Ecosystem models often use wet weights to parameterise biota disregarding their water content. This may be especially erroneous for gelatinous plankton, such as salps and pyrosomes, with high, compared to crustaceans, water content. Poorly quantified residual water should also be corrected when using dry weights for parameterisation. We estimated the residual water content (as well as elemental and organic contents) for seven tunicate species, one pyrosome and six salps (N = 107). Specimens were collected during several research expeditions in the Southern Ocean, the Northeast Pacific, east of New Zealand, and around Hawaii between 2004 and 2021. The residual water content of tunicates was analyzed for inter- and intraspecific variability. The H-surplus method (Madin et al. 1981) was applied for the residual water content calculation. The dataset contains information about the life cycle stage (blastozooid versus oozooid), tissue type (tunic versus whole organism), drying method (oven versus freeze-drying), size, and the elemental and organic contents of the samples. The methods and results of the study are described in detail in Lüskow et al. (submitted).
The palsa and lithalsa are reliable indicators of the presence of permafrost, especially on its southern border. The subject of the study is the consideration of the C/N ratio in the peat of the palsa and the soil and humus horizon of the lithalsa as a criterion for the separation of the palsa and lithalsa. The palsas near the Eletskaya settlement in the Bolshezemelskaya tundra and the lithalsas in the Southern Transbaikalia near the Preobrazhenka village and in the valley of the Sentsa in the Eastern Sayan are considered. Included in the discussion is the background of lithalsa and palsa research in Russia at the start of the 20th century. It was found that the nitrogen content in the surface layers of the lithalsa (0.45-1.73% in the valley of the Sentsa River and 0.47-2.01% near the Arachley Lake) is approximately in the same range as in the surface horizons of the palsa, regardless of the permafrost region. The results of the carbon and nitrogen content determination, as well as their ratios in the peat cover of the palsa, are summarized. In contrast to the lithalsa, the carbon content in the peat horizons of the palsa and flat-hummock peatlands is many times higher than the values obtained for both surface and buried organic horizons of the lithalsa. The value of C/N less than 13 has not been recorded for the peat cover of palsa; this indicator for lithalsa never exceeds 10-12.
Im Rahmen des Projektes 'Südargentinische Seesediment Archive und Modellierung' (SALSA) sollen limnische Sedimente aus Kraterseen des südlichen Patagoniens, Argentinien (52 Grad S) untersucht werden. SALSA ist ein interdisziplinäres Forschungsprojekt, dass sich zum Ziel gesetzt hat, die instrumentell erfasste Klimageschichte Südamerikas mit quantitativen Proxi-Daten auf einer präzisen Zeitskala zurückzuschreiben, um natürliche Klimavariabilitäten während des Holozäns hochauflösend (mindestens mit dekadischer zeitlicher Auflösung) zu dokumentieren und zu interpretieren. Im Rahmen dieses Verbundprojektes soll die Entwicklung von prozessorientierten Transferfunktionen über bio- und geowissenschaftliche Proxi-Daten vorangetrieben werden, um das Verständnis der klima-steuernden Faktoren, ihrer Kontrollmechanismen und ihrer Auswirkungen auf das natürliche Umweltarchiv 'See' in den hohen Breiten der südlichen Hemisphäre besser verstehen zu können. Dies beinhaltet auch die Ableitung von quantitativen paläoklimatischen Parametern (z.B. Temperatur) mit höchstmöglicher zeitlicher Auflösung für das Holozän und das Spätweichsel als Eingabeparameter für regionale Klimamodelle und letztlich auch für globale Klimamodelle. Weitere Informationen unter: http://www.salsa.uni-bremen.de.