| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Strogyloudi, Evangeli, et al.
(författare)
-
Estimating the accumulation and transfer of Nodularia spumigena toxins by the blue mussel Mytilus edulis: An appraisal from culture and mesocosm experiments
- 2006
-
Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 48:4, s. 359-372
-
Tidskriftsartikel (refereegranskat)abstract
- 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 mu g nodularin 1(-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 mu g of nodularin g dw(-1) of the mussel whole body tissue after 12h. 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, relative to the amount contained in the offered food, varied from 10% to 20%, depending on food quality. During a 5-day toxin accumulation experiment, the acute reduction of the toxin in mussel tissues the second day and the following stabilization, showed that probably mussels maintain low toxin levels via efficient elimination and/or toxin metabolism. After a 72 h depuration period, mussels showed 75% reduction in their toxin content.
|
|
| 7. |
|
|
| 8. |
- Alder, V A, et al.
(författare)
-
Macro- and micrograzing effects on phytoplankton communities
- 1989
-
Ingår i: The expedition Antarktis VII/3 (EPOS LEG 2) of RV "Polarstern" in 1988/89. - Bremerhaven : Alfred- Wegener-Institut für Polar Meeresforschung. ; , s. 123-130
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
- Barreiro, A, et al.
(författare)
-
Relative importance of the different negative effects of the toxic haptophyte Prymnesium parvum on Rhodomonas salina and Brachionus plicatilis
- 2005
-
Ingår i: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 38:3, s. 259-267
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the relative importance of the different processes/mechanisms by which the toxic haptophyte Prymnesium parvum, cultured under different nutrient conditions, affects non-toxic phytoplankton competitors and microzooplankton grazers. P. parvum was cultured under steady-state growth in different nutrient conditions: nitrogen depleted (-N), phosphorus depleted (-P) and balanced nitrogen and phosphorus (+NP). Cells from each nutrient condition and culture cell-free filtrates, alone and combined with non-toxic prey (Rhodomonas salina), were used as food for the rotifer Brachionus plicatilis. An additional experiment was carried out to test the effect of P. parvum cells and culture cell-free filtrate on R. salina. The highest haemolytic activity values were achieved by -P F parvum cultures, followed by -N. However, the negative effect of R parvum on R. salina and rotifers did not correlate with haemolytic activity but with the number of P. parvum cells. -N-cultured P. parvum were the most toxic for both R. salina and rotifers, followed by +NP. Therefore, haemolytic activity is not a good indicator of the total potential toxicity of R parvum. The growth rate of R. salina was negatively affected by cell-free filtrates but the effect of P, parvum predation was greater. Rotifers fed on both toxic and non-toxic algae, indicating that they did not select against the toxic alga. The P. parvum cell-free filtrate had an effect on B. plicatilis, although this was weak, B, plicatilis was also indirectly affected by P. parvum due to the negative effects of the toxic alga on their prey (R. salina). However, the greatest negative effect of P. parvum on the rotifers was due to ingestion of the toxic cells. Therefore, the phytoplankton competitor R. salina is more affected by P. parvum predation and the grazer B. plicatilis is more affected by ingestion of the toxic cells, the effects of excreted compounds being secondary.
|
|
| 10. |
- Bertilsson, S, et al.
(författare)
-
Size-selective predation on pelagic microorganisms in Arctic freshwaters
- 2003
-
Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 25:6, s. 621-631
-
Tidskriftsartikel (refereegranskat)abstract
- Herbivorous zooplankton may have a pronounced influence on pelagic microorganisms in Arctic freshwaters. We quantified experimentally the size-selective feeding of several zooplankton groups on pelagic microorganisms in high Arctic tundra systems. Our experiments and field study focused on dominant herbivores in Arctic freshwaters, including the cladoceran Dophnia, the copepod Diaptomus and the anostracan Branchinecta, and their effects on prey ranging in size from bacteria to large phytoplankton. Grazing experiments showed that Dophnia were effective predators on all types of prey, whereas Diaptomus grazed preferentially on larger phytoplankton with low clearance rates for bacterial cells. Further analysis by flow cytometry indicated that Diaptomus grazed selectively on the largest bacteria. In contrast to the results obtained in the controlled experiments, Arctic lakes and ponds with a zooplankton community dominated by Dophnia had a higher bacterial production and abundance than systems not dominated by this grazer. This may indicate that the stimulatory effect of grazers on bacterial growth is more pronounced in natural systems, or that factors other than zooplankton grazing are more important in regulating bacterial abundance and production in natural systems. Although Arctic waters differ considerably from temperate systems with respect to temperature and light regime, herbivore-prey dynamics as well as the bacterial response to temperature appear to be similar between the climatic regions.
|
|
