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HABITAT SPECIALIZATION AND THE EXPLOITATION OF ALLOCHTHONOUS CARBON BY ZOOPLANKTON
Author(s) -
Matthews Blake,
Mazumder Asit
Publication year - 2006
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2006)87[2800:hsateo]2.0.co;2
Subject(s) - zooplankton , epilimnion , hypolimnion , ecology , habitat , daphnia pulex , environmental science , food web , daphnia , biology , ecosystem , eutrophication , nutrient
The significance of spatial subsidies depends on consumer resource interactions in the recipient habitat. Lakes are subsidized by terrestrial carbon sources, but the pathways of allochthonous carbon through lake food webs are complex and not well understood. Zooplankton vertically partition resources within stratified lakes in response to life history trade‐offs that are governed by predators, the quantity and quality of food, and abiotic conditions (e.g., UV, temperature, and viscosity). We measured habitat specialization of zooplankton in an oligotrophic lake where allochthonous and autochthonous resources varied with depth. During stratification, the quantity and quality of zooplankton food was highest in the hypolimnion. We used a yearlong time series of the δ 13 C of zooplankton and particulate organic matter (POM) to determine which zooplankton species exploited hypolimnetic rather than epilimnetic resources. Because the δ 13 C of POM decreased with depth, we used the δ 13 C of zooplankton to detect inter‐ and intraspecific variation in habitat selection. We incubated Daphnia pulex at discrete depths in the water column to confirm that the δ 13 C of zooplankton can indicate habitat specialization. Zooplankton that specialized in the epilimnion relied more on allochthonous carbon sources than those that specialized in the hypolimnion. Therefore, the fate of allochthonous carbon subsidies to lakes depends on spatially explicit consumer–resource interactions.