, and was not considered an environmentally acceptable wood preservation solution. Tier II (effects on early-life stages of Lymnea auricularia) and III (chronic effects on D. magna and L. auricularia) performed on UTW and TM confirmed the latter as an environmentally acceptable treatment, with increasing maturation times resulting in decreased adverse effects. The ITS allowed for rapid and reliable identification of potentially harmful effects due to preservation treatments, addressed the choice for a less impacting solution, and can be effective for manufacturers in identifying more environmentally friendly solutions while developing their products.
Asunto(s)
Aliivibrio fischeri , Daphnia , Picea , Madera , Madera/química , Daphnia/efectos de los fármacos , Aliivibrio fischeri/efectos de los fármacos , Animales , Picea/química , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/análisis , Cobre/toxicidad , Cobre/química , Etanolamina/toxicidad , Etanolamina/química , Chlorophyta/efectos de los fármacos , Chlorophyta/crecimiento & desarrolloRESUMEN
During the second half of the twentieth century, coastal lagoons in densely populated regions experienced eutrophication due to excessive nutrient inputs. Detrimental effects, including hypoxia/anoxia and harmful algae blooms, have occurred in many Mediterranean lagoons, but their trophic evolution is poorly documented. The lack of adequate monitoring data can partly be offset by examining sedimentary records. In the Mar Piccolo, a lagoon comprising two basins near Taranto (Italy), eutrophication has followed population growth and pollution resulting from naval activities and massive industrialisation. Based on 210Pb-dated sediment cores, continuous in situ density profiles obtained with computed tomography, organic carbon (OC) and total nitrogen (TN) content and OC and TN isotopic signatures, this paper reconstructs the history of eutrophication, discusses the sources of organic matter and provides an estimate of the OC burial rate before and during the eutrophic period. OC burial increased in the period 1928-1935 and peaked in the decade 1960-1970. OC and TN content were still high in the surface sediments collected in 2013, despite partial diversion of sewage outfalls in the period 2000-2005. The divergent δ13C and δ15N signatures of the two basins during the eutrophic period suggest they were affected by different nutrient sources. The OC burial rate during the eutrophic phase (≈ 46 g m-2 y-1) was close to the world median value for lagoon sediments, and was about twice the burial rate recorded in the preceding oligotrophic phase.