Diane M. McKnight 2014-11-04 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/e9d17c42840bc30988a18d14b3e4d3a7 https://mcm.lternet.edu/content/summer-vs-winter-phytoplankton-presence-1989-1991 Using automated overwinter sampling devices, we collected preserved phytoplankton samples from multiple depths in Lake Fryxell, a permanently ice-covered lake in southern Victoria Land, Antarctica. Photosynthetic algae were maintained in a stable water column throughout winter darkness. The algal taxa overwintered in different ways in a species-specific manner. Typical vegetative cells were the most abundant form for all species found in the water column. Populations of one chlorophyte, Stichococcus sp., were observed in winter, but the species was absent in both summers. Two cryptophyte species were more abundant in winter than in summer. We interpret the increase in algal population size as evidence of heterotrophic growth in winter and of mixotrophic behavior throughout the year. For two chlorophyte species, some portion of the population had a distinctive morphology, for example, many Chlamydomonas subcaudata Wille. formed akinetes, whereas many Chlorella sp. contained a large amount of starch or other storage material. During winter, vegetative cells of the most abundant cyanobacterial species, Phormidium angustissimum West et West, occurred at the depth of the summer maximum and at depths below the oxycline. The presence of P. angustissimum below the oxycline may have resulted from the accumulation of settling cells at a depth with a greater density. In contrast to the settling of P. angustissimum, the general absence of the other algal species below the oxycline in winter indicated that these species were not influenced by overwinter settling. Data contained in these files has been subjected to quality control standards imposed by the investigator. The user of this data should be aware that, while efforts have been taken to ensure that these data are of the highest quality, there is no guarantee of perfection for the data contained herein and the possibility of errors exists. If you encounter questionable data, please contact the MCM LTER data manager corrected or qualified. Thus, these data may be modified and future data will be appended. 1989-01-01 1991-12-31 ground condition In 2015, Inigo San Gil renamed the data-source to LIMNO_PHYTO_PRESENCE_SUM_WIN (formerly was phytprsn) to make it coherent with the database stored data. At the same time, some enhancements to the variables definitions were introduced. Data and metadata were migrated to DEIMS. As needed The Lake Fryxell basin is formed by a moraine depression in a wider portion of the Taylor Valley. It has a number of moraine islands and shallower areas, as well as several relatively well developed deltas. The lake is fed by at least 10 meltwater streams with a total drainage catchment of 230 km2. The lake is dammed to the southwest by the Canada Glacier and is topographically closed. It is perennially ice covered; during summer months, an ice-free moat generally forms around much of the lake margin. Lake levels have risen ~2 m between 1971 and 1996. There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 9 Maximum Length (km): 5.8 Maximum Width (km): 2.1 Maximum Depth (m): 20 Surface Area (km^2): 7.08 Ice Thickness Average Surface (m): 3.3 - 4.5 Volume (m^3 * 10^6): 25.2 163.259582519531 163.048782348633 -77.597076416016 -77.622711181641 18m 18m meter LTER Core Areas population dynamics None <cntorg>McMurdo Dry Valleys LTER</cntorg> <onlink>http://mcmlter.org/</onlink> <span property="dc:title" content="McMurdo Dry Valleys LTER" class="rdf-meta element-hidden"></span> Name: Inigo San Gil Role: data manager Not Applicable Not Applicable Field and/or Lab Methods unknown LIMNO_PHYTO_PRESENCE_SUM_WIN formerly known as phytprsn. Find details here about the measurements metadata - units used, codes, etc. DATASET_CODE Table Identifier The data provider Table Identifier Phylum Phylum for the specimens observed The data provider Bacillariophyta Bacillariophyta The data provider Chlorophyta Chlorophyta The data provider Chrysophyta Chrysophyta The data provider Cyanophyta Cyanophyta The data provider Cryptophyta Cryptophyta The data provider Species Species of the organism The data provider Species of the organism LOCATION NAME The place or location where samples were taken. In this case, it is on Lake Fryxell. The data provider The place or location where samples were taken. In this case, it is on Lake Fryxell. Time Period The time period when the organism presence was monitored The data provider Winter 1989 The austral winter of 1989 The data provider Summer 1990 The austral summer of 1990 The data provider Winter 1990 The austral winter of 1990 The data provider Summer 1991 The austral summer of 1991 The data provider PRESENCE boolean presence, a 0 indicates the organism was not detected at the time period, a 1 indicates the organism presence detected. The data provider FALSE absent The data provider TRUE present The data provider McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 \n 1 column , https://mcm.lternet.edu/sites/default/files/data/LIMNO_PHYTO_PRESENCE_SUM_WIN.csv None 2014-11-04 2014-11-04 McMurdo Dry Valleys LTER http://mcmlter.org/ Biological Data Profile of the Content Standards for Digital Geospatial Metadata devised by the Federal Geographic Data Committee. 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