From fb1d3e615e609141a37b07000bebed5085fb4479 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?S=C3=B6ren=20Thomsen?= <32633545+soerenthomsen@users.noreply.github.com> Date: Mon, 11 Oct 2021 10:31:48 +0200 Subject: [PATCH] reformulation in pre-deployment operations and calibrations (#111) * reformulation * new formulation After Pierre's comment in #92 I tried to improve the formulation. --- sections/oxygen_pre_deployment.md | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/sections/oxygen_pre_deployment.md b/sections/oxygen_pre_deployment.md index 7e17d896..d2fb554b 100644 --- a/sections/oxygen_pre_deployment.md +++ b/sections/oxygen_pre_deployment.md @@ -17,7 +17,7 @@ The sensor then needs to be placed in water to hydrate at least 24 h prior to st Keeping sensor in small beakers before and during calibration process. Only the membrane will need to be submerged in distilled water. ::: -After recovery the sensor and to remove any biofouling, the following protocol is recommended by the manufacturer: +After recovery the sensor has to be cleaned to remove any biofouling. The following protocol is recommended by the manufacturer: 1. If the sensor has been for too long exposed to the air, leave it overnight in a vinegar solution. 2. Next day, place the sensor in soapy water and use a brush gently if it is necessary to remove all material adhered to the surface. 3. Rinse very well with clean water and dry carefully. @@ -147,9 +147,9 @@ Setup for 100% and 0% calibration. Issues with Winkler method at low oxygen concentrations (below 1 $\mu$mol/kg, some researchers consider that values below 20 $\mu$mol/kg shouldn't be use for the sensor calibration): - There are various issues with Winkler at low oxygen concentrations as Winkler always biases towards too high oxygen: the detection limit of the method is around 1 uM {cite}`Langdon2010`, the oxygen absorbed in the plastic of the Niskin bottles might be transferred to the water sampled (reference needed). -- For example, within the core of the Peruvian oxygen minimum zones oxygen concentrations at nmol levels are present -other approaches for 0 % in-situ calibration {cite}`Revsbech2009` and {cite}`Thomsen2016`. -- STOX sensor, new low-oxygen sensing foils (0-10% saturation) from Aanderaa. +- For example, within the core of the Peruvian oxygen minimum zones oxygen concentrations at nmol levels are present. +- Thus in-situ approaches for 0 % calibration {cite}`Thomsen2016` are suggested. +- Also intercomparisons with STOX sensors attached to a shipboard CTD {cite}`Revsbech2009` or new low-oxygen sensing foils (0-10% saturation) from Aanderaa are recommended. #### 100 / 0 % saturation protocol