Biofilter in-situ incubation

Ken CollinsSouthampton Oceanography Centre

Sampling pump

mixing pump

Oxygen electrode

Control – seawater only

Biofilter + seawater

Pump batteries

Winkler bottle

Oxygen meter

Biofilter incubation 25.4.02

time mins

0 20 40 60 80 100 120 140 160 180 200

Oxy

gen

conc

entr

atio

n m

ol l-1

100

120

140

160

180

200

220

240

260

280

300

chamber Winkler chamber regressioncontrol Winklercontrol regression

O2 = 276.4 - 0.728 * mins

r2 = 0.97

faunal community respiration rates

Temperature oC

4 6 8 10 12 14 16 18 20 22

oxy

gen

con

sum

ptio

n

mo

lO2 g

AF

DW

-1 h

-1

0

10

20

30

40

50

60

s

s

s

o

o

o

r

rrr r

r r

r

s - Southamptono - Obanr - artificial reef

Slovenia +

Soton & Oban biofilter incubations

group

ascidians barnacles crustacea hydroids molluscs worms

prop

ort

ion

AF

DW

0.0

0.2

0.4

0.6

0.8

1.0

28.3.0225.4.0216.9.0217.9.0218.9.02

Temperature effect Q10

ln Q10 = [10/(T2-T1)] ln k2/k1

if Q10 = 2,, T2 = 20oC, T1= 15oC

ln 2 = [10/(20-15)] ln k20/k15

.693 = 2 ln k20/k15

k20= 1.414 k15

faunal community respiration ratesnormalised to 20oC using Q10 = 2.0

incubation temperature oC

8 10 12 14 16 18 20 22

oxy

gen

co

nsu

mp

tion

m

olO

2 gA

FD

W-1

h-1

20

30

40

50

60

70

80

90

100

s

s

o

o

o

r

r

rr

r

rr

r

s - Southamptono - Obanr - artificial reef

Slovenia +

Average respiration rate at 20oC

= 53 +/_ 16 umolO2 gAFDW-1 h-1

oxygen consumption- carbon flux (1mole O2 = 1mole C)- nutrient flux (Redfield ratio

C:N:P=106:16:1)- filtration rate