know-hows

Primary production in ocean is much faster: phytoplankton has shorter life span than trees

but

Net Primary Production Ocean ≅Net Primary Production Land (~52 x 1015g C yr-1)

1. infiltration of cold seawater

2. heating of seawater > 400°C

3. dissolution of metals from volcanic rocks

4. precipitation of element-enriched hot water at contact with cold seawater

5. black smokers -> massive sulfides

• potential: ca. 600 mio tons of sulfides

Free ion activity model

for many metals free ions rather than total metal concentration are responsible for biological effects

1. transport of metal from solution to the biological surface (advection, diffusion)

2. diffusion of metal through protective outer layer

3. sorption/surface complexation of the metal at passive binding sites within the protective layer, or at sites on the outer surface of the cell membrane

4. uptake of metal -> consequent biol effects on metabolism, ps are important

1. Plants die in surface layers where there is light

2. Plants get eaten in surface layer by grazers (Protozoa, zooplankton)

→ reduced forms of N are excreted (NH3, urea)

3. Or plants sink and die, or die and sink, or animals die and sink, etc…

that is, PON sinks into deeper water below euphotic zone

1. rivers

2. aeolian dust

3. hydrothermal sources

•

In seawater containing O 2 , NO 3 is the thermodynamically stable

form (not N 2

•

Most N is in the form of N 2 because of kinetic limitations (energy

required to break N triple bond)

•

When seawater is anoxic, [O 2 = 0, then NO 3 is the next most

favoured oxidising agent

1. Apatite (95 of alls P in earth crust)

2. Vivianite (in reducing fresh water sediments)

Slow part of the cycle:

• uplifting of sedimentary rock, occurs over

• geological timescale

• Rock weathering provides P back to the oceans

Fast parts of the cycle:

• Uptake by algae

• Uptake by bacteria

• Regeneration by bacteria

• Regeneration by other heterotrophs

• Interaction with solid phases

uptake:

• CO2 from volcanic

• sedimentary org c weathering

• metamorphism and deep diagenesis (also CH4)

  
  

  sink:

• CO2 and CaCO3 burial

• subduction of CO2 and CaCO3

• convert of CO2 to dissolved HCO3- by Ca-Mg silicate weathering

  
  

is difficult to sample this circulating water directly…. more diffuse

circulation through sediments

•

laboratory experiments at these temperatures take much longer

because of slower kinetics

•

generally studied by looking at the chemical alteration of basalts

based on drilled samples

Results of these analyses show both similarities and differences

with high temperature reactions.

Ca

2+ and Si are both released to the ocean as with high T reactions

DOC levels very low in vent fluids

K

may be removed at low temperatures: DOC is added

> Heat capacity (atmosphere)

> 50 x CO2content(atmosphere)

97.4% (rest groundwater and continental ice, mantle and crust excluded)

mEq is used because it takes elements into charge, other than mmol

(2 Na+ < 2 Mg++ and not the same)

Bsp: conservative, non-reactive

Uranium, Kalium, Calcium

Source at the surface, decay, removal or degradation within ocean

Manganese

Aluminium (high in surface bc of dust and sediments, low in mit latitudes bc get used up by organisms)

source at seafloor, or within the ocean interior, “recycled”, nutrient type

Nitrate, Phosphate, all “organic” nutrients

uptake of CO2by phytoplankton and transfer to deep ocean through settling

not influenced by anthropogenic CO2 uptake

uptake of CO2by gas solubility processes with subsequent transfer by water mass movement

influenced by anthropogenic CO2 uptake

Dust= 8% Al, 3.5% Fe

no nitrogen and phosphorus

Volcanoes can have a effect on primary production,

but other nutrients are needed and effect is short lived

(fass-Modell)

ions: atoms with more or fewer electrons than protons

isotopes: atoms, containing the same number of protons but different number pf neutrons (different atomical weight)

molecules: combound with more than one atom

smaller than 0.2 or 0.4 µm is dissolved

everything above is particulate

buffering

it is a basin for particles and particles are not removed therefore it stays salty

major input: river

major output: sediments

residence time: 0.1 x 10^6 years

others mean by 10 x 10^6 years

so short because it gets used up by shells for calciumcarbonate reactions

replicate -> mean -> standarddeviation -> repeat analysis

reference material

1. use of absolute salinity (S,A) to describe salinity of seawater

2. use of conservative temperature to replace potential temperature (represents heat content of seawater)

3. TEOS-10 properties of SW derived from a Gibbs function -> consistent with each other

physical: uptake by gas solubility -> watermass movement

biological: uptake by phytoplankton -> setting in deep ocean (1% of OM reaches the seafloor)

1. exchange within sediments

2. biological and human activity

3. changes in pH and O2 levels (redox)

-> happens within estuaries

Cations: Na, K, Mg, Ca

Anions: Cl, SO4-, HCO3-, Br, F

Riverwater: HCO3- (Anion)

SW: Cl

residence time >> ocean mixing time (most of anions, Na, Mg, K, Cl, SO4-)

residence time =/< ocean mixing time (HCO3, Ca)

• chemically/biologically reactive

• particle reative= short res. time

• decay (radioactive)

• vary independently from salinity

1. controlls freezing point

2. density

3. solubility of gases

4. tracer for ocean circulation

1. rivers

2. atmospheres

3. hydrothermal vents

4. erosions

1. seasalt particles: Na, K, Ca, Mg

2. atmospheric gases: SO4,2-,, NO3-,, NH4+

1. human impact

2. evaporation

3. weathering of rocks

4. biol processes in soils

congruent: simple dissolution (products end up in solution)-> calcite, olivine

incongruent: dissolution + reprecipitation forms secondary minerals -> K-feldspar, volcanic glass

1. Calcium, Magnesium, Bicarbonate

2. Chloride

3. Potassium

4. Sulfate

5. inorganic carbon

= avoid CaCO3 formation (in washing powder)

Secondary mineral formed by weathering of primary minerals (like Feldspar)

transported in ocean in large amounts but rapidly deposited in estuaries

O2 > Si > Al > Fe

-> SW penetrates crust -> heating -> reaction with basalt -> expulsion of hot altered SW at mid ocean ridges ->

1. cooling by circulating water

2. 3He (3He from degassing, 4He from decay)

3. metalliferous sediments

4. vent communities (biological signature)

1. Basalt (Uptake of Mg2+), release of H+, Ca2+

2. precipitation of SO42- during recharge

3. mobilization of metals (Bsp: Fe, Mn, Cu, Zn)

4. Inpit of H2S of sulphides and mantle

-> chemoautotrophy

• no light

• chemical reactions as energy source

• support oxidation of H2S, CH4, Fe2+, Mn2+

Black: precipitation of hydroxides (iron+sulfur)+ sulfides

white: mainly calcium and silicon

• main removal of Mg

• significant input of Fe, Mn

• density neutrally buoyant

• hydrothermal fluent reflect reaction between Sw and basalt

• fluid dramatically altered

• dominant process: oxidation of Fe2+ to Fe oxides

1. volcano

2. ridges and seafloor

3. sediments = weathering

1. ocean burial

2. weathering

3. subduction

respiration-sinking-deposition-burial

(redfield ratio!)

60

C:N:P = 106:16:1

O2: 138

Calcite (CaCO3): Coccolithophores, Foraminifera

Aragonite (CaCO3): green algae, corals

Opaline silica (SiO2): Diatoms, Radiolaria

Ksp: solubility konstant

Saturation index: tendency to precipitate

1

<1 = dissolve

CaCO3/C org -> marine snow

increases with decreasing temp

increases with increasing pressure

increases with increasing co2 conc

saturation horizon: depth at which water becomes undersaturrated

calcite compemsation depth

all CaCO3 dissolved, no more calcite accumulation

more sediments in pacific (= more acidic) because CCD is deeper

oxidation: loss of electrons

reduction: gain of electrons

transfer between chemical species

90% recycling

10% export (external N supply)

global calcium budget net at steady state: increased loss

apparent oxygen utilization:

O2 saturation - O2 measured

1. sewage

2. agriculture

3. chemicals

4. oil

break down of organic C while providing energy

-> thermodinamically favourable

• Thermo: how things are at equilibrium

• kin: how fast reactions occur

1. ocean circulation

2. biological activity

3. water column recycling processes

N2 > NO3 > DON > NH4 > NO2

most limiting nutrient, also due to Fe shortage

1. deep ocean

2. atmosphere

1. nitrogen fixation: requieres lot of energy and Fe input for nitrogenose (biological or by fixation)

2. Nitrification: in presense of O2 -> yields energy -> “reversal assimilation” process

1. denitrification: dissimilation, main loss pathway, increases P concentration

PON + NO3 -> N2 + …

“Anaerobic ammonium oxidation”

NO2 + NH4 -> N2 + …

waste treatment plants

Fertilisation and Emission

-> haber-bosch

• Population and flux decrease with depth

  –

  particles “consumed” on the way down

  –

  due to bacterial degradation of organic matrix

  –

  exponential process (like radioactive decay)

  empirical relationship leads to organic carbon

  decomposition constant of ~2.38 d 1

• biological packaging

• made from bacterial mucous , trapped particles, etc

• isolated biogeochemical environment

• separate, concentrated bacterial communities

• strong chemical gradients and enhanced concentrations

• effective vertical transport of material

• mineral particle ballasting to give larger density difference;

1. particle size

2. material (density contrast)

3. shape

4. stokes law (force of viscosity)

Collect settling

particles;



Use radioactive

tracers;



Use mass balance

methods;



Satellite data and

modelling;

1. preservation issues

   1. bacterial degradation

   2. swimmers (visible and criptic)

2. geometric issues

   1. non-settling of material into cup

   2. pertubation

   3. funnel of origin effects

   4. wrong angle

• not in steady state bc of glacial-interglacial sea-level changes affecting shallow water carbonate accumulation

• stronger removal thn supply leading to sodium replacing ca in water column

• -> steady state takes time

1. Rate of O 2 removal > rate of O 2 supply

2. Respiration (oxidation of organic material) removes oxygen

3. Photosynthesis and Gas Exchange with atmosphere supply

   oxygen; this is in surface waters (only)

4. Mixing and ocean circulation transport oxygen to the sub surface ocean

measured with AOU

occurs

• high phostosynthesis (if higher than surface saturation)

• mixing

• (only in surface areas)

• 0 m: low in tropics bc fast exchange with atmosphere

• 50 m: more on pole regions than at 0 m

• 1000 m: seeing watermass ages (older= less oxygen)

• 3500 m: clearer watermass ages

96 % as aspatite

PO4 > HPO4 > H2PO4

1. river discharge

2. upwelling

1. OM burial

2. apatite burial

3. adsorption on Fe oxides (When Fe reduced, P released and vice versa)

Fast parts:

1. uptake by bacteria

2. regeneration by bacteria

low parts:

1. uplifting of sediments

2. weathering

1. weathering

2. aeolian dust

3. rivers

4. hydrothermal vents

5. discussing of bSi when diatoms die

export of Bsi, returned to surface by upwelling -> biol. pump -> recycling

• decreases with increasing temp

• decreases with increasing salinity

= upwelling regions

source: saturated = PP sw > pp a

sink: undersaturated = andersherum

if gas transfer is by molecular diffusion across a stagnant boundary layer (<- slow!)

thickness in atmosphere and ocean, where gases can diffuse only by molecular diffusivity

1. chem reactions -> gradients

2. sea state (turbulences, bubbles …)

3. organic films (affect turbulences)

4. molecular sizes (schmidt number)

kinematic viscosity: mollecules move slower in honey than water

time depends on wind speed and mixed layer depth

1. changes in temp & salinity at surface

2. atmosphere pressure changes

3. air bubble injection (storms), high pressure

4. biological processes (respiration)

5. mixing of watermasses

summer: 100-120% (PS,warming, bubble injection)

winter: < 100%: respiration and cooling

blooming can occur only if mixed layer is less than critical depth -> shallowing of surface mixed layer

free iron activity model

• for many metals: free ions rather than total metal concentration are responsible for biological effects

• step 1: ransport of the metal from solution to the biological surface (advection, diffusion)

• step 2: Diffusion of metal through protective outer layer

  • Organisms have a protective polysaccharide or glycoprotein layer (cell wall for m.o. and higher plants (lignin, cellulose); mucus for animals)

  • negative charge (oxygen containing functional groups; non chelating)

• Step 3 Sorption/surface complexation of the metal at passive binding sites within the protective layer, or at sites on the outer surface of the cell membrane

  • Cell membranes are composed of lipids (fats and waxes) and proteins

  • Lipids: phospholipids, cholesterol, glycolipids

  • Most common phospholipid is phosphatic acid ------> hydrophobic and hydrophilic end  bi-layer formed with non polar groups in interior region

• step 4: 4: Uptake of metal (transport across membrane)  consequent biological effects on metabolism, photosynthesis are important

• maintain overall structural integrity of membrane

• act as enzymes (ATPase at mitochondrial membrane)

• act as carrier for ions and other molecules across membrane

(step 3 of metal organism interactions)

• Simple diffusion (oxygen, water..) through protein lined channels

• Facilitated diffusion (from higher to lower concentration, but substance is first complexed by carrier molecule (probably protein) (glucose transport)

• Active transport: against concentration gradient -> cost energy Na, K, ATPase -> Na, K pump

A. metal speciation in outside environment

B. metal interaction with biological membrane separating outside inside

C. metal partitioning in organism and its biological effects

• if not on active site then the sorption/complexation follows the Langmuir isotherm

• If on active site the complexation and uptake follows linear relation ship with free metal activity

  
  

• This could be a physiologically active site at cell surface (fish gill) ------> direct response

• or X corresponds to transport site that allows M to traverse cell membrane (subsequent biological effects)

• or X could be transport site normally used by essential micronutrient.

• Binding at cell surface by M would inhibit the supply of the essential element and induce nutrient deficiency (e.g. Mn/Cu and Fe/Cd phytoplankton)

-> needs to be done quickly

1. plasma membrane is primary site for metal interaction with biota

2. metal-membrane interactions are surface complexatio reaction, forming M-X-cell (metals being hydrophilic)

3. metal transport in solution, formation of M-X-cell is rapid (equilibrium established) -> faster than biological response

4. biological response (uptake/nutrition/toxicity) is dependent on concentration of M-X-cell surface complex

5. in the range of metal concentration of toxicological interes, the concentration of free sites (-X) remains virtually constant and (M-X-cell) follows those (Mz+) in solution

6. metals do not induce changes to plasma membrane during exposure time

• phytochelatins

  • synthesized from gluthation by enzyme phytochelatin synthase (needs metal for activity)

  • produced by plants and algae to chelate heavy metals (bind)

• glutathione (GSH)

  • naturally occurring compound, major thiol (R-SH) in animals, plants, phytoplankton, bacteria

both are metal-binding peptides: produced by eularyotic organisms -> marine phytoplankton

SH- groups

1. metal detoxification mechanism

2. regulation of intracellular metal concentrations-homeostasis

• static (steady state) equeation applied to dynamic wax and wane of plankton blooms

• limitations presumed independent while within living cell they are all interacting

• light

• nitrate

• phosphate

• iron

• silicate

also:

• Mn

• Cu

• Zn

• Co

  
  

real biometals: shorter res time

• Mn, Fe, Co, Ni, Cu, Zn, Cd

abtiotic metals: longer res time

• Ag, Hg, Pb

• small 4-6 µm diameter: single cells

  • never Fe-limited but grazer controlled

• large 30 x 80 µm: chain-forming and individua cells

  • mostly fe-limited except after fe supply

• old paradigm:

  • coastal diatom require more Fe than oceanic diatom

• new paradigm:

  • ok but third class of large oceanic diatoms having high Fe requirement

  • these large organisms are driving export

• 7000 m kevlar cable with internal signal cables

• Epoxy coated stainless steel prototype frame; final type of titanium or carbon fibre, within own clean van

• (CTD) muat be ultraclean to allow measurements of trace elements

• !!! cerified standard is urgently needed!

• biogeochemically:

  • diss oxygen and co2 necessary for life

  • signatures of biological processes

• usage as tracers for circulation

  • esp helium 3

• CO2: ocean is huge carbon reservoir

  • >25% of anthropogenic co2

  • by air-sea gas exchange

• Solubilitiesof different gases vary widely

• Gas solubility increases with increasing molecular weight of the gas

• Gas solubility decreases with increasing temperature

• gas solubility decreases with increasing salinity

• Ar and O2have quite similar solubility behaviour

• Heavier, more polar gases are more soluble

• More soluble gases have greater temperature dependence

• deep ocean waters only equilibrate (exchange gases) with atm at sea-surface -> conc of non reactive gases are established at pressures that are close to atm pressure

• some gas exchange takes place between sw and air within bubbles that have been transported to depth of ~10 m

  • takes place at elevated presszres (hydrostatic pressure and surface tension effects)

sediments and ocean floor can act as source or sink of gases

1. N2produced by denitrification in sediments (NO3⇒N2)

2. O2consumed due to sediment respiration

3. CH4produced from methanogenesis

4. 3He from mantle released by hydrothermal fluids

5. 222Rn from radioactive decay in sediments

1. chemical reaction

   1. in situ reactions could increase gradients

2. organic films

   1. concentrated near surface

   2. affect turbulence and wave spectra

3. the molecular size and so gas diffusivity in water (D)

   1. -> dependence on the schmidt number

4. sea state

   1. near surface turbulence

   2. surface area/roughness

   3. bubbles produced by waves

   4. sea spray

      
      

• radon method (226Ra -> 222Rn)

• global 14C inventories

  • 14C from nuclear weapon tests

• deliberate tracer elements

  • SF6 and 3He injection

• direct flux measurements

  • eddy correlation etc

• Changes in T and S at the sea-surface over time

• Atmospheric pressure changes (up to 12% in storms, 3-4% seasonally)

• air Injection (bubbles)

• Biological processes (e.g. respiration)

• Mixing of water masses (solubility non-linear f(T,S))

pressure of air in bubbles due to:

1. atm pressure

2. hydrostatic oressure (depth)

3. pressure due to surface tension effects

-> higher pressure forces gases into solution, can cause significant supersaturation of dissolved gases (relative to equilibrium at 1 atm pressure)

2 extreme cases:

1. some bubbles collapse/ dissolve completely

2. some bubbles dissolve partially

• comservative gases

• -> given sufficient time: surface layers of ocean reach equi with atm in absence of air injection

timescale can be derived from:

1. depth of surface mixed layer Zm (length)

2. the gas exchange coefficient, eG (length/time) (dependend on wind speed)

-> Zm/eG units of Time

• ps in surface waters produce oxygen

• POM formed and is respired in-situ or sinks

• sinking material is respired where no new oxygen from atm ca readily be obtained

• hence, non-equilibrium conditions can develop

  
  

• 100-120 % in summer (PS, warming, bubble injection)

• <100% in winter (respiration, cooling but counter acted by bubble injection)

a

pparent oxygen utilization

= difference between equilibrium O2 conc and actual oxygen concentration

• o2 conc are close to steady state

• respiration in deep ocean is balanced by resupply of oxygen from surface, physical transport (ocean currents, mixing)

• abs o2 levels at any depth reflects the cumulative amount of respiration that has ocurred in water since it lost contact with sea-surface (the atm)

• sometimes o2 is depleted: where organic carbon supply is high relative to rate of resupply of o2 from surface

1. major nutrient for selected organisms (diatoms, sponges, radiolarians)

2. diatoms can account for up to 40% of marine primary production

3. plays an important role in biological pump

land:

• si minerals (fe, mg and ca combined)

• quartz (pure sio2, stable cristalline)

ocean:

• suspended or particulate

  • From weathering of rocks: quartz, feldspar, clay minerals

  • Framework silicate minerals are thermodynamically very stable, therefore, on biological time scales their dissolution in the ocean is very slow

  • Biogenic silica: amorphous (non crystalline) SiO 2 (opal) from plankton

• dissolved

  • mainly from dissolution of amorphous silica

  • SiO 2 (s) + 2 H 2 O → Si(OH 4) (aq)

  • Silicic acid (often referred to as silicate)

  • Not known if there are dissolved organic forms (likely negligible)

• Reactive Si (Si that can be utilised by organisms) enters the ocean from rivers, Aeolian dust and hydrothermal sources.

• Inputs of reactive Si to the ocean only account for about 6 Tmol Si yr 1

• Environmental parameters

  • Temperature and Pressure

• Intrinsic properties of the frustules

  • Silicification (thickness, surface area)

• Ecosystem processes

  • bacterial activity

  • grazing and faecal pellet formation

  • aggregation

• high temp: enhance bacterial degradation of protective organic layer which encases diatoms frustules

• higher temp: enhances diatom growth rates leading to lesss silificied frustules

1. diatoms have faster maximum growth rate

2. diatoms are limited by silicic acid if scarce

   1. tend to dominate ecosystems when si abundand

• rain rate of opal:

  • overlying productivity (and si supply)

• degree of preservation during sinking and shallow/surface sediements

  • concentration in underlying waters; temp type of particles (wall thickness, sinking rate)

• accumulation of other sediments

  • rapid burial? (dilutes but preserves)

• diatoms which grow in high silicate environments develop thicker frustules (more heavily silicified) -> bsp: seen in southern ocean by Fragilariopsis

• francolite (carbonate-fluorapatite)

• formation in sediment or at sediment surface under specific conditions:

  • under high POC and adequate P and Ca contents

  • under weakly reducing conditions

  • often at boundary of oxygen minimum zones

  • -> upwelling areas

fast parts of cycle:

• uptake by algae, by bacteria

• regeneration by bacteria and other heterotrophs

• interaction with solid phases

slow part of the cycle:

• uplifting of sedimentary rock, occurs over geological timescale

• rock weathering provides P back to the oceans