Cymodocea nodosa meadows as a summer refuge for Gongolaria barbata recruits in the Venice Lagoon
1
Department of Biology, University of Naples Federico II, Cupa Nuova Cintia, 21, Napoli, NA - 80126, Italy
2
Department of Biology, University of Padova, Viale Giuseppe Colombo, 3, Padova, VE - 35131, Italy
3
Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn,, V. Francesco Caracciolo, Napoli, NA - 80122, Italy
4
NBFC, National Biodiversity Future Centre, Piazza Marina, 61, Palermo, PA - 90133, Italy
Due to multiple anthropogenic and climatic stressors, macroalgal forests are undergoing a rapid decline. These valuable ecosystems in the Mediterranean Sea support biodiversity and provide important ecosystem services. This highlights the importance of studies in this field regarding the adaptability of macroalgae to various environmental conditions. This research focuses on the macroalga, Gongolaria barbata, an element of great ecological value, especially prevalent in the lagoon areas of the Adriatic Sea.
In winter, macroalgal forests of G. barbata expand. In spring, they coexist with forests produced by the seagrass Cymodocea nodosa and are then completely replaced by the latter in the summer, forming a cycle of seasonal alternation.
It has been noted that several of Cymodocea's physiological characteristics allow it to adapt even to situations not entirely optimal for its physiology within the lagoon environment. Within this general framework, the present study aims to highlight the importance of possible cooperation, both direct and indirect, between the two species, which will promote their growth in the lagoon. It is hypothesized that during the summer period, when G. barbata regresses, its new recruits can find shelter from strong solar radiation, thereby increasing their growth potential when protected by Cymodocealeaves. Simultaneously, it is speculated that G. barbata itself can provide nutrients to the substrate, which facilitates the expansion of Cymodocea.
To support these hypotheses, during the spring period characterized by the reproductive phase of G. barbata, supports were set up within the macroalgal forests of the lagoon to allow new recruits to attach. These samples will then be moved from three initial sites to sites characterized by the presence and absence of Cymodocea. During the summer, the growth and physiological performances of G. barbata recruits will be evaluated in both the presence and absence of the seagrass. Various parameters will be evaluated from these samples, including growth, phenology, photosynthetic production, and respiration.
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