Ms Giorgia Sanna1, Prof. Iacopo Bertocci1, Dr. Francesca Rossi2, Prof. Salvatrice Vizzini3, Dr. Serena Como4, Dr. Paolo Domenici5, Prof. Elena Maggi1
1Dept of Biology, CoNISMa, University of Pisa, Pisa, Italy, 2ECOSEAS Laboratory , CNRS, Nice, France, 3Dept of Earth and Sea Sciences, CoNISMa, University of Palermo, Palermo, Italy, 4IBF, CNR, Pisa, Italy, 5IAS, CNR, Oristano, Italy
Artificial light at night (ALAN) is recognized as a global source of anthropogenic disturbance. Within marine ecosystems, coastal areas are the most impacted by ALAN, but effects on organisms are still largely unknown. The sea urchin Paracentrotus lividus is an ecologically and economically important species in Mediterranean coastal systems; it is considered a nocturnal organism, with feeding and locomotion activities occurring mostly after sunset. We hypothesized that ALAN could negatively affect P. lividus’ nocturnal behaviour, by inducing an increasing escape response from artificial light sources at increasing light intensity. We also hypothesized that such a negative response could affect its nocturnal food search activity and therefore alter its diet composition.
We conducted a field experiment along an urban rocky shore, by taking advantage of areas characterized by different light intensities (from 0 to 18 lux), due to the presence of streetlamps and a restaurant. At each area, during new moon, clear sky summer nights we video-recorded the movement of sea urchins within transparent plastic arenas filled with sea water and placed on the rocky shore near the sea urchins’ collection point. We also collected individuals along with their main food resources for carbon and nitrogen isotopic analyses.
Results confirmed an escape response from artificial light and suggested that increasing ALAN intensity can alter isotropy readability and reduce habitat exploration in P. lividus. Moreover, a lower degree of diversification of the trophic niche was observed under lit conditions compared to natural darkness, despite a similar resource availability.
Presentation Slides – Elena Maggi
Biography:
Dr. Elena Maggi is a professor in ecology at the Dept of Biology of the University of Pisa. Since her PhD, she has gained experience in research on assessment of the consequences of loss of biodiversity, climate changes and anthropogenic impacts on macroalgal, invertebrate and biofilm assemblages. Her present interests are strongly focused on the impact of artificial light at night on coastal habitats. She is the promoter of the Global artificial Light Ocean netWork (GLOW), a collaborative network of scientists studying the potential effects of artificial light at night on coastal assemblages colonizing artificial structures worldwide.
