Occurrence of Nitrogen Fixing Cyanobacterium Trichodesmium under Elevated pCO2 Conditions in the Western Bay of Bengal. (22nd July 2013)

• Record Type: Journal Article
• Authors: Shetye, Suhas; Sudhakar, Maruthadu; Jena, Babula; Mohan, Rahul
• Other Names: Kantha Lakshmi Academic Editor.
• Is Part Of: International journal of oceanography. Volume 2013(2013)
• Publication Date: 2013-07-22
• Subjects: Oceanography -- Periodicals; Oceanography; Periodicals; Electronic journals; 551.46
• DOI: 10.1155/2013/350465
• Languages: English
• ISSNs: 1687-9406

Abstract

Abstract : Recent studies on the diazotrophic cyanobacterium Trichodesmium showed that increasing CO2 partial pressure ( p CO2 ) enhances N2 fixation and growth. We studied the in situ and satellite-derived environmental parameters within and outside a Trichodesmium bloom in the western coastal Bay of Bengal (BoB) during the spring intermonsoon 2009. Here we show that the single most important nitrogen fixer in today's ocean, Trichodesmium erythraeum, is strongly abundant in high (≥300 μ atm) p CO2 concentrations. N : P ratios almost doubled (~10) at high p CO2 region. This could enhance the productivity of N-limited BoB and increase the biological carbon sequestration. We also report presence of an oxygen minimum zone at Thamnapatnam. Earlier studies have been carried out using lab cultures, showing the increase in growth rate of T. erythraeum under elevated p CO2 conditions, but to our knowledge, this study is the first to report that in natural environment also T. erythraeum prefers blooming in high p CO2 concentrations. The observed CO2 sensitivity of T. erythraeum could thereby provide a strong negative feedback to rising atmospheric CO2 but would also drive towards phosphorus limitation in a future high CO2 world.