<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Robinson, David M.</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author><author><style face="normal" font="default" size="100%">Wang, Zhong</style></author><author><style face="normal" font="default" size="100%">Cristina D. Takacs-Vesbach</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Antarctic lake viromes reveal potential virus associated influences on nutrient cycling in ice-covered lakes</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Microbiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">limnology</style></keyword><keyword><style  face="normal" font="default" size="100%">metagenomics</style></keyword><keyword><style  face="normal" font="default" size="100%">virus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2024</style></year><pub-dates><date><style  face="normal" font="default" size="100%">09/2024</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1422941/full</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">15</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The McMurdo Dry Valleys (MDVs) of Antarctica are a mosaic of extreme habitats which are dominated by microbial life. The MDVs include glacial melt holes, streams, lakes, and soils, which are interconnected through the transfer of energy and flux of inorganic and organic material via wind and hydrology. For the first time, we provide new data on the viral community structure and function in the MDVs through metagenomics of the planktonic and benthic mat communities of Lakes Bonney and Fryxell. Viral taxonomic diversity was compared across lakes and ecological function was investigated by characterizing auxiliary metabolic genes (AMGs) and predicting viral hosts. Our data suggest that viral communities differed between the lakes and among sites: these differences were connected to microbial host communities. AMGs were associated with the potential augmentation of multiple biogeochemical processes in host, most notably with phosphorus acquisition, organic nitrogen acquisition, sulfur oxidation, and photosynthesis. Viral genome abundances containing AMGs differed between the lakes and microbial mats, indicating site specialization. Using procrustes analysis, we also identified significant coupling between viral and bacterial communities (&lt;i&gt;p&lt;/i&gt; = 0.001). Finally, host predictions indicate viral host preference among the assembled viromes. Collectively, our data show that: (i) viruses are uniquely distributed through the McMurdo Dry Valley lakes, (ii) their AMGs can contribute to overcoming host nutrient limitation and, (iii) viral and bacterial MDV communities are tightly coupled.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author><author><style face="normal" font="default" size="100%">Popson, Devon</style></author><author><style face="normal" font="default" size="100%">Pereira, Rochelle</style></author><author><style face="normal" font="default" size="100%">Dolhi-Binder, J</style></author><author><style face="normal" font="default" size="100%">Teufel, Amber G.</style></author><author><style face="normal" font="default" size="100%">Li, Wei</style></author><author><style face="normal" font="default" size="100%">Kalra, Isha</style></author><author><style face="normal" font="default" size="100%">Sherwell, Shasten S.</style></author><author><style face="normal" font="default" size="100%">Reynebeau, Emily</style></author><author><style face="normal" font="default" size="100%">Cristina D. Takacs-Vesbach</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sentinel protist taxa of the McMurdo Dry Valley lakes, Antarctica: A review</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Ecology and Evolution</style></secondary-title><short-title><style face="normal" font="default" size="100%">Front. Ecol. Evol.</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">Disturbance</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valley lakes</style></keyword><keyword><style  face="normal" font="default" size="100%">phytoplankton</style></keyword><keyword><style  face="normal" font="default" size="100%">protist</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2024</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2024</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.frontiersin.org/articles/10.3389/fevo.2024.1323472</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">1323472</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;High-latitude meromictic lakes such as those in the Antarctic McMurdo Dry Valleys (MDV) harbor aquatic ecosystems dominated by the microbial loop. Within this habitat, which is limited year-round by light and nutrients, protists, or single celled eukaryotes, play outsized roles in the food web as the dominant primary producers and the apex predators. Thus, the MDV lake ecosystem represents an ideal system to study the role of sentinel protist taxa in carbon and nutrient cycling. The perennially ice-covered lakes are part of the McMurdo Long Term Ecological Research (McM LTER; mcmlter.org) established in 1993. In this review we will highlight the diversity and trophic roles of the MDV lake protist community and compare environmental factors driving spatiotemporal patterns in key protist taxa in two lakes within the McM LTER, Lakes Bonney and Fryxell. We will then discuss lessons learned from manipulated experiments on the impact of current and future climate-driven environmental change on sensitive protist taxa. Last, we will integrate knowledge gained from 25 years of lab-controlled experiments on key photosynthetic protists to extend our understanding of the function of these extremophiles within the MDV aquatic food webs. Our research group has studied the distribution and function of the MDV microbial community for nearly two decades, training the next generation of scientists to tackle future problems of these globally significant microbes. This review article will also highlight early career scientists who have contributed to this body of work and represent the future of scientific understanding in the Anthropocene.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Kalra, Isha</style></author><author><style face="normal" font="default" size="100%">Wang, Xin</style></author><author><style face="normal" font="default" size="100%">Zhang, Ru</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">High salt-induced PSI-supercomplex is associated with high CEF and attenuation of state transitions</style></title><secondary-title><style face="normal" font="default" size="100%">Photosynthesis Research</style></secondary-title><short-title><style face="normal" font="default" size="100%">Photosynth Res</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">acclimation</style></keyword><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">Chlamydomonas</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclic electron flow</style></keyword><keyword><style  face="normal" font="default" size="100%">PSI-supercomplex</style></keyword><keyword><style  face="normal" font="default" size="100%">salinity</style></keyword><keyword><style  face="normal" font="default" size="100%">state transitions</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2023</style></year><pub-dates><date><style  face="normal" font="default" size="100%">09/2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://link.springer.com/10.1007/s11120-023-01032-y</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">157</style></volume><pages><style face="normal" font="default" size="100%">65 - 84</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;While PSI-driven cyclic electron flow (CEF) and assembly of thylakoid supercomplexes have been described in model organisms like &lt;i&gt;Chlamydomonas reinhardtii&lt;/i&gt;, open questions remain regarding their contributions to survival under long-term stress. The Antarctic halophyte, &lt;i&gt;C. priscuii UWO241&lt;/i&gt; (UWO241), possesses constitutive high CEF rates and a stable PSI-supercomplex as a consequence of adaptation to permanent low temperatures and high salinity. To understand whether CEF represents a broader acclimation strategy to short- and long-term stress, we compared high salt acclimation between the halotolerant UWO241, the salt-sensitive model, &lt;i&gt;C. reinhardtii&lt;/i&gt;, and a moderately halotolerant Antarctic green alga, &lt;i&gt;C.&lt;/i&gt; sp. ICE-MDV (ICE-MDV). CEF was activated under high salt and associated with increased non-photochemical quenching in all three &lt;i&gt;Chlamydomonas&lt;/i&gt; species. Furthermore, high salt-acclimated cells of either strain formed a PSI-supercomplex, while state transition capacity was attenuated. How the CEF-associated PSI-supercomplex interferes with state transition response is not yet known. We present a model for interaction between PSI-supercomplex formation, state transitions, and the important role of CEF for survival during long-term exposure to high salt.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Stahl-Rommel, Sarah</style></author><author><style face="normal" font="default" size="100%">Kalra, Isha</style></author><author><style face="normal" font="default" size="100%">D'Silva, Susanna</style></author><author><style face="normal" font="default" size="100%">Hahn, Mark M.</style></author><author><style face="normal" font="default" size="100%">Popson, Devon</style></author><author><style face="normal" font="default" size="100%">Cvetkovska, Marina</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Cyclic electron flow (CEF) and ascorbate pathway activity provide constitutive photoprotection for the photopsychrophile, &lt;i&gt;Chlamydomonas&lt;/i&gt; sp. UWO 241 (renamed &lt;i&gt;Chlamydomonas priscuii&lt;/i&gt;)</style></title><secondary-title><style face="normal" font="default" size="100%">Photosynthesis Research</style></secondary-title><short-title><style face="normal" font="default" size="100%">Photosynth Res</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">ascorbate</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclic electron flow</style></keyword><keyword><style  face="normal" font="default" size="100%">Photosystem I</style></keyword><keyword><style  face="normal" font="default" size="100%">Psychrophile</style></keyword><keyword><style  face="normal" font="default" size="100%">ROS</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">03/2022</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://link.springer.com/article/10.1007/s11120-021-00877-5</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">151</style></volume><pages><style face="normal" font="default" size="100%">235 - 250</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Under environmental stress, plants and algae employ a variety of strategies to protect the photosynthetic apparatus and maintain photostasis. To date, most studies on stress acclimation have focused on model organisms which possess limited to no tolerance to stressful extremes. We studied the ability of the Antarctic alga &lt;i&gt;Chlamydomonas&lt;/i&gt; sp. UWO 241 (UWO 241) to acclimate to low temperature, high salinity or high light. UWO 241 maintained robust growth and photosynthetic activity at levels of temperature (2 &amp;deg;C) and salinity (700 mM NaCl) which were nonpermissive for a mesophilic sister species, &lt;i&gt;Chlamydomonas raudensis&lt;/i&gt; SAG 49.72 (SAG 49.72). Acclimation in the mesophile involved classic mechanisms, including downregulation of light harvesting and shifts in excitation energy between photosystem I and II. In contrast, UWO 241 exhibited high rates of PSI-driven cyclic electron flow (CEF) and a larger capacity for nonphotochemical quenching (NPQ). Furthermore, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase and maintained a large ascorbate pool. These results matched the ability of the psychrophile to maintain low ROS under short-term photoinhibition conditions. We conclude that tight control over photostasis and ROS levels are essential for photosynthetic life to flourish in a native habitat of permanent photooxidative stress. We propose to rename this organism &lt;i&gt;Chlamydomonas priscuii&lt;/i&gt;.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Raymond, James A.</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author><author><style face="normal" font="default" size="100%">Stahl-Rommel, Sarah</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Glycerol is an osmoprotectant in two Antarctic &lt;I&gt;Chlamydomonas&lt;/I&gt; species from an ice-covered saline lake and is synthesized by an unusual bidomain enzyme</style></title><secondary-title><style face="normal" font="default" size="100%">Frontiers in Plant Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">Chlamydomonas</style></keyword><keyword><style  face="normal" font="default" size="100%">glycerol synthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">glycerol-3-phosphate dehydrogenase</style></keyword><keyword><style  face="normal" font="default" size="100%">Lake Bonney</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphoserine phosphatase</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2020</style></year><pub-dates><date><style  face="normal" font="default" size="100%">08/2020</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.frontiersin.org/articles/10.3389/fpls.2020.01259/full</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">11</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Glycerol, a compatible solute, has previously been found to act as an osmoprotectant in some marine &lt;em&gt;Chlamydomonas&lt;/em&gt; species and several species of &lt;em&gt;Dunaliella&lt;/em&gt; from hypersaline ponds. Recently, &lt;em&gt;Chlamydomonas reinhardtii&lt;/em&gt; and &lt;em&gt;Dunaliella salina&lt;/em&gt; were shown to make glycerol with an unusual bidomain enzyme, which appears to be unique to algae, that contains a phosphoserine phosphatase and glycerol-3-phosphate dehydrogenase. Here we report that two psychrophilic species of &lt;em&gt;Chlamydomonas&lt;/em&gt; (&lt;em&gt;C.&lt;/em&gt; spp. UWO241 and ICE-MDV) from Lake Bonney, Antarctica also produce high levels of glycerol to survive in the lake&amp;rsquo;s saline waters. Glycerol concentration increased linearly with salinity and at 1.3 M NaCl, exceeded 400 mM in &lt;em&gt;C.&lt;/em&gt; sp. UWO241, the more salt-tolerant strain. We also show that both species expressed several isoforms of the bidomain enzyme. An analysis of one of the isoforms of &lt;em&gt;C.&lt;/em&gt; sp. UWO241 showed that it was strongly upregulated by NaCl and is thus the likely source of glycerol. These results reveal another adaptation of the Lake Bonney &lt;em&gt;Chlamydomonas&lt;/em&gt; species that allow them to survive in an extreme polar environment.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Cook, Greg</style></author><author><style face="normal" font="default" size="100%">Teufel, Amber</style></author><author><style face="normal" font="default" size="100%">Kalra, Isha</style></author><author><style face="normal" font="default" size="100%">Li, Wei</style></author><author><style face="normal" font="default" size="100%">Wang, Xin</style></author><author><style face="normal" font="default" size="100%">John C. Priscu</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The Antarctic psychrophiles &lt;i&gt;Chlamydomonas&lt;/i&gt; spp. UWO241 and ICE-MDV exhibit differential restructuring of photosystem I in response to iron</style></title><secondary-title><style face="normal" font="default" size="100%">Photosynthesis Research</style></secondary-title><short-title><style face="normal" font="default" size="100%">Photosynth Res</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclic electron flow</style></keyword><keyword><style  face="normal" font="default" size="100%">Iron</style></keyword><keyword><style  face="normal" font="default" size="100%">Photosystem I</style></keyword><keyword><style  face="normal" font="default" size="100%">Psychrophile</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2019</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://link.springer.com/article/10.1007/s11120-019-00621-0</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">9</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;em&gt;Chlamydomonas &lt;/em&gt;sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that &lt;em&gt;C&lt;/em&gt;. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of &lt;em&gt;C&lt;/em&gt;. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in &lt;em&gt;C&lt;/em&gt;. sp. UWO241, a mesophile, C. &lt;em&gt;reinhardtii&lt;/em&gt; SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, &lt;em&gt;Chlamydomonas&lt;/em&gt; sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA&lt;sub&gt;820&lt;/sub&gt;/A&lt;sub&gt;820&lt;/sub&gt;) were reduced in both psychrophiles relative to the mesophile. Upon increasing Fe, &lt;em&gt;C&lt;/em&gt;. sp. ICE-MDV and C. &lt;em&gt;reinhardtii&lt;/em&gt; exhibited restoration of PSI function, while &lt;em&gt;C&lt;/em&gt;. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 μM Fe&lt;sup&gt;2+&lt;/sup&gt;), &lt;em&gt;C&lt;/em&gt;. sp. UWO241 grown in 18 μM Fe&lt;sup&gt;2+&lt;/sup&gt; exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile &lt;em&gt;C&lt;/em&gt;. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photo-chemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Teufel, Amber G.</style></author><author><style face="normal" font="default" size="100%">Rachael M. Morgan-Kiss</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Influence of abiotic drivers (light and nutrients) on photobiology and diversity of Antarctic lake phytoplankton communities</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Microbiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctica</style></keyword><keyword><style  face="normal" font="default" size="100%">bacterial production</style></keyword><keyword><style  face="normal" font="default" size="100%">Chlamydomonas sp ICE MDV</style></keyword><keyword><style  face="normal" font="default" size="100%">Chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">circadian rhythm</style></keyword><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">McMurdo Dry Valleys</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient amendment</style></keyword><keyword><style  face="normal" font="default" size="100%">photobiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Primary production</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2016</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2016</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://rave.ohiolink.edu/etdc/view?acc_num=miami1468411564</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Miami University</style></publisher><pub-location><style face="normal" font="default" size="100%">Oxford, OH</style></pub-location><volume><style face="normal" font="default" size="100%">Ph.D.</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Arctic, Antarctic, and alpine ecosystems are recognized as sensors and sentinels of global climate change. As a consequence of their high sensitivity to minor climatic perturbations, permanently ice-covered lakes located in the McMurdo Dry Valleys (MCM), Antarctica, represent end members in the global network of inland bodies of water. Episodic climatic events in the form of increased summer glacial melt result in inputs of organic sediment and nutrients from glacial streams to these closed basins. By better understanding how Antarctic lake communities respond to mimicked climate change, we can more accurately predict how they will react to further temperature changes in the future. We began by investigating the influence of inorganic nitrogen and phosphorus availability on planktonic communities residing in the oligotrophic upper waters of two chemically distinct MCM lakes (Lakes Bonney and Fryxell) which differ in their external inputs as well as water column N:P stoichiometry. Although microbial community responses varied between the lakes and were nutrient-dependent, stimulation of phytoplankton biomass and productivity across all treatments was strongly linked with increased abundance of a single phytoplankton phylum (Chlorophyta). Despite stimulation of phytoplankton growth, primary and bacterial productivity were largely uncoupled across all enrichments. We suggest that climate-associated shifts in phytoplankton diversity influence the bacterial community structure by altering the availability and composition of autochthonous carbon for heterotrophic production. To monitor the physiological adaptations that occur over time and depth, we then transplanted two dominant phytoplankton, &lt;em&gt;Chlamydomonas&lt;/em&gt; sp. ICE- MDV and &lt;em&gt;Isochrysis&lt;/em&gt; sp. MDV back into the Lake Bonney water column. Our results demonstrated that both organisms are specialists for surviving specific depths of the water column and are capable of acclimating to their native environment within a short period of time, and that the chlorophyte &lt;em&gt;Chlamydomonas&lt;/em&gt; sp. ICE-MDV most likely makes this adjustment via photoacclimation and accumulating chlorophyll-a per cell. The final study presented here investigated whether or not the dominant chlorophyte, &lt;em&gt;Chlamydomonas&lt;/em&gt; sp. ICE-MDV has retained the ability to respond to a diel 12-hour day/night cycle. Although light levels in MCM lakes remain low during the austral summers, daily irradiation varies by as much as tenfold during the course of the day, resulting in a circadian-like light cycle for organisms residing there. With decreased ice coverage on the lakes due to climate change and increased melt, it is likely that these light variations will become amplified over time. This study tested for the presence of a circadian rhythm under various light quality, light quantity, and temperature conditions and demonstrated that although a diel rhythm was maintained in terms of growth and several photochemical parameters, a true circadian rhythm was not identified. Although it is predicted that photosynthetic communities in polar regions will be more responsive to climate warming and episodic events, the complexity of these systems provides numerous challenges to understanding how these organism will adapt in the future.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">doctoral</style></work-type></record></records></xml>