Week 11- Anthropogenic Climate Change

What has happened to the ne Atlantic zooplankton species assemblages

From continuous plankton recorder- assemblages identified by thermal preference

• sub arctic species early has distribution into top of North Sea into Atlantic then by 2000s they are absent from North Sea - pushed north

• Warm temperate species previously in bay of bus at south of uk over time extended distribution

How have zooplankton distribution changes

C. Finmarchicus- cold water species

C. Helgolandicus- warm water

Indicator species

Give another example showing change in species distribution

NE ATLANTIC

Changes to subtropical gyre

Areas of mixing has massively increased over time due to warmer temps and subtropical gyre has been squeezed

What are the copepod indicators in Maria island, Tasmania like

Two studies with combined data sets - clear warm water species got more prevalent

What else has been affected

Movement of non- native species

Where has the non native species increase in warmer areas been seen

Northern hemisphere temperature= mean sea and land surface temp

Warm and tropical alien spp. in e.Mediterranean

150% increase after 1988

Lots getting into e.Mediterranean from Red Sea

What has happened to species diversity

Mean calankid copepod diversity has increase towards north

Tropicilisation- as temp warms species in warmer water going north/south following temp band

Greater diversity in warmer conditions

What is the relationship between diversity and body size

Inverse relationship between buodivesity and mean copepod body size

Why is there an inverse relationship between biodiversity and body size

Metabolic rates and food availability

What is the effect of an inverse relationship between biodiversity and mean body size

Negative correlation beteeen biodiversity and c content

How does warming affect body

At different biological scales

Population: James’s rule- within populations with smaller body size are in warmer waters

Individual: temperature-size rule- individual body size gets smaller ad temp increases and they mature quicker/development

Population: bergmanns rule- warm regions inhabited by small sized spp.

What is the direct effect of temp on how it’s controlling body size

Temp size rule

• increased temp= decreased development and smaller final adult size

• Development rate>growth rate

• Adult stage reached before potential size reached

What is the indirect effect of temp on how it’s controlling body size

Food type and availability

• increased stratification

• Reduced nitrate= lower pp and smaller phytoplankton species

• Less phytoplankton biomass as food

Give an in field example of surface warming and copepod size

1950s study in Long Island sound USA

Overall sst increase 0.03 degrees from 1948 to 2012

Body length has also decreased between 50 and 100 ,microns

How has climate change changed phenology (seasonality) in NE Pacific

Linked with PDO

Late in cold -ve years

Early in warm +ve years

Where else can we see changed in phenology due to climate change

Central North Sea

Most taxa are appearing earlier

What have we seen in changes in abundance

Hard to tell

But have seen an increase in Meroplankton

What are regime shifts

Sudden, dramatics and long lasting shifts in ecosystem structure and function- persistent shift in structure/ dynamics of the system often involving a change in internal feedbacks of system

How is climate change affecting the global ocean

Warming , oh and carbonate , storms, sea level rise

What is edsisttem structure

All living organisms and non living living together to form self supporting system maintained through energy flow from pp at base to top predators

How do you get ecosystem function

Combination of biological network and ecosystem structure

What are marine communities

Biological networks in which success of species is linked directly or indiscreetly through biological interactions

What are regime shifts

Pressure e.g. climate change, overfishing

Then could get a linear change in ecosystem change

Non linear change with a threshold for non kinear change

Regime shift ; abrupt change in ecosystem health (threshold point)

Or

A gentle reduction and abrupt transition to an alternative stable state big jump

What are regime shifts in n hemisphere ecosystems like

Main diver is climate in all ecosystems

Other drivers are overfishing and eutrophication

Get a rapid reduction in middle 1997-1993 significant change in state- regime shift

How do regime shifts affect zooplankton

Bug shift in zooplankton species

Cold dynamic equilibrium - low calankid spp diversity more cold water

Warm dynamic equilibrium- high calanoid more warm water

flatfish recruitment better in warm low salinity water

Dish recruitment on ne us coincides with regimes in copepod abundance and size structure