KEOPS planning meeting 2

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KEOPS planning meeting 2 3 March 2004,
Marseille Contribution from Royal NIOZ trace
metal/phytoplankton group Klaas Timmermans
(presenting) Marcel Veldhuis Corina
Brussaard Patrick Laan Loes Gerringa Hein de
Baar Focus on trace metals (iron) and
interactions with phytoplankton (diatoms) THIS
PRESENTATION I) Analytical chemistry II)
Phytoplankton / viruses
Royal Netherlands Institute for Sea Research,
Texel, The Netherlands You are free to use (parts
of) this presentation, but notify the presenting
author.
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• But first, why do we want to participate in KEOPS
  ???
• Research interest in
• Iron distribution (horizontal, vertical)
• speciation (redox, organic complexation)
• sources (sediment, dust)
• interaction with
• Phytoplankton (physiology, distribution)
  phytoplankton viruses
• Extension of Southern Ocean work, natural Fe
  enrichment.
• All of which should lead to better insight in Si,
  N, P cycles,
• the role of phytoplankton as forcing factors, and
  the interaction
• with climate change.

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I). ANALYTICAL CHEMISTRY (focus on
iron). DISTRIBUTION Surface sampling
(torpedo). Depth profiles upto 4000 m (winch
clean CTD frame GoFlos). SPECIATION Total
dissolved Fe, Fe3 , Fe2 FIA-CL Organic
complexation of Fe voltammetry SOURCES
IRONAGES project 2000 2003. WP 1 IRON from
below sediment as sources of Fe (Gulf of
Biscay). WP2 IRON form above Canary Basin
(dust)
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tubing to the ship
tube inlet
Surface sampling non-iron fish Trace metal
clean sampling Filtration Tube into clean
container
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The usual suspects inside the NIOZ clean
laboratory van
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Alternative for GoFlos on the wire NIOZ KLEY
FRANCE deep sea winch 7000m kevlar cable (16 mm)
with internal signal cables, proven to be CLEAN.
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NIOZ Epoxy-coated stainless steel frame 22 trace
metal clean sampling bottles NOEX or GloFlo.
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driver unit pneumatics
Air tubes link
GoFlo with rotating ball valves
NOEX expanding silicone closures
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Routine deep profiling with ultraclean CTD frame
and cable
GOFlo on CTD-frame
GOFlo on single wire
Courtesy Geraldine Sarthou, Stephane Blain,
Patrick Laan, Klaas Timmermans October 2003
cruise IRONAGES-3 off West Africa
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How can we be of additional value for the KEOPS
cruises ? (Analytical
chemistry) KEOPS OBJECTIVE 1. Mechanisms of
natural iron fertilisation c) Iron distribution
and speciation. low and high iron sites
transects iron clean sampling and
analysis. For surface sampling towed fish For
depth profiles KLEY FRANCE winch with CTD
rosette and GoFlos
or GoFlos mounted on Kevlar wire. Sample
treatment/analysis inside clean laboratory
van. Dissolved Fe organic complexation of Fe
(shipboard)
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II. Phytoplankton/viruses BIOGEOCHEMISTRY
studies at circulation of chemical elements in
the ocean, between ocean and atmosphere, as
governed by anabolic and catabolic activities of
living organisms. Primary producers are main
drivers of biogeochemical cycles of C, N, Si and
P. Main functional groups diatoms,
coccolithophorids, Phaeocystis ,
picophytoplankton. In HNLC areas, the large
diatoms show the stongest response to Fe
fertilisation and nutrient uptake is under
strong influence of availability of Fe.
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Specific research
questions. Phytoplankton physiology -
Co-limitation of diatoms by iron and silicate,
iron and light. - Elemental composition of
diatoms in relation to iron, silicate. - Size
differential effect of Fe fertilisation. -
Optimalisation of biogeochemical
models. Phytoplankton viruses - Role of
viruses in controlling small phytoplankton
species. - Role of viruses in nutrient
recycling.
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And in practice Phytoplankton distribution
abundance and species compostion of natural
assemblages. Phytoplankton physiology
growth/mortality, co-limitation, nutrient uptake
in relation to iron (and silicate and light) of
natural assemblages and single
species. Phytoplankton viruses abundance,
diversity and lysis rates.
Laboratory experiments with the bloom forming
diatom species Natural filtered Southern Ocean
water High Nutrient, Low Chlorophyl (HNLC)
waters, no additions other than iron (as FeCl3
or dust) What is the effect of iron on
µmax and Km ? nutrient (N, P, Si)
uptake (ratios) ?
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Klaas never travels alone... single species
cultures of large Southern Ocean diatoms)
Thalassiosira sp.
Actinocyclus sp.
80 µm
140 µm
80 µm
70 µm
Fragilariopsis kerguelensis
Chaetoceros dichaeta
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Growth rate (d-1)
Shipboard experiments
ambient dissolved Fe
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Km C.brevis 0.59 x 10-12 M
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Km C.dichaeta 1.12 x 10-9 M
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In the Southern Ocean Large C. dichaeta is
mostly Fe-limited except after Fe supply. Small
C. brevis is never Fe-limited but
grazer-controlled (viruses ???).
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Timmermans et al. Limnol. Oceanogr, 2001.
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Growth rates versus Fediss Experiments in HNLC
Southern Ocean waters, nothing added but Fe
Fragilariopsis kerguelensis
Growth rate (d-1)
µmax Km (d-1) Fediss (nM) Actinocyclus
sp. 0.34 0.98 Thalassiosira sp. 0.31 0.62 C.
pennatum 0.36 0.57 F. kerguelensis 0.39 0.19
Fediss (nM)
Laboratory experiments
ambient Fediss 0.2 nM
Timmermans et al. Limnol Oceanogr. (almost
accepted)
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Si uptake increases under Fe limitation N
uptake decreases under Fe limitation P uptake
variable effects of Fe limitation
Nutrient uptake versus Fediss
Effect on molar uptake ratios
Molar uptake ratio
NP 16
Fragilariopsis kerguelensis
SiN 7.5
Actinocyclus sp.
NP 5.8
SiN 2
Laboratory experiments
Fediss (nM)
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Where does the iron come from, what is
bioavailable ? combined physico-chemical and
biological approach (diatoms as indicators of
availability of Fe originating from dust).
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Physico-chemical analyses of the dust DUST (only
fraction lt63 µm used) Namibia silty clay
loam Mauretania sand Characterisation 1)
Specific surface area 2) Mineral composition 3)
Fe Amorphous Fe Crystalline Fe Total
Fe 4) Dissolution of particles in seawater /
concentration of Fediss All indicating Namibia
gt Mauretania , BUT is there a link
with bioavailability of Fe from the dust ???
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if you cannot measure it chemically, let the
diatoms tell it !!
Growth rate (d-1)
Actinocyclus sp.
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Growth curve (FeCl3)
known amount of dust gives growth rate
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3
Fediss (nM)
bioavailable Fe from dust
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Growth responses
Additions 1 mg Maur., 5 mg Maur.,
1 mg Nam. 5 mg Nam. FeCL3
additions
dust addition growth rates increase Namibia gt
Mauretania
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Overall
RESULTS Addition Fediss (nM)
Actinocyclus sp. Thalassiosira sp. DUST
measured says
says 1 mg Namibia 12.8 gt 5.0 nM
(?) 0.12 nM (1) 5 mg Namibia 44.2 gt 5.0
nM (?) 0.32 nM (1) 1 mg Mauretania 1.7
0.50 nM (29) 0.04 nM (2) 5 mg Mauretania
5.8 0.36 nM (6) 0.04 nM (1)
CONCLUSION. Yes, dust is a source of
iron for the ocean, but only a (small) part of
the iron that dissolves from the dust is
bioavailable !!
Visser, Gerringa, van der Gaast, de Baar
andTimmermans (2003). J. Phycol.
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How can we be of additional value for the
KEOPS cruises ? (phytoplankton /
viruses) KEOPS OBJECTIVE 2.1 aerosols as source
of Fe to the ocean. Use of phytoplankton
(natural assemblages, single diatom species) as
bio-indicators of Fe originating from aerosol
dust. KEOPS OBJECTIVE 3. Factors regulating
phytoplankton growth and species composition,
structure of the phytoplankton communities,
etc. In situ Responses of phytoplankton
(diatoms) along KEOPS gradients and on low and
high iron sites. How ? Quantification and
probing of natural phytoplankton and virus
assemblages.
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Main approach for on board experiments
(OBEX) Culturing of and experimenting with
Antarctic phytoplankton in natural seawater, as
indicators of bioavailable iron (sediments or
dust), silicate and/or light. Viral induced
mortality of phytoplankton in low and high
iron sites. How ? Incubations with single
species SO diatoms (large small). OBEX
1. Incubations with natural (diatom)
phytoplankton population translocation
experiments from Fe-rich, Si-poor to Fe poor and
Si-rich waters (and vice versa). OBEX 1. Fe and
Si recycling due to physiological automortality,
virus mediated cell death or micro-zooplankton
grazing of the phytoplankton. OBEX 2 and 3.
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Parameters Growth and mortality of phytoplankton
(diatoms) Physiological automortality with
SYTOX viability assay. Next slide Silification
PDMPO probe (Marie Curie fellowship application ,
Karine Leblanc) Nutrient uptake ? nutrient uptake
ratios Photosynthetic efficiency (Fv/Fm) Virus
mediated cell death or micro-zooplankton
grazing EQUIPMENT. Flowcytometry 2 x Coulter
BD Pulse Amplitude Modulated fluorometer (PAM)
? Fv/Fm Microscopy Large Antarctic diatoms
Actinocyclus, Thalassiosira , Eucampia,
Proboscia. (more new fresh- requested from
EIFEX cruise) Small Antarctic diatoms Chaetocero
s brevis, Thalassiosira antarctica

!!!!! ALL TRACE METAL CLEAN !!!!!
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growth rate (d-1)
T. antarctica
Diatom automortality SILICATE SYTOX viability
probe for individual cells, quantified using
flowcytometry.
growth rate
Lysis rates increase with low silicate
concentrations.
lysis rate (d-1)
Si (µM)
lysis rate
Si (µM)
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Summarising for the KEOPS in situ OBEX 1 -
3 Water from low and high iron sites (and
varying silicate) light Natural phytoplankton
and single species responses of
growth nutrient uptake (ratios)
auto mortality viral induced
mortality silification
photosynthetic efficiency
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And additionally, proposal submitted for Real
time satellite imagery of SEAWIFFS
interpretation
?
Jan. 2005
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All of which should lead to better insight in Si,
N, P ( C) cycles, the role of phytoplankton as
forcing factors, and the interaction with
climate change.
At the end we hope to say still
confused, but now on a much higher level ...