U.S. patent application number 11/262034 was filed with the patent office on 2006-05-04 for apparatus for the simultaneous collection of pore water specimens from adjacent areas of aquatic sediments.
Invention is credited to Michael Schlueter, Jens Seeberg-Elverfeld.
Application Number | 20060090894 11/262034 |
Document ID | / |
Family ID | 36217465 |
Filed Date | 2006-05-04 |
United States Patent
Application |
20060090894 |
Kind Code |
A1 |
Seeberg-Elverfeld; Jens ; et
al. |
May 4, 2006 |
Apparatus for the simultaneous collection of pore water specimens
from adjacent areas of aquatic sediments
Abstract
A specimen collection apparatus for the simultaneous collection
of pore water from adjacent areas of aquatic sediments provided
with a plurality of miniaturized tubular specimen collectors in a
vertical array mounted for horizontal movement into and out of a
housing relative to the sediment. A Benthin chamber may be provided
spaced from the specimen collection apparatus such that the
specimen collectors thereof may be moved into the sediment below
the Benthin chamber.
Inventors: |
Seeberg-Elverfeld; Jens;
(Bremen, DE) ; Schlueter; Michael; (Bremerhaven,
DE) |
Correspondence
Address: |
Law Offices of Karl Hormann
P.O. Box 381516
Cambridge
MA
02238-1516
US
|
Family ID: |
36217465 |
Appl. No.: |
11/262034 |
Filed: |
October 28, 2005 |
Current U.S.
Class: |
166/264 |
Current CPC
Class: |
E21B 49/08 20130101 |
Class at
Publication: |
166/264 |
International
Class: |
E21B 49/08 20060101
E21B049/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2004 |
DE |
10 2004 053 111.0 |
Claims
1. A specimen collection apparatus for simultaneously collecting
pore water from adjacent aquatic sediment areas, comprising: a
plurality of miniaturized specimen collectors comprising a
hydrophillic micro-porous plastic hose having means comprising a
pore water intake side and a pore water discharge side; a support
rail at the pore water intake side; a suction device and a storage
device connected therewith at the pore water discharge side; a
housing of substantially blade-like structure with a vertical
narrow surface and provided with a support device for receiving the
specimen collectors with their pore water intake side in alignment
with the narrow surface; and means for horizontally moving the
specimen collectors relative to the sediment areas between a
position out of and a position within the blade-like housing.
2. The apparatus of claim 1, wherein the support device is provided
with a support element for each specimen collector and wherein each
specimen collector is provided with its own means for moving.
3. The apparatus of claim 2, wherein each support element is
structured as a tube rigidly connected to the support device and
wherein the tube receives the specimen collector in its position
within the housing and wherein each means for moving comprises an
angular rail rigidly connected to the specimen collector and a
cable drive.
4. The apparatus of claim 1, wherein the support device is rigidly
connected to and moveable with every specimen collector.
5. The apparatus of claim 4, wherein the means for moving is
provided with a bidirectional cable drive.
6. The apparatus of claim 1, wherein the support device comprises a
support wire made of one of stainless steel and plastic.
7. The apparatus of claim 1, wherein the suction device of each
specimen collector comprises a separate suction element.
8. The apparatus of claim 1, wherein the suction device is
associated with every specimen collector in common.
9. The apparatus of claim 1, wherein the specimen collectors are
structured as Rhizon bottom moisture specimen collectors.
10. A method of using an apparatus of claim 9 comprising the step
of positioning a Benthin chamber at a distance from the specimen
collection apparatus such that the specimen collectors may be moved
into the sediment area below the Benthin chamber.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention, in general, relates to a novel apparatus for
simultaneously collecting specimens of pore water from adjacent
areas of aquatic sediments, and, more particularly, to an apparatus
of the kind referred to provided with a plurality of miniature
specimen collectors arrayed in a housing and provided with a
hydrophillic micro-porous plastic hose connected, at its pore water
intake side, to a support rail and, at its pore water discharge
side, to a vacuum device and a storage device.
[0003] 2. The Prior Art
[0004] Such a specimen collection apparatus is used for
simultaneously collecting of pore water specimens from aquatic
sediments for geochemical and bio-geochemical examinations of the
transition zone between, or at the interface of, sediment and
water. Processes in the sediments and in the bottom water generate
gradients in the pore water, for instance in the concentration of
its. Especially the decay of organic substances and the dissolution
of minerals generate a gradient in the pore water. Pore water is
often examined ex situ by taking a sediment core onboard a ship or
ashore where it is divided into sub-samples. They are squeezed out
under pressure and centrifuged to yield their pore water. However,
such a process may change the chemistry of the pore water as a
result of temperature and pressure changes as well as of
undesirable oxidation and contamination.
[0005] For that reason, in situ systems which examine the sediment
in its natural environment are being used more and more. A
so-called "whole core squeezing" process is known from the paper
"The ROLAI.sup.2D lander: A benthic lander for the study of
exchange across the sediment-water interface" by F. L. Sayles et
al. (Deep-Sea-Research, Vol 38, No. 5, pp. 505-529, 1991)`,
hereafter sometimes referred to as "Publication I", which discloses
depositing on the sediment a free-falling support system ("lander")
for apparatus for examining the bottom of the sea by capturing a
sediment core in a sampling tube. The sediment is squeezed out from
below and from above. The pore water escapes through openings in
the tube into collection containers. Not only is the very
complicated and complex modus operandi of the specimen collector
disadvantageous, but the sediment can only be examined once since
the sediment compound is destroyed during the collection of the
sediment. In view of the fact that the sediment is being compacted
during its compression and is thus moved by the openings in the
specimen tube, it is at best difficult to assign the taking sites
to a defined horizon (depth of sediment).
[0006] The paper "An in situ sampler for close interval pore water
studies" by R. H. Hesslein (Limnology and Oceanography 21(6), Nov.
1976, pp. 912-914), hereafter sometimes referred to as "Publication
II", discloses the so-called "peeper" method which operates on the
principle of diffusion. The sediment receiving apparatus consists
of a corpus with many chambers which are filled with distilled
water and covered my a diaphragm. The specimen collection apparatus
is installed in the sediment and thereafter an equilibrium is
established between the water in the chambers and the pose water.
After an equilibrium has been established the specimen collection
apparatus is retrieved for analyzing the pore water within the
chambers. A drawback inherent in this process may be seen in the
fact that for proper examination of the sediment the specimen
collection apparatus must remain therein for rather a long time.
Moreover, only one examination can be performed so that abrupt
parameter changes in the sediment cannot be detected. Furthermore,
there remains the risk of the equilibrium not having been
established when the specimen collector is being retrieved.
[0007] A third in situ process has been disclosed by the paper "A
new device for in-situ-pore-water sampling" by A. Bertolin et al.
(Marine Chemistry 49 (1995), 233-239), hereafter referred to from
time to time as "Publication III", and involves a suction specimen
collector. The specimen collection device consists of a blade-like
housing the narrow front surface of which defines its size and
which is usually equipped with openings protected by filters or
gauze through which pore water is sucked into storage containers
provided behind the openings, upon application of vacuum pressure.
One disadvantage of this process is the very long adaptation time
of about two weeks the specimen collector requires after being
placed in the sediment before the sediment can be examined.
Furthermore, the pore water is sucked in through relatively large
opening surfaces so that the possible vertical and lateral
resolution are rather poor. Also, the quantity of pore water which
can be taken in is quite limited in cases where it is to be taken
in free of any contamination.
[0008] Every one of the mentioned three apparatus for in situ
processing suffers from the fact that they disturb or destroy the
surface of the sediment when they penetrate into it. The result
will thus be undesirable artificial mixing zones, and the
simultaneous use of a so-called "Benthin chamber" is rendered
impossible. A Benthin chamber is a cylindrical chamber without a
bottom which is placed on the sediment. Any change in the
concentration of substances in the volume of water incubated within
the chamber yields an indication about any exchange or interaction
about the interface of sediment and water. By rotating the lid of
the Benthin chamber or a stirrer within the chamber below its lid a
three-dimensional current can be generated in the interior of the
chamber which will also flow through areas of the sediment. This
arrangement is based upon the recognition that advective currents
greatly affect the movement of dissolved and particulate matter at
the bottom of the sea. A Benthin chamber is a suitable apparatus
for conducting experimental studies of such movements.
[0009] An article "Pore water sampling with Rhizon sampler" by M.
Koelling, hereafter sometimes referred to as "Publication IV", has
been published by the University of Bremen, Germany, and may be
down-loaded at http://www.geochemie.uni-bremen.de/koelling/rhizon
p.html (status 20 October 2004) and relates to the use of
miniaturized specimen collectors with a hydrophillic micro-porous
plastic hose which at its pore water intake side is connected to a
support rail and with a vacuum removal device at its pore water
discharge side. This so-called Rhizon bottom moisture specimen
collector is a miniaturized filter tube with a micro-porous
polymeric hose at its intake side and a vacuum-pressure proof PVC
hose at its discharge side and which represents an artificial root
developed for collecting bottom moisture in unsaturated bottom
zones (see Prospectus P2.30 of the Eijkelkamp company "Soil
Moisture Sampling" pp. 183-186 which may be down-loaded at
http//:www.waterland.com.cn/PDF/P2-30e.pdf, status 20 October 2004
and Prospectus Doc. No. 1190 "Techinfo Ben Meadows Company: Rhizon
Soil Moisture Sampler", 2002 Lab Safety Supply Inc.).
[0010] According to Publication IV by the University of Bremen, the
specimen collector described is used in a specimen collection
apparatus for simultaneously collecting pore water from adjacent
aquatic sediment areas for the ex-situ examination of
water-saturated marine sediment. Hence, the known filter tubes may
be said in some ways to be misused. The sediment to be examined is
initially gathered in a tubular housing which is then moved ashore
and closed by a lid. In the wall of the housing there is provided a
series of small bores disposed parallel to the longitudinal axis of
the housing through which the supported plastic hoses may be
injected into the sediment. The specimen collectors are thus
arranged in a row and each individual pore water specimen gathered
in a storage tube either by way of a small connected vacuum
pressure tube or by way of an injection syringe functioning as a
suction device, can be assigned to an area of the sediment.
Publication IV does not, however, disclose whether the sediment
area extends vertically of laterally relative to the bottom of the
body of water. A disadvantage of this known specimen collecting
apparatus is that it is designed for ex situ pore water examination
and that the injection of the tubular housing into the area of
sediment to be examined results in a substantial disturbance of the
natural ambient conditions. The ex situ measuring process and the
disturbance or destruction of the sediment surface preclude any
measurements accompanying the specimen collection, for instance by
a Benthin chamber.
OBJECTS OF THE INVENTION
[0011] Proceeding upon the apparatus known from Publication IV, it
is an object of the instant invention so to improve a specimen
collecting apparatus with miniaturized specimen collectors that it
can perform in situ examinations of aquatic sediments in vertical
high-resolution.
[0012] Another object resides in the provision of an apparatus of
the kind referred to which is capable of performing examinations
without disturbing the surface of the sediment to allow in situ
accompanying examinations.
SUMMARY OF THE INVENTION
[0013] In the accomplishment of the aforesaid objects the invention
provides for a specimen collection apparatus for simultaneously
collecting pore water from a plurality of adjacent aquatic areas of
sediment and provided with a plurality of miniaturized specimen
collectors arrayed within a housing with a hydrophillic
micro-porous plastic hose provided at the pore water intake side
thereof with a support rail and at the pore water discharge side
thereof with a suction removal device and a storage device, the
specimen collectors being vertically disposed in a support device
within a narrow side of a blade-like housing and connected to a
process unit in which the specimen collectors by the intake side
thereof may be moved into and out of the sediment areas relative to
the housing in the area of the narrow side thereof.
[0014] Other object will in part be obvious and will in part appear
hereinafter.
[0015] An advantageous application of the specimen collection
apparatus of the invention relates to an in situ interaction with a
Benthin chamber placed upon the bottom of the body of water at a
distance from the specimen collection apparatus sufficient to allow
movement of the specimen collectors into the sediment area below
the Benthin chamber without disturbing the sediment surface within
the Benthin chamber.
[0016] The specimen collection apparatus in accordance with the
invention is provided with a number of sample collectors structured
as miniaturized filter tubes of the kind referred to above disposed
vertically within a support device in a blade-like housing. The
support device is arranged within a housing which extends
downwardly in a conical pointed configuration. The blade-like
configuration allows the housing simply to penetrate in a vertical
direction into the surface of the sediment without significantly
damaging the surface of the sediment. Once the housing has reached
its vertical depth of penetration--which is usually within the
upper several decimeters of the layer of sediment--the individual
specimen collectors disposed vertically of each other within the
sediment and thus make possible high-resolution vertical profile
measurements, may be actuated. For this purpose they are
horizontally injected by their supported intake sides from the
narrow front surface of the blade-like housing into the sediment
area adjacent the housing. Thus, the examination is not performed
within the housing, but rather within an undisturbed neighboring
area which as a result of the small diameter of the protruding
specimen collectors is not unduly disturbed. Taking a specimen does
not require a long dwell time. Directly the specimen collectors
have been injected into the sediment the examination may commence.
Several specimens may be collected from the same sediment area by
actuating the suction removal device at predetermined intervals of
time. The pore water specimens may be mixed or stored separately in
appropriate storage devices. Multiple actuation may also take place
by repeated injection and withdrawal of the specimen collectors so
that the chronologically observable conditions within the sediment
may adjust themselves without disturbance by the specimen
collectors,
[0017] In summary, the specimen collection apparatus makes possible
the collection, under in situ conditions, of pore water specimens
from different levels or horizons in the upper decimeters of an
undisturbed aquatic sediment. It allows an examination of pore
water within the sediment in a vertical high-resolution which may
take place once or repeatedly at predetermined intervals of time in
order to allow for examination of chronological changes. The pore
water profiles provided by the specimen collection apparatus may
provide new insight into the motion an reaction processes within
the sediment and at the interface of sediment and water. For
examining the interaction at this interface, the use of the claimed
specimen collection apparatus makes it possible to apply a Benthin
chamber. Hitherto it has not been possible directly to examine the
pore water below such a chamber. By laterally ejecting the specimen
collectors from the blade-like housing of the specimen collection
apparatus it has, however, become possible in view of the fact that
the sediment surface disposed immediately above the specimen
collector is not disturbed or damaged by the specimen collecting
apparatus. In this fashion, it is possible to conduct further
examinations in this area. Accordingly, the specimen collecting
apparatus combines high functionality in keeping with theoretical
demands for a high-quality examination of pore water by an anoxic
examination, a low dead volume in the apparatus and, by the fact
that the pore water is collected in a filtered state because of the
specimen collectors structured as miniaturized filter tubes with a
micro-porous plastic hose for taking in pore water, with a high
suitability for use in the field because of the low disturbance of
the sediment to be examined.
[0018] The basic components of the in situ specimen collection
apparatus are specimen collectors structured as rhizons. Rhizons
are commercially available soil moisture specimen collectors. At
their pore water intake side they usually consist of a piece of
hydrophillic micro-porous polymeric hose glued to a support rail
which may be a stainless steel wire or plastic. Their discharge
side is connected to a PVC hose by means of which a pore water
sample may be sucked by vacuum pressure into a storage device. In
the simplest case, the storage device may be structured as small
tubes; but multiple-chamber storage containers may be used as well.
An unequivocal association of each separate storage container with
its specimen collector is important for establishing a correct
profile curve of every parameter. The suction device may be
manually operable injection syringes or motor-driven peristaltic
pumps. Each specimen collector may be associated with its own
separately actuable suction element. Alternatively, the specimen
collectors may share a common suction device. Manual operation as
well as motorized and automatic actuation of the section device are
possible.
[0019] The specimen collectors are mounted into a support device
such that they may be mechanically moved into the sediment once the
blade-like housing has been pressed into the sediment. A
distinction may be made between two variants: First, each specimen
collector is separately supported and may be separately pushed into
the sediment or, second, all sample collectors are mounted in a
common support device and are pushed into the sediment together. In
the first case, the support for each specimen collector is provided
with a support element for each specimen collector, and for each
support element there is provided a separately actuable movement
element in the movement device. Each support element may be
structured as a tube which is rigidly connected to the support
device and which receives the specimen collector in its withdrawn
state. Hence, the tube function as protective tubes for the
specimen collectors in their withdrawn state. The specimen
collectors are supported by angular rails such that by moving the
angular rails they may be moved as a component of the movement
element out of the forward end of the tubes. For forward and
reverse movement each movement element may be provided with a
bidirectional cable drive. These may be some kind of a "fishing
line" attached by bores at the forward and rear ends of a tube on
the angular rail of each specimen collector. By pulling the
corresponding end of the fishing line (or of separate fishing
lines) and the ensuing movement of the angular rail the specimen
collector may be pushed into or pulled out of the sediment. Each
specimen collector may be actuated separately. However, all cable
drives may alternatively be guided by a common support block so
that, in the manner of a puppet control, that may be actuated at
the same time.
[0020] In the second case of a common support, the support device
is rigidly connected to all specimen collectors, with the specimen
collectors extending out of the support device by their intake
sides, and is structured so as to be movable. In this embodiment,
too, a bidirectional cable drive may be used. It would engage the
forward and rear ends of the support device and by actuation of the
appropriate cable it may move out of and into the support device.
It is also possible to provide motorized as well as automatic
movement by separate or common drives.
DESCRIPTION OF THE SEVERAL DRAWINGS.
[0021] The novel features which are considered to be characteristic
of the invention are set forth with particularity in the appended
claims. The invention itself, however, in respect of its structure,
construction and lay-out as well as its manufacturing techniques,
together with other advantages and objects thereof, will be best
understood from the following description of preferred embodiments
when read in connection with the appended drawings, in which:
[0022] FIG. 1A is a side elevation in cross-section of the specimen
collection apparatus in accordance with the invention;
[0023] FIG. 1B is a frontal view of the specimen collection
apparatus of FIG. 1A;
[0024] FIG. 2 is a detailed view of a specimen collection apparatus
in accordance with the prior art; and
[0025] FIG. 3 is a measuring diagram of two parameters recorded
with the specimen collection apparatus in accordance with the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.
[0026] FIG. 1A depicts in side elevational cross-section a specimen
collection apparatus PNG for the simultaneous collection of pore
water PW from adjacent aquatic sediment areas SB during its used on
the bottom of an ocean. The specimen collection apparatus PNG is
provided with a substantially closed housing SG the downwardly
tapered blade-like configuration and weight of which facilitate a
substantially vertical and stable penetration of the specimen
collection apparatus PNG into the sediment area SB. The frontal
view of FIG. 1 B of the specimen collection apparatus PNG clearly
depicts the blade-like configuration of the housing SG. In a small
forward side SSS of the housing SG six specimen collectors PN are
horizontally arranged within a support device TE. The vertically
stacked arrangement of the specimen collectors PN makes it possible
to determine a vertical measuring profile of predetermined
parameters in the sediment area SB. For this purpose, the specimen
collectors PN may by their intake side ANS be horizontally moved
into and out of the sediment areas SB by the narrow forward surface
SSS of the blade-like housing SG.
[0027] In the embodiment shown in FIG. 1A each specimen collector
PN is movably mounted in a tube RO or support element TEL of its
own which is rigidly connected to a support device TE. The figure
shows the intake sides ANS of the specimen collectors PN supported
by support rails SS in their position extended into the sediment
areas SB. This is accomplished by a movement device VE constructed
of individual movement elements VEL of a number equal to that of
the number of tubes. In the selected embodiment the movement
element VEL is a manually or motor (also automatically) driven
bidirectional cable drive NSZ which is connected to the forward and
rear ends of an angular rail WS rigidly connected to the specimen
collector PN. By actuation of the appropriate end of the cable
drive BSZ the specimen collector PN is pushed out of the protective
tube RO i.e. the support element TEL, so that its intake side ANS
penetrates into the sediment areas SB, or withdrawn from it.
[0028] In another embodiment not shown in FIG. 1A all specimen
collectors PN are rigidly connected to the support device TE. This
may be a simple perforated piece of sheet metal and a central
support rod. All specimen collectors PN extend over the support
device TE by their intake sides ANS. By moving the entire support
device TE the intake sides ANS of the specimen collectors PN may be
moved into and out of the sediment areas SB. The movement device VE
may again be actuated manually or by a motor (also automatically),
for instance by a single bidirectional cable drive BSZ which
engages the support device TE.
[0029] In addition to the specimen collection apparatus PNG FIG. 1A
depicts a Benthin chamber BK placed upon the bottom of the body of
water. Since it has no bottom, it penetrates into the sediment area
SB. By a stirrer RUH, a circulating current affecting the exchange
or interactive processes in the sediment area SB. These may be
detected by the specimen collecting apparatus PNG by the specimen
collectors PN in their laterally expended state examining the
sediment area SB below then Benthin chamber BK without damaging or
destroying the bottom of the water GB within the Benthin chamber BK
and affecting the interactive or exchange processes at the
interface between the water and the sediment. Additional water
specimens WP for comparative measurements may be obtained in the
Benthin chamber BK by way of collective lines SA.
[0030] The specimen collectors PN used are miniaturized filter
tubes, so-called "Rhizon bottom moisture specimen collectors", see
FIG. 2. They are commercially available, but in the specimen
collecting apparatus PNG in accordance with the invention they are
not being used in connection with unsaturated bottoms but, rather,
with bottoms saturated by water. In accordance with FIG. 2 a
specimen collector PN in accordance with the prior art at its pore
water intake side ANS consists of a hydrophillic micro-porous
plastic or polymeric hose KS of a length of, for instance, 5 or 10
cm and a diameter of 2.2 mm with a pore size of 0.2 .mu.m
stabilized by a supportive rail SS. This may be metallic or plastic
stiffening wire. At its pore water PW discharge side ABS the
specimen collector is provided with a PVC hose PVCS by which it is
connected, by way of a connector VB with an injection syringe IS
functioning as a suction removal device ASV with an inter=grated
storage device LV. By means of connecting hoses VSS made of silicon
extension hoses VLS may be connected to the PVC hose PVCS.
[0031] FIG. 3 by way of example depicts two chloride profiles
(chloride in mmol/l above the sediment depth in cm) and two
silicate profiles (silicic acid in .mu.mol/l above the sediment
depth in cm) which resulted from measurements made by the
stationary specimen collection apparatus PNG at the same location
in a sediment area SB on the bottom of a body of water GB at times
A and B. The chronological changes which may be considered to
result from interactive or exchange processes may be clearly seen
in the curves.
* * * * *
References