Browsing by Author "Mazzuca, S."
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- Acoustic monitoring of O2 production of a seagrass meadowPublication . Felisberto, P.; Jesus, S. M.; Zabel, F.; Santos, Rui; Silva, João; Gobert, S.; Beer, S.; Bjork, M.; Mazzuca, S.; Procaccini, G.; Runcie, J. W.; Champenois, W.; Borges, A. V.Acoustic data were acquired in October 2011 over a Posidonia oceanica meadow in the Bay of la Revellata, Calvi, Corsica. The purpose was to develop an acoustic system for monitoring the oxygen (O2) production of an entire seagrass meadow. In a shallow water area (<38m), densely covered by P. oceanica, a sound source transmitted signals in 3 different bands (400-800Hz, 1.5-3.5kHz and 6.5-8.5kHz) toward three self-recording hydrophones at a distance of 100m, over the period of one week. The data show a high correlation between the diel cycle of the acoustic signals' energy received by the hydrophones and the temporal changes in water column O2 concentration as measured by optodes. The results thus show that a simple acoustic acquisition system can be used to monitor the O2-based productivity of a seagrass meadow at the ecosystem level with high temporal resolution. The finding of a significant production of O2 as bubbles in seagrass ecosystems suggests that net primary production is underestimated by methods that rely on the mass balance of dissolved O2 measurements. © 2015 Elsevier B.V.
- Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism and ecosystem carbon fluxesPublication . Mazzuca, S.; Bjork, M.; Beer, S.; Felisberto, P.; Gobert, S.; Procaccini, G.; Runcie, J. W.; Silva, João; Borges, A. V.; Brunet, C.; Buapet, P.; Champenois, W.; Costa, M. M.; D'Esposito, D.; Gullström, M.; Lejeune, P.; Lepoint, G.; Olivé, Irene; Rasmusson, L. M.; Richir, J.; Ruocco, M.; Serra, I. A.; Spadafora, A.; Santos, RuiA complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research.This enables the predictionof change and possibly the mitigation of the consequences ofanthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES0609 “Seagrasses productivity. From genes to ecosystem management,” is the calibration and synthesis of various methods and the development of innovative techniques and protocolsfor studying seagrass ecosystems. During 10 days, 20 researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, and underwater acoustics) gathered at The Station de Recherches Sous-marines et Océanographiques (STARESO, Corsica) to study together the nearby Posidonia oceanica meadow. STARESO is located in an oligotrophic area classified as “pristine site” where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, which grows in front of the research station, colonizes the sea bottom from the surface to 37m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.
- Seagrass photo-physiological responses in natural high-CO2 environmentPublication . Costa, Monya; Olivé, Irene; Barrote, Isabel; Procaccini, G.; Mazzuca, S.; Vizzini, Salvatrice; Santos, RuiThe atmospheric concentration of CO2 has been steeply increasing over the last 200 years, with an associated increase of total dissolved inorganic carbon (Ci) and a decrease of the oceans’ pH. Seagrasses are among the most productive marine ecosystems, but yet little is known on the effects of high-CO2/low pH on their photosynthetic physiology and the ecological consequences. Marine CO2 seepage areas have been used as natural laboratories to investigate the performance of marine organisms under long-term exposure to high-CO2 levels that mimic the future ocean. In this work we conducted a series of experiments comparing the photophysiology of the seagrasses Posidonia oceanica and Cymodocea nodosa, growing in the vicinity of submarine CO2 vents around the islands of Vulcano and Panarea (Aeolian Archipelago, Southern Tyrrhenian Sea, Italy). Plants growing close to CO2-seepage sites were compared with plants from control sites. Automated chlorophyll fluorometers were deployed for 24-hour periods to examine the changes in photosynthetic efficiency and energy quenching mechanisms. Samples were collected at predawn and noon and analyzed for pigment composition, antioxidant capacity, and soluble carbohydrates. Differences in gene and protein expression were evaluated as a function of Ci levels. Stable carbon isotopes (δ13C) were also analysed to investigate the contribution of volcanic CO2 to seagrass productivity. Both P. oceanica and C. nodosa plants growing in CO2-seepage sites showed lower allocation of PSII-absorbed energy to photochemistry (φII), while presenting higher proportions of energy dissipation by non-photochemical pathways (down-regulation, φNPQ and other energy losses, φNO). As well, diel photosynthesis-irradiance curves (ETRI), built with data acquired over the 24-hour deployments, showed lower photosynthetic rates in plants from CO2 seepage sites. This unexpected pattern of photosynthetic activity will be discussed in light of the complementary data.