Index 291methyl mercury, lipophilic and toxic 172
methylation, of ionic mercury 172
Mexico, Gulf of, human effects on 235, 236
increased nitrate in Mississippi River 235
loss of wetlands 235
stratified water column 235
mica group 76, 88
sheet silicates 104–5
two to one clay mineral structure 88–9, 91–2, 91
microbial reduction, of arsenic-bearing iron oxides
179–80
microbiological activity in estuaries 187–9
microorganisms 22
involved in sulphide oxidation 157–8
oceanic
produce organosulphides 42
source of atmospheric trace gases 42
soil, major role in organic matter degradation 103–4
used in in situbioremediation by biostimulation 131–3
mid-ocean ridges 4
basaltic crust
convection of seawater through 208–9, 209
emplacement 208
hydrothermal springs
acidification of waters 209–11, 210
contain dissolved transition metals 210
location of known hydrothermal systems 211
mineral reaction kinetics and solution saturation 99
insoluble minerals 99 , 107
soluble minerals, dissolution rate 99
mineralization 125, 128 , 130
Minimata disease (mercury poisoning) 172, 174
mining activities
and acid mine drainage 156–9
acidity can be neutralized 159
problem of abandoned mines 159
mixed-layer clays 92
mole/molar concentration/molarity 22
molecular sieves 126
molecules
biologically important, synthesis in specialized
environments likely 9
chiral and achiral280 –1
molecular bonds 19
polarity of 26, 69B, 122
see alsoorganic molecules
mollisols 118
molybdenum (Mo) 218, 219
monomer silicates 73, 75
dissolution rates 94
Montreal Protocol 63
MSA seemethane sulphonic acid (MSA)
N : P ratio, in freshwater 163
n-alkanes 24, 24
naphthalene, biodegradation pathways for 135, 137, 137
needle muds202–3
Negro, River (Rio Negro) 151
low ionic strength 147
weathering of evaporite minerals in the catchment
160–1, 160
neutrons 3
nickel (Ni), sinking to Earth’s centre 2
nitrate (NO 3 )
as a free radical 265
increase in river concentration 237
Great Ouse River 168, 168
little effect on ocean concentrations 221–2
increased concentrations in regional seas 233–7
total oceanic inventory 235
washes out of soils and into rivers 167–8
nitric acid 266
nitro functional group 25 , 26
nitrogen compounds
damaging to ozone 45
oxidized 57
nitrogen dioxide (NO 2 ) 266
nitrogen fixation 167
bacterial 229
nitrogen (N) 164, 166–8
active nitrogen chemistry in soils 41–2
chemistry and cycling complex in natural waters
166–7, 166
cycled as organic tissues 218–19
nitrogen oxides (NOx)
can damage pigments 56
reactions in photochemical smog 50, 51 , 54
Nitrosomonas 41
nitrous oxide (NO 2 ) 258, 259
biological source for 41, 45
byproduct of denitrification 162
noble (inert) gases 16
non-metals 17 , 18, 20–1
nuclear weapons testing, radionuclides from 28
nutrient transport, affected by lakes and dams 169
nutrients
and eutrophication 163–70
artificially introduced nutrients 163
and plant growth 245
riverine, impacting regional seas 233–5, 234 , 236
ocean chemistry, anthropogenic effects on 233–7
oceans 9, 181–238
acidity of 26, 40
agents of material transport to 67–8, 68
central, atmospheric input of particle-reactive metals
225
chemical cycling of major ions 191–215
circulation
effects of deep mixing at high latitudes 230–1, 230 ,
231 , 232
effects on trace element distribution 229–31
CO 2 uptake
box model for248–9
limited by slow downward mixing of surface waters
246–7
continental shelf areas, important for carbonate
deposition 201
cool, dense deep waters
in hydrothermal circulation 208–9, 209 , 210
hydrothermal plumes scavenge elements from 226–7
deep, carbonate sedimentation in 201