scholarly journals Evolution of organismal stoichiometry in a long-term experiment with Escherichia coli

2017 ◽  
Vol 4 (7) ◽  
pp. 170497 ◽  
Author(s):  
Caroline B. Turner ◽  
Brian D. Wade ◽  
Justin R. Meyer ◽  
Brooke A. Sommerfeld ◽  
Richard E. Lenski

Organismal stoichiometry refers to the relative proportion of chemical elements in the biomass of organisms, and it can have important effects on ecological interactions from population to ecosystem scales. Although stoichiometry has been studied extensively from an ecological perspective, much less is known about the rates and directions of evolutionary changes in elemental composition. We measured carbon, nitrogen and phosphorus content of 12 Escherichia coli populations that evolved under controlled carbon-limited, serial-transfer conditions for 50 000 generations. The bacteria evolved higher relative nitrogen and phosphorus content, consistent with selection for increased use of the more abundant elements. Total carbon assimilated also increased, indicating more efficient use of the limiting element. We also measured stoichiometry in one population repeatedly through time. Stoichiometry changed more rapidly in early generations than later on, similar to the trajectory seen for competitive fitness. Altogether, our study shows that stoichiometry evolved over long time periods, and that it did so in a predictable direction, given the carbon-limited environment.

2015 ◽  
Author(s):  
Caroline B. Turner ◽  
Brian D. Wade ◽  
Justin R. Meyer ◽  
Richard E. Lenski

Organismal stoichiometry refers to the relative proportion of chemical elements in the biomass of organisms, and it can have important effects on ecological interactions from population to ecosystem scales. Although stoichiometry has been studied extensively from an ecological perspective, little is known about rates and directions of evolutionary changes in elemental composition in response to nutrient limitation. We measured carbon, nitrogen, and phosphorus content ofEscherichia colievolved under controlled carbon-limited conditions for 50,000 generations. The bacteria evolved higher relative nitrogen and phosphorus content, consistent with selection for increased use of the more abundant elements. Total carbon assimilated also increased, indicating more efficient use of the limiting element. Altogether, our study shows that stoichiometry evolved over a relatively short time-period, and that it did so in a predictable direction given the carbon-limiting environment.


Nature ◽  
2009 ◽  
Vol 461 (7268) ◽  
pp. 1243-1247 ◽  
Author(s):  
Jeffrey E. Barrick ◽  
Dong Su Yu ◽  
Sung Ho Yoon ◽  
Haeyoung Jeong ◽  
Tae Kwang Oh ◽  
...  

Author(s):  
Yudhistir Reddy ◽  
Dipnarayan Ganguly ◽  
Gurmeet Singh ◽  
Mamidala Harikrishna Prasad ◽  
Paneer Selvam Arumughan ◽  
...  

Author(s):  
Zhen’an Yang ◽  
Wei Zhan ◽  
Lin Jiang ◽  
Huai Chen

As one of the nitrogen (N) limitation ecosystems, alpine meadows have significant effects on their structure and function. However, research on the response and linkage of vegetation-soil to short-term low-level N deposition with rhizosphere processes is scant. We conducted a four level N addition (0, 20, 40, and 80 kg N ha−1 y−1) field experiment in an alpine meadow on the Qinghai-Tibetan Plateau (QTP) from July 2014 to August 2016. We analyzed the community characteristics, vegetation (shoots and roots), total carbon (TC), nutrients, soil (rhizosphere and bulk) properties, and the linkage between vegetation and soil under different N addition rates. Our results showed that (i) N addition significantly increased and decreased the concentration of soil nitrate nitrogen (NO3−-N) and ammonium nitrogen, and the soil pH, respectively; (ii) there were significant correlations between soil (rhizosphere and bulk) NO3−-N and total nitrogen (TN), and root TN, and there was no strong correlation between plant and soil TC, TN and total phosphorus, and their stoichiometry under different N addition rates. The results suggest that short-term low-N addition affected the plant community, vegetation, and soil TC, TN, TP, and their stoichiometry insignificantly, and that the correlation between plant and soil TC, TN, and TP, and their stoichiometry were insignificant.


Author(s):  
Vladimir L. Gavrikov ◽  
◽  
Alexey I. Fertikov ◽  
Evgenii A. Vaganov ◽  

Distribution of chemical elements in tree rings bears important information on various biogeochemical processes. In order to achieve a reliable interpretation of the information, it is necessary to know the degree of variation in the content of chemical elements both at the level of the entire species and at the level of individual trees. The research aims to determine which chemical elements have a stable distribution in the trunks of a number of conifers: Siberian spruce (Picea obovata Ledeb.), Scots pine (Pinus sylvestris L.), Siberian larch (Larix sibirica Ledeb.), and Siberian pine (Pinus sibirica Du Tour). The data for the analysis were obtained on the basis of the long-term experiment in forest growing. The experimental site was laid out in 1971–1972 in the vicinity of Krasnoyarsk by the staff of the Sukachev Institute of Forest of the Siberian Branch of the Russian Academy of Sciences. Before planting the seedlings, the soil ground was mechanically levelled, and thus, sufficiently equal growth conditions were created for all plantings. Cores with a diameter of 12 mm were sampled from three normally developing trees of each species and analyzed using modern X-ray fluorescence methods. Content relative values of elements (counts) were obtained with the Itrax Multiscanner (COX Analytical Systems). The content of elements in the tree rings was characterized by the concentration and reserve of elements. Concentration was calculated as the number of counts per 1 mm2 of the ring area; reserve was calculated as the number of counts over the entire ring area. Each of these variables was defined by the parameters of linear slope in the calendar year series and the standard deviation. The cluster analysis was performed in the 4-dimensional space of the obtained parameters. This allowed determining whether the series of element distributions from different trees and species are grouped. Three elements (Ca, Co, and P) show high stability of distribution parameters in tree rings with no regard to tree species. A number of other elements (Mn, Pb, Cl, Cr, Ni, Sr, and W) are stably grouped depending on the species. The results of the research enable to focus on the study of the elements stably distributed in the conifer trunks. For citation: Gavrikov V.L., Fertikov A.I., Sharafutdinov R.A., Vaganov E.A. Variability in Elemental Composition of Conifer Tree Rings. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 24–37. DOI: 10.37482/0536-1036-2021-6-24-37


2019 ◽  
pp. 119-124
Author(s):  
Brigitta Simon ◽  
Tamás Kucserka ◽  
Angéla Anda

In lakes and wetlands, leaf litter input from the coastal vegetation represents a major nutrient load and plays a basic structural and functional role in several ecosystems. In Hungary, at the banks of lakes and wetlands, Salix and Populus trees are the most common species. In an experiment in Lake Balaton and Kis-Balaton Wetland between 16 November 2017 to and 3 June 2018, the decomposition rates and leaching dynamics of Salix, Populus and mixed leaves (50% Salix and 50% Populus) were investigated. Total nitrogen and phosphorus content of biomass samples were measured at the beginning and end of the experiment for the leaching dynamics experiment. We found that litter mass losses (Salix, Populus and mixed leaves) were not significantly different between the two mesh size litterbags and between Lake Balaton and Kis-Balaton Wetland. Different amounts of the total nitrogen and phosphorus leaching from Salix, Populus and mixed leaves were detected. The total nitrogen contents of the plant samples were around 8-18% at the end of the investigated period. Slightly higher values were measured compared to phosphorous (27-29%).


Sign in / Sign up

Export Citation Format

Share Document