Natural high pCO2 increases autotrophy in Anemonia viridis (Anthozoa) as revealed from stable isotope (C, N) analysis

Contemporary cnidarian-algae symbioses are challenged by increasing CO2 concentrations (ocean warming and acidification) affecting organisms' biological performance. We examined the natural variability of carbon and nitrogen isotopes in the symbiotic sea anemone Anemonia viridis to investigate dietary shifts (autotrophy/heterotrophy) along a natural pCO2 gradient at the island of Vulcano, Italy. delta 13C values for both algal symbionts (Symbiodinium) and host tissue of A. viridis became significantly lighter with increasing seawater pCO2. Together with a decrease in the difference between delta 13C values of both fractions at the higher pCO2 sites, these results indicate there is a greater net autotrophic input to the A. viridis carbon budget under high pCO2 conditions. delta 15N values and C/N ratios did not change in Symbiodinium and host tissue along the pCO2 gradient. Additional physiological parameters revealed anemone protein and Symbiodinium chlorophyll a remained unaltered among sites. Symbiodinium density was similar among sites yet their mitotic index increased in anemones under elevated pCO2. Overall, our findings show that A. viridis is characterized by a higher autotrophic/heterotrophic ratio as pCO2 increases. The unique trophic flexibility of this species may give it a competitive advantage and enable its potential acclimation and ecological success in the future under increased ocean acidification.

Pollen profile Tegeler See, Brandenburg, Germany

The region D-s (Fig. 15.8) belongs to the Weichselian glaciated area of the North German lowlands and is a section of the older part of the young moraine landscape. The Warsaw-Berlin Urstromtal with the Spree River and the Havel lake-river system subdivide the region into four subregions, including a northern, southern and western ground moraine plateau. The region as a whole comprises the former West-Berlin, surrounded by the late GDR.

Pollen records of five sediment cores from northern Germany

Within a larger program research work is being done on the history of settlement and landscape of the 'Siedlungskammer' Flögeln and the adjacent area. The 'Siedlungskammer' consists of an isolated pleistocene sand ground (Geest-island) surroundet by bogs. Starting from the edge of the Geest, near which large-scale archaeological excavations are carried out, three raised bog profiles were taken at 300, 500 and 4000 m off the prehistoric settlement. They were investigated by means of pollen analysis, and reflect in a decreasing way the activities of man on the Geestisland. Another pollen diagram from the nearby fen peat was worked out for comparison. At the same time it helped to date back a prehistoric sand path to the Roman period. The pollen diagrams cover the vegetational history without gaps from the early Atlantic period to modern times. The vegetation was decisively determined by the poor soils of this area. T'he pollen diagrams give evidence of the activity of settlers since the Neolithic age, with some gaps in the beginning, but later continuously from the middle of the Bronze age until the early migration period. The influence of the nearby settlement, which existed from the Birth of Christ to the 4/5th century, comes out distinctly. Among the cereals which were then cultivated here, there also was rye, at least in the 4/5th century, but most probably already during the Roman period. Besides that people cultivated barley, oats, and flax. The settlement break during the so-called dark ages between the 4/5th century and the time about 800 A.D. was confirmed by pollen analysis. During this time the area was once more covered by forests. The fluctuations of man's activities during the late Middle Ages and modern times, as they are made visible by pollen analysis, correspond to historically wellknown developments.