Biological Communities Associated with the Indian Ocean Seamounts

Baban Ingole

National Institute of Oceanography,

Dona Paula, Goa 403 004, India

OutlineWhat we known about the

Indian Ocean seamount biology? - (available data as well as New data)

Identify the gaps Proposed national & international studies.

INDIA

Worlds second largest & second high grade manganese nodule deposit.

Over 10000 seamounts –many have potential of cobalt rich

Mid Ocean Ridge system –potential for sulphidedeposits

In last 25 years >70deep-sea expeditions.

400 seabed samples & 55000 still phto & few kms of deep tow photography for benthic studies Potential for many new spp.

But non of the study was aimed at seamount biology

CIOB

Central Indian Ocean Basin (CIOB) Somali Basin; Madagascar Basin; Arabian Sea; Central Indian Ridge (CIR); Carlsberg Ridge (CR) Rodriguez Triple Junction Andaman Back-Arc Basin (ABAB)

Area of interest

Bathymetry and morphology of the central Indian Ocean (Kodagali & Raju, 1992)

(Kodagali & Raju 1992)

BASINAL SEAMOUNTS AND SEAMOUNTS CHAINS OF THE CENTRAL INDIAN OCEAN (Mukhopadhyay et al 2002)

In facts app. 6000 seamounts of small (> 100 m), medium (>500m0 and large (>1500m) are recorded from Indian Ocean nodule field

Afanasij Nikitin Unknown Unknown Unknown Unknown

Scherbakovunknown Walters Farquhar Equator Equator Walters Shoals

Unknown

Among >10000 seamounts, biological features are known only from 16; mainly from the fishery surveys

AfanasiyAfanasiy--Nikitin Nikitin seamount in the CIOBseamount in the CIOB

Many of the rock samples have thick coating of ferromanganese oxides.

Cobalt Crust

dredging & sediment sampling indicated presence of highly diverse in benthic communities

Fish Catch statistics of Soviet/Ukrainian vessels on Southwestern Indian Ridge Seamounts (FAO 2003)

1472

60295472

21121720

152 153 34

583

36 15 10

1676 1500

26332970

3480

1570 1623

3303

2015

810

0

1000

2000

3000

4000

5000

6000

7000

8000

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

Tota

l cat

ch (t

)

Highest catch (6029 t) recorded in 1980.& Lowest (10 t) in 1991. Main target species were alfonsino(Beryx splendens), two species ofrubyfish & two spp. butterfish

Alfonsino, Baryx splendens, accounted for 45% of the total average catch.

Figig. Composition of major fish species

01020304050

Beryx splendensEmmelic

hthys sppCentro

lophidae

Trachurus picturatusSelachim

orphaPolyprio

n spp.Cat

ch C

ompo

sitio

n (%

)

0

500

1000

1500

2000

2500

3000

3500

1975 1980 1985 1990 1995 2000 2005Years

Fish

Cat

ch (T

onne

s)

Baryx splendens

Seamounts (120)

Butterfish

59%

Rubyfishes

18%

Cardinalfish12%

Alfoncinos

11%Jack

mackerel

0.3%

Others0.3%

Seamounts(150)

Jack mackerel

1 3 %

O thers2 %

Cardinalfish

0 %

Rubyfishes8 3 %

A lfoncino0 %

Butterfish2 %

Trawl surveys conducted in 1980-1981 at the Southwest Indian Ridge seamounts Suggested that individual seamount may have different catch composition (Nikolaj et al., FAO 2003)

Vertical distribution of zoopl. (ind./m2) on the region of Equator Seamount (Voronina & Timonin, 1986)

0

500

1000

1500

2000

2500

3000

3500

4000

Acroca

lanus gracili

s

Neocalanu

s gracili

s

Undinulia da

rwini

Acartia

negligens

Lucicu tia fla

vicorni

s

Euchaeti

a spp

Sagitta en

flata

Oneaea m

editerra

ea

Nannoca

lanus far

rani

Oneaea ve

nusta

Clausocal

anus farra

ni

Eusalanus s

ubtenuis

Pterosag

itta drac

o

Clausocalanus m

inor

Eusalanus

a ttenuatus

Haloptilu

s longic

orn is

Heterorhab

dus pappilig

e

Oneaea

con ifer

a

Rhinca lanus c

ornutus

Eucalanu

s crassus

Calanoids ca

rinatu

s

Abu

ndan

ce (n

o. m

-2) bacground slope seamount

21 major Zoopl. species; highest abundance was on the summit & slope

Vertical distribution of zooplankton (ind./m2) on the region of Fred Seamount(1986)

0200400600800

100012001400160018002000

Oncaea venu st

Acar tia ne gligen

Un dinula da rwin

Sagit ta en flata

Sagitta serra

to dentat

Sagitta regular i

Eupha usiacea ju

P te rosagitta drac

Lu cicutia f la

vicorni

Euca lanus subc ra ssu

Eupha usia tene r

Euca lanus a ttenu atu

S ty loch eiron carina tu

Sagit ta m inima

Neo calan us gracili

A car tia tonsa

Sagitta he xap te r

Na nnocalan us min

Oncaea conifer

Euca lanus subten ui

Oncaea med iter rane

Rh inca la nus corn utu

Ha loptilus lo

ngicorn i

Euca lanus c ra ssuA

bund

ance

(No.

m-2

)

bacground seamount

24 major species; highest abundance was in the back ground samples

Biological diversity of the seamount habitat in the Indian Ocean

0102030405060708090

100

Equ

ator

, Fre

d an

d Fa

rquh

ar

Wal

ters

Sho

als

Unkn

own

(260

)

Unk

now

n(33

6)

Unkn

own(

6631

)

Unkn

own

(549

)

Equa

tor

(01°

07'-0

1°02

' N56

°23'

-56°

43' E

)

Fred

(6.2

3 S

54.3

8 E)

Equa

tor (

0°26

' N 5

6°04

' E)

Erro

r,Equ

ator

,Fre

d,Fa

rquh

ar&

off n

orth

wes

tern

Mad

agas

car Fa

rquh

ar

Wal

ters

Sea

mou

nt

Sout

hwes

tern

Indi

an R

idge

seam

ount

s M

id-In

dian

ridg

e an

dBr

oken

ridge

sea

mou

nts

Afan

asiy

Nik

itin

Unkn

own

Seamounts

No.

of s

peci

es ProtozoansZooplanktonFishMegabenthicMacrobenthicMeiobenthicNo.of Endemic spp.

Parameiropsis sp.

Parameiropsis sp.Prionospio sp.

Hesionidae

Nematode

0

10

20

30

40

50

60

Hes

ione

sp

Prio

nosp

iosp

.

Para

done

is s

p

Nem

atod

e

Isop

oda

Tana

idac

ea

Para

mei

rops

is

Den

sity

(no.

m-2

)

Macrofaunal density & (no.m-2) diversity at unknown seamount in CIOB

Meiobenthic composition at CIOB Seamount

Nematodes 66%

Harpacticoids11%

Polychaetes6%

Nauplii6%

Halacaroidea11%

Vertical distribution of meiofauna (no.10cm-2)

0 1 2 3 4 5 6

0-0.50.5-11-1.51.5-2

2.0-4.04.0-6.06.0-8.0

8.0-10-12.0

12.0-Sedi

men

t dep

th (c

m)

Density (no.10cm-2)

Nematodes

Harpacticoids

PolychaetesNauplii

Halacaroidea

Fauna recovered in top 12 cm although core obtained up to 25 cm sed.depths.

Nematodes dominated (66%)

Desmoscolex

Sabatieria

Spiliphera

Araeolaimus

Halalaimus

Nematode genera (13) from unknown Seamount

in CIOBHalalaiusEumorpholaimusAraeolaimusLinhysteraDiplopeltulaRhabditisParaethmolaimusSabatieriaOdentophoraAxonolaimusSpilipheraUnidentified-1Unidentified-2

24%

14%0%

62%

Selective deposit feeders Non-selective deposit feeder

Epistrate feeder Predatory Omnivores

# Selective deposit feeders 62%.# No Predatory omnivores.

# High abundance and diversity in the 2-4cm depth.

# Rhabditis and Paraethmolaimus recorded only from seamount region.

Rhabditis (Head)

Rhabditis (Tail)

Octocorallia

Hexatinellidae

Pennatulacea? Station No. Phylum Class Subclass Order Family CC-2/DR-32 Porifera HexactinellidaCC-2/DR-12 Porifera HexactinellidaCC-2/ADR-33 Porifera HexactinellidaCC-1/DR-2 Arthropoda Crustacea Cirripedia Thoracica ScalpellidaeCC-1/DR-24A Cnidaria Anthozoa Zoantharia Antipatharia AntipathidaeCC-2/DR-25 Cnidaria Anthozoa Zoantharia Antipatharia AntipathidaeCC-2/DR-13 Cnidaria Anthozoa Zoantharia Antipatharia AntipathidaeCC-2/AR-11 Cnidaria AnthozoaCC-1/DR-23 Echinodermata CrinoideaCC-1/DR-23A Echinodermata CrinoideaCC-2/AR-11 Echinodermata OphiuroideaCC-2/AR-11 Cnidaria Anthozoa Octocorallia Pennatulacea?CC-1/DR-2 Unidentified

Megafauna of the Afanasiy

Nikitin seamount

Hydroid

Serpent star Ophiura sp.?Ophiura sp.?

Hyalonema spHyalonema spShrimp

Environmental Impact of deep-sea mining

Indian nodule area150,000 sq.km•2700 km away

Objectives

to assess the potential impact of nodule mining on marine ecosystem

to provide scientific inputs for design and operation of deep-sea mining system

International commitment

SCHEMATIC OF SAMPLINGIN DISTURBANCE AREA

Sedimentcores

Sediment traps

CTD & watersamples

Disturbancearea

Parameters Analysed Biology•Surface productivity•Microbiology•Biochemistry• Meiofauna• Macrofauna•Megafauna

Physics• Currents• Temperature• Conductivity• Meteorology

Chemistry• Metals

• Nutrients

• DOC

• POC

Geology•Seafloor features•Sediment thickness•Topography•Sediment sizes•Pore water and sediment chemistry•Geotechnical props.•Stratigraphy

Baseline conditionsBaseline conditionsAv. Nodule size : ~ 4 cm

Av. abundance : 1-5 kg/sq.m.

Sediment type : Clayey silt

Water content : High (300-600 %)

Sediment type : Clayey silt

Sediment flux : 7-16 g/m2/y.

Biogeochemistry : Nutrient rich

Microbial biomass : High (109g-)

Meiofauna : 07 taxa

Macrofauna : 11 taxa

Sledge mark of the disturber &sediment lumps on the side

Pre-dist. Post-dist. Mon-I Mon-II Mon-III(Jun 97) (Aug 97) (Apr 01) (Jun 02) (Apr 03)

Abund.(no.10 cm-2) 46 23 11 6 11

Groups 11 4 9 6 10Some recovery seen…..natural conditions taking over

Faint trace of disturber track with a holothurian

Holothurians were the major constituents of the megafauna (15 spp. during all three INDEX phases. A majority of the sea cucumber species are deposit feeders, can react rapidly to the fall of fresh phytodetritus arriving at the seafloorn & may recolonize the disturbed area faster compared to other spp.

DISTRIBUTION OF HARPACTICOIDA

18 genera identified; possibility of 03 new spp.

Abyssal fauna (NEW DATA)

Lat (S)

Long.(E)

DISTRIBUTION OF POLYCHAETA

20 species belonging to ten families

Lat (S)

Long.(E)

73.5 74 74.5 75 75.5 76 76.5 77

73.5 74 74.5 75 75.5 76 76.5 77

-15.5

-15

-14.5

-14

-13.5

-13

-12.5

-12

-11.5

-11

-10.5

-10

-15.5

-15

-14.5

-14

-13.5

-13

-12.5

-12

-11.5

-11

-10.5

-10

Xyalidae

Trileptium sp.Adoncholaimus sp. Cervonema sp.

Enchelidiidae Enoplid sp.

Greefilla sp.Halalaimus sp.Leptostomum sp.

Linhystera sp.

Phanodermatidae

Quadricoma sp.Spiliphara sp.

Viscosia sp.

DISTRIBUTION OF NEMATODES IN CIOB

28 genera identified; possibilities of 06 new spp.

Lat (S)

Statement of environmental impact assessment

Baseline data in proposed mining area

Criteria for selection of test and reference sites

Results of simulated impact experiment

Expected environmental impact due to mining

Parameters for monitoring impacts

Phases and milestones of the projectPhases and milestones of the project

Activity Period Remarks

• Baseline data collection 1996 - 1997 Completed • Selection of T & R sites 1997 Completed• Benthic Disturbance and 1997-2001 Completedimpact assessment

• First monitoring studies 2001-2002 Completed• Second monitoring studies 2002-2003 Completed• Third monitoring 2003-2004 Completed• Environmental variability study 2003-2005 Ongoing• Modeling of sediment plume 2003-2006 Ongoing• Creation of database 2002-2007 Ongoing_________________________________________________________

Creation of environmental databaseCreation of environmental databaseFeatures• Interactive data retrieval and comparison

• Multi-disciplinary data set

Water ColumnBenthicPhoto/Video

Applications• Ecological models

• Mining design

Proposed seamount studyBased on the detailed bathymetry, geology and geomorphology of some of the seamounts in the equatorial Indian Ocean & CIOB region as well as Arabian Sea, a multidisciplinary oceanographic survey have been proposed by NIO Goa for aiming at four EEZ (Raman, Panikkar, Wadia & Sagarkanya); few open ocean (such as Afanasiy Nikitin) seamounts in the Indian Ocean

Seamounts in the Arabian Sea

Raman

Wadia

Panikkar

The Deep Sea Drilling Project sites are located in the vicinity

Sagarkanya seamount

Some of us present here are working for a joint proposal for Indian Ocean seamount study

Acknowledgements

Thanks to all my oceanographic colleagues for their help in sample collection and processing.

COML, DARWIN (UK) CeDAMar projects for taxonomic identification & training.

ISA- for providing platform to present out data & possible int. collaboration.