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| Javidpour, Jamileh; Molinero, Juan-carlos; Ramírez-romero, Eduardo; Roberts, Patrick; Larsen, Thomas. |
| The proliferation of invasive marine species is often explained by a lack of predators and opportunistic life history traits. For the invasive comb jelly Mnemiopsis leidyi, it has remained unclear how this now widely distributed species is able to overcome long periods of low food availability, particularly in their northernmost exotic habitats in Eurasia. Based on both field and laboratory evidence, we show that adult comb jellies in the western Baltic Sea continue building up their nutrient reserves after emptying the prey field through a shift to cannibalizing their own larvae. We argue, that by creating massive late summer blooms, the population can efficiently empty the prey field, outcompete intraguild competitors, and use the bloom events to build... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00628/74047/73454.pdf |
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| Wang, Yiming V.; Leduc, Guillaume; Regenberg, Marcus; Andersen, Nils; Larsen, Thomas; Blanz, Thomas; Schneider, Ralph R.. |
| Different proxies for sea surface temperature (SST) often exhibit divergent trends for deglacial warming in tropical regions, hampering our understanding of the phase relationship between tropical SSTs and continental ice volume at glacial terminations. To reconcile divergent SST trends, we report reconstructions of two commonly used paleothermometers (the foraminifera G. ruber Mg/Ca and the alkenone unsaturation index) from a marine sediment core collected in the southwestern tropical Indian Ocean encompassing the last 37,000 years. Our results show that SSTs derived from the alkenone unsaturation index (U-37(K)) are consistently warmer than those derived from Mg/Ca by similar to 2-3 degrees C except for the Heinrich Event 1. In addition, the initial... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Tropical Indian Ocean; Last Deglacial. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00291/40174/39037.pdf |
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| Larsen, Thomas. |
| This thesis investigated carbon and nitrogen dynamics of soil dwelling Collembola by using direct measurements and stable isotope additions. In an isotope change experiment, collembolans exchanged between 6 and 10% of carbon and nitrogen in their body tissue per day to metabolism and between 0.5 and 2% to reproduction. When collembolans on low and high protein diets were compared, animals on the low protein quality depleted their tissue 15N values relative to those on high quality diet indicating that the nitrogen turnover decreased on the low protein quality diet. In a wheat microcosm investigating source contributions from soil, roots and isotope labelled green manure the mixing model analysis indicated that photosynthate (root derived C) was the main... |
| Tipo: Thesis |
Palavras-chave: Nutrient turnover. |
| Ano: 2007 |
URL: http://orgprints.org/10585/1/10585.pdf |
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| Larsen, Thomas; Krogh, Paul Henning; Magid, Jakob; Hobbie, Erik; Marc, Ventura. |
| The study determined metabolic rates and elemental pools for two Collembola species with contrasting life histories. The fittest of the two species, P. minuta, excreted the equivalent of 10–12% of the elemental body content per day, and P. armata 7–10%. Most elements are lost to excretion (CO2 and N-waste). These figures in combination with stoichiometry and life histories indicate that the cost of P. minuta’s better fitness is a requirement for a higher quality diet than P. armata. The data produced in this study can be used to estimate the collembolan contribution to C and N fluxes in the soil. |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover. |
| Ano: 2006 |
URL: http://orgprints.org/9257/1/9257.pdf |
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