Gelatinous zooplankton are characterised as different from other planktonic taxa due to the high relative water content of their tissues. This thesis investigates whether elevated somatic water content (expressed here as carbon percentage) has effects on the biology of zooplankton. My approach was to examine this at a range of scales with a variety of approaches, ranging from experiments on individual ephyra larvae of Aurelia aurita, through analysis of a zooplankton time series at the Plymouth L4 station, up to a large scale meta-analysis of zooplankton growth and body composition data. In this meta-analysis, carbon percentage varied continuously across the range of the zooplankton, ranging from 0.01% to 19.02% of wet mass, a difference of over three orders of magnitude. Specific growth rate (g, d-1) was negatively related to carbon percentage, both across the full range of zooplankton species, and within the subset of taxa traditionally classified as gelatinous. The addition of carbon percentage to models of zooplankton growth rate based on carbon mass alone doubled explanatory power. I present an empirical equation of maximum (food saturated) zooplankton growth that incorporates carbon mass and carbon as a percentage of wet mass. Applying this equation to a natural assemblage near Plymouth yielded sometimes double the secondary production, as compared to a simpler model based on crustacean growth. Both interspecifically and intraspecifically, carbon percentage was negatively related to carbon mass; more gelatinous taxa tended to have higher carbon masses. During the early development of Aurelia aurita ephyrae, carbon percentage was found to decrease from 2.36% (an intermediate value between crustaceans and classical gelatinous zooplankton) down to 0.1%, the adult value for Aurelia aurita. Juvenile forms of gelatinous taxa are often poorly sampled and their intermediate carbon percentages may help to form a continuum between those of crustaceans and adult cnidarians and ctenophores. As ingestion in the ephyrae was related to their diameter, models suggest that this dilution resulted in an increase in carbon-specific ingestion rate by an estimated 28% relative to an ephyra that did not dilute through development. At the species level, carbon percentage was negatively related to indices of temporal variation in numerical density but not related to rate of population increase. A wide variety of zooplanktonic taxa of different carbon percentages were found to increase in population at a rate that could be considered as forming a bloom. Likewise many gelatinous taxa at L4 did not form blooms. Thus the frequent reference to “jellyfish blooms” reflects, in part, the fact that unlike the other zooplankters that regularly reach even higher carbon concentrations, gelatinous taxa are simply more noticeable to the eye when at these concentrations. Calculating the carbon percentage of whole assemblages could be useful for investigating the influence of environmental parameters on zooplankton. Taken together, these results demonstrate the benefits of explicitly recognising the decoupling of metabolic and ecological body size seen in the gelatinous zooplankton.

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-06-29T17:35:04Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2011-Dissertação-TiagoNunes.pdf: 14422947 bytes, checksum: c5fe4454b1a2c027cf01d48b6015c9ca (MD5) / Made available in DSpace on 2017-06-29T17:35:04Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2011-Dissertação-TiagoNunes.pdf: 14422947 bytes, checksum: c5fe4454b1a2c027cf01d48b6015c9ca (MD5) Previous issue date: 2011-02-28 / Os anfípodos zooplanctônicossão componentes significativos das comunidades epi e mesopelágicas. Ocupam nichos ecológicos diversificados e, em algumas regiões frias, dominam a biomassa planctônica, constituindo os principais itens alimentares depeixes e baleias planctófagos. Como dados sobre composição específica e variabilidade geográfica ainda são escassos especialmente para o oceano Atlântico Sul Ocidental, objetivou-se levantar a composição dos Amphipodapresentes emáguas oceânicas da Zona Econômica Exclusiva (ZEE) do Nordeste do Brasil, contribuindo para o conhecimento taxonômico de distribuição horizontal. Duas hipóteses foram testadas:1) possuem alta diversidade na área, constituindo uma comunidade complexa, porém, pouco abundante; 2) há espécies que ocorrem exclusivamente na região, em relação às demais águas brasileiras. Um total de 43 amostras de macrozooplâncton foi analisado,amostras essas coletadas entre junho e julho de 1998 nas áreas: Oceânica Este (OE), Arquipélago São Pedro e São Paulo (ASPSP) e Cadeia Rocas/Noronha (CRN), parte integrante do Projeto REVIZEE Score NE-III. As amostras foram obtidas no estrato de0 a200m através de arrastos oblíquos, com rede de náilon do tipo bongo, com abertura de malha de 300μme 500μmdurante 15 minutos,acoplada com fluxômetro digital. Para este trabalho foi utilizado o material retido na malha de 300μm. Dados de temperatura e salinidade foram igualmente aferidos. O material biológico foi fixado a bordo, emuma solução de formaldeído a 4% neutralizado com tetraborato de sódio. Os indivíduos foram separados, dissecados e identificados até a menor unidade taxonômica possível. Observou-se uma densidade máxima de 1,92 org.m-3na E111 (ASPSP), e uma mínima de 0,175 org.m-3na E143 (OE). Foram identificadas 68 espécies, sendo 5 da subordem Gammaridea e 63 da Hyperiidea, além de cinco instantes de associação com organismos gelatinosos. Eupronoe intermedia, Hyperietta vosseleri, Anchylomera blossevillei,Phronimella elongata,Lycaeopsis zamboangaee Primno latreilleiforam consideradas muito frequentes, sendo as quatro primeiras aquelas que se sobressaíram em abundância (12,6%; 21,4%; 11,5%; 10,2%, respectivamente), consideradas pouco abundantes, e todas as outras, raras. O ASPSP foi a área que apresentou maior diversidade e equitabilidade (4,248 bits.ind-1e E= 0,761). Segue-se a elea CRN (3,878 bits.ind-1e E= 0,744) e a OE (3,766 bits.ind-1e E= 0,654). Esses valores expressam uma altaequitabilidade e diversidade para a área estudada, quando comparados a valores encontrados na literatura para outras áreas marinhas do Brasil e do mundo; a primeira, expressando uma boa distribuição dos organismos ao longo da coluna d’água, e a segunda, corroborando a hipótese de que os anfípodos zooplanctônicos apresentam, da zona nerítica em direção à oceânica, uma diminuição na densidade e aumento na diversidade. Este estudo contribui ainda com sete novas ocorrências para o Nordeste do Brasil e duas para o Atlântico Sul Ocidental. / Zooplanktonic amphipods are significant components of the epi-and mesopelagic communities. They occupy diverse ecological niches and, in some cold regions, dominate the plankton biomass, constituting the food bank for fish and plankton whales. Given the data on species composition and geographic variability are scarce, especially for the South Atlantic Ocean, the main goal of thisdissertation was to register the composition of crustaceans found in ocean waters of the Exclusive Economic Zone (EEZ) of the Northeast of Brazil, contributing to the knowledge of the taxonomy and biogeography of this group. Two hypothesis were tested: (1) the diversity of zooplanktonic amphipods at this area is high, representing a complex but not abundant community; (2) there are exclusive species at the region level in comparison to other Brazilian marine areas. I analyzed 43 samples of macrozooplankton collected between June and July 1998 in: Oceânica Este (OE), São Pedro and São Paulo archipelagos (SP/SP) and Cadeia Rocas/Noronha (CRN). All samples were obtained in a depth between 0 e 200m by through oblique hauls lasting 15 minutes with a nylon mesh-type bong, with the gap between 300μm mesh coupled with digital flowmeter. Biological material was fixed aboard with formaldehyde 4% neutralized with sodium tetraborate. Individuals were dissected and identified at the lowest taxonomic level it was possible. It was observed the maximum density of 1,92 org.m-3at E111 (SP/SP), and the minimum density of 0,175 org.m-3at E143 (OE). I identified 68species: 5 fromthe sub-order Gammaridea and 63 from the sub-order Hyperiidea; five associations with gelatinous zooplankton were also found. Eupronoe intermedia, Hyperietta vosseleri, Anchylomera blossevillei,Phronimella elongata,Lycaeopsis zamboangaeand Primno latreilleiwere considered frequent species. Among them, the first four species were also considered not abundant (12,6%; 21,4%; 11,5%; 10,2%, respectively).SP/SP was the area with the highest diversity and evenness(4,248 bits.ind-1; E= 0,761), followed by CRN (3,878 bits.ind-1; E= 0,744) and OE (3,766 bits.ind-1; E= 0,654). Thesevalues expressahigh evennessand diversityin the studyareawhen compared tovalues foundin the literature forothers Brazilianand globalmarine areas. Evenness results expressingagooddistribution of organismsthroughout thewater column; and diversity values are supporting the hypothesisthat zooplanktonic amphipodsexhibita decreasein the density andincreasein the diversity, from theneriticzonetoward theoceanic zone. Seven species are new register for the Northeastern region of Brazil and other two species, for Western South Atlantic (also exclusively occurring at Northeastern region).

O filo Ctenophora tem sido negligenciado em estudos faunísticos e ecológicos no Brasil. São escassos os registros de espécies e pouco se sabe sobre a distribuição e abundância destes animais em águas brasileiras. Muito dessa falta de informações sobre o grupo se deve às dificuldades em se coletar e preservar espécimes. O presente estudo consistiu em um esforço no sentido de se conhecer um pouco mais sobre os ctenóforos, nos âmbitos faunístico, taxonômico e ecológico. A tese foi dividida em seis capítulos: o primeiro faz uma introdução ao estudo dos Ctenophora; o segundo traz descrições das sete espécies que ocorrem no Canal de São Sebastião; o terceiro traz uma chave de identificação para as treze espécies registradas para a costa brasileira, incluindo um glossário de termos específicos; o quarto aborda o problema taxonômico relativo ao ctenóforo Mnemiopsis leidyi, apresentando uma solução para tal; o quinto contempla a biologia populacional de M. leidyi na costa brasileira, a questão do impacto predatório da espécie em diversas regiões do mundo e sua recente introdução nos mares do Norte e Báltico; o último apresenta considerações gerais sobre os resultados dos capítulos anteriores. Desta forma, procurei abordar diversos aspectos da taxonomia e biologia dos ctenóforos presentes na costa brasileira e espero, assim, ter conseguido efetuar algum avanço no conhecimento deste grupo, ainda muito carente de estudos no Brasil e no mundo. / The phylum Ctenophora is pour studied in Brazil. Species records for the Brazilian coast are scarce in the literature. The distribution patterns and abundance of ctenophores in the region are almost unknown. The scarcity of data aims mostly to the difficulties in collecting and preserving specimens. This study consisted in an effort to increase knowledge on the faunistics, taxonomy and ecology of the ctenophores from Brazilian waters. Dissertation was divided in six chapters. The first on introduces the Ctenophora study. The second presents description of the seven species found in the São Sebastião Channel. The third chapter is an identification key to the species reported for the Brazilian coast, with a glossary on specific terms. The fourth regards the taxonomical problem of Mnemiopsis leidyi and suggests a solution for it. The fifth presents the population biology of M. leidyi from the Brazilian coast, the predatory impact of the species in several areas of the world and its recent introduction in the North and Baltic seas. The last chapter summarizes the final conclusions of the previous chapters. Thus, in hope of fulfilling a gap on these animals knowledge, I tried to contemplate several aspects of taxonomy and biology of the ctenophore species from the Brazilian coast.

This research focused on population dynamics of two gelatinous zooplankters (Aequorea & Pyrosoma atlanticum) in the northern California Current to assess their relationship to environmental conditions and role in the pelagic ecosystem. Data collected since 1999 showed seasonal and interannual fluctuations in the abundance and distribution of Aequorea in the NCC, with a positive correlation with sea surface temperature and salinity. Pyrosoma atlanticum, which are typically found in tropical waters, have only been observed in high abundances in the NCC since 2014 and their role in the pelagic ecosystem is not well understood. Pyrosome abundance related to in situ environmental variables showed a positive correlation with warmer SST. We also used fatty acids as trophic markers to better understand pyrosome trophic ecology in the NCC. FA biomarkers suggest that pyrosomes have a broad phytoplankton diet, which may indicate an ability to inhabit warmer, lower nutrient zones. / 2020-01-11

The distribution, abundance, chemical composition, metabolism, and feeding ecology of the tentaculate ctenophore, Callianira antarctica (Chun 1897), were investigated during austral winter 2001and autumn & winter 2002, in the vicinity of Marguerite Bay west of the Antarctic Peninsula. Callianira antarctica had a widespread distribution during autumn and winter, and variable abundance (0.02 to 2.6 ind. m-2) during winter 2001 associated with specific circulation features. Size frequency distributions for autumn and winter suggest that more than half of the C. antarctica population may have experienced 'degrowth' during winter due to low food availability. Callianira antarctica is a fairly robust ctenophore with geometric mean (geomean) carbon (C) and nitrogen (N) values of 8.41 and 1.83% dry weight (DW), respectively. Winter oxygen consumption and ammonium excretion rates ranged from 0.059 to 0.410 micro l O2 [mg DW]-1 h-1 and 0.60 to 31.1 µg-at N [g DW]-1 h-1, respectively, at 0oC. Daily minimum maintenance rations based on respiration experiments were 2.7% to 3.6% of the total body carbon (TBC) for small ctenophores, and 1.4% to 1.9% TBC for larger ctenophores. Calanoid copepods and larval and juvenile Antarctic krill were offered to ctenophores in incubation experiments. Digestion times were variable, lasting 8 to 20 h, and were independent of ctenophore size and dependent on number and type of prey. Gut content analysis from one autumn and two winter seasons indicated C. antarctica preyed on both copepods and krill in situ, with an increased dependence on larval krill during winter. Lipid biomarker analysis on C. antarctica and their potential prey confirmed these results. Divers observed aggregations of C. antarctica passively drifting with tentacles extended near dense concentrations of larval Euphausia superba during winter. These observations along with gut content and lipid biomarker analysis suggest that larval krill is an important prey item for C. antarctica during winter.

Made available in DSpace on 2016-06-02T19:28:53Z (GMT). No. of bitstreams: 1 TeseMJDO.pdf: 1550379 bytes, checksum: 5ca8c2ddbfc8ee491b380e078a951b9f (MD5) Previous issue date: 2006-03-13 / Universidade Federal de Minas Gerais / (Gelatinous aggregates (lake snow) from an eutrophic Brazilian reservoir and their relationships with abundant phytoplanktonic algae). Lake snow and phytoplankton studies were conduced in Barra Bonita Reservoir, in the Tietê River basin, southeastern Brazil. Monthly sampling from April 2002 to January 2004 and two intensive sampling (dry and wet periods) were performed in six depths (0m, 1m, 3m, 5m, 10m and 17m deep), at a sample station localized 3km upstream the reservoir dam. Among the sampled months the highest numbers of aggregates were registered in August 2002 (167 agg.L-1) and September 2002 (230 agg.L-1). The mean numbers of aggregates registered in the intensive samplings was 38 agg.L-1 in June 2003 and 68 agg.L-1 in December 2003. Seasonal occurrence of algal species aggregated to polysaccharidic matrices followed the dynamic of dominant species in the Reservoir. Aulacoseira granulata and free cells of Microcystis sp. were the most frequent taxa in the aggregates (70%) in the majority of samples. Other species, as Pseudanabaena mucicola, Microcystis aeruginosa, Planktothrix tropicalis, Cyclotella menegheniana, Cryptomonas sp, Actinastrum hantzschii, Quadrigula lacustris and Schroederia indica were registered in less frequency (10% to 15%). The monosaccharide composition of the gelatinous aggregated polysaccharides was the same registered in dissolved carbohydrates samples, reinforcing the importance of phytoplankton as the major source, chiefly of polysaccharides and of the gelatinous aggregates in the transport of these sugars through the water column. However, studies concerning gelatinous aggregates in freshwater are recent and more investigation are needed to confirm the patterns showed in our results. / (Estudo dos agregados gelatinosos (lake snow) no reservatório de Barra Bonita e sua relação com as algas fitoplanctônicas abundantes). O estudo dos agregados foi realizado em coletas mensais (abril de 2002 a janeiro de 2004) e intensivas (períodos seco e chuvoso), em seis profundidades na coluna d água (0m, 1m, 3m, 5m, 10m e 17m), em um ponto fixo do reservatório, localizado 3 km a montante da barragem. Nas coletas mensais, o maior número de agregados foi registrado nos meses de agosto/02 (167 agg.L-1) e setembro/02 (230 agg.L-1). Durante as coletas intensivas o número de agregados foi, em média, de 38 agg.L-1 em junho e de 68 agg.L-1 em dezembro. A ocorrência sazonal das espécies algais agregadas às matrizes polissacarídicas, acompanhou a dinâmica das espécies abundantes no reservatório. Aulacoseira granulata e células livres de Microcystis sp, foram os táxons mais freqüentes nos agregados (70%) na maioria das coletas. Outras espécies, como Pseudanabena mucicola, Microcystis aeruginosa, Planktothrix tropicalis, Cyclotella menegheniana, Cryptomonas sp, Actinastrum hantzschii, Quadrigula lacustris e Schroederia indica, foram registradas com menor freqüência (10% a 15%). A composição monossacarídica dos polissacarídeos dos agregados gelatinosos foi a mesma registrada nas amostras de carboidratos dissolvidos, reforçando a importância do fitoplâncton como principal fonte, principalmente de polissacarídeos e dos agregados gelatinosos no transporte destes açúcares através da coluna d água. Porém, os estudos envolvendo os agregados gelatinosos em água doce, são recentes e necessitam de maiores investigações.

O filo Ctenophora tem sido negligenciado em estudos faunísticos e ecológicos no Brasil. São escassos os registros de espécies e pouco se sabe sobre a distribuição e abundância destes animais em águas brasileiras. Muito dessa falta de informações sobre o grupo se deve às dificuldades em se coletar e preservar espécimes. O presente estudo consistiu em um esforço no sentido de se conhecer um pouco mais sobre os ctenóforos, nos âmbitos faunístico, taxonômico e ecológico. A tese foi dividida em seis capítulos: o primeiro faz uma introdução ao estudo dos Ctenophora; o segundo traz descrições das sete espécies que ocorrem no Canal de São Sebastião; o terceiro traz uma chave de identificação para as treze espécies registradas para a costa brasileira, incluindo um glossário de termos específicos; o quarto aborda o problema taxonômico relativo ao ctenóforo Mnemiopsis leidyi, apresentando uma solução para tal; o quinto contempla a biologia populacional de M. leidyi na costa brasileira, a questão do impacto predatório da espécie em diversas regiões do mundo e sua recente introdução nos mares do Norte e Báltico; o último apresenta considerações gerais sobre os resultados dos capítulos anteriores. Desta forma, procurei abordar diversos aspectos da taxonomia e biologia dos ctenóforos presentes na costa brasileira e espero, assim, ter conseguido efetuar algum avanço no conhecimento deste grupo, ainda muito carente de estudos no Brasil e no mundo. / The phylum Ctenophora is pour studied in Brazil. Species records for the Brazilian coast are scarce in the literature. The distribution patterns and abundance of ctenophores in the region are almost unknown. The scarcity of data aims mostly to the difficulties in collecting and preserving specimens. This study consisted in an effort to increase knowledge on the faunistics, taxonomy and ecology of the ctenophores from Brazilian waters. Dissertation was divided in six chapters. The first on introduces the Ctenophora study. The second presents description of the seven species found in the São Sebastião Channel. The third chapter is an identification key to the species reported for the Brazilian coast, with a glossary on specific terms. The fourth regards the taxonomical problem of Mnemiopsis leidyi and suggests a solution for it. The fifth presents the population biology of M. leidyi from the Brazilian coast, the predatory impact of the species in several areas of the world and its recent introduction in the North and Baltic seas. The last chapter summarizes the final conclusions of the previous chapters. Thus, in hope of fulfilling a gap on these animals knowledge, I tried to contemplate several aspects of taxonomy and biology of the ctenophore species from the Brazilian coast.

Members of the family Platytroctidae (tubeshoulders) are found throughout the meso- and bathypelagic waters of the World Ocean. Due to the lack of specimens collected globally, this taxon has received little attention, despite recent evidence suggesting its predominance in the bathypelagic biome. Prior to this study, only four species had been reported in the Gulf of Mexico’s (GoM) highly diverse deep-pelagic ecosystem. An extensive meso- and bathypelagic trawl series in the GoM allowed a detailed examination of this family, which included analyses of species composition, abundance, vertical distribution, sex ratios, and trophic ecology. A total of 16 species were collected, which included 12 new records for the GoM. The five most-abundant species collected were Mentodus facilis, Platytroctes apus, Barbantus curvifrons, Mentodus mesalirus, and Maulisia microlepis. All platytroctids were collected from tows that extended below 700 m. Mentodus facilis was the only species that significantly differed from the expected 1:1 sex ratio (pMentodus mesalirus and Maulisia microlepis heavily consumed gelatinous zooplankton. Mentodus facilis and Barbantus curvifrons had a more varied diet consuming chaetognaths, copepods, and ostracods, with M. facilis exhibiting a slightly greater reliance on ostracods and gelatinous prey. This study represents the first investigation into the diet of this fish family and adds to the sparse community data of the bathypelagic zone by identifying alternative nutrient pathways (e.g., the fish-jelly link) that connect the deep and upper oceanic ecosystems.

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Phytoplankter sind die bedeutendsten Primärproduzenten in aquatischen Ökosystemen und leisten ca. 45 % der globalen Primärproduktion. Sie weisen eine hohe taxonomische Diversität mit vielfältigen morphologischen und physiologischen Eigenschaften auf. Funktionelle Eigenschaften, die das licht-, temperatur- und nährstoffabhängige Wachstum sowie Verlustgrößen (Fraß, Sedimentation) beschreiben, sind eine Möglichkeit Phytoplankter zu klassifizieren. Diese Einteilung gewinnt für das Verständnis und die Modellierung der Phytoplanktonsukzession (z.B. in Wassergütemodellen) immer mehr an Bedeutung, da nicht taxonomische, sondern funktionelle Eigenschaften das Vorkommen der Phytoplankter im Gewässer bestimmen. Das Wassergütemodell SALMO ist ein mechanistisches, dynamisches, vertikales 1D-Modell, welches Nährstoffe, Sauerstoff, Detritus, 4 funktionelle Phytoplanktontypen und eine Zooplanktonmischgruppe simuliert. Bei der Modellanwendung wurde ersichtlich, dass die vorhandenen funktionellen Typgruppen teilweise nicht ausreichen, um die funktionelle Diversität der realen Phytoplanktongemeinschaften adäquat widerzuspiegeln. Deshalb wird eine Erweiterung der funktionellen Typgruppen in SALMO angestrebt. Eine empirische Freilanddatenanalyse an zwei morphologisch und trophisch verschiedenen Talsperren ergab insgesamt 10 funktionelle Phytoplanktontypen (Typgruppen 1, 2 und 4 bereits in SALMO vorhanden). Die bestehenden funktionellen Eigenschaften wurden erweitert und teilweise verändert (insgesamt 10 funktionelle Eigenschaften). Die neue funktionelle Typgruppe 6 (unbewegliche, koloniale, gelatinöse Chlorophyceen) wurde in lichtabhängigen Wachstumsversuchen und Fraßversuchen mit Daphnia galeata × hyalina genauer untersucht. Als stellvertretende Art für diese Typgruppe wurde Sphaerocystis schroeteri gewählt. Die Wachstumsversuche bei 20 °C kennzeichneten Sphaerocystis als Starklichtart mit einer relativ hohen Wachstumsrate (Iopt = 250 µmol m-2 s-1; µmax = 0.96 d-1; 12:12 h Hell-Dunkelzyklus). Eigene Nährmediumsversuche wiesen auf eine Abhängigkeit von freiem CO2 hin. Dies bietet eine Erklärung für ihr häufiges Auftreten in oligo- bis mesotrophen Gewässern. Bei Anwesenheit von Daphnia konnte nach 96 h Versuchsdauer eine signifikante Erhöhung der Koloniegröße (Anteil nicht fressbarer Kolonien 3-74 %), im Vergleich zur Kontrolle (Anteil nicht fressbarer Kolonien 0-5 %), festgestellt werden. Dies stellt einen effektiven Fraßschutz gegen größenselektiv filtrierendes Zooplankton wie z.B. Daphnia dar und kann bei hohem Fraßdruck zur Dominanz der Typgruppe führen (z.B. Klarwasserphase in eutrophen Gewässern). Der Effekt war nicht durch Infochemikalien induzierbar. Aus Literaturdaten wurde eine relativ hohes Topt von 27 °C, eine nur mäßige Konkurrentstärke um Phosphor (mittlerer KP-Wert) sowie eine Brutto-Sinkgeschwindigkeit von 1.5 m d-1 entnommen werden. / Phytoplankter are the most important primary producer in aquatic ecosystems and contribute about 45 % to global primary production. Phytoplankton communities usually show an enormous taxonomical diversity. However, besides taxonomical diversity, a phytoplankton can also be characterised by its functional diversity by means of functional traits like resource-dependent growth characteristics (e.g. KI-, KP-, KN-values) or sensitivity to zooplankton grazing and sedimentation. Since functional, and not taxonomic, traits drive the phytoplankton succession, a functional classification of phytoplankton is recognised to be increasingly important for the ecological understanding and modelling of plankton succession (e.g. in water quality models). The mechanistic, dynamic, vertical 1D water quality model SALMO simulates the dynamics of nutrient concentrations (P, N), oxygen, detritus, 4 functional phytoplankton types and 1 mixed zooplankton group. Different model applications showed that the number of phytoplankton types in SALMO was sometimes not sufficient for accounting for the observed functional diversity in phytoplankton communities. Therefore, the aim of this thesis is to extend the functional diversity of phytoplankton types in SALMO. After careful evaluation of empirical data from two reservoirs with different morphology and trophic state 10 functional phytoplankton types are proposed (types 1, 2 and 4 remained unchanged). Existing functional traits in SALMO were extended and partly changed (in total 10 functional traits). For the new functional phytoplankton type 6 (non motile, colonial gelatinous green algae) light-dependent growth rates were measured and grazing experiments with Daphnia galeata × hyalina were carried out in the laboratory. For these experiments, Sphaerocystis schroeteri was chosen as representative species for this group. It is characterised by high light demand and relative high growth rates at 20 °C (µmax = 0.96 d-1, Iopt = 250 µmol m-2 s-1, 12:12 h light-dark cycle). Their growth depends on the availability of free CO2. This explains the common occurrence in oligo-mesotrophic water bodies. The range of the colony sizes of Sphaerocystis increased in the presence of Daphnia significantly (portion of inedible colonies 3-74 %) in contrast to the control (portion of inedible colonies 0-5 %). This was induced by direct size-selective grazing and not by infochemicals. Thus, Sphaerocystis has evolved an effective defence mechanism against size-selective filter-feeding zooplankton and is competitive superior at high zooplankton grazing pressure (e.g. clear water stage in eutrophic waters). The lack of experimentally derived parameters for temperature- and phosphorus-depending growth (Tmin, Topt, KP-value) as well as gross sinking velocity was complemented with literature data. The alga is only moderately competitive for phosphorus and exhibits relatively high minimal and optimal growth temperatures (Tmin = 7 °C, Topt = 27 °C). Since type 6 consists of large, non motile species, gross sinking velocity was estimated to be about 1.5 m d-1.