Carbon Fixation Trends in Eleven of the World’s Largest Lakes: 2003–2018

Michael Sayers,Gary Fahnenstiel,Karl Bosse,Robert Shuchman

doi:10.3390/w12123500

Abstract

Large freshwater lakes provide immense value to the surrounding populations, yet there is limited understanding of how these lakes will respond to climate change and other factors. This study uses satellite remote sensing to estimate annual, lake-wide primary production in 11 of the world’s largest lakes from 2003–2018. These lakes include the five Laurentian Great Lakes, the three African Great Lakes, Lake Baikal, and Great Bear and Great Slave Lakes. Mean annual production in these lakes ranged from under 200 mgC/m2/day to over 1100 mgC/m2/day, and the lakes were placed into one of three distinct groups (oligotrophic, mesotrophic, or eutrophic) based on their level of production. The analysis revealed only three lakes with significant production trends over the study period, with increases in Great Bear Lake (24% increase over the study period) and Great Slave Lake (27%) and a decline in Lake Tanganyika (−16%). These changes appear to be related to climate change, including increasing temperatures and solar radiation and decreasing wind speeds. This study is the first to use consistent methodology to study primary production in the world’s largest lakes, allowing for these novel between-lake comparisons and assessment of inter-annual trends.

Highlights

Freshwater lakes make up less than 1% of the total global water volume [1], yet they provide tremendous value to the planet and the nearby human populations
While the number of global lakes has been estimated to be in the hundreds of millions [2,3], lakes are unevenly distributed in size, with the five largest lakes containing more than half the planet’s liquid fresh water [4]. These large lakes provide many important services to the surrounding human populations, both socially and economically. This is true for the lakes in more populous regions, including the African Great Lakes (Lakes Malawi, Tanganyika, and Victoria) and Laurentian Great Lakes (Lakes Erie, Huron, Michigan, Ontario, and Superior)
This study investigates primary production in 11 of the world’s largest lakes, including: Lake Baikal; the African Great Lakes (Lakes Malawi, Tanganyika, and Victoria); two near-arctic lakes

Summary

Introduction

Freshwater lakes make up less than 1% of the total global water volume [1], yet they provide tremendous value to the planet and the nearby human populations. While the number of global lakes has been estimated to be in the hundreds of millions [2,3], lakes are unevenly distributed in size, with the five largest lakes containing more than half the planet’s liquid fresh water [4]. These large lakes provide many important services to the surrounding human populations, both socially and economically. Large lakes provide tremendous economic value through recreation and tourism; this industry has been estimated to bring in over USD 6 billion dollars annually in the Laurentian Great Lakes [4]. In addition to the clear social and economic value these lakes provide to the local populations, these lakes are an important part of the global carbon cycle [7,8,9], their total contribution in terms of carbon fixation is not well understood

Results

Discussion

Conclusion