The soils of the Maritime and sub-Antarctic experience extreme environmental conditions but nonetheless host biological communities that can survive low temperatures, limited water availability and short day lengths or even the complete absence of solar radiation during the winter. We determined the soil organic carbon (SOC) and total nitrogen (N), soil microbial biomass (SMB), labile carbon (LC) and respiration rate (RR) in soil samples from the longest latitudinal transect (approximately 2,000 km) ever sampled exclusively in the Maritime and sub-Antarctic, comprising 69 sites located between South Georgia (54°S) and south-eastern Alexander Island (72°S). With the exception of the most northerly location (South Georgia), the greatest SMB values occurred at 67–68°S, despite the harsh environmental conditions. This is consistent with the relative nutrient richness of the soils at these latitudes, as indicated by large SOC and total soil N concentrations, which are in turn probably linked to more abundant guano and excreta deposition by sea birds and seals, which have fewer and smaller areas of ice-free terrain to land or haul out on further south. South of 68°S, SOC values declined with increasing latitude, which is probably due to increasingly extreme environmental conditions. We also found that the SOC and SMB values, the proportion of SOC considered labile (LC/SOC) and the carbon mineralization rates expressed as either RR/SOC or RR/SMB were all small compared with values from less extreme temperate and tropical regions. However, the proportion of the SOC in the microbial biomass (SMB/SOC) was substantially greater than that reported for non-polar soils. We conclude that although the soils of the Maritime and sub-Antarctic have small and relatively inactive microbial communities, they are characterized by efficient conversion of organic resources into microbial biomass and large affinities for added substrates. Highlights: Soil carbon parameters are reported from sites along the longest latitudinal transect in Antarctica ever sampled. The soil microbial biomass tended to peak at 67–68°S, coinciding with relative SOC and N abundance in the soil, probably arising from guano and excreta from sea birds and mammals. The soil microbial community was small but highly efficient at converting organic resources into microbial biomass, as indicated by large microbial biomass/soil organic carbon ratios.

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精益和敏锐：南极海洋土壤中的微生物活动

海洋和亚南极地区的土壤经历了极端的环境条件，但仍然承载着生物群落，它们可以在低温、有限的可用水量和较短的白天，甚至在冬季完全没有太阳辐射的情况下生存。我们测定了有史以来最长的横断面（约 2,000 公里）的土壤样品中的土壤有机碳 (SOC) 和总氮 (N)、土壤微生物生物量 (SMB)、不稳定碳 (LC) 和呼吸率 (RR)在海洋和亚南极地区，包括位于南乔治亚岛 (54°S) 和亚历山大岛东南部 (72°S) 之间的 69 个站点。除了最北的位置（南乔治亚州），尽管环境条件恶劣，但最大的 SMB 值发生在 67-68°S。这与这些纬度土壤的相对营养丰富度一致，如大 SOC 和土壤总氮浓度所示，这反过来可能与海鸟和海豹更丰富的鸟粪和排泄物沉积有关，海鸟和海豹的粪便越来越少无冰地形的地区登陆或拖到更南的地方。在 68°S 以南，SOC 值随着纬度的增加而下降，这可能是由于环境条件越来越极端。我们还发现，与来自不太极端的温带和热带地区的值相比，SOC 和 SMB 值、被认为不稳定的 SOC 比例 (LC/SOC) 和以 RR/SOC 或 RR/SMB 表示的碳矿化率都较小。然而，微生物生物量 (SMB/SOC) 中 SOC 的比例大大高于非极性土壤中报道的比例。我们得出的结论是，虽然海洋和亚南极地区的土壤具有较小且相对不活跃的微生物群落，但它们的特点是有机资源有效转化为微生物生物量，并且对添加的底物有很大的亲和力。亮点：从南极洲有史以来采样的最长纬度横断面沿线的地点报告了土壤碳参数。土壤微生物生物量趋于在 67-68°S 达到峰值，与土壤中的相对 SOC 和 N 丰度一致，可能来自海鸟和哺乳动物的鸟粪和排泄物。土壤微生物群落虽小，但能高效地将有机资源转化为微生物生物量，