Cobalt as a potential limiting factor for heterocyst frequency in nitrogen‐limited Aphanizomenon and Dolichospermum: Evidence from experimental and field studies

Author:

Shah Purnank1ORCID,Venkiteswaran Jason J.1ORCID,Molot Lewis A.2ORCID,Higgins Scott N.3ORCID,Schiff Sherry L.4ORCID,Baulch Helen M.5ORCID,Zastepa Arthur6ORCID

Affiliation:

1. Department of Geography and Environmental Studies Wilfrid Laurier University Waterloo Ontario Canada

2. Faculty of Environmental and Urban Change York University Toronto Ontario Canada

3. International Institute for Sustainable Development‐Experimental Lakes Area Winnipeg Manitoba Canada

4. Department of Earth and Environmental Sciences University of Waterloo Waterloo Ontario Canada

5. School of Environment and Sustainability and Global Institute for Water Security, Saskatoon University of Saskatchewan Saskatoon Saskatchewan Canada

6. Canada Centre for Inland Waters Environment Canada and Climate Change Burlington Ontario Canada

Abstract

Abstract Evidence suggests that low cobalt (Co) may limit heterocyst frequency (HF) in filamentous diazotrophic cyanobacteria. Therefore, the effect of three Co concentrations on HF in four species in the genera Aphanizomenon and Dolichospermum was examined in N‐depleted (N was not added) culture. Long‐term HF data were also analysed in experimentally fertilised N‐limited Lake 227. HF ranges and means at 0.17, 17, and 170 nmol Co/L were 4.1%–5.7% (4.6%), 5.4%–7.4% (6.4%), and 5.9%–9.3% (7.4%), respectively, after 11 days of growth in batch cultures suggesting that Co plays a role in regulating HF. HF at 0.17 nmol/L was significantly different from HF at the two higher concentrations in all species implicating Co in heterocyst differentiation. However, growth rates and final biovolume yields were not significantly affected by Co in any of the species. Applying the ratio of total phosphorus (TP)/Co in culture media (106) at 0.17 nmol Co/L to an N‐limited system implies that dissolved Co would have to be less than 1 pmol/L to severely limit HF at 1 μmol TP/L. This Co concentration is much lower than dissolved Co in Lake 227 during an Aphanizomenon skujae bloom with 1 μmol TP/L in 2017. Furthermore, Co increased from 0.7 to 2.0 nmol/L simultaneously increasing with HF and cyanobacteria biomass suggesting that Co probably did not limit HF and bloom biomass in Lake 227. Mean summer HFs in Lake 227 during 2000–2020 were 3.4% (epilimnion) and 4.0% (metalimnion), similar to HF at the lowest Co in the cultures. However, HF was significantly higher after 2015 following a shift in dominant bloom species from A. schindlerii to the smaller A. skujae. Calculations suggest that the decrease in cell size may have prompted a higher HF in A. skujae in order to fix an amount of N per unit biomass similar to that fixed by the larger A. schindlerii. Thus, two previously unidentified factors, Co and cell size, can be added to the list of factors that affect HF.

Funder

Canada First Research Excellence Fund

Natural Sciences and Engineering Research Council of Canada

Publisher

Wiley

Reference106 articles.

1. N2-fixation, ammonium release and N-transfer to the microbial and classical food web within a plankton community

2. Random sampling of cyanobacterial diversity from five locations within eastern Himalayan biodiversity hot spot;Ahad A.;International Journal of Advanced Research in Biological Sciences,2015

3. Iron Regulation of Growth and Heterocyst Formation in the Nitrogen Fixing Cyanobacterium Nostoc sp. PCC 7120

4. Aphanizomenon sp. from lake Trichonis, Hellas (Greece). A taxonomic consideration in relation to morphological and ecological parameters;Anagnostidis K.;Archiv für Hydrobiologie, Supplement,1988

5. Trace metal metabolism in plants

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