Annex 8 – Hydrosphere
Table of Contents
1. Introduction ...................................................................................................................................2
2. Definition .......................................................................................................................................3
2.1 Activities and flows encompassed by the pool ................................................................................... 3
2.2 Definition of boundaries ..................................................................................................................... 4
2.3 Nitrogen species involved ................................................................................................................... 5
3. Internal structure ...........................................................................................................................7
4. Pool description (flows computation, data, models) ........................................................................8
4.1 Overview of the nitrogen flows .......................................................................................................... 8
4.2 Exchanges with the pool Atmosphere (ATHY) .................................................................................. 10
4.3 Exchanges with the pool Energy and fuels (EFHY) ............................................................................ 11
4.4 Exchanges with the pool Humans and settlements (HSHY) .............................................................. 11
4.5 Exchanges with the pool Agriculture (AGHY).................................................................................... 12
4.6 Exchanges with the Forest and semi-natural vegetation (FSHY) ...................................................... 12
4.7 Exchanges with the pool Waste (WSHY) ........................................................................................... 13
4.8 Exchanges with the pool Material and products (MPHY) ................................................................. 13
4.9 Exchanges with the pool Rest of the world (RWHY) ......................................................................... 14
5. Uncertainties ............................................................................................................................... 15
6. References ................................................................................................................................... 16
7. Document version ........................................................................................................................ 16
1
1. Introduction
The Convention on Long-range Transboundary Air Pollution adopted a guidance document to assist in
the calculation of national nitrogen budgets (NNB) (ECE/EB.AIR/119). According to the guidelines, the
NNB must include eight pools that exchange nitrogen or store it in stocks, notably Atmosphere, Energy
and fuels, Humans and settlements, Agriculture, Forest and semi-natural vegetation, Waste, Material
and products, and Hydrosphere (ECE/EB.AIR/119 IV). Exchanges outside national boundaries are
considered as flows from/to the pool Rest of the world.
This document describes the pool Hydrosphere and provides methodologies for the computation of the
major nitrogen flows to the other pools of the NNB. In addition, the document discusses inherent
uncertainties and limitations in the estimation of nitrogen flows and stock changes in the pool.
2
2. Definition
2.1 Activities and flows encompassed by the pool
The pool Hydrosphere consists of all national water bodies that are part of the liquid phase of the
(natural) hydrological cycle1. This includes: glaciers, groundwater, rivers, lakes, estuaries, coastal and
marine waters.
Figure 1 – Nitrogen flows between the Hydrosphere and the other pools of the NNB (including the rest
of the world).
1
For the definition of the hydrological cycle see the Glossary of Terms used in the IPCC Fourth Assessment Report, Glossary of
Synthesis Report, available at http://www.ipcc.ch/publications_and_data/publications_and_data_glossary.shtml (accessed on
20/10/2014)
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2.2 Definition of boundaries
For the inherent difficulty in establishing the boundaries of some water bodies (for example
groundwater bodies, or the water exchange between territorial and international sea water), for the
scope of the NNB we propose the conceptual simplification of the Hydrosphere in three main
compartments: 1) groundwater, 2) surface water and 3) coastal water (including transitional, coastal
and marine water).
For the definition of ‘groundwater’ and ‘surface water’ we refer to the EU Directive 2000/60/EC (Water
Framework Directive, WFD). In the definition of ‘coastal water’ we include the transitional and coastal
water, as defined by the EU Directive 2000/60/EC, and the marine waters, as defined in the EU Directive
2008/56/EC (Marine Strategy Framework Directive, MSFD). The definitions are reported in Table 1.
The boundary of the Hydrosphere with the Rest of the world might be complex for several reasons. First,
the hydrological cycle follows the natural watershed boundaries rather than the national boundaries,
this means that water flows between transboundary aquifers, rivers or lakes can be present. Second, the
extent and feature of aquifers are known only partially. Third, although the limit between territorial and
international water is clearly defined, the water and nitrogen fluxes between the two sea areas are very
complex to be accounted.
Sediments in surface and marine waters are not part of the Hydrosphere pool (or should be part?), but
they are in the national territory. Considering the geological times, the permanent burial of nitrogen in
sediments of water bodies could be considered as an export towards the Rest of the world. However,
when there is the possibility of re-suspension of nitrogen then sediments should be better considered as
a temporal stock change (accumulation in sediments that can be released to the Hydrosphere).
Table 1 – Definition of the simplified conceptual compartments considered in the Hydrosphere pool
(based on the definition of water bodies from EU Directives 2000/60/EC and 2008/56/EC).
Hydrosphere
Definition (from EU legislation)
Groundwater
Groundwater means all water which is below the surface of the
ground in the saturation zone and in direct contact with the ground
or subsoil (Directive 2000/60/EC Article 2(2)).
Surface water
Surface water means inland waters, except groundwater;
transitional waters and coastal waters (Directive 2000/60/EC Article
2(1)).
Inland water means all standing or flowing water on the surface of
the land, and all groundwater on the landward side of the baseline
from which the breadth of territorial waters is measured (Directive
4
2000/60/EC Article 2(3)).
Coastal water
Transitional waters are bodies of surface water in the vicinity of
river mouths which are partly saline in character as a result of their
proximity to coastal waters but which are substantially influenced
by freshwater flows (Directive 2000/60/EC Article 2(6)).
Coastal water means surface water on the landward side of a line,
every point of which is at a distance of one nautical mile on the
seaward side from the nearest point of the baseline from which the
breadth of territorial waters is measured, extending where
appropriate up to the outer limit of transitional waters (Directive
2000/60/EC Article 2(7)).
Marine waters means: (a) waters, the seabed and subsoil on the
seaward side of the baseline from which the extent of territorial
waters is measured extending to the outmost reach of the area
where a Member State has and/or exercises jurisdictional rights, in
accordance with the Unclos, with the exception of waters adjacent
to the countries and territories mentioned in Annex II to the Treaty
and the French Overseas Departments and Collectivities; and (b)
coastal waters as defined by Directive 2000/60/EC, their seabed
and their subsoil, in so far as particular aspects of the
environmental status of the marine environment are not already
addressed through that Directive or other Community legislation
(Directive 2008/56/EC Article 3(1)).
2.3 Nitrogen species involved
Water is the medium of most of the nitrogen fluxes between the Hydrosphere and the other pools. In
water nitrogen can be present in different forms, including NO3, NO2, NH3 and DON, as reported in
Table 2. Nitrogen can also be embedded in the organic matter of the living organisms (phytoplankton,
zooplankton, benthos, fishes, macrophytes, plants, bacteria, etc.) and in the detritus (organic matter?).
In the exchanges between Hydrosphere and atmosphere, the gaseous forms of nitrogen are involved,
such as N2, N2O, NO and NH3.
Table 2 – Form of nitrogen present in the pool Hydrosphere. (to be checked and completed)
Nitrogen forms
Nitrate
Acronym Chemical
formula
NO3
NO3
Nitrite
NO2
NO2
N content State
description
[%]
in aqueous
solution
in aqueous
solution
5
Ammonia
NH3
Dissolved Organic DON
Nitrogen
Nitrogen in organic orgN
matter
NH3
82.35
variable
variable
in aqueous
solution
in aqueous
solution
solid
Living
detritus
organisms,
N2
N2O
NH3
6
3. Internal structure
Three sub-pools:
Table 3 – Sub-pools of the Hydrosphere pool.
ID
8A
8B
8C
GW
SW
CW
Sub-pool
Groundwater
Surface waters
Coastal waters (open to the rest of the world)
Figure 2 – Schematic representation of the sub-pools of the Hydrosphere.
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4. Pool description (flows computation, data, models)
4.1 Overview of the nitrogen flows
This section describes the major flows between the Hydrosphere and the other pools in the NNB,
specifying the flows per sub-pool of the Hydrosphere.
ID
1
2
3
4
5
6*
7*
8*
9*
EF
MP
AG
FS
WS
HS
AT
HY
RW
Pool
Energy and Fuels
Materials and products (not used in your annex!)
Agriculture
Forest and Semi-natural Vegetation
Waste
Humans and Settlements
Atmosphere
Hydrosphere
Rest of the world
8
Table 4 – Nitrogen flows between the Hydrosphere and the other pools of the NNB
Flow name
Poolex
Poolin
Process
Major N
forms (to be
completed)
Sub-pools
involved
Description
Methodology
in Annex
ATHYdep
ATHYfix
AT
AT
HY
HY
deposition
fixation
SW, CW
SW, CW
Dry and wet deposition
N2
N2, N2O
GW, SW, CW
Annex AT
Annex AT
missing
Annex HY
Annex HY
Annex HS
HYATden
HYEFalgae
HSHYsd
HY
HY
HS
AT
EF
HY
denitrification
HSHYurb
HS
HY
HYHSabs
HY
HS
Runoff from paved
areas
Water abstraction
HYHSfish
HY
HS
Fish landing
AGHYleach
AGHYrun
AG
AG
HY
HY
N leaching
N runoff
HYAGabs
HY
AG
Water abstractions
FSHYleach
FS
HY
N leaching
NO3
GW
FSHYrun
FS
HY
N runoff
NO3
SW, (CW)
WSHYsew
WS
HY
Sewage waters
SW, (CW)
WSHYleach
WS
HY
Leaching
GW
HYWS
MPHYfert
HY
MP
WS
HY
SW, CW
SW, CW
HYMPfish
HY
MP
Algae, discarded fish?
Fertilisers for
aquaculture
Fish
HYMPalgae
HY
MP
Algae
SW, CW
RWHYin
RW
HY
Water inflows
RWHYsed
RW
HY
RWHYsea
RW
HY
RWHYfert
RW
HY
HYRWout
HY
RW
Re-suspension from
sediments
Import from the open
sea
Fertilisers for
aquaculture
Water outflows
HYRWsed
HYRWsea
HYRWfish
HY
HY
HY
RW
RW
RW
Burial in sediments
Export to the open sea
Fish trade (export)
Algae for biofuels??
scattered dwellings
GW, (SW),
(CW)
SW, (CW)
NO3, NO2,
DON,
Fish
(proteins)
NO3
NO3
GW, SW
Annex HS
missing
Not estimated
SW, CW
Annex HY
GW
SW, (CW)
Annex AG
Annex AG
GW, SW
SW, CW
All forms
All forms
GW, SW
Aquaculture?
Water abstractions for
irrigation and animal
drinking
Natural background
emissions
Natural background
emissions (ex. leaves)
Treated or untreated
sewage waters (this
should include also
waste from ships)
Leaching from solid
waste
Annex HY
Annex FS
Annex FS
Annex WS
missing treated
waters
Annex WS
Not estimated
Annex MP
Should we differentiate
from fish for HS?
Algae for food &
cosmetics gels??
Transboundary rivers,
lakes and aquifers (&
artificial transfers)
Annex HY
Annex HY
Annex HY
SW, CW
Not estimated
CW
Not estimated
SW, CW
Annex HY
All forms
GW, SW
All forms
SW, CW
CW
SW, CW
Transboundary rivers,
lakes and aquifers (&
artificial transfers)
Annex HY
Not estimated
Not estimated
Annex HY
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Theoretically, the nitrogen balance of the Hydrosphere pool is closed. However, in practice there are
errors, unaccounted flows, and missing or inconsistent data (ECE/EB.AIR/119).
According to the ideal balance equation, the sum of the net nitrogen flows between the Hydrosphere
and the other pools (HYnet, tN/yr) and the change in stock (ΔStock, tN/yr) should be equal to zero:
HYnet + ΔStock = 0
(Eq.1)
In the Hydrosphere the change in stock is represented by changes in the biota (living organisms, fish
stock, aquatic plants) and in the concentration of different nitrogen forms in water (organic, inorganic,
dissolved, particulate)
HYnet is defined as the sum of the net nitrogen flow between Hydrosphere and each of the other pools:
HYnet = ATHYnet + EFHYnet + HSHYnet + AGHYnet + FSHYnet + WSHYnet + MPHYnet + RWHYnet (Eq.2)
The terms of the Eq.2 are expressed in tN/yr and are explained in the following paragraphs.
4.2 Exchanges with the pool Atmosphere (ATHY)
The net nitrogen flow between the Hydrosphere and the Atmosphere pool (ATHYnet) is defined as:
ATHYnet = ATHYdep + ATHYfix – HYATden
(ATHYdep, ATHYfix, HYATden are defined in Table 4)
Flow name
ATHYdep
ATHYfix
HYATden
Method of computation
Annex AT
Annex AT
HYATGWden + HYATSWden +
HYATCWden
Suggested data sources
Uncertainty
10
4.3 Exchanges with the pool Energy and fuels (EFHY)
The net nitrogen flow between the Hydrosphere and the Energy and fuels pool (EFHYnet) is defined as:
EFHYnet = HYBFalgae
(HYBFalgae is defined in Table 4)
Flow name
HYBFalgae
Method of computation
HYBFSWalgae + HYBFCWalgae
Suggested data sources
Uncertainty
4.4 Exchanges with the pool Humans and settlements (HSHY)
The net nitrogen flow between the Hydrosphere and the Humans and settlements pool (HSHYnet) is
defined as:
HSHYnet = HSHYsd + HSHYurb - HYHSabs - HYHSfish
(HSHYsd, HSHYurb, HYHSabs, HYHSfish are defined in Table 4)
Flow name
HSHYsd
HSHYurb
HYHSabs
HYHSfish
Method of computation
Annex HS
Annex HS
Not estimated
HYHSSWfish + HYHSCWfish
Suggested data sources
Uncertainty
11
4.5 Exchanges with the pool Agriculture (AGHY)
The net nitrogen flow between the Hydrosphere and the Agriculture pool (AGHYnet) is defined as:
AGHYnet = AGHYleach + AGHYrun - HYAGabs
(AGHYleach, AGHYrun, HYAGabs are defined in Table 4)
Flow name
AGHYleach
AGHYrun
HYAGabs
Method of computation
Annex AG
Annex AG
Not estimated
Suggested data sources
Uncertainty
4.6 Exchanges with the Forest and semi-natural vegetation (FSHY)
The net nitrogen flow between the Hydrosphere and the Forest and semi-natural vegetation including
soils pool (FSHYnet) is defined as:
FSHYnet = FSHYleach + FSHYrun + HYFSup
(FSHYleach, FSHYrun, HYFSup are defined in Table 4)
Flow name
FSHYleach
FSHYrun
HYFSup
Method of computation
Annex FS
Annex FS
Not estimated
Suggested data sources
Uncertainty
12
4.7 Exchanges with the pool Waste (WSHY)
The net nitrogen flow between the Hydrosphere and the Waste pool (WSHYnet) is defined as:
WSHYnet = WSHYsew + WSHYleach
(WSHYsew, WSHYleach are defined in Table 4)
Flow name
WSHYsew
WSHYleach
HYWS
Method of computation
Annex WS
Annex WS
Not estimated
Suggested data sources
Uncertainty
4.8 Exchanges with the pool Material and products (MPHY)
The net nitrogen flow between the Hydrosphere and the Material and products in industry pool
(MPHYnet) is defined as:
MPHYnet = MPHYfert – HYMPfish - HYMPalgae
(MPHYfert, HYMPfish are defined in Table 4)
Flow name
MPHYfert
HYMPfish
HYMPalgae
Method of computation
Annex MP
HYMPSWfish + HYMPCWfish
Suggested data sources
Uncertainty
13
4.9 Exchanges with the pool Rest of the world (RWHY)
The net nitrogen flow between the Hydrosphere and the Rest of the world pool (RWHYnet) is defined as:
RWHYnet = RWHYin + RWHYfert – HYRWout - HYRWfish
(RWHYin, RWHYfert, HYRWout, HYRWfish are defined in Table 4)
Flow name
RWHYin
RWHYfert
HYRWout
HYRWfish
Method of computation
(RWHYGWin) + RWHYSWin
RWHYSWfert + RWHYCWfert
(RWHYGWout) + RWHYSWout
HYRWSWfish + HYRWCWfish
Suggested data sources
Uncertainty
14
5. Uncertainties
15
6. References
7. Document version
Version: 24/10/2014 (draft)
Authors: Bruna Grizzetti1, Faycal Bouraoui1, Maren Voss2, others?..
1
European Commission Joint Research Centre (JRC), via Fermi, I-21027 Ispra (VA), Italy
2
(please add)
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