Artist:Glynn Gorick

1
ArtistGlynn Gorick
Biological production in the sea - the physical
and chemical basis
Keith Brander ICES/GLOBEC
2
Spring chlorophyll (1998-2003 seen from space by
SeaWifs)
3
(No Transcript)
4
(No Transcript)
5
Surface currents
6
(No Transcript)
7
Digression on herring migration
from Vilhjalmsson 1997
8
Vertical and horizontal mixing
9
The Carta Marina was published in 1539. It was
made by cartographer Olaus Magnus, an exiled
Swedish priest living in Italy. The map took 12
years to complete and is one of the first to give
Finland and parts of Russia roughly correct
proportions.
10
(No Transcript)
11
ArtistGlynn Gorick
How does biological production in the sea take
place?
12
The Prologue - Marine Food Chain
13
(No Transcript)
14
Photosynthesis a chemical reaction performed by
plants which use chlorophyll or carotenoids-
light absorbing pigments.

• It requires
• energy from sunlight (only in the near surface
  layer)
• nutrients (nitrate, phosphate, silicate, trace
  elements)
• (water - not a problem in the sea)
• It converts light energy to chemical energy and
  produces carbohydrates (organic matter, glucose)

15
(No Transcript)
16
Primary productivity the amount of carbon
incorporated into organic matter by autotrophs
per square meter of ocean surface per year
gC.m-2.y-1 Production Sea Land Average 140
gC.m-2.y-1 400 gC.m-2.y-1 Total 52
GtC.y-1 60 GtC.y-1 Total biomass 1.5
GtC 800 GtC Marine primary producers are much
more efficient Marine production is limited by
light, nutrients (mainly nitrate) and grazing
17
Digression on global change What will the
effects of increased human-induced nitrogen flux
be?
18
Uptake of CO2 in the sea is vital to global
carbon cycle
19
Where does the carbon go?
It also runs your car
20
What else do phytoplankton do?
21
5 mm
Who eats phytoplankton?
Calanus finmarchicus
which is a copepod
22
NORTH ATLANTIC OCEAN
SHELF SEAS
Climate forcing of ocean circulation
23
ArtistGlynn Gorick
24
(No Transcript)
25
(No Transcript)
26
5th level
1st level
4th level
3rd level
2nd level
27
Transfer through the trophic pyramid
28

• What are the differences between terrestrial and
  marine harvest?
• On land we farm plant crops and herbivores
• In the sea we harvest high level carnivores.
  Marine plants are too small and low in biomass.
• On land we control breeding and varieties we
  feed or fertilise, we control weeds and predators
• Fisheries are based on wild populations, which
  fluctuate unpredictably as conditions change
• We dont have direct experience of life in the
  sea

29
Digression on North Sea cod and plankton

• For nerds
• Monthly values of the first PC (33.78 of the
  total variability).
• Main variables by order of importance
• mean abundance of C. finmarchicus
• mean abundance of euphausiids
• mean size of calanoid copepod
• mean abundance of C. helgolandicus
• calanoid copepod biomass
• mean abundance of Pseudocalanus spp.

Months
Years (1958-1999)
This does not mean that changes in plankton are
the only cause of decline in cod
30
What about the effects of climate change?
31
North Pole.
Last glacial maximum.
Present day.
sea ice
sea ice
Source Climap project.
32
Southern shelf edge species
Changes in range of copepod speciesfrom
Beaugrand et al. 2002 Science in press. Based on
176,778 CPR samples.
Psuedo-oceanic temperate species
Euchaeta gracilis, Euchaeta hebes, Ctenocalanus
vanus, Calanoides carinatus
Rhincalanus nasutus, Eucalanus crassus,
Centropages typicus, Candacia armata, C.
helgolandicus
33
Jean-Claude Quero Ital.J.Zool.,65 Suppl.493-499
(1998)
34
people are interested in changes in marine
ecosystems.
35
Ratio of catch of warm/cold species
36
Ratio of catch of warm/cold species
37
What consequences can we expect from warming
climate? Changes in distribution of plankton
and fish are already occurring Changes in
biodiversity (is this good or bad?) Problems for
fish farms (which may have to switch to warm
adapted species) Possible changes in plankton
production (due reduced vertical mixing) Invasive
species e.g. from the Pacific
38

• Final thoughts
• Marine and coastal ecosystems provide many
  ecological services
• Some of these (nutrient cycling, flood and
  coastal defence, waste disposal, water
  purification, tourism) are very valuable
• Other uses have consequences for fisheries
• Production in the sea may change as a result of
  nutrient input and other global change effects
• Fisheries are part of the marine ecosystem, with
  effects in both directions

39
What was this talk about?
Blowed if I know