Journal Article

Whole-lake carbon-13 additions reveal terrestrial support of aquatic food webs

Kritzberg, Emma S., Cole, Jonathan J., Bade, Darren L., Bastviken, David, Hodgson, James R., Carpenter, Stephen R., Van de Bogert, Matthew C., Pace, Michael L., Kitchell, James F.

2004

Overview

Ecosystems are supported by organic carbon from two distinct sources. Endogenous carbon is produced by photosynthesis within an ecosystem by autotrophic organisms. Exogenous carbon is produced elsewhere and transported into ecosystems. Consumers may use exogenous carbon with consequent influences on population dynamics, predator–prey relationships and ecosystem processes 1 . For example, exogenous inputs provide resources that may enhance consumer abundance beyond levels supported by within-system primary production 2 . Exogenous fluxes of organic carbon to ecosystems are often large, but this material is recalcitrant and difficult to assimilate, in contrast to endogenously produced organic matter, which is used more easily 3 , 4 . Here we show, by the experimental manipulation of dissolved inorganic 13 C in two lakes, that internal primary production is insufficient to support the food webs of these ecosystems. Additions of NaH 13 CO 3 enriched the 13 C content of dissolved inorganic carbon, particulate organic carbon, zooplankton and fish. Dynamics of 13 C indicate that 40–55% of particulate organic carbon and 22–50% of zooplankton carbon are derived from terrestrial sources, showing that there is significant subsidy of these ecosystems by organic carbon produced outside their boundaries.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Animal and plant ecology / Animal, plant and microbial ecology / Animals / Aquatic life / Biologi / Biological and medical sciences / Biological Sciences / Carbon / Carbon - metabolism / Carbon 13 / Carbon Isotopes / Daphnia - metabolism / Dissolved inorganic carbon / Ecology (including Biodiversity Conservation) / Ecosystems / Ekologi / Fishes - metabolism / Food / Food Chain / Food webs / Fresh Water - chemistry / Fresh Water - parasitology / Fresh water ecosystems / Freshwater / Fundamental and applied biological sciences. Psychology / Humanities and Social Sciences / Lakes / letter / Michigan / multidisciplinary / NATURAL SCIENCES / NATURVETENSKAP / Organic matter / Particulate organic carbon / Photosynthesis / Predator-prey interactions / Primary production / Science / Science (multidisciplinary) / Synecology / Zooplankton / Zooplankton - metabolism