An intermediate complexity marine ecosystem model for the global domain

Abstract

A new marine ecosystem model designed for the global domain is presented, and model output is compared with field data from nine different locations. Field data were collected as part of the international Joint Global Ocean Flux Study (JGOFS) program, and from historical time series stations. The field data include a wide variety of marine ecosystem types, including nitrogen-and iron-limited systems, and different physical environments from high latitudes to the mid-ocean gyres. Model output is generally in good agreement with field data from these diverse ecosystems. These results imply that the ecosystem model presented here can be reliably applied over the global domain.The model includes multiple potentially limiting nutrients that regulate phytoplankton growth rates. There are three phytoplankton classes, diatoms, diazotrophs, and a generic small phytoplankton class. Growth rates can be limited by available nitrogen, phosphorus, iron, and/or light levels. The diatoms can also be limited by silicon. The diazotrophs are capable of nitrogen fixation of N 2 gas and cannot be nitrogen-limited. Calcification by phytoplankton is parameterized as a variable fraction of primary production by the small phytoplankton group. There is one zooplankton class that grazes the three phytoplankton groups and a large detrital pool. The large detrital pool sinks out of the mixed layer, while a smaller detrital pool, representing dissolved organic matter and very small particulates, does not sink. Remineralization of the detrital pools is parameterized with a temperature-dependent function. We explicitly model the dissolved iron cycle in marine surface waters including inputs of iron from subsurface sources and from atmospheric dust deposition. r

Skill assessment of three earth system models with common marine biogeochemistry

“…Aragonite is not considered for the chemical dissolution of calcium carbonate in the water column. The proportion of calcifying phytoplankton is parametrized following the formulation of Moore et al (2002), because PISCES does not prognostically represent this phytoplankton functional type. One the other hand, the dissolution rate of calcite follows the parametrization of Gehlen et al (2007): there is no dissolution is allowed when waters are supersaturated, but dissolution increases with the level of under-saturation.…”

Widespread metabolic potential for nitrite and nitrate assimilation among Prochlorococcus ecotypes

“…In many regions of the oligotrophic subtropical and tropical oceans, field studies and biogeochemical models suggest that nitrogen availability has an important role in regulating primary productivity (2,3). In these regions, the marine cyanobacterium Prochlorococcus is often the numerically dominant phytoplankton group and an important contributor to primary production (4).…”

A decade of synthesis and modeling in the US Joint Global Ocean Flux Study

“…One approach is to include diverse geochemical functional groups (e.g., calcifiers, silicifiers, N-fixers, etc. ) in models (Iglesias-Rodriguez et al, 2002), with independent growth and nutrient uptake behavior for the different groups (e.g., Moore et al, 2002a;Moore et al, 2004). Hood et al (2006) provide a comprehensive review of the topic and detail the state of the art at representing all the major functional groups.…”