{"221221":{"#nid":"221221","#data":{"type":"news","title":"Research Shows Influence of Temporal Niches in Maintaining Biodiversity","body":[{"value":"\u003Cp\u003EBy studying rapidly evolving bacteria as they diversify and compete under varying environmental conditions, researchers have shown that temporal niches are important to maintaining biodiversity in natural systems. The research is believed to be the first experimental demonstration of temporal niche dynamics promoting biodiversity over evolutionary time scales.\u003C\/p\u003E\u003Cp\u003EThe temporal niches \u2013 changes in environmental conditions that occur during specific periods of time \u2013 promoted frequency-dependent selection within the bacterial communities and positive growth of new mutants. They played a vital role in allowing diversity among bacterial phenotypes to persist.\u003C\/p\u003E\u003Cp\u003EThe research provides new insights into the factors that promote species coexistence and diversity in natural systems. Understanding the mechanisms governing the origin and maintenance of biodiversity is important to scientists studying the roles of both ecology and evolution in natural systems.\u003C\/p\u003E\u003Cp\u003E\u201cThis study provides the first experimental evidence showing the impact of temporal niche dynamics on biodiversity evolution,\u201d said Lin Jiang, co-author of the paper and an associate professor in the School of Biology at the Georgia Institute of Technology. \u201cOur laboratory results in bacteria can potentially explain the diversity dynamics that have been observed for other organisms over evolutionary time.\u201d\u003C\/p\u003E\u003Cp\u003EThe research, which was supported by the National Science Foundation, was published July 9 in the journal \u003Cem\u003ENature Communications\u003C\/em\u003E.\u003C\/p\u003E\u003Cp\u003EIn experimental manipulation of the bacterium \u003Cem\u003EPseudomonas fluorescens\u003C\/em\u003E, the researchers showed that alternating environmental conditions in 24-hour cycles strongly influences biodiversity dynamics by helping to maintain closely-related phenotypes that might otherwise be lost to competition with a dominant phenotype. The experiment followed the bacteria through more than 200 generations over a period of nearly two weeks.\u003C\/p\u003E\u003Cp\u003EIn the laboratory, Jiang and graduate student Jiaqi Tan established communities of the bacterium in test tubes called microcosms. In designing the experiments, they collaborated with Colleen Kelly, a senior research associate in the Department of Zoology at the University of Oxford.\u003C\/p\u003E\u003Cp\u003E\u201cYou begin with one phenotype, and within two days, you might have two or three different phenotypes,\u201d said Jiang. \u201cThe system can do this in a matter of days.\u201d\u003C\/p\u003E\u003Cp\u003EThrough a 12-day experimental period, the researchers subjected one group of cultures to 24-hour periods in which they were alternately allowed to grow undisturbed and shaken vigorously. To control for the impact of starting conditions, cultures within those two groups were chosen to begin with a period of static growth, while others began with a period of shaken growth. Finally, groups of control cultures were grown under continuous shaking or continuous static conditions.\u003C\/p\u003E\u003Cp\u003EDuring the study, the researchers periodically measured the population sizes of each phenotype present in each culture. Cultures subjected to alternating shaking and static conditions produced the highest level of diversity among the closely-related bacteria, which is often studied because it diversifies so rapidly.\u003C\/p\u003E\u003Cp\u003E\u201cStatic conditions promoted diversification,\u201d Jiang explained. \u201cBut the shaking tended to maintain the diversity that had evolved. Both conditions were essential for high biodiversity.\u201d\u003C\/p\u003E\u003Cp\u003EIn experiments, the ancestral bacterial phenotype, which is known as \u201csmooth morph,\u201d quickly diversifies and generates two niche-specialists, known as \u201cwrinkled spreader\u201d and \u201cfuzzy spreader.\u201d Those, in turn, diversify into additional phenotypes. Competition for oxygen in the microcosms in which the bacteria grow is believed to drive the diversification; shaking the microcosms changes the levels of oxygen available to each phenotype. Because different phenotype groups inhabit different sections of the container, the shaking eliminated the preferred niches of some phenotypes.\u003C\/p\u003E\u003Cp\u003EThe diversification in the microcosms experiencing constant shaking was much slower than in static microcosms. In microcosms experiencing temporal niche dynamics \u2013 the alternating shaking and non-shaking periods \u2013 the diversity increased rapidly and was maintained longer than in the other environments. The researchers found that the two different temporal niche dynamics environments \u2013 which differed only in their starting conditions \u2013 both produced richer biodiversity than those environments without it.\u003C\/p\u003E\u003Cp\u003EWhile the diversification occurred rapidly over a period of four days, the decline in the number of phenotypes due to natural competition took longer. Some of the phenotypes were ultimately excluded through the competitive processes.\u003C\/p\u003E\u003Cp\u003E\u201cDiversity typically increases with time, then plateaus,\u201d said Jiang. \u201cWithout temporal niche, diversity tends to decline. Temporal niche allows a greater diversity to be maintained over time than would be possible otherwise.\u201d\u003C\/p\u003E\u003Cp\u003EThough the study focused on rapidly diversifying bacteria, the researchers believe it may have broader implications. The general theory of temporal niche dynamics was developed with more complex organisms, such as plants and corals, in mind.\u003C\/p\u003E\u003Cp\u003E\u201cThe mechanisms that promote biodiversity, which we call frequency-dependent selection, are very common in species,\u201d said Tan. \u201cAs long as you have a strong intra-species competition within the populations, you are expected to see this frequency-dependent selection. Based on this most common mechanism that we find in this system, there are implications for other ecosystems.\u201d\u003C\/p\u003E\u003Cp\u003EFor the future, the researchers would like to study the effects of combining spatial and temporal niches in evolution.\u003C\/p\u003E\u003Cp\u003E\u201cFrom this experiment, we know that temporal niche can maintain biodiversity,\u201d said Tan. \u201cSimilarly, we want to manipulate spatial diversity to see if heterogeneity in the spatial scale can affect the maintenance of biodiversity.\u201d\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThis research was supported by the National Science Foundation under grants DEB-1120281 and DEB-1257858. Any opinions expressed are those of the authors and do not necessarily represent the official views of the National Science Foundation.\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Jiaqi Tan, Colleen K. Kelly and Lin Jiang, \u003Cem\u003E\u201cTemporal niche promotes biodiversity during adaptive radiation,\u201d\u003C\/em\u003E (Nature Communications, 2013). \u003Ca href=\u0022http:\/\/dx.doi.org\/10.1038\/ncomms3102\u0022 title=\u0022http:\/\/dx.doi.org\/10.1038\/ncomms3102\u0022\u003Ehttp:\/\/dx.doi.org\/10.1038\/ncomms3102\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EBy studying rapidly evolving bacteria as they diversify and compete under varying environmental conditions, researchers have shown that temporal niches are important to maintaining biodiversity in natural systems. The research is believed to be the first experimental demonstration of temporal niche dynamics promoting biodiversity over evolutionary time scales.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have shown that temporal niches are important to maintaining biodiversity in natural systems."}],"uid":"27303","created_gmt":"2013-07-08 21:42:58","changed_gmt":"2016-10-08 03:14:30","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2013-07-09T00:00:00-04:00","iso_date":"2013-07-09T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"221161":{"id":"221161","type":"image","title":"Temporal niche","body":null,"created":"1449243508","gmt_created":"2015-12-04 15:38:28","changed":"1475894888","gmt_changed":"2016-10-08 02:48:08","alt":"Temporal niche","file":{"fid":"197263","name":"temporal-niche11.jpg","image_path":"\/sites\/default\/files\/images\/temporal-niche11_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/temporal-niche11_0.jpg","mime":"image\/jpeg","size":1245280,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/temporal-niche11_0.jpg?itok=DfET_5_Z"}},"221171":{"id":"221171","type":"image","title":"Temporal niche2","body":null,"created":"1449243516","gmt_created":"2015-12-04 15:38:36","changed":"1475894888","gmt_changed":"2016-10-08 02:48:08","alt":"Temporal niche2","file":{"fid":"197264","name":"temporal-niche41.jpg","image_path":"\/sites\/default\/files\/images\/temporal-niche41_1.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/temporal-niche41_1.jpg","mime":"image\/jpeg","size":1181046,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/temporal-niche41_1.jpg?itok=8bKjDnni"}},"221191":{"id":"221191","type":"image","title":"Temporal niche3","body":null,"created":"1449243516","gmt_created":"2015-12-04 15:38:36","changed":"1475894888","gmt_changed":"2016-10-08 02:48:08","alt":"Temporal niche3","file":{"fid":"197266","name":"temporal-niche61.jpg","image_path":"\/sites\/default\/files\/images\/temporal-niche61_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/temporal-niche61_0.jpg","mime":"image\/jpeg","size":1189802,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/temporal-niche61_0.jpg?itok=CNuLTt4F"}},"221201":{"id":"221201","type":"image","title":"Temporral niche4","body":null,"created":"1449243516","gmt_created":"2015-12-04 15:38:36","changed":"1475894888","gmt_changed":"2016-10-08 02:48:08","alt":"Temporral niche4","file":{"fid":"197267","name":"temporal-niche97.jpg","image_path":"\/sites\/default\/files\/images\/temporal-niche97_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/temporal-niche97_0.jpg","mime":"image\/jpeg","size":1023166,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/temporal-niche97_0.jpg?itok=fD8sf_xV"}},"221211":{"id":"221211","type":"image","title":"Temporal niche5","body":null,"created":"1449243516","gmt_created":"2015-12-04 15:38:36","changed":"1475894891","gmt_changed":"2016-10-08 02:48:11","alt":"Temporal niche5","file":{"fid":"197268","name":"temporal-niche211.jpg","image_path":"\/sites\/default\/files\/images\/temporal-niche211_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/temporal-niche211_0.jpg","mime":"image\/jpeg","size":1031600,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/temporal-niche211_0.jpg?itok=WogEySBI"}}},"media_ids":["221161","221171","221191","221201","221211"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"146","name":"Life Sciences and Biology"}],"keywords":[{"id":"7077","name":"bacteria"},{"id":"69201","name":"biodivresity"},{"id":"277","name":"Biology"},{"id":"20751","name":"Lin Jiang"},{"id":"69191","name":"temporal niche"}],"core_research_areas":[{"id":"39441","name":"Bioengineering and Bioscience"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}