Table Of ContentNEW PERSPECTIVES ON NITROGEN CYCLING IN
THE TEMPERATE AND TROPICAL AMERICAS
NEW PERSPECTIVES ON
NITROGEN CYCLING IN
THE TEMPERATE AND
TROPICAL AMERICAS
Report of the International SCOPE Nitrogen Project
Edited by
ALAN R. TOWNSEND
University of Colorado, Boulder, Colorado, U.S.A.
Reprinted from Biogeochemistry
Volume 46, Nos. 1-3 (1999)
SPRINGER SCIENCE+BUSINESS MEDIA, B.V.
A C.I.P. catalogue record for this book is available from the Library of Cougress.
ISBN 978-94-010-5961-9 ISBN 978-94-011-4645-6 (eBook)
DOI 10.1007/978-94-011-4645-6
Printed an acid-frec paper.
Ali Rights Reserved
©1999 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 1999
Softcover reprint of the hardcover 1s t edition 1999
No part of the material protected by this copyright notice may be reproduced or
utilized in any form or by any means, electronic or mechanical,
including photocopying, recording or by any information storage and
rctricval systcm, without written permission from the copyright owner.
Table of Contents
furewo~ 1~
International Scope Project 4
JORGE E. CORREDOR / NLTpoV - An etymology of nitrogen
~~~~~~~~ ~6
ELISABETH A. HOLLAND, FRANK J. DENTENER, BOBBY
H. BRASWELL & JAMES M. SULZMAN / Contemporary
and pre-industrial global reactive nitrogen budgets 7-43
L.A. MARTINELLI, M.e. PICCOLO, A.R. TOWNSEND,
P.M. VITOUSEK, E. CUEVAS, W McDOWELL, G.P.
ROBERTSON, O.e. SANTOS & K. TRESEDER / Nitrogen
stable isotopic composition of leaves and soil: Tropical versus
temperate forests 45-65
PAMELA A. MATSON, WILLIAM H. McDOWELL, ALAN
R. TOWNSEND & PETER M. VITOUSEK / The global
ization of N deposition: ecosystem consequences in tropical
environments 67-83
TAMARA J. CHESTNUT, DANIEL J. ZARIN, WILLIAM H.
McDOWELL & MICHAEL KELLER / A nitrogen budget for
late-successional hillslope tabonuco forest, Puerto Rico 85-108
J.A. DOWNING, M. McCLAIN, R. TWILLEY, J.M. MELACK,
J. ELSER, N.N. RABALAIS, WM. LEWIS, JR., R.E.
TURNER, J. CORREDOR, D. SOTO, A. YANEZ
ARANCIBIA, J.A. KOPASKA & R.W HOWARTH / The
impact of accelerating land-use change on the N-Cycle of
tropical aquatic ecosystems: Current conditions and projected
changes 109-148
vi
WILLIAM M. LEWIS, JR., JOHN M. MELACK, WILLIAM
H. McDOWELL, MICHAEL McCLAIN & JEFFREY E.
RICHEY / Nitrogen yields from undisturbed watersheds in the
Americas 149-162
JORGE E. CORREDOR, ROBERT W. HOWARTH, ROBERT
R. TWILLEY & JULIO M. MORELL / Nitrogen cycling and
anthropogenic impact in the tropical inter american seas 163-178
PETER M. VITOUSEK & CHRISTOPHER B. FIELD / Ecosys
tem constraints to symbiotic nitrogen fixers: a simple model and
its implications 179-202
ROBERT W. HOWARTH, FRANCIS CHAN & ROXANNE
MARINO / Do top-down and bottom-up controls interact to
exclude nitrogen-fixing cyanobacteria from the plankton of
estuaries? An exploration with a simulation model 203-231
TIMOTHY E. CREWS / The presence of nitrogen fixing
legumes in terrestrial communities: Evolutionary vs ecological
considerations 233-246
DAVID U. HOOPER & LORETTA JOHNSON / Nitrogen limita
tion in dryland ecosystems: Responses to geographical and
temporal variation in precipitation 247-293
Biogeochemistry 46: 1-3, 1999.
© 1999 Kluwer Academic Publishers.
Foreword
The papers in this special issue grew out of a workshop held in Termas de
Chili an, Chile, in December of 1996. This was the fourth of a series of work
shops that comprise the core activities of the International SCOPE Project on
Nitrogen Transport and Transformations: A Regional and Global Analysis;
the first of these workshops also resulted in a special issue of this journal
(Biogeochemistry 35(1): 1996). The Chilean workshop's central purposes
were to compare nitrogen cycling in the relatively pristine temperate South
Americas with the generally more polluted temperate North Americas, and
to compare both with nitrogen cycling in the tropical Americas. More than
40 scientists from 12 different countries helped make this meeting a success,
and their enthusiasm for the ideas generated during the meeting carried over
into the production of the twelve manuscripts included in this volume. It is
my belief that these manuscripts are rich in exciting new ideas and theory; I
hope the readers of Biogeochemistry share this opinion.
The first contribution in this issue is by Jorge Corredor; he provides a brief
but enlightening and appropriate history of the word nitrogen. As he points
out, many of us use nitrogen and related words on a near-daily basis, yet
few of us know their etymology. The next paper is by Elisabeth Holland and
colleagues; they synthesize data on N deposition and N emissions as well as
use a global model of tropospheric chemistry and transport (MOGUNTIA)
to provide an updated view of reactive N exchanges between the terrestrial
biosphere and the atmosphere.
The next nine papers can be thought of as three somewhat distinct sections
of this volume. The first three of these nine all focus on N cycling in terrestrial
ecosystems, with an emphasis on the moist tropics. Luiz Martinelli et al.
present data on lsN values of both foliage and soils from a variety of trop
ical and temperate forests, including forests along a soil age gradient in the
Hawaiian Islands. They show substantial differences in 15N patterns between
temperate and tropical systems, and argue that these isotopic data provide
time-integrated evidence that N cycles in relative excess in many tropical
forests. Pamela Matson and colleagues then present a theoretical analysis of
2
how moist tropical forests may respond to increasing N deposition in the next
few decades; they contend that the naturally N-rich state of these systems
will lead to substantially different responses to increasing N additions than
has been seen in the temperate zone. Finally, Tamara Chestnut and co-authors
present a nitrogen budget for hillslope tabonuco forest stands in Puerto Rico;
such budgets for tropical systems are both rare and sorely needed.
The next three papers address N cycling in aquatic ecosystems, again with
a focus on the tropics. John Downing and the other members of the aquatic
working group from Chillan examine how land use and land cover changes
in the tropics may affect N cycling in both freshwater and coastal marine
ecosystems. They conclude their analyses with the hypothesis that alterations
to the nitrogen cycle will affect tropical aquatic systems to an even greater
extent than what has already been seen in the temperate zone. Bill Lewis
and co-authors then summarize N export from thirty-one relatively pristine
watersheds, thereby providing valuable information on the baseline condi
tions against which we can assess anthropogenic effects on the N cycle. They
focus on the tropics, but present data from a few temperate watersheds as
well, and show that N yields and concentrations in the tropical systems are
much greater than those seen in the temperate watersheds. Jorge Corredor et
al. conclude this group of papers with a look at nutrient limitation and its
response to human activities in tropical marine systems, with a focus on the
Caribbean.
The next three papers all tackle an enduring paradox in ecosystem
ecology: the question of why N limitation remains so widespread despite the
occurrence of organisms that can fix atmospheric nitrogen. Eight years ago
in this journal, Peter Vitousek and Bob Howarth published a widely read and
influential analysis of this issue. Both scientists (along with co-authors) revisit
the question here. Vitousek and Chris Field present a new simulation model of
N fixation in terrestrial systems, one in which costs of fixation, N losses, light
availability, P limitation and grazing are all addressed. They use this model
to explore the potential constraints on fixation in the terrestrial biosphere,
as well as how both N fixation and limitation may respond to elevated CO2.
Howarth et al. also describe a new model of N fixation, this time one designed
for cyanobacteria in estuaries. Their conclusions, namely that a combination
of biotic (especially grazing) and biogeochemical (notably Mo availability)
constraints can interact to keep rates of N fixation low to absent in estuarine
sytems, have striking parallels to the Vitousek and Field paper, and suggest
that more general, unifying models of N fixation may be possible. Finally,
Tim Crews concludes this section with an alternative view on the patterns in
symbiotic N fixation that occur in the terrestrial biosphere. Crews argues that
3
the presence or absence of N-fixing plant symbioses should first be viewed in
an evolutionary context, with a focus on the radiation of the family Fabaceae.
David Hooper and Loretta Johnson conclude the issue with an investiga
tion of the interactions between nitrogen limitation and water availability in
dryland ecosystems. They survey published data on responses to fertilizer
across a broad-scale gradient in annual precipitation, and conclude that there
is not a shift in primary limitation from water to N across this gradient, but
that co-limitation better explains the data.
The Termas de Chillan workshop was sponsored by the Mellon Founda
tion and the Inter-American Institute for Global Change (IAI). The Mellon
Foundation also supports the SCOPE Nitrogen Project. Bob Howarth and I
served as co-chairs for the meeting; other members of the steering committee
included Peter Vitousek, Doris Soto, Juan Armesto and Osvaldo Sala. Juan
Armesto was the local host and suggested the wonderful location in which the
workshop was held. The boundless energy and enthusiasm shown by partici
pants both during and after the meeting were instrumental to the success of
this volume; my sincere thanks to all of you.
Alan R. Townsend, Editor
University of Colorado, U.S.A.
4
International Scope Project on Nitrogen Transport and
Transformations: A Regional and Global Analysis
Objectives and Activities
• to foster the necessary synergism between scientist of many disciplines
(marine ecologists, forest ecologists, agricultural scientists, microbiol
ogists, atmospheric chemists, oceanographers, hydrologists) in order to
help develop new approaches for the study of nitrogen cycling;
• to refine the global nitrogen budget and develop regional budgets for
selected key and contrasting regions of the world;
• to more fully understand the problems stemming from accelerated
nitrogen cycling, and the inter-relationships among these problems.
Scientific Advisory Committee
Co-chairs:
Robert Howarth (USA)
John Freney (Australia)
Members:
Frank Berendse (The Nctherlands)
Pornpimol Chaiwanakupt (Thailand)
Valery Kudeyarov (Russia)
Scott Nixon (USA)
Peter Vitousek (USA)
Zhu Zhao-liang (People's Republic of China)
Consultants:
Ragner Elmgren (Sweden)
James Galloway (USA)
Alan Townsend (USA)
G~!:,~
COMMITTEE
ON PROBLEMS
OF THE ENVIRONMENT
Biogeochemistry 46: 5-6, 1999.
© 1999 Kluwer Academic Publishers.
N An etymology of nitrogen and
l T PO]) -
other related words
JORGE E. CORREDOR
University of Puerto Rico, Department of Marine Sciences, Mayaguez, PR 00680, Puerto
Rico
Received 10 December 1998
Nitrogen, ammonium, diazo salts and diazotroph are words in common use
by scientists, yet few of those concerned with nitrogen research are aware of
their etymology. This note is intended to address the issue.
Perhaps the most ancient word related to nitrogen is "nitre," the name
for its sodium salt known in modern times as sodium nitrate and in earlier
days as salt peter. Most dictionaries trace this word from the Greek "VLTPOV"
through the latinized form "nitrum". Some, however, would ascribe a more
ancient origin to the root arising from the Egyptian and rendered as "ntry".
The word "ammonium" has a similarly remote etymological origin.
During the final centuries of the Roman empire, Greco-Roman influence
had extended throughout the Mediterranean region, reaching as far as Egypt
and Libya. This influence was so pervasive that the major Greco-Roman and
Egyptian gods were, in some cases, fused into one deity, as was the case for
Jupiter-Ammon, the king of Greco-Roman gods; and, as Amen Ra, king of
gods and god of the sun for the Egyptians. At this time, there existed a temple
dedicated to the god in Lybia where "ammoniacal" salts were first extracted.
Although there are different versions as to the precise extraction process, both
have to do with camels. Mendeleeff (1905) states that the salts were extracted
from the soot accumulated from the burning of camel dung, while Webster's
Dictionary of Word Origins (1991) holds that camel urine from a cesspool
near the temple was heated with soot and seasalt to form sal ammoniac; the
"salt of Ammon". Today, we use the root not only to designate the salts, but
also in words which relate to compounds containing the parent gas ammonia
and its organic derivatives, the amino compounds.
Until the eighteenth century, air was considered to be a single gas. At
this time, the experiments of Priestly and, more forcibly, those of Lavoisier,
demonstrated that, upon combustion, a fraction of the air was consumed,
but a much larger fraction remained unaffected by combustion (the original
