Top-down impact through a bottom-up mechanism: the effect of limpet grazing on growth, productivity and carbon allocation of Zostera marina L. (eelgrass)
Top-down impact through a bottom-up mechanism: the effect of limpet grazing on growth, productivity and carbon allocation of Zostera marina L. (eelgrass)
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通过自下而上的机制实现自上而下的影响：帽贝放牧对大叶藻（鳗草）生长、生产力和碳分配的影响
DOI：
10.1007/bf00333949
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发表时间：
1996
期刊：
影响因子：
2.7
通讯作者：
R. S. Alberte
中科院分区：
文献类型：
--
作者：
R. Zimmerman;D. Kohrs;R. S. Alberte
来自加州南部的高密度（高达10个枝条-1）的一种长叶鳗草帽贝[Tectura elgrass limpet（Berry）]的不寻常的出现与潮下带Zostera marina L.加州蒙特雷湾的一片草地。一些海藻帽贝吃鳗草叶片富含叶绿体的表皮，但不知道会影响海草的生长或生产力。我们评估了在自然光照的围隔生态系统中，在自然密度（8±2枝-1）下放牧帽贝45天对鳗草生产力的影响。放牧植物的生长速率、碳储量、根系增殖和净光合作用比未放牧植物低50-80%，但生物量比呼吸不受影响。放牧植物维持正碳平衡所需的光照饱和光合作用日周期（Hsat）接近13.5h，而未放牧植物为5-6 h。分配到根的未放牧植物的碳的量是800%高于放牧植物。通过啃食富含叶绿素的表皮，T.在其他方面的光充足的环境中生长的鳗草中，Escherita诱导的碳限制。T.尽管这种帽贝消耗很少的植物生物量，但它可能对东北太平洋的鳗草生产和种群动态产生重大影响。这种相互作用是一个戏剧性的例子，自上而下的控制（放牧/捕食）的鳗鱼草生产力和生存通过自下而上的机制（光合作用的限制）。
The unusual appearance of a commensal eelgrass limpet [Tectura depicta (Berry)] from southern California at high density (up to 10 shoot−1) has coincided with the catastrophic decline of a subtidal Zostera marina L. meadow in Monterey Bay, California. Some commensal limpets graze the chloroplast-rich epidermis of eelgrass leaves, but were not known to affect seagrass growth or productivity. We evaluated the effect on eelgrass productivity of grazing by limpets maintained at natural densities (8±2 shoot−1) in a natural light mesocosm for 45 days. Growth rates, carbon reserves, root proliferation and net photosynthesis of grazed plants were 50–80% below those of ungrazed plants, but biomass-specific respiration was unaffected. The daily period of irradiance-saturated photosynthesis (Hsat) needed to maintain positive carbon balance in grazed plants approached 13.5 h, compared with 5–6 h for ungrazed plants. The amount of carbon allocated to roots of ungrazed plants was 800% higher than for grazed plants. By grazing the chlorophyll-rich epidermis, T. depicta induced carbon limitation in eelgrass growing in an other-wise light-replete environment. Continued northward movement of T. depicta, may have significant impacts on eelgrass production and population dynamics in the northeast Pacific, even thought this limpet consumes very little plant biomass. This interaction is a dramatic example of top-down control (grazing/predation) of eelgrass productivity and survival operating via a bottom-up mechanism (photosynthesis limitation).