Presentation

Status of Environmental
Work Carried out by India
Dr. S.K.Das
Ministry of Earth Sciences
Government of India
9th November, 2010
Kingston, Jamaica
Objectives
• To establish baseline conditions of deep-sea
environment in the proposed mining area
 To assess the potential impact of nodule mining
on marine ecosystem
 To understand the processes of restoration and
recolonisation of benthic environment
 To provide environmental inputs for designing
and undertaking a deep-sea mining operation.
Activities and milestones achieved
Activity
Period
Status
• Baseline data collection
1996 - 1997
Completed
• Selection of T & R sites
1997
Completed
• Benthic Disturbance and
impact assessment
1997-2001
Completed
• First monitoring studies
2001-2002
Completed
• Second monitoring studies
2002-2003
Completed
• Third monitoring
2003-2004
Completed
• Fourth monitoring
2005
Completed
• Environmental variability study
2003-2007
Completed
• Evaluation of nodule associated
micro-environ.
Creation of environmental database
2008 onwards
Continuing
2011 onwards
Continuing
Environmental studies for marine mining
in Central Indian Basin
Phase 1: Baseline data
collection
Phase 2: Benthic Disturbance &
Impact Assessment
Phase 3: Monitoring of restoration
modeling of plume
creation of environmental
database
4
PARAMETERS ANALYSED
Geology
•Seafloor features
•Sediment thickness
•Topography
•Sediment sizes
•Porewater and
sediment chemistry
•Geotechnical
props.
•Stratigraphy
Biology
Chemistry
•Surface productivity
•Microbiology
•Biochemistry
• Meiofauna
• Macrofauna
•Megafauna
• Metals
• Nutrients
• DOC
• POC
Physics
• Currents
• Temperature
• Conductivity
• Meteorology
5
Benthic Disturbance (1997)
* 200 x 3000 m
* 5400 m depth
*Central Indian Basin
* 26 tows
* 9 days
* 47 hrs
* 88 km
* 3737 t (wet) / 580 t (dry)
sediment re-suspended
6
Results of different parameters in diff. Phases
(4cm from top in disturbance zone)
Parameter
Sediment sizes
Clay content (%)
Pre-dist. Post-dist. Mon-I
Mon-II Mon-III
(1997) (1997) (2001) (2002)
(2003)
35
40
62
62
56
Geotech.prop.
Water cont (%)
Sh.Str. (Kpa)
544
2.08
563
0.75
463
3.47
567
3.35
616
2.47
Geochem. Prop.
Org.carbon (%)
Nitrogen (%)
Phosphorus (%)
0.35
0.084
0.008
0.35
-0.013
0.37
-0.01
0.46 0.28
0.093 0.085
0.008 0.013
------------------------------------------------(continued…………)
7
Parameter
Microbial
ATP.ug g-1
Pre-dist.
(1997)
Post-dist. Mon.-I
(1997)
(2001)
22.5
Mon-III
(2003)
3.47
1.44
0.00
9.45
106
107
106
106
0.18
0.08
0.21
0.42
0.10
0.52
0.02
0.66
0.07
0.55
0.01
0.83
0.10
0.87
---
46
23
11
6
11
11
4
9
6
10
adenosine triphosphate (ATP)
Total Count.g-1
Mon-II
(2002)
109
Biochemical (mg.g-1)
Chlorophyll
0.16
Proteins
0.42
Lipids
0.29
LOM
0.88
(Labile Organic Matter)
Meiofauna (no.10 cm-2)
Abundance
No. of groups
Macrofauna (no.m-2)
Abundance
244
80
266
--
100
8
Monitoring of restoration of benthic environment
Pre disturbance – 1997
Post disturbance – 1997
Monitoring I
-- 2001
Monitoring II
-- 2002
Monitoring III
-- 2003
Monitoring IV
-- 2005
Test area
Reference area
80
70
60
50
40
30
20
10
0
80
Av. clay % of different phases for 0 to 4 cm depth
DZ
70
Av. clay % of different phases for 0 to 4 cm depth
A1/A
60
Clay %
Clay %
Concentration of clays at test and reference locations
EDZ
50
A1/B
40
30
20
NDZ
A1
10
0
Pre. D. Post. D.
M-1
M-2
M-3
M-4
SDZ
Baseline
M-1
Phases
M-2
M-3
M-4
0-4 cm
0-4 cm
Test area
Reference area
Avg.
Conc.
Clay (%)
T1/B
Phases
Pre
Post
Mon.I Mon.II
Mon.III
Mon.IV
(June 97)
(Aug 97)
(Apr 01)
(June 02)
(Apr 03)
(Apr 04)
35
40
62
62
56
68
Geotechnical properties in different phases
Average
Post
Mon.I
Mon.II
Mon.III
Mon.IV
(Jun 97)
(Aug 97)
(Apr 01)
(Jun 02)
(Apr 03)
(Apr. 05)
544
563
463
567
616
503
Shear strength (Kpa) 2.08
0.75
3.47
3.35
2.47
3.00
Values
Water Content (%)
Pre
Organic carbon and nitrate concentrations in different phases
Average
(%)
OC
Pre-dist.
Post-dist.
(Jun. 97)
(Aug. 97)
0.35
0.46
Mon.-I
Mon.-II
Mon.-III
Mon.-IV
(Apr. 01)
(Jun. 02) (Apr. 03)
(Apr.05)
0.28
0.35
0.37
0.31
Macrofauna distribution in different phases
12
200
10
229
150
179
177
100
50
66
64
No. of groups
Density (no.m-2)
250
8
6
4
2
Mon-IV
Mon-III
Mon-I
Postdist
Pre-dist
0
0
Pre-dist
Test area (average density)
Station 2
Station 3
Station 5
-2
Density (no.m )
400
300
200
Mon-IV
Mon-III
Pre-dist
Mon-I
100
0
No. m-2
Mon-IV
A1/a
A1/b
T1/b
Mon-III
Mon-IV
Reference area (station wise)
Pre-dist.
Post-dist.
Mon.-I
(Jun. 97)
(Aug. 97)
(Apr. 01)
229
Mon-III
250
225
200
175
150
125
100
75
50
25
0
Mon-I
Test area (station wise)
Average
abundance
Mon-I
Test area (cumulative groups)
500
Post-dist
Density (no.m -2)
600
Post-dist
179
177
Mon.-II
Mon.-III
Mon.-IV
(Jun. 02) (Apr. 03)
(Apr.05)
--
66
64
Meiofauna distribution in different phases
50
30
Disturbance area
Disturbance track
45
25
Density (no.10cm -2)
Density (no.10cm -2)
40
35
30
25
20
15
10
5
20
15
10
5
Mon-IV
Mon-III
Mon-II
Mon-I
Pre-dist
Post-dist
0
0
Mon-I
Test area (mean density)
12
Mon-III
Mon-IV
Reference area (mean density)
11
10
10
No. of groups
Mon-II
Avg.
PreValues dist.
9
8
6
Post
dist.
Mon-I
Mon-II
Mon-III
Mon-IV
(Jun 97) (Aug 97) (Apr 01) (Jun 02)(Apr 03)(Apr05)
6
4
4
4
2
46
23
17
6
11
6
Groups 11
4
9
6
10
4
Abund.
Test area (cumulative groups)
Mon-IV
Mon-III
Mon-II
Mon-I
Post-dist
Pre-dist
0
Cells.g-1 dry sediment
Microbial distribution in different phases
1.00E+10
1.00E+07
1.00E+04
pre-
po Moni Moni Moni Moni
st1
2
3
4
Sampling stage
Reference area (total count)
10000
100
po
s
M t
on
i
M 1
on
i2
M
on
i
M 3
on
i4
1
pr
e
ATP ng.g-1dry sediment
Test area (total count)
Sampling stages
Test area (ATP)
Reference area (ATP)
Salient findings of benthic impact experiment
Immediate impact
•
Lateral migration of sediment
•
Vertical mixing of sediment
•
Changes in physicochemical conditions
•
Overall reduction in biomass
BC9
Longterm restoration
75.99
-10.02
76.00
76.01
76.02
76.03
-10.02
BC12
MC02a
BC4
•
BC13
Restoration started initially
MC01
BC5
BC10
BC8
-10.03
High sediment influx
BC17
BC3
BC14
Latitude (°S)
•
-10.03
BC11
BC7
•
Conditions fluctuating annually
•
Large local variations
-10.04
BC2
BC15
-10.04
BC16
BC6
BC1
-10.05
75.99
76.00
76.01
76.02
Longitude (°E)
These observations suggest that the background changes
mask the experimental changes over a period of time
-10.05
76.03
Temporal and spatial variability of environment
April-May 2003
72.0
-10.0
72.5
73.0
73.5
74.0
74.5
75.0
April-May 2005
75.5
76.0
76.5
BC-1R
BC-26
-10.5
77.0
-10.0
-10.5
-11.0
BC-23
BC-24
BC-25
BC-2RR
-11.5
-12.0
BC-21
BC-22
BC-3R
BC-20
-11.0
-11.5
Rel. Area - Phase I
-12.0
Rel. Area - Phase II
Rel. Area - Phase III
-12.5
-12.5
Latitude(°S)
Retained Area
-13.0
BC-19
BC-18
BC-17
BC-4
-13.5
-13.5
-14.0
BC-15
BC-16
BC-5
BC-14
-14.5
-14.0
-14.5
-15.0
BC-11
BC-12R
BC-6
BC-13
-15.5
-15.0
-15.5
-16.0
-16.5
72.0
-13.0
BC-10
72.5
73.0
73.5
BC-9
74.0
74.5
Longitude (°E)
BC-8
75.0
75.5
BC-7
76.0
76.5
-16.0
-16.5
77.0
Coring stations
Multi-beam and parasound data in PMN area
Evaluation of
depth variation and
sediment thickness
• N-S transect
• E-W transect
Depths and sediment thickness data along N-S transect (75o 30’E, 10o - 16o)
Sl.No
.
Depths between 10 - 12º
S are relatively higher
(5250-5340 m) with
respect to south i.e.1216º S (4900-5230 m).
Sediment thickness
generally higher in the
north (30-70 m) as
compared to the south
(10-15 m).
Station
Number
Depth (m)
Sediment thickness
(m)
1.
TVBC 26
5338
70
2.
TVBC 25
5292
50
3.
BC 28
5266
30
4.
TVBC 20
5239
50
5.
BC 30
5180
-
6.
TVBC 19
5096
-
7.
BC 34
5225
10
8.
TVBC 14
5189
15
9.
BC 35
5237
10
10.
TVBC 13
4899
15
11.
TVBC 8
5201
10
Depth and sediment thickness along E-W transect (13o S, 74o 30’-76o 30’)
•The eastern section is
deeper than the western
section of the transect
•The deepest point on west is
5150 m, while center is 5250
m and in the east is 5650m
•Sediment thickness varies
with the seafloor topography,
i.e. less thickness on peaks
and higher thickness on
slopes and valleys.
Depth and sediment thickness in First Gen. Mine-site
General depth varies between
5000 – 5400 m, which include
bathymetric highs (hills),
slopes and valleys.
Sediment thickness varies
with the seafloor topography,
i.e. less thickness on peaks
and higher thickness on
slopes and valleys.
Relation of sediment thickness with seafloor topography
Seafloor depth
Sed. thickness
Hilltop (n=4)
• All the valleys are between
5150 – 5400 m.
Hill tops
Frequency %
30
25
20
15
10
5
0
60
50
40
30
20
10
0
59.
99
10
-1
4.
99
15
-1
9.
99
20
-2
4.
99
25
-2
9.
99
30
-3
4.
99
• Most hill tops are located
at depths of 5000-5150 m
Frequency %
Hilltop (n=4)
49
99
49
99
49
-50 0-50 0-51 0-51 0-52
0
0
5
0
5
0
50
50
51 Depth
51 (m5)2
Thickness (m )
slope (n=9)
• Sediment thickness on the
slopes is intermediate (1020 m)
5
0
Thickness (m )
Valley (n=7)
valley (n=7)
50
40
30
20
10
0
Frequency %
Frequency %
• Sediment thickness in the
valleys is the maximum
(35-60 m).
15
10
04.
99
9
10
-1
4.
99
20
-2
4.
99
30
-3
4.
99
40
-4
4.
99
50
-5
4.
99
Slopes
25
20
Frequency %
• Sediment thickness at most
of the hill tops is the lowest
(< 10 m)
49
99
49
99
49
00
-50 -50 -51 -51 -52 -53
00 050 100 150 200 250
0
5
5
5
5
5
5
Depth (m )
Valleys
30
25
20
15
10
5
0
9
9
9
9
9
9
.99
4.9 4.9 4.9
4.9 4.9
0-4 10-1 20-2 30-3 40-4 50-5
Thickness (m )
TVBC-26
16
12
TVBC-25R3
14
10
BC-28
12
BC-29
TVBC-20
10
BC-30
(20-50%)
40-45
35-40
30-35
25-30
20-25
15-20
8-10
BC-27 R
TVBC-25R3
80
BC-28
70
BC-29
60
BC-30
50
BC-31
40
BC-32
30
BC-33
BC-34
20
TVBC-14
10
TVBC-08 R
Depth (cm)
FGM
40-45
35-40
30-35
25-30
20-25
15-20
0
10-15
TVBC-13
(40-80%)
6-8
BC-35
TVBC-03
ABP-04, FGM
4-6
Clay
2-4
35-40
25-30
TVBC-19
TVBC-20
Depth (cm)
90
TVBC-19
15-20
TVBC-18
TVBC-26
BC-30
8-10
TVBC-04
40-44
TVBC-13
TVBC-20
4-6
TVBC-03
0
BC-28
0-2
BC-33
0-2
90
80
70
60
50
40
30
20
10
0
N-S profile
20
TVBC-08 R
Depth (cm)
Depth (cm)
BC-32
0-2
35-40
25-30
15-20
8-10
4-6
0-2
BC-35
30
10
TVBC-14
0
BC-31
35-40
BC-34
BC-30
40
30-35
10
Silt
BC-28
BC-29
25-30
TVBC-19
TVBC-19
50
20-25
20
ABP-04, FGM
15-20
BC-30
Silt %
Silt %
TVBC-20
TVBC-18
TVBC-20
BC-27 R
60
BC-28
30
10-15
TVBC-25R3
10-15
50
Depth (cm)
70
8-10
60
TVBC-04
0
TVBC-13
TVBC-08 R
TVBC-26
40
Clay %
BC-35
8-10
Depth (cm)
TVBC-03
2
6-8
35-40
25-30
15-20
8-10
4-6
0-2
0
(<8%)
6-8
TVBC-14
BC-33
4
4-6
2
BC-32
6
4-6
BC-34
BC-28
BC-31
8
2-4
TVBC-19
4
Sand
2-4
BC-30
6
BC-27 R
ABP-04, FGM
0-2
8
Sand %
14
Clay %
Sand %
Concentrations of sand-silt-clay in sediment samples
TVBC-04
TVBC-18
TVBC-19
TVBC-20
Average sand-silt-clay content (N to S) along 75.5o E profile
Sr. No.
Lat.
(oS)
Sample No.
Average
Sand %
Silt %
Clay %
1
10
TVBC-26
2.08
35.94
62.04
2
11
TVBC-25R3
2.44
34.21
63.36
3
11.5
BC-28
1.40
30.48
68.12
4
12
TVBC-20
2.97
37.70
59.34
5
12.5
BC-30
2.37
35.37
61.84
6
13
TVBC-19
3.70
32.72
63.58
7
13.5
BC-34
3.76
36.46
59.77
8
14
TVBC-14
1.67
31.05
67.28
9
14.5
BC-35
6.52
44.27
49.22
10
15
TVBC-13
1.93
29.07
69.00
11
16
TVBC-08 R
0.47
22.21
77.32
Silt decreases, clay increases from N-S
(BC-35 shows exceptional values)
Temporal variation of sediment particles
Sr.
no.
Latitude
(o S)
EVD-I (April 2003)
1
10
BC-26
62.05-79.25
TVBC-26
49.20-74.10
2
11
BC-25
41.71-74.12
TVBC-25 R3
51.55-70.95
3
12
BC-03 RR
60.77-74.02
TVBC-03
51.11-78.33
4
12
BC-20
45.41-66.36
TVBC-20
52.69-69.69
5
13
BC-04
35.46-55.19
TVBC-04
33.45-64.24
6
13
BC-18
47.28-72.29
TVBC-18
47.70-71.97
7
13
BC-19
49.66-81.04
TVBC-19
38.93-79.10
8
14
BC-14
51.20-71.34
TVBC-14
57.87-78.58
9
15
BC-13
41.79-62.32
TVBC-13
52.69-78.26
10
16
BC-08
55.48-77.56
TVBC-08 R
72.18-82.84
Station no.
EVD-II (April 2005)
Clay %
Station no.
Clay %
Figs. in orange show the range in different phases
Sediment texture is ‘silty clay’ in both phases
Clay (<4 micron) is the major component (~40-80%), silt (4-64 micron) is
intermediate (20-50%), sand (>64 micron) is the least (< 10%)
Shows minor temporal variations (maximum and minimum are same)
Geotechnical properties of sediments in CIB (including FGM)
Water
content
(%)
Specific
gravity
Wet bulk
density
(g/cm3)
Porosity
(%)
Shear
strengt
h (kPa)
Minimum
(bottom)
121
1.59
1.09
75.5
1.44
Maximum
(top)
729
2.58
1.42
90.3
11.5
Average
453
2.21
1.15
75.5
4.37
Temporal variability of geotechnical properties of sediments
Water content
Shear strength
(Pink: EVD-I, Blue: EVD-II)
Spatial variability of water content of sediments
10-11.30 o
12-13 o
13-14 o
14-15 o
15-16 o
Alternate bands of high and low values, also for shear strength
Temporal variation of meiofauna
20
Density of meiofauna
ABP-04
AAS-61
5
26
BC
-2
5
TV
0
TV
BC
BC
-2
9
Stations
TV
BC
-1
18
TV
4
TV
BC
-
BC
-1
3
TV
BC
-1
08
TV
04
TV
BC
-
3
0
TV
BC
-
• and organic carbon supply
10
BC
-0
• may be due to surface
productivity
15
TV
• less in 2003 than 2005
Meiobenthic density (no.10cm-2)
• variable at different locations
Vertical distribution of meiofauna
N-S profile
FGM
Meiobenthic density (%)
0
5
10
Meiobenthic density (%)
0
15
2
4
6
8
10
12
14
0 -0.5
0 -0.5
0.5-1.0
1.0-1.5
1.0-1.5
1.5-2.0
2.0-4.0
Nematoda
6.0-8.0
Harpacticoida
Polycheata
10.0-12.0
Halacarida
Nemertina
14-16
18-20
25-30
Sediment depth (cm)
Sediment depth (cm)
2.0-4.0
4.0-6.0
6.0-8.0
8.0-10
10.0-12.0
12.0-14.0
14-16
Nauplii
16-18
Crustacea
18-20
Tardigrada
20-25
Ostracoda
25-30
Nematoda
Harpacticoida
Polycheata
Turbellaria
Halacarida
Nemertina
Nauplii
Crustacea
Tardigrada
Ostracoda
30-35
35-40
9-10 common groups, Nematoda most abundant group at all
depths, ~75% fauna in top 10 cm of sediment column
Distribution of major macrofaunal groups
Spatial variability
Temporal variability
Spatial variability of m acrofauna (75.5 degrees)
Tanaidacea
7%
Abundance of macrofauna (%) during the March 03
cruise
Harpacticoida
15%
H a la c a rid
7%
Bivalvia
5%
Other
9%
P olychaete
34%
P o lyc ha e t e
60%
T a na id
11%
Isopoda
2%
Is o po d
4%
G a s t ro po d
7%
La rv a e
( unide nt if ie d)
7%
Unidentified
2%
Nematodes
35%
Fig 7.13: Macrofaunal anbundance in the first
generation mine site
N-S profile
N e m a t o de
4%
April ‘03
Abundance of m acrofauna (%) during April 05 cruise
Polychaeta
24%
Tanaidacea
8%
Nem atode
48%
Harpacticoida
15%
Bivalvia
2%
Isopoda
2%
Nematodes
49%
FGM
Bivalvia
5%
Isopod
3%
Tanaid
10%
April ‘05
Polychaete
34%
Vertical distribution of macrofauna in sediment cores
Abundance (%)
Depth (cm)
0
20
40
60
0-2
80
Apr-05
Mar-03
2--5
5--10
10--15
25--30
Fig 7.4: Temporal variation in the vertical distribution
of macrofauna
Macrofauna
0
10
Abundance (%)
20
30
Temporal
40
Abundance (%)
50
0
20
30
40
50
0--2
2--5
5--10
Nematoda
Harpacticoida
Tanaidacea
Polychaeta
Isopoda
Oligochaeta
10--15
15--20
25--30
Fig 7.8: Vertical distribution of macrobenthos
along the 75.5 degree longitude
N-S profile
Depth (cm)
Depth (cm)
0-2
10
2--5
Nematoda
Polychaeta
5--10
Harpacticoida
Isopoda
10--15
15--20
Fig 7.14: Vertical distribution of macrofauna (%)
in the First generation mine site
FGM
Temporal and spatial variability is evident,
> 75% of macrofauna in top 10 cm
Phases of observations and parameters analysed
Phases of observations
Parameters analysed
•Nodule size and morphology
Env. Variability-1 (April 2003)
•Sediment size classes
Env. Variability-2 (April 2005)
• Geochemistry of sediments
and porewaters
Env. Variability-3 (Decem. 2006)
• Geotechnical properties
• Nodule associated fauna
Env. Variability-4 (Sept 2009)
• Meiofaunal diversity
• Microbiology and biochemistry
• Fungal diversity
Sediment texture – silty clay
Silt (4-63µ)
Clay (<4µ)
0.2-13.9%
2.4- 3.0 %
18-50%
34-44 %
47-72%
59-63%
0.38-5.5%
1.70-2.6%
27-52%
36-41 %
Sand(63µ-2mm)
BC 18
Range*
Average**
BC 20
Range*
Average**
* For ~10 subsections each of 4 cores taken during different seasons/years
** For 4 cores taken during different seasons/years
45-69%
52-61%
Geotechnical properties
Parameter/ Stn.no.
BC 18
BC20
Water content -Range
355-720
325-729
489
506
2.15-7.54
1.46-6.82
(%)
- Avg.
Shear strength-Range
(kPa)
- Avg.
4.275
3.533
Sp. Gravity
- Range
1.88-2.49
2.02-2.51
2.22
2.2
88.9-94.4
88-93.9
91.3
91.6
1.11-1-17
1.11-1.18
1.14
1.3
- Avg.
Porosity
- Range
(%)
- Avg.
Wet density
- Range
(g/cc)
- Avg.
Geochemical properties
Parameter
EVD-I,II,III
EVD-IV
Remarks
OC - Surface (0-10 cm)
- Subsurface (>10 cm)
0.20 - 0.4 %
0.02 - 0.2 %
0.02 - 0.2 %
--do--
lower
same
pH - BC 18
- BC 20
7.4 - 7.6
7.2 - 7.4
7.5 - 7.7
7.4 - 7.45
higher
higher
Indicate removal of top layers of sediments (similar
to mining experiment) due to some natural events
or variation in supply of fluxes from water column
Nutrients
Range in different seasons / years (µM)
Silicates
Nitrites
Phosphates
300-600
0.1 - 0.8
1.0 - 3.0
Vary over a wide range in different time scales
Have a symbiotic relation with benthic fauna
Microbial and biochemical properties
no. g-1 dryw t
1.00E+04
0
1.00E+10
5
EVDC I
EVDC II
1.00E-02
IVBC 18C Proteins
2
EVDC I
6
EVDC II
EVDC III
8
IVBC 18C TC
50
1.00E+00
2
4
EVDC I
6
EVDC II
1.00E+04
0
1.00E+06
5
EVDC I
10
EVDC II
1.00E-02
1.00E-01
1.00E-03
0
1.00E+00
1.00E-02
1.00E-01
1.00E+00
2
8
EVDC II
EVDC III
4
EVDC I
6
8
IVBC 20A TC
EVDC II
Proteins
4
EVDC I
6
8
IVBC 20A Carbohydrates
Total counts
(in all seasons/yrs)
IVBC 18A LOM
EVDC II
EVDC III
EVDC III
10
10
1.00E-02
EVDC IV
EVDC IV
EVDC IV
45
depth(cm)
EVDC I
depth(cm)
depth(cm)
40
EVDC IV
mg/g dryw t
2
4
35
EVDC II
1.00E-03
0
IVBC 20A Proteins
2
6
1.00E+00
EVDC I
6
mg/g dryw t
EVDC III
30
1.00E-01
4
10
mg/g dryw t
1.00E+10
EVDC IV
1.00E+00
IVBC 20A LOM
8
10
1.00E-03
0
1.00E-01
EVDC IV
10
1.00E+08
1.00E-02
EVDC III
EVDC III
8
no. g-1 dryw t
depth(cm)
1.00E-01
IVBC 18C Carbohydrates
EVDC IV
45
50
1.00E-02
1.00E-03
0
depth(cm)
4
35
40
depth(cm)
depth(cm)
EVDC IV
30
25
1.00E-03
0
1.00E+00
2
25
20
1.00E-01
EVDC III
20
15
mg/g dryw t
mg/g dryw t
mg/g dryw t
1.00E+08
1.00E-03
0
10
15
depth(cm)
1.00E+06
Carbohydrates
10
LOM
(mg/g)
(mg/g)
(mg/g)
BC 18
4.98x107-1.10x108
0.03-0.09
0.011-0.029
0.39-0.52
BC 20
5.43x106-1.43x108
0.2-0.6
0.005-0.024
0.04-0.35
Lowest values in EVD-IV out of all 4 observations (EVD I-IV, 2003-2009)
All parameters vary significantly between seasons / years
Fungal diversity
• 19 cultures, 14 species isolated
• Growth under high pressure
conditions confirms presence in
deep-sea
• Different media used for
culturing deep-sea fungi
• Potential for production of useful
enzymes and drugs
Top: Cerrena sp., Trametes sp. (Mangroves)
Bottom: Cerrena sp., D. Trametes sp. (Deep-sea)
Isolate
Fungi
Core
Section(cm)
Method
Medium
F51
Nigrospora sp.
BC-18C
8-10
PI
MEA
F52
Cladosporium sp.
BC-18C
10-15
PI
CDA
F53
Trametes sp.
BC-18C
0-2
PI
MEA
F54
Chaetomium sp.
BC-18C
8-10
PI
PDA
F55
Aspergillus sp.
BC-18C
4-6
PI
CDA
F56
Ascotricha sp.
BC-18C
10-15
PI
MEA
F57
Pleospora sp.
BC-18C
20-25
PI
PDA
F58
Cladosporium sp.
BC-18C
2-4
PI
PDA
F59
Eurotium sp.
BC-18C
0-2
PI
MEA
F60
Cerrena sp.
BC-18C
30-35
PI
PDA
F61
Cerrena sp.
BC-18C
20-25
PI
SDA
F62
Penicillium sp.
BC-20A
20-25
PP
CMA
F63
Penicillium sp.
BC-18C
35-40
PP
PDA
F64
Aspergillus sp.
BC-18C
4-6
PP
CDA
F65
Sagenomella sp.
BC-18C
6-8
PP
MEA
F66
Cerrena sp.
BC-20A
4-6
PI
MEA
F67
Cerrena sp.
BC-20A
15-20
PI
SDA
F68
Hortaea sp.
BC-20A
15-20
PP
CMA
Y14
Hortaea sp.
BC-20A
6-8
PP
PDA
Nodule associated fauna
• 109 nodules analysed from 6 samples (2 stns.)
• 30-80% nodules (avg. 40%) have associated fauna
• 10 groups of meiofauna identified
• Nematoda (30%), herpacticoida (20%),
polychaetes (15%) dominate
Nematode associated with nodule from CIB
Nodule as s oc iated meiofauna at s tn 18C
P olyc haeta
15%
• 1-14 individuals per nodule
Tanaidac ean
10%
Nematoda
30%
Is opoda
10%
B ivalves
15%
• 2-8 groups of meiofauna per nodule
O ribatida
10%
O rbitadea
15%
• Nodule morphology plays a major role in
hosting sediments with faunal groups
Harpac tic oida
12%
F oraminifera
11%
Harpac tic oida
25%
K inorhync ha
10%
Nodule as s oc iated fauna at 19D
Faunal diversity associated with nodules
6
y = 0.0238x + 2.017
R2 = 0.112
16
14
y = 0.0176x
R 2 = -0.349
5
12
10
8
6
y = 0.042x
R2 = 0.0246
4
2
Taxa (Nodule -1)
Individual (nodule -1)
• Nodule surface area and faunal abundance have
weak correlation
Nematoda
27%
C nidaria
10%
4
3
2
y = 0.0032x + 1.5997
R 2 = 0.0132
1
0
0
50
100
150
Nodule surface area (cm-2 )
200
0
0
50
100
150
Nodule surface area (cm-2 )
Faunal abundance with nodule surface area
200
Macrofaunal community
• 30 taxa belonging to 11 groups from 6 samples (2 stns.)
• Avg. abundance 316 no./m2 (stn. 18) and 148 no./m2 (stn. 19)
• Tanaids (35%), polychaetes (22%), amphipods (20%) dominate
• Fauna belonging to 10 groups (stn. 18) and 4 groups (stn. 19)
Mean macrobenthic abundance (no. m-2) at Stn. IVBC-18
Group
Mean±sd
%
Polychaeta
103.5 ± 106.5
32.8
Nemertinia
5.3±13
1.7
Oligochaeta
7.1±17.3
2.2
Amphipoda
72.5±33.1
23.0
Harpacticoida
12.4±19.5
3.9
Isopoda
15.9±26.6
5.0
Tanaidacea
81.3±51.4
25.8
5.3±13
1.7
Prawn
7.1±17.3
2.2
Bivalvia
5.3±13
1.7
Pycnogonida
Macrobenthic abundance (no. m-2) at station IVBC-19
Mean abundance
±sd
Composition (%)
Minor phyla
21.2±30
14.3
Amphipoda
21.2±30
14.3
Isopoda
21.2±30
14.3
Tanaidacea
84.8±2.3
57.1
Group
Water column characteristics
CTD-18A
CTD-19A
Temperature varied from 26o (surface) to1.5o (3000m)
Steep temperature decline upto ~400 m
Salinity remained constant except at ~ 400 m
Surface temperature is 24-29o C from 12o N to 12o S
XBT 1-20
Overall conclusions
These studies have shown that environmental conditions
no. g-1 dry sediment
TC-M3
1.00E+09
1.00E+06
1.00E+03
pre-
post-
• vary over different time scales (seasonal and annual)
Moni 1
Moni 2
Moni 3
Moni 4
LOM-M3
• on a wide range, but always follow a particular trend
mg g-1 dry sediment
5.000
4.000
3.000
2.000
1.000
0.000
pre-
post-
Moni 1
Moni 2
Moni 3
TC and LOM during monitoring phases at BC-3
Implications
These variations could
probably well
encompass the
changes in conditions
created by other
activities such as
deep seabed mining.
Org C during EVD-I,II,III,IV
Org C during pre, pot-dist, monitoring at BC-2,3,5
Environmental variability - conclusions
1. Bathymetry and sediment thickness
•
Seafloor deeper in N (5250-5340 m) than S (4900-5230 m)
•
Sediment thickness higher in N (30-70 m) than S (10-15 m)
•
Most hilltops between 5000-5100 m, valleys 5150-5400 m
•
Sediment thickness least on hilltops (<10 m), intermediate on
slopes (10-20 m), maximum in valleys (35-60 m)
2. Sediment texture
•
Silty clay in entire area
•
Sand (<8%), silt (20-50%), clay (40-80%)
•
Silt content decreases, clay increases from N-S
•
Minor temporal variations locally
Environmental variability - conclusions
3. Geotechnical properties
•
High water content (500-700%) on top, low (300-400%) at bottom
•
Low shear strength (2-3 kPa) on top, high (5-8 kPa) at bottom
•
High-low bands in WC and SS from N-S
•
Localised temporal variability
4. Faunal distribution
•
>75% fauna in top 10 cm
•
9-10 groups common at all locations and in all observations
•
Similar distribution of groups, but concentrations may vary
•
Different temporal variations between locations
Modeling of sediment plume dispersion
Model capabilities
• sediment dispersion of plume
and settling
• takes into account processes
including advection, dispersion

•· predicts suspended and bed load
sediment movement
After 1 hour
• specialized features for graphics
and post-processing
After 20 hours
Concluding Remarks
• Studies carried out over one decade indicates
that the nodule area of CIOB is comprised of
highly heterogeneous environmental conditions in
terms of spatial variations.
•The Sea floor as well sediments have undergone
relatively more intense impact within the disturber
track and little or no impact in the north of
disturbance zone.
• The monitoring of environmental conditions after
the benthic disturbance experiment indicates that
the benthic conditions are steadily moving
towards restoration and the effect of disturbance
is waning off.
•These studies have shown that environmental
conditions vary over different time scales
Platforms used
• RV Akademic Alexander Sidorenko
• RV Yuzhmorgeologiya
• RV Boris Petrov
•THANK YOU
Benthic Impact Experiments (BIEs)
-----------------------------------------------------------------------------------------------------------------
Expt.
Tows
Duration
Distance Discharge
78
~12days
10.8 sqkm
-----------------------------------------------------------------------------------------------------------------
DISCOL*
(German)
NOAA
49
5290
(USA)
JET
19
1227
(Japan)
IOM
14
1130
(Inter Ocean Metal)
INDEX
26
2534
(India)
--
mins
141 km
6951 cu.m.
mins
33 km
2495 cu.m.
mins
35 km
2693 cu.m.
mins
88 km
6015 cu.m.
* DISCOL was conducted with plow harrow and other49expts.
were. conducted with hydraulic suction device