Modeling and evaluating the ecosystem of sea-grass beds, shallow waters without sea-grass, and an oxygen-depleted offshore area

Understanding Environmental Changes in Temperate Coastal Seas: Linking Models of Benthic Fauna to Carbon and Nutrient Fluxes

“…The same approach has been adopted in the ecosystem models IGBEM, Bay Model 2 and Atlantis (Fulton et al, 2004a,b;Audzijonyte et al, 2017). Several coastal ecosystem models developed for Japanese waters use a similar formulation, but without the weighing coefficients (Sohma et al, 2001(Sohma et al, , 2004(Sohma et al, , 2008(Sohma et al, , 2018. As the bioturbation activity is more strongly related to the activity of fauna than to its biomass, D b has also been related to the net carbon uptake flux in other versions of ERSEM, as feeding can be assumed to correlate with the general activity of the animals (Blackford, 1997;Butenschön et al, 2016).…”

“…This implicit approach has been successfully applied to systems with relatively simple and stable benthic communities (e.g., Soetaert et al, 1996Soetaert et al, , 2000Paraska et al, 2014), but has been insufficient to explain nutrient fluxes in some shallow, near-shore areas (Murray and Parslow, 1997;Holstein and Wirtz, 2009), suggesting that the temporal variability in fauna and flora and associated processes typical for many shallow coastal areas needs to be accounted for by dynamic state variables. However, linking biodiffusion (D b ) to biomass dynamics of functional groups (Ebenhöh et al, 1995;Sohma et al, 2001Sohma et al, , 2004Sohma et al, , 2008Sohma et al, , 2018Vichi, 2002;Fulton et al, 2004a,b;Audzijonyte et al, 2017) may not be enough to account for the great variability in reworking rates measured between coastal areas (Boudreau, 1994;Tromp et al, 1995;Middelburg et al, 1997), and even between replicates from the same site (Morys et al, 2016).…”

“…RTMs usually model the degradation of organic matter as a continuous process over depth, while ecological models generally include sediment organic matter as food for the benthos as a single depth-integrated variable. A good 'compromise' could be to divide the organic matter into a finite number of lability classes with different bio-availability for both faunal assimilation and microbial degradation, as in van Oevelen et al (2011). Sohma et al (2004, 2018) took this approach one step further by also dividing the benthic functional groups into lability classes.…”

Modeling the coastal ecosystem complex: present situation and challenges

“…Amongst these are the European Regional Seas Ecosystem Model (ERSEM) (Allen et al 2012;Baretta et al 1995;BarettaBekker et al 1997;Butenschön et al 2016) and those reviewed by James (2002) and Moll and Radach (2003). Biogeochemical models for Japanese coastal waters have also been developed (Hata et al 2004;Sohma et al 2001Sohma et al , 2004Sohma et al , 2008. Of note, the BHI concept proposed by Hori (2008) focused more on the spatial heterogeneity of habitats within a coastal area, which is different from numerical studies of biogeochemical/material cycles at larger scales, often considering areas with a homogeneous benthic habitat (Cranford et al 2007;Lacroix et al 2007;Nobre et al 2010;Xu and Hood 2006).…”

“…Some existing model frameworks appear to be capable of modeling the CEC, but the components and processes required to develop CEC models have not been thoroughly specified. Nevertheless, there are numerous numerical models of coastal ecosystems (Allen et al 2012;Baretta-Bekker et al 1997;Butenschön et al 2016;Fulton et al 2004a;Hata et al 2004;Kishi et al 1981;Sohma et al 2004), formulated for particular purposes. Models including higher trophic levels (Coll et al 2016;Fennel 2008;Fulton 2010;Halouani et al 2016;Kishi et al 2011;Rose et al 2015) have reproduced complex food webs and/or the migratory behavior of fish.…”