A Coupled modelling attempt of hydrodynamics and ecosystem of northern levantine basin

Aydoğdu, Ali
A three-dimensional ocean model, ROMS, has been utilized to simulate the hydrodynamics and the ecosystem dynamics of the Northern Levantine Basin circulation. The model is one-way nested inside a coarser resolution Mediterranean Sea eco-hydrodynamics model, forced with realistically updated surface and lateral fluxes of momentum, mass, heat and nutrients. Scenario runs representing present and future time-slices of 5 years each have been used to investigate sensitivity to climate in the near future. Other sensitivity tests depending on model parameters and options have been performed. It is revealed that the Asia Minor Current, dominating the basin circulation, divides the basin into the two basic regions of coastal and open sea characteristics. Although satisfactory results are reached for the general behaviour of the ecosystem, the model tends to overestimate the surface chlorophyll concentration. Sea surface patterns of variables predicted by the model are compared with satellite data indicate general agreement in the seasonal patterns. Based on the selected climate change scenario for 30-40 year difference of the time slices, rises of 0.33◦ C and 0.035 respectively in surface temperature and salinity are estimated in daily average properties. As a result, surface chlorophyll concentrations are increased by 8%. Moreover, significant changes in the periodicity of seasonal phytoplankton blooms are found. Results of the parameter and option sensitivity tests have revealed the need for better representation of surface fluxes and a careful tuning of the mixing achieved by the model, especially at the surface levels. Sensitivity runs also showed that the temperature and salinity at the surface were overestimated because of the need for better representation of the penetration of radiation in the surface waters. The results are promising, whereas there is need for further investigation of basic processes such as the Levantine Intermediate Water (LIW) formation.


A physical-biochemical model of plankton productivity and nitrogen cycling in the Black Sea
Oguz, T; Ducklow, HW; Malanotte-Rizzoli, P; Murray, JW; Shushkina, EA; Vedernikov, VI; Unluata, U (1999-04-01)
A one-dimensional, vertically resolved, physical-biochemical upper ocean model is utilized to study plankton productivity and nitrogen cycling in the central Black Sea region characterized by cyclonic gyral circulation. The model is an extension of the one given by Oguz et al. (1996, J, Geophys. Res. 101, 16585-16599) with identical physical characteristics but incorporating a multi-component plankton structure in its biological module, Phytoplankton are represented by two groups, typifying diatoms and flag...
An indicator-based evaluation of Black Sea food web dynamics during 1960-2000
Akoğlu, Ekin; Salihoğlu, Barış; SOLİDORO, Cosimo (2014-06-01)
Four Ecopath mass-balance models were implemented for evaluating the structure and function of the Black Sea ecosystem using several ecological indicators during four distinctive periods (1960s, 1980-1987,1988-1994 and 1995-2000). The results exemplify how the Black Sea ecosystem structure started to change after the 1960s as a result of a series of trophic transformations, i.e., shifts in the energy flow pathways through the food web. These transformations were initiated by anthropogenic factors, such as e...
Nonlinear dynamics of the Black Sea ecosystem and its response to anthropogenic and climate variations
Akoğlu, Ekin; Salihoğlu, Barış; Department of Marine Biology and Fisheries (2013)
The main objective of this research is to i) provide a quantitative understanding of the changes in the Black Sea ecosystem between 1960 – 1999, ii) to identify its food web dynamics including the infamous anchovy – Mnemiopsis shift in 1989, and iii) utilizing this understanding to explore future progressions of the Black Sea ecosystem under predicted future physical and biogeochemical changes. For this purpose, three different but complementary approaches were used all of which were detailed under three di...
Karakuş, Onur; Fach Salihoğlu, Bettina; Salihoğlu, Barış; Department of Oceanography (2018-11-19)
In this study, a three dimensional, coupled ocean ecosystem model (FESOMREcoM2) is used to investigate the impact of krill on the ecosystem dynamics of the Southern Ocean in modeling studies. A new, second zooplankton group defined to be Antarctic krill is added to an already existing and validated setup of the modelling system. This species was chosen because it is a key organisms in the Southern Ocean. The effect of grazing on net primary production and export production due to the addition of Antarctic k...
Modeling the impact of tidal flows on the biological productivity of the Alboran Sea
Sanchez-Garrido, Jose C.; Naranjo, C.; Macias, D.; Garcia-Lafuente, J.; Oguz, T. (2015-11-01)
The control of phytoplankton production by tidal forcing in the Alboran Sea is investigated with a high-resolution ocean circulation model coupled to an ecosystem model. The aim of the modeling efforts was to elucidate the role of tides in sustaining the high biological productivity of the Alboran Sea, as compared with the rest of the Mediterranean subbasins. It is shown that tidal forcing accounts for an increase of phytoplankton biomass and primary productivity in the basin of about 40% with respect to a ...
Citation Formats
A. Aydoğdu, “A Coupled modelling attempt of hydrodynamics and ecosystem of northern levantine basin,” M.S. - Master of Science, Middle East Technical University, 2012.