Search results for "phytoplankton"

Lake zooplankton delta13C values are strongly correlated with the delta13C values of distinct phytoplankton taxa

2016

Article

Directional high-throughput sequencing of RNAs without gene-specific primers.

2018

Ribosomal RNA analysis is a useful tool for characterization of microbial communities. However, the lack of broad-range primers has hampered the simultaneous analysis of eukaryotic and prokaryotic members by amplicon sequencing. We present a complete workflow for directional, primer-independent sequencing of size-selected small subunit ribosomal RNA fragments. The library preparation protocol includes gel extraction of the target RNA, ligation of an RNA oligo to the 5′-end of the target, and cDNA synthesis with a tailed random-hexamer primer and further barcoding. The sequencing results of a phytoplankton mock community showed a highly similar profile to the biomass indicators. This method…

Biological and Ecological Features, Trophic Structure and Energy Flow in Meromictic Lakes

2017

Case studies and typical examples for meromictic lakes are used to provide a review of the biology and ecology of these ecosystems. Water column in meromictic lakes is not entirely mixed. These lakes are chemically and/or thermally stratified for several years and have several specific ecological features. The chemocline —the habitat created between the mixolimnion on top and monimolimnion below—is characterised by the existence of complex bacterial communities, autotrophic and heterotrophic protists and metazooplankton, commonly dominated by rotifers , high rates of oxygenic and anoxygenic photosynthesis and some biogeochemical processes . In these lakes, the sulphur, carbon and nitrogen c…

Sample Preservation, DNA or RNA Extraction and Data Analysis for High-Throughput Phytoplankton Community Sequencing

2017

Phytoplankton is the basis for aquatic food webs and mirrors the water quality. Conventionally, phytoplankton analysis has been done using time consuming and partly subjective microscopic observations, but next generation sequencing (NGS) technologies provide promising potential for rapid automated examination of environmental samples. Because many phytoplankton species have tough cell walls, methods for cell lysis and DNA or RNA isolation need to be efficient to allow unbiased nucleic acid retrieval. Here, we analyzed how two phytoplankton preservation methods, three commercial DNA extraction kits and their improvements, three RNA extraction methods, and two data analysis procedures affect…

2019

Abstract Eutrophication (as an increase in total phosphorus [TP]) increases harmful algal blooms and reduces the proportion of high-quality phytoplankton in seston and the content of ω-3 long-chain polyunsaturated fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) in fish. However, it is not well-known how eutrophication affects the overall nutritional value of phytoplankton. Therefore, we studied the impact of eutrophication on the production (as concentration; μg L−1) and content (μg mg C−1) of amino acids, EPA, DHA, and sterols, i.e., the nutritional value of phytoplankton in 107 boreal lakes. The lakes were categorized in seven TP concentration categories ranging f…

Fitoplancton de dos lagunas de los humedalesde Xeresa y Xeraco (Valencia, España).

2001

M.Jose.Villena@uv.es Susana.Romo@uv.es Se ha estudiado la composición fitoplanctónica de dos lagunas costeras mediterráneas, que corresponden a los marjales de Xeresa y Xeraco (Valencia). Estas zonas húmedas de la Comunidad Valenciana poseen un importante valor ecológico y botánico para nuestra Península, aunque actualmente se encuentran amenazadas por transformaciones de tipo turístico o agrícola. Las lagunas estudiadas se caracterizan por ser someras (Zmax: 3 m), oligohalinas, de aguas transparentes y mesotróficas, y por encontrarse sobre lechos de turba y con praderas de macrófitos sumergidos. El fitoplancton observado destaca por presentar una composición similar para ambas lagunas, con…

Factors controlling planktonic size spectral responses to autumnal circulation in a Mediterranean lake

2006

14 pages, and figures, and tables statistics.

Autotrophic and Heterotrophic Picoplankton in Wetlands: Differences with Lake Patterns

2003

This study describes the occurrence, importance and seasonal patterns of picoplankton in two wetlands (TDNP and La Safor), and compares them to a system of fifteen interconnected lakes (Ruidera). In TDNP we performed a six-year monthly study in three sites of the wetland. Bacterial abundance increased throughout time and the autotrophic picoplankton (APP) range was wide (up to 33 x 10 6 cells/ml). The annual averaged APP contribution to total picoplankton and phytoplankton biovolumes was 0.5-22% and 0.03-6% respectively. There were large differences among sites in terms of APP absolute and relative abundance and seasonal patterns. In La Safor, the APP relative contribution to picoplankton a…

Seasonal succession and growth in the plankton communities of the Gulf of Riga in relation to long-term nutrient dynamics

1999

To study temporal changes in phyto- and zooplankton in the Gulf of Riga monitoring data covering the period of 1972–1995 were analyzed. Changes in external nutrient supply have turned P limitation, during the 1980s, into the present deficiency of Si for the spring bloom. Contrary to depletion of the N and Si pools, the internal sources and sinks were responsible for input of P into the pelagic ecosystem in the 1990s. Restructuring of the nutrient pool reshaped the pelagic planktonic communities. Changes of the species composition and food-web relationships occurred. Till the 1990s, an increase of diatoms in the summer phytoplankton and an increase of herbivores in zooplankton took place. La…

Phytoplankton structure in different lake types in central Finland

1986

Phyloplankton structure and its relation to physical and chemical properties of the water was studied in 58 central Finnish lakes. The biomass ranged from 0.2 to 14.2 g m−3 and the number of taxa per sample ranged from 33 to 152. The lakes were grouped into 5 types according to their trophic state: eutrophic, dyseutrophic, mesotrophic, oligotrophic, and acid oligotrophic lakes. The average biomass in eutrophic lakes was 5.57 g m−3, in dyseutrophic 3.54 g m−3, 1.23 g m−3 in mesotrophic, 0.52 g m−3 in oligotrophic and 0.39 g −3 in acid oligotrophic lakes. The average number of taxa per sample in the corresponding lake types were 109. 1, 79.3, 97.9, 90.9 and 43.8, respectively. The phytoplankt…