9 eq.
1
Fig. 3.1. d13C distribution in ecosystems. Single arrows indicate CO2 fluxes. The double arrow signifies an equilibrium
isotope fractionation. Numbers for pools indicate d13C values (o/oo) and numbers of arrows indicated the fractionation
(D, o/oo) occurring during transfers. Negative d13C values indicate that less heavy isotope is present than in the standard
(which has a 1.1% 13C content; Table 1.2a), not that isotope concentrations are less than zero. From Peterson and Fry
(1987). Reprinted, with permission, from the Annual Review of Ecology and Systematics, Volume 18, copyright 1987 by
Annual Reviews www.annualreviews.org.
Fig. 3.2. Representative d15N values in natural systems. See Fig. 1.3a for explanation of symbols. From Peterson and Fry
(1987). Reprinted, with permission, from the Annual Review of Ecology and Systematics, Volume 18, copyright 1987 by
Annual Reviews www.annualreviews.org.
Fig. 3.3. Representative d34S values in natural systems. See Fig. 1.3a for explanation of symbols. From Peterson and
Fry (1987). Reprinted, with permission, from the Annual Review of Ecology and Systematics, Volume 18, copyright
1987 by Annual Reviews www.annualreviews.org.
Fig. 3.4. There are several stable isotope varieties of water, some of which are shown here. Heavy water 2H2H16O,
which is double-deuterated water or D2O, is very rare in nature, but can be produced in quantity in specialized
isotope-separation laboratories. D2O is a common laboratory solvent for nuclear magnetic resonance (NMR) studies
of chemical compounds.
Fig. 3.5. Three stable isotopes of oxygen (center) are present in common compounds (periphery) that circulate in the
biosphere.
Fig. 3.6. d15N values of algae in Moreton Bay, Australia where the city of Brisbane occupies the western shore. High d15N
values along the western shore indicate N pollution inputs from watershed rivers and local sewage treatment facilities.
The coastal pollution plumes are hard to identify by conventional measurements of ammonium and nitrate nutrients,
because tides rapidly disperse nutrients and algae use up the nutrients during growth in algal blooms of the region. But the
isotope values persist as nutrients are incorporated into the algae, tracing the nitrogen linkage to coastal inputs. Results are
contoured for macroalgae that were incubated 4 days in situ at approximately 100 sites in September 1997, then analyzed
for d15N (Costanzo et al. 2001). This d15N work continues now as a monitoring technique termed “sewage plume
mapping” (Costanzo et al. 2005). Reprinted from Marine Pollution Bulletin 42:149-156, S.D. Costanzo, M.J. O’Donohue,
W.C. Dennison, N.R. Loneragan, and M. Thomas, A new approach for detecting and mapping sewage impacts. Copyright
2001, with permission from Elsevier.
Fig. 3.7. d13C values of soils from six sites in Gabon, Africa where C4 savannah grasses (-12o/oo) and forest trees (-29o/oo)
contribute to soil organic matter. Low values near -29o/oo indicate landscapes dominated by forests, while high values
approaching -12o/oo indicate landscape-level shifts to open savannah. The square symbols give the isotope values for forest
soils in a reference undisturbed system that has not been invaded by savannah. Considering the isotope profiles of the other
non-reference soils as a history and reading from the bottom up, forests dominated the landscape until about 3000 years ago
when the landscape shifted to open savannah, but this trend reversed about 750 years ago, with forests now dominating
again. From: Delegue, M.-A., M. Fuhr, D. Schwartz, A. Mariotti and R. Nasi. 2001. Recent origin of a large part of the
forest cover in the Gabon coastal area based on stable carbon isotope data. Oecologia 129:106-113. This is reprint of Figure
2, p. 109 from the article and is used with permission from Springer.
Fig. 3.8. Effects of species introductions measured in
lake ecosystems. Introduction of nearshore bass species
forces the native top predator, lake trout, offshore.
Reflecting this spatial displacement, lake trout diets shift
towards feeding in a more pelagic food web (as
measured by lower d13C) and at a lower trophic level (as
measured by lower d15N; with d15N translated into the yaxis “trophic level” in this figure). Dietary shifts help
explain the decline of lake trout in the invaded lakes.
This figure summarizes results from comparative studies
in different lakes and results for single lakes studied over
time (from Vander Zanden et al. 1999; used with the
permission of the author and Nature Publishing Group.
Copyright 1999).
Fig. 3.9. Isotope map of North America
for precipitation dD values. Plant and
animal dD values reflect this continentallevel map. The map is reprinted from
Taylor, Jr., H.P., 1974, Economic Geology
69(6), p. 850, Fig. 6.
Fig. 3.10. dD values of feathers collected
from Wilson’s Warblers that overwintered
at sites from central America (10o N) to the
southern United States (35o N). Animals
collected farthest south at 10oN had the
lowest dD values, so that their point of
origin for the migration was in the far
north (see previous Fig. 3.9). These longdistance migrators moved past and leapfrogged over other populations that move
much less during their fall and winter
migrations (From: Kelly, J.F., V. Atudorei,
Z.D. Sharp and D.M. Finch. 2002. Insights
into Wilson’s Warbler migration from
analyses of hydrogen stable-isotope ratios.
Oecologia 130:216-221. This is a reprint of
Figure 6 on p. 219 of the article, used with
permission from Springer).
Fig. 3.11. Atmospheric CO2 records from 82.5oN at Alert, northerneastern Canada, part of a global monitoring network
for CO2 (http://cdiac.esd.ornl.gov/trends/co2/contents.htm; data shown are for the year 2000; you can access more data
for other years from this website and make your own plots).The CO2 concentrations decline during the summer growing
season (top left panel) when isotope fractionation during photosynthetic withdrawal of CO 2 leaves the residual
atmosphere enriched in 13C with higher d13C values (bottom left panel). An inverse technique that plots d13C vs. 1/CO2
concentration yields a y-intercept that is the isotope value of the source dominating the CO 2 dynamics, in this case 28.2o/oo carbon from C3 plants (middle right panel).