Ecophysiological and Trophic Implications of Light-Stimulated Amino Acid Utilization in Marine Picoplankton

Author:

Paerl Hans W.1

Affiliation:

1. Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina 28557

Abstract

By using microautoradiography, light-stimulated utilization of dissolved amino acids for natural marine phytoplankton assemblages was demonstrated. The <2-μm-size (diameter) picoplankton, known to be a dominant fraction of marine primary production, revealed a widespread capability for this process. Autofluorescent (chlorophyll a -containing) picoplankton and some larger phytoplankton from diverse oceanic locations, as well as isolates of the representative cyanobacterial picoplankton Synechococcus spp. (WH7803, WH8101), showed light-stimulated incorporation of amino acids at trace concentrations. Dark-mediated amino acid utilization was dominated by nonfluorescent bacterial populations. Among autofluorescent picoplankton, light-stimulated exceeded dark-mediated amino acid incorporation by 5 to 75%; light-stimulated amino acid incorporation was only partially blocked by the photosystem II inhibitor 3(3,4-dichloro-phenyl)-1,1-dimethy-lurea (2 × 10 -5 M), suggesting a photoheterotrophic incorporation mechanism. Parallel light versus dark incubations with glucose and mannitol indicated a lack of light-stimulated utilization of these nonnitrogenous compounds. Since marine primary production is frequently nitrogen limited, light-mediated auxotrophic utilization of amino acids and possibly other dissolved organic nitrogen (DON) constituents may represent exploitation of the relatively large DON pool in the face of dissolved inorganic nitrogen depletion. This process (i) increases the efficiency of DON retention at the base of oceanic food webs and (ii) may in part be responsible for relatively high rates of picoplankton production under conditions of chronic dissolved inorganic nitrogen limitation. Picoplanktonic recycling of organic matter via this process has important ramifications with respect to trophic transfer via the “microbial loop.”

Publisher

American Society for Microbiology

Subject

Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology

Reference35 articles.

1. Novel phycoerythrins in marine Synechococcus spp.: characterization and evolutionary and ecological implications;Alberte R. S.;Plant Physiol.,1984

2. Size distribution and activity of marine microheterotrophs;Azam F.;Limnol. Oceanogr.,1977

3. Billen G. 1981. Heterotrophic utilization and regeneration of nitrogen p. 315-335. In J. E. Hobbie and P. J. L. B. Williams (ed.) Heterotrophic activity in the sea. Plenum Publishing Corp. New York.

4. Carpenter E. J. and D. G. Capone (ed.). 1983. Nitrogen in the marine environment. Academic Press Inc. New York.

5. Utilization of urea by some marine phytoplankters;Carpenter E. J.;Limnol. Oceanogr.,1972

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3