Abstract. CO 2 emissions are leading to an acidification of the oceans. Predicting marine community vulnerability towards acidification is difficult, as adaptation processes cannot be accounted for in most experimental studies. Naturally CO 2 enriched sites thus can serve as valuable proxies for future changes in community structure. Here we describe a natural analogue site in the Western Baltic Sea. Seawater pCO 2 in Kiel Fjord is elevated for large parts of the year due to upwelling of CO 2 rich waters. Peak pCO 2 values of >230 Pa (>2300 µatm) and pH NBS values of <7.5 are encountered during summer and autumn, average pCO 2 values are ∼70 Pa (∼700 µatm). In contrast to previously described naturally CO 2 enriched sites that have suggested a progressive displacement of calcifying auto-and heterotrophic species, the macrobenthic community in Kiel Fjord is dominated by calcifying invertebrates. We show that blue mussels from Kiel Fjord can maintain control rates of somatic and shell growth at a pCO 2 of 142 Pa (1400 µatm, pH NBS = 7.7). Juvenile mussel recruitment peaks during the summer months, when high water pCO 2 values of ∼100 Pa (∼1000 µatm) prevail. Our findings indicate that calcifying keystone species may be able to cope with surface ocean pH NBS values projected for the end of this century when food supply is sufficient. However, owing to non-linear synergistic effects of future acidification and upwelling of corrosive water, peak seawater pCO 2 in Kiel Fjord and many other productive estuarine habitats could increase to values >400 Pa (>4000 µatm). These changes will most likely affect calcification and recruitment, and increase external shell dissolution.

CO₂ emissions are leading to an acidification of the oceans. Predicting marine community vulnerability towards acidification is difficult, as adaptation processes cannot be accounted for in most experimental studies. Naturally CO₂ enriched sites thus can serve as valuable proxies for future changes in community structure. Here we describe a natural analogue site in the Western Baltic Sea. Seawater pCO₂ in Kiel Fjord is elevated for large parts of the year due to upwelling of CO₂ rich waters. Peak pCO₂ values of >230 Pa (>2300 μatm) and pH values of <7.5 are encountered during summer and autumn, average pCO₂ values are ~70 Pa (~700 μatm). In contrast to previously described naturally CO₂ enriched sites that have suggested a progressive displacement of calcifying auto- and heterotrophic species, the macrobenthic community in Kiel Fjord is dominated by calcifying invertebrates. We show that blue mussels from Kiel Fjord can maintain control rates of somatic and shell growth at a pCO₂ of 142 Pa (1400 μatm, pH=7.7). Juvenile mussel recruitment peaks during the summer months, when high water pCO₂ values of ~100 Pa (~1000 μatm) prevail. Our findings indicate that calcifying keystone species may be able to cope with surface ocean pH values projected for the end of this century. However, owing to non-linear synergistic effects of future acidification and upwelling of corrosive water, peak seawater pCO₂ in Kiel Fjord and many other productive estuarine habitats could increase to values >400 Pa (>4000 μatm). These changes will most likely affect calcification and recruitment, and increase external shell dissolution

Specific immune priming enables an induced immune response upon repeated pathogen encounter. As a functional analogue to vertebrate immune memory, such adaptive plasticity has been described, for instance, in insects and crustaceans. However, towards the base of the metazoan tree our knowledge about the existence of specific immune priming becomes scattered. Here, we exposed the invasive ctenophore Mnemiopsis leidyi repeatedly to two different bacterial epitopes (Gram-positive or -negative) and measured gene expression. Ctenophores experienced either the same bacterial epitope twice (homologous treatments) or different bacterial epitopes (heterologous treatments). Our results demonstrate that immune gene expression depends on earlier bacterial exposure. We detected significantly different expression upon heterologous compared with homologous bacterial treatment at three immune activator and effector genes. This is the first experimental evidence for specific immune priming in Ctenophora and generally in non-bilaterian animals, hereby adding to our growing notion of plasticity in innate immune systems across all animal phyla.

Animal-free (AF) SERVA Collagenase AF-1 and Neutral Protease (NP) AF GMP Grade have recently become available for human islet isolation. This report describes the initial experiences of 3 different islet transplant centers. Thirty-four human pancreases were digested using 1 vial of the 6 different lots of Collagenase AF-1 (2,000–2,583 PZ-U/vial) supplemented with 4 different lots of NP AF in a range of 50 to 160 DMC-U per pancreas. Isolation, culture, and quality assessment were performed using standard techniques as previously described. All data are presented as mean ± standard error of the mean (SEM). Variability of pancreas weight was associated with a wide range of collagenase and NP activities, ranging from 12.7 to 46.6 PZ-U/g (26.0 ± 1.5 PZ-U/g) and 0.4 to 3.0 DMC-U/g (1.5 ± 0.1 DMC-U/g), respectively. Postpurification islet yield was 296,494 ± 33,620 islet equivalents (IEQ) equivalent to 3,274 ± 450 IEQ/g with a purity of 55.9% ± 3.2%. Quality assessment performed after 2 to 4 d of culture demonstrated a viability of 88.1% ± 1.5% and a stimulation index of 3.7 ± 0.7. Eighteen of the 34 preparations were transplanted into type 1 diabetic patients equivalent to a transplantation rate of 52.9%. Six preparations, which were infused into patients as first transplant, could be analyzed and increased the fasting C-peptide level from 0.11 ± 0.08 pretransplant to 1.23 ± 0.24 and 2.27 ± 0.31 ng/mL 3 and 6 mo posttransplant (P < 0.05), respectively. Insulin requirements were simultaneously reduced at the same time from 39.2 ± 3.8 IU/d before transplantation to 10.8 ± 4.1 and 4.0 ± 2.3 IU/d, after 3 and 6 mo posttransplant (P < 0.05), respectively. This study demonstrates the efficiency of AF SERVA Collagenase AF-1 and NP AF for clinical islet isolation and transplantation. The new plant-based production process makes these products a safe new option for the islet field.

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