Object–based modeling of the coastal marine ecosystem

Abstract

We consider a procedure of modeling of marine ecosystems combining the object-based modeling with traditional methods. The proposed procedure belongs to the junction of several different fields of science. To illustrate this procedure, we present the description of a chemicobiological object-based model of the plankton community of the shallow-water part of the northwest shelf of the Black Sea and some results obtained with the help of this model. The model includes the description of the life cycle of copepods (one of the most widespread and numerous groups of zooplankton. The comparative analysis of the numerical experiments performed under various environmental conditions is realized.The object-based modeling (OBM) is a relatively new but quite promising direction of investigations of complex biological systems. First, the technologies of OBM were developed in the fields of modeling if artificial life and artificial intelligence. The first attempts to apply the object-based approach to the construction of simulating models of biological systems were performed at the end of the 1980s [1-4]. These investigations led to the conclusion that the complex behavior of biological systems formed by numerous components can be a consequence of simple interactions between the individual components and, hence, should be modeled and studied by formulating simple rules applicable to families of relatively simple objects. The first works in this direction were devoted to the simulation of the dynamics of populations of various species of insects and bacteria [4][5][6]. Then the same methods were used for the construction of models of social and economic processes [7][8][9].As applied to the object-based modeling of living systems, it is possible to distinguish three main trends, namely, modeling based on cellular automata, individual-based modeling, and agent-based modeling [10]. The common feature of all these approaches is that the dynamics of systems is modeled from the lower level to the upper level, i.e., from micro-to macroscales, from the smallest and simplest components to the complex behavior on the level of population or community. The object-based models deal with numerous objects for which the formalized rules of their behavior in time are determined by the properties and methods depending on the nature of a specific object. The numerical calculations give a general picture of the dynamics of the entire system. In analyzing the results and checking the degree of adequacy of the model to the actual processes, it is necessary to compute some integral characteristics accepted in the corresponding field of investigations. The distinctions between the indicated approaches to object-based modeling are reduced to the difference between the types of objects used in the models. In the individual-based models (IBM), the role of the object of modeling is played by individual organisms. The vital activity of these objects is realized in the environment in the process of uninterrupted interaction with it, by consuming its resou...

Modeling of the dynamics of age structure of the populations of free-floating copepods in the Black Sea

“…The concentrations of organic and inorganic nitrogen compounds at the beginning of calculations were set equal to the corresponding parameters of the stationary state of the system. These parameters were found in the experiments carried out in [1]. The air temperature was constant for the entire period of modeling, the dynamic friction velocity in water was specified as a random function of time, and the insolation was described by a sinusoid with a period of 1 day.…”

“…This approach naturally combines the marine ecology, numerical modeling of the hydrophysical and hydrochemical processes and fields, and the object-based modeling of living components of the ecosystem [1]. The model is described in detail in [1][2][3]. Hence, in what follows, we present only its brief description.…”

“…A trophic model regulating the processes of nutrition, excretion, and mortality of the organisms is described in [3]. The equations of the dynamics of biomass of phytoplankton are identical to the equations presented in [1]. The dynamics of the field of phytoplankton is determined by the illumination, temperature of water, concentration of biogenic elements, maximum growth and mortality rates of the cells, and the intensity of their grazing by phytophages for which phytoplankton plays the role of the main food resource.…”

Object-Based Modeling of Marine Phytoplankton and Seaweeds

“…The vertical distribution of water temperature is determined by heat flux and wind stress at the surface in accordance with the simple integral model [25]. Two layers with a homogeneous vertical distribution of temperature and chemical compounds can exchange water volumes under certain influences at the air-sea boundary.…”

“…A detailed description of the chemical model and numeric values of the model parameters can be found in [25]. Here, we show the equations for dissolved oxygen in the upper and bottom layers as an example (Equations (18) and (19)).…”