Bryozoans As Palaeoenvironmental Indicators Paul D Taylor, NHM, London
Bryozoans as palaeoenvironmental indicators Paul D Taylor, NHM, London
Friday, 7 October 2011 What are bryozoans?
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth • suspension feeders
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth • suspension feeders • all colonial
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth • suspension feeders • all colonial • usually sessile, benthic
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth • suspension feeders • all colonial • usually sessile, benthic
• most have CaCO3 skeletons
Friday, 7 October 2011 What are bryozoans?
• invertebrate phylum • >6000 living species • mainly marine • intertidal to 8000 m depth • suspension feeders • all colonial • usually sessile, benthic
• most have CaCO3 skeletons
• Ordovician-Recent
Friday, 7 October 2011 Bryozoan colony-forms
Friday, 7 October 2011 Robert Hooke’s illustration of Flustra from Micrographia (1665)
Friday, 7 October 2011 Friday, 7 October 2011 Friday, 7 October 2011 125 Phanerozoic bryozoan family diversity
100
75
families
50 cheilostomes
25
0 500 400 300 200 100 0 Ma ORDOVICIAN PRESENT DAY
Friday, 7 October 2011 125 Phanerozoic bryozoan family diversity
100
Ordovician radiation
75
families
50 cheilostomes
25
0 500 400 300 200 100 0 Ma ORDOVICIAN PRESENT DAY
Friday, 7 October 2011 125 Phanerozoic bryozoan family diversity
100
Ordovician radiation Permian extinction
75
families
50 cheilostomes
25
0 500 400 300 200 100 0 Ma ORDOVICIAN PRESENT DAY
Friday, 7 October 2011 125 Phanerozoic bryozoan family diversity
100
Ordovician radiation Permian extinction
75 Cretaceous
families radiation
50 cheilostomes
25
0 500 400 300 200 100 0 Ma ORDOVICIAN PRESENT DAY
Friday, 7 October 2011 Abundant
Upper Ordovician Cincinnati, USA rock-forming
Friday, 7 October 2011 Abundant Diverse
Upper Ordovician Upper Cretaceous Cincinnati, USA Maastricht, Netherlands
rock-forming > 600 bryozoan species
Friday, 7 October 2011 Bryozoans as palaeoenvironmental indicators
1. modern environments with bryozoans
2. colony-form analysis
3. branch diameter as a depth indicator
4. zooid size as a temperature indicator
5. palaeolatitudinal distribution of bryozoan carbonates through time
[skeletal geochemistry] Akkeshi Bay Japan
Friday, 7 October 2011 1. modern environments with bryozoans
Friday, 7 October 2011 Modern environments colonized by bryozoans
Friday, 7 October 2011 Modern environments colonized by bryozoans
Freshwater bryozoans Low diversity Unmineralized
Friday, 7 October 2011 Modern environments colonized by bryozoans
Freshwater bryozoans Brackish bryozoans Low diversity Low diversity Unmineralized Weakly mineralized
Friday, 7 October 2011 Modern environments colonized by bryozoans
Freshwater bryozoans Brackish bryozoans Low diversity Low diversity Unmineralized Weakly mineralized
Deep sea bryozoans Moderate diversity Weakly mineralized Friday, 7 October 2011 Modern environments colonized by bryozoans
Freshwater bryozoans Brackish bryozoans Low diversity Low diversity Unmineralized Weakly mineralized
Shelf bryozoans Deep sea bryozoans High diversity Moderate diversity Most species well-mineralized Weakly mineralized Friday, 7 October 2011 Recent bryozoan species diversity increasing with depth English Channel (Grant & Hayward 1985)
Friday, 7 October 2011 Bryozoan assemblage species richness vs depth in the eastern (black dots) and western (white dots) North Atlantic
10 m 75 m
Clarke & Lidgard 2000. Journal of Animal Ecology 69: 799-814 Friday, 7 October 2011 2. colony-form analysis
Friday, 7 October 2011 Encrus ng: Porella
Friday, 7 October 2011 Dome shaped: 'Dianulites' Encrus ng: Porella
Friday, 7 October 2011 Dome shaped: 'Dianulites' Encrus ng: Porella
Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites' Encrus ng: Porella
Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites' Encrus ng: Porella
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites'
Encrus ng: Porella Foliose: Pentapora
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites'
Encrus ng: Porella Foliose: Pentapora Fenestrate: Chasmatopora
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites'
Encrus ng: Porella Foliose: Pentapora Fenestrate: Chasmatopora
Ar culated: Cellaria
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Dome shaped: 'Dianulites'
Encrus ng: Porella Foliose: Pentapora Fenestrate: Chasmatopora
Ar culated: Cellaria Free-living: Cupuladria
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Cheilostome bryozoan colony-forms (from Moissette 2000)
can these colony-forms be used as environmental indicators?
Friday, 7 October 2011 Cheilostome bryozoan colony-forms (from Moissette 2000)
deep water
strong currents shallow water
high sedimentation can these colony-forms be used as environmental indicators?
Friday, 7 October 2011 Sea-bed topography around New Zealand
Otago Shelf
Friday, 7 October 2011 bryozoan meadow, 100 metres Otago Shelf, New Zealand
sediment from bryozoan meadow
Friday, 7 October 2011 Different colony-forms represent alternative functional adaptive strategies Encrus ng colonies
Multiserial sheet
Uniserial runner
Friday, 7 October 2011 37 zooid encrusting colonies on substrates divided into equal-sized squares
sheet runner
Friday, 7 October 2011 37 zooid encrusting colonies on substrates divided into equal-sized squares
sheet runner Runner ‘samples’ more squares of substrate and spreads a greater distance from origin (fugitive strategy)
Friday, 7 October 2011 37 zooid encrusting colonies on substrates divided into equal-sized squares
sheet runner Runner ‘samples’ more Sheet is compact and better squares of substrate and able to defend space spreads a greater distance (‘confrontational strategy’) from origin (fugitive strategy)
Friday, 7 October 2011 Percentage of SHALLOW DEEP (> 50 m) colony-forms in bryozoan assemblages from shallow and deep 14% 21% stations in Spitsbergen
74% Uniserial 77% Multiserial encrusters encrusters
?reflecting decreasing food resources with depth
Friday, 7 October 2011 Fenestrate colonies Cheilostome 'Sertella' (reteporiform) (Oligocene, Argen na)
• 'traditionally' regarded as adaptation to strong currents
• but colonies can be found in slow flow regimes too (e.g. caves) Chasmatopora (Ordovician, Estonia)
Friday, 7 October 2011 Ar culated colonies Cheilostome Cellaria (Recent, Croa a) (cellariiform)
• elastic nodes allow flexure in strong currents
• but colonies also found in areas of relatively high sedimentation and weak currents – sediment can be shaken off branches Crisia (Recent, Brazil)
Friday, 7 October 2011 Free living colonies (lunuli form)
Cupuladria Cupuladria (Pliocene, England) (Miocene, France)
• able to live on fine sediments (fine sand, silt and mud) where no large substrates are present
• colonies can dig themselves out if buried
Friday, 7 October 2011 adapted for living on fine-grained, unstable substrates
Friday, 7 October 2011 Dome shaped: 'Dianulites' Encrus ng: Porella Foliose: Pentapora Fenestrate: Chasmatopora
Ar culated: Cellaria Free-living: Cupuladria
Palmate: Phaenopora Robust branched: Heteropora Narrow branched: Arcanopora Friday, 7 October 2011 Changing proportion of bryozoan colony-forms through time
ORD SIL DEV CARB PERM TRI JUR CRET PG NG
Friday, 7 October 2011 Using bryozoan colony-form in palaeoenvironmental reconstruction must be approached with caution
Friday, 7 October 2011 Using bryozoan colony-form in palaeoenvironmental reconstruction must be approached with caution
• particular colony-forms are seldom if ever restricted to one environment; sometimes almost all major colony-forms can be found together
Friday, 7 October 2011 Using bryozoan colony-form in palaeoenvironmental reconstruction must be approached with caution
• particular colony-forms are seldom if ever restricted to one environment; sometimes almost all major colony-forms can be found together
• not enough known about factors controlling colony-forms in modern environments
Friday, 7 October 2011 Using bryozoan colony-form in palaeoenvironmental reconstruction must be approached with caution
• particular colony-forms are seldom if ever restricted to one environment; sometimes almost all major colony-forms can be found together
• not enough known about factors controlling colony-forms in modern environments
• colony-forms represent alternative functional adaptive strategies that may be viable in many different environments
Friday, 7 October 2011 Using bryozoan colony-form in palaeoenvironmental reconstruction must be approached with caution
• particular colony-forms are seldom if ever restricted to one environment; sometimes almost all major colony-forms can be found together
• not enough known about factors controlling colony-forms in modern environments
• colony-forms represent alternative functional adaptive strategies that may be viable in many different environments
• representation of different colony forms has changed through the Phanerozoic
Friday, 7 October 2011 3. branch diameter as a depth indicator
Friday, 7 October 2011 Branch diameter variation within coral species as depth indicator
shallow site
intermediate site
Coral
Pocillopora damicornis (see Kaandorp 1999)
deep site
Friday, 7 October 2011 Branching bryozoans (ramose, dendroid)
Diaperoecia. Recent
Pleistocene. Setana Fm Kuromatsunai, Japan
Friday, 7 October 2011 Heteropora pacifica Puget Sound, USA (Schopf et al. 1980)
Friday, 7 October 2011 three cyclostome species:
Cinctipora elegans Diaperoecia purpurascens Erksonea sp.
Taylor, Kuklinski & Gordon (2007)
Friday, 7 October 2011 Branch diameter does correlate with depth
r = -0.37, p <0.001 branch diameter (mm) diameter branch
depth (metres) Error bars = 2 SD Friday, 7 October 2011 Branch diameter does not correlate with depth
r = -0.13, p = 0.166 branch diameter (mm) diameter branch
depth (metres) Error bars = 2 SD Friday, 7 October 2011 Branch diameter does not correlate with depth
r = -0.10, p = 0.320 branch diameter (mm) diameter branch
depth (metres) Error bars = 2 SD Friday, 7 October 2011 4. zooid size as a temperature indicator
Friday, 7 October 2011 Cheilostome bryozoan zooid size is inversely correlated with ambient temperature at time of budding 700
650
cheilostome bryozoan 600 Electra pilosa
550 zooid length (microns) length zooid
500
6°C cultivation12°C temperature18°C 22°C
Friday, 7 October 2011 Cupuladria exfragminis
upwelling (cold) zooids non-upwelling (warm) zooids
Okamura et al. 2011 Friday, 7 October 2011 Cribrilina cryptooecium
Cold Recent British
Large zooids
Warm Coralline Crag (Pliocene)
Small zooids
Friday, 7 October 2011 MART analysis using within-colony variation in zooid size
MART = mean annual range in temperature
Aaron O’Dea
Friday, 7 October 2011 Conopeum seurati Avonmouth, England
Friday, 7 October 2011 Conopeum seurati Avonmouth, England
summer zooids
Friday, 7 October 2011 Conopeum seurati Avonmouth, England
summer zooids winter zooids
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 size zooid seawater temperature
summer winter summer
Friday, 7 October 2011 seasonal climate high variance in zooid size size zooid
Friday, 7 October 2011 seasonal climate high variance in zooid size size zooid
constant temperature no variance
size in zooid size zooid
Friday, 7 October 2011 MART method
Friday, 7 October 2011 MART method • randomly select 20 zooids
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
• measure zooid length and width
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
• measure zooid length and width
• calculate length x width (= area proxy)
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
• measure zooid length and width
• calculate length x width (= area proxy)
• calculate CV (= SD/mean x 100)
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
• measure zooid length and width
• calculate length x width (= area proxy)
• calculate CV (= SD/mean x 100)
• repeat in at least 4 more colonies
Friday, 7 October 2011 MART method • randomly select 20 zooids
• avoid early zooids and areas of irregular growth
• measure zooid length and width
• calculate length x width (= area proxy)
• calculate CV (= SD/mean x 100)
• repeat in at least 4 more colonies
Friday,• 7apply October 2011 MART equation 29 Recent cheilostome species
MART = -3+0.745(b)
where (b) is the mean intracolony CV of frontal area (length x width)
Friday, 7 October 2011 Contrasting seasonality between Caribbean and Pacific
O’Dea 2003
Friday, 7 October 2011 bryozoan estimate
Contrasting seasonality between bryozoan estimate Caribbean and Pacific
O’Dea 2003
Friday, 7 October 2011 Early-Mid Pliocene North Atlantic
Knowles et al. 2009
Friday, 7 October 2011 Early-Mid Pliocene North Atlantic
Knowles et al. 2009
Friday, 7 October 2011 5. palaeolatitudinal distribution of bryozoan carbonates through time
Friday, 7 October 2011 Uniformitarianism
‘Present is the Key to the Past'
Charles Lyell (1797-1875)
Friday, 7 October 2011 Global distribution of carbonate deposition at the present-day
Friday, 7 October 2011 Global distribution of carbonate deposition at the present-day
Friday, 7 October 2011 PalaeolatitudinalLatitudinal distribution ofdistribution bryozoan-rich ofcarbonate bryozoan-rich sediments through sediments time
Taylor & Allison 1998. Geology 26: 459-462
Friday, 7 October 2011 PalaeolatitudinalLatitudinal distribution ofdistribution bryozoan-rich ofcarbonate bryozoan-rich sediments through sediments time
Tropics
Taylor & Allison 1998. Geology 26: 459-462
Friday, 7 October 2011 PalaeolatitudinalLatitudinal distribution ofdistribution bryozoan-rich ofcarbonate bryozoan-rich sediments through sediments time
Tropics
Taylor & Allison 1998. Geology 26: 459-462
• post-Palaeozoic are nearly all non-tropical
Friday, 7 October 2011 PalaeolatitudinalLatitudinal distribution ofdistribution bryozoan-rich ofcarbonate bryozoan-rich sediments through sediments time
Tropics
Taylor & Allison 1998. Geology 26: 459-462
• post-Palaeozoic are nearly all non-tropical • but Palaeozoic are pan-global
Friday, 7 October 2011 Palaeolatitudinal distribution of bryozoan-rich sediments 60
post-Palaeozoic 45 Palaeozoic
30
frequency 15
0 0-15 15-30 30-45 45-60 60-75 75-90 palaeolatitude (degrees) Friday, 7 October 2011 Palaeozoic post-Palaeozoic
Cincinnatian Series - Coralline Crag - Upper Ordovician, USA Pliocene, England Tropical carbonate Temperate carbonate
Friday, 7 October 2011 Bryozoan assemblage species richness vs latitude in the eastern (black dots) and western (white dots) North Atlantic
• no gradient of increasing species diversity into tropics (cf. many other phyla)
• bryozoans can be diverse in the tropics but have a relatively low biomass (as in Indonesian Cenozoic)
Clarke & Lidgard 2000. Journal of Animal Ecology 69: 799-814 Friday, 7 October 2011 Postscript: analysis of annual growth bands as proxy for phytoplankton productivity in the Antarctic
Cellarinella Recent Antarctica cf. tree rings Friday, 7 October 2011 Summary and conclusions
Akkeshi Bay
Friday, 7 October 2011 Summary and conclusions
• bryozoans at the present day inhabit many aquatic environments but are most diverse on continental shelves
Akkeshi Bay
Friday, 7 October 2011 Summary and conclusions
• bryozoans at the present day inhabit many aquatic environments but are most diverse on continental shelves
• colony-form analysis must be treated cautiously
Akkeshi Bay
Friday, 7 October 2011 Summary and conclusions
• bryozoans at the present day inhabit many aquatic environments but are most diverse on continental shelves
• colony-form analysis must be treated cautiously
• in some species relative branch diameter can be used as a palaeobathymetric indicator
Akkeshi Bay
Friday, 7 October 2011 Summary and conclusions
• bryozoans at the present day inhabit many aquatic environments but are most diverse on continental shelves
• colony-form analysis must be treated cautiously
• in some species relative branch diameter can be used as a palaeobathymetric indicator
• zooid size correlates with temperature at time of budding and can be used to indicate relative palaeotemperature and also MART
Akkeshi Bay
Friday, 7 October 2011 Summary and conclusions
• bryozoans at the present day inhabit many aquatic environments but are most diverse on continental shelves
• colony-form analysis must be treated cautiously
• in some species relative branch diameter can be used as a palaeobathymetric indicator
• zooid size correlates with temperature at time of budding and can be used to indicate relative palaeotemperature and also MART
• the latitudinal distribution of carbonate-producing bryozoans has changed through time Akkeshi Bay
Friday, 7 October 2011