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Fjords are glacially over-deepened semi-enclosed marine basins, typically with entrance sills separating their deep waters from the adjacent coastal waters which restrict water circulation and thus oxygen renewal. The location of fjords is principally controlled by the occurrence of ice sheets, either modern or ancestral. Fjords are therefore geomorphological features that represent the transition from the terrestrial to the marine environment and, as such, have the potential to preserve evidence of environmental change. Typically, most fjords have been glaciated a number of times and some high-latitude fjords still possess a resident glacier. In most cases, glacial erosion through successive glacial/interglacial cycles has ensured the removal of sediment sequences within the fjord. Hence the stratigraphic record in fjords largely preserves a glacialdeglacial cycle of deposition over the last 18 ka or so. Sheltered water and high sedimentation rates have the potential to make fjords ideal depositional environments for preserving continuous records of climate and environmental change with high temporal resolution. In addition to acting as high-resolution environmental archives, fjords can also be thought of as mini-ocean sedimentary basin laboratories. Fjords remain an understudied and often neglected sedimentary realm. With predictions of warming climates, changing ocean circulation and rising sea levels, this volume is a timely look at these environmentally sensitive coastlines.

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A negative carbon isotope shift in sedimentary organic carbon deposited in stratified marine and lacustrine systems has often been inferred to be a consequence of the process of recycling of respired and, therefore, 13 C-depleted, dissolved inorganic carbon (DIC) formed from mineralization of descending organic matter. To study this process, we measured d 13 C DIC and d 13 C values of particulate organic carbon (POC) over an annual cycle in the permanently stratified Kyllaren fjord in Norway. A notable accumulation of respired DIC below the chemocline was evident from the substantially 13 Cdepleted DIC (ca. À19&). Especially in autumn to early spring, respired DIC from the deep anoxic water is mixed into the oxygenated surface water and the calculated respired DIC contribution to the total DIC pool was up to $40% in early spring in the upper 2 m of the water column. At 4 m depth, just below the chemocline, the respired DIC contribution reaches ca. 90% of the total DIC pool. Assimilation of the respired DIC seems to exert only a small effect on d 13 C POC , which has an average d 13 C value of À24&. The measured photoautotrophic fractionation (e p ) was low (<10&) during the majority of the year. This is likely responsible for reducing the apparent impact of recycling of respired DIC on d 13 C POC . However, in June 2002, photoautotrophic use of the 13 C-depleted DIC is obvious from a 13 C-depletion of POC (À33.7&) derived from a bloom of the protist Euglena sp.

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