Week 7- Anthropogenic Stressors in Marine Benthos

What do we say sometimes in literature rather than stressor

Pressure (preferred term)

What is a marine stressor /main one affecting marine benthos

Pollution, plastic, chemicals, litter

• Can get long term pressures or short term pressures

Are there stressors unrelated to anthropogenic

Yes, anything an organisms has to deal with either adapted/not adapted

Define a stressor

Physical chemical biological factor that requires some sort of compensatory response by affected organisms placing constraints in productivity/development of ecosystem

• Can be global, local, region

• Pulse or press

• Long/short term

Why do we care about stressors

Everything has been accelerated since 1950s

WHy do stressors matter

Went from sediments that didnt move much to 4d with organisms moving

• Due to recycling of water that came from water column that fertilised oceans and lead to life

What did Thomas Huxley say

Some fisheries inexhaustible and others are exhaustible

What did Frank Thomas Bullen say

Abyss can promise no commercial/scientific gain

• Said thid due to little ability to access

• Those that were curious had academic use rather than pracyocal

What did ICES do

Promote and encourage research

What are views based on

Whether it is of use to you

Whats an issue with pressures

Get used to it

What happened to fish industry in Florida

Improved technologically and mechanically and got bigger= More shrimp

Industry then became heavily regulated before too late

How big of a problem are different pressures

What you are comparing to, whats your reference site/control

• Problem don’t always have historic comparison/reference condition

What are shifting baselines

Each generation perceives the environment they grew up with as "normal," even if it has already been significantly degraded compared to earlier times

e.g. composition and size may change over time

What is the extent of human impact

Virtually nowhere globally unaffected by human activity

• Gets worse as climate change increases

e.g. pollution, habitat. destruction, climate change, species invasion, unsusytainable resource use

What is problem with trawling (bottom fishing)

Bycatch/indirect impacts

Coextinction (local extinction)

Sedimentation/resuspension of sediment

What is the problem with mineral extraction

Pacific - 20million sq miles of ocean concentrated with minerals want to extract

Atlantic nodules contain less ore as higher sedimentation rate

Diamond mining comes with an array of issues

Sediment structure changes during extraction

What is the problem with carbon sequestration (controversial)

Not to much effect when something is changed

Postive global, negative local

Temporary removal

What is the problem with radioactive waste

Most is secret

Lots of europe affected

Was legal up to london dumping convention 1963

What can happen to nuclear disasters

Can end up in deep ocean

Can have areas with high radioactive material

Organisms then bioturbated it into sediment

Within 3 months of chernobyl radioactive substances on deep sea floor

Can benthos take up radioactivity

Yes, depends on species and feeding mode

What is the problem with shipwrecks

Increasing ship numbers= increased ship loss

Most in depths, coasts, high seas

Not just ship that is the contaminant also the content

Name some other types of dumping at sea

Fine silica particels tend to floculate

Reactive organic material

Nitrogen compounds

Inorganic solutes

Bacteria and human pathogens

Industrial contaminants

What are some ways to dispose of contained sewage

Releasing at lower depth so doesn’t spread so far

Wrap in barrels and put in seafloor

Take barrels to certain depth then they will explode at seafloor

What is increasing in the ocean

Hypoxia and anoxia - increasing in developed areas

What are persistent organic pollutants

Something doesn’t degrade in seawater

Are all stressors negative

No e.g. offshore infrastructure, can lead to specae for a community that wouldn’t normally be able to survive there

What are the issues with cables and pipelines

Cables are easier to lay

At end of a cable life it just stays there

In high demand at the moment

Security risk

Very hot and have electromagnetic

What are the issues with underwater sounds as a stressor

Increasing ship traffic and noise

Noise disrupts organisms

Effects behaviour

Can be under continuous sound under water

Sound carries very far and overlaps

Can stop species from ventilating/moving

What is the issue with warming as a stressor

Light, temp, freshwater

More human exploitation north too

Not just physical but side effects

Lots of interactions

Physiological performance of an organism affected by a range of things

What can we look at

Artfiical events or causes

What is UV radiation like as a stressor

Due to how ice is melting

Have more clouds in sky

Quantity and quality of UV is changing

What is marine litter like as a stressor

Lots dumped directly or indirectly

Often big issue is what happens to it- e.g. what it breaks down to/ chnages into

What is the problem with plastic alternatives

Often again have negative impacts on ecsosystem

What is the issue with pharmaceuticals

Both legal and illegal

Ocean organism respond in same way

Cocktail of pharmaceuticals in sea

Caffeine is a particular issue

Illicit drugs also affect species behaviour esp in undeveloped/inner city areas

What is an impact chain/pressure pathway

Particular activit y/sector activity e.g. fishing industry

Then creates a pressure e.g. demand, sound etc.

Then impacts the system in certain ways e.g. habitat destruction

What can a single human activity generate

Several impacts

What can multiple human activities contribute to

Single stressor

What stressors act together

Fishing and cable laying may both destroy species

What human activity may have a positive affect on species activity

E.g. seagrass, marine protected areas