Comparative simulations of dissolved organic matter cycling in idealized oceanic, coastal, and estuarine surface waters

Keller, David P.; Hood, Raleigh R.

doi:10.1016/j.jmarsys.2012.01.002

Cited by 25 publications

(21 citation statements)

References 115 publications

(194 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We are aware of only one other attempt to integrate viruses into a NPZ framework, including both organic and inorganic nutrients, in the context of marine microbial communities (Keller and Hood, 2013). Viral dynamics in this model assumes that viral decay depends on virus density squared, rather than being proportional to virus density.…”

Section: Discussionmentioning

confidence: 99%

A multitrophic model to quantify the effects of marine viruses on microbial food webs and ecosystem processes

et al. 2015

View full text Add to dashboard Cite

Viral lysis of microbial hosts releases organic matter that can then be assimilated by nontargeted microorganisms. Quantitative estimates of virus-mediated recycling of carbon in marine waters, first established in the late 1990s, were originally extrapolated from marine host and virus densities, host carbon content and inferred viral lysis rates. Yet, these estimates did not explicitly incorporate the cascade of complex feedbacks associated with virus-mediated lysis. To evaluate the role of viruses in shaping community structure and ecosystem functioning, we extend dynamic multitrophic ecosystem models to include a virus component, specifically parameterized for processes taking place in the ocean euphotic zone. Crucially, we are able to solve this model analytically, facilitating evaluation of model behavior under many alternative parameterizations. Analyses reveal that the addition of a virus component promotes the emergence of complex communities. In addition, biomass partitioning of the emergent multitrophic community is consistent with well-established empirical norms in the surface oceans. At steady state, ecosystem fluxes can be probed to characterize the effects that viruses have when compared with putative marine surface ecosystems without viruses. The model suggests that ecosystems with viruses will have (1) increased organic matter recycling, (2) reduced transfer to higher trophic levels and (3) increased net primary productivity. These model findings support hypotheses that viruses can have significant stimulatory effects across whole-ecosystem scales. We suggest that existing efforts to predict carbon and nutrient cycling without considering virus effects are likely to miss essential features of marine food webs that regulate global biogeochemical cycles.

show abstract

Section: Discussionmentioning

confidence: 99%

A multitrophic model to quantify the effects of marine viruses on microbial food webs and ecosystem processes

et al. 2015

View full text Add to dashboard Cite

show abstract

“…On top of that, refractory material exposed to sunlight can be phototransformed into labile material, or, on the contrary, labile material may become bleached and then less degradable (Deutsch et al 2012). Rates of phototransformation processes are however not well described (Keller and Hood 2013) and for that reason poorly constratined in the model. Marine and terrestrial contributions to DOC in different areas of the Baltic Sea have been estimated based on carbon isotope signatures (Alling et al 2008;Deutsch et al 2012).…”

Section: Pools and Ratiosmentioning

confidence: 99%

Key processes in the coupled carbon, nitrogen, and phosphorus cycling of the Baltic Sea

et al. 2017

View full text Add to dashboard Cite

In this study we examine pools of carbon (C), nitrogen (N), and phosphorus (P) in the Baltic Sea, both simulated and reconstructed from observations. We further quantify key fluxes in the C, N, and P cycling. Our calculations include pelagic reservoirs as well as the storage in the active sediment layer, which allows a complete coverage of the overall C, N, and P cycling on a system-scale. A striking property of C versus N and P cycling is that while the external supplies of total N and P (TN and TP) are largely balanced by internal removal processes, the total carbon (TC) supply is mainly compensated by a net export out of the system. In other words, external inputs of TN and TP are, in contrast to TC, rather efficiently filtered within the Baltic Sea. Further, there is a net export of TN and TP out of the system, but a net import of dissolved inorganic N and P (DIN and DIP). There is on the contrary a net export of both the organic and inorganic fractions of TC. While the pelagic pools of TC and TP are dominated by inorganic compounds, TN largely consists of organic N because allochthonous organic N is poorly degradable. There are however large basin-wise differences in C, N, and P elemental ratios as well as in inorganic versus organic fractions. These differences reflect both the differing ratios in external loads and differing oxygen conditions determining the redox-dependent fluxes of DIN and DIP.

show abstract

“…Yet, modeling DOM is still a challenge in itself given its complex composition as a heterogeneous biochemical mixture scattered along a size continuum, from free monomers to large particles. As a result, some models attempt to capture some of its complexity (Keller and Hood, 2013;Hasumi and Nagata, 2014), while others explicitly model the role of heterotrophic bacteria but with a simplistic approach to organic matter (e.g., Liu et al, 2015).…”

Section: The Inclusion Of Viruses In Marine Modelsmentioning

confidence: 99%

“…Hasumi and Nagata (2014) for example, model the cycle of DOM at a global scale including the microbial loop with heterotrophic bacteria, the effect of viral lysis in their mortality (although viruses are not explicitly resolved), and a rather detailed parameterization of organic matter, but having only one general group for phytoplankton and another for zooplankton, two nutrients (N and Fe), and lacking mixotrophy. Previously Keller and Hood (2013) had proposed a C-N model with a significant degree of complexity to study the cycling of DOM in idealized oceanic conditions, including two size classes of phytoplankton, two size classes of zooplankton, heterotrophic bacteria and virus, nutrients (nitrate and ammonium), DIC, detritus and several pools of DOM (labile, semi-labile, and refractory for both N and C). In this model, viruses infect bacteria and both phytoplankton groups with the resulting mortality calculated based on a fixed infection rate for each group and dependent on virus and host densities (type-I functional response), while the decay of viruses is calculated with a quadratic mortality rate.…”

Section: Model Components and Examplesmentioning

confidence: 99%

“…• The classification of DOM into a larger number of categories and the identification of different processes controlling different fractions of DOM (Keller and Hood, 2013;Hasumi and Nagata, 2014); • The inclusion of P, critically important for viral replication (Wilson et al, 1996;Monier et al, 2012), but also consider multiple nutrients (organic and inorganic), as they have a significant influence on the physiologic processes of phytoplankton cells and limit their growth; • A latent period between infection and lysis, proportions of lysogenic vs. lytic virus infection under different nutrient availability (Béchette et al, 2013), and going beyond the type-I interactions between viruses and hosts and the exponential decay of viruses; • Taking upon the ERSEM model-type approach with multielement cycles, variable stoichiometry of both living entities and OM, and several functional groups; • Move toward the new paradigm in food webs where mixotrophy has a central role (Mitra et al, 2014;Berge et al, 2016).…”

Section: Final Remarksmentioning

confidence: 99%

See 1 more Smart Citation

Bridging the Gap between Knowing and Modeling Viruses in Marine Systems—An Upcoming Frontier

Mateus

2017

Front. Mar. Sci.

View full text Add to dashboard Cite

Viruses are the most abundant biological entities in the world's oceans. Their potential control on the dynamics and diversity of bacterioplankton and some phytoplankton groups, and consequent effect on the flow of energy and matter in food webs, may be argued as beyond dispute. Paradoxically, their importance seems to be persistently underestimated by marine modelers, frequently by exclusion, despite the uninterrupted volume of knowledge advanced during the past decades. Bridging the gap between knowing and modeling the role of viruses is, undoubtedly, one of the upcoming frontiers to be crossed in modeling the plankton. This paper has a two-fold objective: (1) review the knowledge on the roles of viruses in marine systems that has been put forward over the past decades, and (2) see how viruses have been incorporated into marine ecosystem models, along with the factors that are limiting their inclusion.

show abstract

Comparative simulations of dissolved organic matter cycling in idealized oceanic, coastal, and estuarine surface waters

Cited by 25 publications

References 115 publications

A multitrophic model to quantify the effects of marine viruses on microbial food webs and ecosystem processes

A multitrophic model to quantify the effects of marine viruses on microbial food webs and ecosystem processes

Key processes in the coupled carbon, nitrogen, and phosphorus cycling of the Baltic Sea

Bridging the Gap between Knowing and Modeling Viruses in Marine Systems—An Upcoming Frontier

Contact Info

Product

Resources

About