Influence of tides on microgrowth bands in Cerastoderma edule from Norway

Abstract

At an intertidal site on the island of Tautra in Trondheimsfjord, Norway, cockles Cerastoderma edule L. were sampled from 121 cm (Stn A) and 66 cm (Stn B) below tidal datum. Shells were sectioned longitudinally, polished, etched and photographed under a scanning microscope to reveal microgrowth bands. Tidal heights were calibrated against a tide recorder in Trondheim harbour, thus providing immersion times and tidal heights for Stns A and B. The tidal and growth band data were subjected to time-series analysis. At Stn A, immersion time is maximal at neap tides while tidal height is maximal at spring tides, whereas at Stn B, maxima of both values occur at spring tides. Although both neap and spring tides have a cycle of 28 tidal periods, a cross-correlation analysis should show a phase shift of 14 periods at Stn A and no phase shift at Stn B.

Calcein and manganese experiments for marking the shell of the common cockle (Cerastoderma edule): tidal rhythm validation of increments formation

“…Variations in growth rate of molluscs are controlled by environmental factors and physiological constraints (Wilbur and Owen 1964;House and Farrow 1968;Schöne et al 2003). During the year, the growth rates of C. edule fluctuated, mainly due to the variations of sea temperature and the tidal patterns (Cole 1956;House and Farrow 1968;Lönne and Gray 1988). Our study in April however may not have been representative of the whole year.…”

“…Previous studies on C. edule growth addressed the increment formation periodicity (Bourget and Brock 1990), debating whether it follows a tidal (Richardson 1979(Richardson , 1980(Richardson , 1981Lönne and Gray 1988) or a circadian rhythm (Cole 1956;House and Farrow 1968). Different methods have been used (cold shock, time-series analysis, external ring census, etc.…”

“…In the same way, it could be carried out in several study sites and during a long period to determine growth variations in situ between seasons and habitats, and the influence of environmental parameters such as temperature, immersion time, current flow and trophic conditions (Richardson et al 1980;Lönne and Gray 1988). Shell growth of Crassostrea gigas was followed by manganese marking which had demonstrated that growth depends on seawater temperature changes (Lartaud et al 2010).…”

“…Nevertheless, only few studies have been carried out in the past. Current methods for age estimation of bivalves rely on quantification of growth ring on the shell surface or, at a smaller scale, on quantification of the internal micro-growth band, that may be related to periodical phenomena such as tidal or circadian rhythms (Richardson et al 1979;Lönne and Gray 1988;Kilada et al 2009). Cockle surface erosion and environmental disturbance may however obscure the identification of external growth rings (Cole 1956;Fahy et al 2005).…”

Use of calcein to estimate and validate age in juveniles of the winged pearl oysterPteria sterna

“…The existence of a sub-daily growth pattern has also been reported in the bivalves C. edule (House and Farrow 1968;Whyte 1975) and Chione cortezi (Goodwin et al 2001;Schöne et al 2002), although its relation with the physiology and periodicity of growth has not yet been established. In some cases, a subdaily growth rhythm has been associated with the presence of tides (Evans 1972(Evans , 1975Richardson et al 1979;Lonne and Gray 1988;Mahe et al 2010). Rodland et al (2006) suggested that these sub-daily growth patterns are controlled by internal rhythms or biological clocks, and that these mechanisms are in turn influenced by a complex interaction of physical (water temperature changes, daily light/dark cycles, tides, lunar cycle) and genetic cues (Beetjes and Williams 1985;Richardson 1988;Palmer 1995;Rodland et al 2006).…”