| Abstract |
The Sea of Marmara is a natural laboratory. It
has a a well-defined
two-layer stratification and two-layer current system driven by the density and
sea-level differences between the Mediterranean and Black Sea. The
ecosystem and the environment of the sea of Marmara is under serious pressures due to the massive human activities, land-based pollution
such as untreated sewage, agricultural
run-off, oils and heavy metals from industry, etc., maritime transport, over fishing, tourism and other economic
activities. There is an urgent need for an ecosystem-based Environmental Management Plan peculiar to the
Sea of Marmara. Therefore, the Marmara Integrated Model System (MARMOD) Project
aims to establish a basin-based Environmental Management Plan
proposal to ensure the Marmara Sea 'Good Environmental Status' criteria.
The
massive nutrient pollution in the Sea of Marmara over the past
years results in the depletion of oxygen in deeper waters since the excessive
nutrient intake subsequently increases the amount of living mass sinking to the
bottom thereby increasing oxygen consumption in the lower water layers during
disintegration. Therefore, the dissolved oxygen amount is one the
most important indicators showing the environmental status in the Sea of
Marmara. Within the scope of MARMOD Phase I project held in 2017, the historical
data were collected primarily through inter-institutional cooperation. The most
drastic result of the project is the serious oxygen decrease in the basin due
to the extent of nutrient pollution in the
Sea of Marmara over the past years. The area of abundant
oxygen in the surface layer is now limited to 15-20 meters with a considerable
decrease in oxygen levels in the bottom waters, being in some areas completely
exhausted. The nutrient loads to the
basin through the Turkish Straits System have also been calculated for the
first time and the integrated model representing the physical and
biogeochemical processes of the Sea of Marmara has been developed. The
one-dimensional model was run prospectively to assess state of the Marmara deep
layer for a period of 6 years, and it was proved that the model performs
hindcast, nowcast and forecast very well. Then the model was run under various
scenarios to support the Management Plan.
Within the scope of the activities of the
MARMOD Phase II Project, the three-dimensional ecosystem-based model will be
developed. Analyses made in the first phase indicate that the estimation of the
nutrient loads are substantially lower than the actual values. The new field |
