distribution of freeliving marine nematodes Ann V anreusel Meioscool Brest 27 juni 2016 Introduction Their biology Their success Connectivity and distribution Cosmopolitan species ID: 1008159
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1. The connectivity and distribution of free-living marine nematodesAnn VanreuselMeioscool, Brest, 27 juni 2016
2. Introduction Their biologyTheir successConnectivity and distributionCosmopolitan speciesCryptic speciesPopulation genetics3. Environmental management context Importance of cryptic diversityConnectivity between protected areasRecolonization of disturbed areasThe connectivity and distribution of free-living marine nematodes
3. Introduction : Their biology – Life strategyLife Cycle of the nematode C. elegans www.wormatlas.org
4. Introduction : Their biology – Life strategySingh et al, 2009 40 µm150 µm800 µmHatched juvenileAdult
5. Introduction Their biology Life strategyDioecious (copulation) Oviparous (eggs in environment) Occasionnaly Ovoviviparous≠ juvenile stages (molting)(Dauer larva for some Rhabditids) )The connectivity and distribution of free-living marine nematodes
6. www.senckenberg.demacrofaunameiofauna6Introduction Their success“Meios “ intermediate to micro- and macrofaunaRetained on 38 (or 32) µm sieve Protists (forams) and metazoansAlmost exclusively associated with seafloor (s.l.) - mainly as endofauna in soft sediments - also as epifauna on ‘hard’ substrates
7. Introduction Their successMetazoan meiofauna : Nematodes dominant
8. Rex et al. (2006)Log Abundance (ind. m-²)Log Biomass (g C m-²)Introduction Their successMeiofauna increases in importance with increasing water depthWater depth
9. 9Introduction Their successOften remaining taxon in anoxic conditions
10. Normoxia Anoxia Recovery 23 days 30 daysDensitiesSpecies richnessNormoxia Anoxia Recovery 23 days 30 days
11. 100 µmHalomonhystera speciesmore than 10 000 ind/10 cm² in bacterial matsnematode densities x 10 6 per m²Depth (cm) H2S, O2 (mM)0 1 10 1000,1 0,3 0,5 0,7 0,9 1,101234Håkon Mosby Mud volcano at Barents sea slope (1280m)Van Gaever et al, 2006
12. Seamounts Cold water coralsmbariIfremerIfremerNOCIfremerNOCIfremerIfremerCold seepsCoral rubbleIfremer & AWIManganese nodulesHydrothermalventsSoft sediments :ShelfSlopeAbyssTrenchCanyonsexpected nr of genera(rarefraction)12Expected number of genera for 51 individualsVanreusel et al 2010
13. Introduction Their success(Most) abundant and species rich metazoan phylum of (deep-sea) benthosAppears in (almost) all marine sea-floor associated environmentsWide trophic range and flexibility (Moens and Vincx, 1997)
14. The connectivity and distribution of free-living marine nematodesIntroduction Connectivity and distributionCosmopolitan species
15. 2. Connectivity and distributionCosmopolitan speciesMid Atlantic ridgeAcantholaimus Lidia Lins et al in prep
16. 2. Connectivity and distributionCosmopolitan speciesThe connectivity and distribution of free-living marine nematodes60° South 10° NorthSpecies composition and diversity of Acantholaimus
17. Known global distribution of Acantholaimus species
18. 2. Connectivity and distributionCosmopolitan speciesBathymeteric distribution of Acantholaimus species
19. 2. Connectivity and distributionCosmopolitan species (molecular defined) comparison of 6 globally distributed locationsDerycke, Guillini et al, in prep
20. Introduction Connectivity and distributionCosmopolitan speciesCryptic speciesThe connectivity and distribution of free-living marine nematodes
21. Derycke et al. 2007Sympatric cryptic species complex of Halomonhystera disjuncta
22. Ovoviviparous reproduction strategyHMMV, Barents Sea, at 72°N 14°E, 1280 m Sulphide rich sediments of bacterial mats colonized by high densities ofH. disjuncta
23. Phylogenetic analysis of H. disjuncta complexITS18SrDNAHD HMMV is one of several cryptic species from a species complex known to be associatedwith degrading macroalgae on temperate mud flats (GD1-GD5) De Rycke et al 2007HD-HMMV is a seperate group but more closely related to GD1/4 than other sympatric speciesVan Campenhout et al 2014
24. Ovoviviparous reproduction strategyNew species described as H. hermesi and closely related to coastal Halomonhystera disjuncta speciesHMMV, Barents Sea, at 72°N 14°E, 1280 m Sulphide rich sediments of bacterial mats colonized by high densities ofH. disjunctaH. hermesi (Tchesunov et al, 2015)
25. Introduction Connectivity and distributionCosmopolitan speciesCryptic speciesPopulation geneticsThe connectivity and distribution of free-living marine nematodes
26. 1600 km1900 km2100 km600 km5 locations at 300-500mBox 1. Scotia Arc SG = South Georgia SO = South OrkneysBox 2. Antarctic Peninsula KG = King George IslandBox 3. Eastern Weddell Sea AUS = off Auståsen ice rise BX = Bendex (no geographic ref)~2100 km~2300 km~15 kmTwo research hypotheses: 1. strong population genetic structure between distant locations (cryptic species?) 2. surface-dwelling nematodes are more easily resuspended and transported by bottom currents than deeper-dwelling nematodes, hence will have less strong population genetic structureFreija Hauquier et al. In prep
27. 57mm30 mm20 mm‘surface’ communities food oxygenmore prone to resuspension‘subsurface’ communities less food oxygen rapidly decreasing less likely to become resuspendedDesmodoraSabatieria0 – 3 cm3 – 5 cm2 sediment slices 0 – 3cm 3 – 5cmStored on DESS2 genera selected based on general occurrence at all 5 locations Desmodora = surface-dwelling epistratum feeder Sabatieria = deeper-dwelling deposit feeder (tolerant to low O2 levels)Diversity and population genetics of two abundant genera in Southern Ocean
28. Colours = locationsHaplotype network(numbers along branches= number of base differencesNo number = only 1 difference)Surface dwelling Desmodora2 species clades based on COI species I: widely spread, yet substantial genetic differentation between populations large intraspecific phenotypic variation (2 morphospecies) species II: only at location SO (but may be sampling bias)Clade IBayesian trees of COI haplotypes for Desmodora.
29. Sabatieria 4 specieswide rangenarrow rangeSubsurface species
30. Species I Strong population genetic structure in Sabatieria species with wide distribution range (higher Φst values in AMOVA)haplotype network for ITS
31. Maria S. Merian cruise (2009)MEDECO cruise (2007)Amon MVCentral pockmark areaAmsterdam MVBrine lake CheopsMEDECO cruise (2007): Central Pockmark area (1700 m) Brine lake Cheops (3000 m) + Leopard skin pattern (3014 m) Madonna mud volcano (1650 m, Central Mediterranean area)Merian cruise (2009): Central Pockmark area (1700 m) Amon mud volcano (1150 m) Amsterdam mud volcano (2050 m)Annelies De Groote et al. Sabatieria species associated with reduced seep sediments in East Med.
32. Connectivity among isolated seeps of East Med 21 haplotypes, 6 found in multiple seeps Haplotype A: widespread in all seeps Most haplotypes: exclusively found in one seep, in very low adundances Haplotypes E - N: more mutational differences AMOVA: ST-value:15 % variability explained by differences between seeps331 ind.COIAmonCheopsA’ damPM
33. Introduction Connectivity and distributionCosmopolitan speciesCryptic speciesPopulation geneticsThe connectivity and distribution of free-living marine nematodes3. Environmental context Importance of cryptic diversity
34. Phylogenetic analysis of H. disjuncta complexITS18SrDNAHD HMMV is one of several cryptic species from a species complex known to be associatedwith degrading macroalgae on temperate mud flats (GD1-GD5) De Rycke et al 2007HD-HMMV is a seperate group but more closely related to GD1/4 than other sympatric speciesVan Campenhout et al 2014Importance of cryptic diversity
35. Life history response of GD1-3 at a salinity of 34, a temperature of 4°C and in the presence of 1mM sulphides (Na2S).Minimum generation timeEgg deposition timeEmbryonic developmentJuvenile developmentMinimum adult life spanStart (6 females, 4 males)First egg(s)First adult(s)First dead inoculated nematode17-18 days7-10 days12-17 daysEnd of experiment: F1 adults are sexually active17-18 daysFirst Juvenile(s)Van Campenhout, et al 2015Life-history response of coastal GD1-3 species to bathyal cold seep conditions
36. 3. Environmental context Importance of cryptic diversityp = 0,0001 p = 0,006 Different tolerance of cryptic species of Halomonhystera disjuncta (GD1,2 and 3) to changes in environment (sulphides, temperature and pH).Van Campenhout, et al 2015GD1 GD2GD1 GD2GD3 did not survive in the presence of sulphides. Offspring minimum adult life span
37. 3. Environmental contextImportance of cryptic diversity
38. 3. Environmental contextImportance of cryptic diversityDifferent species interactions between species in changing environmental conditionsDe Meester et al, 2011
39. Introduction Connectivity and distributionEnvironmental contextImportance of cryptic diversityConnectivity between different areasThe connectivity and distribution of free-living marine nematodes
40. www.isa.org40
41. www.isa.org41Environmental Management Plan for the Clarion Clipperton Zone 9 areas of particular environmental interest (APEI), on a provisional basis, to protect the biodiversity and ecosystem structure and functioning of the zoneAPEI = “large areas with self-sustaining populations and a broad range of habitat variability”Are APEIs effective and representative?
42. TurnoverEast West30 % species lossNo species loss≠ ≠= =
43. Introduction Connectivity and distributionEnvironmental context Importance of cryptic diversityConnectivity between different areasRecolonization of disturbed areasThe connectivity and distribution of free-living marine nematodes
44. 26 year old disturbance in nodule area1 White spot2 Crest3 Valley4 Outside track1235Mevenkamp et al
45. The connectivity and distribution of free-living marine nematodesIs the sky the limit? ‘Everything is everywhere ‘ ?Distribution through water column (?) Thank You !!!