ma s-06-00263 May 20, 2019 Time: 15:45 # 1
PERSPECTIVE
published: 22 May 2019
doi: 10.3389/ ma s.2019.00263
Edi ed by:
Heliana Teixei a,
Uni e si y o A ei o, Po ugal
Re iewed by:
Te esa Alexand a Ribei o
Rod igues,
Po uguese Ins i u e o he Ocean
and A mosphe e (IPMA), Po ugal
Be e ly Johnson,
Ba es College, Uni ed S a es
*Co espondence:
Na han R. Ge aldi
[email p o ec ed]
Special y sec ion:
This a icle was submi ed o
Ma ine Ecosys em Ecology,
a sec ion o he jou nal
F on ie s in Ma ine Science
Recei ed: 13 June 2018
Accep ed: 02 May 2019
Published: 22 May 2019
Ci a ion:
Ge aldi NR, O ega A, Se ano O,
Mac eadie PI, Lo elock CE,
K ause-Jensen D, Kennedy H,
La e y PS, Pace ML, Kaal J and
Dua e CM (2019) Finge p in ing Blue
Ca bon: Ra ionale and Tools
o De e mine he Sou ce o O ganic
Ca bon in Ma ine Deposi ional
En i onmen s. F on . Ma . Sci. 6:263.
doi: 10.3389/ ma s.2019.00263
Finge p in ing Blue Ca bon:
Ra ionale and Tools o De e mine he
Sou ce o O ganic Ca bon in Ma ine
Deposi ional En i onmen s
Na han R. Ge aldi1*, Alejand a O ega1, Osca Se ano2, Pe e I. Mac eadie3,
Ca he ine E. Lo elock2,4, Do e K ause-Jensen5,6, Hila y Kennedy7, Paul S. La e y2,
Michael L. Pace8, Joe i Kaal9and Ca los M. Dua e1
1Red Sea Resea ch Cen e , King Abdullah Uni e si y o Science and Technology, Thuwal, Saudi A abia, 2School o Science,
Cen e o Ma ine Ecosys ems Resea ch, Edi h Cowan Uni e si y, Joondalup, WA, Aus alia, 3School o Li e
and En i onmen al Sciences, Cen e o In eg a i e Ecology, Facul y o Science, Enginee ing and Buil En i onmen , Deakin
Uni e si y, Bu wood, VIC, Aus alia, 4School o Biological Sciences, The Uni e si y o Queensland, B isbane, QLD, Aus alia,
5Depa men o Bioscience, Aa hus Uni e si y, Silkebo g, Denma k, 6A c ic Resea ch Cen e, Depa men o Bioscience,
Aa hus Uni e si y, Aa hus, Denma k, 7School o Ocean Sciences, Bango Uni e si y, Anglesey, Uni ed Kingdom,
8Depa men o En i onmen al Sciences, Uni e si y o Vi ginia, Cha lo es ille, VA, Uni ed S a es, 9Depa amen o
de Eda oloxía e Química Ag ícola, Facul ade de Bioloxía, Uni e sidade de San iago de Compos ela, San iago
de Compos ela, Spain
Blue ca bon is he o ganic ca bon in oceanic and coas al ecosys ems ha is cap u ed on
cen ennial o millennial imescales. Main aining and inc easing blue ca bon is an in eg al
componen o s a egies o mi iga e global wa ming. Ma ine ege a ed ecosys ems
(especially seag ass meadows, mang o e o es s, and idal ma shes) a e blue ca bon
ho spo s and hei deg ada ion and loss wo ldwide ha e educed o ganic ca bon s ocks
and inc eased CO2emissions. Ca bon ma ke s, and conse a ion and es o a ion
schemes aimed a enhancing blue ca bon seques a ion and a oiding g eenhouse gas
emissions, will be aided by knowing he p o enance and a e o blue ca bon. We
e iew and c i ique cu en me hods and he po en ial o nascen me hods o ack he
p o enance and a e o o ganic ca bon, including: bulk iso opes, compound-speci ic
iso opes, bioma ke s, molecula p ope ies, and en i onmen al DNA (eDNA). We ind
ha mos s udies o da e ha e used bulk iso opes o de e mine p o enance, bu his
app oach o en canno dis inguish he con ibu ion o di e en p ima y p oduce s o
o ganic ca bon in deposi ional ma ine en i onmen s. Based on ou assessmen , we
ecommend applica ion o mul iple complemen a y me hods. In pa icula , he use o
ca bon and ni ogen iso opes o lipids along wi h eDNA ha e a g ea po en ial o iden i y
he sou ce and quan i y he con ibu ion o di e en p ima y p oduce s o sedimen a y
o ganic ca bon in ma ine ecosys ems. Despi e he p omising po en ial o hese new
echniques, u he esea ch is needed o alida e hem. This c i ical o e iew can in o m
u u e esea ch o help unde pin me hodologies o he implemen a ion o blue ca bon
ocused clima e change mi iga ion schemes.
Keywo ds: blue ca bon, ca bon accoun ing, en i onmen al DNA, iso opes, o ganic ca bon, seques a ion
F on ie s in Ma ine Science | www. on ie sin.o g 1May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 2
Ge aldi e al. Finge p in ing Blue Ca bon
INTRODUCTION
Blue ca bon ecosys ems (i.e., idal ma shes, mang o e and
seag ass meadows) cons i u e ho spo s o ca bon cycling and a e
among he la ges ca bon sinks in he biosphe e (Nellemann
e al., 2009;Dua e e al., 2013). Among he mul iple ecosys em
se ices ha coas al ege a ed ecosys ems p o ide, he po en ial
o seques e and e ain la ge ca bon s ocks o e millennial
imescales has gene a ed in e es among scien is s and policy
make s (Nellemann e al., 2009;Fou qu ean e al., 2012;Dua e
e al., 2013). Blue ca bon s a egies desc ibe a ange o ac i i ies
o p e en ing o mi iga ing ca bon dioxide (CO2) emissions
h ough he conse a ion and es o a ion o coas al ege a ed
ecosys ems (Wylie e al., 2016), which ank among he mos
h ea ened ecosys ems on Ea h (Dua e e al., 2013).
The accumula ion o ca bon s ocks is he esul o highe
acc e ion a es han decomposi ion and e osion a es o
C-con aining ma e ials (de i us and sedimen ). The e a e se e al
easons why blue ca bon ecosys ems accumula e o ganic ma e
and a e ho spo s o ca bon seques a ion. Fi s , hey a e highly
p oduc i e ecosys ems con e ing CO2in o plan biomass.
Second, abo e-g ound mac ophy e biomass enhances deposi ion
h ough al e ing wa e low, and he below-g ound biomass
educes e osion and adds o ganic ma e o anoxic soils. These
cha ac e is ics esul in he ne accumula ion o bo h li ing
and dead o ganic ma e ial p oduced wi hin he ecosys em
(au och honous), and/o om ex e nal sou ces (alloch honous)
(Kennedy e al., 2010;Sain ilan e al., 2013). Thi d, soils wi hin
blue ca bon ecosys ems ha e low oxygen concen a ions which
educe decomposi ion, he eby con ibu ing o he accumula ion
and p ese a ion o o ganic ca bon (Co g) in he ma ine
en i onmen (Nellemann e al., 2009;Mcleod e al., 2011;
Dua e e al., 2013). Al hough soil and sedimen can ha e
dis inc de ini ions, we use hem in e changeably o acili a e
comp ehension among di e en disciplines.
The alue o blue ca bon ecosys ems in seques e ing Co g
has in ensi ied conse a ion in e es s as a measu e o mi iga e
clima e change and o se CO2emissions. Howe e , while bo h
au och honous and alloch honous sou ces con ibu e o he
soil Co g pool in blue ca bon ecosys ems (Kennedy e al.,
2010), he p esence o alloch honous Co g complica es ca bon
accoun ing exe cises, because o he isk o duplica ing ca bon
seques a ion gains ha may ha e al eady been accoun ed o
whe e alloch honous ca bon om e es ial en i onmen s is
conce ned. In con as , ca bon de i ed om seaweed (K ause-
Jensen and Dua e, 2016;K ause-Jensen e al., 2018), epiphy es o
plank on, also included in he alloch honous in en o y (Kennedy
e al., 2010), a e no accoun ed elsewhe e and could be included
in epo s o ca bon in en o ies om blue ca bon habi a s.
Knowing he o igin o Co g (o en e med “p o enance” wi hin
ca bon accoun ing se ings) in ma ine deposi ional en i onmen s
is impo an o deciphe biogeochemical cycles and unde pin
managemen as i indica es: (1) he key p oduce s o o ganic
ma e accumula ed wi hin blue ca bon ecosys ems and o he
ma ine deposi ional en i onmen s; (2) he deg ee o connec i i y
wi hin and among ma ine and e es ial ecosys ems; (3) he
ul ima e a e o he la ge Co g lux expo ed om ege a ed coas al
habi a s; and (4) he po en ial shi s in ecosys em unc ioning
unde global change h ea s.
Knowledge o ca bon sou ces and luxes among e es ial
and ma ine ecosys ems is use ul o manage s and policy-
make s. This includes he de e mina ion o whe he local si e
managemen is sui able o enhance o main ain blue ca bon
ecosys ems, o whe he ac i i ies ha a e o -si e, o example
hose occu ing in adjoining wa e sheds o habi a s, a e needed
o achie e ecosys em managemen goals. Fo ins ance, epiphy ic
mac oalgae a e o en abundan in seag ass meadows and
associa ed wi h mang o e a eal oo s, ye he con ibu ion o
algae o soil Co g s ocks, ood webs o i s expo o adjacen
habi a s is deba ed (Howa d e al., 2017). Addi ionally, ca bon
om mac oalgae (K ause-Jensen and Dua e, 2016) and seag ass
(Dua e and K ause-Jensen, 2017) g owing in coas al habi a s can
be ound in deep ocean en i onmen s, and he e is he possibili y
ha ca bon om mang o es and idal ma shes is also expo ed
o he deep ocean.
Thus, he e is a need o elucida e bo h he sou ces o
Co g in blue ca bon soils as well as he con ibu ion o hese
habi a s and o he p ima y p oduce s o ca bon seques a ion
in deposi ional en i onmen s (K ause-Jensen and Dua e, 2016;
Dua e and K ause-Jensen, 2017). Unde s anding connec i i y,
in e ms o ca bon lows ac oss ma ine ecosys ems, is key
o suppo blue ca bon accoun ing as well as he success ul
managemen o aqua ic ecosys ems wi hin land- and seascapes
(Smale e al., 2018).
The pu pose o his pape is o syn hesize exis ing in o ma ion
on Co g p o enance in ma ine sys ems and he me hods used,
and hen de e mine wha echniques could be used o imp o e
ou unde s anding o blue ca bon sou ces. Al hough we ocus on
well-s udied ege a ed habi a s, deposi ional en i onmen s in he
open ocean can also p o ide an impo an global sink o blue
ca bon, including ca bon om plank onic sou ces and ca bon
expo ed om blue ca bon ecosys ems eaching he deep sea
(Dua e and K ause-Jensen, 2017). Expo o ca bon om he
su ace ocean o oceanic sinks is enhanced by oceanic on s
(S ukel e al., 2017), and ma ine canyons also concen a e ca bon
luxes om coas al ege a ed sys ems o oceanic sinks (K ause-
Jensen and Dua e, 2016). Embedding deep ocean sinks in o
blue ca bon amewo ks is cu en ly hinde ed by, among o he
hings, di icul y in iden i ying he sou ces o ca bon o hose
sinks (K ause-Jensen e al., 2018). The me hods we discuss a e
also applicable o ace he Co g p o enance in he deep ocean and
possibly o ack oceanic on s (Kha e and Cha u edi, 2012).
O e iew o Blue Ca bon P o enance
Bulk p ope ies o soils such as C and N elemen al (%) and
s able iso opic (δ13C and δ15N) composi ion ha e been widely
es ed and used o quan i ying sou ces o o ganic ma e
in mang o e, idal ma sh and seag ass soils (Kennedy e al.,
2010;G eine e al., 2016). These ace s ha e been used o
di e en ia e be ween e es ial and ma ine sou ces o o ganic
ma e (F y and She , 1989), among ma ine sou ces wi h dis inc
iso opic a ios such as seag asses, ses on, and mac oalgae (e.g.,
Kennedy e al., 2010;G eine e al., 2016) and be ween C3
and C4 ege a ion (Smi h and Eps ein, 1970). Appo ioning
F on ie s in Ma ine Science | www. on ie sin.o g 2May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 3
Ge aldi e al. Finge p in ing Blue Ca bon
o o ganic ma e sou ces using C and N concen a ion and
iso opes depends on: (1) accu a e knowledge o po en ial sou ce
alues; (2) sou ces wi h signi ican ly di e en alues; and (3)
he assump ion o li le o no al e a ion o sou ce alues du ing
decomposi ion (Fou qu ean and Sch lau, 2003;Bouillon e al.,
2008). Ye , sou ces o o ganic ma e in coas al ecosys ems can
be complex wi h a iable and o e lapping iso opic alues among
plan species, issues, mic ohabi a s, seasons and g ow h cycle,
which complica es he use o bulk C and N iso opic a ios o
disce n Co g sou ces (Ma chand e al., 2003;Blai and Alle ,
2012). Fo example, i is di icul o dis inguish he con ibu ion
o mang o e, idal ma sh and o he e es ial plan s o soil Co g
using δ13C because hese sou ces ha e simila iso opic alues
(Sain ilan e al., 2013). Thus, he e is a need o me hods o
complemen he in o ma ion p o ided by C and N iso opic
alues (Cloe n e al., 2002). Recen s udies ha e highligh ed ha
mo e speci ic ma ke s, such as eDNA and compound-speci ic
iso opes, could help educe unce ain y when de e mining he
sou ces o Co g (Ree e al., 2017). The e o e, he analyses o
addi ional p oxies ha a e e iewed he e, ha e he po en ial o
g ea ly enhance ou unde s anding o he luxes o Co g in ma ine
sys ems (see Table 1 o summa y).
Recen De elopmen s in T acing Ca bon
P o enance
Bulk Hyd ogen, Oxygen and Sul u Iso opes
In addi ion o δ13C and δ15N iso opic a ios, s udies acing he
o igin o o ganic ma e in ma ine and eshwa e ecosys ems
ha e measu ed δ18O, δ2H, and δ34S (Pe e son and F y, 1987).
The eme ging use o δ2H in ma ine soils has po en ial o
p o ide e idence o he sou ce o o ganic ma e . δ2H alues
ha e been used o measu e esou ce use by aqua ic consume s
demons a ing he u ili y o his me hod o po en ially be
used o ack Co g p o enance. Fo example, a combina ion
o δ2H and C and N iso opes was used o de e mine clams’
consump ion o o ganic ma e de i ed om mac oalgae and
mic oalgae (Hondula and Pace, 2014). Disc imina ing he die o
clams was possible because mic oalgae, mac oalgae, seag ass and
we land mac ophy es di e in δ2H (Hondula and Pace, 2014).
In addi ion, Dua e e al. (2018) ecen ly showed ha Red Sea
seag ass and mac oalgae ha e dis inc δ2H signa u es and ha
he combina ion o δ2H and δ13C holds p omise o disc imina e
hese ca bon sou ces in Co g sedimen s ocks. Se e al ac o s
such as pho osyn hesis, lipid con en , iso opic disc imina ion
du ing wa e up ake, biochemical and biophysical p ocesses, and
en i onmen al seasonali y allow di e en ia ion o δ2H alues in
p ima y p oduce s (Hondula e al., 2014;Ladd and Sachs, 2015;
Adame e al., 2016).
A combina ion o δ18O wi h δ2H could be used o
de e mine he p o enance o Co g in sedimen and al hough
using his combina ion has no been used o his o ou
knowledge, he ollowing examples demons a e i s ele ance
o acking Co g p o enance. While δ18O is no al e ed upon
wa e up ake by plan s (Roden e al., 2000), i is ac iona ed
du ing pho osyn hesis leading o a ia ion o δ18O alues o
plan biomass (Ba bou e al., 2007). Va ia ion o δ18O in
mang o e woody biomass has been linked o a ia ion in ain all
(Ve heyden e al., 2004) and salini y (Ish-Shalom-Go don e al.,
1992). Ye , di ec wa e shed compa ison o δ18O o biomass om
co-occu ing e es ial and aqua ic species a e needed o alida e
his echnique. Mo eo e , he iso opic alues o δ2H and δ18O o
wa e in mang o e s em wa e a e dis inc om hose o adjacen
e es ial plan s (Wei e al., 2013) and a y wi h ain all and
among species (San ini e al., 2015;Lo elock e al., 2017), bu
di ec compa ison o iso opic alues in wa e wi h biomass om
he same plan s ha e no ye been made.
The e a e complexi ies in using δ18O and δ2H a ios o iden i y
unique ca bon sou ces. Fi s , iso opic composi ion o p ima y
p oduce s is no uni e sal and second, he sou ce ma e ials a e
equi ed o de e mine p o enance on a case-by-case basis. Some
complica ions such as he p esence o ino ganic hyd ogen and
he exchange o hyd ogen a e soil collec ion, may be o e come
wi h he use o s ingen ex ac ion and d ying me hods (Chesson
e al., 2009;Meie -Augens ein e al., 2013;Ruppen hal e al., 2013;
So o e al., 2017). Howe e , o he complica ions emain o be
sol ed including measu ing only a small ac ion o o al o ganic
ma e due o incomple e ex ac ion (<80% o he o al o ganic
ma e ; Ruppen hal e al., 2013), accoun ing o sou ce speci ic
elemen a ios (i.e., C/H and C/O), isola ing non-exchangeable
H, and de e mining he e ec o bac e ial deg ada ion on δ2H
and δ18O. While hese iso opic ace s a e success ully used o
s udy animal mo emen (Rubens ein and Hobson, 2004) and
could assess ood web in e ac ions (Zanden e al., 2016), he e is
li le o no in o ma ion on how bulk alues may change du ing
decomposi ion. In summa y, δ2H along wi h δ18O may be used o
de e mine con ibu ion o di e en p ima y p oduce s o o ganic
ma e in soils o possibly e en o ganic ma e de i ed om
mang o e ees in di e en en i onmen s. Howe e , hei use o
disc imina e sou ces o Co g in blue ca bon sedimen s has no
ye been a emp ed and he complica ions men ioned should be
add essed o de e mine he accu acy o hese me hods.
Measu ing sul u iso opes also has he po en ial o
disc imina e sou ces o Co g in ma ine deposi ional
en i onmen s. Exposu e o plan oo s o sul ide in ma ine
soils a ec s hei sul u iso opic alues due o inco po a ion o
34S-deple ed sul ides (leading o lowe δ34S alues), which does
no occu in non- oo ed p ima y p oduce s such as mac oalgae
(Pe e son and F y, 1987). When used in combina ion wi h
o he ace s, sul u s able iso opes imp o e he elucida ion o
sou ces o o ganic ma e . Fo ins ance, Monc ei and Sulli an
(2001) used δ34S, in combina ion wi h δ13C and δ15N, o esol e
he con ibu ion o seag ass and epiphy ic algae o he die o
ma ine consume s. Connolly e al. (2004) e iewed es ua ine
and ma ine ood web s udies o conclude ha he use o δ34S
iso opes, in combina ion wi h δ13C, yields a high p obabili y o
dis inguishing he con ibu ion o di e en p oduce s o aqua ic
ood webs. Howe e , whe eas δ34S has been used ex ensi ely o
esol e ood sou ces in ood web s udies, he use o his iso ope
a io o disc imina e sou ces o Co g in ma ine soils is mo e
complica ed. Soils con aining sul ide mine al a e common when
anoxic condi ions pe ain in he sedimen and hese mine als
a e abou 40% deple ed in 34S compa ed o seawa e sul a e.
Iso opic analysis o δ34S uses oughly he same echnology as
F on ie s in Ma ine Science | www. on ie sin.o g 3May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 4
Ge aldi e al. Finge p in ing Blue Ca bon
TABLE 1 | Summa y o he ad an ages, and po en ial limi a ions o echniques o disce n he low o o ganic ca bon in ma ine ecosys ems.
Me hod Ad an ages Disad an ages Disce n sou ce
iden i y
Disce n sou ce
con ibu ion
Cos pe
sample ($US)
Bulk C and N iso opes Weal h o in o ma ion on
sou ces and limi a ions
Limi a ions in disce ning
mul iple sou ces
medium medium ∼10
Bulk H and O iso opes Disce n con ibu ion o
e es ial and mang o e
ca bon sou ces and possibly
di e en plan issues
Changes in hyd ogen iso ope
a e collec ion and p esence
o ino ganic hyd ogen
unknown unknown ∼25
Bulk Sul u iso opes Showed u ili y in ood web
s udies
No enough known abou
ans o ma ion in soils
unknown unknown ∼20
Bioma ke s (e.g., lipids) Good o disce ning be ween
e es ial and ma ine o ganic
ma e
Can be di icul o appo ion
o speci ic sou ces
medium medium ∼50–300
Compound-speci ic iso opes
(e.g., lipid iso opes and
amino acid iso opes)
La ge speci ici y and s abili y
han bulk o g. ma e
No enough known abou
ans o ma ion in soils
medium high ∼200
eDNA Iden i y sou ce o species B ead h and accu acy o
mac ophy e p ime s need o
be es ed
high medium∗∼30
∗Expe imen s s ill need o be conduc ed o es bo h he a ia ion in DNA deg ada ion among species and compa ed o o he o ganic ca bon componen s.
o δ13C and δ15N, bu i is ecommended ha non-acidi ied
samples a e un o main ain he in eg i y o he soil δ34S o
sul u iso ope analysis (Connolly and Schlache , 2013), and i
bulk soil is analyzed he esul an δ34S alues is a measu e o
bo h ino ganic and o ganic sul u iso opic composi ion which
can be much mo e iso opically deple ed han any o he po en ial
Co g sou ces (O eska e al., 2018). Al hough his ep esen s an
un apped esea ch oppo uni y, a i s s ep would be o employ
me hodology ha sepa a es ino ganic om o ganic sul u in he
soils p io o analysis. In addi ion, i emains o be in es iga ed
how he inco po a ion o educed sul u in o o ganic ma e
a ec s he δ34S o Co g du ing diagenesis.
Molecula P ope ies o Bulk O ganic Ma e
The e a e mul iple me hods o cha ac e ize he chemical
composi ion o o ganic ca bon in soils (De ien e al., 2017).
The mos common sou ces o o ganic ma e in blue ca bon
ecosys ems ( ascula plan s, mac oalgae, phy oplank on, ungi,
bac e ia, zooplank on, e c.) can ha e di e en biopolyme
chemical composi ion (e.g., polysaccha ides, p o eins, lignin,
chi in, pep idoglycan). Di e ences in biopolyme iden i y and
abundance can be analyzed wi h in a ed spec oscopy (IR) o
cha ac e ize ma ine Co g (Benne e al., 1992;T e a han-Tacke
e al., 2017). IR is a apid, non-des uc i e and cos -e icien
me hod and is he e o e a e y use ul ool o bulk chemical
cha ac e iza ion o blue ca bon. Howe e , a disad an age o using
IR is ha some sou ces can ha e simila biopolyme inge p in s.
Ano he complemen a y me hod o cha ac e ize he composi ion
o Co g is nuclea magne ic esonance spec oscopy (solid-
s a e 13C NMR). B oad mo phological, physical and chemical
cha ac e is ics o o ganic ma e ac ions can be de e mined
wi h 13C NMR, including dissol ed and pa icula e Co g, and
ecalci an o ganic ma e . Al hough 13C NMR has been used o
desc ibe Co g in e es ial soils (Baldock e al., 2004), he use in
ma ine sys ems maybe mo e complex because he ma ine Co g
o en unde goes g ea e le els o p ocessing be o e deposi ion
compa ed o Co g in e es ial sys ems (Baldock e al., 2004;
Hayes e al., 2017;Kelleway e al., 2017;Mac eadie e al., 2017).
An a ea o u u e esea ch is o de elop molecula mixing
models wi h he applica ion o chemome ic app oaches (Douce
e al., 2008) based on bo h IR and NMR esul s o cha ac e ize
blue ca bon sou ces.
Gas ch oma og aphy coupled wi h mass spec ome y (GC-
MS) can also be applied o blue ca bon inge p in ing.
Simila ly, py olysis has been used o disce n alloch honous and
au och honous o ganic ma e in mang o e soils (Ma chand
e al., 2008). GC-MS can iden i y he he mal o chemical
deg ada ion o mac omolecules. Fo example, lignin composi ion
di e s be ween angiospe ms s. gymnospe ms and be ween
woody issues s. non-woody issues (Haddad and Ma ens,
1987). Thus, lignin can be analyzed by GC-MS a e cup ic oxide
oxida ion, which can p o ide in o ma ion on he abundance
and sou ce o plan ma e ial. Lignin can also be analyzed
by he mal deg ada ion using analy ical py olysis which can
hen be analyzed wi h GC-MS (Py-GC-MS; Ca e al.,
2010;Zhang e al., 2016). Due o he in asi e na u e o
py oly ic b eakdown, Py-GC-MS is quan i a i ely weak bu
has he ad an age ha i also p o ides in o ma ion on o he
mac omolecula ma e ials, such as polysaccha ides, p o eins,
chi in (in zooplank on and ungi), pep idoglycan (in bac e ia),
chlo ophyll (in phy oplank on), cha ed o ganic ma e (an
impo an ype o ecalci an o ganic ma e ) and o he s (e.g.,
cu in, sube in, algaenan, and annin; Ca e al., 2010 and
e e ences he ein). Such in o ma ion can be use ul no only
as a molecula sc eening me hod o iden i y sou ces, bu can
also be used o complimen o alida e less complex da a om
IR, elemen al o iso opic analysis. Analysis o he molecula
p ope ies o bulk o ganic ma e does necessi a e speci ic and
ad anced analy ical me hodologies such as IR, NMR, GC-
MS, and PY-GC-MS.
F on ie s in Ma ine Science | www. on ie sin.o g 4May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 5
Ge aldi e al. Finge p in ing Blue Ca bon
Bioma ke s (Ta ge ed Compounds)
Bioma ke s, such as n-alkanes and phenolic compounds, ha e
been p oposed as axonomic inge p in s and he bioma ke
p o ile o some ma ine p ima y p oduce s has been cha ac e ized
(Zido n, 2016;Gache e al., 2017). Lipids can p o ide con enien
bioma ke s o ace he sou ce and a e o Co g and ha e
g ea po en ial as a molecula bioma ke o coas al sys ems
(De ien e al., 2017). Fo example, n-alkanes lipids oge he
wi h s able C and N iso opic composi ions, ha e been used
o quan i y he sou ce o Co g along es ua ine g adien s (Ja é
e al., 2001;He e al., 2014). In addi ion, n-alkanes can indica e
he ela i e p opo ion o e es ial and ma ine sou ces o
o ganic ma e (Silliman e al., 1996;O iz e al., 2013) and
can di e en ia e he sou ce o o ganic ma e wi hin coas al
sys ems among e es ial sou ces, eme gen aqua ic plan s, and
subme ged mac ophy es (Sikes e al., 2009). O he compounds
wi h he po en ial o inge p in ing Co g include p o eins, such
as glomalin which has been used o indica e e es ial-de i ed
ca bon in blue ca bon soils (Adame e al., 2012;López-Me ino
e al., 2015;Wang e al., 2018). In gene al, biogeochemical
plas ici y o bioma ke s can exis wi hin species based on hei
geog aphical dis ibu ion and h ough ime (De ien e al.,
2017). Simila o molecula p ope ies o bulk o ganic ma e ,
bioma ke analysis equi es ad anced analy ical me hodologies,
o example liquid ch oma og aphy (LC, HPLC), GC and MS.
Biogeochemical plas ici y o bioma ke s can exis wi hin species
based on hei geog aphical dis ibu ion and h ough ime
(De ien e al., 2017). A ecen e iew p o ides a good o e iew
o using bioma ke s o ace o ganic ma e (De ien e al.,
2017). To da e, ew s udies ha e used his app oach o inge p in
sou ces o Co g in blue ca bon soils, and some s udies ha e used
bioma ke s in combina ion wi h compound-speci ic iso opes
(Apos olopoulou e al., 2015).
Compound-Speci ic Iso opes (Amino Acids,
Ca bohyd a es, Lipids)
Compound-speci ic s able iso opes o o ganic ma e can enable
he molecula speci ici y and iso opic alue o compounds o be
exploi ed concomi an ly o ace he o igin and a e o o ganic
ma e (E e shed e al., 2007;Chika aishi, 2014). Many ypes o
amino acids, ca bohyd a es, and lipids ha e been used o iso opic
inge p in ing and o ace Co g sou ces h ough ood webs (De
T och e al., 2012;La sen e al., 2013), wi h he inding ha hey
seem o be conside ably mo e s able and speci ic han ha o
he bulk o ganic ma e (La sen e al., 2015). The δ13C and δ2H
alues o s e ols in li ing algae a e consis en wi h hose ound
in ma ine sedimen s, sugges ing ha he iso opic composi ions
o algal s e ols a e well-p ese ed in sedimen s and he e o e
could be used as ace s o Co g o igin (Chika aishi, 2006). Las ly,
iso opes o amino acids, ha e also been iden i ied as a powe ul
ace o ma e ial o igin, because en i onmen al condi ions ha e
a minimal e ec on δ13C pa e ns o di e en amino acids
in seag ass (Posidonia oceanica) and gian kelp (Mac ocys is
py i e a) (La sen e al., 2013). Thus, pa e ns o δ13C among
indi idual amino acids ha e a much g ea e po en ial han bulk
δ13C o dis inguish be ween Co g de i ed om algae, seag ass,
e es ial plan s, bac e ia and ungi (La sen e al., 2013). O e
ime, sedimen a y diagenesis may lead o inc eased con ibu ion
o bac e ial sou ces (La sen e al., 2015), bu he me hod s ill
seems a p omising complemen a y app oach o o e come some
o he limi a ions o bulk iso ope analysis in es ua ies and o he
complex en i onmen s wi h mixed aqua ic and e es ial inpu s
o de e mining he o igin o o ganic ma e . A ew s udies ha e
used bo h bulk and compound-speci ic iso opes o ack changes
in he p o enance o blue ca bon including s able iso opes wi hin
highe plan lea wax lipids (Johnson e al., 2007) o n-alkanes
(Tanne e al., 2010).
En i onmen al DNA
Finge p in ing ma ine o ganisms h ough en i onmen al
DNA (eDNA) has ecen ly become a widely used echnique
o de e mine he p esence and abundance o indi idual
mac oo ganisms (Rees e al., 2014;Thomsen and Wille sle ,
2015). Mos o he ma ine esea ch using eDNA has a ge ed
mac o auna, while minimal a en ion has been gi en o
mac o lo a (Thomsen and Wille sle , 2015;Goldbe g e al.,
2016), wi h only one pape o ou knowledge on eDNA o
mac ophy es in ma ine sedimen s (Ree e al., 2017). Gi en
ha app oxima ely 3% o cellula Co g is DNA (Landenma k
e al., 2015) and ha eDNA can iden i y indi idual species,
his app oach has g ea po en ial o de e mining he
p o enance o Co g in soils o blue ca bon ecosys ems. In
aqua ic en i onmen s, phy oplank on iden i ied om eDNA
isola ed om sedimen s in deep wa e we e ep esen a i e
o he pelagic communi y (Co inaldesi e al., 2011;Capo
e al., 2015). Howe e , eDNA analysis may unde ep esen
phy oplank on ha lack ha d s uc u es (Boe e e al., 2011b), and
unde ep esen phy oplank on compa ed o e es ial plan s
(Boe e e al., 2011a), due o di e en ial p ese a ion o hei
DNA. Cu en ly, he sole s udy using eDNA o measu e he
p o enance o blue ca bon ound ha seag ass meadows had
a g ea e inpu o au och honous Co g based on eDNA han
when sou ces o Co g whe e es ima ed using δ13C and δ15N
(Ree e al., 2017). This disc epancy be ween me hods highligh s
he need o expe imen ally es he ela ionship be ween bulk
o ganic ca bon sou ces and sequenced eDNA du ing diagenesis
a di e en imescales.
The basic s eps in analyzing eDNA using me aba coding
include isola ing DNA om sedimen , eplica ing a ge
DNA sequences h ough polyme ase chain eac ion (PCR),
de e mining he base pai s o he eplica ed sequences using nex
gene a ion sequencing, and ma ching he sequences o known
axa. The ela ionship be ween eDNA and na u al abundance is
be e when ocusing on single axon o species using quan i a i e
PCR o ela ed echniques (Ya es e al., 2019), as compa ed o
using PCR and me aba coding which may no ha e a ela ionship
be ween ini ial DNA concen a ion and inal sequences bu ha e
he bene i o uniquely iden i ying many species in a single
sample. To ela e he numbe o DNA sequences o he
abundance o o ganisms based on me aba coding, knowledge
o he ac o s ha a ec eDNA quan i y in sedimen and PCR
bias (i.e., he p e e en ial eplica ion o some DNA sequences
ela i e o o he s) should be iden i ied and measu ed (Yoccoz
e al., 2012). When using eDNA eads as an indica o o blue
F on ie s in Ma ine Science | www. on ie sin.o g 5May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 6
Ge aldi e al. Finge p in ing Blue Ca bon
ca bon p o enance, he ac o s ha may al e he ela ionship
be ween DNA and Co g should also be unde s ood. Po en ial
a i ac s ha dese e a en ion when using eDNA o ack
blue ca bon include: (1) DNA may deg ade a a as e a e
han o he Co g componen s, such as ca bohyd a es and o he
mac omolecules (Volkman, 2006), so he e is he po en ial
o eDNA o unde es ima e alloch honous Co g and species
wi h ela i ely less esis an cellula s uc u e (e.g., algae s.
ascula plan s); (2) p ime s need o be es ed o ensu e ha he
species hough o con ibu e o he Co g in soil a e ampli ied
because p ime ampli ica ion is impe ec (Deagle e al., 2014);
(3) he ini ial and ampli ied numbe o sequences may no be
ela ed when using PCR (Acinas e al., 2005); and (4) accu a e
inge p in ing equi es ha sequences o he pu a i e sou ce
p ima y p oduce s be deposi ed in e e ence da a banks, which
is no always he case. Recen s udies ha e used mock samples
o assess whe he PCR amplicons a e ela ed o ini ial DNA
concen a ion, inding ha his ela ionship does exis o mos
species (Thomsen e al., 2016). Gi en ha eDNA wi hin aqua ic
sedimen s ha e been used o ack changes o e millennia in
he su ounding e es ial and aqua ic au o oph communi ies
(Capo e al., 2015;Sjög en e al., 2016) and Co g con ibu ions
(Coolen e al., 2007;Boe e e al., 2011a), he e is g ea po en ial
o using eDNA o ack he p o enance and a e o Co g
wi hin blue ca bon ecosys ems (Ree e al., 2017). The po en ial
esolu ion o eDNA o de ail ca bon con ibu ion o species le el,
makes his app oach unpa alleled by any o he app oach used
o inge p in he sou ces o Co g in blue ca bon soils. Howe e ,
he limi a ions men ioned when using PCR should be add essed
be o e in e ing a ela ionship be ween me aba coding esul s
and con ibu ion o Co g.
Common Me hodological Issues
The dispa a e echniques desc ibed he e sha e limi a ions ha
can likely be add essed o imp o e ou abili y o de e mine
he p o enance o seques e ed Co g in he ma ine en i onmen
(Table 1). Fi s , all he echniques assume conse ed ela ionships
be ween he sou ce o speci ic ma ke s and hose in sedimen a y
Co g pools, ye changes in he ma ke s h ough space and
ime may occu , hence hese changes need o be quan i ied.
Thus, some o hese me hods should be conside ed quali a i e
o semi-quan i a i e un il his assump ion has been es ed.
Second, all me hods a e based on known s anda ds, such as
a comp ehensi e lib a y o known DNA sequences, iso opic
alues o sou ce ma e ials o bioma ke p o iles, and i equi es
a communi y e o o de elop and expand hese s anda ds so
as o enable he ull powe o hese echniques. Thi d, hese
me hods o en depend on la ge da abases and/o necessi a e
compu a ionally in ensi e p og ams o ma ch samples wi h
s anda ds. Fo example, mixing models a e o en used o s able
iso opes bu ha e mul iple limi a ions (F y, 2013), and ad ances
ha e been made such as Bayesian me hods ha can include
addi ional in o ma ion o educe unce ain y in unde e mined
sys ems (Moo e and Semmens, 2008). Mixing models o iso ope
a ios o speci ic compounds a e less de eloped han o bulk
iso ope a ios and need u he e inemen o alida e hei use.
Finally, me hods a e cons an ly being de eloped and specialized
o de e mine Co g p ope ies and many a e associa ed wi h
specialized equipmen ha can be eso e ic and oo expensi e o
many esea che s (see Table 1 o es ima ed cos ). Howe e , as
is he case wi h DNA sequencing, many me hods ha e and will
become a ailable o a b oade scien i ic communi y as echnology
imp o es and cos s con inue o dec ease, a consequence o he
inc easingly la ge numbe o esea che s using hese echniques.
CONCLUSION
We e iewed and c i iqued mul iple me hods ha ha e he
po en ial o imp o e ou unde s anding o he p o enance and
a e o Co g wi hin and among coas al ecosys ems. Ou goal is
o encou age esea ch aimed a imp o ing he assessmen o
he Co g o igin in blue ca bon ecosys ems which is needed o
deciphe biogeochemical cycles and unde pin managemen such
as blue ca bon ini ia i es. This ad ance would include assessmen
o species o mac oalgae, mic ophy oben hos and epi auna,
which can ha e high p oduc ion a es, bu hei con ibu ion o
blue ca bon has been illusi e because o cu en limi a ions in
acking hei o igin and a e. In addi ion, ecen esea ch has
sugges ed ha coas al p ima y p oduce s, such as mac oalgae
and seag ass, could signi ican ly con ibu e o Co g seques a ion
beyond hei habi a , including in he deep ocean (K ause-
Jensen and Dua e, 2016;Dua e and K ause-Jensen, 2017), bu
di ec measu es o hei con ibu ion a e limi ed a bes . The
abili y o accu a ely de e mine he iden i y and con ibu ion
o p ima y p oduce s o soil Co g will likely depend on a
combina ion o he p e iously discussed me hods ha minimize
he associa ed limi a ions. In ou opinion, he me hodologies
wi h he g ea es po en ial o de e mine he p o enance o soil
Co g a e he C and N s able iso opes o lipids o de e mine
he quan i y o disce ned axa in combina ion wi h eDNA o
iden i y he species ha con ibu e o he iso opic composi ion.
The abili y o mi iga e he nega i e e ec s o ele a ed a mosphe ic
CO2can be aided by managemen schemes ha main ain
exis ing ca bon s o age and p omo e ca bon seques a ion.
The ma ine en i onmen , and blue ca bon ecosys ems in
pa icula , a e ho spo s o ca bon s o age. Enhanced knowledge
o he sou ces and a e o Co g s o ed in ma ine sedimen s
is impo an o bo h managing coas al ca bon s ocks and
unde s anding ca bon cycling.
AUTHOR CONTRIBUTIONS
NG and CD concei ed he idea o he manusc ip . All au ho s
con ibu ed o he w i ing and e ising o he manusc ip .
FUNDING
This manusc ip was ini ia ed a he Blue Ca bon Wo kshop held
a KAUST on Ma ch 19 h o he 23 d 2017 and was unded
by KAUST. NG and CD we e suppo ed by KAUST h ough
baseline unding and by he Ta ek Ahmed Ju ali Resea ch Chai
in Red Sea Ecology o CD. OS was suppo ed by an ARC
F on ie s in Ma ine Science | www. on ie sin.o g 6May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 7
Ge aldi e al. Finge p in ing Blue Ca bon
DECRA DE170101524. PM and CL acknowledge he suppo o
an Aus alian Resea ch Council Linkage G an – LP160100242.
HK was suppo ed by he Ecosys em Se ices o Po e y
Alle ia ion p og am Coas al Ecosys em Se ices in Eas A ica
(NE/L001535/1). DK-J was suppo ed by he Danish Cen e o he
En i onmen ’s eDNA syne gy p ojec and by he COCOA p ojec
unde he BONUS p og am unded by he EU 7 h amewo k
p og am and he o me Danish Resea ch Council. MP was
suppo ed by he NSF Vi ginia Coas Rese e LTER p ojec
(DEB1237733 and DEB1832221).
REFERENCES
Acinas, S. G., Sa ma-Rupa a m, R., Klepac-Ce aj, V., and Polz, M. F. (2005). PCR-
induced sequence a i ac s and bias: insigh s om compa ison o wo 16s RNA
clone lib a ies cons uc ed om he same sample. Appl. En i on. Mic obiol. 71,
8966–8969. doi: 10.1128/AEM.71.12.8966-8969.2005
Adame, M. F., F y, B., and Bunn, S. E. (2016). Wa e iso ope cha ac e is ics o a
lood: b isbane i e , Aus alia. Hyd ol. P ocess. 30, 2033–2041. doi: 10.1002/
hyp.10761
Adame, M. F., W igh , S. F., G inham, A., Lobb, K., Reymond, C. E., and Lo elock,
C. E. (2012). Te es ial–ma ine connec i i y: pa e ns o e es ial soil ca bon
deposi ion in coas al sedimen s de e mined by analysis o glomalin ela ed soil
p o ein. Limnol. Oceanog . 57, 1492–1502. doi: 10.4319/lo.2012.57.5.1492
Apos olopoulou, M.-V., Mon eyne, E., K ikonis, K., Pa lopoulos, K., Roose, P.,
and Dehai s, F. (2015). n-Alkanes and s able C, N iso opic composi ions
as iden i ie s o o ganic ma e sou ces in Posidonia oceanica meadows o
Alexand oupolis Gul , NE G eece. Ma . Pollu . Bull. 99, 346–355. doi: 10.1016/
j.ma polbul.2015.07.033
Baldock, J. A., Masiello, C. A., Gélinas, Y., and Hedges, J. I. (2004). Cycling and
composi ion o o ganic ma e in e es ial and ma ine ecosys ems. Ma . Chem.
92, 39–64. doi: 10.1016/j.ma chem.2004.06.016
Ba bou , M. M., Fa quha , G. D., Hanson, D. T., Bick o d, C. P., Powe s, H.,
and Mcdowell, N. G. (2007). A new measu emen echnique e eals empo al
a ia ion in δ18O o lea - espi ed CO2. Plan Cell En i on. 30, 456–468. doi:
10.1111/j.1365-3040.2007.01633.x
Benne , R., Pakulski, J. D., Mcca hy, M., Hedges, J. I., and Ha che , P. G. (1992).
Bulk chemical cha ac e is ics o dissol ed o ganic ma e in he ocean. Science
255, 1561–1564. doi: 10.1126/science.255.5051.1561
Blai , N. E., and Alle , R. C. (2012). The a e o e es ial o ganic ca bon in he
ma ine en i onmen . Annu. Re . Ma . Sci. 4, 401–423. doi: 10.1146/annu e -
ma ine-120709-142717
Boe e, A. C., Rijps a, W. I. C., De Lange, G. J., Sinninghe Dams é, J. S., and Coolen,
M. J. L. (2011a). P ese a ion po en ial o ancien plank on DNA in pleis ocene
ma ine sedimen s. Geobiology 9, 377–393. doi: 10.1111/j.1472-4669.2011.
00290.x
Boe e, A. C., Sinninghe Dams é, J. S., Rijps a, W. I. C., Volkman, J. K.,
and Coolen, M. J. L. (2011b). Sou ce-speci ic a iabili y in pos -deposi ional
DNA p ese a ion wi h po en ial implica ions o DNA based paleoecological
eco ds. O g. Geochem. 42, 1216–1225. doi: 10.1016/j.o ggeochem.2011.08.005
Bouillon, S., Bo ges, A. V., Cas añeda-Moya, E., Diele, K., Di ma , T., Duke, N. C.,
e al. (2008). Mang o e p oduc ion and ca bon sinks: a e ision o global budge
es ima es. Glob. Biogeochem. Cycles 22:GB2013. doi: 10.1029/2007GB003052
Capo, E., Deb oas, D., A naud, F., and Domaizon, I. (2015). Is plank onic
di e si y well eco ded in sedimen a y DNA? Towa d he econs uc ion o
pas p o is an di e si y. Mic ob. Ecol. 70, 865–875. doi: 10.1007/s00248-015-
0627-2
Ca , A. S., Boom, A., Chase, B. M., Robe s, D. L., and Robe s, Z. E. (2010).
Molecula inge p in ing o we land o ganic ma e using py olysis-GC/MS: an
example om he sou he n cape coas line o Sou h A ica. J. Paleolimnol. 44,
947–961. doi: 10.1007/s10933-010-9466-9
Chesson, L. A., Podlesak, D. W., Ce ling, T. E., and Ehle inge , J. R. (2009).
E alua ing unce ain y in he calcula ion o non-exchangeable hyd ogen
ac ions wi hin o ganic ma e ials. Rapid Commun. Mass Spec om. 23, 1275–
1280. doi: 10.1002/ cm.4000
Chika aishi, Y. (2006). Ca bon and hyd ogen iso opic composi ion o s e ols
in na u al ma ine b own and ed mac oalgae and associa ed shell ish. O g.
Geochem. 37, 428–436. doi: 10.1016/j.o ggeochem.2005.12.006
Chika aishi, Y. (2014). “T ea ise on geochemis y,” in T ea ise on Geochemis y—
O ganic Geochemis y, 2nd Edn, eds K. Tu ekian and H. Holland (Ams e dam:
Else ie ), 95–123.
Cloe n, J. E., Canuel, E. A., and Ha is, D. (2002). S able ca bon and ni ogen
iso ope composi ion o aqua ic and e es ial plan s o he San F ancisco Bay
es ua ine sys em. Limnol. Oceanog . 47, 713–729. doi: 10.4319/lo.2002.47.3.
0713
Connolly, R. M., Gues , M. A., Mel ille, A. J., and Oakes, J. M. (2004). Sul u
s able iso opes sepa a e p oduce s in ma ine ood-web analysis. Oecologia 138,
161–167. doi: 10.1007/s00442-003-1415-0
Connolly, R. M., and Schlache , T. A. (2013). Sample acidi ica ion signi ican ly
al e s s able iso ope a ios o sul u in aqua ic plan s and animals. Ma . Ecol.
P og. Se . 493, 1–8. doi: 10.3354/meps10560
Coolen, M. J. L., Volkman, J. K., Abbas, B., Muyze , G., Schou en, S., and
Sinninghe Dams é, J. S. (2007). Iden i ica ion o o ganic ma e sou ces in
sul idic la e Holocene An a c ic jo d sedimen s om ossil DNA sequence
analysis. Paleoceanog aphy 22:A2211. doi: 10.1029/2006PA001309
Co inaldesi, C., Ba ucca, M., Luna, G. M., and Dell’anno, A. (2011). P ese a ion,
o igin and gene ic imp in o ex acellula DNA in pe manen ly anoxic
deep-sea sedimen s. Mol. Ecol. 20, 642–654. doi: 10.1111/j.1365-294X.2010.
04958.x
De T och, M., Boeckx, P., Cnudde, C., Van Gansbeke, D., Van eusel, A., Vincx,
M., e al. (2012). Biocon e sion o a y acids a he basis o ma ine ood webs:
insigh s om a compound-speci ic s able iso ope analysis. Ma . Ecol. P og. Se .
465, 53–67. doi: 10.3354/meps09920
Deagle, B. E., Ja man, S. N., Coissac, E., Pompanon, F., and Tabe le , P. (2014).
DNA me aba coding and he cy och ome c oxidase subuni I ma ke : no a
pe ec ma ch. Biol. Le . 10:20140562. doi: 10.1098/ sbl.2014.0562
De ien, M., Yang, L., and Hu , J. (2017). Lipid bioma ke s and spec oscopic
indices o iden i ying o ganic ma e sou ces in aqua ic en i onmen s: a
e iew. Wa e Res. 112, 58–71. doi: 10.1016/j.wa es.2017.01.023
Douce , F. R., Faus ino, P. J., Sabsabi, M., and Lyon, R. C. (2008). Quan i a i e
molecula analysis wi h molecula bands emission using lase -induced
b eakdown spec oscopy and chemome ics. J. Anal. A . Spec om. 23, 694–701.
doi: 10.1039/B714219F
Dua e, C. M., Delgado-Hue as, A., An on, A., Ca illo-de-Albo noz, P., López-
Sando al, D. C., Agus í, S., e al. (2018). S able Iso ope (δ13C, δ15N, δ18O, δD)
composi ion and nu ien concen a ion o ed sea p ima y p oduce s. F on .
Ma . Sci. 5:298. doi: 10.3389/ ma s.2018.00298
Dua e, C. M., and K ause-Jensen, D. (2017). Expo om seag ass meadows
con ibu es o ma ine ca bon seques a ion. F on . Ma . Sci. 4:13. doi: 10.3389/
ma s.2017.00013
Dua e, C. M., Losada, I. J., Hend iks, I. E., Maza asa, I., and Ma bà, N. (2013). The
ole o coas al plan communi ies o clima e change mi iga ion and adap a ion.
Na . Clim. Change 3, 961–968. doi: 10.1038/nclima e1970
E e shed, R. P., Bull, I. D., Co , L. T., C ossman, Z. M., an Dongen, B. E., E ans,
C. J., e al. (2007). “Compound-speci ic s able iso ope analysis in ecology and
paleoecology,” in S able Iso opes in Ecology and En i onmen al Science, eds R.
Michene and K. Laj ha (Hoboken, NJ: Blackwell Publishing L d), 480–540.
doi: 10.1002/9780470691854.ch14
Fou qu ean, J. W., Dua e, C. M., Kennedy, H., Ma bà, N., Holme , M., Ma eo,
M. A., e al. (2012). Seag ass ecosys ems as a globally signi ican ca bon s ock.
Na . Geosci. 5, 505–509. doi: 10.1038/ngeo1477
Fou qu ean, J. W., and Sch lau, J. E. (2003). Changes in nu ien con en and s able
iso ope a ios o C and N du ing decomposi ion o seag asses and mang o e
lea es along a nu ien a ailabili y g adien in Flo ida Bay, USA. Chem. Ecol.
19, 373–390. doi: 10.1080/02757540310001609370
F y, B. (2013). Al e na i e app oaches o sol ing unde e mined iso ope
mixing p oblems. Ma . Ecol. P og. Se . 472, 1–13. doi: 10.3354/meps
10168
F y, B., and She , E. B. (1989). “δ13C measu emen s as indica o s o ca bon low
in ma ine and eshwa e ecosys ems,” in S able Iso opes in Ecological Resea ch,
eds P. W. Rundel, J. R. Ehle inge , and K. A. Nagy (New Yo k, NY: Sp inge ).
F on ie s in Ma ine Science | www. on ie sin.o g 7May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 8
Ge aldi e al. Finge p in ing Blue Ca bon
Gache , M. S., Schube , A., Cala co, S., Bocca d, J., and Ge sch, J. (2017). Ta ge ed
me abolomics shows plas ici y in he e olu ion o signaling lipids and unco e s
old and new endocannabinoids in he plan kingdom. Sci. Rep. 7:s e41177.
doi: 10.1038/s ep41177
Goldbe g, C. S., Tu ne , C. R., Deine , K., Klymus, K. E., Thomsen, P. F., Mu phy,
M. A., e al. (2016). C i ical conside a ions o he applica ion o en i onmen al
DNA me hods o de ec aqua ic species. Me hods Ecol. E ol. 7, 1299–1307.
doi: 10.1111/2041-210X.12595
G eine , J. T., Wilkinson, G. M., McGla he y, K. J., and Eme y, K. A. (2016). Sou ces
o sedimen ca bon seques e ed in es o ed seag ass meadows. Ma . Ecol. P og.
Se . 551, 95–105. doi: 10.3354/meps11722
Haddad, R. I., and Ma ens, C. S. (1987). Biogeochemical cycling in an o ganic- ich
coas al ma ine basin: 9. Sou ces and accumula ion a es o ascula plan -
de i ed o ganic ma e ial. Geochim. Cosmochim. Ac a 51, 2991–3001. doi: 10.
1016/0016-7037(87)90372-3
Hayes, M. A., Jesse, A., Hawke, B., Baldock, J., Tabe , B., Locking on, D., e al.
(2017). Dynamics o sedimen ca bon s ocks ac oss in e idal we land habi a s
o Mo e on Bay, Aus alia. Glob. Change Biol. 23, 4222–4234. doi: 10.1111/gcb.
13722
He, D., Mead, R. N., Belicka, L., Pisani, O., and Ja é, R. (2014). Assessing sou ce
con ibu ions o pa icula e o ganic ma e in a sub opical es ua y: a bioma ke
app oach. O g. Geochem. 75, 129–139. doi: 10.1016/j.o ggeochem.2014.06.012
Hondula, K. L., and Pace, M. L. (2014). Mac oalgal suppo o cul u ed ha d
clams in a low ni ogen coas al lagoon. Ma . Ecol. P og. Se . 498, 187–201.
doi: 10.3354/meps10644
Hondula, K. L., Pace, M. L., Cole, J. J., and Ba , R. D. (2014). Hyd ogen iso ope
disc imina ion in aqua ic p ima y p oduce s: implica ions o aqua ic ood web
s udies. Aqua . Sci. 76, 217–229. doi: 10.1007/s00027-013-0331-6
Howa d, J., Su on-G ie , A., He , D., Kleypas, J., Landis, E., Mcleod, E., e al.
(2017). Cla i ying he ole o coas al and ma ine sys ems in clima e mi iga ion.
F on . Ecol. En i on. 15:42–50. doi: 10.1002/ ee.1451
Ish-Shalom-Go don, N., Lin, G., and da Sil ei a Lobo S e nbe g, L. (1992). Iso opic
ac iona ion du ing cellulose syn hesis in wo mang o e species: salini y
e ec s. Phy ochemis y 31, 2623–2626. doi: 10.1016/0031-9422(92)83598-S
Ja é, R., Mead, R., He nandez, M. E., Pe alba, M. C., and DiGuida, O. A.
(2001). O igin and anspo o sedimen a y o ganic ma e in wo sub opical
es ua ies: a compa a i e, bioma ke -based s udy. O g. Geochem. 32, 507–526.
doi: 10.1016/S0146-6380(00)00192-3
Johnson, B. J., Moo e, K. A., Lehmann, C., Bohlen, C., and B own, T. A. (2007).
Middle o la e Holocene luc ua ions o C3 and C4 ege a ion in a No he n
New England Sal Ma sh, Sp ague Ma sh, Phippsbu g Maine. O g. Geochem.
38, 394–403. doi: 10.1016/j.o ggeochem.2006.06.006
Kelleway, J. J., Sain ilan, N., Mac eadie, P. I., Baldock, J. A., and Ralph, P. J. (2017).
Sedimen and ca bon accumula ion a y among ege a ion assemblages in a
coas al sal ma sh. Biogeosci. Discuss. 2017, 1–26. doi: 10.5194/bg-2017-15
Kennedy, H., Beggins, J., Dua e, C. M., Fou qu ean, J. W., Holme , M., Ma bà, N.,
e al. (2010). Seag ass sedimen s as a global ca bon sink: iso opic cons ain s.
Glob. Biogeochem. Cycles 24:GB4026. doi: 10.1029/2010GB003848
Kha e, N., and Cha u edi, S. K. (2012). T acing he signa u e o a ious
on al sys ems in s able iso opes (oxygen and ca bon) o he plank onic
o amini e al species Globige ina bulloides in he Sou he n Ocean (Indian
Sec o ). Oceanologia 54, 311–323. doi: 10.5697/oc.54-2.311
K ause-Jensen, D., and Dua e, C. M. (2016). Subs an ial ole o mac oalgae
in ma ine ca bon seques a ion. Na . Geosci. 9, 737–742. doi: 10.1038/ngeo
2790
K ause-Jensen, D., La e y, P., Se ano, O., Ma bà, N., Masque, P., and Dua e,
C. M. (2018). Seques a ion o mac oalgal ca bon: he elephan in he blue
ca bon oom. Biol. Le . 14:20180236. doi: 10.1098/ sbl.2018.0236
Ladd, S. N., and Sachs, J. P. (2015). In luence o salini y on hyd ogen iso ope
ac iona ion in Rhizopho a mang o es om Mic onesia. Geochim. Cosmochim.
Ac a 168, 206–221. doi: 10.1016/j.gca.2015.07.004
Landenma k, H. K. E., Fo gan, D. H., and Cockell, C. S. (2015). An es ima e o he
o al dna in he biosphe e. PLoS Biol. 13:e1002168. doi: 10.1371/jou nal.pbio.
1002168
La sen, T., Bach, L. T., Sal a eci, R., Wang, Y. V., Ande sen, N., Ven u a, M., e al.
(2015). Assessing he po en ial o amino acid 13C pa e ns as a ca bon sou ce
ace in ma ine sedimen s: e ec s o algal g ow h condi ions and sedimen a y
diagenesis. Biogeosciences 12, 4979–4992. doi: 10.5194/bg-12-4979-2015
La sen, T., Ven u a, M., Ande sen, N., O’B ien, D. M., Pia kowski, U., and
McCa hy, M. D. (2013). T acing ca bon sou ces h ough aqua ic and e es ial
ood webs using amino acid s able iso ope inge p in ing. PLoS One 8:e73441.
doi: 10.1371/jou nal.pone.0073441
López-Me ino, L., Se ano, O., Adame, M. F., Ma eo, M. Á, and Ma ínez Co izas,
A. (2015). Glomalin accumula ed in seag ass sedimen s e eals pas al e a ions
in soil quali y due o land-use change. Glob. Plane . Change 133, 87–95. doi:
10.1016/j.gloplacha.2015.08.004
Lo elock, C. E., Ree , R., and Ball, M. C. (2017). Iso opic signa u es o s em
wa e e eal di e ences in wa e sou ces accessed by mang o e ee species.
Hyd obiologia 803, 133–145. doi: 10.1007/s10750-017-3149-8
Mac eadie, P. I., T e a han-Tacke , S. M., Baldock, J. A., and Kelleway, J. J. (2017).
Con e ing beach-cas seag ass w ack in o biocha : a clima e- iendly solu ion
o a coas al p oblem. Sci. To al En i on. 574, 90–94. doi: 10.1016/j.sci o en .
2016.09.021
Ma chand, C., Lallie -Ve gès, E., and Bal ze , F. (2003). The composi ion o
sedimen a y o ganic ma e in ela ion o he dynamic ea u es o a mang o e-
inged coas in F ench Guiana. Es ua . Coas . Shel Sci. 56, 119–130. doi:
10.1016/S0272-7714(02)00134-8
Ma chand, C., Lallie -Ve gès, E., Disna , J.-R., and Ké a is, D. (2008). O ganic
ca bon sou ces and ans o ma ions in mang o e sedimen s: a ock-e al
py olysis app oach. O g. Geochem. 39, 408–421. doi: 10.1016/j.o ggeochem.
2008.01.018
Mcleod, E., Chmu a, G. L., Bouillon, S., Salm, R., Bjö k, M., Dua e, C. M., e al.
(2011). A bluep in o blue ca bon: owa d an imp o ed unde s anding o he
ole o ege a ed coas al habi a s in seques e ing CO2. F on . Ecol. En i on.
9:552–560. doi: 10.1890/110004
Meie -Augens ein, W., Hobson, K. A., and Wassenaa , L. I. (2013). C i ique:
measu ing hyd ogen s able iso ope abundance o p o eins o in e o igins o
wildli e, ood and people. Bioanalysis 5, 751–767. doi: 10.4155/bio.13.36
Monc ei , C. A., and Sulli an, M. J. (2001). T ophic impo ance o epiphy ic algae
in sub opical seag ass beds: e idence om mul iple s able iso ope analyses.
Ma . Ecol. P og. Se . 215, 93–106. doi: 10.3354/meps215093
Moo e, J. W., and Semmens, B. X. (2008). Inco po a ing unce ain y and p io
in o ma ion in o s able iso ope mixing models. Ecol. Le . 11, 470–480. doi:
10.1111/j.1461-0248.2008.01163.x
Nellemann, C., Co co an, E., Dua e, C. M., Valdés, L., De Young, C., Fonseca,
L., e al. (2009). Blue ca bon - he Role o Heal hy Oceans in Binding Ca bon.
A ailable a : h p://hdl.handle.ne /20.500.11822/18520 (accessed June 4, 2017).
O eska, M. P. J., Wilkinson, G. M., McGla he y, K. J., Bos , M., and McKee, B. A.
(2018). Non-seag ass ca bon con ibu ions o seag ass sedimen blue ca bon.
Limnol. Oceanog . 63, S3–S18. doi: 10.1002/lno.10718
O iz, J. E., Mo eno, L., To es, T., Vegas, J., Ruiz-Zapa a, B., Ga cía-Co és, Á,
e al. (2013). A 220 ka palaeoen i onmen al econs uc ion o he Fuen illejo
maa lake eco d (Cen al Spain) using bioma ke analysis. O g. Geochem. 55,
85–97. doi: 10.1016/j.o ggeochem.2012.11.012
Pe e son, B. J., and F y, B. (1987). S able iso opes in ecosys em s udies. Annu. Re .
Ecol. Sys . 18, 293–320. doi: 10.1146/annu e .es.18.110187.001453
Ree , R., A wood, T. B., Sampe -Villa eal, J., Adame, M. F., Sampayo, E. M., and
Lo elock, C. E. (2017). Using eDNA o de e mine he sou ce o o ganic ca bon
in seag ass meadows. Limnol. Oceanog . 62, 1254–1265. doi: 10.1002/lno.10499
Rees, H. C., Maddison, B. C., Middledi ch, D. J., Pa mo e, J. R. M., and Gough, K. C.
(2014). Re iew: he de ec ion o aqua ic animal species using en i onmen al
DNA – a e iew o eDNA as a su ey ool in ecology. J. Appl. Ecol. 51,
1450–1459. doi: 10.1111/1365-2664.12306
Roden, J. S., Lin, G., and Ehle inge , J. R. (2000). A mechanis ic model o
in e p e a ion o hyd ogen and oxygen iso ope a ios in ee- ing cellulose.
Geochim. Cosmochim. Ac a 64, 21–35. doi: 10.1016/S0016-7037(99)00195-7
Rubens ein, D. R., and Hobson, K. A. (2004). F om bi ds o bu e lies: animal
mo emen pa e ns and s able iso opes. T ends Ecol. E ol. 19, 256–263. doi:
10.1016/j. ee.2004.03.017
Ruppen hal, M., Oelmann, Y., and Wilcke, W. (2013). Op imized demine aliza ion
echnique o he measu emen o s able iso ope a ios o nonexchangeable H in
soil o ganic ma e . En i on. Sci. Technol. 47, 949–957. doi: 10.1021/es303448g
Sain ilan, N., Roge s, K., Mazumde , D., and Wood o e, C. (2013). Alloch honous
and au och honous con ibu ions o ca bon accumula ion and ca bon s o e in
sou heas e n Aus alian coas al we lands. Es ua . Coas . Shel Sci. 128, 84–92.
doi: 10.1016/j.ecss.2013.05.010
F on ie s in Ma ine Science | www. on ie sin.o g 8May 2019 | Volume 6 | A icle 263
ma s-06-00263 May 20, 2019 Time: 15:45 # 9
Ge aldi e al. Finge p in ing Blue Ca bon
San ini, N. S., Ree , R., Locking on, D. A., and Lo elock, C. E. (2015). The
use o esh and saline wa e sou ces by he mang o e A icennia ma ina.
Hyd obiologia 745, 59–68. doi: 10.1007/s10750-014-2091-2
Sikes, E. L., Uhle, M. E., Nodde , S. D., and Howa d, M. E. (2009). Sou ces o
o ganic ma e in a coas al ma ine en i onmen : e idence om n-alkanes and
hei δ13C dis ibu ions in he Hau aki Gul , New Zealand. Ma . Chem. 113,
149–163. doi: 10.1016/j.ma chem.2008.12.003
Silliman, J. E., Meye s, P. A., and Bou bonnie e, R. A. (1996). Reco d o pos glacial
o ganic ma e deli e y and bu ial in sedimen s o Lake On a io. O g. Geochem.
24, 463–472. doi: 10.1016/0146-6380(96)00041-1
Sjög en, P., Edwa ds, M. E., Gielly, L., Langdon, C. T., C oudace, I. W., Me kel,
M. K. F., e al. (2016). Lake sedimen a y DNA accu a ely eco ds 20 h Cen u y
in oduc ions o exo ic coni e s in Sco land. New Phy ol. 213, 929–941. doi:
10.1111/nph.14199
Smale, D. A., Moo e, P. J., Quei ós, A. M., Higgs, N. D., and Bu ows,
M. T. (2018). App ecia ing in e connec i i y be ween habi a s is key o
blue ca bon managemen . F on . Ecol. En i on. 16:71–73. doi: 10.1002/ ee.
1765
Smi h, B. N., and Eps ein, S. (1970). Biogeochemis y o he s able iso opes o
hyd ogen and ca bon in sal ma sh bio a. Plan Physiol. 46, 738–742. doi:
10.1104/pp.46.5.738
So o, D. X., Koehle , G., Wassenaa , L. I., and Hobson, K. A. (2017). Re-e alua ion
o he hyd ogen s able iso opic composi ion o ke a in calib a ion s anda ds o
wildli e and o ensic science applica ions. Rapid Commun. Mass Spec om. 31,
1193–1203. doi: 10.1002/ cm.7893
S ukel, M. R., Aluwiha e, L. I., Ba beau, K. A., Chekalyuk, A. M., Goe icke, R.,
Mille , A. J., e al. (2017). Mesoscale ocean on s enhance ca bon expo due
o g a i a ional sinking and subduc ion. P oc. Na l. Acad. Sci. U.S.A. 114,
1252–1257. doi: 10.1073/pnas.1609435114
Tanne , B. R., Uhle, M. E., Mo a, C. I., Kelley, J. T., Schuneman, P. J., Lane,
C. S., e al. (2010). Compa ison o bulk and compound-speci ic δ13C analyses
and de e mina ion o ca bon sou ces o sal ma sh sedimen s using n-alkane
dis ibu ions (Maine, USA). Es ua . Coas . Shel Sci. 86, 283–291. doi: 10.1016/
j.ecss.2009.11.023
Thomsen, P. F., Mølle , P. R., Sigsgaa d, E. E., Knudsen, S. W., Jø gensen, O. A.,
and Wille sle , E. (2016). En i onmen al dna om seawa e samples co ela e
wi h awl ca ches o suba c ic, deepwa e ishes. PLoS One 11:e0165252. doi:
10.1371/jou nal.pone.0165252
Thomsen, P. F., and Wille sle , E. (2015). En i onmen al DNA - An eme ging ool
in conse a ion o moni o ing pas and p esen biodi e si y. Biol. Conse . 183,
4–18. doi: 10.1016/j.biocon.2014.11.019
T e a han-Tacke , S. M., Mac eadie, P. I., Sande man, J., Baldock, J., Howes, J. M.,
and Ralph, P. J. (2017). A global assessmen o he chemical ecalci ance o
seag ass issues: implica ions o long- e m ca bon seques a ion. F on . Plan
Sci. 8:925. doi: 10.3389/ pls.2017.00925
Ve heyden, A., Helle, G., Schlese , G. H., Dehai s, F., Beeckman, H., and Koedam,
N. (2004). Annual cyclici y in high- esolu ion s able ca bon and oxygen iso ope
a ios in he wood o he mang o e ee Rhizopho a muc ona a.Plan Cell
En i on. 27, 1525–1536. doi: 10.1111/j.1365-3040.2004.01258.x
Volkman, J. K. (2006). Ma ine O ganic Ma e : Bioma ke s, Iso opes and DNA.
Be lin: Sp inge Science & Business Media.
Wang, Q., Lu, H., Chen, J., Hong, H., Liu, J., Li, J., e al. (2018). Spa ial dis ibu ion
o glomalin- ela ed soil p o ein and i s ela ionship wi h sedimen ca bon
seques a ion ac oss a mang o e o es . Sci. To al En i on. 613–614, 548–556.
doi: 10.1016/j.sci o en .2017.09.140
Wei, L., Locking on, D. A., Poh, S.-C., Gaspa on, M., and Lo elock, C. E. (2013).
Wa e use pa e ns o es ua ine ege a ion in a idal c eek sys em. Oecologia 172,
485–494. doi: 10.1007/s00442-012-2495-5
Wylie, L., Su on-G ie , A. E., and Moo e, A. (2016). Keys o success ul blue
ca bon p ojec s: lessons lea ned om global case s udies. Ma . Policy 65, 76–84.
doi: 10.1016/j.ma pol.2015.12.020
Ya es, M. C., F ase , D. J., and De y, A. M. (2019). Me a-analysis suppo s u he
e inemen o eDNA o moni o ing aqua ic species-speci ic abundance in
na u e. En i on. DNA. doi: 10.1002/edn3.7
Yoccoz, N. G., B å hen, K. A., Gielly, L., Haile, J., Edwa ds, M. E., Gosla , T., e al.
(2012). DNA om soil mi o s plan axonomic and g ow h o m di e si y. Mol.
Ecol. 21, 3647–3655. doi: 10.1111/j.1365-294X.2012.05545.x
Zanden, V. B. H., So o, D. X., Bowen, G. J., and Hobson, K. A. (2016). Expanding
he iso opic oolbox: applica ions o hyd ogen and oxygen s able iso ope
a ios o ood web s udies. F on . Ecol. E ol. 4:20. doi: 10.3389/ e o.2016.
00020
Zhang, Y., Du, J., Ding, X., and Zhang, F. (2016). Compa ison s udy o sedimen a y
humic subs ances isola ed om con as ing coas al ma ine en i onmen s by
chemical and spec oscopic analysis. En i on. Ea h Sci. 75:378. doi: 10.1007/
s12665-016-5263-8
Zido n, C. (2016). Seconda y me aboli es o seag asses (Alisma ales and
Po amoge onales; Alisma idae): chemical di e si y, bioac i i y, and ecological
unc ion. Phy ochemis y 124, 5–28. doi: 10.1016/j.phy ochem.2016.02.004
Con lic o In e es S a emen : The au ho s decla e ha he esea ch was
conduc ed in he absence o any comme cial o inancial ela ionships ha could
be cons ued as a po en ial con lic o in e es .
Copy igh © 2019 Ge aldi, O ega, Se ano, Mac eadie, Lo elock, K ause-Jensen,
Kennedy, La e y, Pace, Kaal and Dua e. This is an open-access a icle dis ibu ed
unde he e ms o he C ea i e Commons A ibu ion License (CC BY). The use,
dis ibu ion o ep oduc ion in o he o ums is pe mi ed, p o ided he o iginal
au ho (s) and he copy igh owne (s) a e c edi ed and ha he o iginal publica ion
in his jou nal is ci ed, in acco dance wi h accep ed academic p ac ice. No use,
dis ibu ion o ep oduc ion is pe mi ed which does no comply wi h hese e ms.
F on ie s in Ma ine Science | www. on ie sin.o g 9May 2019 | Volume 6 | A icle 263
