Late Holocene precipitation record from Windmill Island lakes

Antarctic lake cores record a history of precipitation in the preservation of climate sensitive microbial communities. Comprehensive integration of our precipitation records with other climate proxies such as ice core temperature records and historical climate data are dependent upon accurate dating of this lake sediment.Fourteen lakes and ponds of the Windmill Islands were sampled in 1998 for diatoms and in 1999 for water chemistry. The waterbodies included in this study fall into one of 3 broad categories: saline lake (greater than 5m deep; greater than, or equal to, 3 parts per thousand - salinity), saline pond (less than 5m deep; greater than, or equal to, 3 parts per thousand - salinity) or freshwater pond (less than 5m deep; less than 3 parts per thousand - salinity). Saline LakesBeall Lake, the largest lake on Beall Island, is situated in a rocky catchment with evidence of breeding penguin pairs nearby. Outflow into the small lake on the northwestern point of Beall Lake occurs at elevated lake levels. Holl Lake, the largest lake on Holl Island, is contained by ridges to the NE and SW with an obvious outflow to the SE. At the time of sampling (20 Dec 1998), penguin feathers were observed in the sediment. In 2001 large numbers of penguins were observed behind the NE ridge in addition to the numerous skuas nesting on most nearby peaks.Lake A is the westernmost lake on Browning Peninsula. This large closed saline lake has a very thick ice cover (~2.5 m) and very little evidence of birdlife.Lake M is the easternmost lake sampled on Browning Peninsula. This large closed saline lake had a very thick ice cover (3.0 m) at the time of sampling.Saline PondsLake Warrington is the largest waterbody on Warrington Island. Found in the centre of Warrington Island, this small shallow (1.9 m) saline pond was almost completely frozen (ice cover of 1.6 m), with ca. 0.3 m of water below the ice at the time of sampling. The lake catchment is muddy with runoff towards Robertson Channel (to the NE) and the ice cover showed signs of sediment entrapment giving a gritty texture.Lake G is located on northeastern Peterson Island. This very saline (greater than 60 ppt) shallow (1.0 m) pond was almost completely frozen (ice cover of 0.8 m), with ca. 0.1 m of water below the ice at the time of sampling. Lake G is close to breeding penguin sites and there was a noticeable discolouration of the surface water at the time of sampling.Lake I is the easternmost of the three sites visited on southern Peterson Island. This shallow (0.3 m) saline pond is very close to breeding penguin sites and was sampled by hand as the ice cover (0.1 m) was almost as thick as the lake depth.Lake K is approx. 400 m to the west of Lake I on central southern Peterson Island. This completely frozen saline pond is also very close to breeding penguin sites.Lake L is the southernmost pond sampled on Peterson Island. This almost completely frozen shallow (~0.8 m/0.8 m ice cover) saline pond is very close to breeding penguin sites with noticeable discolouration of the top ca. 0.2 - 0.3 m of water at the time of sampling.Freshwater PondsLake B, a shallow (0.9 m) freshwater pond, is located on the western side of Browning Peninsula, approx. 500 m to the south of Lake A.Lake C is a shallow (1.0 m) freshwater pond in the central valley of Browning Peninsula.Lake D is a shallow (0.5 m) freshwater pond in the central valley of Browning Peninsula approx. 500 m to the north of Lake C. This lake was sampled by hand as the ice cover (~0.5 m) was almost as thick as the lake depth.Lake E is a shallow (3.1 m) freshwater pond in the central valley of Browning Peninsula approx. 250 m to the north of Lake D.Lake F is the northernmost pond sampled from the central valley of Browning Peninsula. This freshwater pond is approx. 500 m to the north-west of Lake E.The sediment/species samples were collected in November and December 1998, the water samples were collected in December 1999.The fields in this dataset are:Lake NameCodeLocationLatitudeLongitudeLake DepthIce DepthWater SampleSalinityLake AreaCatchmentElevationNitriteNitrateSiliconPhosphatepHSpeciesThe numbers given in the species spreadsheet are for percentage abundance, ie the relative abundance of each species in the community.南极湖芯记录了气候敏感型微生物群落所保存的降水历史。将本研究的降水记录与冰芯温度记录、历史气候数据等其他气候代用指标进行综合集成，有赖于对该湖泊沉积物的精准定年。1998年，研究团队对风车群岛的14个湖泊与池塘开展了硅藻采样；1999年则针对这些水体开展了水化学采样。本研究涉及的水体可划分为三大类：咸水湖（水深＞5m，盐度≥3‰）、咸水池塘（水深＜5m，盐度≥3‰）以及淡水池塘（水深＜5m，盐度＜3‰）。 咸水湖：比尔湖（Beall Lake）是比尔岛上最大的湖泊，坐落于多岩集水区内，周边存在企鹅繁殖种群的活动痕迹。当湖泊水位升高时，湖水会注入比尔湖西北岸的小型湖泊。霍尔湖（Holl Lake）是霍尔岛上最大的湖泊，被东北、西南两侧的山脊环绕，存在明显的东南向出水通道。1998年12月20日采样期间，沉积物中发现了企鹅羽毛。2001年，除多数邻近山峰上筑巢的大量贼鸥外，东北山脊后方还观测到了大规模的企鹅种群。A湖是布朗宁半岛最西侧的湖泊，为大型封闭型咸水湖，冰盖厚度约2.5m，几乎无鸟类活动痕迹。M湖是布朗宁半岛采样的最东侧湖泊，为大型封闭型咸水湖，采样时冰盖厚度达3.0m。 咸水池塘：沃灵顿池塘（Lake Warrington）是沃灵顿岛上最大的水体，坐落于该岛中部，为小型浅水环境（水深1.9m）。采样期间该池塘几乎完全封冻，冰盖厚度1.6m，冰下水深约0.3m。其集水区为泥质，径流朝向东北方向的罗伯逊海峡，冰盖存在沉积物截留痕迹，质地粗糙。G湖位于彼得森岛东北部，为盐度＞60ppt的浅水环境（水深1.0m），采样期间几乎完全封冻，冰盖厚度0.8m，冰下水深约0.1m。G湖邻近企鹅繁殖地，采样时表层水体存在明显变色现象。I湖是彼得森岛南部三个采样点中最东侧的一个，为浅水环境（水深0.3m），紧邻企鹅繁殖地。因冰盖厚度（0.1m）几乎与湖深相当，研究团队采用人工方式完成采样。K湖位于彼得森岛中南部，距I湖西侧约400m，为完全封冻的咸水池塘，同样紧邻企鹅繁殖地。L湖是彼得森岛采样的最南侧池塘，为近乎完全封冻的浅水环境（水深约0.8m，冰盖厚0.8m），紧邻企鹅繁殖地。采样期间，表层约0.2~0.3m的水体存在明显变色。 淡水池塘：B湖为水深0.9m的淡水池塘，位于布朗宁半岛西侧，距A湖南侧约500m。C湖为水深1.0m的淡水池塘，坐落于布朗宁半岛中部山谷。D湖为水深0.5m的淡水池塘，位于布朗宁半岛中部山谷，距C湖北侧约500m。因冰盖厚度（约0.5m）几乎与湖深相当，研究团队采用人工方式完成采样。E湖为水深3.1m的淡水池塘，位于布朗宁半岛中部山谷，距D湖北侧约250m。F湖是布朗宁半岛中部山谷采样的最北侧淡水池塘，距E湖西北侧约500m。 沉积物/生物样品采集于1998年11月至12月，水样采集于1999年12月。本数据集包含以下字段：湖泊名称、编号、地理位置、纬度、经度、湖泊水深、冰盖厚度、水样采集情况、盐度、湖泊面积、集水区、海拔、亚硝酸盐、硝酸盐、硅酸盐、磷酸盐、pH值、物种组成。物种统计表中的数值为相对丰度百分比，即群落中各物种的相对占比。