01464nas a2200181   4500008004100000022001400041245014100055210006900196260001200265520082200277653002101099653002001120653002301140653001801163653001001181100002901191856006201220       2024                        eng d  a0028-646X00aLong days and long nights: An integrative study reveals survival strategies of an Antarctic diatom during the cold and dark polar winter0 aLong days and long nights An integrative study reveals survival   c01/20243 a<p>The vast majority of photosynthetic organisms on Earth have evolved under a circadian cycle, with many cellular processes being regulated by the predictable patterns of day and night. Polar algal species living in Arctic and Antarctic aquatic habitats are faced with bizarre light environments of continuous light during the short summer months and 24-h darkness during the winter, that is one long day transitioning into one long, cold night. It is well known that polar phytoplankton survive the winter and return in the summer to form blooms. In an article recently published in New Phytologist, Joli et al. (2023, doi: 10.1111/nph.19387) use an integrative approach to dissect how an Antarctic marine diatom not only survives the long, dark polar winter, but also recovers rapidly upon the onset of summer.</p>10aaquatic habitats10acircadian cycle10alight environments10aphytoplankton10apolar1 aMorgan-Kiss, Rachael, M.  uhttps://nph.onlinelibrary.wiley.com/doi/10.1111/nph.1953602559nas a2200301   4500008004100000245008000041210006900121260001200190300001200202490000700214520166000221653001501881653001601896653002901912653001801941653001201959100002901971700001802000700002202018700002002040700002202060700001202082700001602094700002602110700002102136700003302157856006702190       2024                        eng d00aSentinel protist taxa of the McMurdo Dry Valley lakes, Antarctica: A review0 aSentinel protist taxa of the McMurdo Dry Valley lakes Antarctica  c03/2024  a13234720 v123 a<p>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.</p>10aAntarctica10aDisturbance10aMcMurdo Dry Valley lakes10aphytoplankton10aprotist1 aMorgan-Kiss, Rachael, M.1 aPopson, Devon1 aPereira, Rochelle1 aDolhi-Binder, J1 aTeufel, Amber, G.1 aLi, Wei1 aKalra, Isha1 aSherwell, Shasten, S.1 aReynebeau, Emily1 aTakacs-Vesbach, Cristina, D.  uhttps://www.frontiersin.org/articles/10.3389/fevo.2024.132347201902nas a2200181   4500008004100000245011100041210006900152260003900221490000900260520124000269653001901509653002401528653002601552653001801578100002601596700002901622856006901651       2020                        eng d00aResponse of microbial communities to climatic disturbances in Lake Bonney, McMurdo Dry Valleys, Antarctica0 aResponse of microbial communities to climatic disturbances in La  aOxford, OHbMiami Universityc20200 vM.S.3 a<p>The McMurdo Dry Valleys is a polar desert ecosystem which composes the largest ice-free area in Antarctica, with the exception of perennially ice-covered lakes and ponds. The lakes in the valleys are the only landscape unit that support metabolic activity year-round. Recent increases in air temperature and solar radiation have led to a chain of disturbances altering the environmental conditions of these lakes. In this study, we test the impact of climatic disturbances on microbial communities in Lake Bonney, one of the lakes in the MDV. Through an integrated approach of combining field studies on natural communities in the lake (in situ) and laboratory experiments on algal isolates (ex situ), this study will attempt to understand how phytoplankton, eukaryal and bacterial communities respond to simulated disturbances. Results from the in situ experiments showed that the moat is a unique and stressful environment for under-ice communities and that under-ice shallow communities are highly sensitive to climatic disturbances. The ex situ experiments showed that certain phytoplankton species, like the chlorophytes, are more resistant to environmental alterations and thus will outcompete other phytoplankton species.</p>10aclimate change10aMcMurdo Dry Valleys10amicrobial communities10aphytoplankton1 aSherwell, Shasten, S.1 aMorgan-Kiss, Rachael, M.  uhttp://rave.ohiolink.edu/etdc/view?acc_num=miami159595868836487702158nas a2200229   4500008004100000245010300041210006900144260003900213490000900252520137700261653001001638653002801648653003801676653002401714653001901738653001801757653002301775653001601798100001601814700002901830856006901859       2019                        eng d00aImpact of simulated polar night on Antarctic mixotrophic and strict photoautotrophic phytoplankton0 aImpact of simulated polar night on Antarctic mixotrophic and str  aOxford, OHbMiami Universityc20180 vM.S.3 a<p>Phytoplankton in polar regions experience long periods of continuous darkness annually during the polar night. Due to difficulties in performing field work during this period, it is largely unknown how phytoplankton endure this extreme transition from 24-hour daylight in the fall to several months of total darkness in the austral winter. The primary goal of this study was to compare physiological and photosynthetic responses of several Antarctic phytoplankton of variable trophic abilities (pure photosynthetic vs. mixotrophic) to simulated polar night conditions, including the transition seasons before and after winter. Two distinct responses were observed to extended darkness: (1) strict photoautotrophs (<em>Chlamydomonas</em> sp. ICE-MDV and <em>Chlamydomonas</em> sp. UWO241) exhibited functional downregulation their photosynthetic processes in the winter, followed by a lag phase of several days during mimicked spring, and (2) mixotrophs (<em>Isochrysis</em> sp. MDV and <em>Geminigera cryophila</em>) maintained functional photosynthetic apparatus, increased heterotrophy through the winter, and exhibited immediate growth upon return to light incubation. These differing responses to mimicked polar night conditions could represent two different strategies for surviving the long period of darkness in the phytoplankton&rsquo;s natural environment.</p>10aalgae10aAntarctic phytoplankton10achlorophyll fluorescence analysis10aMcMurdo Dry Valleys10aPhotosynthesis10aphytoplankton10apolar microbiology10apolar night1 aCariani, ZE1 aMorgan-Kiss, Rachael, M.  uhttp://rave.ohiolink.edu/etdc/view?acc_num=miami1547204599969081