Search results for "plank"

A multivariate analysis of phytoplankton and food web changes in a shallow biomanipulated lake

1996

1. Phytoplankton dynamics, food chain changes and resilience in Lake Zwemlust, a shallow lake in The Netherlands, are described for the period 1986-94. 2. After biomanipulation in 1987, the lake moved through two alternative states, while the external nutrient loadings were maintained. A clear-water phase, mostly dominated by macrophytes, persisted from 1987 to 1991, and a rather turbid state, dominated by algae, occurred in the summers of 1992-94, after several consecutive and sustained perturbations affecting different parts of the food web in the lake. These two periods were characterized by different community structures. 3. The phytoplankton assemblage gradually changed in a pattern th…

Ten Years of Paleoceanographic Studies at ODP Site 963 (Central Mediterranean Sea)

2014

The geographical location, the shape and the circulation pattern makes the Mediterranean Sea an ideal laboratory to study the interplay between different climatic systems, abrupt climate changes and the response of marine ecosystems. The Ocean Drilling Program Site 963 was drilled in the Northwestern part of the Sicily Channel, the sill that divides the western from the eastern Mediterranean Sea. Numerous papers have been published on Site 963 sediments in the last decade, investigating Mediterranean paleoceanographic themes. Here we offer a synthetic framework of these investigations carried out by sub-centennial resolution. We present the whole sequence of suborbital climatic oscillations…

Sea Surface Temperatures and Paleoenvironmental Variability in the Central Mediterranean During Historical Times Reconstructed Using Planktonic Foram…

2019

The ongoing anthropogenic‐induced warming assessment requires a robust background from regional sea surface temperature (SST) reconstructions. Planktonic foraminifera have yielded valuable insights into late Quaternary SST dynamics, but the techniques to estimate SST from fossil assemblages have only rarely been used in very recent sedimentary records (the last 2,000 years). Here we use two transfer function methods, modern analog technique and artificial neural networks, to reconstruct SST variability in two cores from the Central Mediterranean Sea that span the last five centuries. Both cores show similar and considerable changes in the planktonic foraminifera assemblages. However, the in…

UV Radiation and Freshwater Zooplankton: Damage, Protection and Recovery

2011

While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiological protection mechanism seems to be superior, and while several unexplained and contradictory patterns exist in zooplankton UVR ecology, recent increases in our understanding are consistent with UVR pl…

Metālisko elementu bioakumulācija Baltijas jūras un Rīgas līča gliemenēs un planktonā

2016

Metālisko elementu bioakumulācija Baltijas jūras un Rīgas līča gliemenēs un planktonā. Pārpuce S. Darba vadītāji: prof., Dr. ķīm. Vīksna A.; pētniece, Dr. ķīm. Poikāne R. Maģistra darbs, 64 lappuses, 40 attēli, 9 tabulas, 46 literatūras avoti, 5 pielikumi. Latviešu valodā. Darbā apkopota informācija par metālisko elementu un to savienojumu transformācijām, iedarbību un pārvietošanas ceļiem dzīvajos organismos. Kā arī ir pētīta metālisko elementu bioakumulācija un biokoncentrēšana planktonā un gliemenēs. Ir izpētīta literatūrā pieejamā informācija par iespējamajiem kļūdaino elementu uzņemšanas mehānismiem planktonos un gliemenēs. Eksperimentālajā daļā planktona un gliemeņu paraugi tika ievāk…

Reply to LoganDodge: 'stable isotopes challenge the perception of ocean sunfish Mola mola as obligate jellyfish predators'.

2013

Syvaranta et al. (2012) recently provided stable-isotope data from eight small-bodied ocean sunfish Mola mola (L. 1758) captured from the Italian fishing port of Camogli on the Ligurian coast. Representative data were also given for members of pelagic and neritic–coastal food webs. The level of 13C and 15N enrichment shown by M. mola relative to their putative obligate diet of gelatinous zooplankton (gelata) (based on the locally dominant Pelagia noctiluca and literature data) was used to question their obligate consumption of such prey. Furthermore, the M. mola were isotopically more similar to neritic rather than pelagic fishes captured locally, prompting the suggestion that juvenile M. m…

Stable isotopes challenge the perception of ocean sunfish Mola mola as obligate jellyfish predators

2011

Evidence is provided from stable isotope analysis that aggregations of small ocean sunfish Mola mola (total length <1 m) feed broadly within coastal food webs and their classification as obligate predators of gelatinous zooplankton requires revision.

Summaries of presentations during the sixth Workshop of the International Association of Phytoplankton Ecology and Taxonomy, Mondsee, Austria, 15–25 …

1987

Use and misuse in the application of the phytoplankton functional classification: a critical review with updates

2008

Since its publication, the article ‘Towards a functional classification of the freshwater phytoplankton’ (Reynolds et al., J Plankton Res 24: 417–428, 2002), has attracted the attention of dozens of phytoplankton ecologists worldwide. These numerous applications of the functional classification to describe phytoplankton patterns in various aquatic ecosystems allowed the recognition of some uncertain features of this concept originating from various reasons. In this article, we attempt to facilitate the application of the functional classification, by providing a detailed description of the typical misplacements and by modifying some of the original habitat templates and species allocations.…

Are there steady-state phytoplankton assemblages in the field?

2003

The difficulty in advancing in Ecology is due, in part, to the fact that this science uses a mainly qualitative language instead of a more formal or mathematical one. Therefore, many ecologists' efforts are expended in controversies resulting from the vagueness of ecological concepts, for example: stability, equilibrium, ecosystem, community, and so on. When approaching the study of steady-state phytoplankton assemblage, the different interpretations of these concepts can paralyse fruitful discussion. In the following pages, there is an endeavour to both restrict and precise the meaning of some of the concepts related to this topic and to broaden the range of possibilities of steady-state i…