Collaborative Research: Initiation and Maintenance of Population Maxima of the Ctenophore Mnemiopsis leidyi in Northern Coastal Waters

在北部沿海水域，雷氏栉水母种群最大值的产生和维持在纳拉甘西特湾，该河口位于该物种地理分布的北部边界，近十年来，雷氏栉水母种群的峰值浓度大幅增加。在海湾水温较早变暖的年份，记忆藻脉冲的季节时间也从夏末转移到早春。这种暂时引入的重大生态后果可能是巨大的。在该地区鱼类产卵的高峰期，记忆藻数量丰富。2000年春季和夏季浮游动物资源严重枯竭。类似的季节性和物种丰度变化很可能发生在东北部的其他河口。尽管大脉冲的栉水母在生态上具有明显的重要性，但了解导致种群快速增长的条件的定量基础是有限的。虽然温度和食物供应最终肯定是控制该物种生长和繁殖的主要变量，但关于越冬种群的繁殖或有利于春季幼虫生长的条件的信息很少。在这项研究中，研究人员将在整个年度周期内对记忆藻进行实地和实验室研究，以确定温度、食物供应和食物质量对繁殖率和幼虫生长的影响。微型浮游动物的作用，只在以前的两个实验室研究中讨论，将在实地和实验室组成部分中充分讨论。最近观察到的纳拉甘西特湾地区在冬季维持了意想不到的大量记忆藻种群，以及种群脉冲延迟到春季的地区将进行比较。将收集和审查水文数据，以了解自然因素对人口增长的直接和间接影响，包括热分层在人口脉动产生中的作用。鉴于有证据表明雷氏孟米opis的季节性或地理入侵对生态系统具有破坏性影响，以及在其地理范围的北部边缘对该物种的研究数量有限，本研究的理由是令人信服的。本研究收集的温度和食物对雷氏夜蛾幼虫和成虫影响的详细定量信息，将大大促进我们对该物种种群脉动启动和维持所需因素的理解。

Initiation and Maintenance of Population Maxima of the Ctenophore Mnemiopsis leidyi in Northern Coastal WatersSubstantial increases in peak concentrations of the ctenophore Mnemiopsis leidyi have occurred in the last decade in Narragansett Bay, an estuary at the northern boundary of the geographic distribution of this species. The seasonal timing of Mnemiopsis pulses has also shifted from late summer to early spring during years with earlier warming of bay water temperatures. Significant ecological consequences of this temporal introduction are potentially great. Mnemiopsis is now abundant during the peak period of fish spawning in the region. Severely depleted stocks of zooplankton have been observed in spring and summer of 2000. Similar changes in seasonality and abundance of the species are likely to be occurring in other estuaries in the northeast. Despite the clear ecological importance of large pulses of ctenophores, the quantitative basis for understanding conditions giving rise to rapid population increases is limited. While temperature and food supply must ultimately be dominant variables controlling growth and reproduction of this species, there is little information about reproduction of over-wintering populations or conditionswhich favor growth of larvae in spring. In this study the investigators will conduct field and laboratory studies of Mnemiopsis over the full annual cycle to determine effects of temperature, food supply and food quality on reproductive rates and larval growth. The role of microzooplankton, addressed in only two previous laboratory studies will be fully addressed in both field and laboratory components. Areas of Narragansett Bay which have recently been observed to sustain unexpectedly large population of Mnemiopsis in winter, as well as areas in which populations pulses are delayed until spring will be compared. Hydrographic data will be collected and examined for both direct and indirect effects of physical factors on population growth, including the role of thermal stratification in population pulse initiation. Given the evidence for disruptive effects on ecosystems of seasonal or geographic invasions of Mnemiopis leidyi and the limited number of studies of this species at the northern edge of its geographic range, justification for this study is compelling. Quantitative information on the influence of temperature and food on both larval and adult M. leidyi at the level of detail collected in this study will significantly advance our understanding of factors required for initiation and maintenance of population pulses of this species.