What’s so special about Seawater?. Aquarium Chemistry.

What’s so What’s so special special aboutabout

Seawater?Seawater?

Aquarium ChemistryAquarium Chemistry

Water Quality: Nitrogen Water Quality: Nitrogen CycleCycle

badmanstropicalfish.com (originally from www.hagen.com)

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What do we mean by a What do we mean by a “cycled” aquarium?“cycled” aquarium?

A “cycled” aquarium is one that has an established A “cycled” aquarium is one that has an established population of the bacteria that convert ammonium to nitrite population of the bacteria that convert ammonium to nitrite and nitrite to nitrate.and nitrite to nitrate.

Let’s take a closer look at each step.Let’s take a closer look at each step.

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Step 1 – Ammonium NHStep 1 – Ammonium NH44 Ammonium is an ion that is fairly non-toxic to Ammonium is an ion that is fairly non-toxic to

fish. However it easily changes to a highly toxic fish. However it easily changes to a highly toxic form, ammonia NHform, ammonia NH33, which can stress and kill fish , which can stress and kill fish quickly.quickly.

If the pH is acidic (<7) the ammonium ion is If the pH is acidic (<7) the ammonium ion is favored. When the pH is basic (>7), the favored. When the pH is basic (>7), the ammonium ion is quickly turned to ammonia, ammonium ion is quickly turned to ammonia, which is deadly for the fish. which is deadly for the fish.

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Steps 2 and 3 – Nitrite (NOSteps 2 and 3 – Nitrite (NO22--) )

and Nitrate (NOand Nitrate (NO33--) )

NitriteNitrite, like ammonia, is also very toxic to , like ammonia, is also very toxic to fish.fish.

NitrateNitrate is less toxic in low to moderate is less toxic in low to moderate concentrations, concentrations, but becomes stressful but becomes stressful as concentrations build up.as concentrations build up.

The bacteria that do these steps of the The bacteria that do these steps of the cycle are cycle are aerobicaerobic. That means they need . That means they need oxygen. oxygen.

Water Quality: Nitrogen Water Quality: Nitrogen CycleCycle

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Some aquaria are simple, some Some aquaria are simple, some funky...funky...

Some are big, but all the principles are the same Some are big, but all the principles are the same

the Osaka Aquarium (seen here), boasts a tank of 1.4 the Osaka Aquarium (seen here), boasts a tank of 1.4 million gallons and nearly 580 spp.million gallons and nearly 580 spp.

Georgia AquariumGeorgia Aquarium

Georgia AquariumGeorgia Aquarium

Mystic AquariumMystic Aquarium

New England Aquarium

Must maintain a tank ecology that Must maintain a tank ecology that mimics natural habitat.mimics natural habitat.

Controlling water qualityControlling water quality! ! managing the inflow and outflow of managing the inflow and outflow of

nutrients, nutrients, management of waste (nitrogenous)management of waste (nitrogenous) beneficial bacteria populations. beneficial bacteria populations.

Aquarium PartsAquarium Parts

TankTank FilterFilter Gravel/substrateGravel/substrate PumpPump AeratorAerator Reliable water Reliable water

supplysupply

TanksTanks

High quality glassHigh quality glass

-Plexiglass is expensive, but lighter-Plexiglass is expensive, but lighter

Monteray Bay AquariumMonteray Bay Aquarium

No one wants this much water on the carpet!!No one wants this much water on the carpet!!

Plexiglass offers unique design options!

Courtesy: Perigrine Plastics

Aquaria for research: St. Croix Waters Fishery

Filters – 3 (or 4) stagesFilters – 3 (or 4) stages

1.1. Removes solids Removes solids a)a) -small solids called “suspended solids”-small solids called “suspended solids”

b)b) -larger ones called “flocs”-larger ones called “flocs”

2.2. Provides substrate for nitrifiersProvides substrate for nitrifiers

3.3. Binds up chemicalsBinds up chemicals

4.4. Sometimes they can also kill all little crittersSometimes they can also kill all little critters

Gravel/SubstrateGravel/Substrate

Material for nestingMaterial for nesting AestheticsAesthetics NitrificationNitrification ““Live sand”Live sand” Filtration Filtration

Gravel/SubstrateGravel/Substrate

Gravel/SubstrateGravel/Substrate

PVC shavings!PVC shavings!

Activated CarbonActivated Carbon

Media FiltersMedia Filters Bead/Sand/Media filters all use water Bead/Sand/Media filters all use water

pressure to force water through some pressure to force water through some type of media. type of media.

Excellent filtering capacity, esp. for larger Excellent filtering capacity, esp. for larger systemssystems

More maintenance (media changingMore maintenance (media changing

backwashing, etc.)backwashing, etc.)

Mixed media filters

Gravity FiltrationGravity Filtration

Trickle filters/Settling Chamber/Swirl SeparatorsTrickle filters/Settling Chamber/Swirl Separators

Good for nitrification and oxygenation.Good for nitrification and oxygenation. Prone to clogging if primary filtration inefficient.Prone to clogging if primary filtration inefficient.

Over 20 feet tall!

BiofiltersBiofilters

•Help to establish nitrogen cycle.Help to establish nitrogen cycle.

•Break down toxic fish wastes.Break down toxic fish wastes.

What really does the work??What really does the work??

Bacteria!!

UV filtrationUV filtration

Protein Skimmers/ Foam FractionatorsProtein Skimmers/ Foam Fractionators

• Removal of excessive organicsRemoval of excessive organics-decreases B.O.D. and C.O.D.-decreases B.O.D. and C.O.D.

• Increases flocculationIncreases flocculation -decreases solids-decreases solids -increases water clarity-increases water clarity

Liquid OxygenLiquid Oxygen

• Facilitates higher Facilitates higher densitiesdensities

• False security?False security?-increased density -increased density

-increased solids-increased solids -may increase disease-may increase disease

Ozone Ozone

• Increases flocculation Increases flocculation

• Reduces disease Reduces disease outbreakoutbreak

-kills bateria, fungus, -kills bateria, fungus, virusesviruses

• Expensive!!Expensive!!

AerationAeration

Adds dissolved oxygen for specimenAdds dissolved oxygen for specimen Speeds up decompositionSpeeds up decomposition Circulates water (air lift pump)Circulates water (air lift pump)

HH22O moleculeO molecule

HH22O moleculeO molecule One hydrogen H and two oxygen O One hydrogen H and two oxygen O

atoms bonded by sharing electronsatoms bonded by sharing electrons Both H atoms make a positive side, Both H atoms make a positive side,

O side is negative, so it is a: O side is negative, so it is a: Polar Polar moleculemolecule

Hydrogen bondingHydrogen bonding Polarity means Polarity means

small negative small negative charge at O endcharge at O end

Small positive Small positive charge at H endcharge at H end

Attraction Attraction between + and – between + and – ends of water ends of water molecules to each molecules to each other or other ionsother or other ions

Fig. 5.3

Hydrogen bonding: Hydrogen bonding: the result of the result of polaritypolarity

Hydrogen bonds are weaker than Hydrogen bonds are weaker than covalent bonds but still strong enough covalent bonds but still strong enough to result in:to result in: High surface tensionHigh surface tension Cohesion and adhesionCohesion and adhesion High solubility of chemical compounds in High solubility of chemical compounds in

waterwater Solid, liquid, gas at Earth’s surfaceSolid, liquid, gas at Earth’s surface Unusual thermal propertiesUnusual thermal properties Unusual density Unusual density

Water molecules in different Water molecules in different states of matterstates of matter

Fig. 5.5

Changes of state due to adding Changes of state due to adding or subtracting heator subtracting heat

Heat is energy of moving moleculesHeat is energy of moving molecules Calorie is amount of heat needed to Calorie is amount of heat needed to

raise the temperature of 1 gram of raise the temperature of 1 gram of water by 1water by 1oo C C

Temperature is measurement of Temperature is measurement of average kinetic energyaverage kinetic energy

Unusual thermal properties of Unusual thermal properties of HH22OO HH22O has high boiling pointO has high boiling point HH22O has high freezing pointO has high freezing point Most HMost H22O is in the form of water O is in the form of water

(liquid) on Earth’s surface (good for (liquid) on Earth’s surface (good for life)life)

High High latent (hidden) heatslatent (hidden) heats of of Vaporization/condensationVaporization/condensation Melting/freezingMelting/freezing EvaporationEvaporation

Fig. 5.6

Unusual thermal properties of Unusual thermal properties of HH22OO Water high Water high heat capacityheat capacity

Which is the amount of heat Which is the amount of heat required to raise the temperature required to raise the temperature of 1 gram of any substance 1of 1 gram of any substance 1oo C C

Water can take in/lose lots of heat Water can take in/lose lots of heat without changing temperature without changing temperature muchmuch

Rocks low heat capacityRocks low heat capacity Rocks quickly change temperature as Rocks quickly change temperature as

they gain/lose heatthey gain/lose heat

Specific Heat Values

  Specific Heat

Material (cal/g °C) (J/kg K)

Aluminum 0.215 900

Copper 0.092 385

Iron 0.107 448

Lead 0.031 130

Brass 0.092 385

Magnesium 0.245 1030

Zinc 0.093 390

Styrofoam 0.27 1131

Air 0.240 1006

Water 1.000 4190

Ice 0.500 2095

Global thermostatic Global thermostatic effectseffects

Moderate temperature on Earth’s Moderate temperature on Earth’s surfacesurface Equatorial oceans (hot) don’t boilEquatorial oceans (hot) don’t boil Polar oceans (cold) don’t freeze solidPolar oceans (cold) don’t freeze solid

Marine effectMarine effect Oceans moderate temperature changes Oceans moderate temperature changes

day/night; different seasonsday/night; different seasons Continental effectContinental effect

Land areas have greater range of Land areas have greater range of temperatures day/night and during temperatures day/night and during different seasonsdifferent seasons

Density of Various MaterialsMaterial g/cm3

Aluminum 2.7

Copper 8.96

Iron 7.87

Lead 11.3

Brass 8.4

Magnesium 1.74

Zinc 7.14

Lead 11.3

Water 1.00

Ice 0.917

Density of waterDensity of water

Density of water increases as Density of water increases as temperature decreasestemperature decreases

Density of ice is less than density Density of ice is less than density of waterof water

From 4From 4ooC to 0C to 0ooC density of water C density of water decreases as temperature decreases as temperature decreasesdecreases

Density of waterDensity of water

Fig. 5.10

Where did Earth’s water come from?

(MinuteEarth)(MinuteEarth)

A second opinion (NatGeo)(NatGeo)

Ocean water compositionOcean water composition

What are the differences?

Salinity :Salinity :Total amount of solid material dissolved in water- Total amount of solid material dissolved in water- Typical salinity is 3.5% or 35 Typical salinity is 3.5% or 35 ‰‰ or parts per thousand (ppt) = grams of salt per kilogram of or parts per thousand (ppt) = grams of salt per kilogram of water g/Kg\water g/Kg\Six elements make up 99% of dissolved solids in seawaterSix elements make up 99% of dissolved solids in seawater

Fig. 5.12

Measuring salinityMeasuring salinity Can be measured by specific gravity, Can be measured by specific gravity,

electrical conductivity or by electrical conductivity or by refraction of lightrefraction of light

We will measure with a We will measure with a refractometerrefractometer in parts of salt per in parts of salt per thousand of water (the unit being ppt thousand of water (the unit being ppt or or ‰))

Salinity variationsSalinity variations Open ocean salinity 33 to 38 Open ocean salinity 33 to 38 ‰

Coastal areas salinity varies Coastal areas salinity varies more widely, especially in more widely, especially in estuariesestuaries

What factors would cause salinity What factors would cause salinity to vary?to vary?

Processes that add/subtract Processes that add/subtract water from oceanswater from oceans

Precipitation (rain Precipitation (rain or snow)or snow)

Runoff (river Runoff (river flow)flow)

Melting icebergsMelting icebergs Melting sea iceMelting sea ice

EvaporationEvaporation Formation of Formation of

sea icesea ice

Salinity decreases through:

Salinity increases through:

Deep ocean variation of Deep ocean variation of salinitysalinity

Surface ocean salinity is variableSurface ocean salinity is variable Deeper ocean salinity is nearly Deeper ocean salinity is nearly

the same (polar source regions the same (polar source regions for deeper ocean water)for deeper ocean water)

HaloclineHalocline, rapid change of , rapid change of salinity with depthsalinity with depth

SalinitSalinity y versus versus depthdepth

Fig. 5.22

Hydrologic cycle describes Hydrologic cycle describes recycling of water near Earth’s recycling of water near Earth’s surfacesurface

Fig. 5.15

Surface ocean variation of Surface ocean variation of salinitysalinity

Fig. 5.21

Surface ocean variation of Surface ocean variation of salinitysalinity Polar regionsPolar regions: salinity lower, lots of : salinity lower, lots of

rain/snow and runoffrain/snow and runoff Mid-latitudesMid-latitudes: salinity higher, high : salinity higher, high

rate of evaporationrate of evaporation EquatorEquator: salinity lower, lots of rain: salinity lower, lots of rain

Thus, salinity at surface varies Thus, salinity at surface varies primarily with latitudeprimarily with latitude

Density of seawaterDensity of seawater Ocean layered according to densityOcean layered according to density

1.022 to 1.030 g/cm1.022 to 1.030 g/cm3 3 surface seawatersurface seawater Density seawater controlled by Density seawater controlled by

temperature and salinitytemperature and salinity Salinity greatest influence on density in Salinity greatest influence on density in

polar oceanspolar oceans Polar ocean is isothermalPolar ocean is isothermal

SalinitSalinity y versus versus depthdepth

Fig. 5.22

Our ocean is Our ocean is layered layered due to density due to density

differences at depthdifferences at depth PycnoclinePycnocline, abrupt change of density , abrupt change of density

with depthwith depth ThermoclineThermocline, abrupt change of , abrupt change of

temperature with depthtemperature with depth HaloclineHalocline, abrupt change of salinity , abrupt change of salinity

with depthwith depth High latitude oceansHigh latitude oceans

IsothermalIsothermal IsopycnaIsopycnal l

Fig. 5.23

Sound and light of seawaterSound and light of seawater

Due to density, the Due to density, the speed of speed of sound sound in salt water is 1500 m/secin salt water is 1500 m/sec As opposed to 340 m/sec in airAs opposed to 340 m/sec in air

The The index of refraction index of refraction of light in of light in water is 1.33, as you increase the water is 1.33, as you increase the salinity, you increase the indexsalinity, you increase the index

Ocean pHOcean pH

8.18.1

Residence time and steady Residence time and steady statestate

Fig. 5.16

Fig. 5.18

Carbonate bufferingCarbonate buffering

Carbon emissions and poor Carbon emissions and poor little ocean critterslittle ocean critters

Carbon dioxide is a natural by-Carbon dioxide is a natural by-product of combustion.product of combustion.

In low pH water, organisms cannot In low pH water, organisms cannot form calcium carbonate shells.form calcium carbonate shells.

What do the data show?What do the data show?

Can you drink seawater?Can you drink seawater?

Can you drink seawater?Can you drink seawater? No, it will make your cells No, it will make your cells

plasmolyze and you will die. plasmolyze and you will die. But we now can remove salt But we now can remove salt from seawaterfrom seawater

Or can we?Or can we?

Can you drink seawater?Can you drink seawater? No, it will make your cells No, it will make your cells

plasmolyze and you will die. But plasmolyze and you will die. But we now can remove salt from we now can remove salt from seawaterseawater

Or can we?Or can we? DistillationDistillation--most common --most common

processprocess ElectrolysisElectrolysis Reverse osmosisReverse osmosis Freeze separationFreeze separation

Trapped on a desert island? Trapped on a desert island? what do you do?what do you do?

Fig. 5.24