luca massi - Academia.edu (original) (raw)

Papers by luca massi

Proceedings of SPIE, Dec 17, 1999

The monitoring of organic matter, suspended or dissolved in the water column, is relevant for the... more The monitoring of organic matter, suspended or dissolved in the water column, is relevant for the study of the aquatic environment. Actually, the Dissolved Organic Matter (DOM) represents a major reservoir of reactive carbon in the global carbon cycle, thus influencing significantly the marine ecosystem. Due to the strong absorption in the near ultraviolet, DOM reduces considerably the extinction path

Oceanologica acta, Mar 1, 2003

The Orbetello lagoon consists of two coastal ponds, Laguna di Ponente and Laguna di Levante, char... more The Orbetello lagoon consists of two coastal ponds, Laguna di Ponente and Laguna di Levante, characterized by high nutrient concentrations, very poor exchanges with the sea and subjected to recurrent eutrophication crisis mainly in the past decades. To assess its current trophic status, from 1995 to 2001 the temporal evolution and spatial distribution of environmental factors, phytoplankton biomass and composition have been investigated. In this paper, the mean annual cycles of phytoplankton abundance, community structure and diversity are discussed. The seasonal cycles of micro-and nanophytoplankton densities are characterized by high frequency oscillations with fast increasing and decreasing blooms, but generally the lowest densities occur in winter, except for the peaks of December, and the highest ones during spring and summer. Despite the variability at short time scale of phytoplankton density, composition and diversity, a recurrent pattern was evidenced. Nanoplanktonic flagellates were the dominant fraction, mainly cryptophyceans during winter and early spring, while diatoms showed high summer blooms of nanoplanktonic centric genera and were very scarce during the other seasons, mainly with pennate genera. The phytoplankton community structure appeared to be more diversified from early summer to fall with the variable contribution of diatoms, dinoflagellates and other flagellates. Phytoplankton diversity, computed by means of the Shannon index, was relatively low (mean of 1.96 bit per cell) and two phases, common to the whole lagoon, have been evidenced: a first phase of lower diversity during winter and early spring, followed by an increasing trend that reached the highest diversity in late summer-fall. The pattern of nutrients' (DIN and DIP) availability and depletion leads to a seasonal change of the N/P ratio that seems to play a role as regards the phytoplankton community succession and then diversity, favoring or limiting the growth of the different groups.

Biological invasions are causing extensive damages to the ecosystems and the economy in many coun... more Biological invasions are causing extensive damages to the ecosystems and the economy in many countries around the world (1)(2) becoming a phenomenon of overriding concern. Myriophyllum aquaticum (Vell.) Verdc. (Fig.1) is an invasive macrophyte coming from South America, commonly used as an ornamental plant (3), and naturalized worldwide thanks to its phenotypic plasticity(3)(4). In Italy M. aquaticum has been reported in several regions (5). In Tuscany it was found in the wetlands of Lake Porta, between Lucca and Massa-Carrara (Fig. 2). This study aimed to provide a preliminary ecological survey of the invaded habitats around the Lake Porta and an assessment of M. aquaticum influence on these areas. The study involved 16 plots: 8 invaded by M. aquaticum and 8 non-invaded. In each of the 16 sampled plots, temperature, pH, salinity, dissolved oxygen and global and underwater irradiance were measured. Water samples were filtered and used for nutrient (NO 2

Ross Sea Ecology, 2000

Three years of investigation in the western Ross Sea reveal that despite the general abundance of... more Three years of investigation in the western Ross Sea reveal that despite the general abundance of phytoplankton biomass, the ratios between biomass and nutrient availability are low due to high nutrient concentrations. The N/P ratio is practically identical to that of Redfield; however, during blooms the ratio can be severely altered due to very low phosphate concentrations. Phytoplankton biomass during summer shows a bimodal cyclic pattern with two blooms in early and late summer. The spatial and temporal distribution of these blooms follows the latitudinal distribution of daily irradiance, which determines the advance of sea-ice melting from south to north forming an upper mixed layer rich in nutrients. This mixed layer is well illuminated and warmer than the deeper layer, thereby favouring the development of the early bloom. Afterwards, in the mixed water column, biomass decreases and reaches the summer minimum. A new stabilization of the water column is followed by a second bloom, less extensive than the first. In all 3 years, similar cycles have been recorded, giving corroborative evidence for the existence of a second bloom.

Sensors

Understanding and monitoring the ecological quality of coastal waters is crucial for preserving m... more Understanding and monitoring the ecological quality of coastal waters is crucial for preserving marine ecosystems. Eutrophication is one of the major problems affecting the ecological state of coastal marine waters. For this reason, the control of the trophic conditions of aquatic ecosystems is needed for the evaluation of their ecological quality. This study leverages space-based Sentinel-3 Ocean and Land Color Instrument imagery (OLCI) to assess the ecological quality of Mediterranean coastal waters using the Trophic Index (TRIX) key indicator. In particular, we explore the feasibility of coupling remote sensing and machine learning techniques to estimate the TRIX levels in the Ligurian, Tyrrhenian, and Ionian coastal regions of Italy. Our research reveals distinct geographical patterns in TRIX values across the study area, with some regions exhibiting eutrophic conditions near estuaries and others showing oligotrophic characteristics. We employ the Random Forest Regression algori...

The EGU General Assembly, 2018

The Lake Massaciuccoli is one of the largest and most important wetlands of Italian peninsula and... more The Lake Massaciuccoli is one of the largest and most important wetlands of Italian peninsula and is included in a protected area of regional and international relevance. In the present study, an update of the knowledge on aquatic and hygrophilous vegetation has been carried out, according to the phytosociological method. Some ecological analyses of the water trophism have been carried out, showing the high trophic level of the lake waters. The vegetation survey allowed to identify 31 plant communities belonging to 10 vegetation classes: Lemnetea minoris, Potametea pectinati, Bidentetea tripartitae, Isoëto-Nanojuncetea, Littorelletea uniflorae, Phragmito australis-Magnocaricetea elatae, Scheuchzerio palustris-Caricetea nigrae, Galio aparines-Urticetea dioicae, Molinio-Arrhenatheretea and Alnetea glutinosae. Aspects with Sphagnum sp. and other Bryophytes, present in small patches within the peculiar floating reed beds of the Thelypterido-Phragmitetum association, have been recorded a...

Port areas are generally affected by anthropogenic impacts, which favor pollution and spoil water... more Port areas are generally affected by anthropogenic impacts, which favor pollution and spoil water quality and aquatic ecosystems. In July 2015, a geochemical and biological transect was carried out in the Port of Viareggio (Tuscany, central Italy) from the main channel (Burlamacca), predominantly fed by the waters of the adjacent Massaciuccoli Lake, to the main docks and the open sea. Nine stations were studied for physical, chemical, bio-optical and biological parameters investigating, for each site, the vertical profile of the water column. The main aim was to provide a preliminary water quality assessment of the port area. The inorganic chemical composition highlighted the presence of mixing processes between seawater and low-salinity waters, causing a gradient of transitional waters and a vertical stratification of the water chemistry with increasing NaCl concentration in the deep waters and moving toward the sea while dissolved O2 was decreasing with depth and towards inland. R...

Advances in Oceanography and Limnology, 2011

Phytoplankton absorption is mainly determined by pigment composition and packaging into the cell,... more Phytoplankton absorption is mainly determined by pigment composition and packaging into the cell, in turn affected by pigment concentration and cell size and shape. The variations of the chlorophyll-specific absorption coefficients at two selected wavelengths (443 nm and 675 nm) were analysed for offshore areas of the Mediterranean Sea (Alboran, Algerian, Tyrrhenian, Ionian Basins and Sardinia Channel) investigated in autumn 2006, 2007 and 2008. The spatial distribution of Tchl a, accessory pigments, size structure and taxonomic composition of phytoplankton assemblages was diversified among the areas, characterized by higher contribution of photoprotective pigments in oligotrophic surface waters, while accessory chlorophylls increased in deeper layers and where microphytoplankton dominated. a Ã ph (443) values decreased from the oligotrophic waters to the more mesotrophic ones where microphytoplankton prevailed, while for a Ã ph (675) a small range of variation was observed. The differentiation of a Ã ph (443) was explained by the variations in the phytoplankton assemblage mean cell size, that consequently can be assumed as the main factor determining package effect. Comparison with previous parameterizations supported the existence of a Mediterranean differentiation for which the use of global models might determine inaccuracy for predicting phytoplankton absorption coefficients and thus refining ecological models.

Nell'ambito del progetto MOMAR l'attività di monitoraggio satellitare ha previsto la messa a punt... more Nell'ambito del progetto MOMAR l'attività di monitoraggio satellitare ha previsto la messa a punto di un sistema semioperativo di valutazione della qualità delle acque dei mari Ligure e Tirreno antistanti la Toscana, basato sulle concentrazioni della biomassa fitoplanctonica, stimata mediante la concentrazione della clorofilla (Chl), della sostanza organica disciolta cromoforica (CDOM) e del materiale particellato non fitoplanctonico (NAP). Sono state misurate in situ sia le proprietà ottiche del mare che le concentrazioni dei principali componenti attivi nel determinare il colore del mare e sono state valutate le loro relazioni con la biomassa fitoplanctonica con lo scopo di calibrare localmente algoritmi esistenti o proporne di nuovi per migliorare l'efficienza delle stime di Chl, CDOM e NAP. In particolare è stata valutata la stima della Chl da satellite tramite l'applicazione di diversi algoritmi ad immagini MODIS. Gli algoritmi considerati (OC3M, MedOC3, OC5, SAM_LT) hanno mostrato diversi livelli di accuratezza nelle acque costiere ed in quelle al largo. Questo studio ha consentito di definire alcune linee guida preliminari che saranno utili per il monitoraggio operativo dell'area marina in esame.

Journal of Applied Remote Sensing, 2012