Produtores e bacérias

N2 dissolvido

NH4

DIN

Terra

NH3

Azotoparticulado

Sedimentos

Guano, pescasAzoto

Atmosférico

DON

NO3

NH4 fixado

DON

N part.não-vivo

DesnitrificaçãoMorte

Regeneração

Decomp.

Excreção

RegeneraçãoAdsorção

Trocaiónica

Nitrificação

Amónificação

Desnitrificação

Decomp. Decomp.

Absorção

Uptake

Fixação Pastagem

Sedimentação

Fontes telúricas

Volatilização

Hetero.

Consumidores

Ciclo do azoto no ambiente marinhoCiclo do azoto no ambiente marinho

Transformações de azotoTransformações de azoto

Azoto

orgânico Uptake e redução assimilativa nas

células

Redução dissimilativa

Fixação de N2

ExcreçãoDecomposição

Uptake

NitrificaçãoNitrificação

NH4+

Azotoamoniacal

NH2OHHidroxilamina

N2Azoto

gasoso

N2OÓxidonitroso

NOÓxidonítrico

NO2-

Nitrito

NO3-

Nitrato

3 5Estado de oxidação

-3 -1 0 1 2

Fenchel & Blackburn, 1979. Bacteria and mineral cycling. Academic Press.

GIS GIS -- Annual mean DIN in the Tagus estuaryAnnual mean DIN in the Tagus estuaryLimit of

salt intrusion

Lisboa

Atlanticocean

0 10 20 km

DIN (umol l-1)

NO3NO3--Temperature relationship for the eastern Temperature relationship for the eastern tropical Pacific (Aug.tropical Pacific (Aug.--Nov. 86Nov. 86--88)88)

n = 503550

40N

itrat

e µ

20

30

M

10

0 10 25 305 15 3520Temperature oC

Fiedler Fiedler et alet al., 1991 ., 1991 -- Limnol. & Oceanog. 36, p. 1834Limnol. & Oceanog. 36, p. 1834--5050

Redfield ratioRedfield ratioDefinitions

“Standard” ratio of C:N:P“Standard” ratio of C:N:P

May be expressed in atoms or massMay be expressed in atoms or mass

Derives from the constancy of composition of biotaDerives from the constancy of composition of biota

C:N:PC:N:P 106:16:1106:16:1 (in atoms)(in atoms)

C:N:PC:N:P 45:7:145:7:1 (in mass)(in mass)

Oxygen may also be included, considering that for every Oxygen may also be included, considering that for every carbon atom fixed two oxygen atoms are producedcarbon atom fixed two oxygen atoms are produced

CO2 + 2H2A CH2O + 2A + H2OLight

Pigments

O:C:N:PO:C:N:P 212:106:16:1212:106:16:1

PO4 PO4 -- NO3 relationship for the easternNO3 relationship for the easterntropical Pacific (Aug.tropical Pacific (Aug.--Nov. 1986Nov. 1986--88)88)

Phos

phat

e µM

0

1

2

3

4

0 10 20 30 40Nitrate µM

50

n = 5338

Fiedler Fiedler et alet al., 1991 ., 1991 -- Limnol. & Oceanog. 36, p. 1834Limnol. & Oceanog. 36, p. 1834--5050

SiO4 SiO4 -- NO3 relationship for the easternNO3 relationship for the easterntropical Pacific (Aug.tropical Pacific (Aug.--Nov. 1986Nov. 1986--88)88)

0

20

40

60

0

Silic

ate µM

10 20 30 40Nitrate µM

50

n = 5324

Fiedler Fiedler et alet al., 1991 ., 1991 -- Limnol. & Oceanog. 36, p. 1834Limnol. & Oceanog. 36, p. 1834--5050

N:P ratio for the Tagus Estuary N:P ratio for the Tagus Estuary –– Data from B2KData from B2K

60

70

80

n=184145 stations~20 years

DIN

(µm

ol L

-1)

100

90

50

40

30

20

10

00 1 2 3 4 5 6 7 8 9 10

PO43- (µmol L-1)

N:P ratio for Carlingford LoughN:P ratio for Carlingford Lough

80

100

n=85973 stations4 years (1990-1993)

DIN

(µm

ol L

-1) 120

60

40

20

00 1 2 3 4 5

PO43- (µmol L-1)Data from BarcaWin2000

N:P ratio for Carlingford LoughN:P ratio for Carlingford LoughSeasonal breakdownSeasonal breakdown

n=85973 stations4 years (1990-1993)

N/P

ratio

(no

units

)

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200 250 300 350 400

Strong N limitation

Julian dayData from BarcaWin2000

Limit ofsalt intrusion

Lisboa

Atlanticocean

0 10 20 km

GIS GIS -- Annual mean DIP in the Tagus Annual mean DIP in the Tagus estuaryestuary

DIP (umol l-1)

Limit ofsalt intrusion

Lisboa

Atlanticocean

0 10 20 km

GIS GIS -- Annual mean Redfield ratio (N/P)Annual mean Redfield ratio (N/P)for the Tagus estuaryfor the Tagus estuary

N/P (mol ratio)

Balanço de massa de cargas e regeneração de nutrientes em Narragansett Bay, E.U.A.

Entradas anuais(106 at-g ano-1)

Azoto Fósforo

EntradasFixação 0.2 -Precipitação 2.8 0.19Runoff 16.2 0.8Rios 235 17.3Efluentes 278 21.7

• Total 532 39.9

RegeneraçãoMenhaden 0.8 0.1Ctenóforos 8.1 0.8Zooplâncton 98.5 -Bentos 264 41.1

• Total 371 42Nixon, 1981. Remineralization and nutrient cycling in coastal marine ecosystems. In Neilson & Cronin (Eds.) , Estuaries and Nutrients, Humana, p. 111-138.

Balanço de massa de azoto. Todos os valores em kg N ano-1

Sippewissett marsh, E.U.A.

Entradas Saídas Trocaslíquidas

Precipitação 380 380Águas subterrâneas 6120 6120Fixação de N2 3280 3280Trocas pela maré 26200 31600 -5350Desnitrificação 6940 -6940Sedimentação 1295 -1295Outras 9 26 -17

• Total 35990 39860 -3870

% de troca biótica 9 18% de troca física 91 82

Valiela & Teal (1979). The nitrogen budget of a salt marsh ecosystem, Nature 280, 652-656.Sinais menos indicam exportação do sapal.

DIN mass balance for Cala do Norte (kg N yDIN mass balance for Cala do Norte (kg N y--11))

Advection-dispersion Internal processesInputsUpstream 817642Effluents 3109278Sub-total 3926920

OutputsDownstream -3607087Sub-total -3607087

Total 319833

SourcesPhyto mortality 29740Zoo sloppy grazing 2819Zoo metabolism 9632Zoo excretion 321Zoo mortality 1527Sub-total 44039

SinksGross primary prod. -363834Sub-total -363834

Total -319795

Total 38 kg y-1 (approx. zero) ∆N -0.113 µat g DIN l-1 y-1

Phytoplankton N mass balance for Cala Phytoplankton N mass balance for Cala do Norte (gN mdo Norte (gN m--22 yy--11))

Advection-dispersion Internal processesSourcesNet primary prod. 20.53Sub-total 20.53

SinksNatural mortality - 2.73Grazing - 1.44Sub-total - 4.17

Total 16.36

InputsUpstream 11.88Sub-total 11.88

OutputsDownstream - 28.24Sub-total - 28.24

Total - 16.36

Total 0 g m-2 y-1 Stock 0.150 gN m-2

Redfield ratioRedfield ratioCaveat

This is a mean ratio, in some cases the variance will This is a mean ratio, in some cases the variance will be large!be large!

ApplicationsAnalysing the food chain (planktonic or detrital)Analysing the food chain (planktonic or detrital)Determining nutrient limitationDetermining nutrient limitationPerforming mass balances, i.e. Understanding stocks Performing mass balances, i.e. Understanding stocks and fluxesand fluxesManagement of input and uptakeManagement of input and uptakeUnderstanding the role of autochtonous production, Understanding the role of autochtonous production, external inputs and export (outwelling)external inputs and export (outwelling)Ecological modelling (currency tables)Ecological modelling (currency tables)

OAERRE data + TICOR dataOAERRE data + TICOR dataChlorophyll Chlorophyll aa and nutrientsand nutrients

Maximum spring phytoplankton (chl a µg L-1)

0

5

10

15

20

25

30

GF

KFFC

Ria Formosa

HF

GM Tejo

SadoMondego

Mira*1

Guadiana

Ria de Aveiro*2

50 60 70 80

Tett, P., Gilpin, L., Svendsen, H., Erlandsson, C.P., Larsson, U., Kratzer, S., Fouilland, E., Janzen, C., Lee, J., Grenz, C., Newton, A., Ferreira, J.G., Fernandes, T., Scory, S., 2002. Eutrophication and some European waters of restricted exchange. Submitted to Coastal and Nearshore Oceanography, NEEA, and unpublished work from TICOR.

Maximum winter DIN (µM)

0 10 20 30 40 90 100 110 120

*1 – Chlorophyll determined from graphical data*2 – Nitrate, not DIN