Remineralisation rates of sinking particles k2
This presentation is the property of its rightful owner.
Sponsored Links
1 / 12

Remineralisation rates of sinking particles – K2 PowerPoint PPT Presentation


  • 69 Views
  • Uploaded on
  • Presentation posted in: General

Remineralisation rates of sinking particles – K2. MP Gall, PW Boyd (NIWA) & J Valdes (WHOI). On VERTIGO we adopted 3 approaches to examining particle Remineralisation / Respiration. ii) In situ remineralisation of settling particles. ii) In situ respiration chambers.

Download Presentation

Remineralisation rates of sinking particles – K2

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Remineralisation rates of sinking particles k2

Remineralisation rates of sinking particles – K2

MP Gall, PW Boyd (NIWA)

&J Valdes (WHOI)


Remineralisation rates of sinking particles k2

On VERTIGO we adopted 3 approaches to examining particle

Remineralisation / Respiration

ii) In situ remineralisation

of settling particles

ii) In situ respiration

chambers

  • Shipboard Microwinkler

  • Incubations and ETS

Successful

A failure

Data on ETS and bacterial

ecto-enzymes before end

of 2006

(HOT data indicate bact assim. effic. of 10% or less


Remineralisation rates of sinking particles k2

Methodology (i)

A rotating ball

design was

employed to

prevent

swimmers entering

the inner sanctum

Our cylinder was deployed

at 150 m depth along with

other CLAP and ball trap

cylinders

A DO sensor was deployed within the

‘inner sanctum’ of the sediment trap


Remineralisation rates of sinking particles k2

T=0

T=36 h

T=72 h

10 min

STOP

DISSOLVED OXYGEN AND TEMPERATURE

WAS MEASURED EVERY 10 MINUTES

Fill trap with

water from 200 m

NO PRESERVATIVES


Remineralisation rates of sinking particles k2

Particles collected on

upper surface of the ball

once it stopped turning


Remineralisation rates of sinking particles k2

  • The experiments

  • Three 72 h deployments

  • 3 additional experiments

  • After deployment 3 the trap was placed in a temp

  • Controlled lab at atmospheric pressure and the

  • Remineralisation signature was followed for a further 36 h

  • ii) The video nasty – acclimated Neocalanus spp.

  • Were added to the water overlying the ball valve (which

  • Was coated with settled particles). Their behaviour was

  • Filmed – both with the ball in a stationary and in rotating

  • State.

  • iii) A serial addition experiment was conducted with

  • Neocalanus spp. – using microwinkler flasks to estimate

  • Their respiration rates


Remineralisation rates of sinking particles k2

Turley (1993) DSR I “linear decrease in rates of

Leucine and thymidine incorporation with increasing

Pressure” at 200 atm rates were 1/3 to ½ of those at

1 atm


K2 234 th flux

K2 234 Th flux

In deployment 1

the 234 Th flux for the

36 h collection period

was around 600 dpm

m-2 d-1

Data courtesy of KEN BUESSELER


Remineralisation rates of sinking particles k2

OXYGEN CONSUMPTION DUE TO PARTICLE REMINERALISATION

6.1 umol L-1

over 36 h

Export flux (as O2) = 74.29 umol L-1

This equals 6.2/74.3 is 8% over 36 h


Remineralisation rates of sinking particles k2

HOWEVER……

We recovered 9 copepods

Neocalanus cristatus

from the inner sanctum at the end of

the deployment

We set up a video of these animals at ambient temperature

on the upper side of a ‘particle laden’ ball.

It was clearly evident that they could ride the

ball and access the innner sanctum


Remineralisation rates of sinking particles k2

A FURTHER TRAP DEPLOYMENTS YIELDED COMPARABLE

OXYGEN CONSUMPTION RATES – despite a marked decrease in

Surface PP, EP, but not in b


Remineralisation rates of sinking particles k2

WHAT DO THE DATA TELL US?

Export flux (expressed as O2) = 74.29 umol L-1 over 36 h

At 150 m

So remineralisation equals 6.2/74.3 i.e. 8% over 36 h

However, the particles that remineralised are a complex mixture of fast and slow

sinkers (<10 m to 400 m d-1)

Mixed layer 40 m

150 m

Fast sinkers

Could be

600 m deeper

If it was not intercepted and remineralized in our

trap


  • Login