Gómez-Gutiérrez J, Palomares-García R, Hernández-Trujillo S, Carballido-Carranza A
Departamento de Plancton y Ecología Marina, Centro Interdisciplinario de Ciencias Marinas, Apartado Postal 592, C.P. 23000 La Paz, Baja California Sur, México.
Rev Biol Trop. 2001 Jun;49(2):545-57.
The zooplankton community structure, including copepods, euphausiids, chaetognaths, and decapod larvae, was monitored during six circadian cycles using Bongo net (500 microns mesh net) samples from Bahía Magdalena, on the southwest coast of Baja California, México. Samples were obtained during three oceanographic surveys (March, July, and December 1996) to describe the changes in the zooplankton community structure throughout the main mouth of Bahía Magdalena. The zooplankton community structure showed strong changes with a close relation to environmental conditions. During March, a well-mixed water column with low temperature and salinity indicated an influence of the California Current water and local upwelling processes. During July, temperature increased and a wide salinity range was recorded. The stratification of the water column was intense during summer, enhancing the thermocline. The highest temperatures and salinity were recorded in December, related to the presence of the Costa Rica Coastal Current (CRCC). The thermocline deepened as water temperature increased. A typical temperate community structure with low specific richness dominated by Calanus pacificus, Nyctiphanes simplex, and Acartia clausi and high zooplankton biomass (average 9.3 and 5.5 ml 1000 m-3 respectively) during March and July shifted to a more complex tropical community structure with a low zooplankton biomass in December (average 0.37 ml 1000 m-3). The mouth of Bahía Magdalena has a vigorous exchange of water caused by tidal currents. The zooplankton community structure was not significantly different between the central part of Bahía Magdalena and the continental shelf outside the bay for all months. The results suggest a more dynamic inside-outside interaction of zooplankton assemblages than first thought.
利用邦戈网（500微米网目网）采集来自墨西哥下加利福尼亚西南海岸马格达莱纳湾的样本，在六个昼夜周期内对包括桡足类、磷虾类、毛颚类和十足目幼体在内的浮游动物群落结构进行了监测。样本是在三次海洋学调查（1996年3月、7月和12月）期间获取的，以描述整个马格达莱纳湾主要入海口浮游动物群落结构的变化。浮游动物群落结构显示出强烈变化，且与环境条件密切相关。3月期间，水柱充分混合，温度和盐度较低，表明受加利福尼亚洋流和当地上升流过程的影响。7月，温度升高，记录到较宽的盐度范围。夏季水柱分层强烈，增强了温跃层。12月记录到最高温度和盐度，这与哥斯达黎加沿岸流（CRCC）的存在有关。随着水温升高，温跃层加深。3月和7月以太平洋哲水蚤、简单磷虾和克氏纺锤水蚤为主、物种丰富度较低且浮游动物生物量较高（分别平均为9.3和5.5毫升/1000立方米）的典型温带群落结构，在12月转变为浮游动物生物量较低（平均0.37毫升/1000立方米）的更为复杂的热带群落结构。马格达莱纳湾入海口因潮流导致水体有活跃的交换。在所有月份中，马格达莱纳湾中部和湾外大陆架的浮游动物群落结构没有显著差异。结果表明，浮游动物组合的内外相互作用比最初认为的更具动态性。
