title: Biomass changes and trophic amplification of plankton in a warmer ocean.
abstract: Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 ± 0.05 °C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and regional models, imply the need for caution when extending these considerations into higher trophic levels.
authors.affiliation: AZTI-Tecnalia, Marine Research Division, Herrera kaia portualdea z/g, 20110, Pasaia, Spain.
authors.forename: Guillem
authors.initials: G
authors.lastname: Chust
authors.forename: J Icarus
authors.initials: JI
authors.lastname: Allen
authors.forename: Laurent
authors.initials: L
authors.lastname: Bopp
authors.forename: Corinna
authors.initials: C
authors.lastname: Schrum
authors.forename: Jason
authors.initials: J
authors.lastname: Holt
authors.forename: Kostas
authors.initials: K
authors.lastname: Tsiaras
authors.forename: Marco
authors.initials: M
authors.lastname: Zavatarelli
authors.forename: Marina
authors.initials: M
authors.lastname: Chifflet
authors.forename: Heather
authors.initials: H
authors.lastname: Cannaby
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dadou
authors.forename: Ute
authors.initials: U
authors.lastname: Daewel
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Wakelin
authors.forename: Eric
authors.initials: E
authors.lastname: Machu
authors.forename: Dhanya
authors.initials: D
authors.lastname: Pushpadas
authors.forename: Momme
authors.initials: M
authors.lastname: Butenschon
authors.forename: Yuri
authors.initials: Y
authors.lastname: Artioli
authors.forename: George
authors.initials: G
authors.lastname: Petihakis
authors.forename: Chris
authors.initials: C
authors.lastname: Smith
authors.forename: Veronique
authors.initials: V
authors.lastname: Garçon
authors.forename: Katerina
authors.initials: K
authors.lastname: Goubanova
authors.forename: Briac
authors.initials: B
authors.lastname: Le Vu
authors.forename: Bettina A
authors.initials: BA
authors.lastname: Fach
authors.forename: Baris
authors.initials: B
authors.lastname: Salihoglu
authors.forename: Emanuela
authors.initials: E
authors.lastname: Clementi
authors.forename: Xabier
authors.initials: X
authors.lastname: Irigoien
mesh_terms: D000818:Animals; D018533:Biomass; D057231:Climate Change; D017753:Ecosystem; D020387:Food Chain; D008962:Models, Theoretical; D009792:Oceans and Seas; D010933:Plankton / Q000502:physiology*; D013696:Temperature
keywords: ecosystem model; food web; plankton; primary production; sea warming; trophic amplification