Distribution, persistence and change in the macrobenthos of the lagoon of Lesina (Apulia, southern Adriatic Sea)

Abstract

The benthic community of the lagoon of Lesina was studied from July 2000 to June 2001. The distribution of the main macrophytobenthic species was recorded by visual census at 24 stations in July 2000. The macrofauna, from both hard and soft substrates, was analyzed at five stations with seasonal frequency; in addition, the main hydrologic parameters were recorded monthly. The lagoon was mainly characterized by brackish water, with salinity values decreasing from west to east (annual mean: 23.3 psu). It showed mild water temperatures throughout the year (annual mean: 19.8 °C) and moderately high values of dissolved oxygen (annual mean: 9.9 ppm). No dystrophic crises were observed during the period of study. In the eastern basin, Zostera noltii Hornemann, Lissara and Ruppia cirrhosa (Patagna) Grande were the most abundant species of macrophytobenthos. Their distributional pattern was coherent with literature data. Soft bottoms of the western basin were largely occupied by the benthopleustophytic alga Valonia aegagropila C. Agardh, which during the last decade had almost completely replaced Cladophora prolifera (Roth) Kützing and Gracilaria confervoides Greville, the latter of which was previously very abundant in the lagoon. Macrozoobenthos consisted of 53 species (1 sponge, 2 cnidarians, 11 molluscs, 14 annelids, 21 crustaceans, 1 insect, 1 bryozoan, 1 echinoderm, 1 tunicate), most of which are typical of brackish water. Highest abundances were found in the eastern area of the basin. Some marine species were recorded in the western area. In contrast with the dramatic changes observed in the floral assemblage, a large amount of species had already been recorded in the lagoon during the last 10 years, pointing out the persistence of the macrozoobenthic community. Nevertheless, the distribution of benthic macrofauna seemed to be greatly influenced by the presence of Valonia aegagropila, as shown in an ordination model, where station-points were segregated by the presence of the alga rather than by hydrologic parameters. The impact of biotic factors on the community, such as non-indigenous species invasions, was suggested as constraints inducing the temporal variations of benthos

Comparative study based on sediment characteristics and macrobenthic communities in two Italian lagoons

“…4). These results are consistent with those obtained by Marzano et al (2003) for Lesina lagoon and, similarly, many studies have shown a marked influence of organic enrichment on quali-quantitative composition of macrobenthos community (Gravina et al 1989;Labrune et al 2007;Mucha and Costa 1999;Sardà et al 1995;Sordino et al 1989).…”

“…On the basis of these observations (highlighted by PCA analysis also), a not marked but evident difference between the two lagoons was observed and supported by ANOSIM test that suggested a greater influence of external sources on sediment macronutrient distributions in Varano rather than in Lesina lagoon. In particular, these results indicate that the primary sources of organic matter in the sediments of Lesina lagoon (particularly in the western area) could be related to a high primary production (phanerogams) (Cozzolino 1995;Marzano et al 2003) rather than a loading of high amounts of urban waste waters, as highlighted by ordination diagrams (Fig. 3, no influence of external water input).…”

“…Due to their low water turnover and long residence time, many Mediterranean coastal lagoons are greatly affected by nutrient loads from their catchments (La Jeunesse and Elliott 2004). The high variability in chemical, physical and hydrologic parameters make them typically unstable environments (Millet and Guelorget 1994) and the concept of short-or long-term variations is relative for these ecosystems compared to marine environments (Marzano et al 2003). Urban development and human activity on coastal lagoons have increased considerably in recent years, and the impact on these productive and economically important environments has become a major concern.…”

Benthic foraminiferal assemblages and trace element contents from the lagoons of Orbetello and Lesina

“…The average water depth is 0.8 m, with the maximum of less than 2 m (Ricci Lucchi et al 2006). Bottom sediments mainly consist of mud and sand (Nonnis Marzano et al 2003). Like the lagoon of Orbetello, the lagoon of Lesina has experienced a progressive eutrophication followed by occasional dystrophic crises due to the abnormal proliferation of the green algae Valonia utricularis (Manini et al 2003).…”

Migratory crustaceans as biomonitors of metal pollution in their nursery areas. The Lesina lagoon (SE Italy) as a case study

“…Zoostera noltii and Ruppia cirrhosa are the most abundant macrophytobentos species in the western and central-eastern basin respectively. Macrozoobenthos mainly consists of mussels, anellida and crustaceans (Nonnis-Marzano et al 2003).…”