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Benthic algae compensate for phytoplankton losses in large aquatic ecosystems
Author(s) -
Brothers Soren,
Vadeboncoeur Yvonne,
Sibley Paul
Publication year - 2016
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.13306
Subject(s) - benthic zone , phytoplankton , environmental science , ecosystem , trophic level , biomass (ecology) , ecology , productivity , primary producers , eutrophication , aquatic ecosystem , autotroph , oceanography , lake ecosystem , nutrient , biology , geology , genetics , bacteria , economics , macroeconomics
Abstract Anthropogenic activities can induce major trophic shifts in aquatic systems, yet we have an incomplete understanding of the implication of such shifts on ecosystem function and on primary production ( PP ) in particular. In recent decades, phytoplankton biomass and production in the Laurentian Great Lakes have declined in response to reduced nutrient concentrations and invasive mussels. However, the increases in water clarity associated with declines in phytoplankton may have positive effects on benthic PP at the ecosystem scale. Have these lakes experienced oligotrophication (a reduction of algal production), or simply a shift in autotrophic structure with no net decline in PP ? Benthic contributions to ecosystem PP are rarely measured in large aquatic systems, but our calculations based on productivity rates from the Great Lakes indicate that a significant proportion (up to one half, in Lake Huron) of their whole‐lake production may be benthic. The large declines (5–45%) in phytoplankton production in the Great Lakes from the 1970s to 2000s may be substantially compensated by benthic PP , which increased by up to 190%. Thus, the autotrophic productive capacity of large aquatic ecosystems may be relatively resilient to shifts in trophic status, due to a redirection of production to the near‐shore benthic zone, and large lakes may exhibit shifts in autotrophic structure analogous to the regime shifts seen in shallow lakes.