Antonia Giannakourou - Academia.edu (original) (raw)
Papers by Antonia Giannakourou
Harmful Algae, 2008
... Taleb et al. (2001) reported that clams accumulate PSP toxins to a lesser degree than other s... more ... Taleb et al. (2001) reported that clams accumulate PSP toxins to a lesser degree than other species; however, members of the family Veneridae can become very toxic by accumulating other toxins such as domoic acid (Vale and Sampayo, 2001). ...
Continental Shelf Research
Abstract The abundance of Transparent Exopolymer Particles (TEP) was determined on a seasonal bas... more Abstract The abundance of Transparent Exopolymer Particles (TEP) was determined on a seasonal basis (autumn, spring and summer) along a north-south transect in the NE Aegean Sea and the vicinity of the Dardanelles Straits. Their distribution patterns were studied in respect to hydrographic conditions and water mass characteristics in the area, as well as particulate organic carbon (POC) concentrations, changes in standing stocks of chlorophyll-α and bacterial production. TEP concentrations ranged from 15.4 to 188 µg GX eq L-1. Their spatial distribution patterns within the euphotic zone displayed significant seasonal variability, which appears to closely reflect the temporal variation of the water column structure, resulting from the encounter and interplay of the Black Sea and Levantine Water masses, and the associated biogeochemical processes. Minimum TEP concentrations during autumn could be likely attributed to a minor quantity of TEP and/or its dissolved precursors exuded by phytoplankton and their enhanced degradation due to their long residence time in the water column. During spring, high TEP production was mediated by actively growing phytoplankton, while during summer a positive link to the intense stratification of the water column and the enhanced bacterial growth within the Black Sea Water layer was observed. The results reported in this study highlight the fact that TEP carbon represents a significant fraction of the POC pool. Moreover, TEP production is critical in promoting particle coagulation rates, playing an important role in carbon cycling/transportation out of the euphotic zone.
Estuarine, Coastal and Shelf Science
Harmful algae, 2018
The marine dinoflagellate Azadinium poporum produce azaspiracids (AZA) and has been recorded wide... more The marine dinoflagellate Azadinium poporum produce azaspiracids (AZA) and has been recorded widely in the world. However, information on its biogeography is still limited, especially in view of the fact that A. poporum comprises several genetically differentiated groups. A total of 18 strains of A. poporum were obtained from the Eastern Mediterranean area by incubating surface sediment collected from Ionian Sea of Greece. The morphology of these strains was examined with light microscopy and scanning electron microscopy. Small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from all cultured strains. Molecular phylogeny based on concatenated SSU, LSU and ITS sequences confirmed three ribotypes within A. poporum and revealed two subclades within ribotypes A and C. Greek strains of A. poporum ribotype A were nested within ribotype A2 together with strains from Western Mediterranean Sea and French A...
Frontiers in Marine Science
Tsagaraki et al. Deposition Effects on E. Mediterranean Plankton Communities and increase in temp... more Tsagaraki et al. Deposition Effects on E. Mediterranean Plankton Communities and increase in temperature, which can lead to more persistent changes in plankton community structure. Here we demonstrate how a single dust deposition event leads to enhancement of phytoplankton and microzooplankton and can eventually, through copepods, transport more nutrients up the food web in the Eastern Mediterranean Sea.
Frontiers in Marine Science
The effect of episodicity of Saharan dust deposition on the pelagic microbial food web was studie... more The effect of episodicity of Saharan dust deposition on the pelagic microbial food web was studied in the oligotrophic Eastern Mediterranean by means of a mesocosm experiment in May 2014. Two different treatments in triplicates (addition of natural Saharan dust in a single-strong pulse or in three smaller consecutive doses of the same total quantity), and three unamended controls were employed; chemical and biological parameters were measured during a 10-day experiment. Temporal changes in primary (PP) and bacterial (BP) production, chlorophyll a (Chl a) concentration and heterotrophic bacteria, Synechococcus and mesozooplankton abundance were studied. The results suggested that the auto-and hetero-trophic components of the food web (at least the prokaryotes) were enhanced by the dust addition (and by the nitrogen and phosphorus added through dust). Furthermore, a 1-day delay was observed for PP, BP, and Chl a increases when dust was added in three daily doses; however, the maximal values attained were similar in the two treatments. Although, the effect was evident in the first osmotrophic level (phytoplankton and bacteria), it was lost further up the food web, masked under the impact of grazing exerted by predators such as heterotrophic flagellates, ciliates and dinoflagellates. This was partly proved by two dilution experiments. This study demonstrates the important role of atmospheric deposition and protist grazing when evaluating the effect on oligotrophic systems characterized by increased numbers of trophic levels.
Frontiers in Marine Science, 2017
Frontiers in Marine Science, 2017
The impact of viral lysis and grazing by flagellates on bacterioplankton production was assessed ... more The impact of viral lysis and grazing by flagellates on bacterioplankton production was assessed during a mesocosm experiment in the Eastern Mediterranean Sea, in response to Saharan dust (SD) vs. mixed aerosols (A) addition. The results highlight a positive effect on bacterial abundance, production and growth rate (∼1.2, ∼2.4, and ∼1.9-fold higher than the controls) in both SD and A, which was also confirmed by the increased portion of high DNA content bacteria (up to 48% of the bacterial community). Lytic viral production and the portion of bacterial production lost due to viral lysis were lower in SD and A after dust addition than in the controls (0.33 ± 0.17 × 10 6 virus-like particles mL −1 h −1 and 6 ± 4%, respectively). Potential ingestion rate of bacteria by flagellates increased upon dust enrichment, but did not differ between mesocosms. Larger predators possibly down regulated flagellate abundance, and the calculated portion of bacterial production lost due to flagellate grazing was probably an artifact. Higher frequency of lysogenic cells in A compared to SD and the controls four days after dust addition may reflect faster phosphorus limitation in A, due to receiving less dissolved inorganic phosphorus and more dissolved inorganic nitrogen than SD.
Frontiers in Marine Science, 2016
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Frontiers in Marine Science, 2016
composition than did that of SD. Our findings show that episodic atmospheric deposition events mi... more composition than did that of SD. Our findings show that episodic atmospheric deposition events might affect the microbial community with regards to their abundance, activity and composition over a short period of time, and thus regulate the function of the microbial community and carbon cycling in oligotrophic waters.
Frontiers in Marine Science, 2016
Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., ... more Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., Sahara and Middle East) are deposited annually on the surface of the Eastern Mediterranean Sea. These depositions can provide high amounts of micro (such as Fe, Zn, Co) and macro nutrients (such as P and N) to supplement nutrient-poor surface waters-that typically limit primary productivity and also dinitrogen (N 2) fixation in many marine environments. Here, we studied the impact of the atmospheric deposition of dust and aerosols on N 2 fixation in the Cretan Sea (Eastern Mediterranean Sea). Mixed polluted aerosols (hereafter A) and Saharan dust (hereafter SD) were added to nine mesocosms (3-m 3 each) containing surface mixed layer seawater (∼10 m), and N 2 fixation was evaluated for 6 days during May 2012 (springtime). The addition of SD triggered a rapid (30 h) and robust (2-4-fold) increase in N 2 fixation rates that remained high for 6 days and contributed 3-8% of the primary productivity. The A addition also resulted in higher N 2 fixation rates compared to the unamended control mesocosms, although the responses were less profound (1.5-2-fold) and accounted for only 2-4% of the primary productivity. The microbial community responded differently to the two additions. Heterotrophic bacterial N 2 fixers dominated the diazotroph community in A and the control mesocosms, while the non-filamentous cyanobacterial group Trichodesmium prevailed in the SD treatment (68% of all the operational taxonomic units, verified by qPCR analyses). Our results indicate that the aerosol source, its route prior to deposition, and its specific chemical composition, can alter the diazotrophic diversity and activity in the Eastern Mediterranean Sea and may thus impact both the N and C dynamics in this impoverished environment.
Mediterranean Marine Science, 2014
Τhe entire pelagic microbial food web was studied during the winter-spring period in the frontal ... more Τhe entire pelagic microbial food web was studied during the winter-spring period in the frontal area of the North Aegean Sea. Abundance of viruses, heterotrophic bacteria, cyanobacteria, auto- and hetero-trophic flagellates, and ciliates, as well as bacterial production, were measured at three stations (MD1, MD2, MD3) situated along a N-S transect between the area directly influenced by the inflowing Black Sea water and the area covered by the Levantine water. Samples were collected in December 2009, and January, March, April, and May 2011. Station MD1 exhibited the highest values of abundance and integrated biomass of all microbial groups and bacterial production during all months, and MD3 the lowest. Bacteria dominated the total integrated biomass at all stations and months, followed by cyanobacteria, auto-, hetero-trophic flagellates and ciliates. On a temporal scale, the microbial food web was less important in March as all microbial parameters at all stations showed the lowest...
Frontiers in Marine Science, 2016
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Estuarine, Coastal and Shelf Science, 2016
Phycologia, 2016
Thirty-four dinoflagellate cyst taxa were found in surface sediment (0–2 cm) at five stations (60... more Thirty-four dinoflagellate cyst taxa were found in surface sediment (0–2 cm) at five stations (60–100-m water depth) in the Gulf of Gemlik, Marmara Sea, during four seasons from August 2011 to May 2012. Lingulodinium machaerophorum, Operculodinium centrocarpum and Selenopemphix quanta dominated cyst assemblages in the polluted gulf, where nutrient-rich surface water was stratified during most seasons and bottom water was hypoxic. Twelve cyst taxa were incubated and produced motile cells that reproduced and survived 14–15 days. Highest cyst species number (33) occurred in summer; maximum number of cysts (living and empty) per cm3 wet sediment was in spring, with the annual range from 1520 (fall) to 108,000 (spring). Nine taxa (Brigantedinium simplex, L. machaerophorum, O. centrocarpum, S. quanta, Spiniferites mirabilis, Spiniferites ramosus, cysts of Alexandrium sp., Scrippsiella trifida and S. trochoidea) were found in all seasons at all stations. The harmful dinoflagellates L. machaerophorum and cysts of S. trochoidea and Alexandrium sp. were the most abundant species. The cyst of the toxic species, Cochlodinium sp., is reported for the first time from Turkey. Other HAB species included A. tamarense, Protoceratium reticulatum, Heterocapsa triquetra and Gymnodinium catenatum/nolleri. Relative abundance of potentially toxic dinoflagellates (74%–92% of total cysts cm3) was always higher than nontoxic species, and percentage abundance of cysts cm3 produced by autotrophs (19/34 total species) almost always exceeded those of heterotrophs. Although distributions of the resting cyst taxa were significantly influenced by surface temperature, dissolved oxygen and total water depth, surface salinity was the strongest predictor for cyst occurrences.
Estuarine, Coastal and Shelf Science, 2015
ABSTRACT cmf 776, cmf 776
Toxicon : official journal of the International Society on Toxinology, Jan 15, 2006
Accumulation of Nodularia spumigena toxins by Mytilus edulis was studied during laboratory and me... more Accumulation of Nodularia spumigena toxins by Mytilus edulis was studied during laboratory and mesocosm experiments in order to investigate the possible pathways of nodularin in mussels and calculate toxin budgets. Mussels were exposed to 0.2-15.6 microg nodularin l(-1), fed for up to 5 days with Nodularia cells from culture, or blooming in different nutrient-treated seawater. Toxin concentration was monitored with LC-ESI-MS. During different exposures, the amount of nodularin detected in mussels increased linearly with increasing toxin concentration in food and attained 0.28-13.8 microg of nodularin g dw(-1) of the mussel whole body tissue after 12 h. The digestive gland was found to be the tissue with the highest toxin concentration. Nodularin concentration in faeces was not proportional to faeces production or to toxin concentration in food; however, it seemed to be mostly related to food quality as well as to food availability. The percentage of nodularin taken up by the mussels...
Eutrophication in Planktonic Ecosystems: Food Web Dynamics and Elemental Cycling, 1998
Abstract A mesocosm experiment was conducted in order to studythe structure of the planktonic foo... more Abstract A mesocosm experiment was conducted in order to studythe structure of the planktonic food web. The dynamicsof pico-, nano-and microplankton populations werefollowed during 40 days in four large (40 m 3) enclosures. In three tanks a gradient of ...
Harmful Algae, 2008
... Taleb et al. (2001) reported that clams accumulate PSP toxins to a lesser degree than other s... more ... Taleb et al. (2001) reported that clams accumulate PSP toxins to a lesser degree than other species; however, members of the family Veneridae can become very toxic by accumulating other toxins such as domoic acid (Vale and Sampayo, 2001). ...
Continental Shelf Research
Abstract The abundance of Transparent Exopolymer Particles (TEP) was determined on a seasonal bas... more Abstract The abundance of Transparent Exopolymer Particles (TEP) was determined on a seasonal basis (autumn, spring and summer) along a north-south transect in the NE Aegean Sea and the vicinity of the Dardanelles Straits. Their distribution patterns were studied in respect to hydrographic conditions and water mass characteristics in the area, as well as particulate organic carbon (POC) concentrations, changes in standing stocks of chlorophyll-α and bacterial production. TEP concentrations ranged from 15.4 to 188 µg GX eq L-1. Their spatial distribution patterns within the euphotic zone displayed significant seasonal variability, which appears to closely reflect the temporal variation of the water column structure, resulting from the encounter and interplay of the Black Sea and Levantine Water masses, and the associated biogeochemical processes. Minimum TEP concentrations during autumn could be likely attributed to a minor quantity of TEP and/or its dissolved precursors exuded by phytoplankton and their enhanced degradation due to their long residence time in the water column. During spring, high TEP production was mediated by actively growing phytoplankton, while during summer a positive link to the intense stratification of the water column and the enhanced bacterial growth within the Black Sea Water layer was observed. The results reported in this study highlight the fact that TEP carbon represents a significant fraction of the POC pool. Moreover, TEP production is critical in promoting particle coagulation rates, playing an important role in carbon cycling/transportation out of the euphotic zone.
Estuarine, Coastal and Shelf Science
Harmful algae, 2018
The marine dinoflagellate Azadinium poporum produce azaspiracids (AZA) and has been recorded wide... more The marine dinoflagellate Azadinium poporum produce azaspiracids (AZA) and has been recorded widely in the world. However, information on its biogeography is still limited, especially in view of the fact that A. poporum comprises several genetically differentiated groups. A total of 18 strains of A. poporum were obtained from the Eastern Mediterranean area by incubating surface sediment collected from Ionian Sea of Greece. The morphology of these strains was examined with light microscopy and scanning electron microscopy. Small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from all cultured strains. Molecular phylogeny based on concatenated SSU, LSU and ITS sequences confirmed three ribotypes within A. poporum and revealed two subclades within ribotypes A and C. Greek strains of A. poporum ribotype A were nested within ribotype A2 together with strains from Western Mediterranean Sea and French A...
Frontiers in Marine Science
Tsagaraki et al. Deposition Effects on E. Mediterranean Plankton Communities and increase in temp... more Tsagaraki et al. Deposition Effects on E. Mediterranean Plankton Communities and increase in temperature, which can lead to more persistent changes in plankton community structure. Here we demonstrate how a single dust deposition event leads to enhancement of phytoplankton and microzooplankton and can eventually, through copepods, transport more nutrients up the food web in the Eastern Mediterranean Sea.
Frontiers in Marine Science
The effect of episodicity of Saharan dust deposition on the pelagic microbial food web was studie... more The effect of episodicity of Saharan dust deposition on the pelagic microbial food web was studied in the oligotrophic Eastern Mediterranean by means of a mesocosm experiment in May 2014. Two different treatments in triplicates (addition of natural Saharan dust in a single-strong pulse or in three smaller consecutive doses of the same total quantity), and three unamended controls were employed; chemical and biological parameters were measured during a 10-day experiment. Temporal changes in primary (PP) and bacterial (BP) production, chlorophyll a (Chl a) concentration and heterotrophic bacteria, Synechococcus and mesozooplankton abundance were studied. The results suggested that the auto-and hetero-trophic components of the food web (at least the prokaryotes) were enhanced by the dust addition (and by the nitrogen and phosphorus added through dust). Furthermore, a 1-day delay was observed for PP, BP, and Chl a increases when dust was added in three daily doses; however, the maximal values attained were similar in the two treatments. Although, the effect was evident in the first osmotrophic level (phytoplankton and bacteria), it was lost further up the food web, masked under the impact of grazing exerted by predators such as heterotrophic flagellates, ciliates and dinoflagellates. This was partly proved by two dilution experiments. This study demonstrates the important role of atmospheric deposition and protist grazing when evaluating the effect on oligotrophic systems characterized by increased numbers of trophic levels.
Frontiers in Marine Science, 2017
Frontiers in Marine Science, 2017
The impact of viral lysis and grazing by flagellates on bacterioplankton production was assessed ... more The impact of viral lysis and grazing by flagellates on bacterioplankton production was assessed during a mesocosm experiment in the Eastern Mediterranean Sea, in response to Saharan dust (SD) vs. mixed aerosols (A) addition. The results highlight a positive effect on bacterial abundance, production and growth rate (∼1.2, ∼2.4, and ∼1.9-fold higher than the controls) in both SD and A, which was also confirmed by the increased portion of high DNA content bacteria (up to 48% of the bacterial community). Lytic viral production and the portion of bacterial production lost due to viral lysis were lower in SD and A after dust addition than in the controls (0.33 ± 0.17 × 10 6 virus-like particles mL −1 h −1 and 6 ± 4%, respectively). Potential ingestion rate of bacteria by flagellates increased upon dust enrichment, but did not differ between mesocosms. Larger predators possibly down regulated flagellate abundance, and the calculated portion of bacterial production lost due to flagellate grazing was probably an artifact. Higher frequency of lysogenic cells in A compared to SD and the controls four days after dust addition may reflect faster phosphorus limitation in A, due to receiving less dissolved inorganic phosphorus and more dissolved inorganic nitrogen than SD.
Frontiers in Marine Science, 2016
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Frontiers in Marine Science, 2016
composition than did that of SD. Our findings show that episodic atmospheric deposition events mi... more composition than did that of SD. Our findings show that episodic atmospheric deposition events might affect the microbial community with regards to their abundance, activity and composition over a short period of time, and thus regulate the function of the microbial community and carbon cycling in oligotrophic waters.
Frontiers in Marine Science, 2016
Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., ... more Large amounts of dust and atmospheric aerosols, originating from surrounding desert areas (e.g., Sahara and Middle East) are deposited annually on the surface of the Eastern Mediterranean Sea. These depositions can provide high amounts of micro (such as Fe, Zn, Co) and macro nutrients (such as P and N) to supplement nutrient-poor surface waters-that typically limit primary productivity and also dinitrogen (N 2) fixation in many marine environments. Here, we studied the impact of the atmospheric deposition of dust and aerosols on N 2 fixation in the Cretan Sea (Eastern Mediterranean Sea). Mixed polluted aerosols (hereafter A) and Saharan dust (hereafter SD) were added to nine mesocosms (3-m 3 each) containing surface mixed layer seawater (∼10 m), and N 2 fixation was evaluated for 6 days during May 2012 (springtime). The addition of SD triggered a rapid (30 h) and robust (2-4-fold) increase in N 2 fixation rates that remained high for 6 days and contributed 3-8% of the primary productivity. The A addition also resulted in higher N 2 fixation rates compared to the unamended control mesocosms, although the responses were less profound (1.5-2-fold) and accounted for only 2-4% of the primary productivity. The microbial community responded differently to the two additions. Heterotrophic bacterial N 2 fixers dominated the diazotroph community in A and the control mesocosms, while the non-filamentous cyanobacterial group Trichodesmium prevailed in the SD treatment (68% of all the operational taxonomic units, verified by qPCR analyses). Our results indicate that the aerosol source, its route prior to deposition, and its specific chemical composition, can alter the diazotrophic diversity and activity in the Eastern Mediterranean Sea and may thus impact both the N and C dynamics in this impoverished environment.
Mediterranean Marine Science, 2014
Τhe entire pelagic microbial food web was studied during the winter-spring period in the frontal ... more Τhe entire pelagic microbial food web was studied during the winter-spring period in the frontal area of the North Aegean Sea. Abundance of viruses, heterotrophic bacteria, cyanobacteria, auto- and hetero-trophic flagellates, and ciliates, as well as bacterial production, were measured at three stations (MD1, MD2, MD3) situated along a N-S transect between the area directly influenced by the inflowing Black Sea water and the area covered by the Levantine water. Samples were collected in December 2009, and January, March, April, and May 2011. Station MD1 exhibited the highest values of abundance and integrated biomass of all microbial groups and bacterial production during all months, and MD3 the lowest. Bacteria dominated the total integrated biomass at all stations and months, followed by cyanobacteria, auto-, hetero-trophic flagellates and ciliates. On a temporal scale, the microbial food web was less important in March as all microbial parameters at all stations showed the lowest...
Frontiers in Marine Science, 2016
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Estuarine, Coastal and Shelf Science, 2016
Phycologia, 2016
Thirty-four dinoflagellate cyst taxa were found in surface sediment (0–2 cm) at five stations (60... more Thirty-four dinoflagellate cyst taxa were found in surface sediment (0–2 cm) at five stations (60–100-m water depth) in the Gulf of Gemlik, Marmara Sea, during four seasons from August 2011 to May 2012. Lingulodinium machaerophorum, Operculodinium centrocarpum and Selenopemphix quanta dominated cyst assemblages in the polluted gulf, where nutrient-rich surface water was stratified during most seasons and bottom water was hypoxic. Twelve cyst taxa were incubated and produced motile cells that reproduced and survived 14–15 days. Highest cyst species number (33) occurred in summer; maximum number of cysts (living and empty) per cm3 wet sediment was in spring, with the annual range from 1520 (fall) to 108,000 (spring). Nine taxa (Brigantedinium simplex, L. machaerophorum, O. centrocarpum, S. quanta, Spiniferites mirabilis, Spiniferites ramosus, cysts of Alexandrium sp., Scrippsiella trifida and S. trochoidea) were found in all seasons at all stations. The harmful dinoflagellates L. machaerophorum and cysts of S. trochoidea and Alexandrium sp. were the most abundant species. The cyst of the toxic species, Cochlodinium sp., is reported for the first time from Turkey. Other HAB species included A. tamarense, Protoceratium reticulatum, Heterocapsa triquetra and Gymnodinium catenatum/nolleri. Relative abundance of potentially toxic dinoflagellates (74%–92% of total cysts cm3) was always higher than nontoxic species, and percentage abundance of cysts cm3 produced by autotrophs (19/34 total species) almost always exceeded those of heterotrophs. Although distributions of the resting cyst taxa were significantly influenced by surface temperature, dissolved oxygen and total water depth, surface salinity was the strongest predictor for cyst occurrences.
Estuarine, Coastal and Shelf Science, 2015
ABSTRACT cmf 776, cmf 776
Toxicon : official journal of the International Society on Toxinology, Jan 15, 2006
Accumulation of Nodularia spumigena toxins by Mytilus edulis was studied during laboratory and me... more Accumulation of Nodularia spumigena toxins by Mytilus edulis was studied during laboratory and mesocosm experiments in order to investigate the possible pathways of nodularin in mussels and calculate toxin budgets. Mussels were exposed to 0.2-15.6 microg nodularin l(-1), fed for up to 5 days with Nodularia cells from culture, or blooming in different nutrient-treated seawater. Toxin concentration was monitored with LC-ESI-MS. During different exposures, the amount of nodularin detected in mussels increased linearly with increasing toxin concentration in food and attained 0.28-13.8 microg of nodularin g dw(-1) of the mussel whole body tissue after 12 h. The digestive gland was found to be the tissue with the highest toxin concentration. Nodularin concentration in faeces was not proportional to faeces production or to toxin concentration in food; however, it seemed to be mostly related to food quality as well as to food availability. The percentage of nodularin taken up by the mussels...
Eutrophication in Planktonic Ecosystems: Food Web Dynamics and Elemental Cycling, 1998
Abstract A mesocosm experiment was conducted in order to studythe structure of the planktonic foo... more Abstract A mesocosm experiment was conducted in order to studythe structure of the planktonic food web. The dynamicsof pico-, nano-and microplankton populations werefollowed during 40 days in four large (40 m 3) enclosures. In three tanks a gradient of ...