| 1. |
- Dinasquet, Julie, et al.
(författare)
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Cascading effects of the ctenophore Mnemiopsis leidyi on the planktonic food web in a nutrient-limited estuarine system
- 2012
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Ingår i: Marine Ecology Progress Serie. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 460, s. 49-61
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Tidskriftsartikel (refereegranskat)abstract
- Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.
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| 2. |
- Fauville, Geraldine, et al.
(författare)
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Using collective intelligence to identify barriers to teaching 12–19 year olds about the ocean in Europe
- 2018
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X. ; 91, s. 85-96
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Tidskriftsartikel (refereegranskat)abstract
- Since the degradation of the marine environment is strongly linked to human activities, having citizens who appreciate the ocean's influence on them and their influence on the ocean is important. Research has shown that citizens have a limited understanding of the ocean and it is this lack of ocean literacy that needs to change. This study maps the European landscape of barriers to teaching 12–19 year olds about the ocean, through the application of Collective Intelligence, a facilitation and problem solving methodology. The paper presents a meta-analysis of the 657 barriers to teaching about the ocean, highlighting how these barriers are interconnected and influence one another in a European Influence Map. The influence map shows 8 themes: Awareness and Perceived knowledge; Policies and Strategies; Engagement, formal education sector; the Ocean itself; Collaboration; Connections between humans and the ocean and the Blue Economy, having the greatest influence and impact on marine education. “Awareness and Perceived knowledge” in Stage 1, exerts the highest level of overall influence in teaching 12–19 year olds about the ocean. This map and study serves as a roadmap for policy makers to implement mobilisation actions that could mitigate the barriers to teaching about the ocean. Examples of such actions include free marine education learning resources such as e-books, virtual laboratories or hands-on experiments. Thus, supporting educators in taking on the challenge of helping our youth realise that the ocean supports life on Earth is essential for education, the marine and human well-being. •Collective Intelligence shows barriers to teaching 12–19 year-olds about the ocean.•Education stakeholder consultations ran in eight European countries.•European influence map represents the relationships among barriers.•Barriers in “Awareness and perceived knowledge” theme are the most influential.•Resources, courses and networks are options that can be used to address barriers.
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| 3. |
- Gambill, M., et al.
(författare)
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Effects of temperature on the feeding and growth of the larvae of the invasive ctenophore Mnemiopsis leidyi
- 2015
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 37:5, s. 1001-1005
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-specific prey clearance and ingestion rates of 1.5-mm tentaculate larvae of the ctenophore Mnemiopsis leidyi increased linearly between 6 and 25 degrees C but declined between 25 and 30 degrees C. Both absolute (length) and carbon-specific growth rate increased linearly with increasing temperature. The latter was 0.87 d(-1) at 25 degrees C. Extremely low or negative growth rates observed at 6 and 30 degrees C help define the thermal limits to population growth of this successful biological invader.
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| 4. |
- Granhag, Lena, 1974, et al.
(författare)
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First recordings of the ctenophore Euplokamis sp. (Ctenophora, Cydippida) in Swedish coastal waters and molecular identification of this genus
- 2012
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1818-5487 .- 1798-6540. ; 7:4, s. 455-463
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Tidskriftsartikel (refereegranskat)abstract
- The ctenophore Euplokamis sp. was observed and collected in the Gullmar fjord on the west coast of Sweden in April-August 2011 during regular jellyfish and zooplankton monitoring. In April-May 2011, both larval and adult Euplokamis sp. were collected in the surface water of the fjord and in June-August in the deep part of the fjord at 110-100 m. The typical morphological and behavioral characters of Euplokamis sp. were observed (i.e. coiled tentacle side branches and rapid swimming both in forward and reverse). With no published sequence data from the ctenophore family Euplokamidae, molecular identification using the nuclear 18S rRNA gene and internal transcribed spacer region I region (ITS1) revealed that Euplokamis sp. individuals were closely related to the morphologically similar ctenophore family Mertensiidae. Therefore, morphological and molecular data support the identification as Euplokamis. Euplokamis sp. densities in the deep water of the Gullmar fjord in June 2011 reached similar densities as the local ctenophore Beroe spp. The presence of Euplokamis sp. and other ctenophores in the area is discussed together with the importance of continuous monitoring of gelatinous forms to include detection of less frequent and more fragile ctenophore species. We also discuss the importance of molecular identification for ctenophore larvae and adult ctenophores of small size.
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| 5. |
- Granhag, Lena, 1974, et al.
(författare)
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Size-specific clearance rates of the ctenophore Mnemiopsis leidyi based on in situ gut content analyses
- 2011
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 33:7, s. 1043-1052
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Tidskriftsartikel (refereegranskat)abstract
- The ctenophore Mnemiopsis leidyi can consume large amounts of zooplankton prey.However, quantitative measurements of feeding rates, based on field data, arescarce. We measured the time required by the invasive M. leidyi to digest naturallyoccurring prey species in the Gullmar fjord, Sweden. Digestion times were relatedto prey size and type, number of prey in the gut and size of the predator. Largeprey species or many prey in the gut resulted in longer digestion times comparedwith small or few prey, but digestion time also varied with the size of M. leidyi. Theprey- and predator-specific digestion times were used together with in situ preyconcentrations and gut contents of M. leidyi to calculate the clearance rates.Clearance rate as a function of ctenophore size is presented for the most abundantmesozooplankton: Acartia sp., Oithona sp., Oikopleura dioica and Penilia avirostris. Onthe basis of the relation between digestion time and the carbon content ratiobetween prey and predator, we discuss the possible effects of mixed prey assemblageson the estimates of clearance rates.
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| 6. |
- Jaspers, C., et al.
(författare)
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Reproduction rates under variable food conditions and starvation in Mnemiopsis leidyi: significance for the invasion success of a ctenophore
- 2015
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 37:5, s. 1011-1018
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Tidskriftsartikel (refereegranskat)abstract
- The ctenophore Mnemiopsis leidyi is characterized by high growth rates and a large reproductive capacity. However, reproductive dynamics are not yet well understood. Here, we present laboratory data on food-dependent egg production in M. leidyi and egg hatching time and success. Further, we report on the reproduction of laboratory-reared and field-caught animals during starvation. Our results show that the half-saturation zooplankton prey concentration for egg production is reached at food levels of 12-23 mu gC L-1, which is below the average summer food concentration encountered in invaded areas of northern Europe. Furthermore, starved animals continue to produce eggs for up to 12 days after cessation of feeding with high overall hatching success of 65-90%. These life history traits allow M. leidyi to thrive and reproduce in environments with varying food conditions and give it a competitive advantage under unfavourable conditions. This may explain why recurrent population blooms are observed and sustained in localized areas in invaded northern Europe, where water exchange is limited and zooplankton food resources are quickly depleted by M. leidyi. We suggest that these reproductive life history traits are key to its invasion success.
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| 7. |
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| 8. |
- Møller, Lene Friis
(författare)
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Amerikansk kammanet
- 2010
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Ingår i: Havsutsikt. ; :3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
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| 10. |
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