PHOSPHORUS CYCLING AND ALGAL-BACTERIAL COMPETITION IN SANDSFJORD, WESTERN NORWAY | |
THINGSTAD, TF ; SKJOLDAL, EF ; BOHNE, RA | |
刊名 | MARINE ECOLOGY-PROGRESS SERIES
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1993 | |
卷号 | 99期号:3页码:239-259 |
ISSN号 | 0171-8630 |
英文摘要 | Microbial phosphorus-cycling, with particular emphasis on algal/bacterial competition, was studied in depth profiles through the halocline separating a brackish top layer, rich in nitrate and poor in phosphate, from the underlying coastal water, poor in both nitrate and phosphate, in the Sandsfjord area, western Norway. At 2 stations along the axis of natural freshwater outflow, physiological P-deficiency of algae and bacteria in the brackish layer was inferred from rapid luxury consumption of added PO43- by organisms in size fractions > 1 mum and 1-0.2 mum, respectively. In a branch of the fjord without natural freshwater outlets, luxury consumption in the brackish layer was less, and without a clear difference between the 2 water layers. High luxury consumption coincided with short (< 30 min) turnover times for PO43- and strong bacterial dominance of (PO43-)-P-32-uptake, suggesting bacterial superiority as competitors during P-limiting conditions. Estimation of P-specific maximum uptake rate and affinity for PO43--uptake from isotope dilution experiments indicated bacterial superiority at low and algal superiority at high concentrations. Although most of the P-32 hydrolyzed from added (gamma-ATP)-P-32 was initially liberated as free (PO4)-P-32 partitioning of incorporated P-32 between size fractions > 1 mum and 1-0.2 mum was found to depend on whether label was added as (gamma-AVP)-P-32 or as (PO43-)-P-32, indicating that coupling of uptake to hydrolysis by cell-bound enzymes could modify the outcome of algal-bacterial phosphorus competition. Disappearance rate of P-32 from the 1-0.2 mum size fraction following initial labeling and a subsequent cold chase with PO43- was used to estimate the flow-rate of phosphorus through the microbial food web. Combined with measured kinetic constants for PO43- uptake, alkaline phosphatases and 5'nucleotidases, a coherent flow-scheme could only be obtained assuming very low (< 1 nmol l-1) concentrations of PO43- and nucleotides. Chemically measured concentrations of dissolved organic phosphorus (DOP) more than 2 orders of magnitude above the estimated nucleotide level and with an estimated turnover time of ca 500 h, are consistent with the view that this large P-reservoir consists mainly of slowly hydrolyzable polymers. |
学科主题 | Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography |
原文出处 | INTER-RESEARCH |
语种 | 英语 |
公开日期 | 2012-02-13 |
内容类型 | 期刊论文 |
源URL | [http://ir.scsio.ac.cn/handle/344004/9296] ![]() |
专题 | 南海海洋研究所_海洋微食物网高被引文献 |
推荐引用方式 GB/T 7714 | THINGSTAD, TF,SKJOLDAL, EF,BOHNE, RA. PHOSPHORUS CYCLING AND ALGAL-BACTERIAL COMPETITION IN SANDSFJORD, WESTERN NORWAY[J]. MARINE ECOLOGY-PROGRESS SERIES,1993,99(3):239-259. |
APA | THINGSTAD, TF,SKJOLDAL, EF,&BOHNE, RA.(1993).PHOSPHORUS CYCLING AND ALGAL-BACTERIAL COMPETITION IN SANDSFJORD, WESTERN NORWAY.MARINE ECOLOGY-PROGRESS SERIES,99(3),239-259. |
MLA | THINGSTAD, TF,et al."PHOSPHORUS CYCLING AND ALGAL-BACTERIAL COMPETITION IN SANDSFJORD, WESTERN NORWAY".MARINE ECOLOGY-PROGRESS SERIES 99.3(1993):239-259. |
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