Microbial loop carbon cycling in ocean environments studied using a simple steady-state model

By Thomas R. Anderson, H. Ducklow. 2001

131 citations recorded by the source corpus.

A simple steady-state model is used to examine the microbial loop as a pathway for organic C in marine systems, constrained by observed estimates of bacterial to primary production ratio (BP:PP) and bacterial growth efficiency (BGE). Carbon sources (primary production including extracellular release of dissolved organic carbon, DOC), cycling via zooplankton grazing and viral lysis, and sinks (bacterial and zooplankton respiration) are represented. Model solutions indicate that, at least under near steady-state conditions, recent estimates of BP:PP of about 0.1 to 0.15 are consistent with reasonable scenarios of C cycling (low BGE and phytoplankton extracellular release) at open ocean sites such as the Sargasso Sea and subarctic North Pacific. The finding that bacteria are a major (50%) sink for primary production is shown to be consistent with the best estimates of BGE and dissolved organic matter (DOM) production by zooplankton and phytoplankton. Zooplankton-related processes are predicted to provide the greatest supply of DOC for bacterial consumption. The bacterial contribution to C flow in the microbial loop, via bacterivory and viral lysis, is generally low, as a consequence of low BGE. Both BP and BGE are hard to quantify accurately. By indicating acceptable combinations of parameter values for given BP:PP, the model provides a simple tool for examining the reliability of BP and BGE estimates.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/46cc6bf16baf41e10618b3570fde6ad3008d7394

How researchers see this paper

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

In Ecology

In Oceanography

Citations in the corpus

Heterotrophic Bacterial Respiration (2008, background): “Anderson and Ducklow (2001) used a steady-state microbial loop model to investigate the relationships between primary production, bacterial respiration and production, BGE, and phytoplankton excretion of DOC at three open-ocean sites.”
Microzooplankton production in the oceans (2004, background): “Such estimates are 2e5 times the mean production rates of heterotrophic bacteria for these regions (Anderson and Ducklow, 2001).”
Effect of nutrient availability on carbon and nitrogen incorporation and flows through benthic algae and bacteria in near-shore sandy sediment (2007, methodology): “According to the concepts put forward by Caron (1994), Legendre & Rassoulzadegan (1995), and Anderson & Ducklow (2001), one would expect that with increasing nutrient limitation there would be an increased coupling between algae and bacteria through the increased exudation of DOC by algae leading…”
Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems (2004, methodology): “To this, we can reasonably add 5% of PP to account for the feeding of bacterivorous protists on net bacterial production, which we take as 10– 15% of PP (Anderson and Ducklow 2001), assuming that some goes to viral lysis.”
Zooplankton and the Ocean Carbon Cycle. (2017, background): “To this we add 10% of global PP (5 Gt C y−1) as microzooplankton consumption of bacterial secondary production, which has been estimated to be 10–15% of PP on average (Anderson & Ducklow 2001), the excess going to viral lysis.”
Numerical analysis of the food web of an intertidal mudflat ecosystem on the Atlantic coast of France (2003, unknown): “In our system, the average value for BP/NPP was 38%, higher than the values of 20 to 30% reported for pelagic systems (Cole et al. 1988 in Anderson & Ducklow 2001).”
Fluxes of carbon in the upper ocean: regulation by food-web control nodes (2002, unknown): “…an important mortality term, the contribution of this process to overall carbon cycling in the ocean is poorly quantified (Fuhrman 1999, 2000, Middelboe & Lyck 2002), and based upon recent modelling studies, it is probably not a major factor mediating the flow of carbon (Anderson & Ducklow 2001).”
Respiration and its measurement in surface marine waters (2005, methodology): “…above, several authors have used equations and models of carbon flow through the microbial food web to estimate the respiration attributable to a particular plankton group, for example, bacteria or size class, for example, <5 µm (Fasham et al. 1999; Ducklow et al. 2000; Anderson and Ducklow 2001).”