1 of 114

Marine Ecology and Physiology

Course Overview

Open Seas

Coral Reefs

Ocean Depths

Primary Production

Marine Microbes

Mangroves

Estuaries

Rocky Shores

Continental Shelves

The Ocean Floor

The Pelagic

Fisheries

Ocean Warming and Acidification

Marine Pollution

Table of Contents

Lecture 1 (Marine Microbes: the most abundant form of marine life) – Strike day .............................................. 1

Lecture 2: Physical and Chemical Oceanography ............................................................................................... 4

Lecture 3 – primary productivity of the oceans ................................................................................................ 10

Lecture 4 : Intertidal Rocky Shores .................................................................................................................. 18

Lecture 5 (Polar Oceans) ................................................................................................................................... 26

Lecture 6 Estuaries, Saltmarshes and Seagrass Beds ........................................................................................ 34

Lecture 7 (MG): Continental Shelves and the Ocean Floor ................................................................................. 41

Lecture 8 (Coral Reefs) ...................................................................................................................................... 48

Lecture 9 : Mangrove Ecosystems ..................................................................................................................... 57

Lecture 10 ......................................................................................................................................................... 64

Lecture 11 (Ecology of the pelagic zone) ........................................................................................................... 70

Lecture 12: Past and future of fisheries ............................................................................................................. 78

Lecture 13 (Ocean warming) ............................................................................................................................. 88

Lecture 14: Ocean acidification (the battle for carbonate) ................................................................................ 97

Lecture 1 (Marine Microbes: the most abundant form of marine life) – Strike day

Aims of the lecture

• Provide an overview of the key microbial players in the ocean

• Provide examples of their significance in the marine environment including: • Autotrophs as primary producers

• Nitrogen fixation

• Decomposition

• Disease • Symbiosis

Representatives from three domains Bacteria, Archaea and Eukarya

SPOTS: San Pedro Ocean Time Series) Microbial Observatory of the University of Southern California

How the interplay between physical, chemical and biological factors influence diversity and productivity in each of these marine ecosystems

2 of 114

Suttle, C. (2007). Marine viruses — major players in the global ecosystem Nature Reviews Microbiology, 5 (10), 801-812 DOI: 10.1038/nrmicro1750

Role of Viruses

• World's Largest, Most Complex Marine Virus Is Major Player in Ocean Ecosystems

• ScienceDaily (Oct. 31, 2010) — UBC researchers have identified the world's largest marine virus--an unusually complex 'mimi-like virus' that infects

an ecologically important and widespread planktonic predator. (Fischer et al., PNAS, vol 107: 19513)

• CroV attacks the small heteroflagellate Cafeteria roenbergensis

• Majority of viruses infect bacteria, arhaea or microeukaryotes: estimated global population is 1031

• Research by Weitz & Wilhelm(2012) Ocean viruses and their effects on microbial communities and biogeochemical cycles.

- recent evidence suggests that viral lysis of microbes changes the relative

distribution of dissolved organic matter with many indirect effects in

ocean ecosystems.

-

The lysis of microbes by viruses releases cellular material into the environment.

Some of this cellular material can be utilized by microbes for subsequent metabolic

processes. Here, we note that available dissolved organic material (DOM) and

particulate organic material (POM) is utilized primarily by heterotrophs (the thicker

arrow leading downward from the DOM/POM pool). Note that many other processes

are not included in this schematic, e.g. sinking out of the system, exudation during

growth, light input, or the influx of inorganic carbon and nutrients. Abbreviations:

DOM, dissolved organic material; POM, particulate organic material.

Prokaryotes: bacteria and archaea: role in marine ecosystems?

• Largest bacterium 0.75 mm.

• Prokaryotes: The unseen majority. Whitman et al. 1998, PNAS 95:6598-6583

• Thiomargarita namibiensis

• Major role as decomposers

• Recycling of nutrients e.g. dissolved organic

matter (DOM)

• DOC in the oceans of the world is one of greatest reserves of organic carbon on our

planet:

DOM, DOC, POM, POC

Refractory or labile?

3 of 114 Significance of Microbial Loop

• Bacterial biomass in open ocean exceeds that of phytoplankton

• Bacteria play key role in carbon flux in oceans

Puffer fish Takifugu niphobles contains symbiotic bacteria that

produce a deadly toxin called tetrodotoxin

Archaea: many are extremophiles: e.g. living in hydrothermal vents, hot springs

• Common in marine environments

• in water and sediments

• Can make up 20% of prokaryotes in particular regions of the

oceans (Karner et al (2001) Nature, 409, 507-510.

Crenarchaeotal abundance in the North Sea between August 2002 and July 2003 as a

response to changing nutrient concentrations.

Wuchter C et al. PNAS 2006;103:12317-12322

Archaeal nitrification in an enrichment culture of a crenarchaeote from the North

Sea.

Evidence from this experiment that archaea may be responsible for ocean

nitrification and bacteria were not.

Important in coastal waters: role in oceanic waters yet to be established

Phytoplankton in the oceans

• Devices for sampling phytoplankton (left) and zooplankton (right, called a Bongo net)

Summary of key primary producers and their roles in oceanic

cycles

• Organic particles sink

• Bacterial decay regenerates nutrients

• Much of this occurs below photic zone

• Nutrients are carried into deep water

These last slides have already been discussed in previous lectures but help you to make the link between material covered.

4 of 114

Complex interactions with biotic and abiotic

variables is reflected in differing

productivity patterns in the major oceans.

So far, we have only discussed photosynthetic organisms. In addition, there

may be many single celled

heterotrophs – they occur in animals guts,

plankton, sediments and seaweed

surfaces.

Foraminifera (planktonic and benthic)

Radiolaria- their shells form siliceous sediment on sea floor when they die

Ciliates – many benthic but may inhabit guts or seas urchins, fish skin etc or

are planktonic like the tintinnid above with vase shaped lorica (case)-

important in microbial loop

Fungal associations in lichens

Animals form symbiotic relationships with algae

Rumpho et al (2000). Plant. Physiol, 123, 29-38.

Further reading

Huber + castro Ch 5

1. Members of the domains Bacteria and Archaea are prokaryotic organisms and

therefore their cells lack a nucleus and other membrane-bound organelles.

2. Symbiotic bacteria may be responsible for toxins (or poisons) in pufferfishes.

3. Not all autotrophic bacteria are photosynthetic. For instance, some derive energy from H2S and other inorganic

compounds.

4. Dinoflagellates are mostly autotrophs but some ingest organic particles. Many are bioluminescent: that is,

capable of producing light.

5. Protozoans such as foraminiferans and radiolarians are unicellular and are therefore included in the

kingdom Protista.

6. Diatom cells are enclosed in cell walls made largely of silicon dioxide, or silicon.

7. Nitrogen fixation is carried out by cyanobacteria.

Ch 15

Lecture 2: Physical and Chemical Oceanography

In this image you can see differences in the concentration of chlorophyll a

indicating differences in productivity in our oceans. We will study how the

interplay between physical, chemical and biological factors influence the

diversity and productivity of different areas. it compares the differences with

vegetation index.

Chlorophyll a is a measure of photosynthetic biomass and therefore indicates the production of new material that fuels

the food chain. - It is the major pigment of every org that p/s

5 of 114 • Here we can see that it is not evenly distributed. There are hot spots and cold spots and these arise due to

interplay with physical and chemistry and biology.

• Chlorophyll a is measured in mg / m3 which is the same mg/ L. – Low concs for the vast majority of our oceans: if

you go to a polluted lake that is green due to algal blooms in freshwater: conc can be higher (1000mg/m3) à

freshwater lakes have higher concs.

• The vast majority of our oceans are v. low concs.

• Coastal margins get up to 1mg/m3 and above, ~5mg/m3

• There is variation and where it is low, they have tried to see if we can boost this because the chlorophyll a is

fundamental to all processes: needed by orgs at bottom of the food chain.

• About 50% of productivity is in oceans, 50% is on land – the oceans cover such a huge area.

Terminology for different regions of the oceans

• Litoral zone: the area that generally gets uncovered on a

daily basis (when tides go out). This exposes the orgs

that live here to all sorts of gradients of exposure

• Neritic = near shore waters; oceanic = waters in ocean.

• Pelagic: the whole water region (neritic + oceanic)

• There are subtidal regions and then continental slope,

then deeper regions.

• Anything that chooses to live at the bottom = Benthic.

• Planktonic: free-swimming in oceans; Benthic on the

bottom (Attached or free living)

• Photic: the photic zone is often measured to find out

the level of light penetration; it varies in depth dep on location, could be deeper, ~1%

light level 200m down.

Water is an exceptional solvent

• It dissolves more substances and in greater quantities than any other common liquid:

salts, sugars, acids, alkalis, and some gases including oxygen and carbon dioxide

• Cell components such as polysaccharides, proteins and DNA are dissolved in water and

derive their structure and activity from interactions with water

River run-off, volcanic activity, rain and snow, hydrothermal vents make the sea salty

- Run off is important

- Lot of problems for things getting into the oceans (biosolids = sewage, sometimes

put on land then can run in)

- Microplastics.

- The two key things we have most problems are nitrate (No3n) + phosphate –

inorganic forms. These key nutrients arrive through river run off (sometimes

nitrogen from rain + snow)

- Hydrothermal vents might also add sulfide + chlorides

- These all contribute to salinity of oceans + you can use a refractometer to measure salinity of our oceans.

• Six ions make up ~99% of the salts dissolved the ocean with Na and Cl

making up 85%

• Seawater generally has a conc of 35 parts / 1000 . now it preferred to

use practical salinity units (PSUs)

• Borate: without low concs, a lot of things can’t survive – this is in trace

concentrations.

• Nitrates + phosphates are under “other dissolved material” – this shows

in oceans they are very low; but the higher coloured patches of

Chlorophyll a: the higher concs are in the margins, as this is where the

run off from the rivers is.

Refractometer

6 of 114

Sea surface salinities of the world oceans (PSU = practical salinity unit)

Not a huge range in PSUS but there are higher concs (hotspots) in yellowed regions. At the poles there are lower salinities. Data from

the World Ocean Atlas 2009.

How do we measure this?

Heavy duty machinery is lowered down e.g. Rosette

of submersible water samplers with probes shown

here. There are collumns you can

detach from the core, and when you

send a messenger, it will trigger one

of them to close. This means that at a

certain depth you will trap water at intervals by operating a different

column each time à depth profile of the oceans. You can also get

temperature info etc.

This will enable you to produce figures: profiles

e.g. for phosphate in umol kg1.

Just be aware some areas are relatively high conc of phosphorous

and some relatively low

à you can see where the phosphorous, nitrate + silicon (needed

for diatrom custrles)

Radiolarans: heterotrophs also rely heavily on these substances.

Phosphate, Nitrate and Silicate (Fe is also important – a key enzyme; triggers enzymes to operate, facilitates their

activity + important in electron transport chains. )

Typical depth profiles of nutrients in the ocean

Picocyanobacteria are in oceans in huge concs. - this is the community

structure of pico.

From depth profiles you can get points of concs and get contour lines for

this type of depth profile: SRP = Soluble reactive phosphorus

– inorganic phosphate)

In the red sea in summer, low conc of phosphorous, difficult for new orgs

to thrive (K locked up in orgs)

Fuller et al. 2005; Limnol. Oceanogr., 50(1), 363–375Dynamics of

community structure and phosphate status of picocyanobacterial populations in the Gulf of Aqaba, Red Sea

- Genetic diversity + phosphate levels of Prochlorococcus and Synechococcus in red sea 1999-2000

- Used DNA probes and a P stress moleculer marker (PstS)

- High light adapted procho (HLII) dominated, low light adapted only present July – October and only in waters deeper

than 50m

- Highest PstS expression in both pops in summer à Organisms p stressed during summer months.

7 of 114 - Low expression in winter + string.

- Procho abdunace not affected by P stress, but Synechoccus may have been affected

by P stress, causing a decline in may 1999.

CTD (conductivity, temperature, density)

• period over the depth where temp doesn’t change: water mixed because all

same T

• as you continue to go down, there is a period where it rapidly drops, going

from 20- 4oc in 800m.

• similar things can happen in lakes (even shallow lakes but obvs over smaller

distances)

• Thermocline: a region where there is rapid drop in temperature.

Measuring profiles are good because they can help research of productivity: you

need to know how much carbon will get fixed in water to work out productivity.

Thermal inertial of water

Most ocean day-night temps vary by <1 oc.

Largest diurnal temp change follows continents.

- Carbon dioxide far more soluble in seawater than air – makes up 80% of dissolved

gas in water cf to 0.04% in air.

- There is between 0 and 8 ml l-1 of oxygen in seawater cf to 210 ml l-1 i.e. 21% oxygen in

air. – lower in water than in air.

- A plot of o2 would show that there are some regions where there is no oxygen = oxygen

min. zones.

- N2, Co2, O2

Two key processes strongly affect the amount of oxygen

(there is an OXYGEN MINIMUM ZONE- needs to be

replenished by ocean circulation

Oxygen circulation solves most problems with oxygen

minimum zone

Pressure

• Significant pressure changes with depth. As pressure

increases, the red balloon is compressed.

• Marine organisms may have air-filled bladders enabling

adjustment of their position in the water column.

Light Penetration in the Oceans

- Photosynthetically active radiation (PAR) 400 – 700 nm wavelength (mmol.

photons m-2 s-1)

- Secchi disc( – simple, painted areas of black / white, put on cable + lower it

into water column until disappears, used a lot in FW) , or submersible

‘photocells’ or quantum metres – needed in oceans: they measure wavelengths

of light / or just measure at the top + lower at intervals + get the attenuation of

light in the water column.

- Photocells with colour filters allow you to work out wavelengths: in oceans

blue light penetrates deeper than red. UV attenuated quickly, at low levels dissolved

organic carbon will stop it going which is good because this is dangerous

- In FW more green light.

8 of 114 - Turbidity (causes light to not penetrate: attenuate light

rapdidly) caused by e.g. phytoplankton or mineral particles

Light penetration in the sea

- Slopes provide the Extinction (attenuation) coefficient

- Light terminology: euphotic or photic is zone where there is enough

light for photosynthesis (more or less down to 1% of surface light).

- Disphotic or dysphotic zone has enough light for organisms to see and

aphotic does not.

- Water penetrates much further in clear oceanic than in turbid coastal

waters: in clearest oceanic waters, penetrates to over 1000m in

sunlight, but in coastal waters only to 200m.

- Penetration of the diff colours has an impact on what can be seen with

depth: At a depth of 30 m only blue light remains. Here the sea star

(Thromidia catalai) looks blue with black tips under natural light but an electronic flash

shows up the true colour

OPEN OCEAN PROFILES

• Salinity PROFILES variable due to rainfall, evaporation and river run off

• Surface layer (warm); intermediate layer (permanent thermocline) + Deep layer

(very cold but generally a constant temperature)

• Temperature and density are mirror images of each other

• In temperate and polar waters a ‘seasonal thermocline’ may develop: during the

summer there can be another thermocline that happens much higher up –

temporary thermocline causes layering of water in the upper layer – pink region.

– when you get a T gradient, hard to break it down (water lower down doesn’t

mix), orgs trapped in layers can run out of nutrients because of this lack of

nutrients)

• à So there are permanent + temporary thermoclines in oceans. à This affects

productivity in oceans

Seasonality in ocean depth profiles

In autumn, surface water cools, becoming denser + sinking =

DOWNWELLING

It displaces the deeper water which then rises. This process = OVERTURN

Surface mixed layer depth increase.

Ocean circulation from winds acting on the surface water

• Not evenly distributed: “roaring forties” etc

• At equator, air is warm, it rises + heads north and when it

gets colder it will sink again which affects the current on the oceans (which go

in all directions) just notice that there is doldrums where not much happening in way of

winds.

• Rising of sun warmed air and sinking of cold air leads to creation of major wind patterns

on earth.

Coriolis effect

Currents + winds are:

• Deflected to the right in the northern hemisphere

• Deflected to the left in S. hemisphere

9 of 114 Portuguese sailors in 15th C realsied you could ride these winds. IT causes Gyres ( large system of circulating ocean

currents, particularly those involved with large wind movements).

• When you have a surface current moving one way, it impacts

layer of water below it, deflecting that more and more to the right

(knock on), this means the net effect is that wind goes one way + water

goes 90oc to it.

• Each layer of water moves farther to the right as you head

down the water column with a net effect of water moving at right

angles to the wind direction overall. It is called an Ekman spiral

Major surface ocean currents in Indian, Pacific and Atlantic Oceans. The

large circular systems are called GYRES

wind away from the coast, surface water replenished from underneath à upwelling.

These oceanic gyres

affect the average

temperature at the

sea surface.

Tropical organisms (e.g. corals) found off west coasts and extend to higher latitudes whilst kelps (prefering cold

waters) occupy eastern shores of oceans

Ocean circulation

• The ocean is not stagnant – it circulates

• 90% of Deep circulation is caused by density differences in water masses.

• Water in extreme North and South Atlantic sinks and spreads along bottom and

to other ocean basins – this is how oxygen min. zones are replenished +

nutrients back to surface.

Wind-induced upwelling.

• Wind creates currents on surface of water:

Coriolis forces + Elkman spiral: water moves at 90o to

direction of wind .

• Areas of major upwelling: blue

arrows. – areas of upwelling critical to renewing nutrients at the surface which

have been depeleted by the phytoplankton.

• Upwelling brings up nutrients as water is blown away

• e.g. Peruvian upwelling + Californian

• gradation of productivity + coastal margins can be linked to figure below:

productivity higher at upwelling areas.

10 of 114 Important Recent Research:

A chain forming diatom in the oceans: pseudo-nitschia spp. It is a toxin producer.

McKibben et al. (2017) PNAS, 114, 239-244. Climatic regulation of the neurotoxin domoic

acid

• “Domoic acid is a potent neurotoxin produced by certain marine microalgae that can

accumulate in the foodweb, posing a health threat to human seafood consumers

and wildlife in coastal regions worldwide.”

• Elevations linked to warm phases of pacific devadal ossilation + oceanic nino index.

• Changes in currents + warm water currents being moved onto continental shelf are thought to contribute to ↑s In

the toxin.

• “findings reveal an association between domoic acid in shellfish and climate- scale warm ocean conditions, a

unique, large-scale perspective relative to previous work.|

• Common Rs between regions: “The warmer the ocean conditions, the more likely DA is to surpass alert thresholds

during upwelling season, and the more toxic and/or more widespread a DA event has the potential to become. “

• Risks: DA in shellfish.

• Warming of the oceans + persistence may mean these increasesccontinue to occur + become more frequent. à risk:

climate-scale regulation of shellfish DA.

Castro + Huber chapter 3

1. Many of the unique properties of water result from the hydrogen bonds that form between water molecules.

2. Substances can exist in three states or phases: solid, liquid, and gas (or vapor) Water is the only substance that

naturally occurs in all three phases on earth.

3. Water is capable of transporting large amounts of energy because of its high heat capacity

4. Water is called the universal solvent because it can dissolve so many things. Dissolved materials are known as

solutes

5. Salts are composed of oppositely charged particles called ions

6. The principle that the relative composition of seawater is always the same is called the rule of constant

proportions

a. Dittmar analysed seawater from challenger expedition + found that % of major ions in seawater

remained constant even though total amount of salt varied – chloride ion always 55.03%. à Rule of

constant proprtions states that the relative amounts of various ions in seawater are always the same

7. The density of seawater is determined by temperature and salinity.

8. Because other colors are absorbed more at shallow depths, blue light penetrates the deepest in the ocean.

9. Most of the time the ocean is stratified, or layered, according to the density of the water.

10. The Coriolis effect deflects all large-scale motions on the earth's surface.

11. The major surface currents form large circular systems called gyres.

12. Waves transport energy but not water.

13. The moon affects the tides more than any other celestial body. Tides also are influenced by location and bottom

features such as depth and the shape of the basin of the body of water.

Water stratification: when water masses with different properties - salinity (halocline), oxygenation (chemocline), density

(pycnocline), temperature (thermocline) - form layers that act as barriers to water mixing which could lead to anoxia or

euxinia.

Lecture 3 – primary productivity of the oceans

• two regions where ocean is highly coloured

• UK on left: reflection caused by algae which has caco3 skeleton which causes reflection –

proliferation of these cells

o Emiliania huxleyi (coccolithophorid): Coccoliths are highly reflective – can cause changes

in sea surface temperature

• dinoflagellates blooming: tend to have reddish pigments – high concs of cells dying the water

• Talking about 1m cells in 2ml of water all competing for nutrients etc

In the literature: productivity is described as gross or net.

Gross (net) primary productivity = amount of inorganic carbon (Co2) fixed into

organic compounds by autotrophs (- respiration by autotroph)

Gross is total, net is the bit that will be available to things higher up in the food chain

Pseudo-nitzschia spp.

Domoic acid

11 of 114

Global comparison of carbon fixation

• Top image measures phytoplankton production in mg of carbon / m2 / day. –

surface area measurement

• You can see there are some places where the production is five times greater

than others (red vs green). This ties in with the upwelling areas: high concs of

nutrients: the land produces lots of these nutrients + the run-off to the coastal

regions is where you’ll have the most impact.

• Although there is not much going on in blue areas, quantitatively there is a lot

of blue areas: they are doing carbon fixation over a vast area so there is still a

lot of C being fixed here.

Why are we concerned? – 2nd image: distribution of zooplankton (copepods,

crustaceans etc) which feed on phytoplankton in water column - 1o consumers of the carbon being fixed by the algae.

The zoo plankton tracks the phytoplankton: strong correlation between the two.

Sperm whales also track the areas where the zooplankton are. – we are concerned because it is all linked.

What is happening in different areas that we will study?

- Table shows differences in rates of 10 production in marine

environments

- Pelagic (open water): not much variation between diff oceans,

coastal waters a bit higher

- Central oceanic gyers (light blue on prev image): not many nutrients

at all

- Equatorial upwelling areas: higher due to the constant upwelling, and

coastal upwelling reach the highest rates of production.

- Benthic environments are quantitatively very important in terms of

productivity: in some areas (Americas) benthic more productive than pelagic.

- All this carbon fixation = good because draws CO2 out of atmosphere.

- Terrestrial environments: some are fairly productive but none as productive as the coral reefs or the salt marsh

areas.

- Heterogenous in terms of amount of C being fixed.

How do we know what’s doing the fixation?

Various tracking devices:

SPOTS: San Pedro Ocean time series Microbial of the University of Southern

California

CPR – Continuous Plankton Recorder in Plymouth UK

• Water is drawn through the mesh + it picks up the plankton; this material

has been preserved for decades: one of the longest records.

• You can combine this with physical +chemical data to get a real picture

12 of 114 Size categories of plankton in the oceans: phyto+ Zooplankton. (nets may have

missed lots of this)

In addition to the photosynthetic

prokaryotes, a number of major groups of

eukaryotic phytoplankton grow to bloom

proportions in the sea.

Photosynthetic prokaryotes

• Lot of prokaryotes e.g. The cyanobacterium Trichodesmium : large aggregations: forms what looks like straw on the surface when it blooms.

• Prochlorococcus: Most abundant

photosynthetic organism in the sea – crucial for survival

• Stromatolites growing in the Bahama Islands

• Cyanobacterial bloom seen from space

(Capone et al., 1997)

• Diatoms also important: silica containing: lots have elaborate

spines to join together in fillaments + aids flotation.

Dinoflagellates

A lot are heterotrophic, a lot are photosynthetic

Have elaborate cell walls

Two flagella: allows them to select position in the water column: Motility can be an

advantage if surface waters are nutrient depleted (can move to other areas)

The dinoflagellate Gonyaulax polyedra – bioluminescent and forms red

tides

• Research provides decide of vertical migration in dinoflagellates: Doblin

et al. (2006). Harmful algae 5, 655- 677

• The figure shows salinity, temperature and fluorescence profiles from

the Huon Estuary, Tasmania, Australia, during 1–5 January 1998, showing

diel vertical migration of the phytoplankton (dominated by Gymnodinium catenatum) over the 20 m depth

of the water column. White and dark bars show periods of day and night.

A silicoflagellate skeleton : Dictyocha speculum - Blooms of these can block

understorey marine plants

Coccolithophores

• Coccoliths are made of calcium carbonate as an exo-skeleton. Contradictory evidence

surrounds the debate about impacts of ocean acidification on this group of algae

• Beare D, McQuatters-Gollop A, van der Hammen T, Machiels M, Teoh SJ, et al. (2013) Long-

Term Trends in Calcifying Plankton and pH in the North Sea. PLoS ONE 8(5): e61175.

doi:10.1371/journal.pone.0061175

o “Long-term trends show that abundances of foraminiferans, coccolithophores, and

echinoderm larvae have risen over the last few decades while the abundances of

bivalves and pteropods have declined.”

o pH declining since 1990s but no statistical connection between abundance f the calcifying plankton and

the pH trends. -any effects may be masked by temperature / nutrient concs.

o “Certain calcified plankton (like foraminiferans, coccolithophores, and echinoderm larvae) have

proliferated in the central North Sea, and are tolerant of changes in pH that have occurred since the

1950s but bivalve larvae and pteropods have declined. An improved monitoring programme is required

as ocean acidification may be occurring at a rate that will exceed the environmental niches of numerous

planktonic taxa, testing their capacities for acclimation and genetic adaptation.”

Hot spots of Trichodesmium

13 of 114

• Interspecific and intraspecific variation in coccolith density and size of

coccoliths

• Changes in the ability of these species to make coccoliths may have

important consequences on a global scale as they are key primary producers in

some places

Cyanobacterium trichodesmium: Prochlorococcus: most abundant photosynthetic

Three important groups are: Diatoms, Dinoflagellates, Coccolithophorids

Compared to terrestrial ‘green planet’

• Extremely small biomass involved

• Rapid turnover: entire global pop of phytoplankton is

replaced every 2-6 days…

• Coccolithopores are highly reflective due to the

calcium carbonate skeleton

Collectively we can see the Coccoliths, dinoflagellates + diatoms that

are responsible for most of the production in different regions: there

are more or less of them depending on where you are.

More Coccoliths + dinof in tropical regions, but in poles: more

diatoms.

Various stressors have impact on species selection in different regions

Seasonal patterns of primary productivity in different lattitudes - why different mounts of production: nutrients, light ,

temperature, mixing

- Green areas show primary productivity – rate of p/s over whole year

- Tropics: same as whole time in tropics but little oscillations; Species change in the tropics but hardly ever reach excessive blooms as we do in temperarate + polar waters

- Temperate: early part of the year: light limited as not much solar radiation

penetrating

o As increases, massive increases in primary productivity + big peak – we

call this the spring bloom

o Spring bloom kicks off whole food web st beginning of year

o Will go down because 1. Zooplankton consumes them 2. Nutrients get

depleted (e.g. silica) – summer stratification will mean that the diatoms

producing the bloom are confined in the layer + layers don’t mix due to

density differences so can’t get nutrients from the other layers – can

only get more nutrients from faecal depositis from zooplankton that

has fed on phytoplankton - there is some nutrient recycling. This leads

to a summer lull, relatively low conc.

o might get a “fall bloom” – always lower than spring, happens again due

to the surface temp dropping until eventually it is similar to layers below

it à down- welling (mixes with waters underneath + brings up more

nutrients) this is enough to trigger a small bloom).

- Polar: light limiting for much of the year until late spring: boom (could be bigger than in temperate waters), but only a

narrow window of opportunity (6-8 weeks) where they start to decrease: temp drops + it

gets dark. – they can still be v. productive while they are there

Unique life option!: Sea ice algae: mostly diatoms that live in bring channels.