Soultana Zervoudaki

Hellenic Centre for Marine Research | hcmr · Institute of Oceanography

Recommendations to frame problems and solutions for the pelagic habitats’ assessment

According to the methodological standards established by Marine Strategy Framework Directive, the assessment for the pelagic habitat under the Biodiversity Descriptor should be carried out at the regional or sub-regional level. In the case of Mediterranean Sea, the sub-regional assessment seems optimal to take into account biogeographic differences...

Metal and metallothionein (MT) in mixed zooplankton were investigated as means of monitoring metal availability regarding environmental exposure. Spatial and temporal variability of Cd, Cu, Ni, Zn, Fe, Mn and Pb in zooplankton and seawater were studied in Saronikos Gulf (Aegean Sea, Eastern Mediterranean), once every second month during an annual c...

Zooplankton plays a fundamental role in oceanic carbon flux as the primary biological mechanism sequestering the carbon transferred from the atmosphere into surface waters to deeper layers and higher trophic levels. Studies of the zooplanktonic organisms of the Aegean Sea have been initiated in the 1900s, whereas the number of cruises has increased...

Mesozooplankton composition including functional groups in relation to hydrological features is studied in the oligotrophic pelagic ecosystem of the eastern Mediterranean Sea. Combining classic/standard microscopy and advanced digital imaging approach copepod growth rates, ingestion and production rates were estimated using allometric relationships...

Since 2007, the non-indigenous calanoid copepod Pseudodiaptomus marinus Sato, 1913 has been increasingly recorded in numerous European sites, spreading at an unexpectedly fast pace over a short time-span. This species presents specific biological and behavioural traits which make it of particular interest for ecological and applied research topics....

Mesozooplankton vertical pattern was studied down to 2000 m along an east-west transect in the oligotrophic Mediterranean Sea in June 1999. Depth-stratified samples were collected by a WP-2 net (200 µm mesh size). In addition, the copepod grazing impact on autotrophs was assessed in the epipelagic zone by measurement of small and large copepod gut...

The Eastern Mediterranean Sea (EMS) is an ultraoligotrophic semi-enclosed sea with low nutrient levels, low primary production rate, impoverished phytoplankton populations and low zooplankton standing stocks. The Cretan Passage in the western Levantine Sea is one of the least explored areas of the EMS. We measured the mesozooplankton biomass, abund...

Combined analyses of Fatty Acid Trophic Markers (FATM) and Stable Isotopes (SI) were used to characterize food preferences among copepod species/taxa and to trace their food sources in the ultra-oligotrophic Cretan Passage of the Eastern Mediterranean Sea (EMS). FATMs are based on the conservation and transfer of specific source Fatty Acids (FAs) t...

The rapid warming of the wolrd’s oceans during the last few decades has affected distributional patterns of marine planktonic communities. Here, we analyse links between sea warming and changes in copepod community composition over the last 3 decades (1980−2012). We used zooplankton time-series data which included 79 species of copepods collected a...

At present there is no consistent approach for the definition of Good Environmental Status (GES) and targets in the Mediterranean Sea, especially for Biodiversity Descriptors, according to the Article 12 of the Marine Strategy Framework Directive (MSFD). The use of plankton indicators in the Mediterranean Sea refers mostly to pelagic habitats in co...

Introduction/Aim: The MSFD aims the achievement of Good Environmental Status (GES) in marine waters by 2020. Zooplankton is considered to have great potential as an "observer" of environmental changes and pressures (Beaugrand et al., 2010, Serranito et al. 2016). This particular study attempts to develop a zooplankton based indicator, using indices...

Naturally occurring microbial decomposition of organic matter (OM) in coastal marine environments cause increased acidity in deeper layers similar or even exceeding the future predictions for global ocean acidification (OA). Experimental studies in coastal areas characterized by increased inputs of OM and nutrients, coping with intermittent hypoxic...

The effects of atmospheric deposition on plankton community structure were examined during a mesocosm experiment using water from the Cretan Sea (Eastern Mediterranean), an area with a high frequency of atmospheric aerosol deposition events. The experiment was carried out under spring-summer conditions (May 2012). The main objective was to study th...

Assessing the quality of coastal waters is one of the most essential issues in order to ensure environmental protection and public health. During the last decades several empirical models have been proposed for the estimation of key water quality parameters like chlorophyll-a, salinity and temperature. The main validation procedure is based on the...

This volume contains the main results of the EC FP7 “The Ocean of Tomorrow” Project CoCoNet, divided in two sections: 1) a set of guidelines to design networks of Marine Protected Areas in the Mediterranean and the Black Seas; 2) a smart wind chart that will allow evaluating the possibility of installing Offshore Wind Farms in both seas. The concep...

Atmospheric deposition is assumed to stimulate heterotrophic processes in highly oligotrophic marine systems, controlling the dynamics and trophic efficiency of planktonic food webs, and is expected to be influenced by climate change. In the course of an 8-day mesocosm experiment, we examined the channeling, of the Saharan dust (SD) and mixed aeros...

After more than thirty years of oceanographic investigations, the consideration of the Mediterranean as a basin at steady state cannot longer be maintained. The Mediterranean is a changing environment. Several dramatic changes in the oceanographic and biogeochemical conditions have been observed during the past decades, emphasizing the need to inve...

Mixotrophs combine photosynthesis with phagotrophy to cover their demands in energy and essential nutrients. This gives them a competitive advantage under oligotropihc conditions, where nutrients and bacteria concentrations are low. As the advantage for the mixotroph depends on light, the competition between mixo- and heterotrophic bacterivores sho...

In order to identify how ocean acidification will influence biological interactions and fluxes among planktonic organisms and across trophic levels, a large-scale mesocosm experiment was performed in the oligotrophic Northwestern Mediterranean Sea in the framework of the European MedSeA project. Nine mesocosms were deployed in the Bay of Calvi (Cor...

Presentation at Goldschmidt Conference 2016 Session 15i: Geochemical controls on environmental and sedimentary archives

Dispersal plays a key role to connect populations and, if limited, is one of the main processes to maintain and generate regional biodiversity. According to neutral theories of molecular evolution and biodiversity, dispersal limitation of propagules and population stochasticity are integral to shaping both genetic and community structure. We conduc...

Scope The Saronikos Gulf in the Central Aegean Sea is a fairly complex coastal system, being the main receptor of domestic and industrial effluents of Athens metropolis (5,000,000 inh.), and recognized as a heavily impacted marine area [1]. We present an assessment of heavy metal contamination based on the analysis of 95 surface sediment samples ob...

Aurelia spp. are cosmopolitan scyphozoan species and probably the most studied jellyfish in the world. They inhabit nearshore waters, especially closed basins, such as coastal embayments, fjords and estuaries, occupying a great variety of habitats worldwide. Recent studies have addressed the biogeography of the genus Aurelia and reported that it co...

The cyclopoid copepods of the genus Oncaea are an important component of the zooplanktonic community in the Mediterranean Sea due to their numerical abundance and distribution in coastal and open waters. Despite their importance in the marine ecosystem, the food habits of these copepods have not been clarified to date. With the aim of shedding some...

Rising levels of atmospheric CO2 are responsible for a change in the carbonate chemistry of seawater with associated pH drops (acidification) projected to reach 0.4 units from 1950 to 2100. We investigated possible indirect effects of seawater acidification on the feeding, fecundity, and hatching success of the calanoid copepod Acartia grani, media...

P-transport through the microbial food web was investigated in a mesocosm experiment in which orthophosphate was added to oligotrophic Cretan Sea water. As non-exclusive alternatives to traditional phytoplankton–zooplankton succession, two mechanisms for P-transport have previously been proposed: a stoichiometric shift in food quality (Tunnelling);...

Although copepods have been considered tolerant against the direct influence of the ocean acidification (OA) projected for the end of the century, some recent studies have challenged this view. Here, we have examined the direct impact of short-term exposure to a pCO2/pH level relevant for the year 2100 (pHNBS, control: 8.18, low pH: 7.78), on the p...

A large-scale in situ mesocosm experiment was performed in June/July 2012 at Bay of Calvi (Western Mediterranean Sea) in order to better understand the response of zooplankton to ocean acidification. We examined: the mesozooplankton abundance, the egg and nauplius stocks and the feeding rates of Acartia clausi, Centropages typicus at different pCO...

Although copepods have been considered tolerant against the direct influence of the ocean acidification (OA) projected for the end of the century, some recent studies have challenged this view. Here, we have examined the direct impact of short-term exposure to a pCO2/pH level relevant for the year 2100 (pHNBS, control: 8.18, low pH: 7.78), on the p...

Here we conduct the first comprehensive assessment of mesozooplankton abundance, biomass, and taxa composition in Cyprus coastal waters (Levantine Sea). Mesozooplankton abundance and biomass sampled at several locations around the island ranged from 153 - 498 individuals m-3 and 0.7 - 5.2 mg dry weight m-3, respectively, with significantly larger b...

Hypoxic coastal areas are considered of high-priority for Ocean Acidification (OA) research, because the co-occurrence and interaction of low oxygen with other environmental stressors i.e. elevated pCO 2 , warming, and eutrophication may pose them at greater risk. In this work, a hypoxic coastal phenomenon exhibiting relatively reduced pH at the ne...

Rising levels of atmospheric CO2 are responsible for a change in the carbonate chemistry of seawater with associated pH drops (acidification) projected to reach 0.4 units from 1950 to 2100. We investigated possible indirect effects of seawater acidification on the feeding, fecundity, and hatching success of the calanoid copepod Acartia grani, media...

Corresponding editor: Roger Harris Light and nutrient availability are assumed to largely control the dynamics and trophic efficiency of marine planktonic food webs, and are expected to be influenced by climate change (i.e. changes in stratification due to global warming). During an 8-day mesocosm experiment, we investigated the propagation of ligh...

Variability is an inherent characteristic of the natural processes. We could consider natural variability any change that is not induced by human intervention. Variability affects both, the environmental factors and the biological components of the systems (changes in abundance, species composition, structure, etc.) and manifest on space (heterogen...

This study includes the first information on the combined effect of low pH and raised temperature on egg production rate (EP), hatching success (HS), excretion and respiration of the Mediterranean copepod Acartia clausi. Adult individuals of A. clausi and fresh surface seawater were collected at a coastal station in Saronikos Gulf during April 2012...

This study includes the first information on the combined effect of low pH and raised temperature on egg production rate (EP), hatching success (HS), excretion and respiration of the Mediterranean copepod Acartia clausi. Adult individuals of A. clausi and fresh surface seawater were collected at a coastal station in Saronikos Gulf during April 2012...

During the SESAME project a study was undertaken in the northern Aegean Sea and simultaneously in the Turkish Straits System (TSS). The composition and the structure of the pelagic food web were examined in order to understand the transfer of phytoplankton production up the food chain in TSS and the Aegean Sea. The results of this study confirm our...

This study includes the first information on the combined effect of low pH and raised temperature on egg production rate (EP), hatching success (HS), excretion and respiration of the Mediterranean copepod Acartia clausi. Adult individuals of A. clausi and fresh surface seawater were collected at a coastal station in Saronikos Gulf during April 2012...

Vertical distribution of the mesozooplankton community down to 1000 m was investigated in the oligotrophic Aegean Sea during March and September 1997. Total biomass and abundance decreased with depth with a sharp decline <100 m. However, in the northern part, higher biomass values in the 500–1000 m layer than in the 300–500 m layer were observed, d...

This work focuses on the direct measurement of the vertical flux of appendicularian houses in order to assess their importance as a component of vertical carbon flux in coastal areas. For this purpose, arrays of cylindrical sediment traps were deployed for 5 to 8 days at two depths in a coastal area of the northern Aegean Sea (inner Thermaikos Gulf...

This work focuses on the direct measurement of the vertical flux of appendicularian houses in order to assess their importance as a component of vertical carbon flux in coastal areas. For this purpose, arrays of cylindrical sediment traps were deployed for 5 to 8 days at two depths in a coastal area of the northern Aegean Sea (inner Thermaikos Gulf...

Plankton biomass and composition in the pelagic zone of oceans is exposed to changes in availability of light and nutrients due to large-scale ocean circulation and water column stratification. We hypothesized that displacement of plankton from surface to deeper darker waters would not only favor heterotrophy over time, as previously suggested, but...

The Mediterranean and the Black Seas are connected through Bosphorus, Marmara Sea and Dardanelles (Turkish Straits System, TSS). In this study, we examined the spatial distribution of copepods and investigate their production and grazing. The aim was to understand the transfer of phytoplankton/microzooplankton production up the food chain in TSS an...

The short-time scale evolution of plankton carbon partitioning and downward flux in the modified Black Sea water (BSW) mass entering the northeast Aegean Sea was studied using a Lagrangian approach (6-10 April 2008). The free-drifting sediment trap positioned at the bottom of the BSW layer and the control drifter, followed the same path within the...

Historical data on physico-chemical and biological characteristics during the last 30 years were used to examine the seasonal nutrient and plankton dynamics in a semi-enclosed area of the Mediterranean Sea, Elefsis Bay, in phase with the development of intermittently hypoxic and anoxic conditions. Sediment records covering most of the Holocene show...