Stable carbon and oxygen isotope composition of calcites associated with modern freshwater cyanobacteria and algae
Stable carbon and oxygen isotope composition of calcites associated with modern freshwater cyanobacteria and algae
复制标题
与现代淡水蓝藻和藻类相关的方解石的稳定碳和氧同位素组成
DOI：
10.1080/01490459009377875
复制
发表时间：
1990
影响因子：
2.3
通讯作者：
B. Spiro
中科院分区：
文献类型：
--
作者：
A. Pentecost;B. Spiro
研究了英国石灰华沉积流中与淡水蓝藻Homoeothrix甲壳类、壳状磷藻（Phormidium incrustatum）、赤铁矿藻（Rivularia haematites）和绿藻（Gongrosira incrustans）相关的方解石的碳氧稳定同位素组成。夏季沉积的水蛭方解石的δ13C值显著高于冬季沉积的方解石。这被解释为菌落内光合作用的结果。所研究的三种蓝藻的δ13C值相似，在531 m长度的溪流中取样的Homoeothrix菌落显示出13C的逐渐下游富集（2.0‰）。这是由于下游水的二氧化碳脱气，在夏季由苔藓植物的光合作用增强。方解石的后续沉积与藻类的光合作用无关，可能模糊了较老菌落和化石组合的同位素特征。
Abstract The composition of carbon and oxygen stable isotopes was determined for calcite associated with the freshwater cyanobacteria Homoeothrix Crustacea, Phormidium incrustatum, and Rivularia haematites and the green alga Gongrosira incrustans in a UK travertine‐depositing stream. The δ13C values of Rivularia calcites deposited in summer were significantly higher than those deposited during winter. This was interpreted as the result of photosynthetic activity within colonies. The δ13C values were similar for the three cyanobacterium species studied, and colonies of Homoeothrix sampled over a 531‐m length of stream showed progressive downstream enrichment of 13C (2.0‰). This resulted from CO2 degassing of the downstream water, augmented during summer by bryophyte photosynthesis. Subsequent deposition of calcite takes place irrespective of photosynthetic activity of the algae and may blur the isotopic characteristics in older colonies and fossil assemblages.