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Papers by Ekaterini Souvermezoglou

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station SEPT-1998-IR34

Hellenic Center of Marine Research, Institut of Oceanography, Greece, May 28, 2008

Research paper thumbnail of Nutrient concentrations in water samples collected at Station APRIL-2000-K1 in the Northeastern Aegean Sea

Research paper thumbnail of Chemical oceanography in the Cretan Sea: Changes associated to the transient

Mediterranean Marine Science, Dec 1, 2000

Research paper thumbnail of Oxygen and nutrient fluxes through the Straits of the Cretan Arc (March 1994–January 1995)

Progress in Oceanography, Dec 1, 1999

The Straits of the Cretan Arc are the gateways through which water exchanges between the Cretan S... more The Straits of the Cretan Arc are the gateways through which water exchanges between the Cretan Sea and the SE Ionian and NW Levantine Seas. Dissolved oxygen and nutrient fluxes have been quantified for the major straits — Antikithira, Kassos and Karpathos — by combining chemical bottle-sample data and current measurements obtained during the PELAGOS Project during 1994–1995. Two water

Research paper thumbnail of Biogeochemical fluxes through the Strait of Otranto (Eastern Mediterranean)

Continental Shelf Research, Jun 1, 1998

A series of seasonal cruises and Eulerian current measurements in the Otranto Strait were carried... more A series of seasonal cruises and Eulerian current measurements in the Otranto Strait were carried out to study the biogeochemical characteristics of the strait and to estimate the exchange of water, dissolved and particulate matter between the Adriatic and the Ionian Sea. Analysis of data shows that on an annual scale, the Adriatic Sea exports dissolved nutrients (nitrate and phosphate) to the Ionian, and imports particulate organic carbon and nitrogen. Estimate of the mean annual water flux for the first time based on direct Eulerian ...

Research paper thumbnail of Vertical diffusion and oxygen consumption during stagnation periods in the deep North Aegean

Deep-sea Research Part I-oceanographic Research Papers, 2003

Ventilation of the deep basins of the North Aegean Sea takes place during relatively scarce event... more Ventilation of the deep basins of the North Aegean Sea takes place during relatively scarce events of massive dense water formation in that region. In the time intervals between such events, the bottom waters of each sub-basin are excluded from interaction with other water masses through advection or isopycnal mixing and the only process that changes their properties is diapycnal mixing with overlying waters. In this work we utilize a simple one-dimensional model in order to estimate the vertical eddy diffusion coefficient K r based on the observed rate of change of density and stratification. Vertical diffusivity is estimated for each of three sub-basins of the North Aegean, one of convex shape of the seabed and the other two of concave topography. It is noteworthy that the convex sub-basin exhibited much higher vertical diffusivity than the two concave sub-basins, a fact consistent with theoretical predictions that internal-waveinduced mixing is higher over the former shape of seabed. Furthermore, the estimates of K r are exploited in computing the vertical transport of dissolved oxygen through diffusion and the rate of oxygen consumption by decaying organic matter. The different levels of the estimated diffusion and oxygen consumption rates testify to the dynamical and biogeochemical characteristics of each basin.

Research paper thumbnail of Anthropogenic CO2 fluxes in the Otranto Strait (E. Mediterranean) in February 1995

Deep-sea Research Part I-oceanographic Research Papers, Nov 1, 2011

This study presents the distribution and fluxes of dissolved inorganic carbon (C T), total alkali... more This study presents the distribution and fluxes of dissolved inorganic carbon (C T), total alkalinity (A T) and anthropogenic carbon (C ant) along the Otranto strait, during February 1995. Based on a limited number of properties (temperature, dissolved oxygen, total alkalinity and dissolved inorganic carbon), the composite tracer TrOCA was used to estimate the concentration of anthropogenic CO 2 in the Otranto strait. Total alkalinity exhibits high values and weak variability throughout the water column of the strait, probably associated with the dense water formation processes in the Adriatic basin that induce a rapid transport of the coastal alkalinity to the deep waters. Elevated C ant concentrations and high anthropogenic pH variations are observed in the bottom layer of the strait, associated with the presence of Adriatic Deep Water (ADW). The study shows that large amounts of C ant have penetrated the highly alkaline Eastern Mediterranean waters, thereby causing a significant pH reduction since the pre-industrial era. Estimates of the transports of C T and C ant through the strait indicate that during February 1995, the Adriatic Sea imports through the Otranto strait natural and anthropogenic carbon and acts as a net sink of carbon for the Ionian Sea. The anthropogenic carbon that is imported to the Adriatic Sea represents less than 1% of the net C T inflow. The Levantine Intermediate Water (LIW) contributes to about one-third of the total C T and C ant inflow. Although the amounts of C ant annually transported by LIW and ADW are almost equal, the contribution of C ant to the C T transported by each water mass is slightly higher in ADW (3.1%) than in LIW (2.6%), as a result of its higher mean C ant concentration. The ADW, despite its weak contribution to the total outflow of C ant , has a vital role for the sequestration and storage of the anthropogenic carbon, as this water mass is the main component of the Eastern Mediterranean Deep Waters and, thus, the anthropogenic CO 2 is transferred in the deep horizons of the Eastern Mediterranean, where it remains isolated for many years.

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station MARCH-2000-IRI15

Research paper thumbnail of Particulate organic carbon and nitrogen at bottle station SEPT-1999-K9

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station MARCH-2000-IRI27

Research paper thumbnail of Ιnsights into the Nutrients and Carbon Pools and Dynamics in the Aegean Sea

Research paper thumbnail of Nutrient distribution in the North Aegean Sea affected by the Black Sea Waters

EGU General Assembly Conference Abstracts, Apr 1, 2015

Research paper thumbnail of Eutrophic Signals in the Chemistry of the Bottom Layer of the Northern Adriatic Sea

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station SEPT-1998-IR09

Research paper thumbnail of Nutrient concentrations in water samples collected at Station SEPT-94-GN3619940280300650 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station JUNE-1998-IR06

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station SEPT-2000-IRI47A

Research paper thumbnail of Nutrient concentrations in water samples collected at Station MARCH-94-GN3619940280100110 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples collected at Station DEC94-JAN95-GN3619940280400010 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples collected at Station DEC94-JAN95-GN3619940280400930 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station SEPT-1998-IR34

Hellenic Center of Marine Research, Institut of Oceanography, Greece, May 28, 2008

Research paper thumbnail of Nutrient concentrations in water samples collected at Station APRIL-2000-K1 in the Northeastern Aegean Sea

Research paper thumbnail of Chemical oceanography in the Cretan Sea: Changes associated to the transient

Mediterranean Marine Science, Dec 1, 2000

Research paper thumbnail of Oxygen and nutrient fluxes through the Straits of the Cretan Arc (March 1994–January 1995)

Progress in Oceanography, Dec 1, 1999

The Straits of the Cretan Arc are the gateways through which water exchanges between the Cretan S... more The Straits of the Cretan Arc are the gateways through which water exchanges between the Cretan Sea and the SE Ionian and NW Levantine Seas. Dissolved oxygen and nutrient fluxes have been quantified for the major straits — Antikithira, Kassos and Karpathos — by combining chemical bottle-sample data and current measurements obtained during the PELAGOS Project during 1994–1995. Two water

Research paper thumbnail of Biogeochemical fluxes through the Strait of Otranto (Eastern Mediterranean)

Continental Shelf Research, Jun 1, 1998

A series of seasonal cruises and Eulerian current measurements in the Otranto Strait were carried... more A series of seasonal cruises and Eulerian current measurements in the Otranto Strait were carried out to study the biogeochemical characteristics of the strait and to estimate the exchange of water, dissolved and particulate matter between the Adriatic and the Ionian Sea. Analysis of data shows that on an annual scale, the Adriatic Sea exports dissolved nutrients (nitrate and phosphate) to the Ionian, and imports particulate organic carbon and nitrogen. Estimate of the mean annual water flux for the first time based on direct Eulerian ...

Research paper thumbnail of Vertical diffusion and oxygen consumption during stagnation periods in the deep North Aegean

Deep-sea Research Part I-oceanographic Research Papers, 2003

Ventilation of the deep basins of the North Aegean Sea takes place during relatively scarce event... more Ventilation of the deep basins of the North Aegean Sea takes place during relatively scarce events of massive dense water formation in that region. In the time intervals between such events, the bottom waters of each sub-basin are excluded from interaction with other water masses through advection or isopycnal mixing and the only process that changes their properties is diapycnal mixing with overlying waters. In this work we utilize a simple one-dimensional model in order to estimate the vertical eddy diffusion coefficient K r based on the observed rate of change of density and stratification. Vertical diffusivity is estimated for each of three sub-basins of the North Aegean, one of convex shape of the seabed and the other two of concave topography. It is noteworthy that the convex sub-basin exhibited much higher vertical diffusivity than the two concave sub-basins, a fact consistent with theoretical predictions that internal-waveinduced mixing is higher over the former shape of seabed. Furthermore, the estimates of K r are exploited in computing the vertical transport of dissolved oxygen through diffusion and the rate of oxygen consumption by decaying organic matter. The different levels of the estimated diffusion and oxygen consumption rates testify to the dynamical and biogeochemical characteristics of each basin.

Research paper thumbnail of Anthropogenic CO2 fluxes in the Otranto Strait (E. Mediterranean) in February 1995

Deep-sea Research Part I-oceanographic Research Papers, Nov 1, 2011

This study presents the distribution and fluxes of dissolved inorganic carbon (C T), total alkali... more This study presents the distribution and fluxes of dissolved inorganic carbon (C T), total alkalinity (A T) and anthropogenic carbon (C ant) along the Otranto strait, during February 1995. Based on a limited number of properties (temperature, dissolved oxygen, total alkalinity and dissolved inorganic carbon), the composite tracer TrOCA was used to estimate the concentration of anthropogenic CO 2 in the Otranto strait. Total alkalinity exhibits high values and weak variability throughout the water column of the strait, probably associated with the dense water formation processes in the Adriatic basin that induce a rapid transport of the coastal alkalinity to the deep waters. Elevated C ant concentrations and high anthropogenic pH variations are observed in the bottom layer of the strait, associated with the presence of Adriatic Deep Water (ADW). The study shows that large amounts of C ant have penetrated the highly alkaline Eastern Mediterranean waters, thereby causing a significant pH reduction since the pre-industrial era. Estimates of the transports of C T and C ant through the strait indicate that during February 1995, the Adriatic Sea imports through the Otranto strait natural and anthropogenic carbon and acts as a net sink of carbon for the Ionian Sea. The anthropogenic carbon that is imported to the Adriatic Sea represents less than 1% of the net C T inflow. The Levantine Intermediate Water (LIW) contributes to about one-third of the total C T and C ant inflow. Although the amounts of C ant annually transported by LIW and ADW are almost equal, the contribution of C ant to the C T transported by each water mass is slightly higher in ADW (3.1%) than in LIW (2.6%), as a result of its higher mean C ant concentration. The ADW, despite its weak contribution to the total outflow of C ant , has a vital role for the sequestration and storage of the anthropogenic carbon, as this water mass is the main component of the Eastern Mediterranean Deep Waters and, thus, the anthropogenic CO 2 is transferred in the deep horizons of the Eastern Mediterranean, where it remains isolated for many years.

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station MARCH-2000-IRI15

Research paper thumbnail of Particulate organic carbon and nitrogen at bottle station SEPT-1999-K9

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station MARCH-2000-IRI27

Research paper thumbnail of Ιnsights into the Nutrients and Carbon Pools and Dynamics in the Aegean Sea

Research paper thumbnail of Nutrient distribution in the North Aegean Sea affected by the Black Sea Waters

EGU General Assembly Conference Abstracts, Apr 1, 2015

Research paper thumbnail of Eutrophic Signals in the Chemistry of the Bottom Layer of the Northern Adriatic Sea

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station SEPT-1998-IR09

Research paper thumbnail of Nutrient concentrations in water samples collected at Station SEPT-94-GN3619940280300650 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples from the Aegean Sea at Station JUNE-1998-IR06

Research paper thumbnail of Temperature and salinity in the water column of the Ionian Sea at Station SEPT-2000-IRI47A

Research paper thumbnail of Nutrient concentrations in water samples collected at Station MARCH-94-GN3619940280100110 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples collected at Station DEC94-JAN95-GN3619940280400010 in the Aegean Sea

Research paper thumbnail of Nutrient concentrations in water samples collected at Station DEC94-JAN95-GN3619940280400930 in the Aegean Sea