Aquatische Sedimente und anthropogene Kontaminationen · Aquatische Sedimente und anthropogene...

Analyse und Bewertung von Ökosystemen:

Werner Brack, UFZ Leipzig

Aquatische Sedimente und anthropogene Kontaminationen

Contents

•Was sind Sedimente?•Sedimentflüsse und Speicherung•Sedimente als Lebensraum

Benthische Algengemeinschaften und ihre Funktion für Ökosystem und Sedimentstabilität (Christina Bielefeld, Roland Kayser)

Benthische Invertebraten – Anpassung an einen besonderen Lebensraum (Reiss Benjamin, Jan von Baumbach)

•Typische Sedimentschadstoffe•Sedimente als Langzeitgedächtnis des Gewässers

Geochronologie von anthropogenen Schadstoffen in mitteleuropäischen Flusssedimenten (Lucas Streib, Jörg Staffel)

•Sedimenteigenschaften und Schadstoffbindung•Verteilung im System Sediment/Wasser/Biota – Bioverfügbarkeit von organischen Stoffen

•Bioverfügbarkeit von Metallen•(Bio)-chemische Reaktionen in Sedimenten

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Contents

Schadstoffe in Sedimenten - Herkunft, Verhalten und Wirkung –Stoffbeispiele

PAHs – Individuelle Fingerabdrücke helfen bei der Identifizierung der Quellen der Sedimentbelastung (Arik Freese)PCBs – Akkumulation sedimentbürtiger POPs in aquatischen Nahrungsketten (Maria Schulze)TBT – Antifouling mit gravierenden Folgen für aquatische Ökosysteme (Anja Knäbel, Julika Kreling)Perfluorierte Tenside als weitverbreitete Kontaminanten aquatischer Ökosysteme. Was wissen wir über die Akkumulation in Sedimenten und Biota?(Tobias Göhl)

Analyse und Bewertung von SedimentenProbenahmetechniken für Sedimente, Porenwasser und Schwebstoffe (Andreas Müller)Chemische Analyse (Werner Brack)Ökotoxikologische Wirkungstestung zur Analyse und Bewertung von Sedimenten (Nadja Metzner/ Werner Brack)

Mi

ContentsAnalyse und Bewertung von Sedimenten

Bewertung von Gewässer- und Sedimentqualität auf der Basis der benthischen Invertebratengemeinschaften. A. Sauerstoffmangel und organ. Belastung (Stichwort Saprobie) (Jan von Baumbach)Bewertung von Gewässer- und Sedimentqualität auf der Basis der benthischen Invertebratengemeinschaften. B: toxische Belastung (Stichwort SPecies At Risk, SPEAR) (Klaus Swarowsky, Florian Burgis)Sediment-Triade zur Bestimmung der Sedimentqualität (Julian Monka, Christian Löb)

Sedimentqualitätskriterien

Sedimentqualitätskriterien auf der Basis von „Apparent Effects Thresholds“ und „Screening Level Concentrations” (Clarissa Kluth, Nadine Bioselle)Regressionsanalyse zur Vorhersage von Sedimenttoxizitäten und zur Ableitung von Sedimentqualitätskriterien (Rainer Schlund)

SedimentmanagementEinführung (Werner Brack)Regulatorischer Rahmen für das Sedimentmanagement (Andreas Marx, Hannes Gaschnig)Fallbeispiele Sedimentmanagement (Ribana Seliger, Nadine Derber)

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What are sediments ?

Sediment means different things to different people.

The public often refers to sediments as mud, dirt or sludge



For many managers and regulators sediments are synonymous with dredged material



Definition by the European Sediment Network (SedNet)

Sediment is suspended or deposited solids, of mineral as well as organic material, acting as a main component of a matrix which has been or is susceptible to being transported by water.


Suspended or deposited solids

Problem: Distinction between solids and material in solution

In water chemistry often 0.45 µm as arbitrarily defined limit for solids. Below: solution.

⇒Sediment is defined as material > 0.45 µm (filtration)clay: < 2 µm, silt < 63 µm, sand < 2mm

Colloids (range 0.001 – 1 µm) are frequently ignored but may be very relevant for contaminant transport.


K.U.Totsche (TU München)

mineral as well as organic material


Finer particles (clay to fine sand) usually transported and deposited as aggregates or flocculated material containing:

•mineral particles•organic material•water•air

Scanning electron microscope image of a sediment floc (Owens, 2008)

relative composition determines properties and behaviour

mineral as well as organic material


Flocs: formed within the water column by a variety of physical, chemical and biological means.

Aggregates: formed outside of the aquatic system

Fine sediments often wrongly considered as individual particles when addressing their transport.

However: Flocculation

•increases effective particle size by orders of magnitude•changes particle shape, density, porosity and composition•significantly alters sediment and contaminant transport


Droppo, 2001, Hydrol. Precess. 15, 1551-1564

Characteristics of mineral components influencing floc behaviour

What are sediments ?Characteristics of organic material influencing floc behaviour


What are sediments ?Characteristics of fibrils influencing floc behaviour



•Suspended sediments (flocs and aggregates) are in continuous interaction with its aquatic surroundings.•Exchange of building materials, energy, nutrients and chemicals for biological growth, chemical reactions and morphological development.•On the micro-scale sediment properties and behavior are not stable but continuously change

Sediment functions

•Global denudation cycle (erosion and sedimentation)•Global biogeochemical cycling (e.g. carbon)•Transfer of nutrients and contaminants to oceans•Important natural resource (e.g. fertile soils in floodplains)•Providing diverse sedimentary habitats allowing high levels of biodiversity (river and coastal ecosystems)

⇒ Provision of food (important link in aquatic food webs → fish yields depend heavily on sustained production of diverse benthic prey species)⇒Provision of clean drinking water (degradation of toxicants)

Sediment Fluxes and Storages

•Sediment transport in the river channel by flowing water.•However: Outside the channel important processes supplying sediment to the channel:

•wind erosion•mass movements like landslides and rockfalls•flowing glaciers•human activities….

⇒ close relationship of land use with sediment problems

http://foto.blick.ch/album/CID-u0003196-55/index-u0003196:55.html


•Most sediments transported during high discharge events caused by precipitation, snowmelt and water release from dams.

•landslides•channel bank collapse•mining and dredging activities

•Non-discharge related high sediment fluxes caused by


Typical concentrations of suspended sediments in rivers:essentially zero to > 10 g/L at peak transport conditions

Annual mobilization of sediments from the land by soil erosion by water processes: 50 – 75×109 t

Annual sediment transport to oceans at global scale about 15 – 20×109 t

Difference: storage in floodplains, lakes, ponds and reservoirs


Owens (2008)

Global distribution of sediment fluxes to the oceans


Sediment budget for Europe

Owens 2005 J Soils Sediments 5:201-212

Sediment Fluxes and StoragesAnthropogenic impact on sediment fluxes to the oceans

ratio

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sed

imen

t loa

d

Deforestation, changes in landuse

dams trapping sediment before reaching the oceans

Enormous mass flow affecting ecology and economy

Many contaminants associated to sedimentsmass flow of sediments ≡ mass flow of contaminants

Material Sources

Sediment Erosion from agricultural land, channel banks, urban road dust, geological mines, atmospheric deposition..

Metals Geology, mining, industry, sewage treatment, urban runoff

Nutrients Agricultural and urban runoff, wastewater + sewage treatment

Organic toxicants Agriculture, industry, sewage, landfills, urban runoff

Radionuclides Nuclear power industry, military, geology

Sources of sediment associated material (examples)


Enormous mass flow affecting ecology and economy

Analysis using conceptual modelsnatural fluxes (numbers) and anthropogenic fluxes (letters)

Owens 2005 J Soils Sediments 5:201-212


Economic relevance – the problem of dredged material

Example: The River Elbe and the Port of Hamburg

-Port of Hamburg as huge sediment trap for the River Elbe-For maintenance of shipping traffic dredging of annually 2 to 5 million m3 sediments

One of the first steam dredges in the Port of Hamburg in 1877

-1.4 Million m3

treated on land-Costs for the City of Hamburg 30 million Euro annually



-Sediments as a valuable natural product-High contents of nutrients⇒In former times use of dredged material for agriculture and land reclamation

-With industrialisation starting around 1900 many heavy and chemical industries settled in the Elbe basin-Sediments as a major carrier and sink for inorganic and organic pollutants⇒ Today costly treatment and disposal of dredged material


Contamination primarily associated with fine grains (silt and clay)⇒Pre-treatment by separation of grain sizes⇒Sand fraction can be used as construction material⇒Fine grains need to be disposed

Example: METHA Treatment Plant, Hamburg



Process flow sheet of the METHA Separation plant



Francop disposal site for contaminated silt from the Port of Hamburg



Sediments as aquatic habitats

Valuable ecosystem with highly differentiated microhabitates generated by physical, chemical and biological processes.

Numerous ecological niches and high biodiversity.

Covich et al. (1999) BioScience

Ecosystem goods and services: Benefits of ecosystems for sustaining human populations

Decreasing benthic biodiversity leads to increasing vulnerability!Low species redundancy in freshwater sediments ⇒ Extinction or expansion of individual species may result in dramatic alterations of critical ecosystem processes.


Species richness and community composition of benthic invertebrates has an important influence on functioning of whole aquatic ecosystems and thus their goods and services.

Important ecosystems services provided by sediment biota•Regulation of major biogeochemical cycles•Retention and delivery of nutrients to plants and algae•Control of sediment structure + stability (and erosion)•Bioremediation of wastes and pollutants•Provision of clean drinking water•Provision of food (shrimp, crayfish, mussel clam, flounder…)•Translocation of nutrients. particles, gases•Regulation of atmospheric trace gases (e.g. CO2, NOx) •Modification of climate change (carbon sequestration)•Regulation of animal and plant populations•Control of pests and pathogens•Contribution to landscape heterogeneity + stability•Vital component of habitats important for recreation

Small tooth flounder (Pseudorhombus jenynsii)



Ecological zones

•Any water in the sea not close to the bottom is in the pelagic zone (water column)•The benthic zone is the ecological region at the lowest level of a body of water (ocean, lake, river) including the sediment surface and some sub-surface layers.

•The hyporheic zone is a region beneath and lateral to a stream bed, where there is mixing of shallow groundwater and surface water.

Owens (2008)


Sediments provide habitats for :

microflora: bacteria, protozoa and microphytobenthos (algae, cyanobacteria) and

metazoa (meio- and macrobenthos including invertebrates and vertebrates)


Bacteria play the decisive role in the zonation of sediments

1 cm

10 c

mIn a sediment core with a cross-sectional area of 1 cm2 and a depth of 10 cm we have about

•4 × 1010 bacterial cells, •104 heterotrophic flagellates and amoebae, •some 108 phototrophic cells (diatomes, flagellates, cyanobacteria) and •1000-4000 ciliates

CiliateFenchel (1992) Functional Ecology 6: 499-507

http://de.wikipedia.org/w/index.php?title=Bild:Stylonychia.jpg&filetimestamp=20041111103137


Sediment zonation resulting from decomposition of organic matterAhlf et al. 2001

Microbial decomposition of organic matter determines zonation•Normally few mm of aerobic (oxygen containing) layer•Depth of aerobic layer as a result of:

•microbial activity (consuming oxygen)

•photosynthesis of microphytobenthos (producing oxygen•diffusion of oxygen from water column

CH2O + O2 → CO2 + H2OΔG0 = -475 kJ/mol [CH2O]

Sediments as aquatic habitatsBelow the aerobic layer:

1) Fermentationresulting in short chain acids and hydrogen.Example: butyric fermentationC6H12O6 → C3H7COOH + 2CO2 + 2H2

ΔG0 = -265kJ/mol2) Denitrification

•aerobic and facultative anaerobic bacteria•reduction of NO3

- to N2•e- (respective [H]) from degradation of organic matter or oxidation of H25 CH2O + 4NO3

- → N2 + 4HCO3- + CO2 + 3H2O

Mun

k (2

000)

Mik

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ie

ΔG0 = -448 kJ/mol [CH2O]


3) Reduction of MnO2 and Fe3+

CH2O + 3CO2 + H2O + 2MnO2 → 2Mn2+ + 4HCO3-

ΔG0 = -349 kJ/mol [CH2O]

CH2O + 7CO2 + 4Fe(OH)3 → 4Fe2+ + 8HCO3- + 7H2O

ΔG0 = -114 kJ/mol•Limitation by the availability of Fe3+. •Low solubility: ferryhydrite about 10-8 M; goethite, hematite about 10-13 M•amorphic Fe3+ most important for microbial reduction

Fixation of Shewanella on manganite cristals


4) Sulfate reduction2CH2O + SO4

2- → H2S + 2HCO3-, ΔG0 = -77 kJ/mol

Often dominating in marine environments ([SO4

2-] about 28 mMol) while NO3

-

concentration very low

Precipitation as pyrite FeS2:

Fe2+ + S0 + H2S → FeS2 + 2H+ biogenic pyrite

Alternative: Exploitation of H2 from fermentation:

4H2 + SO42- → H2S + 2H2O + 2OH-


If pyrite gets in contact to O2:Microbial oxidation e.g by Acidithiobacillus ferrooxidans

FeS2 + O2 + H2O + CO2 → Fe2O3 + H2SO4 + [CH2O]

Acidithiobacillus ferrooxidans (pH-optimum 1.3 – 4.5)

Formation of sulfuric acid !

Major problem in acidic mining lakes

Sediments as aquatic habitatsSulfur cycle


5) Methane productionUse of H2 and short chain acids from fermentation

CO2 + 4H2 → CH4 + 2H2O

CH3COOH → CH4 + CO2

Reduction of CO2

or disproportionation of short chain acids e.g. acetic acid

⇒ only close association of fermenting (acidogenic) and methanogenic bacteria results in methane production

Removal of H2 from fermentation by anaerobic respiration (NO3-,

MnO2, Fe3+, CO2)⇒Important for thermodynamically efficient fermentation⇒Syntrophy: One species lives of the product of another species


Definitions: An autotroph (from the Greek autos = self and trophe = nutrition) is an organism that produces complex organic compounds from simple inorganic compounds (CO2) using energy from light or inorganic chemical reactions autotrophic.

A heterotroph (Greek heterone = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development.

A lithotroph is an organism which uses an inorganic substrate (H2, H2O, H2S, NH3, Fe2+….) to obtain reducing equivalents for use in biosynthesis (e.g. carbon dioxide fixation) or energy conservation via aerobic or anaerobic respiration.

An organotroph is an organism that obtains hydrogen or electrons from organic substrates.

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nts


Examples: •Plants are photolithoautotrophs (Energy from photosynthesis, inorganic H2O for reducing equivalents and organic carbon from CO2.•Chemolithoautotrophic bacteria (Energy from respiration; H2S, S, NO2-, NH3, Fe2+… for reducing equivalents; organic carbon from CO2)

Chemotrophs are organisms that obtain energy by the oxidation of electron donating molecules in their environments.

Phototroph (Greek: photo = light, troph = nourishment) are organisms that gain energy by photosynthesisen

ergy

sou

rce


In marine sediments at aerobic-anaerobic boundary small layer of coexistence between reduced S-species and O2.⇒Oxidation of S2- by

chemolithoautotrophic (energy from respiration or fermentation, inorganic e- donor S2-) orphotolithoautotrophic (energy from photosynthesis) bacteria if light reaches anaerobic layer

Development of mats of the chemolithoautotrophic bacteria Beggiatoa depending on the unstable mixture of O2 and H2S.

Chemosensory behavior towards oxygen

Fenchel (1992)


Ideal vertical zonation is super-imposed by heterogeneity on different scales

⇒ High diversity of habitats

•Turbulence and waves stir sediments and mix oxygen, NO3- or SO4

2-

into the sediments ⇒ successional events: oxygen disappearance →NO3

- and SO42- depletion → methanogenesis

•Burrowing of invertebrates locally extend the oxic zone into the sediment•Uneven distribution of organic material (e.g. dead organism) ⇒anaerobic spots in aerobic environments


In general: Aerobic-anaerobic boundary layer is a zone of elevated bacterial production ⇒ basis of microbial food webs, maximum density of protozoa and highest biodiversity

Boundary layer with chemoautotrophic bacteria Beggiatoa (filaments) and Thiovulum (small white sperical cells, but also diatoms, flagellates, ciliates and a nematode (Fenchel (1992)

High variety of sizes and shapes of prey organisms result in a high diversity of raptorial flagellates and ciliates (protozoa)

Orientation of protozoa in the O2 gradient


Microphytobenthos•Key factor: light•short term light deficiency: heterotrophic metabolism•long term deficiency: formation of resting stages•Uptake (and release) of nutrients from water and sediments•Small oxic microhabitats•Food chain


Microphytobenthos

Algae growing on sediments:epipelic: motile species preferring muddy sedimentsepipsammic: attached to grains in sandy sediments

Microphytobenthos is frequently buried by wave action, animal disturbance and sedimentation⇒suddenly in anoxic and dark environment (photic zone 0.15 to 1.4 mm)

•epipelic algae tolerate this only for short terms → rapid movement towards sediment surface•epipsammic algae tolerate dark anoxic conditions for several days but cannot move rapidely

Euglenophyta


•Predominating primary producers in most river ecosystems•Basic food for many invertebrates (grazers)•Influence mobilization and immobilization of nutrients and toxicants•Stabilize sediments (e.g. by extracellular polymeric substances)•Serve as microhabitats for epiphytic organisms•Offer protection to smaller invertebrates

MicrophytobenthosFunctions:


Benthic invertebrates

Organisms that live on the bottom of a water body or in the sediment and have no backbone.

Range from microscopic (<10 µm) to > 50 cm

lobsterCyclopoide (Copepoda)

Oligochaete (Lumbriculus variegatus)



Snails (Gastropoda)(Lymnea stagnalis)

Mussels (Bivalvia) (Sphaerium corneum)

Tubifex

http://www.biopix.dk/Species.asp?Language=de&Searchtext=Sphaerium%20corneum&Category=Bloeddyr



Isopoda (Asellus aquaticus)

Amphipoda (Flohkrebse) (Gammarus pulex)

Diptera (Chironomus tetans) Odonata (Libellenlarven)

http://www.biopix.com/Species.asp?Searchtext=Gammarus%20pulex&Category=Arthropoda

Calopteryx virgo



Macroinvertebrates can be characterized by traits.

Typical biological traits include:•maximal size•life cycle duration•potential number of reproductive cycles per year•aquatic stages (egg, larvae, pupa, adult)•reproduction (ovoviviparity, isolated eggs, clutches…)•dissemination (passive or active, aquatic or aerial)•resistance forms (eggs, cocoons, cells against desiccation, dormancy, none)•respiration organs

Traits describe the physical characteristics, ecological niche, and functional role of species within ecosystems

Usseglio-Polatera (2000) Hydrobiologia 422/423:153-162


Typical biological traits include:

•locomotion (flier, surface swimmer, full water swimmer, crawler, burrower (epibenthic), interstitial (endobenthic), attached•food (fine sediments + microorganisms, detritus (size?), living macrophytes, dead animals, living micro- or macroinvertebrates, vertebrates•feeding habits:

•predators(feeding on other invertebrates, e.g. dragonflies)


•omnivores (generalist feeders on both dead and living organic matter, e.g. crayfish)

•deposit feeders or collectors consuming fine pieces of organic matter (e.g. caddisfly larvae, Köcherfliegenlarven)

•filter feeders (e.g. clams) •scraper/grazer feeding on biofilms (e.g. snails)

http://images.google.de/imgres?imgurl=http://www.cirrusimage.com/images/caddisfly_larva.jpg&imgrefurl=http://www.cirrusimage.com/Trichoptera_caddisfly.htm&h=244&w=480&sz=32&hl=de&start=3&um=1&tbnid=gdr66e_49RFg2M:&tbnh=66&tbnw=129&prev=/images%3Fq%3Dcaddisfly%2Blarvae%2Bphoto%26um%3D1%26hl%3Dde%26sa%3DX

http://images.google.de/imgres?imgurl=http://asymptotia.com/wp-images/2006/09/freshwater_clam.jpeg&imgrefurl=http://asymptotia.com/2006/09/20/flying-clams/&h=313&w=469&sz=30&hl=de&start=1&um=1&tbnid=pf3uQCWgdZMajM:&tbnh=85&tbnw=128&prev=/images%3Fq%3Dfreshwater%2Bclam%2Bphoto%26um%3D1%26hl%3Dde


•shredder (consume coarse organic matter such as leaves, e.g. sow bugs (here Asellus aquaticus)

•piercer (feed by piercing the tissue of other organisms, e.g. true bugs – hemiptera - Wanzen)


In addition to biological traits ecological traits:

•type of water (river channel, banks, ponds, marshes, temporary waters, lakes, groundwaters)•longitudinal distribution (from source to estuary)•altitude•biogeographic regions•substrates (boulders, gravel, sand, silt, mud, macrophytes, roots, detritus…)•current velocity•trophic level (oligotrophic, mesorophic, eutrophic)•salinity•temperature•saprobity (pollution with organic waste)•pH


Traits (rather than species) are increasingly used for ecological risk assessment

Generic descriptors across community types help to • aggregate community data at any spatial scale• extrapolate data across geographic regions• link ecological function to mechanisms of action of

different stressors


Role of benthic invertebrates in nutrient cycling and outflow

•Transformation of organic detritus from sediment storage into dissolved nutrients that can be used by plants and algae to enhance primary production

•Feeding on algae and zooplankton

•Mixing of sediments and generating local redox gradients influence microbial activity and release of gases (CO2, CH4, H2S, NH3, N2)

•Consumption by fish

Covich et al. 1999


Burrowing and tube-building by deposit-feeding benthic invertebrates (bioturbators) helps to mix the sediment and enhances aerobic decomposition of organic matter.

Benthic invertebrates adapt to low oxygen environments in different ways: 1) by changing their environment

http://www.ozcoasts.org.au/glossary/def_c-d.jsp#decomp

http://www.ozcoasts.org.au/indicators/sediment_org_matter.jsp


Benthic invertebrates adapt to low oxygen environments in different ways: 2) by morphological adaptation

Example: Tubifex is feeding on organic matter in anaerobic sediments.For respiration they have a specific hollow in their end-tail containing the gills. They continuously wave this tail-end to catch oxygen from higher water levels. The less oxygen is in the water, the more they wave.


Benthic invertebrates adapt to low oxygen environments in different ways: 3) by physiological adaptation to low oxygen availability

Benthic invertebrates in low oxygen environments often have high hemoglobin concentrations for optimal exploitation of low oxygen contents.


What may affect benthic invertebrate communities and related goods and services?

•Changes in physical parameters (substrate composition, water temperature, depth, dissolved oxygen concentrations, pH, salinity, sediment C/N ratios and hydrography (stream beds, flows, waves…))•Nutrient enrichment leading to eutrophication (Stimulation by better food supply e.g. in form of organic detritus, drop of oxygen levels and anoxia)•Toxins produced by algae•Organic toxicants and heavy metals•Dredging activities•Introduction of pests and invasive species

⇒ Extinction or expansion of individual species (changes in community) may result in dramatic alterations of critical ecosystem processes.



Example 1:Recovery of Lake Erie’s dissolved oxygen contents

⇒Return of burrowing mayflies after elimination in the 1950s by eutrophication and pollution.

larvae of Hexagenia limbata

Hexagenia limbata

http://en.wikipedia.org/wiki/Image:Great_Lakes_Lake_Erie.png

http://www.freep.com/apps/pbcs.dll/section?template=zoom&Site=C4&Date=20080619&Category=SPORTS10&ArtNo=806190402&Ref=AR&Profile=1058


⇒ Nutrients are again rapidly converted from long-term storage in lake sediments into prey that are available to fish rather than accumulation in the muds.

Modeling of return of mayflies (Hexagenia limbata in competition to Chironomus)

Based on population growth of Hexagenia and Chironomusaccording to a sigmoid growth curve:

Nt+1 = Nt + (rN - rN2/K) N = initial density

r = population growth rate K=carrying capacity (=maximum density)

Consideration of low oxygen effects, predation by fish and sediment toxicity (-) and immigration (+)


Kolar et al. 1997 Ecological Applications 7:665-676


Results:•without additional stressor recovery after 10 – 41 years (a)•immigration reduces recolonization time by 2-17a•one low-oxygen event enhances by 5-17 a•contaminated sediments added 5-11 a•competition with Chironomusadded 8-19 a•fish predation added 4-47 a

Full model with lower carrying capacity (upper) and higher carrying capacity (lower figure)

⇒ after about 50 years full recovery may be expected

Kolar et al. 1997 Ecological Applications 7:665-676


Example 2: Expansion of (highly pollution tolerant) tubifexin sediments may result in a severe decline of fish populations.

Tubifex serves as a transmitter of the myxozoan fish parasite Myxobolus cerebraliscausing the whirling disease.

triactionmyxon (TAM) stage spore of Myxobolus cerebralis

http://en.wikipedia.org/wiki/Image:Fdl17-9-grey.jpg

http://upload.wikimedia.org/wikipedia/commons/b/b5/Actinomyxon.png

Illustration by Randy Bright Provided by Montana Fish, Wildlife, and Parks


Orconectes virilis Orconectes rusticus

Replacement of Orconectes virilis by the more aggressive Oroconectes rusticus in Wisconsin lakes (invasive species)

⇒Removal of macrophyte beds ⇒Loss of protective cover for fish larvae ⇒Decline of recruitment of juvenile fish

⇒ Break down of fisheriesCovich et al. 1999 BioScience 49:119-127

Example 3:


http://animaldiversity.ummz.umich.edu/site/resources/dale_westaby/Ovirilis3.jpg/view.html

http://animaldiversity.ummz.umich.edu/site/resources/dale_westaby/Orusticus1.jpg/view.html

Is there any evidence that toxicants may affect benthic ecosystem goods and services?

-Experiment: Dosing the insectice methoxychlor in a small stream

- Observing -community changes-leaf litter decomposition -seston concentrations (plankton, suspended matter)

Example 4:


ClCl

Cl

OO

CH3CH3

Exposure

Wallace et al. 1989. Hydrobiologia 179:135-147

96h LC50 for most insects about 1 µg/L

seasonal dosing


EPT: Ephemeroptera+Plecoptera+Trichoptera(Eintagsfliegen, Steinfliegen, Köcherfliegen, sensitive species, shredders)

Ephemeroptera

Wallace et al. 1996 Ecol. Appl. 6:140-151

Effect on biodiversity


Red Maple (Acer rubrum)

Significant reduction of leaf litter decomposition (doubling of time till 95% decompose)

Wallace et al. 1996 Ecol. Appl. 6:140-151


Is there any evidence that pesticides in environmental concentrations may affect benthic ecosystem goods and services?

-Study on effects of pesticides on community structure and ecosystem functions in France and Germany-Monitoring -Contamination (Toxic units)

-Species composition (SPEAR)-Leaf litter breakdown

Schäfer et al. 2007 Sci. Tot. Environ. 382:272-285

Exposure of air-dried Alnus glutinosa leafs in nylon bags

Example 5:


-Contamination (Toxic units)

-Approach to translate contaminant concentrations to toxic hazards-Normalisation of concentrations of specific compounds on effect concentrations to Daphnia magna (EC50) ⇒ individual TUs

-Maximum TU or Summation of individual TUs ⇒ estimate of total hazards

50

logEC

CTU =


-Species composition (SPEAR)

relative Sensitivity S -2.0 -1.5 -1.0 -0.5 0.0 0.5

1

10

30

5070

90

99

Per

cent

Ran

k

KrebsePlattwürmerRingelwürmerMollusken

n = 92 Taxa

Daphnia magna

species at risk

tolerant species

Basis: Species sensitivity distribution ⇒ division in two classes:

*P.C. von der Ohe, Liess M. 2004. Environ Toxicol Chem 23: 150-156.


-Species composition (SPEAR)

Example: Reference conditions


-Species composition (SPEAR)Example: Polluted site


Contamination (TUs) and species composition (SPEAR)



Correlation leaf litter decomposi-tion and SPEAR

In agricultural areas with high pesticide application benthic ecosystems services are affected!




Benthische Algengemeinschaften und ihre Funktion für Ökosystem und Sedimentstabilität

Christina Bielefeld, Roland Kayser

Benthische Invertebraten – Anpassung an einen besonderen Lebensraum

Reiss Benjamin, Jan von Baumbach

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