L8 Chemical Pollution Part1 Aquatic/Food link/Recovery

Question 1

Why care about pollution?

• Planetary boundaries link
• give 8 examples
• importace

Answer 1

Multiple planetary boundaries are tied to chemical change

1) Climate (350ppm) Co2
2) Atmospheric pollution (health standards)
3) Nitrogen - 25% of current human-driven flow
4) Ocean acidity (carbon saturation) 5)Freshwater <500km3/yr 6)Marine biosphere (ecosystem services)
7) Agricultural land use <35% of total land area
8) Chemicals (genetic and fertility impacts

Thus we need to indentify the local-global thresholds for tipping points for sustaining human civilisation

Question 2

9 planetary boundaries (note actually 10)

Answer 2

1	Climate change
2	Biodiversity loss
3	Nitrogen cycle
4	Phosphorus
.5	Ocean acidification
.6	Land use
.7	Freshwater
8	Ozone depletion
9	Atmospheric aerosols
10	Chemical pollution

Question 3

Nitrogen boundary detail

Answer 3

Nitrogen and phosphorous pollution
these are both essential for plant growth – BUT sfertilizer productin and application is a key concern – excess application ends up in non target habitats  leading to eutrophication

Question 4

chemical pollution boundary detail

quantification problem?

Answer 4

there are a range of chemical toxins – a sigle boundary cannot be quantified but the risk of crossing Earth Systems thresholds is significantly high for it to be a prioriy for precautionary action and research

Question 5

Freshwater and global hyrological cycleboundary  detail 
problem
double problem (food)

Answer 5

Linked to climate change and resource overexploiutation – shifts can be abrupt – boundary for consumptive freshwater use and environmental flow requirements has been proposed to maintain overall resilience of the earth system
Problem: Overabstraction also frgaments aquatic habitats and reduces their ability to dilute pollutants –

For example: Greening the desert to feed a growing human population – This type of farming uses huge volumes of water – overabstraction is lowering the water table and drying up rivers in many arid areas

Question 6

How will CC affect these boundaries?

• effect of drought link
• Ledger
• suprinsingly positive?

Answer 6

Drought supresses secondary production by ½ an order of magnitude : resilience is eroded

Ledger et al (Nature Climate Change, 2012)

possible positive?
Our research unearths previously unknown compensatory dynamics arising from within the core that could underpin food web stability in the face of environmental perturbations.

Question 7

Problem with going past boundaries?
Reversal?
Public Perceptions?
led on to global changes in aquatic systems over time

Answer 7

Removing the stressor may not reverse impacts especially if the ecosystem has been pushed into a new state by drought

as drought intensifies freshwater habitats are lost and terrestrial habitats are gained .. reversing these changes could be difficult as the terrestrial vegetation re-engineers the ecosystem

Different Public perceptions of Aquatic vs Terrestrial ecosystems:
• Often terrestrial ecosystems get more public outrage after pollution and protests ensue
• However – aquatic system often has no protest and people carry on going to the beach  ie problem with MPA –Australia shows bias of bad quality areas and some areas in aus don’t even contain threatened spp

How can we gauge the impacts of land use on aquatic ecosystems?

Many effects of lland use change seen in sea/ aquatic systems ie
a)increasing land yields via fertilisers b)Increasing yields via pesticides

Question 8

Overview

Answer 8

1. Planetary boundaries + detail
2. Boundary link with CC - drought and stressor removal
3. Global changes in aquatic systems over time
4. Multiple stressors (food link)
5. Stopping and effect of pollutants
6. Monitoring
7. Ecosystem function
8. Restoring

Question 9

3.Global chnages in aquatic systems over time?

dates and event (first 4)

Answer 9

• 1850-1875 Land clearance,industrial revolution. Sewage  mor eeutrophicaion /chemical pollution/habitat of rivers and estuaries and beginning of overfishing of coastal shelf
• 1875-1900 Steam trawlers and rail transport Larger effects in rivers and estuaries and major obverfishing in estuaries
• 1900-1925 Oil shipments and chemical Industry Start to see chemical pollution and habitat loss also in the coastal shelf and intensification
• 1925-1950 Radio communications, War and munitions dumping  Intensification of everything in coastal shelf and rivers in particular

Question 10

Globval changes in aquatic systems over time ?

dates and events (final 3)

Answer 10

• 1950-1975 Sewage treatment,nuclear power , Green revolution , Environment ministries  rivers se declines in eut/chem/habloss and same for estuaries BUT problem  coastal shelf habita and overfishing continues to worsen and now Deep sea is threatened by all 3 apart from eut
• 1975-2000 – Aquaculture, globalisation,deep water fishing, Enviro NGOs  Coastal chemical pollution decreases and River and estuaries better protected BUT Deep sea fishing intensifies overfishing and habitat loss masively
• 2000+ - Global warming,urban development and Coastal squeeze  see for rivers decreasing in all 3 , estuaries decrease ijcchemical pollution but an increase in habitat loss (coastal squeeze) and for Deep sea habitat loss is worse as is overfishing

Question 11

1850-1875

1875-1900

Answer 11

land clearance,industrial revolution. Sewage

Steam trawlers and rail transport

Question 12

1900-1925

1925-1950

Answer 12

1900-1925 Oil shipments and chemical Industry

1925-1950 Radio communications, War and munitions dumping`

Question 13

1950-1975

1975-2000

Answer 13

1950-1975 Sewage treatment,nuclear power , Green revolution ,
1975-2000 – Aquaculture, globalisation,deep water fishing, Enviro NGOs

Question 14

2000+

Answer 14

Global warming,urban development and Coastal squeeze

Question 15

4. Multiple Stressors
   link of freshwater? amazon example
   So what filters exert top down effect (5)

Answer 15

Freshwaters are aquatic islands in a terrestrial sea – what does this mean? It means that they are shaped by the surrounding ladn use at wider scales
• Again, the fact that land-use and water resources are intametey interlinked
• Even the vast amazon river is dominated by surrounding land

a) climate geology and water chemistry
2) hydrology and water chemistry
3) mutiple stressors (normally this wouldnt be exerting pressure)
4) biological inventory
5) Ecosytem functions

Question 16

4.Wider - multiple stressors in coupled river floodplain ecosystems
amphibians
European catchment database
management approaches

Answer 16

EFFECTS OF STRESSORS?
• Most aquatic insects and pond-breeding amphibians have complex life cycles with aquatic and terrestrial stages.
They are exposed to different stressors in their aquatic and terrestrial realm. Because most life history functions of aquatic insects are restricted to a short terrestrial period, we need to fully integrate the ‘airscape’ into the future management of river–floodplain ecosystems. Riverine floodplains integrate and accumulate multiple stressors at the catchment level, as reflected by distinct catchment fingerprints.

• Based on the European Catchment Data Base we provide spatially explicit information on multiple stressors; a key prerequisite for setting priorities in conservation and management planning. Implication: the management of stressed river and floodplain ecosystems is a major challenge for the near future and water managers worldwide.

Management approaches need to be adaptive and embedded within a catchment-wide concept to cope with upcoming pressures originating from global change.

Question 17

Food link detail - water consumption facts

• how many l for kg of meat?
• persons daily intake?
• pop increase?
• FAO says agriculture contributes how much %

Answer 17

• The world is THIRSTY because it is HUNGRY
• 15K litres needed to make 1kg of meat and 1kg of wheat needs 1500l
• To produce enough food to satisfy a person’s daily needs takes about 3000l of water
• Watre is a renewable BUT finite resouyrce  population has been continuously growing ans less water to satisfy needs for living healthy lif  many activities depend on water – drinking/washing/eating
• Agriculture and water - agriculture today accounts for 70% of total water use FAO water (domestic use v little)

Question 18

Stoppinng pollution?

• dilution but problem (denmark)?
• why restorastion often fails?

Answer 18

asnwer is dilution but problem
droughts and lack of water
Denmark floodplain 1871 - 1987 contrast 9arial satellite images

chemical pollution is key stressor
need to fix medium THEN matrix
water qual needs to improve for habitat qual to improve

Question 19

Effects of pollution?

general
agricultural footrpint
trends % increase in fertiliser consumption

Answer 19

loss of life ie fish deaths due to deoxygenation -Pollutants- toxins, acidification, nutrient enrichment and eutrophication

global fertiliser use – surface run-off washes excess nutrients into aquatic ecosystems

• Trends: world fertilizer consumption is increasing – 1950-2013 and use is likely to surpass 200 m t in 2018 a 25% increase from 2008 (UN FAO 2015)

Question 20

Eutrophication detail
what?
scale?
Resceding?

Answer 20

Biotic response to excess nutrients and organic pollution from rural and urban land use – algal and cyanobacterial blooms
• SCALE : Catchment-to coatss impacts : eutrophication can occur over many scales ie coastal regions of meditteranean and nutrient enriched blackwaters off the coast of florida
• RECEDING? Niutirent enrichment (N,P) from fertilisers and sewage created widespread damage to ecosystems – ofte nover large scales but in many parts of the developed world problem is receding due to enviro legislation

Question 21

WhyEutrophication ? competing demands on land and water examples

• Black Sea + Subsidies
• not new

Answer 21

• the freshwater Black Sea has eutrophied under CAP agricultural intensification
• Driver : agricultural subsidies ie Bulgaria , Romania
Note: this is not new  freshwatres have history of spp loss and enviro degradation via agriculture and urbanisation –
The great stink of 1858- The Thames turned into anoxix sewer forcing Houses of Parliament to shut – this triggered introduction of environemnrtal legislation an biomonitoring

Question 22

6. Monitoring
   a) Intro
   - why not chemistry?
   - species used
   - how tolerances are useful?

Answer 22

Chemistry is often too unrealiable SO we use integrated Biosensors of environmental conditions and pollution
- The lower trophic levels form the basis of most biomonitoring schemes
Bioassessment and monitoring in freshaters (using invertebrates to assess state of freshwaers)
1. Fly larvae – many fly larvae breath atmosphere through a long brathing tube or are very effective at extracting oxygen from the water using haemoglobin
2. Stoneflies (Plecoptera) and Mayflies (Ephemeroptera) are very INTOLERANT of low oxygen
Biomonitoring has focussed on nutrient enrichment and organic pollution, how can we use the insects?
• These different tolerances to low oxygen can be used to tell us about common forms of water pollution (sewage and nutrient enrichment)

Question 23

6. Monitoring

b)What tools?
what model / when?

Answer 23

1960s Hynes model
“classic “ resonse to organic pollution
This shows upstream reference state – impact and recovery zone downstream
Clear chemical an biotic succession of changes
Note: implicit gradient of “niches” in response to environmental change
So this returns us again to ideas about resilience, thresholds and tipping points

Question 24

Hynes model wider

Answer 24

Wider: The development of stream ecology as an independent discipline is fairly recent (occurring mostly over the past 25 years) and is an outgrowth of various initiatives (described below) that began in the 1950s and 1960s. Hynes’ (1970) classic book The Ecology of Running Waters may be regarded as the first book on stream ecology

Question 25

6.Monitoring

c)Defining things getting worse
-red flags?
Example National
Example EU

Answer 25

• We can define “red flags” (ie loss of key indicator spp) to warn us when things are getting worse – equally we can measure improvement in ecological status

National Biomonitoring shcemes – grappling with nutrient enrichment and eutrophication
• UK 600 “RivPACS” reference stram sites – spp level invertebrate data
• 3 species give different indications ie 1)poor 2)good 3)pristine
Ecological recovery?
Ecological recovery is when there is a rising percentafe of river length of good or excellent quality
1. Data : can see based on General quality assessment GQA - basically shows river length (%)
2. Chemistry - higher in wales and plateau and in England lower river length but increasing
3. Biology – higher in Wales but decreased between 1995-2000 but is now increasing again , in England appears to be slowly increasing

Eu level? EU Water Framework Directive
2005 was a key date to meet “good ecological status” for ALL surface waters
Note: RBMP = River Basin Management Plan

Question 26

monitoring exaples
national
eu

Answer 26

National Biomonitoring shcemes – grappling with nutrient enrichment and eutrophication
• UK 600 “RivPACS” reference stram sites – spp level invertebrate data
• 3 species give different indications ie 1)poor 2)good 3)pristine

Eu level? EU Water Framework Directive
2005 was a key date to meet “good ecological status” for ALL surface waters

Question 27

7.Ecosystem Functioning impacts? overview (4)

Answer 27

theory
contingent effects
continental scale effects
community structure

Question 28

7.Ecosystem functioning theory?

shape of relationship?

Answer 28

Biodiversity impacts are well known now but what about ecosystem functioning for example detrital processing in streams

Theory: in theory higher productivity = more spp = faster process rates
• HOWEVER under extreme nutrients loadings sp are lost and process ratezs may be impares.. so we may expect some sort of hump shape relationship

Question 29

7.contingent effects?

Answer 29

contingent effects may result inspace-filling within a bounding envelope - nutrient limitation at low levels, toxic effects at high concentrations

Question 30

7,continental scale effects?

Answer 30

nutrient enrichment has pushed many ecosystems ouuutsid their normal bounds but note the situation is improving (legislation and policy)

Question 31

7 Wider - nutrient loading continental scales
problem?
method?
result?

Answer 31

Systematic quantitative assessment of functional ecosystem measures for river networks is lacking, at continental scales.

narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process–leaf-litter breakdown–in 100 streams across a greater than 1000-fold nutrient gradient

This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

Question 32

7. Community structure? (3)

Answer 32

• Community structure is linked to ecosystem functioning
• Decomposition rates follow a unimodal curve across a eutrophication gradient
• Rates are fastest where lare consumers (“shredders”) predominate

Question 33

8. Restoration

Answer 33

a) zone
b)ecosystem shifts?
c) biotic interactions
Positive feedback (2 examples)
d)Norfolk broads evidence

Question 34

8. Restoration

what iszone for restoration?

Answer 34

he gold disc represents the systems most likely to yield maximum returns on restoration measures – beyond this chemical constraints override habitat constraints - not point in earlier lecture : YOU NEED TO FIX HIGH LEVEL FILTERS FIRST
Note: Hysteresis is the dependence of the state of a system on its history.

Question 35

8. restoration

ecosystem shifts?
clue (fish mediators)

Answer 35

Food web effects can trigger profound ecosystem regime shifts in shallow lakes
Ie clear water state with plenty of rooted plants - (cascade mediated by fish )  Turbid statee, with phytoplankton blooms and loss of rooted plants

Question 36

8. Restoration

role of biotic interactions
2 example titles

Answer 36

Alterantive ecosystem states may exist despite IDENTICAL environmental conditions – mediated by food web effects

Positive feedbacks for the clearwater plant-dominated state

Positive feedbacks for the turbid phytoplankton state

Question 37

Positive feedbacks for the clearwater plant-dominated state EXLAIN

Answer 37

1. Refugia for zooplankton
2. Plants deplete nutrients in the water column
3. Reduced water movement
4. Roots structure sediment

Question 38

Positive feedbacks for the turbid phytoplankton state

Answer 38

1. No plants = no refugia for zooplankton
2. Stunted fish eat smaller prey (zooplankton)
3. Release nutrients from sediment
4. Increase water movement
5. Loose organic sediment

Question 39

What these feedbacks tell us? / back to fish example

Answer 39

So.. Trophic cascades in shallow lakes…the food web determines ecosystem functioning
Fish suppress grazers  grazers supress periphyton  periphyton suppress plants

Question 40

8d

Experimental proof

Answer 40

Norfolk broads
manipulating the food web alters whole ecosystem state - can see from aerial images no fish and fish present areas look vastly different
What is Biomediation?
we can return lakes in the “grey zone” (below)
of algal blooms under moderate impacts to a better condition,
simply by removing fish  effectively we can “push” the system to a more desirable state by manipulating the food web (Friberg et al 2011)

Question 41

wider

more detail on shallow lake role of fish biotic interactions on recovery

Answer 41

the factors governing the success of aquatic plants were surveyed in 17 plant-dominated shallow lakes in Norfolk (United Kingdom) that varied in nutrient concentration and fish biomass. In these lakes, plant biomass was negatively related to the density of periphyton. However, the density of periphyton on the plants was correlated with the density of grazing invertebrates, not nutrient concentration. In turn, the biomass of fish determined the density of invertebrates. This cascade from fish to periphyton via invertebrates appeared to be evident even though plant-dominated lakes are heterogeneous and complex. Under conditions of plant dominance, periphyton appeared to have a stronger influence on plant growth than phytoplankton. Our data support a model where, within the range of nutrients where alternative equilibria are possible, fish are the prime determinants of community structure in shallow lakes, through a cascading effect of predation on grazing invertebrates influencing the biomass of periphyton and hence, plants.

Question 42

how many lakes in Norfolk

Answer 42

17 plant dominated

Question 43

What did the study suggest (wider) in terms of fish andstochasticity

Answer 43

We suggest that the stochasticity required for alternative equilibria in shallow lake communities is often derived from the vagaries of fish colonization and reproduction.

Question 44

wider Friberg 2011restoring riparian systems
what did they find

problem gravel

fine sediment accumulation

Answer 44

The introduction of large woody debris, boulders and gravel were the most commonly used restoration measures, but the potential positive effects of such local habitat enhancement schemes were often likely to be swamped by larger-scale geomorphological and physico-chemical effects. Studies demonstrating long-term biological recovery due to habitat enhancement were notable by their absence. In contrast, weir removal can have clear beneficial effects, although biological recovery might lag behind for several years, as huge amounts of fine sediment may have accumulated upstream of the former barrier.