Milligan KL, DeWreede RE
Department of Botany, The University of British Columbia, B.C. V6T 1Z4, Vancouver, Canada
J Exp Mar Biol Ecol. 2000 Nov 20;254(2):189-209. doi: 10.1016/s0022-0981(00)00279-3.
Biomechanical models that describe physical and biological interactions on wave-exposed shores typically assume that a species' attachment properties are similar between seasons and sites. We tested this assumption using Hedophyllum sessile to investigate how macroalgal biomechanical attachment properties vary with developmental stage, substratum-type, season, and wave-exposure. Hedophyllum sessile is an intertidal kelp species that is able to survive in wave-exposed areas in the Northeast Pacific. For both juveniles and adults, holdfast attachment force and strength were measured at a wave-exposed and wave-protected site in Barkley Sound, British Columbia, Canada. Substratum and wave-exposure effects on attachment properties were tested in juvenile populations. Adult populations were sampled prior to (in July 1996) and after (in November 1996) a series of storms. Site and seasonal wave-exposure effects on attachment properties were tested in these adult populations. Comparisons to known attachment properties of other temperate macroalgal species were also made. Causes for these patterns are discussed but were not isolated in these studies. Juveniles' attachment properties differed on different substrata types and between wave-exposures, with the highest attachment forces and the most attached juveniles in articulated coralline algal turfs. Adult attachment is firm ( approximately 100 N), but relatively weak ( approximately 0.07 MNm(-2)). Adult attachment did not vary with site wave-exposure, but there was a shift within each site to more resistant holdfasts after a series of early winter storms. Seasonal increases in storm swells correlated to more thallus tattering and selected against large, loose holdfasts. The data presented here suggest that results from holdfast attachment field studies in one season cannot be extrapolated to another due to a complex set of dynamics. This is the first documentation of seasonal patterns in macroalgal attachment properties.
描述海浪冲击海岸上物理和生物相互作用的生物力学模型通常假定，一个物种的附着特性在不同季节和地点之间是相似的。我们以固着叶藻为研究对象对这一假设进行了验证，以探究大型藻类的生物力学附着特性如何随发育阶段、基质类型、季节和海浪冲击程度而变化。固着叶藻是一种潮间带海带物种，能够在东北太平洋海浪冲击的区域生存。对于幼体和成体，我们在加拿大不列颠哥伦比亚省巴克利湾一个海浪冲击区域和一个海浪遮蔽区域测量了其固着器的附着力和强度。在幼体群体中测试了基质和海浪冲击对附着特性的影响。在一系列风暴来临之前（1996年7月）和之后（1996年11月）对成体群体进行了采样。在这些成体群体中测试了地点和季节性海浪冲击对附着特性的影响。还与其他温带大型藻类物种已知的附着特性进行了比较。文中讨论了这些模式的成因，但在这些研究中并未明确找出其原因。幼体在不同的基质类型上以及在不同的海浪冲击程度下附着特性有所不同，在有节珊瑚藻草皮中附着力最高且附着的幼体最多。成体的附着较为牢固（约100牛），但相对较弱（约0.07兆牛/平方米）。成体的附着情况不会因地点的海浪冲击程度而变化，但在每个地点，经过一系列初冬风暴后，固着器变得更具抗性。风暴涌浪的季节性增加与更多的藻体破碎相关，不利于大型、松散的固着器。此处呈现的数据表明，由于存在一系列复杂的动态变化，一个季节中固着器附着实地研究的结果不能外推至另一个季节。这是首次记录大型藻类附着特性的季节性模式。
