Functional dynamics of the microbial loop in saline lakes of the Vestfold Hills

Metadata record for data expected from ASAC Project 919.See the link below for public details on this project.The plankton dynamics of Ace Lake, a saline, meromictic basin in the Vestfold Hills, eastern Antarctica was studied between December 1995 and February 1997. The lake supported two distinct plankton communities; an aerobic microbial community in the upper oxygenated mixolimnion and an anaerobic microbial community in the lower anoxic monimolimnion. Phytoplankton development was limited by nitrogen availability. Soluble reactive phosphorus was never limiting. Chlorophyll a concentrations in the mixolimnion ranged between 0.3 and 4.4 micrograms per litre during the study period and a deep chlorophyll maximum persisted throughout the year below the chemo/oxycline. Bacterioplankton abundance showed considerable seasonal variation related to light and substrate availability. Autotrophic bacterial abundance ranged between 0.02 and 8.94 x 10 to the 8 per litre and heterotrophic bacterial abundance between 1.26 and 72.8 x 10 to the 8 per litre throughout the water column. the mixolimnion phtyoplankton was dominated by phytoflagellates, in particular Pyramimonas gledicola. P. geldicola remained active for most of the year by virtue of its mixotrophic behaviour. Photosynthetic dinoflagellates occurred during the austral summer, but the entire population encysted for the winter. Two communities of heterotrophic flagellates were apparent; a community living in the upper monimolimnion and a community living in the aerobic mixolimnion. Both exhibited different seasonal dynamics. The cliliate community was dominated by the autotroph Mesodinium rubrum. The abundance of M. rubrum peaked in summer. A proportion of the population encysted during winter. Only one other ciliate, Euplotes sp., occurred regularly. Two species of Metazoa occurred in the mixolimnion; a calanoid copepod (Paralabidocera antarctica) and a rotifer (Notholca sp.). However, there was no evidence of grazing pressure on the microbial community. In common with most other Antarctic lakes, Ace Lake appears to be driven by 'bottom-up' forces.The fields in this dataset are:Ace LakeAerobic monimolimnionAmmoniaAmmoniumAsh free dry weightAutotrophic BacteriaBacterial Production LeucineBacterial Production ThymidineBiomassCarbonCellChlorophyll aConcentrationCopepodsDateDate CodeDepthDiatomsDinoflagellatesDissolved Organic CarbonDissolved OxygenDoublingGeneration TimeHeterotrophic BacteriaHeterotrophic NanoflagellatesIce ThicknessIntrinsic Growth RateJulian DayJulian MonthMesodinium rubrumMesodinium rubrum cystsMixolimnionMonimolimnionNaupliiNitrateNitriteNotholca sp.Other CiliatesOxygenated strataParalabidocera antarctica copepodidParalabidocera antarctica naupliarParticulate Organic CarbonPhosphatePhototrophic NanoflagellatesSalinitySeasonSoluble Reactive PhosphorusTotal CiliatesWater Temperature

本数据集为ASAC第919项目预期产出的数据元记录。有关该项目的公开详情，请参阅下方链接。1995年12月至1997年2月期间，研究团队对位于南极东部弗德霍夫丘陵（Vestfold Hills）的盐性永分层湖盆（meromictic basin）艾斯湖（Ace Lake）的浮游生物动力学展开了研究。该湖泊存在两套截然不同的浮游生物群落：上层含氧混合层（mixolimnion）中的需氧微生物群落，以及下层缺氧下层滞水带（monimolimnion）中的厌氧微生物群落。浮游植物的生长受氮素可利用性限制，而可溶性活性磷（Soluble Reactive Phosphorus）始终未成为限制因子。研究期内，混合层中的叶绿素a（Chlorophyll a）浓度介于0.3至4.4微克每升之间，且化学氧跃层（chemo/oxycline）下方全年存在一处深层叶绿素最大值层。浮游细菌丰度随季节出现显著波动，其变化与光照及底物可利用性相关。整个水柱中，自养细菌（Autotrophic Bacteria）丰度范围为0.02×10^8至8.94×10^8个每升，异养细菌（Heterotrophic Bacteria）丰度范围为1.26×10^8至72.8×10^8个每升。混合层的浮游植物以植鞭毛虫占优，尤以Pyramimonas gledicola为甚，该物种凭借混合营养型代谢策略，全年大部分时间均可保持活性。光合型甲藻（Dinoflagellates）仅在南极夏季出现，冬季时整个种群均形成孢囊休眠。异养鞭毛虫存在两个明显的群落类群：一类栖息于下层滞水带，另一类栖息于上层需氧混合层，二者的季节动态特征各不相同。纤毛虫群落以自养型Mesodinium rubrum为优势类群，其丰度在夏季达到峰值，冬季时部分种群会形成孢囊；仅有另一种纤毛虫Euplotes sp.为常见类群。混合层中还存在两类后生动物：一类是哲水蚤目桡足类Paralabidocera antarctica，另一类是轮虫Notholca sp.。但未发现该类群对微生物群落存在牧食压力。与多数南极湖泊类似，艾斯湖的生态系统似乎受上行效应（bottom-up forces）驱动。本数据集包含以下字段：艾斯湖（Ace Lake）、需氧下层滞水带（Aerobic monimolimnion）、氨（Ammonia）、铵（Ammonium）、灰分干重（Ash free dry weight）、自养细菌（Autotrophic Bacteria）、亮氨酸法细菌生产力（Bacterial Production Leucine）、胸腺嘧啶法细菌生产力（Bacterial Production Thymidine）、生物量（Biomass）、碳（Carbon）、细胞（Cell）、叶绿素a（Chlorophyll a）、浓度（Concentration）、桡足类（Copepods）、日期（Date）、日期编码（Date Code）、深度（Depth）、硅藻（Diatoms）、甲藻（Dinoflagellates）、溶解有机碳（Dissolved Organic Carbon）、溶解氧（Dissolved Oxygen）、倍增世代时间（Doubling Generation Time）、异养细菌（Heterotrophic Bacteria）、异养纳米鞭毛虫（Heterotrophic Nanoflagellates）、冰厚（Ice Thickness）、内在生长率（Intrinsic Growth Rate）、儒略日（Julian Day）、儒略月（Julian Month）、红色中缢虫（Mesodinium rubrum）、红色中缢虫孢囊（Mesodinium rubrum cysts）、混合层（Mixolimnion）、下层滞水带（Monimolimnion）、无节幼体（Nauplii）、硝酸盐（Nitrate）、亚硝酸盐（Nitrite）、Notholca属未定种（Notholca sp.）、其他纤毛虫（Other Ciliates）、含氧水层（Oxygenated strata）、南极拟拉比达桡足类幼体（Paralabidocera antarctica copepodid）、南极拟拉比达桡足类无节幼体（Paralabidocera antarctica naupliar）、颗粒有机碳（Particulate Organic Carbon）、磷酸盐（Phosphate）、光合型纳米鞭毛虫（Phototrophic Nanoflagellates）、盐度（Salinity）、季节（Season）、可溶性活性磷（Soluble Reactive Phosphorus）、总纤毛虫丰度（Total Ciliates）、水温（Water Temperature）