Development, Mortality and Sinking of Copepod Eggs, a Field Investigation

桡足类卵的发育、死亡和下沉，现场调查

• 批准号: 0221202
• 负责人: Charles Miller
• 金额: --
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0221202&HistoricalAwards=false
• 关键词: Development; Mortality; Sinking; Copepod; Eggs

Eggs of free-spawning copepods are reported to have extremely high mortality rates. Typical estimates of losses before hatching exceed 90%. Most planktonic eggs of near-surface spawning plankton sink, rather than rise. Thus, it is expected that embryo age will, on average, increase downward in the water column as numbers sharply decrease. This study will quantify egg abundance as a function of developmental progress, thus producing estimates of egg mortality rates, and to examine the vertical distribution of egg development stage. Sampling will be carried out with MEGAPUMP, an overside, 2 m 3 min -1 pumping system that has nine sequential filters mounted in a carousel and an onboard CTD system. Lowering MEGAPUMP through the water column with the pump off will produce temperature and salinity profiles. Pumping on retrieval will produce a 9-level, stratified abundance profile of 50 mm zooplankton, including the eggs of all but the smallest calanoid copepods. The study will be conducted in the calm waters of Dabob Bay, a fjord arm in Washington State, deploying MEGAPUMP from the UNOLS vessel R/V BARNES. Four cruises will be conducted in each of two years, 2003 and 2004. Two cruises in the first year will be in cooperation with a group at the Univ. of Washington headed by Dr. Bruce Frost. They are studying the mortality imposed on eggs by a diatom diet. Proposed OSU work will complement the UW project, since they do not propose water column sampling of eggs. UW sampling in Dabob Bay is scheduled weekly for February through April, intending to sample before, during and after the reliable diatom bloom that occurs in this fjord in March. The two programs are compatible aboard. Two OSU spring cruises are proposed for 2004, and two summer cruises are proposed in each of 2003 and 2004. In summer, female copepods will still be abundant and reproducing, but the water column will not have abundant diatoms. Target species for both OSU and UW programs will be Calanus pacificus and Metridia pacifica, the dominant free-spawning copepods in Dabob Bay. Usual abundances and fecundities of both species are high enough to produce large numbers of eggs from samples of only a few cubic meters, readily done with MEGAPUMP. These copepods have large, specifically recognizable eggs. Egg development will be classified morphologically and by DNA content, which is a function of cell number. Cell number in these, and at least some other copepods, is around 2000 at hatching. Thus, DNA should increase through 10 doublings and provide a finely divided development stage series. Mortality rates will be calculated from estimates of egg abundance in each stage. Broader Implications: Copepods are the dominant zooplankters in both oceanic and coastal waters. They are a main pipeline from primary production to fish suitable for harvest, often perhaps as the first consumers at the large-animal side of the microbial loop. It is likely that a major part of the transfer in that pipeline is via copepod eggs. For example, copepod eggs and early nauplii are the main food for larvae of North Atlantic cod. Spawning female copepods are not just stocking future generations; they are feeding much of the food web above them. Well quantified egg mortality rates will be data essential to accurate modeling of copepod population dynamics, rates for which few estimates exist. A study in Dabob Bay will be a prelude to studies in more complex coastal and oceanic habitats. The work will contribute to the overall goals of planktology at the present day, as exemplified in the U.S. and International GLOBEC programs. Training of a student by the project will contribute to the future of planktology.

据报道，自由产卵的鸡蛋的死亡率极高。 孵化前损失的典型估计超过90％。 大多数近表面产卵浮游生物的浮游卵，而不是上升。 因此，预计胚胎年龄平均会随着数字急剧下降而在水柱中的平均下降。 这项研究将量化卵丰度，这是发育进步的函数，从而产生卵死亡率的估计，并检查卵发育阶段的垂直分布。 采样将与MegaPump一起进行，MegaPump是一个偏高的2 m 3分钟-1泵送系统，该系统的旋转频率安装在旋转木马和车载CTD系统中。 通过泵关闭泵，通过水柱降低巨型会产生温度和盐度剖面。 泵送的检索将产生9级，分层的丰度剖面，为50毫米浮游动物，包括除最小的calanoid copepods以外的所有卵。该研究将在华盛顿州的峡湾臂达博布湾的平静水域进行，从UNOLS船R/V Barnes部署了Megapump。在2003年和2004年的两年中，将进行四次巡游。第一年将与大学合作进行两次巡游。华盛顿由布鲁斯·弗罗斯特（Bruce Frost）博士领导。他们正在研究通过硅藻饮食对卵施加的死亡率。拟议的OSU工作将补充UW项目，因为它们不建议对鸡蛋进行水柱采样。 Dabob Bay的UW采样定于2月至4月举行，打算在3月在峡湾发生的可靠硅藻之前，期间和之后进行采样。 这两个程序兼容。 2004年提出了两次OSU Spring Cruises，并在2003年和2004年提出了两次夏季巡游。在夏季，女性Copepods仍然很丰富且繁殖，但水柱将没有丰富的硅藻。 OSU和UW计划的目标物种将是Calanus Pacificus和Pacifica Metridia Pacifica，这是Dabob Bay的主要自由产卵脚架。 这两种物种的通常丰度和繁殖力都足够高，可以从只有几立方米的样品中产生大量卵，很容易用Megapump完成。 这些Copepods具有较大的，特别是可识别的鸡蛋。 卵发育将以形态学和DNA含量分类，这是细胞数的函数。 这些细胞号，至少有一些其他Copepods在孵化时约为2000年。 因此，DNA应通过10次加倍增加，并提供细分的开发阶段系列。 死亡率将根据每个阶段的卵丰度的估计来计算。 更广泛的含义：Copepods是海洋和沿海水域中的主要浮游动物。 它们是从初级生产到适合收获的鱼类的主要管道，通常是第一批在微生物环的大动物侧的消费者。 该管道中转移的主要部分可能是通过copepod卵。 例如，Copepod卵和早期的Nauplii是北大西洋鳕鱼幼虫的主要食物。 产卵的女copods不仅仅是子孙后代的库存；他们在上面喂食大部分食物网。 量化良好的鸡蛋死亡率将是对CopePod人口动态的准确建模必不可少的数据，而该模型的估计很少。 在达博布湾的一项研究将是对更复杂的沿海和海洋栖息地的研究的序幕。 如今，这项工作将在当今的总体目标中促进浮游物质的总体目标。该项目对学生培训将有助于浮游生物的未来。