Epaminondas Christou

Epaminondas Christou
Hellenic Centre for Marine Research | hcmr · Institute of Oceanography

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75
Publications
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Publications

Publications (75)
Article
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: Faecal pellet production and content along with egg production of the dominant cope�pod species Acartia clausi were studied in the Thermaikos Gulf (NW Aegean Sea) during a pre�bloom and a bloom of the toxic dinoflagellate Dinophysis acuminata. Both faecal pellet production (6.8–8.6 ind−1 d −1 ) and egg production (15.8–47.6 ind−1 d −1 ) appeared...
Chapter
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...
Article
Abstract Harmful invader ctenophore Mnemiopsis leidyi's expansions in the Eurasian Seas, its spatio-temporal population dynamics depending on environmental conditions in recipient habitats have been synthesized. M. leidyi found suitable temperature, salinity and productivity conditions in the temperate and subtropical environments of the semi-enc...
Article
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...
Article
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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...
Article
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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...
Article
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Copepod community along the Mediterranean Moroccan coast was investigated, for the first time, during April 2013. Total abundance varied from 53 to 4557 ind. m-3 and high values were found in coastal waters. Oithona nana and Paracalanus parvus dominated in the entire area and species diversity was decreasing from the West to the East. Hierarchical...
Poster
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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...
Article
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PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-anal...
Article
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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...
Data
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...
Article
Full-text available
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...
Article
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...
Article
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The north-eastern Aegean Sea (NEA) is a marine system of high hydrological complexity, principally induced by the inflow and subsequent advection of the low salinity (<30) Black Sea water (BSW). This water mass occupies the upper layer (~0–20 m) of the NEA and plays a key role in the determination of circulation patterns and the generation of vario...
Article
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The general aim of setting up a central database on benthos and plankton was to integrate long-, medium- and short-term datasets on marine biodiversity. Such a database makes it possible to analyse species assemblages and their changes on spatial and temporal scales across Europe. Data collation lasted from early 2007 until August 2008, during whic...
Article
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Some effects in the biosphere from the Total Solar Eclipse of 29 March 2006 were investigated in field crops and marine zooplankton. Taking into account the decisive role of light on plant life and productivity, measurements of photosynthesis and stomatal behaviour were conducted on seven important field-grown cereal and leguminous crops. A drop in...
Article
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The Mediterranean Sea is located in a crossroad of mid-latitude and subtropical climatic modes that enhance contrasting environmental conditions over both latitudinal and longitudinal ranges. Here, we show that the large-scale environmental forcing is reflected in the basin scale trends of the adult population of the calanoid copepod Centropages ty...
Article
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A new alien species Beroe ovata Mayer 1912 was recorded in the Aegean Sea. It is most likely that this species spread on the currents from the Black Sea. Beroe ovata is also alien to the Black Sea, where it was introduced in ballast waters from the Atlantic coastal area of the northern America. The species is established in the Black Sea and has de...
Article
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Distribution, production and grazing of the copepod community were investigated in the northern Aegean Sea, which is characterized by a permanent thermohaline front. Cruises were conducted along a transect crossing the frontal area during spring and late summer. Biomass and production of autotrophs were measured by size fractionation and heterotrop...
Article
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Centropages typicus is one of the most common, abundant and best studied calanoid copepods in neritic waters of the Mediterranean Sea, which means it can provide useful information about the long-term dynamics of the Mediterranean epipelagic ecosystem. This paper presents the first comparative overview of the seasonal and long-term variability of C...
Article
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This study was carried out in the northern Aegean Sea during late summer and spring. The aim was to examine the spatial and temporal distribution of the zooplankton community across a dynamic frontal area and to investigate how the oceanographic heterogeneity structures the composition of the zooplankton assemblages. The low-salinity and cold Black...
Article
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The scyphomedusa Rhopilema nomadica, recorded in July 2006 from Lakonikos Gulf, on the Ionian coast of Greece, is a Lessepsian alien established in the Levantine Sea. The jellyfish's painful stings may pose a danger to swimmers. Because of its invasiveness and its impact it is considered among the worst invasive marine species in European Seas.
Article
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Copepods and appendicularians are major grazers in the pelagic environment. They have different retention efficiencies for prey and may therefore exert a variable grazing pressure on the spectrum of pico- to micro-plankton. We determined clearance rates of both groups at one station during 24 h in the Gullmar fjord, west Sweden, in autumn 1999. Tot...
Article
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We compare the nature of copepod outfluxes of nonliving matter, the factors controlling their rate and their fate, and finally their role, particularly their relative importance in the carbon and nitrogen cycle. Copepods release dissolved matter through excretion and respiration and particulate matter through production of faecal pellets, carcasses...
Article
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An attempt was made for a comparative study of the mesozooplankton communities between the Aegean and Black Seas. These areas are in connected through the Sea of Marmara, the Bosporus and the Dardanelles straits. The comparison was mainly based on data collected both in coastal and offshore waters, by the Hellenic Centre for Marine Research (Greece...
Article
The study was carried out in the Skagerrak during late summer when population development in the pelagic cycle culminated in the yearly maximum in zooplankton biomass. The cyclonic circulation of surface water masses created the characteristic dome-shaped pycnocline across the Skagerrak. The large dinoflagellate Ceratium furca dominated the phytopl...
Chapter
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The distribution of the ctenophore Mnemiopsis leidyi in the Aegean Sea, influenced by the outflow of Black Sea water through the Dardanelles strait, has been studied since 1990. Swarms were found in the northern Aegean Sea, mainly near coastal areas, but at a lower abundance (max 150 ind. m−2) than in the Black Sea. It has been hypothesized that M....
Article
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The functional response of the appendicularian Oikopleura dioica was investigated with a unialgal diet (Isochrysis galbana, 0-1,600 g C l-1) and with additions of specific concentrations of algae either smaller than the incurrent filter mesh size (Rhodomonas baltica, 90 g C l-1; Thalassiosira weissflogii, 60 g C l-1) or larger algae (Ceratium linea...
Article
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We examined and quantified the contributions of copepods and appendicularians to the vertical flux of carbon during autumn and spring in Gullmar Fjord (west coast of Sweden). Faecal pellet-production rate was determined for major copepod and appendicularian species. In addition, house-production rates were estimated for the appendicularian Oikopleu...
Article
During the intense spring diatom bloom, the spatial (km) and temporal (h) variability of the pelagic food web structure was investigated in the Skagerrak. Three surface water masses could be identified in the study area based on their temperature, salinity and biogeochemical characteristics. When the measured biological parameters were separated in...
Article
This work is a study of plankton food web structure and carbon flow in March and September 1997 in the Aegean Sea, area of outflow of Black Sea waters in the Mediterranean Sea. Biomass and production of autotrophs were measured by size fraction as well as bacterial biomass and production; furthermore, we studied heterotrophic nanoflagellates (HNAN)...
Article
Full-text available
This work is a study of plankton food web structure and carbon flow in March and September 1997 in the Aegean Sea, area of outflow of Black Sea waters in the Mediterranean Sea. Biomass and production of autotrophs were measured by size fraction as well as bacterial biomass and production; furthermore, we studied heterotrophic nanoflagellates (HNAN)...
Article
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In the last two decades of the twentieth century, the ctenophore Mnemiopsis leidyi (A. Agassiz) has invaded the Black, Azov, Marmara and Aegean Seas, and, recently, the Caspian Sea. Here, we compare its spatial and temporal distribution, seasonal dynamics and the time and duration of reproduction. We also discuss factors that control its abundance...
Article
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The vertical distribution (0-300 m) of a numerically important group of small and morphologically similar calanoid copepods (Clausocalanus, Ctenucalanus, and Paracalanus) of the families Pseudocalanidae and Paracalanidae is described from a series of hauls taken in six areas of the eastern Mediterranean Sea during a synoptic survey in October/Novem...
Chapter
Full-text available
The Eastern Mediterranean Sea, except the N.Aegean Sea and the Adriatic Sea, is characterized by a subtropical climate favourable to thermophilic and halophilic species [1] and therefore its plankton consists mainly of subtropical elements [2]. The Ionian and Levantine Seas offer depths often over 3000 m and have a narrow continental shelf. The mai...
Article
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In the present study, we evaluated the ability of dynamic regression on the basis of its efficiency to model and forecast the fortnightly abundance of cladocerans during 1989-1993 in a coastal region of the eastern Saronikos Gulf (Aegean Sea). The following dynamic regression model explained 79% of the variability of the transformed cladoceran abun...
Article
Patterns of abundance of the dominant copepods as well as that of the total copepods, are given for a coastal area of the eastern Mediterranean Sea (Saronikos Gulf, Aegean Sea). The results were based on 124 zooplankton samples collected biweekly during a 5-year period from January 1989 through December 1993. Copepod abundances and environmental pa...
Article
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Dans ce travail, nous analysons les principales caractéristiques des pêcheries marines grecques (composition des captures et densités) pour la période 1982-1989 ; les résultats sont discutés en termes de potentiel trophique des eaux maritimes grecques (abondance et productivité du phytoplancton et du zooplancton) et comparés à ceux obtenus dans d'a...
Article
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Traditionally, diatoms have been associated with productive pelagic food chains that lead, through suspension-feeding planktonic copepods, to top consumers and important fisheries. Here, 15 laboratories located worldwide in 12 different countries and representing a variety of marine, estuarine and freshwater environments present strong evidence tha...
Article
In the present study we compare the overall performance of the 14 mm (from knot-to-knot) diamond-shaped codend (14D), presently used in Hellenic waters, with those of 20 mm square-shaped (20S) and 20 mm diamond-shaped (20D) trawl codends. The experiments took place at 12 stations in the western Aegean Sea and were based on the covered codend method...
Article
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In the present work, seven forecasting techniques were evaluated on the basis of their efficiency to model and provide accurate operational forecasts of the monthly commercial landings of 16 species (or groups of species) in the Hellenic marine waters. The development of operational forecasts was based on the following three general categories of f...
Article
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Traditionally, diatoms have been associated w ~ t h productive pelagic food chains that lead, through suspension-feeding planktonic copepods, to top consumers and important fisheries Here, 15 laborator~es located ivorldw~de in 12 d~ffer-ent countries and representing a variety of marine, estuarine and freshwater environments present strong evidence...
Article
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In the present work we integrate the available quantitative information on the following aspects of the Hellenic Seas: (a) distribution of temperature and salinity, water masses, currents and climate change; (b) distribution of oxygen and nutrients in coastal and open sea waters; (c) plankton abundance, production and assemblages; (d) benthic abund...