Effect of nutrient amendments on bacterioplankton production, community structure, and DOC utilization in the northwestern Sargasso Sea

By C. Carlson, S. Giovannoni, Dennis A. Hansell, S. Goldberg, R. Parsons, M. Otero, K. Vergin, B. R. Wheeler. Aquatic Microbial Ecology, 2002

239 citations recorded by the source corpus.

Bacterial abundance, DOC concentrations, and bacterioplankton community structure (using PCR-based techniques) were measured in 5 seawater culture experiments conducted near the Bermuda Atlantic Time-series Study (BATS) site in the northwestern Sargasso Sea. Cultures were amended with inorganic and organic nutrients, alone or in combination, to test the existence of the 'malfunctioning microbial loop' during late spring and summer at BATS. Objectives of the study were to determine whether (1) alleviating grazing pressure and inorganic nutrient limitation stimulated DOC remineralization by bacterioplankton; (2) a combination of organic and inorganic nutrients affect bacterial production and utilization of seasonally accumulated DOC; and (3) shifts in bacterioplankton community structure are associated with nutrient amendment and DOC utilization. In unamended cultures natural assemblages of surface bacterioplankton did not utilize detectable amounts of naturally occurring 'semi-labile' DOC over time-scales of days to weeks. Neither bacterial production nor utilization of DOC was enhanced with the addition of inorganic N or P (alone or in combination). Labile DOC amendments stimulated bacterial production and DOC utilization, even in the absence of measurable inorganic nutrients, indicating that the bacterioplankton assemblage was initially energy limited, but did not stimulate utilization of seasonally accumulated DOC. The combination of inorganic N and P with labile DOC enhanced both bacterial production and utilization of 'semi-labile' DOC. Changes in bacterioplankton community rDNA gene profiles were minor in the control and inorganic treatments; however, utilization of 'semi-labile' DOC in the organic plus inorganic nutrient treatments coincided with significant changes in bacterioplankton community structure. These data suggest that bacterioplankton community structure, as well as nutrient regime, may be important factors governing the utilization of recalcitrant DOC substrates in the northwestern Sargasso Sea.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/98fb2b4caaaf98764da644425bd4174b944499f3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecology

1. J. Gasol
2. C. Robinson
3. Hongyue Dang
4. C. Carlson
5. S. Giovannoni
6. C. Pedrós-Alió
7. Kevin J. Flynn
8. K. Vergin

In Oceanography

1. Aditee Mitra
2. C. Robinson
3. J. Gasol
4. C. Carlson
5. Farooq Azam
6. Hongyue Dang
7. L. Legendre
8. Jarone Pinhassi

Citations in the corpus

• Mechanisms of Microbial Carbon Sequestration in the Ocean - Future Research Directions (2014, background): “Such organic matter would also be relatively resistant to microbial utilization, enhancing the MCP. Microbial carbon accumulation is known to occur where/when nutrients are limiting (Carlson et al., 2002; Gasol et al., 2009; Lauro et al., 2009; Thomas et al., 1999; Jiao et al., 2010b).”
• Spatiotemporal distributions of rare bacterioplankton populations indicate adaptive strategies in the oligotrophic ocean (2013, background): “Microbiology 144: 3257−3266 Nelson CE, Carlson CA (2012) Tracking differential incorporation of dissolved organic carbon types among diverse lineages of Sargasso Sea bacterioplankton.”
• Pelagic functional group modeling: Progress, challenges and prospects (2006, unknown): “However, recent experiments (e.g., Carlson et al., 2002) and conceptual models provide compelling reasons to believe that the growth rates of specific heterotrophic microbial populations in planktonic ecosystems are linked to the composition and amount of DOM, as well as to the availability of…”
• Castles built on sand : dysfunctionality in plankton models and the inadequacy of dialogue between biologists and modellers (2005, background): “Much description of DOM is couched in terms of lability (Carlson et al., 2002), without describing the actual chemical composition and forgetting that a compound is only biologically labile if there is an organism present that can use it.”
• Seasonal changes in bacterioplankton nutrient limitation and their effects on bacterial community composition in the NW Mediterranean Sea (2006, background): “Indeed, it has been speculated that inconsistent findings of C or P limitation in the Sargasso Sea may be explained by temporal variability (Cotner et al. 1997, Carlson et al. 2002, 2004).”