Do Top-Down and Bottom-Up Controls Interact to Exclude N-Fixing Cyanobacteria From the Plankton of Estuaries?

自上而下和自下而上的控制是否相互作用以排除河口浮游生物中的固氮蓝藻？

基本信息

批准号：
9527405
负责人：
Robert Howarth
金额：
$ 40万
依托单位：
Cornell Univ - State: AWDS MADE PRIOR MAY 2010
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1996
资助国家：
美国
起止时间：
1996-09-01 至 2000-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527405&HistoricalAwards=false
关键词：
Do Top Down Bottom Up

项目摘要

Author: rwh2@cornell.edu (Robert W. Howarth) at NOTE Date: 3/26/96 12:08 PM Priority: Normal TO: cdahm at nsf2 CC: rmm3@cornell.edu at NOTE CC: 73753.2331@compuserve.com at NOTE Subject: Abstract for DEB 9527405 ------------------------------- Message Contents ------------------------------- Hi Cliff -- Here is my stab at the abstract you requested. Mike Pace and I are still working on the budget. Bob DEB-95-27405: "Do top-down and bottom-up controls interact to exclude nitrogen-fixing cyanobacteria from the plankton of estuaries?" Eutrophication and phytoplankton production are frequently limited by nitrogen in estuaries and by phosphorus in lakes. One reason for this striking differences is a difference in nitrogen fixation. In lakes when nitrogen availability is low, nitrogen-fixing organisms bloom and help alleviate the nitrogen deficit by fixing molecular nitrogen into biologically available forms. In most estuaries, no such response occurs. This proposal tests the hypothesis that low availabilities of trace metals (Fe and Mo) in estuaries relative to lakes leads to slow growth rates of nitrogen-fixing organisms, leaving these organisms vulnerable to consumption by animals, and thereby preventing nitrogen fixation. In preliminary experiments with tanks full of seawater, the investigators successfully grew nitrogen fixing organisms by keeping animal populations low. This was the first time nitrogen-fixing organisms of the sort common to lakes were found in estuarine water anywhere in North America. The new research will build on these tank studies to more completely test the hypothesized difference between lakes and estuaries.

作者：rwh2@cornell.edu (Robert W. Howarth)，注释日期：3/26/96 12:08 PM 优先级：正常收件人：nsf2 的 cdahm 抄送：rmm3@cornell.edu 注释抄送：73753.2331@compuserve.com at 注意主题：DEB 9527405 摘要 ---------------------------------------------- 消息内容 --------- ---------------------- 嗨悬崖——这是我对您要求的摘要的尝试。迈克·佩斯和我仍在制定预算。 Bob DEB-95-27405：“自上而下和自下而上的控制是否相互作用，以排除河口浮游生物中的固氮蓝藻？” 富营养化和浮游植物的生产经常受到河口氮和湖泊磷的限制。造成这种显着差异的原因之一是固氮作用的差异。在氮可用性较低的湖泊中，固氮生物大量繁殖，通过将分子氮固定为生物可利用的形式来帮助缓解氮缺乏。在大多数河口，不会发生这样的反应。该提案检验了这样的假设：河口相对于湖泊而言微量金属（铁和钼）的利用率较低，导致固氮生物的生长速度缓慢，使这些生物容易被动物消耗，从而阻碍固氮。在充满海水的水箱的初步实验中，研究人员通过保持较低的动物数量成功地培养了固氮生物。这是首次在北美任何地方的河口水中发现湖泊常见的固氮生物。新的研究将建立在这些水池研究的基础上，以更全面地测试湖泊和河口之间的假设差异。