Environmental influence on calcification of the bivalve Chamelea gallina along a latitudinal gradient in the Adriatic Sea

Abstract

Environmental factors are encoded in shells of marine bivalves in the form of geochemical properties, shell microstructure and shell growth rate. Few studies have investigated how shell growth is affected by habitat conditions in natural populations of the commercial clam Chamelea gallina . Here, skeletal parameters (micro-density and apparent porosity) and growth parameters (bulk density, linear extension and net calcification rates) were investigated in relation to shell sizes and environmental parameters along a latitudinal gradient in the Adriatic Sea (400 km). Net calcification rates increased with increasing solar radiation, sea surface temperature and salinity and decreasing Chlorophyll concentration in immature and mature shells. In immature shells, which are generally more porous than mature shells, enhanced calcification was due to an increase in bulk density, while in mature shells was due to an increase in linear extension rates. The presence of the Po river in the Northern Adriatic Sea was likely the main driver of the fluctuations observed in environmental parameters, especially salinity and Chlorophyll concentration, and seemed to negatively affect the growth of C . gallina .

Age and Growth of Striped Venus Clam Chamelea gallina (Linnaeus, 1758) in the Mid-Western Adriatic Sea: A Comparison of Three Laboratory Techniques

“…According to our findings, the two shell sectioning techniques were equally reliable, whereas the shell surface growth ring approach underestimated age. Indeed, the approach has yielded contrasting results in various bivalve species, either underestimating (Gaspar et al, 2004;Hernández-Otero et al, 2014) or overestimating age (Gaspar et al, 1995; Peharda et al, 2002), despite the occasional success (Mancuso et al, 2019). In our study, underestimation was due to the large amount of shells presenting a smooth surface with no clefts, independently from the size, which led to a mismatch with the length-at-age data derived from the internal readings.…”

“…Several factors, including spawning, food availability, type of substratum, depth, light, temperature, salinity and population density may affect shell growth rate (Gaspar et al, 2004;Dalgiç et al, 2010). Growth is the result of linear extension along the umbonal-ventral axis per unit of time, and slows down with increasing age or size (Lorrain et al, 2004), as also confirmed by isotope analysis (Keller et al, 2002;Mancuso et al, 2019).…”

“…In areas characterized by such density the strong competition for food limits growth and in extreme cases leads to mass mortality events (Liu et al, 2006). Fluctuations in salinity and rising chlorophyll concentration negatively affect C. gallina growth in the western Adriatic Sea (Mancuso et al, 2019), as well as temperatures below 10 • C and above 27 • C slow or inhibit shell linear extension rates (Ramón and Richardson, 1992;Moschino and Marin, 2006;Romanelli et al, 2009). Even a study carried out at the coastal station of the LTER (Long Term Ecosystem Research) Senigallia-Susak transect, ca.…”

“…Studies of bivalve population dynamics require a thorough knowledge of their growth rate and age and are essential to develop effective fishery management measures (Mancuso et al, 2019). Age and growth have extensively been investigated for bivalve mollusks in different geographical areas with a variety of methods, including mark and recapture (Jones et al, 1978;Ropes et al, 1984;Adjei-Boateng and Wilson, 2013), size-frequency distribution analysis (Froglia, 2000;Herrmann et al, 2009), shell surface growth rings (Fiori and Morsán, 2004;Adjei-Boateng and Wilson, 2013), thin sections (Christian et al, 2000;Dalgiç et al, 2010), acetate peel replicas (Ramón and Richardson, 1992;Gibson et al, 2001;Gaspar et al, 2004;Masu et al, 2008) and isotope analysis (Keller et al, 2002;Mancuso et al, 2019).…”

Using the Stable Isotopic Composition of Heliconoides inflatus Pteropod Shells to Determine Calcification Depth in the Cariaco Basin

“…There are significant differences in δ 13 C variability between juvenile (<1 mm) and (>1 mm) adult pteropod shells (F = 3.60, p = 0.0087) which may indicate the presence of a metabolic vital effect ( Figure 4B). The isotopic composition of scallop specimens displaying high growth rates has been found to deviate more from isotopic equilibrium than specimens with slower growth rates (Owen et al, 2002), and several studies have found that growth rates decrease and become less variable with age (Schöne et al, 2005;Butler et al, 2010;Mancuso et al, 2019). Assuming similar relationships occur in pteropods, the increased variability in δ 13 C of juvenile pteropods relative to adults could be attributed to higher growth rates in smaller specimens.…”