The German zoologist and paleontologist Ludwig Heinrich Philip Döderlein (1855–1936) was one of the foremost echinoderm researchers of his time. Self-taught in many subjects of natural science, he rose from provincial obscurity to international fame. We present some aspects of: a) his life history; b) his echinoderm research; c) his contributions to ecology and evolutionary biology, with the coral genus Fungia as an example; and d) his achievements in building up and promoting biological collections. The latter is illustrated by the Bavarian State Collection of Zoology, being second only to the Zoological Museum of Strasbourg in the diversity of Döderlein specimens that survived the perils of two world wars.
Abstract. Lipid remodeling, the modification of cell membrane chemistry via structural rearrangements within the lipid pool of an organism, is a common physiological response amongst all domains of life to alleviate environmental stress and maintain cellular homeostasis. Whereas culture experiments and environmental studies of phytoplankton have demonstrated the plasticity of lipids in response to specific abiotic stressors, few analyses have explored the impacts of multi-environmental stressors at the community-level scale. Here, we study changes in the pool of intact polar lipids (IPLs) of a phytoplanktonic community exposed to multi-environmental stressors during a ∼ 2-month-long mesocosm experiment deployed in the eastern tropical South Pacific off the coast of Callao, Peru. We investigate lipid remodeling of IPLs in response to changing nutrient stoichiometries, temperature, pH, and light availability in surface and subsurface water masses with contrasting redox potentials, using multiple linear regressions, classification and regression trees, and random forest analyses. We observe proportional increases in certain glycolipids (namely mono- and diglycosyldiacylglycerol – MGDG and DGDG, respectively) associated with higher temperatures and oxic conditions, consistent with previous observations of their utility to compensate for thermal stress and their degradation under oxygen stress. N-bearing (i.e., betaine lipids and phosphatidylethanolamine – BLs and PE) and non-N-bearing (i.e., MGDG; phosphatidylglycerol, PG; and sulfoquinovosyldiacylglycerol, SQDG) IPLs are anti-correlated and have strong positive correlations with nitrogen-replete and nitrogen-depleted conditions, respectively, which suggests a substitution mechanism for N-bearing IPLs under nitrogen limitation. Reduced CO2(aq) availability and increased pH levels are associated with greater proportions of DGDG and SQDG IPLs, possibly in response to the lower concentration of CO2(aq) and the overall lower availability of inorganic carbon for fixation. A higher production of MGDG in surface waters corresponds well with its established photoprotective and antioxidant mechanisms in thylakoid membranes. The observed statistical relationships between IPL distributions, physicochemical parameters, and the composition of the phytoplankton community suggest evidence of lipid remodeling in response to environmental stressors. These physiological responses may allow phytoplankton to reallocate resources from structural or extrachloroplastic membrane lipids (i.e., phospholipids and betaine lipids) under high-growth conditions to thylakoid and/or plastid membrane lipids (i.e., glycolipids and certain phosphatidylglycerols) under growth-limiting conditions. Further investigation of the exact mechanisms controlling the observed trends in lipid distributions is necessary to better understand how membrane reorganization under multi-environmental stressors can affect the pools of cellular C, N, P, and S, as well as their fluxes to higher trophic levels in marine environments subjected to increasing environmental pressure. Our results suggest that future studies addressing the biogeochemical consequences of climate change in the eastern tropical South Pacific Ocean must take into consideration the impacts of lipid remodeling in phytoplankton.
Abstract Im Jahre 2009 feiern wir in den Lebenswissenschaften neben dem Darwin‐Jahr auch weitere Jubiläen. Der 90. Geburtstag von Professor Hans Hass (*1919) ist Anlass dieses Artikels. Hans Hass wird oft als “Tauchpionier” bezeichnet, eine dem Jubilar nicht vollständig gerecht werdende Bezeichnung. Sein Lebenswerk umfasst mehr als 100 Filme und 30 Bücher.
