Fungi are ubiquitous in the marine en vironment, but their role in carbon and nitrogen cycling in the ocean, and in particular the quantitative significance of fungal biomass to ocean biogeochemistry, has not yet been assessed. Determination of the biochemical and stable isotope composition of marine fungi can provide a basis for identifying fungal patterns in relation to other microbes and detritus, and thus allow evaluation of their contribution to the transformation of marine organic matter. We characterized the biochemical composition of 13 fungal strains isolated from distinct marine environments in the eastern South Pacific Ocean off Chile. Proteins accounted for 3 to 21% of mycelial dry weight, with notably high levels of the essential amino acids histidine, threonine, valine, lysine and leucine, as well as polyunsaturated fatty acids, ergo sterol, and phosphatidylcholine. Elemental composition and energetic content of these marine-derived fungi were within the range reported for bacteria, phytoplankton, zooplankton and other metazoans from aquatic environments, but a distinct pattern of lipids and proteins was identified in marine planktonic fungi. These biochemical signatures, and an elemental composition indicative of a marine planktonic source, have potential applications for the assessment of fungal contribution to marine microbial biomass and organic matter reservoirs, and the cycling of carbon and nutrients.

中文翻译：

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海洋真菌的生化指纹：对营养和生物地球化学研究的意义

真菌在海洋环境中无处不在，但它们在海洋中碳和氮循环中的作用，特别是真菌生物量对海洋生物地球化学的定量意义尚未得到评估。确定海洋真菌的生化和稳定同位素组成可以为识别与其他微生物和碎屑相关的真菌模式提供基础，从而评估它们对海洋有机物转化的贡献。我们表征了从智利附近南太平洋东部不同海洋环境中分离出来的 13 种真​​菌菌株的生化成分。蛋白质占菌丝体干重的 3% 至 21%，其中必需氨基酸组氨酸、苏氨酸、缬氨酸、赖氨酸和亮氨酸以及多不饱和脂肪酸含量特别高，麦角甾醇和磷脂酰胆碱。这些海洋衍生真菌的元素组成和能量含量在细菌、浮游植物、浮游动物和其他水生环境后生动物的报告范围内，但在海洋浮游真菌中发现了一种独特的脂质和蛋白质模式。这些生化特征以及指示海洋浮游生物来源的元素组成，在评估真菌对海洋微生物生物量和有机物质库的贡献以及碳和养分循环方面具有潜在的应用价值。但是在海洋浮游真菌中发现了一种独特的脂质和蛋白质模式。这些生化特征以及指示海洋浮游生物来源的元素组成，在评估真菌对海洋微生物生物量和有机物质库的贡献以及碳和养分循环方面具有潜在的应用价值。但是在海洋浮游真菌中发现了一种独特的脂质和蛋白质模式。这些生化特征以及指示海洋浮游生物来源的元素组成，在评估真菌对海洋微生物生物量和有机物质库的贡献以及碳和养分循环方面具有潜在的应用价值。