Effect of CO2, nutrients and light on coastal plankton. II. Metabolic rates

Aquatic Biology

A. Reul¹  M. J. Cabrerizo¹  P. Claquin¹  P. Carrillo¹  P. J. Neale¹  O. Prasil¹  P. León¹  L. Yebra¹  A. L. Amorim¹  M. Segovia¹  M. R. Lorenzo¹  V. Montecino¹  J. M. Mercado¹  S. Salles¹  S. Putzeys¹  C. Sobrino¹  J. M. Medina-Sánchez¹  C. Napoleon¹ 

关键词: Acidification;    Bacterioplankton;    Nutrients;    Phytoplankton;    Primary productivity;    Respiration;    UVR;   

DOI  :  10.3354/ab00606

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: We conducted a microcosm experiment aimed at studying the interactive effects of high CO₂, nutrient loading and irradiance on the metabolism of a planktonic community sampled in the Western Mediterranean near the coast of Málaga. Changes in the metabolism of phytoplankton and bacterioplankton were observed for 7 d under 8 treatment conditions, representing the full factorial combinations of 2 levels each of CO₂, nutrient concentration and solar radiation exposure. The initial plankton sample was collected at the surface from a stratified water column, indicating that phytoplankton were naturally acclimated to high irradiance and low nutrient concentrations. Nutrient addition combined with high irradiance resulted in a significant increase in primary production. Nitrate uptake by phytoplankton was also stimulated under high nutrient conditions. High nutrients, high irradiance and the combination of low CO₂ and high irradiance positively affected bacterial production. Light was the main factor affecting the respiration rates of the community, which were higher at the high light level. After 7 d of incubation, nutrient loading was the only factor that significantly affected the amount of particulate organic carbon (POC) accumulated in the microcosms. Therefore, the changes in metabolic rates produced at high CO₂ had no effect on net production of particulate organic matter. If these results are extrapolated to the natural environment, it could be hypothesized that high levels of CO₂ will have a limited impact on biological pump activity in the northern Alboran Sea since it is assumed that POC export towards deeper layers determines the potential for carbon sequestration.

【 授权许可】

Unknown