Goose-mediated nutrient enrichment and planktonic grazer control in arctic freshwater ponds

A dramatic increase in the breeding population of geese has occurred over the past few decades at Svalbard. This may strongly impact the fragile ecosystems of the Arctic tundra because many of the ultra-oligotrophic freshwater systems experience enrichment from goose feces. We surveyed 21 shallow tu...

Full description

Bibliographic Details
Published in:Oecologia
Main Authors: Van Geest, G. J., Hessen, D. O., Spierenburg, P., Dahl-Hansen, G. A. P., Christensen, G., Faerovig, P. J., Brehm, M., Loonen, M. J. J. E., Van Donk, E.
Format: Article in Journal/Newspaper
Language:English
Published: 2007
Subjects:
Daphnia
plankton
top-down control
trophic cascades
FOOD-WEB INTERACTIONS
ALGAL BIOMASS
ZOOPLANKTON COMMUNITIES
MOUNTAIN LAKES
DAPHNIA GROWTH
CLIMATE-CHANGE
PHYTOPLANKTON
LIMITATION
PHOSPHORUS
NITROGEN
Arctic
Svalbard
Climate change
Phytoplankton
Tundra
Zooplankton
Online Access:https://hdl.handle.net/11370/8505305a-7fbf-48d6-b5b9-8b66c0d8ec80
https://research.rug.nl/en/publications/8505305a-7fbf-48d6-b5b9-8b66c0d8ec80
https://doi.org/10.1007/s00442-007-0770-7
https://pure.rug.nl/ws/files/63047102/Goose_mediated_nutrient_enrichment.pdf
Description
Summary:A dramatic increase in the breeding population of geese has occurred over the past few decades at Svalbard. This may strongly impact the fragile ecosystems of the Arctic tundra because many of the ultra-oligotrophic freshwater systems experience enrichment from goose feces. We surveyed 21 shallow tundra ponds along a gradient of nutrient enrichment based on exposure to geese. Concentrations of total phosphorus (P) and dissolved inorganic nitrogen (DIN) in the tundra ponds ranged from 2-76 to 2-23 mu g l(-1) respectively, yet there was no significant increase in phytoplankton biomass (measured as chlorophyll a; range: 0.6-7.3 mu g l(-1)) along the nutrient gradient. This lack of response may be the result of the trophic structure of these ecosystems, which consists of only a two-trophic level food chain with high biomasses of the efficient zooplankton grazer Daphnia in the absence of fish and scarcity of invertebrate predators. Our results indicate that this may cause a highly efficient grazing control of phytoplankton in all ponds, supported by the fact that large fractions of the nutrient pools were bound in zooplankton biomass. The median percentage of Daphnia-N and Daphnia-P content to particulate (sestonic) N and P was 338 and 3009%, respectively, which is extremely high compared to temperate lakes. Our data suggest that Daphnia in shallow arctic ponds is heavily subsidized by major inputs of energy from other food sources (bacteria, benthic biofilm), which may be crucial to the persistence of strong top-down control of pelagic algae by Daphnia.

Similar Items