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Marine Geochemistry - Laboratory Methods

Laboratory methods

Pore water sampling with Rhizon sampler
method Pore water is sampled directly from sediment using rhizon soil moisture samplers (artificial root). The sampler is connected to a standard syringe using luer-lock fittings and PVC tubing. Evacuating the syringe by drawing the piston is sufficient to withdraw filtered porewater from marine sediments.
setup Horst D.  Schulz“ hands
sampling rate approx. 2 mL / 20 min for a 50 mm length sampler in marine sediment with the setup as above. Sample flow rate may be enhanced by using greater filter length and better vacuum.
pore size 0.15 µm mean (0.2 µm max.)
filter dimensions diameter 2.5 mm x 50 mm length, other sizes and materials available
filter material microporous tube (0.15 µm pore width) supported by a glassfiberepoxy (SS316), nylon or stainless steel wire. (titanium wire on special request)
dead volume less than 0.3 mL (70 to 100 µL  membrane)
advantages direct pore water sampling.
no extra filtering needed since the sampler has a 0.15 µm pore width.
no wet sediment has to be sampled and squeezed or centrifuged.
only a small hole in the sediment is left after sampling.
pore water sampling is even possible through liner caps or through liner wall of closed cores by drilling a 2.5mm hole and pushing the Rhizon sampler in.
50 mm Rhizon sampler connected to standard 2 mL syringe
this is an old picture with  male connector rhizon and a female female adapter to connect syringe.

We now use
19.21.23 F Rhizon CSS 5 cm rhizons with female adapter (blue) that connect directly to the syringe.
pore water yield (approx. 0.5 mL) after 5 minutes. Vacuum is kept by distance piece attached to syringe piston

pore water sampling from closed plastic liner with water saturated marine sediment by drilling 3.8mm holes and gently inserting rhizon pore water samplers.

Sampling with disposable 20 mL syringes.  Syringe holds vacuum by keeping plunger in place with wooden spacer. Rhizons are 5cm flat tip  19.21.23 F Rhizon CSS rhizons with female adapter (blue).

When you stick rhizons into sediment, be sure to hold the tube together with the supporting fiberglass stick firmly between your fingers and thumb ! Do not push the rhizon from the connecting tube between porous part (white) and tubing (transparent) before the rhizon is fully in the sediment.

If sediment is stiff or sandy, use a 2.5mm stainless steel or plastic stick (knitting needle works) to prepare a hole.

the OD of connecting tube is 0.15" or 3.8 mm so it seals perfectly in a 3.8mm hole 

F-F luer adapter vacuum tube
pore water sampling from the open core (gravity corer)
5 cm Rhizon CSS with female luer adapter connected to a 10 mL disposable syringe. The vacuum is kept by a wooden spacer that holds the plunger

Rhizons come with a light blue cap on the luer connector to keep the connector clean. You have to take this cap off !! Otherwise there is no flow!! The caps are perfect to close the syringes after sampling.

For the application above we use a special flat tip version of the Rhizones( Rhizon CSS - Core Solution Sampler), where tip diameter = porous tubing diamter, so the contact between sediment and sampler is very smooth in soft sediments. If sediment is stiff a hole has to be prepared before insertion in order to protect the microporous tube from breaking (i.e. knitting needle of appropiate diameter).
Order numbers from Rhizosphere Research Products -

19.21.01 F Rhizon SMS 10 cm stainless steel support. (pack of 10)
19.21.05 F Rhizon SMS 5 cm stainless steel support (pack of 10)
19.21.21 F Rhizon MOM 10 cm metal-free support. (pack of 10)
19.21.22 F Rhizon MOM 5 cm metal-free support. (pack of 10)
The "Bremen flat tip version" or "Koelling version" now has a separate order number:
19.21.23 F Rhizon CSS 5 cm metal-free support. (pack of 10)

For all Rhizons add "F" to the order number if you want a female luer connector (for directly connecting syringe) instead of the standard male connector (for connecting needle and vacutube)

Rhizons are already widely used in soil science for sampling from non-water-saturated environments. This is possible since - once wettened - the microporous tube is permeable only for liquids - thus keeping attached vacuum in a dry environment.

There is also a porous ceramic (pure Al2O3) version of moisture samplers called Rhizocera (pore width of 0.7 µm, diameter 3mm, length of 50 mm, flow 1ml/min/bar, female luer adapter). (Rhizosphere Research Products order No. 19.21.61)


Rhizosphere Research Products
Dolderstraat 62
NL 6706 JG Wageningen
The Netherlands
+31 317 - 70 80 81

also available from Eijkelkamp Agriresearch (www.eijkelkamp.com)

F.W.Meijboom and M.van Nordwijk (1992): Rhizon Soil Solution Samplers as artificial roots. In: L. Kutschera et. al (Eds.): Root Ecology and its practical Application.- Proc 3rd ISSR Symp., 2.-6. Sep 1991, Wien Austria; pp 793-795.
Seeberg-Elverfeldt, J., and M. Schlüter. patent pended. Probennahmegerät zur simultanen Sammlung von Porenwasser aus benachbarten aquatischen Sedimentbereichen und Anwendung davon - Sampling device for simultaneous collection of pore water from related aquatic sediment areas and applications about it. Reference number: 10 2004 053 111.0-24. Germany
Seeberg-Elverfeldt, J, Schlüter, M, Feseker, T & Kölling, M (2005): Rhizon sampling of pore waters near the sediment/water interface of aquatic systems, Limnology and oceanography: Methods, 3, 361-371.
Kölling, M., Seeberg-Elverfeldt, J., Schlüter, M.(2005). Rhizon - an excellent pore water sampler for low maintenance collection and filtration of small volume samples, EGU General Assembly, 25-29 Apr., Vienna, Austria. Abstract PDF
Seeberg-Elverfeldt, J., Schlüter, M., Kölling, M., Feseker, T.(2005). New Rhizon in situ sampler for pore water studies in aquatic sediments: For example nutrient input from submarine groundwater discharge in costal areas., EGU General Assembly, 25-29 Apr., Vienna, Austria. Abstract PDF
Seeberg-Elverfeldt, J., Kölling, M., Schlüter, M., Feseker, T.(2005). Rhizon in situ sampler (RISS) for pore water sampling from aquatic sediments., In-situ Methods and Investigations in Environmental Science, 230th Meeting of the American Chemical Society, Division of Geochemistry, 28 Aug. - 1 Sept., Washington, DC, USA
Dickens, G.R., Koelling, M., Smith, D.C., Schnieders, L. and the IODP Expedition 302 Scientists (2007): Rhizon Sampling of Pore Waters on Scientific Drilling Expeditions: An Example from the IODP Expedition 302, Arctic Coring Expedition (ACEX).- Scientific Drilling 4: 22-25, doi:10.2204/iodp.sd.4.08.2007

page created by M.Kölling & T.Feseker