Coastal food web structure, carbon storage, and nitrogen retention regulated by consumer pressure and nutrient loading.

Worm, Boris, Lotze, Heike and Sommer, Ulrich (2000) Coastal food web structure, carbon storage, and nitrogen retention regulated by consumer pressure and nutrient loading. Limnology and Oceanography, 45 (2). pp. 339-349. DOI 10.4319/lo.2000.45.2.0339.

[img] Text
Worm.pdf - Published Version
Restricted to Registered users only

Download (160Kb) | Contact

Supplementary data:

Abstract

By factorial field experiments we analyzed the relative effects of increased nutrient (N+P) loading and natural grazing pressure on species composition, carbon storage, and nitrogen retention in the Baltic Sea littoral food web, composed of macroalgae, grazers (snails, isopods, amphipods), and predators (shrimps, crabs, fish). Nitrogen was depleted relative to phosphorus throughout most of the year. Increasing nitrogen (6–200% over ambient concentrations) enhanced algal productivity and cover of fast-growing annual algae, grazer, and predator densities, suggesting a three-level bottom-up effect. With increasing nitrogen loading, annual algae increasingly blocked perennial algal recruitment (65–98% decrease) and growth. Grazers counteracted the effects of nutrient enrichment on algal species composition through selective consumption of annual algae. Grazer exclusion had equivalent negative effects on perennial recruitment as a 85% increase in nitrogen loading. Nutrient enrichment increased algal nitrogen content and decreased tissue C: N ratios in spring and summer but not in fall. Carbon storage and nitrogen retention, measured as C and N retained in plant biomass at the end of the growth season, were increased by grazers (C: 39%, N: 24%) but decreased with increasing nitrogen loading (C: -71%, N: -74%). Our results emphasize the important role of grazers in buffering moderate eutrophication effects and illustrate how food web interactions and shifts in species composition are tightly linked to coastal ecosystem function

Document Type: Article
Keywords: Food Webs; coastal ecosystem function
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-N Experimental Ecology - Food Webs
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.4319/lo.2000.45.2.0339
ISSN: 0024-3590
Date Deposited: 27 Mar 2012 06:05
Last Modified: 25 Jun 2018 13:34
URI: http://oceanrep.geomar.de/id/eprint/14106

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...