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Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-05-22T16:43:23Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Magalhães, G.M.O. Tese versão final.pdf: 1681761 bytes, checksum: 993b74d48394c8fed037a308d0cd9586 (MD5) / Made available in DSpace on 2017-05-22T16:43:23Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Magalhães, G.M.O. Tese versão final.pdf: 1681761 bytes, checksum: 993b74d48394c8fed037a308d0cd9586 (MD5) Previous issue date: 2014 / A presente tese teve como objetivo geral conhecer como a produtividade de Copepoda é afetada pelo grau de poluição em estuários. Para a estimativa da produtividade de Copepoda foram usadas regressões comprimento-peso para as principais espécies de Copepoda e foram utilizadas equações disponíveis na literatura para conversão de sua biomassa em produtividade secundária. Para acessar a massa d’água dominante foram obtidos dados de temperatura e salinidade e para obter informações sobre o grau de poluição foram medidos o oxigênio dissolvido e a clorofila-a. As amostras foram coletadas em uma estação fixa na Bacia do Pina, em marés de sizígia e quadratura com redes de plâncton com 64 e 200 μm de abertura de malha, através de arrastos horizontais superficiais. Foi também coletado sedimento para o cultivo em laboratório de cistos de resistência inseridos no mesmo, e importantes para uma possível recolonização de ambientes após períodos adversos, representando fonte potencial para o recrutamento de náuplios na coluna d’água. As maiores profundidades ocorreram durante as preamares de sizígia, com máximo de 2,50 m. A temperatura da água apresentou valores variando entre 26 e 31° C e a salinidade entre 26 e 37, evidenciando estuário variando de polihalino a euhalino. O oxigênio dissolvido indicou área poluída na baixa-mar com cerca de 40% de saturação, sendo esta poluição reduzida durante as preamares quando chega a mais de 100% de saturação. A clorofila-a apresentou altas concentrações com maiores valores médios na maré de quadratura (20 mL.L-1 ) em relação a sizígia (6 mL.L-1 ). O zooplâncton esteve representado por 44 taxa pertencentes aos clados Rotifera, Ciliophora, Foraminífera, Cnidaria, Mollusca, Bryozoa, Annelida, Arthropoda, Chaetognatha e Chordata. Copepoda destacou-se com 18 espécies, entre as quais foram frequentes e abundantes nas duas frações estudadas Oithona oswaldocruzi, O. hebes, Dioithona oculata, Parvocalanus crassirostris, Acartia lilljeborgi, Temora turbinata e Euterpina acutifrons. Este grupo caracteriza os estuários tropicais brasileiros. A densidade média mínima de Copepoda foi de 3420 ± 1906 ind.m-3 na maré de sizígia na fração do mesozooplâncton e o máximo foi de 80528 ± 51246 ind.m-3 na maré de quadratura na fração do microzooplâncton. Em termos gerais, a densidade de Copepoda na fração do microzooplâncton foi mais de 10 vezes a quantidade da fração do mesozooplâncton; na maré de quadratura, essa fração foi cerca de 3 vezes mais densa do que a encontrada na sizígia e cerca de 1,5 vezes mais que na fração do mesozooplâncton. Para as estimativas de produção foram consideradas: Oithona oswaldocruzi, O. hebes, D. oculata, Acartia lilljeborgi e Parvocalanus crassirostris, que juntas totalizaram mais de 60% de toda comunidade. Em termos de produção total, as taxas mais altas ocorreram durante a quadratura (10,07 mgC m -3 dia-1 , para a comunidade do microzooplâncton; e 6,1 mgC m -3 dia-1 , para o mesozooplâncton). Embora esse ecossistema estuarino apresente alto grau de poluição nas baixamares de quadratura, a mesma é amenizada pela grande penetração do fluxo marinho, apresentando o ambiente uma melhor qualidade nas preamares de sizígia. As taxas mais elevadas de produção no período de maior poluição mostram a grande resiliência das espécies estudadas de Copepoda aos impactos antropogênicos, contudo quando comparado a estuários similares observou-se, que a produção é reduzida pela forte poluição. / The present thesis aims to assess how the productivity of Copepods is affected by the degree of pollution in estuaries. For the estimation of productivity of Copepoda it was used length-weight regressions for the main species of Copepoda and equations available in the literature were used for conversion of biomass in secondary productivity. To access the dominant water mass it was measured temperature and salinity; and to access the pollution degree it was measured the dissolved oxygen and chlorophyll-a. The samples were collected in a fixed station in the Bacia do Pina in spring and neap tides using plankton nets with 64 and 200 μm mesh size, through horizontal surface hauls. It was also collected sediment for cultivation of resistance cysts in laboratory, important for testing a possible recolonization after adverse periods, representing the cysts potential source for the recruitment of nauplii in the water column. The greater depths occurred during spring high tides, with maximum of 2.50 m. The water temperature presented values varying between 26 and 31oC and salinity from 26 to 37, characterizing the estuary with a polihaline to euhaline regime. Dissolved oxygen indicated polluted area at low tide with about 40% of saturation, this pollution being reduced during the high tides when O2 attain more than 100% saturation. Chlorophyll-a presented high concentrations, with higher average values during neap tide (20 mL L-1 ) in relation to spring tide (6 mL L-1 ). The zooplankton was represented by 44 taxa belonging to clades Rotifera, Ciliophora, Foraminifera, Cnidaria, Mollusca, Bryozoa, Annelida, Arthropoda, Chaetognatha and Chordata. Copepoda outranked with 18 species, among them were frequent and abundant in the two net fractions studied Oithona oswaldocruzi, O. hebes, Dioithona oculata, Parvocalanus crassirostris, Acartia lilljeborgi, Temora turbinata and Euterpina acutifrons. This group characterizes the Brazilian tropical estuaries. The average minimum density of Copepods was 3420 ± 1906 ind.m-3 at spring tide in mesozooplankton fraction, and the maximum was 80528 ± 51246 ind.m-3 at neap tide in the microzooplankton net fraction. In general, the density of Copepoda in the fraction of microzooplankton was more than 10 times the amount of the fraction of the mesozooplankton; and neap tide was about 3 times more dense than spring tide for the fraction of the microzooplankton and about 1.5 times the amount of the fraction of the mesozooplankton. For production estimates were considered: Oithona oswaldocruzi, O. hebes, D. oculata, Acartia lilljeborgi and Parvocalanus crassirostris which together totaled more than 60% of the whole community. In terms of total production, the highest rates occurred during the neap tide (10.07 mgC m -3 dia-1 to the copepods in the microzooplankton, and 6.1 mgC m -3 dia-1 to the mesozooplankton fraction). Although this estuarine ecosystem present high degree of pollution during neap low tides, this pollution is ameliorated by the large penetration of the marine flow presented the environment a better quality during spring high tide. The higher production in the period of greatest pollution shows the great resilience of these Copepoda to anthropogenic impacts, however this production when compared to others similar estuaries has been reduced by pollution.

A partir de la hipótesis de que las especies del mesozoo-plancton del estuario de Bahía Blanca muestran patrones de distribución y abundancia en la columna de agua que están relacionados con el ciclo día/noche, la marea y las variables fisicoquímicas, se propuso estudiar la influencia del ciclo diur-no y los diferentes estados de la marea en la estructura trófi-ca del mesozooplancton. Para ello se analizó la abundancia y composición específica del mesozooplancton a diferentes pro-fundidades en la columna de agua a lo largo de dos ciclos de marea para cada estación del año. Se midieron distintas varia-bles físicoquímicas con el objetivo de relacionarlas con el perfil vertical del mesozooplancton. Se estudió el comportamiento y la abundancia de las especies del mesozooplancton durante un mes lunar completo y se describieron las interacciones di-námicas de la estructura trófica del mesozooplancton. Se identificaron 54 taxa y se observó una mayor abundancia y diversidad de especies en el fondo. El mesozooplanctón estu-vo dominado por los copépodos Acartia tonsa, Paracalanus parvus, Eurytemora americana y las larvas de Balanus spp, marcando la tendencia anual del mesozooplancton total. A. tonsa se presentó durante todo el ciclo anual, mientras que E. americana se la encontró en otoño-invierno. Las mayores sali-nidades y menores temperaturas resultaron favorables para las especies más abundantes del estuario (Acartia tonsa, Pa-racalanus parvus, Eurytemora americana) y fueron desenca-denantes de respuestas internas como ser el incremento en la actividad natatoria para otras especies (Neohelice granulata, Cyrtograpsus altimanus). La marea en estado de flujo y plea-mar fue favorable para especies que aumentaron sus abundan-cias en estos períodos tanto en superficie como en el fondo. Ejerció un efecto importante sobre la advección de larvas de decápodos (N. granulata y C. altimanus), manifestándose du-rante los períodos de flujo y reflujo. Por otro lado, se pudo observar que los copépodos A. tonsa, P. parvus, L. fluviatilis y E. acutifrons permanecieron en el fondo donde las corrientes son menores debido a la fricción. Los vientos tuvieron una influencia importante sobre la distribución de los organismos. En situaciones de calma con predominio de viento N se obser-vó un aumento de abundancia en superficie del mesozoo-plancton total. Por otro lado, durante los períodos de mayor intensidad y cambio de dirección del viento las abundancias aumentaron en el fondo. La radiación solar reguló la posición en la columna de agua de larvas de cangrejos y adultos de misidáceos. Se observó un mayor número de individuos en su-perficie durante horas de oscuridad en tanto que aumentaron su abundancia en el fondo durante horas del día. Para el ciclo lunar las máximas abundancias se dieron en las fases de ma-yor luminosidad y en superficie. La influencia del ciclo de la luna sobre el mesozooplancton es un fenómeno que está rela-cionado directamente con la predación, ya que esta ocurre más eficientemente en luna llena. La comunidad del meso-zooplancton está principalmente compuesta por omnívoros y herbívoros. En primavera-verano, los omnívoros fueron el nivel trófico más abundante, lo que está altamente relacionado con las importantes abundancias de A. tonsa. En otoño-invierno el nivel trófico dominante fue el de los herbívoros+detritívoros que presentan altas abundancias en el fondo durante las ho-ras del día y en superficie en la oscuridad. Como conclusión, uno de los resultados más importantes de esta tesis es que un número significativo de especies presentaron altas densi-dades en superficie durante las horas de oscuridad y en el fondo durante las horas del día. Esto estaría corroborando que muchas de ellas realizarían un desplazamiento vertical. Ade-más, el elevado número de especies capturadas en el fondo, reforzaría la hipótesis que un número significativo de especies presentarían un comportamiento rítmico sincronizado con las mareas. Esta tesis expone por primera vez para la zona inter-na del estuario de Bahía Blanca (Pto. Ing. White) los resul-tados de dicha interacción y la manera en que afectan los factores fisicoquímicos a la distribución de las especies del mesozooplancton a lo largo de dos ciclos de marea y de un mes lunar. / From the hypothesis that species of mesozooplankton of the Bahía Blanca estuary show patterns of distribution and abun-dance in the water column that are related with the day/night cycle, the tide and physicochemical variables, it was propo-sed to study the influence of the day cycle and the tide in the trophic structure of mesozooplankton. It was analyzed the abundance and species composition of mesozooplankton at different depths in the water column along two tidal cycles each season. Physicochemical variables were measured in order to relate them to the vertical distribution of mesozoo-plankton. It was studied the behavior and abundance of spe-cies of mesozooplankton during a full lunar month and descri-bed the dynamic interactions of the trophic structure of meso-zooplankton. There were identified 54 taxa and there was found greater abundance and species diversity in the deep. The mesozooplankton was dominated by the copepods Acartia tonsa, Paracalanus parvus, Eurytemora americana and the lar-vae of Balanus spp, controlling the annual fluctuation of total mesozooplankton. A. tonsa was observed during the annual cycle, while E. americana was found during autumn and win-ter. The higher salinities and lower temperatures were favo-rable for the most abundant species in the estuary (Acartia tonsa, Paracalanus parvus, Eurytemora americana) and were triggers of internal responses such as increasing in swimming activity for other species (Neohelice granulata, Cyrtograpsus altimanus). The flood and high tide were favorable for species that increased their abundances in these periods both in sur-face and deep. It exerted a significant effect on the advec-tion of decapods larvae (N. granulata and C. altimanus), mani-festing during ebb and flood. Furthermore, it was observed that the copepods A. tonsa, P. parvus, L. fluviatilis and E.acu-tifrons remained in the bottom where currents are lower due to friction. The winds were the major influence on the distribu-tion of organisms. During calm and primarily winds from N was observed an increase in surface abundance of total mesozoo-plankton. On the other hand, during periods of higher intensity and changes of wind direction there was an increase of abun-dances in the deep. Solar radiation regulated the position in the water column of crabs larvae and adults of mysids. There were a greater number of individuals on the surface during hours of darkness and increased in abundance in the bottom at daylight hours. During the lunar cycle the highest abundan-ces occurred in the phases of higher luminosity and at surface. The influence of lunar cycle on mesozooplankton was a pheno-menon that was directly related to predation, as it occurred more efficiently at full moon. The mesozooplankton community is mainly composed of omnivores and herbivores. In spring and summer, omnivores were the most abundant trophic level, which is highly related to the significant abundance of A. tonsa. In autumn and winter the dominant trophic level was the detritivores+herbivores with higher abundance in the bottom during daylight hours and in the surface at night. In conclusion, one of the most important results of this thesis is that a significant number of species had high densities on the surface during the darkness hours and in the bottom during daylight hours. This would validate that many of them would experience vertical movement. In addition, the higher number of species caught in the bottom supports the hypothesis that a significant number of species present a rhythmic behavior synchronized with the tides. This thesis presents the first results in the inner zone of the Bahía Blanca estuary (Ing. White Port) of this interaction and how the physicochemical variables affect the distribution of mesozooplankton species along two tidal cycles and a lunar month.

The sea louse (Lepeophtheirus salmonis), whose larvae are planktonic and disseminated in the water column, is an economically important parasite of Atlantic salmon (Salmo Salar). The effect of temperature (5, 10, 15°C), diet (larvae alone, larvae plus phytoplankton), and bivalve size (small, medium, large) on the amount of L. salmonis larvae ingested by various species of filter-feeding bivalves (Pacific oysters, Pacific scallops, blue/Gallo’s mussel hybrids, basket cockles) was examined in a series of laboratory experiments. Four separate temperature/diet experiments were conducted (one for each species) in which large bivalves were individually placed in 2-L containers holding 750 ml of aerated, filtered seawater and fed one of three treatment diets: (1) phytoplankton: ~7.1 x 104 cells ml-1 of Isochrysis sp. (Tahitian strain, TISO); (2) sea lice larvae: ~431 larvae (mostly nauplii); and (3) phytoplankton and larvae (at the levels mentioned above). There was also a control treatment of phytoplankton and larvae, but no bivalve. After feeding for 1 h, the bivalve soft tissues were excised and preserved, the digestive system was dissected, and sea lice larvae were removed and counted to provide direct evidence of ingestion. The larvae remaining free swimming in the container were iv preserved and counted. The proportion missing from the container was used to estimate ingested larvae in statistical analyses. Two additional experiments investigating the effect of bivalve size (small, medium, large) on the ingestion of sea lice larvae were conducted with Pacific oysters and Pacific scallops. The heights for oysters (anterior-posterior axes) were 19.2, 44.2, and 84.0 mm, and scallops (dorsal hinges to ventral margins) were 40.3, 64.1, 102.7 mm. The methodology for the size experiments was as previously described for the temperature/diet experiments with the following changes: (1) the diet of larvae alone was not used; (2) the mean number of larvae in each container was ~498; (3) the mean concentration of TISO added to each container was ~7.8 x104 cells ml-1, and (4) the mean water temperature was 10.4°C. The data for the four temperature/diet experiments indicate that all four bivalve species ingested sea lice larvae, whether their diet included phytoplankton or not, and that temperature had no significant effect. The data for the two size experiments indicated that all three sizes of oysters and scallops ingested sea lice larvae and that there was a significant size effect. Large shellfish consumed a significantly greater proportion of the sea lice larvae than the small shellfish. Bivalves grown at salmon net pens as part of an IMTA (Integrated Multi-Trophic Aquaculture) system may be able to reduce the number of sea lice larvae as well as being an additional crop of market value. Future research, conducted at a commercial scale at a salmon farm, is warranted in order to determine if bivalves can serve in this role. / Graduate

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-06-29T17:11:15Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2010-Dissertação-DéboraBarbosa.pdf: 1437104 bytes, checksum: c4ce02bf62658ef9c6ea3916255fe546 (MD5) / Made available in DSpace on 2017-06-29T17:11:15Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2010-Dissertação-DéboraBarbosa.pdf: 1437104 bytes, checksum: c4ce02bf62658ef9c6ea3916255fe546 (MD5) Previous issue date: 2010 / A composição do mesozooplâncton do estuário do rio Timbó, Paulista –PE foi analisada nos meses de julho, setembro e dezembro de 2009. Cada coleta teve duração de 24 horas, sendo realizados arrastos de 15 minutos a cada 3 horas, em duas estações fixas. As amostras foram obtidas através de rede de plâncton com 300 micrômetros de abertura de malha. Em cada coleta foram aferidas: temperatura, profundidade e salinidade. O material coletado foi fixado em formol a 4% e analisado posteriormente sob estereomicroscópio e microscópio óptico. A riqueza, diversidade e equitabilidade das comunidades mesozooplanctônicas e de copépodes foram analisadas através do ANOVA no programa STATISTICA 6.0 e a estrutura das comunidades analisada através do programa PRIMER 4.0. O mesozooplâncton do estuário do rio Timbó esteve representado por 39 táxons distribuídos em 08 filos, dentre os quais Arthropoda foi o mais representativo compondo 90,4% dos organismos, sendo Crustacea Copepoda o grupo dominante em todos os meses. Foram observadas diferenças significativas na estrutura das comunidades mesozooplanctônicas e de copépodes em relação às marés, meses do ano e localização ao longo do estuário, onde a maior diversidade e riqueza de organismos foram observadas na estação de coleta mais próxima do mar, nas marés cheias e enchente para o mesozooplâncton e nas marés cheia e vazante para Copepoda. O mês de dezembro apresentou densidades mais baixas de organismos porém maior diversidade. A comunidade mesozooplanctônica foi considerada típica de ambiente estuarinona qual o holoplâncton foi mais abundante que o meroplâncton em todos os meses, o que é esperado para regiões estuarinas. Dentre os copépodes,Acartia lilljeborgi foi aespécie mais frequentee abundante durante todo período, ressaltando-se ainda a ocorrência frequente de Acartia tonsae Pseudodiaptomus acutus. / The mesozooplankton composition of the Timbó River, Paulista-PE was analyzed in July, Septemberand December of 2009. The sampling lasted 24 hours, being realized tows of 15 minutes at every three hours at two fixed stations. Samples were obtained by plankton net with 300 μm mesh size. In each sampling weremeasured temperature, depth and salinity. The samples were fixed with formaldehyde at 4% and posteriorly analyzed under stereomicroscope and optical microscope. Therichness, diversity and equitability of the mesozooplankton and copepods community were analyzed using ANOVA of the STATISTICA 6.0 software, while the structure of the community was analyzed on the PRIMER 4.0 software. The mesozooplankton of the Timbó River was represented by 39 taxa, distributed in 8 phylum. The phylum Arthropoda was the most representative having 90,4% of the organisms. Copepods were the dominant group in all months. Significant differences were observed on the structure of the mesozooplankton and copepods community between tides, months and location along the estuary. The highest diversity and richness of organisms were observed in the sampling station closest to the sea, on the high and flood tides and for the mesozooplankton and on the flood and ebb tides for Copepoda. December presented the lowest density of organism although had the highest diversity. The mesozooplankton community was considered typical of a estuarine environment, in which the holoplankton was more abundant than the meroplankton in all months. This fact is expected for estuarine regions. Among the copepods, Acartia lilljeborgi wasmost frequent andabundant species during the whole period. It is worth mentioning the frequent occurrence of Acartia tonsaand Pseudodiaptomus acutus.

Beca JAE-Predoctoral CISC; Proyecto LARECO CTM2011-25929

Mesozooplankton are of critical importance to marine food webs by transferring energy from the microbial food web to higher trophic levels and depositing energy to the deeper ocean layers through fecal deposition. While decades of research have shown that viruses have significant impacts in the oceans, and infect a wide range of organisms from bacteria to whales, there is still little known about the impacts of viruses on the mesozooplankton community. As copepods are the most abundant mesozooplankton group, this study sought to characterize the viruses present in natural populations of the calanoid copepods Acartia tonsa and Labidocera aestiva in Tampa Bay, Florida. Viral metagenomics revealed two virus genomes, named Acartia tonsa copepod circovirus (AcCopCV) and Labidocera aestiva copepod circovirus (LaCopCV), which were discovered in their respective copepod species. Both viruses show amino-acid similarities to known circoviruses, and phylogenetic and genomic analyses suggest they may be divergent members of the Circoviridae family. LaCopCV was found to be extremely prevalent in the L. aestiva population, with up to 100% of individuals infected. High viral loads for LaCopCV were observed by quantitative PCR, with an average viral load of 1.3x105 copies per individual. In addition, transcription of the LaCopCV replication gene was detected in L. aestiva, demonstrating active viral replication. AcCopCV could be detected sporadically in A. tonsa populations throughout the year. The circoviruses were specific to their respective hosts, and were not detected in the other copepod species or surrounding seawater. Virus-like particles were observed in A. tonsa and L. aestiva under transmission electron microscopy, demonstrating that viruses were actively proliferating in copepod connective tissue, as opposed to gut tissue, parasites, or symbionts. Preliminary results from in-situ hybridization show that the AcCopCV genome can be detected in A. tonsa tissue, linking the discovered genomes to virus propagation in copepod tissue. This is the first study describing viruses in copepods, as well as the first discovery of circoviruses infecting marine organisms. These results suggest that viruses impact marine copepod populations, necessitating further studies to determine the ecological impacts of viruses on the mesozooplankton community.

Στόχο της παρούσας διατριβής αποτέλεσε η διερεύνηση των αβιοτικών και βιοτικών παραγόντων που ελέγχουν τη χωροχρονική κατανομή δύο βασικών συστατικών του πλαγκτικού συστήματος στο βορειοανατολικό Αιγαίο, του μεσοζωοπλαγκτού και των ιχθυονυμφών. Η περιοχή μελέτης παρουσιάζει ιδιαίτερο ενδιαφέρον καθώς χαρακτηρίζεται από αυξημένα επίπεδα παραγωγικότητας, συγκριτικά με τον ολιγότροφο χαρακτήρα της ανατολικής Μεσογείου, και ως εκ τούτου υψηλή συγκέντρωση ιχθυοαποθεμάτων (κυρίως μικρών πελαγικών ψαριών). Τα χαρακτηριστικά αυτά θεωρείται ότι σχετίζονται με την τοπογραφία της περιοχής (εκτεταμένη υφαλοκρηπίδα), την εισροή ποταμών αλλά κυρίως με την έντονη μέσης κλίμακας υδρολογική πολυπλοκότητα (μέτωπο Λήμνου, αντικυκλώνας Σαμοθράκης), που επάγει η εισροή και κυκλοφορία του χαμηλής αλατότητας νερού της Μαύρης Θάλασσας (<30 psu), στα 20-30 επιφανειακά μέτρα της υδάτινης στήλης. Η μελέτη της κατανομής και σύνθεσης του μεσοζωοπλαγκτού (σε κατακόρυφη και οριζόντια διάσταση) πραγματοποιήθηκε σε ένα εκτεταμένο δίκτυο σταθμών κατά τη διάρκεια τριών περιόδων θερμοστρωμάτωσης (Ιούλιος 2003– Σεπτέμβριος 2003 – Ιούλιος 2004), ενώ των ιχθυονυμφών κατά το μήνα Ιούνιο των ετών 2003 έως 2006. Σύμφωνα με τα αποτελέσματα της έρευνας, το απόθεμα του μεσοζωπλαγκτού στο Β.Α. Αιγαίο βρέθηκε μεγαλύτερο σε σχέση με εκείνο που αναφέρεται για άλλα ελληνικά πελαγικά νερά (Ιόνιο, νότιο Αιγαίο), κλειστούς και ημίκλειστους κόλπους καθώς και για ορισμένες παράκτιες και πελαγικές περιοχές της Δυτικής Μεσογείου. Σημαντικό κομμάτι της βιοκοινότητας, ειδικά στο επιφανειακό στρώμα επίδρασης του νερού της Μαύρης Θάλασσας, αποτέλεσαν ηθμοφάγες ομάδες όπως τα κλαδοκεραιωτά, οι κωπηλάτες και τα βυτιοειδή. Το Σεπτέμβριο 2003 η αλατότητα στην περιοχή βρέθηκε υψηλότερη κατά δύο μονάδες σε σχέση με τον Ιούλιο του ίδιου έτους, αντανακλώντας ενδεχομένως τη μικρότερη εισροή του νερού της Μαύρης Θάλασσας (πλούσιο σε διαλυτό οργανικό άνθρακα), και η αφθονία των ηθμοφάγων ομάδων ήταν σημαντικά μειωμένη την περίοδο αυτή σε σχέση με τον Ιούλιο 2003. Η χρονική αυτή διακύμανση στο απόθεμα του μεσοζωοπλαγκτού φάνηκε να σχετίζεται τόσο με τη διαφοροποίηση της επίδρασης του νερού της Μαύρης Θάλασσας στην περιοχή, όσο και με τα χαρακτηριστικά της βιολογίας των οργανισμών (π.χ. εποχικός κύκλος). Τον Ιούλιο 2004 το νερό της Μαύρης Θάλασσας περιορίστηκε κυρίως στο ανατολικό τμήμα της θρακικής υφαλοκρηπίδας, εγκλωβιζόμενο σε μια αντικυκλωνική δομή γύρω από τη Σαμοθράκη περίπου 50 km διαμέτρου, και οι τιμές αφθονίας και βιομάζας βρέθηκαν ιδιαίτερα αυξημένες (διπλάσιες έως και τριπλάσιες) συγκριτικά με το 2003. Σημαντικό παράγοντα διαφοροποίησης των ποσοτικών χαρακτηριστικών του μεσοζωοπλαγκτού (αφθονία & βιομάζα) αλλά και διαμόρφωσης διακριτών συναθροίσεων ειδών κωπηπόδων και κλαδοκεραιωτών αποτέλεσε το βάθος. Τα επιφανειακά νερά, που δέχονταν την άμεση επιρροή του νερού της Μαύρης Θάλασσας, εμφανίστηκαν περισσότερο παραγωγικά με ιδιαίτερη σύνθεση ειδών, των οποίων οι συναθροίσεις αποτέλεσαν ευαίσθητους δείκτες της οριζόντιας ωκεανογραφικής ετερογένειας. Αλλαγές στην παροχή και κυκλοφορία του νερού της Μαύρης Θάλασσας φάνηκε να προκαλούν μέσης κλίμακας υδρολογική (μέτωπα, στρόβιλοι) και βιολογική πολυπλοκότητα στην περιοχή, η οποία βρέθηκε να αντανακλάται περαιτέρω στη δομή και κατανομή των ζωοπλαγκτικών συναθροίσεων τόσο στο οριζόντιο επίπεδο όσο και στο κατακόρυφο. Συγκεκριμένα, τα υδρολογικά μέτωπα αποτέλεσαν περιοχές αυξημένων τιμών φθορισμού και μεσοζωοπλαγκτικής βιομάζας και ο αντικυκλώνας της Σαμοθράκης αποτέλεσε ιδιαίτερο βιογεωχημικό ενδιαίτημα, χαρακτηριζόμενο από αυξημένες τιμές συνολικής αφθονίας και ιδιαίτερη σύνθεση βιοκοινότητας μεσοζωοπλαγκτού. Εκτός από τη σημασία των φυσικών παραγόντων στην κατανομή του μεσοζωοπλαγκτού, βιολογικές αλληλεπιδράσεις, όπως ο ανταγωνισμός και η θήρευση φάνηκε επίσης να παίζουν σημαντικό ρόλο στη διαμόρφωση των παρατηρούμενων προτύπων κατανομής. Η χωρική ετερογένεια στην κατανομή των πληθυσμών του μεσοζωοπλαγκτού φάνηκε να αντικατοπτρίζει τη σημασία των οικοφυσιολογικών χαρακτηριστικών των ειδών και του εύρους μεγέθους των τροφικών σωματιδίων. Σε αντίθεση με το μεσοζωοπλαγκτόν, η μέση αφθονία του συνόλου των ιχθυονυμφών καθώς και των μεμονωμένων ταξινομικών κατηγοριών τους στην περιοχή του Β.Α. Αιγαίου κατά την διάρκεια της τετραετούς έρευνας (2003-2006), δεν παρουσίασε σημαντική χρονική διαφοροποίηση. Οι ιχθυονύμφες των επιπελαγικών ειδών αποτέλεσαν το σημαντικότερο συστατικό της βιοκοινότητας, με κυρίαρχο είδος το Engraulis encrasicolus (γαύρος), είδος του οποίου η κορύφωση ωοτοκίας συμπίπτει χρονικά με την περίοδο δειγματοληψίας. Η οριζόντια κατανομή των ιχθυονυμφών στην περιοχή ήταν ετερογενής και φάνηκε να ελέγχεται από τη συνεργιστική δράση παραμέτρων που επιδρούν στο απόθεμα των γεννητόρων καθώς και φυσικών και βιολογικών διαδικασιών που επιδρούν στη πλαγκτική φάση των απογόνων τους. Ιδιαίτερα σημαντικό ρόλο στη διαμόρφωση των παρατηρούμενων ιχθυονυμφικών προτύπων κατανομής βρέθηκε να παίζουν εξελικτικές προσαρμογές των ειδών σε μεγάλη κλίμακα χρόνου, όπως είναι η στρατηγική αναπαραγωγής και το περιβάλλον διαβίωσης. Ως εκ τούτου, το βάθος αλλά και ενδείξεις των τροφικών συνθηκών στην κολώνα του νερού (π.χ. συγκέντρωση ζωοπλαγκτού, φθορισμός) εξήγησαν σε σημαντικό βαθμό τη χωρική διαφοροποίηση της σύνθεσης της βιοκοινότητας των ιχθυονυμφών. Η κυκλοφορία επίσης του νερού της Μαύρης Θάλασσας φάνηκε σε πολλές περιπτώσεις να επηρεάζει σημαντικά τη διαμόρφωση της οριζόντιας κατανομής τους, είτε συμβάλλοντας στην κατακράτηση τους κοντά στα πεδία ωοτοκίας, ή, προκαλώντας τη διασπορά τους μακριά από αυτά. Η αντανάκλαση της οριζόντιας ωκεανογραφικής ετερογένειας στις συναθροίσεις των συγκεκριμένων μεροπλαγκτικών οργανισμών, παρότι λιγότερο έντονη σε σχέση με τις ολοπλαγκτικές ομάδες του μεσοζωοπλαγκτού, ήταν επίσης εμφανής. Η υψηλή συμμετοχή στη βιοκοινότητα των ιχθυονυμφών, πελαγικών ειδών, που κατά την ενήλικη φάση είναι άμεσα επηρεαζόμενα από μεταβολές που πραγματοποιούνται στο ανώτερο στρώμα της υδάτινης στήλης (όπου επιδρά το νερό της Μαύρης Θάλασσας), φαίνεται να είχε σημαντική συμβολή σε αυτό. / The main aim of the present study was directed towards an understanding of the agents (abiotic and biotic) that shape the spatiotemporal distribution patterns of two fundamental components of the northeastern Aegean Sea (NEA) planktonic food web, namely mesozooplankton and fish larvae. The study area is of great scientific interest due to its relatively increased local productivity levels, comparatively to the highly oligotrophic eastern Mediterranean, hence its importance as a fishing ground, especially for fisheries targeting small pelagic fish. These characteristics are considered to be associated with local topographic features (extended continental shelf), riverine inflow, but mainly the high hydrological complexity (development of fronts and eddies) which is induced by the inflow and advection of low salinity Black Sea waters (BSW) at the upper part of the water column (surface 20-30 m). Mesozooplankton group composition and distribution patterns were examined both in horizontal and vertical plane in an extended sampling grid, during three stratification periods (July 2003 – September 2003 – July 2004). Four broad scale ichthyoplankton surveys were carried out (June 2003, 2004, 2005, 2006) over a station grid similar to that of mesozooplankton sampling, in order to investigate the major distribution and abundance patterns of fish larvae in the area. According to this study, the overall mesozooplankton standing stock in the NEA was found higher than those typically reported for other Mediterranean ecosystems, including hellenic pelagic waters and various closed or semi-closed gulfs as wells as some western Mediterranean pelagic and coastal regions. During all sampling periods, filter feeding taxa i.e. cladocerans, doliolids, appendicularians consisted an important element of mesozooplankton group composition particularly at the upper water column (directly influenced by the BSW). In September 2003, when surface salinity was 2 psu higher than July 2003 (probably reflecting lower BSW inflow in the area), the abundance values of these zooplankters decreased considerably. This temporal variation seemed to be related not only to differentiation in BSW (rich in dissolved organic carbon) influence, but also to species specific biological characteristics (e.g. seasonal cycle). In July 2004, BSW circulation was mainly restricted in the eastern part of the Thracian shelf and the abundance and biomass values in the area were significantly increased (2-fold up to 3-fold increase) compared to the previous surveys. Sampling depth played an important role in the differentiation of quantitive mesozooplankton characteristics (in terms of abundance and biomass values) but also in the formation of different copepod and cladoceran species assemblages. Surface waters, under the direct influence of BSW, were more productive and their species assemblages were sensitive tracers of horizontal oceanographic variability. Changes in the supply and flow of BSW into the NEA induced mesoscale hydrographic (fronts, eddies) and biological variability which was reflected on the structure and distribution of mesozooplankton assemblages in the horizontal and vertical plane. Frontal zones (e.g. southeastern of Lemnos) were characterized by increased fluorescence values and mesozooplankton biomass. The anticyclonic eddy over the Thracian shelf, where BSW is entrapped (Samothraki gyre), seemed to serve as a distinguished biochemical habitat with increased mesozooplankton abundance values and distinctive group composition. Besides the importance of physical parameters for zooplankton distribution in the NEA, biological interactions (e.g. competition, predation) may have played a significant role in shaping the observed distribution patterns. The hydrological heterogeneity induced by the advection of the BSW seemed to influence the qualitative and quantitative characteristics of the lower trophic levels. In turn, mesozooplankton populations presented spatial heterogeneity that reflected the importance of food size spectra and species-specific ecophysiological characteristics. Contrary to mesozooplankton community, mean abundance values of fish larvae (either as a total or for each separate taxonomic category) did not show any significant interannual difference during the four year study in the area of NEA (2003-2006). Fish larvae of epipelagic species consisted the major component of community, while a dominance of anchovy larvae was also observed due to the coincidence of the sampling period with the intensive spawning of this species. Fish larvae horizontal distribution was heterogenous and seemed to be controlled by the coupling between agents acting on the spawning stock and physical and biological processes influencing the planktonic phase of their offsprings. Fish larvae distributional patterns seemed to highly depend on species specific evolutionary adaptations, like reproduction strategy and the living habitat of the adults. Sampling depth as well as indications of water column trophic conditions (e.g. zooplankton concentration, fluorescence), explained significantly the spatial differentiation of fish larvae assemblages during all sampling periods. The circulation pattern of BSW seemed to be an important determinant of the taxonomic composition and abundance of larval fish assemblages, contributing either on larval retention near the spawning grounds, or inducing their dispersion. The assemblages of these meroplanktonic early-life stages also reflected the horizontal oceanographic heterogeneity in NEA, though less intensively comparing to other holoplanktonic zooplankters. The domination of local larval fish community by larvae of pelagic fish, that in the adult phase are directly influenced by changes taking place in the upper part of the water column (influenced by the BSW), may have contributed to this reflection.

Οι κρατήρες διαφυγής ρευστών (pockmarks) είναι βυθίσματα σε μαλακά ιζήματα του βυθού, στα παράκτια και πελαγικά οικοσυστήματα. Μελετώνται παγκοσμίως τις τελευταίες τέσσερις δεκαετίες και στον ελληνικό χώρο έχουν εντοπιστεί κυρίως στη Δυτική Ελλάδα. Εξ αυτών, οι περισσότεροι είναι κρατήρες μεθανίου και μόνο στον Ελαιώνα Αιγίου και στον όρμο του Πρίνου έχουν βρεθεί κρατήρες γλυκού νερού. Έως τώρα, η μελέτη της βιολογίας των κρατήρων έχει εστιάσει κυρίως την περίπτωση των κρατήρων μεθανίου. Για τους κρατήρες γλυκού νερού δεν υπάρχουν εργασίες σχετικά με τη βιολογία τους, εκτός από μια η οποία αφορά τη μικροβιακή δράση στο ίζημα. Στον Ελαιώνα οπτική παρατήρηση έδειξε την ύπαρξη πληθώρας βενθικών οργανισμών, οι οποίοι απουσιάζουν από τον ευρύτερο πυθμένα. Το φαινόμενο αυτό έχει παρατηρηθεί σε πολλούς κρατήρες παγκοσμίως και θεωρείται ότι σχετίζεται κυρίως με τη φύση του υποστρώματος στο εσωτερικό της δομής των κρατήρων. Γενικά, υπάρχει πολύ περιορισμένη πληροφορία για το αβιοτικό και βιοτικό περιβάλλον των κρατήρων, ιδιαίτερα στη στήλη του νερού, ενώ δεν είναι σαφές το αν οι δομές αυτές μπορούν να αποτελέσουν διαταραγμένα περιβάλλοντα ή οάσεις οργανισμών. Η παρούσα εργασία διερευνά το πλαγκτικό στοιχείο στους κρατήρες γλυκού νερού του Ελαιώνα και αποτελεί την πρώτη σχετική αναφορά σε διεθνές επίπεδο, τουλάχιστον σε ότι σχετίζεται με το ζωοπλαγκτόν. Για τη μελέτη συλλέχθηκε μικρο- και μεσοζωοπλαγκτόν, έτσι ώστε να διερευνηθεί όλο το εύρος μεγέθους των οργανισμών από 50 μm έως 20 mm. Οι κρατήρες που μελετήθηκαν παρουσίασαν μικρή εκροή γλυκού νερού. Μετρήσεις θρεπτικών ιόντων και χλωροφύλλης -α έδειξαν ότι οι κρατήρες δεν επηρέασαν φυσικοχημικά το θαλάσσιο περιβάλλον. Ωστόσο, παρατηρήθηκε αύξηση της Chl-a κοντά στο στόμιο του κρατήρα και της φαιοφυτίνης (προϊόν αποδόμησης της Chl-a) και των θρεπτικών στο εσωτερικό του κρατήρα. Ως προς το ζωοπλαγκτόν, οι κρατήρες βρέθηκαν να συγκεντρώνουν μεγαλύτερες αφθονίες πελαγικών προνυμφών βενθικών οργανισμών που εγκαθίστανται στο εσωτερικό τους, όπως έχει επιβεβαιωθεί με οπτική παρατήρηση, καθώς και ειδών Αρπακτικοειδών και Ποικιλοστοματοειδών Κωπηπόδων (ενηλίκων, κωπηποδιτών, ναυπλίων). Τα εν λόγω κωπήποδα πιθανόν να σχετίζονται με την παρουσία αυξημένου αιωρούμενου οργανικού υλικού στους κρατήρες και ζελατινοειδών διηθηματοφάγων οργανισμών (κωπηλατών, βυτιοειδών) σε αυτούς. Επιπλέον, η αυξημένη συγκέντρωση ναυπλίων και κωπηποδιτικών σταδίων υποθέτουμε ότι μπορεί να σχετίζεται με την αυξημένη παρουσία αυγών κωπηπόδων, εφόσον η δομή του κρατήρα μπορεί να τα συγκεντρώνει. Επειδή η παρούσα μελέτη πραγματοποιήθηκε σε μια περίοδο ανάμιξης του νερού και μια περίοδο ασθενούς θερμοστρωμάτωσης, θεωρούμε ότι οι παρατηρήσεις μας για το ζωοπλαγκτόν δεν εμφανίζουν έντονο ‘’σήμα’’ και προτείνεται επανάληψη της έρευνας σε περίοδο έντονης θερμοστρωμάτωσης. / Pockmarks are seabed depressions on soft sediments, found in coastal and pelagic ecosystems. They have been studied for the last four decades and in Greece they can be found mainly in the western parts of the country. Most of the pockmarks are methane formatted, while groundwater formatted pockmarks have been found in Greece only in Elaionas bay and Prinos bay. So far, only methane pockmarks have been studied, concerning their biological components, and there are no references for the groundwater formatted ones, except one that focused on the microbial activity in the sediments. In Elaionas bay optical observations revealed the presence of an extensive benthic community that lacks from the surrounding seabed. This has been observed in a number of pockmarks worldwide and is believed to be co occurring with the presence of hard substrates in the pockmarks. Generally, there is little information of the biotic and abiotic environment of the pockmarks, especially in the water column, while it is not yet clear if these depressions should be considered as disturbed environments or local oasis for the organisms in the area. This study is focusing on the planktonic component of the pockmark field at Elaionas bay and to our knowledge it is the first attempt internationally, at least when it comes to zooplankton. Mesozooplankton and microzooplankton samples were collected in order to investigate the whole basic size range of the zooplankton community (50 μm to 20 mm). The studied pockmarks exhibited slight groundwater flow. Nutrient and chlorophyll a concentrations showed no physicochemical ‘’signal’’ in the pockmarks. However, there was a trend of increase of Chl –a near the opening of the pockmark and of phaeophytin and nutrients inside the pockmark. As for zooplankton, there is evidence that greater abundances of pelagic larvae of benthic organisms are concentrated in the pockmarks (the presence of the adults has been confirmed by divers and ROV), as well as some species of the Order Harpacticoida and Poecilostomatoida (adults, copepodites, nauplii). These copepods may be related to the increase of dissolved organic matter in the pockmark and the presence of tunicates (appendicularians, doliolids) also found concentrated in the pockmarks. Increased abundance of nauplii and copepodite stages in the pockmark is believed to result from the increase of copepod eggs, assuming that the pockmark can gather and retain them. Repetition of the sampling procedure at the pockmark field on a different season is necessary, because the lack of a strong thermocline suggests that any strong differences between the pockmark and the surrounding environment are being less detectible.