Flow, food supply and acorn barnacle population dynamics

Abstract

While it is widely believed that oceanographic conditions influence benthic filter-feeding organisms, linkages between water column and population processes on rocky shores have been difficult to document. Here we combine laboratory and field studies to explore the relationship between water column conditions and the feeding, growth and population dynamics of the northern acorn barnacle Semibalanus balanoides. S. balanoides feeding behavior in a flow tank was strongly dictated by flow speeds, food concentrations, and temperatures. The percentage of barnacles feeding increased with both flow speed and food concentrations, but was depressed at high temperatures. These patterns were accurately reflected in S. balanoides feeding in the field. Moreover, within and among populat i o n~, variation in barnacle growth over a wide geographic area directly reflected corresponding variation in flow speed, food abundance, and water temperature. Flow effects on barnacles also had conspicuous population consequences. Since barnacle recruitment and growth are both enhanced at high flow speeds, barnacle density-dependent dynamics may often be strongly affected by flow conditions. Our results suggest that water column processes can powerfully affect passive filter feeding organisms on rocky shores and that oceanographic conditions may often leave a strong signature on the distribution, abundance, and dynamics of assemblages of sessile marine organisms.

Gypsum dissolution is not a universal integrator of ‘water motion’

“…Gaylord (1999) measured wave periods of 8 to 18 s in a rocky intertidal location. Gypsum-dissolution techniques are often used in the intertidal zone (e.g., Sanford et al 1994;Leonard et al 1998), and wave period should be considered here as an additional measure that may affect mass-transfer rates. Wave period is directly related to wave frequency (Wave period ϭ 1/wave frequency).…”

Growth rate, condition, and shell shape of Mytilus galloprovincialis: responses to wave exposure

“…Several studies have recorded faster growth and better physiological condition of mussels and other intertidal filter-feeders in exposed compared to sheltered situations (Bertness et al 1991, Robles & Robb 1993, Sanford et al 1994, Dahlhoff & Menge 1996, Leichter & Witman 1997, Sanford & Menge 2001. In South Africa, growth of the indigenous mytilids Aulacomya ater, Choromytilus meridionalis and Perna perna and of the alien Mytilus galloprovincialis is faster in areas of high water circulation than in areas with restricted circulation (van Erkom Schurink & Griffiths 1993).…”

“…In contrast to these negative effects of wave action, high-energy shores experience greater water flow, which is thought to deliver more food to the shore (Bertness et al 1991, Sanford et al 1994, Bustamante & Branch 1996, Dahlhoff & Menge 1996, Sanford & Menge 2001. Since food provides the energy for production, its availability is probably the single most important factor controlling production.…”

Does flow speed also have a direct effect on growth of active suspension‐feeders: An experimental test on oysters

“…Passive suspension-feeders intercept particles that advect past the organism and thus are directly responsive to food flux-the product of concentration and flow speed (Patterson 1980;Muschenheim 1987); growth increases with increasing food concentration and flow speed (Muschenheim 1987;Sanford et al 1994), although excessively high flow speeds threaten damage to the food capture organs and can inhibit feeding and growth (e.g. Okamura 1984).…”