Growth trends in three bivalve species indicate climate forcing on the benthic ecosystem in the southeastern North Sea

Abstract

Internal growth lines in shells of 3 suspension-feeding bivalves (Arctica islandica, Mya truncata and Chamelea striatula) from the SE North Sea were analysed in search of common interannual variations of their growth rate. The high similarity (69 to 80%) between the growth records in the 3 species suggests that a large-scale (climatic) factor is responsible for an important part of the variation in annual shell growth. The common trend extracted from the individual growth records was correlated with monthly data on phytocolour, NAO index, temperature and wind. The strength and sign of the effect of the last 3 factors varied seasonally. Effects of wind strength and direction were analysed in detail, as in situ measurements showed that wind speeds >10 m s -1 (Beaufort 6) cause resuspension of fine sediment at the site where the bivalves were collected. Resuspended sediment causes a drop in the quality of food for suspension feeders. During the bivalve growing season, northwesterly to easterly winds tended to depress growth, whereas winds with a westerly component mainly had a positive effect. Strong winds from a WNW direction in May, however, had a negative effect and could explain the highest proportion of variance in the common growth trend; WNW winds have a long fetch at the study area and generate (high) long waves, facilitating resuspension of fine sediment at relatively low wind speeds.

Detecting population heterogeneity in effects of North Atlantic Oscillations on seabird body condition: get into the rhythm

“…These results suggest that weather conditions principally affect bird condition the following year through effects on the food chain. Winter temperature or storminess could affect the productivity of molluscs (the main food resources of eiders during winter, Bustnes 1998, Merkel et al 2007) through changes in growth (Menge et al 2008), reproduction, survival (Thieltges et al 2004) or shell thickness, and thus digestibility (Bustnes 1998, Witbaard et al 2005). More specifically, eiders at Grindøya are very selective in terms of prey size and feed primarily on small mussels (<20 mm, Bustnes and Erikstad 1990, Bustnes 1998), which might correspond to 1‐year old mussels (Thompson 1984, Mills and Côté 2003).…”

The consequences of changes in abundance of Callianassa subterranea and Amphiura filiformis on sediment erosion at the Frisian Front (south-eastern North Sea)

“…These mounds increase the boundary roughness and shear stress making the sediment more susceptible to erosion (Rowden et al, 1998b). Thirdly, evidence from a variety of habitats, including the North Sea and the Frisian Front, shows that many organisms collecting food at sediment-water interface, such as bivalves but also tubicolous polychaetes and echinoids, are negatively affected by suspended sediment (Nicholls et al, 2002;Witbaard et al, 2001Witbaard et al, , 2005.…”

Environmental influence on the bottom and near-bottom megafauna communities of the Dogger Bank: a long-term survey

“…The growth rings of its shell are a good index for climatic events, impressively demonstrated by Schöne et al (2003Schöne et al ( , 2005. Additionally, the shell of A. islandica together with the shells of Mya truncata and Chamelea striatula can be used to show sediment re-suspension strength due to storms, as shown by Witbaard et al (2005).…”