5: Take-home messages
- Page ID
- 25881
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- The census of biomass distribution (≈550 Gt C) on Earth provides an integrated global picture of the relative and absolute abundances of all kingdoms of life: plants (≈450 Gt C), bacteria (≈70 Gt C), archaea (≈7 Gt C), and animals (≈2 Gt C) ;
- Terrestrial biomass is about two orders of magnitude higher than marine biomass, and a total of ≈6 Gt C is estimated in marine organisms;
- Plant biomass (which dominates the biosphere) is mostly located on land; it accounts for less than 10% of the total biomass in the ocean.
- Animals, protists, and bacteria together account for ≈80% of marine biomass, whereas on land they account for only ≈2%.
- The animal biomass is predominantly marine; it consists of small mesopelagic fish and crustaceans, mainly copepods, shrimp, and krill.
- The marine environment is primarily occupied by microbes, primarily bacteria and protists, which account for ≈70% of the total marine biomass. The remaining ≈30% is primarily composed of arthropods and fish.
- Viruses dominate the ocean in terms of numbers but constitute only ≈1% of the total biomass.
- The deep subsurface holds ≈15% of the total biomass of the biosphere. It is mainly composed of bacteria and archaea.
- The global marine biomass pyramid contain much more consumers (≈5 Gt C) than producers (≈1 Gt C). Conversely, on land, the biomass of primary producers (≈450 Gt C) is much larger than that of primary and secondary consumers (≈20 Gt C).
- The mass of humans is an order of magnitude greater than that of all wild mammals combined.
- Humans have had a historical impact on the overall biomass of most important taxa, namely:
- The huge decrease in total biomass of wild animals, including fish;
- The gain in total mammalian biomass due to livestock husbandry;
- The profound reshaping in the total quantity of carbon sequestered by plants.
- The main gaps in our knowledge concern the distribution of biomass among different microbial taxa, such as bacteria, archaea, protists and fungi.
- Our knowledge of the biomass composition of the different taxa is mainly determined by our ability to sample, for example, in deep marine subsurface environments.