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ANGELO FRAGA BERNARDINO

Whales, wood and kelp islands in the deep-sea: ecological

succession and species overlap with other chemosynthetic

habitats in the Californian continental slope (NE Pacific)

Tese

apresentada

ao

Instituto

Oceanográfico da Universidade de São

Paulo, como parte dos requisitos para

obtenção do título de Doutor em

Ciências,

área

de

Oceanografia

Biológica.

Orientador:

Prof. Dr. Paulo Yukio Gomes Sumida

Co-orientador:

Prof. Dr. Craig R. Smith

São Paulo

2009

Universidade de São Paulo

Instituto Oceanográfico

Whales, wood and kelp islands in the deep-sea: ecological succession and species

overlap with other chemosynthetic habitats in the Californian continental slope (NE

Pacific)

Angelo Fraga Bernardino

Tese apresentada ao Instituto Oceanográfico da Universidade de São Paulo, como

parte dos requisitos para obtenção do título de Doutor em Ciências, área de

Oceanografia Biológica.

Julgada em ___/___/_____

Prof.(a) Dr.(a)

Conceito

Prof.(a) Dr.(a)

Conceito

Prof.(a) Dr.(a)

Conceito

Prof.(a) Dr.(a)

Conceito

Prof.(a) Dr.(a)

Conceito

i

INDEX

List of Tables ……………………………………………………………….…………

ii

List of Figures ………………………………………………………………..……….

iii

Abstract ………………………………………………………………..………………

v

Resumo ………………………………………………………………..………………

vi

Chapter 1. Introduction ………………………………………………….……………..

1

1.1. References ..………………………..….………………………………..…........

6

Chapter 2. Macrofaunal succession in sediments around kelp and wood falls in the

9

deep NE Pacific and community overlap with other reducing habitats

2.1. Introduction ……………………………………………………………………. 10

2.2. Materials and methods ……………...........…………………………………….. 12

2.3. Results ………………………... .......................................................................... 19

2.4. Discussion …………………………….………………………………………..

38

2.5. Conclusions …………….……………………………………………………… 46

2.6. References ……….…………………………………………………………….. 46

2.7. Supplementary material …………………………….………………………….

55

Chapter 3. Infaunal community structure and succession during the sulfophilic stage 57

of a whale carcass in the deep NE Pacific

3.1. Introduction ……………………………….…………………………………… 58

3.2. Material and methods ……………………..…………………………………… 62

3.3. Results ………………………………….……………………………………… 68

3.4. Discussion ……………………………………………………………………...

88

3.5. Conclusions ……………………………………………….…………………...

97

3.6. References ……………………………………………………………………..

98

Chapter 4. The San Clemente cold seep: macrofaunal structure and species overlap 109

with reducing habitats in the deep NE Pacific

4.1. Introduction …………………………………………….……………………… 110

ii

4.2 Study site and methods ………………………..………………..……………..

113

4.3 Results …………………..……………………………………..……………… 117

4.4 Discusion ……………………………...……………………….………………. 124

4.5 References ……………………………................................…………..……… 132

Chapter 5. Conclusions ………………………………................................................ 141

LIST OF TABLES

Table 2.1 ……………………………….……………………………………...............

14

Table 2.2 …………………………………………………………………...……..…...

23

Table 2.3 …………………...……..…..…………………...……..……………………

24

Table 2.4 ..…………………………………….............................................................

28

Table 2.5 ……………………………………………...................................................

29

Table 2.6 …………………………………………………………………...................

33

Table 2.7 ……………………………………………………………...........................

38

Appendix 2A ………………………………………………………............................

52

Appendix 2B …………………………………………………………………………

53

Table S2.1 …………………………………………………………............................

56

Table 3.1 ……………………………………………………………………………..

70

Table 3.2 …………….................................................................................................

73

Table 3.3 …………………………………………………………………………….

79

iii

Table 3.4 …………………………………………………………………………….

80

Table 3.5 …………………………………………………………………………….

84

Table 3.6 …………………………………………………………………………….

86

Appendix 3A. ……......................................................................................................

105

Appendix 3B ……………………………...................................................................

106

Table 4.1 …………………………………………………………………………….

114

Table 4.2 …………………………………………………………………………….

119

Table 4.3 …………………………………………………………………………….

120

Table 4.4 …………………………………………………………………………….

130

Appendix 4.A ……………………………………………………………………….

137

LIST OF FIGURES

Figure 1.1 ………………………………………...................................................

5

Figure 2.1 ...............................................................................................................

13

Figure 2.2. …………………………......................................................................

20

Figure 2.3. ……………………………....................................................................

22

Figure 2.4. …………….……..….…………………...……..…...............................

23

Figure 2.5. ………………………………………………………………………....

24

Figure 2.6 …..............................................................................................................

25

Figure 2.7 ..................................................................................................................

27

Figure 2.8 ..................................................................................................................

28

iv

Figure 2.9 ……………………………………...........................................................

29

Figure 2.10 ………………………………….............................................................

30

Figure 2.11 ………………………………….............................................................

31

Figure 2.12 ………….................................................................................................

34

Figure S2.1. ……........................................................................................................

55

Figure 3.1 ……….......................................................................................................

69

Figure 3.2 ……….......................................................................................................

70

Figure 3.3 ……….......................................................................................................

72

Figure 3.4 ………………………………………………............................................

74

Figure 3.5 …………………………………………...................................................

76

Figure 3.6 ………………………………………………………...............................

77

Figure 3.7 …………………………............................................................................

78

Figure 3.8 ………………………................................................................................

81

Figure 3.9 ....................................................................................................................

82

Figure 3.10 ..................................................................................................................

85

Figure 4.1 ……............................................................................................................

114

Figure 4.2 ……............................................................................................................

118

Figure 4.3 ……............................................................................................................

119

Figure 4.4 ……............................................................................................................

121

Figure 4.5 ……............................................................................................................

122

Figure 4.6 ……............................................................................................................

124

v

Abstract

Sunken parcels of macroalgae, wood and whale carcasses provide important oases

of organic enrichment at the deep-sea floor, but sediment community structure and

succession around these habitat islands are poorly evaluated. We experimentally

implanted parcels of kelp and wood falls nearby a 30-ton deep-sea whale-fall at 1670 m

in the Santa Cruz Basin (SCr; NE Pacific). At each organic island, we aimed to evaluate

patterns of organic enrichment and spatial and temporal patterns of macrofaunal

community structure and succession over time scales of 0.25 to 7y. Additionally, species

overlap between kelp-, wood- and whale-falls with nearby cold-seep communities were

investigated. In general, the abundance of infaunal macrobenthos was highly elevated at

periods of intense organic enrichment at all organic falls, with decreased macrofaunal

diversity and evenness within 0.5 meters of the falls. At kelp and wood falls opportunistic

species and sulfide tolerant microbial grazers (dorvilleid polychaetes) abounded after the

peak of sedimentary enrichment (0.25y and 1.8y, respectively), while the whale-fall

macrofauna was highly abundant from 4.5 to 6.8 y, and was dominated by enrichment

opportunist, chemoautotrophic-symbiont-hosting and heterotrophic species grazing

sulfur-oxidizing bacterial mats. Sediments around kelp and wood parcels provided low-

intensity reducing conditions, which sustain a limited chemoautotrophically-based fauna,

with low levels of species overlap among other chemosynthetic habitats in the deep NE

Pacific. Whale-fall sediments harbor many species and trophic types not present in

background sediments, but there were low levels of species overlap between the whale-

fall, cold seeps and hydrothermal vents, explained by differences in biogeochemistry and

food webs among these habitats. We conclude that organically enriched sediments around

kelp, wood and whale-falls may provide important habitat islands for the persistence and

evolution of species dependent on organic- and sulfide-rich conditions at the deep-sea

floor and contribute to regional and global diversity in deep-sea ecosystems.

vi

Resumo

Parcelas orgânicas de macroalgas, madeira e carcaças de baleia criam importantes

oasis de enriquecimento orgânico no assoalho marinho de regiões profundas, mas a

estrutura e sucessão ecológica da macrofauna sedimentar ao redor destes ambientes ainda

é pouco conhecida. Parcelas de macroalgas e madeira foram artificialmente implantadas

próximas a uma carcaça de baleia de 30-ton hà uma profundidade de 1670 m na Bacia de

Santa Cruz, Pacífico NE. Ao redor de cada ilha orgânica, foram estudados os padrões

espaciais e temporais de enriquecimento sedimentar orgânico e a estrutura e sucessão

temporal da macrofauna em escalas temporais que variam de 0.25 à 7 anos. Ainda, o

nível de sobreposição entre espécies colonizadoras das parcelas orgânicas e na baleia,

foram comparados com comunidades de exudações frias (uma localizada na bacia de São

Clemente, Pacífico NE) e fontes hidrotermais. Em geral, a abundância da macrofauna

sedimentar foi altamente elevada em períodos de intenso enriquecimento orgânico, com

decréscimo da diversidade da macrofauna num raio de 0.5 metros das parcelas. Nas

parcelas de macroalgas e madeira, espécies oportunistas e tolerantes à sulfetos atingiram

altas densidades após o pico de enriquecimento orgânico sedimentar (0.25 e 1.8 anos,

respectivamente), enquanto que ao redor da carcaça de baleia, a macrofauna foi também

dominada por organismos quimiossintéticos com associações simbióticas bacterianas, e

ainda espécies oportunistas que se alimentavam do abundante carpete bacteriano sobre a

superfície sedimentar. Os sedimentos ao redor das parcelas de macroalgas e madeira

sustentam baixas taxas de degradação microbiana e sulfeto intersticial, recrutando assim

um limitado número de organismos quimioautotróficos e consequentemente com baixa

sobreposição de espécies com outros ambientes redutores. Na carcaça de baleia, os

sedimentos sustentam intensa degradação microbiana e altos níveis de sulfeto, mas

diferenças marcantes nas biogeoquímica e nas cadeias tróficas presentes nestas carcaças

resultam em baixa sobreposição de espécies com a fauna de exsudações frias e fontes

hidrotermais. Conclui-se que sedimentos enriquecidos organicamente ao redor de

macroalgas, madeiras e carcaças de baleia criam importantes hábitats para a persistência

e evolução de espécies dependentes de condições sedimentares redutoras, e assim estas

ilhas devem contribuir para a diversidade regional e global dos ecossistemas de mar

profundo.

1

Chapter 1. Introduction

Communities living at the deep-seafloor are directly affected the export of

organic matter from the ocean’s surface to depths, which significantly affects the

structure and dynamics of deep-sea benthic ecosystems (Gage & Tyler 1991, Smith et

al. 2008). Some special exceptions are found at cold seeps and hydrothermal vents,

where chemosynthesis is a major process fueling local communities (Tunnicliffe

1988, Levin 2005). Therefore, the typical deep-sea benthos are dependent on a low

flux rate of organic matter (e.g. phytoplankton detritus), which is partially decayed

during its long and sluggish sink the deep-sea floor (Gage & Tyler 1991). However,

the export of food to the sea bottom does not always occur at a slow pace and in some

regions of the world’s oceans, seasonal bursts in primary production give rise to

massive exports of particulate organic material that settles rapidly to the sea bottom

(Billett et al. 1983, Beaulieu 2002).

Although settling of pelagic organic matter may largely contribute to the bulk

of energy that is available to deep-sea ecosystems, the massive episodic deliveries of

labile organic carbon to these ecosystems are also important (Stockton & DeLaca

1982, Smith 1985, Rice & Lambshead 1994). Macroalgae, terrestrial plants debris,

and carcasses of pelagic animals occur at variable temporal and spatial scales

(Stockton & DeLaca 1982, Grassle & Morse-Porteous 1987). Woody and macroalgal

debris are frequently deposited on continental slopes through physical or biological

processes. Kelps can be released from the coastal zone during storms, high swell

events, and from herbivory (Duggins et al. 1989, Harrold et al. 1998). Kelp and wood

debris can then be concentrated and transported to depths in submarine canyons to

form enormous accumulations of organic material in the deep ocean (Vetter 1994,

2

Vetter & Dayton 1998, 1999, McLeod & Wing 2007). Wood and kelp parcels also

float out to sea, sinking as individual parcels spanning a broad range of sizes (1 -

>200 kg) to the seafloor (Wolff 1979). Carcasses of nektonic animals ( e.g. fishes,

dolphins and whales) are additional sources of energy to the deep sea as they provide

fresh organic material into a food-poor environment (Stockton & DeLaca 1982, Smith

1985, 1986, Smith & Demopoulos 2005). Although the flux of whale-detritus is not as

quantitatively significant as the total particulate organic carbon (POC) flux to deep-

sea oceans, dead whales sink as enormous organic-rich packages that disturb a very

limited area of the sea-bottom (Smith 2006). For example, the seabed immediately

underlying a typical whale fall (i.e. roughly 50 m2), can experience the equivalent of

2000 yr of background POC flux in a single pulse of organic enrichment (Smith &

Baco 2003). Consequently, whale carcasses provide an immense and very rich source

of labile organic matter to the food limited deep-sea ecosystems.

Organic falls are important sources of disturbance to benthic communities

nearby continental margins and in the deep-sea (Stockton & DeLaca 1982, Smith

1985, 1986, Smith et al. 1998). As the scavenging and decaying of the organic falls

take place, organic detritus [i.e. particulate organic carbon (POC)] is released into the

surrounding sediments providing food for the infauna (Turner 1977, Wolff 1979,

Stockton & DeLaca 1982, Grassle & Morse-Porteous 1987). The spatial succession

along organic-enrichment gradients exhibits very low diversity and extremely high

densities of “opportunistic” species in disturbed areas, with moderate macrofaunal

enhancement and species diversity at intermediate distances, and very low

abundances and high diversity in the background community (Pearson & Rosenberg

1978, Smith et al. 2002, Smith & Baco 2003). Consequently, the type and the

magnitude of the organic enrichment will create distinct responses by the benthic

3

fauna. The organic enrichment attracts organisms through both numerical (e.g.,

reproduction of opportunistic species) and functional responses (e.g., omnivores and

scavengers), thus modifying the structure of natural deep-sea communities (Grassle &

Grassle 1974, Pearson & Rosenberg 1978). High levels of organic disturbance may

additionally promote intense microbial decomposition, depletion of pore-water

oxygen and increase levels of sulfides in the sediments (Boetius & Lochte 1996,

Smith & Baco 2003, Treude et al. 2003). Reducing sediments around organic islands

attracts sulfophilic organisms that are capable of deriving carbon from

chemosynthetic symbiosis and are adapted to survive in low oxygen sediments (Fisher

1999, Dubilier et al. 2008).

Whale skeletons generate and sustain organic-rich conditions for years in the

deep-sea. The broad range of ecological niches present at whale carcasses attracts

organisms not found on background areas, including whale-fall “specialists” and

heterotrophic opportunists (Baco-Taylor & Smith 2003, Smith & Baco 2003). The

creation of hard substrata for marine invertebrates also attracts dense assemblages of

megafaunal animals, including fish and invertebrates (Vetter & Dayton 1998, 1999).

Wood and kelp falls also attract their own set of specialists, including wood-boring

bivalves which degrade the wood matrix as they grow (Turner 1973). Consequently,

organic patches open new areas for colonization of rare, opportunistic and specialist

species, and have the potential to increase species richness locally. The role of organic

patches in increasing deep-sea diversity has been raised decades ago, but studies well

designed to address this hypothesis are scarce (Snelgrove & Smith 2002). The

comparison of community structure and succession at distinct food parcels can help

elucidate the contribution of organic falls for beta diversity (i.e. regional scale) in the

deep sea. The long-term comparisons of community structure also allow identifying

4

levels of species overlap among distinct types organic and sulfide enrichments, such

as around whale-, wood- and kelp falls and cold seeps.

The present study will look at community structure and succession at

artificially deployed parcels of wood, kelp ( Macrocystis pyrifera) and a large whale-

fall; and also investigate the San Clemente cold-seep macrofauna, which are all at

similar depths on the California continental slope (Figure 1.1). This study will focus

at the sediment macrofauna at each site and patterns of sediment organic and sulfide

enrichment will be used to help explain ecological patterns at spatial and temporal

scales. Through the comparison and characterization of community structure and

succession at a variety of reducing habitats and organic islands on the southern

California slope (cold seeps, whale-, kelp- and wood-falls) we expect to test the

following general hypothesis:

i) Kelp, wood, and whale falls produce highly distinct time courses of

sediment organic loading, which create distinct patterns of community succession;

ii) Kelp- and wood-fall communities are less diverse than background

sediments and host a smaller set of specialized fauna compared to whale-fall

communities;

iii) Whale-fall sediment communities increase local species diversity but share

a small proportion (<20%) of species with assemblages at southern California seeps,

kelp falls and wood falls at similar ocean depths.

iv) The San Clemente seep macrofaunal sediment community contains few

specialized species, and exhibits similar levels of diversity to background sediments;

index-13_1.png

5

Figure 1.1. Map from the Southern California coast (USA) showing the position of known

whale carcasses and San Clemente cold seep (isobaths in meters) A: Deployment site of kelp

and wood parcels, and of a whale carcass implanted in 1998; B: Natural whale carcass found

at Santa Catalina Basin by C. Smith in 1987; C: Small (5.000-kg) whale carcass artificially

implanted at San Diego Through in 1996; D: San Clemente cold seep.

6

1.1. References

Baco-Taylor A, Smith CR (2003) High species richness in deep-sea chemoautotrophic

whale skeleton communities. Marine Ecology Progress Series 260:109-114

Beaulieu SE (2002) Accumulation and fate of phytodetritus on the sea floor.

Oceanography and Marine Biology: an Annual Review 40:171-232

Billett DSM, Lampitt RS, Rice AL, Mantoura RFC (1983) Seasonal sedimentation of

phytoplankton to the deep-sea benthos. Nature 302:520-522

Boetius A, Lochte K (1996) Effect of organic enrichments on hydrolytic potentials

and growth of bacteria in deep-sea sediments. Marine Ecology Progress Series

140:239-250

Dubilier N, Bergin C, Lott C (2008) Symbiotic diversity in marine animals: the art of

harnessing chemosynthesis. Nature Reviews: Microbiology 6:725-740

Duggins DO, Simenstad CA, Estes JA (1989) Magnification of secondary production

by Kelp detritus in coastal marine ecosystems. Science 245:170-172

Fisher CR (1999) Chemoautotrophic and methanotrophic symbioses in marine

invertebrates. Reviews in Aquatic Sciences 2:399-436

Gage JD, Tyler PA (1991) Deep-Sea Biology: a natural history of organisms at the

deep-sea floor, Vol. Cambridge University Press, Cambridge

Grassle JF, Grassle JP (1974) Opportunistic life histories and genetic systems in

marine benthic polychaetes. Journal of Marine Research 32:253

Grassle JF, Morse-Porteous LS (1987) Macrofaunal utilization of disturbed deep-sea

environments and the structure of deep-sea benthic communities. Deep-Sea

Research 34:1911-1950

Harrold C, Light K, Lisin S (1998) Organic enrichment of submarine-canyon and

continental-shelf benthic communities by macroalgal drift imported from

nearshore kelp forests. Limnology and Oceanography 43:669-678

Levin LA (2005) Ecology of cold seep sediments: interactions of fauna with flow,

chemistry and microbes. Oceanography and Marine Biology: an Annual

Review 43:1-46

McLeod RJ, Wing SR (2007) Hagfish in the New Zealand fjords are supported by

chemoautotrophy of forest carbon. Ecology 88:809-816

7

Pearson TH, Rosenberg R (1978) Macrobenthic succession in relation to organic

enrichment and pollution in the marine environment. Oceanography and

Marine Biology an Annual Review 16:229-311

Rice AL, Lambshead PJD (1994) Patch dynamics in the deep-sea benthos: the role of

a heterogeneous supply of organic matter. In: Giller PS, Hildrew AG, Raffaelli

DG (eds) Aquatic Ecology: Scale, pattern and process. Blackwell Scientific,

Oxford, p 469-497

Smith CR (1985) Food for the deep-sea: utilization, dispersion and flux of nekton

falls at the Santa Catalina Basin floor. Deep-Sea Research 32:417-442

Smith CR (1986) Nekton falls, low-intensity disturbance and community structure of

infaunal benthos in the deep-sea. Journal of Marine Research 44:567-600

Smith CR (2006) Bigger is better: The roles of whales as detritus in marine

ecosystems. In: Estes J (ed) Whales, Whaling and Marine Ecosystems.

University of California, California

Smith CR, Baco A (2003) Ecology of whale falls at the deep-sea floor. Oceanography

and Marine Biology: an Annual Review 41:311-354

Smith CR, Baco-Taylor AR, Glover AG (2002) Faunal succession on replicate deep-

sea whale falls: time scales and vent-seep affinities. Cahiers de Biologie

Marine 43:293-297

Smith CR, De Leo FC, Bernardino A, Sweetman AK, Arbizu PM (2008) Abyssal

food limitation, ecosystem structure and climate change. Trends in ecology

and evolution 23:518-528

Smith CR, Demopoulos AWJ (2005) The deep Pacific ocean floor. In: Ecossystems

of the World, Vol 27

Smith CR, Maybaum HL, Baco-Taylor A, Pope RH, Carpenter SD, Yager PL, Macko

SA, Deming JW (1998) Sediment community structure around a whale

skeleton in the deep Northeast Pacific: macrofaunal, microbial and

bioturbation effects. Deep-Sea Research II 45:335-364

Snelgrove PVR, Smith CR (2002) A riot of species in an environmental calm: the

paradox of the species-rich deep-sea floor. Oceanography and Marine

Biology: an Annual Review 40:311-342

Stockton WL, DeLaca TE (1982) Food falls in the deep sea: ocurrence, quality and

significance. Deep-Sea Research 29:157-169

8

Treude T, Boetius A, Knittel K, Wallmann K, Jorgensen BB (2003) Anaerobic

oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean.

Marine Ecology Progress Series 264:1-14

Tunnicliffe V (1988) Biogeography and evolution of hydrotermal-vent fauna in the

Eastern Pacific ocean. Proceedings of the Royal Society of London Series B

233:347-366

Turner RD (1973) Wood-boring bivalves, opportunistic species in the deep-sea.

Science 180:1377-1379

Turner RD (1977) Wood, mollusks, and deep-sea food chains. Bulletin of the

American Malacological Union 1976:13-19

Vetter EW (1994) Hotspots of benthic production. Nature 372:47

Vetter EW, Dayton PK (1998) Macrofaunal communities within and adjacent to a

detritus-rich submarine canyon system. Deep-Sea Research II 45:25-54

Vetter EW, Dayton PK (1999) Organic enrichment by macrophyte detritus and

abundance patterns of megafaunal populations in submarine canyons. Marine

Ecology Progress Series 186:137-148

Wolff T (1979) Macrofaunal utilization of plant remains in the deep sea. Sarsia

64:117-136

9

Chapter 2. Macrofaunal succession in sediments around kelp

and wood falls in the deep NE Pacific and community overlap

with other reducing habitats

Abstract

Sunken parcels of macroalgae and wood provide important oases of organic

enrichment at the deep-sea floor, yet sediment community structure and succession

around these habitat islands are poorly evaluated. We experimentally implanted 100-

kg kelp falls and 200 kg wood falls at 1670 m depth in the Santa Cruz Basin to

investigate (1) macrofaunal succession, and (2) species overlap with nearby whale-fall

and cold-seep communities over time scales of 0.25 to 5.5 y. The abundance of

infaunal macrobenthos was highly elevated after 0.25 and 0.5 y near kelp parcels with

decreased macrofaunal diversity and evenness within 0.5 meters of the falls.

Apparently opportunistic species (e.g., two new species of cumaceans) and sulfide

tolerant microbial grazers (dorvilleid polychaetes) abounded after 0.25 -0.5 y. At

wood falls, opportunistic cumaceans become abundant after 0.5 y, but sulfide tolerant

species only became abundant after 1.8 - 5.5 y, in accordance with the much slower

buildup of porewater sulfides at wood parcels compared to kelp falls. Species

diversity decreased significantly over time in sediments adjacent to the wood parcels,

most likely due to stress resulting from intense organic loading of nearby sediments

(up to 20-30% organic carbon). Dorvilleid and ampharetid polychaetes were among

the top-ranked fauna at wood parcels after 3.0 - 5.5 y. Sediments around kelp and

wood parcels provided low-intensity reducing conditions, which sustain a limited

chemoautrotrophically-based fauna. As a result, macrobenthic species overlap among

kelp, wood, and other chemosynthetic habitats in the deep NE Pacific are primarily

restricted to apparently sulfide tolerant species such as dorvilleid polychaetes,

opportunistic cumaceans, and juvenile stages of chemosymbiont containing

vesicomyid bivalves. We conclude that organically enriched sediments around wood

falls may provide important habitat islands for the persistence and evolution of

10

species dependent on organic- and sulfide-rich conditions at the deep-sea floor and

contribute to β and γ diversity in deep-sea ecosystems.

2.1. Introduction

Plant remains such as wood and macroalgal debris have long been known

from the deep-sea floor and the fossil record, with first reports dating from The

Challenger expedition (Wolff 1979, Kiel & Goedert 2006). Deep-sea imaging and

trawl studies suggest that wood and macroalgal falls occur widely on the ocean floor

(Wolff 1979, Pailleret et al. 2007). Woody and macroalgal debris are frequently

deposited on continental slopes through physical or biological processes. For

example, kelp is released from the coastal zone during storms, high swell events, and

from herbivory (Duggins et al. 1989). Kelp and wood debris can be concentrated and

transported to depths in submarine canyons to form enormous accumulations of

organic material in the deep ocean (Vetter 1994, Vetter & Dayton 1998, 1999,

McLeod & Wing 2007). Wood and kelp parcels also float out to sea, sinking as