Middle to Late Ordovician rocky bottoms and rocky shores from the Manitoulin Island area, Ontario: Reply

1990 ◽  
Vol 27 (1) ◽  
pp. 159-159
Author(s):  
Markes E. Johnson ◽  
Rong Jia-Yu
Keyword(s):  
Late Ordovician ◽  
Rocky Shores ◽  
Island Area ◽  
Rocky Bottoms

Middle to Late Ordovician rocky bottoms and rocky shores from the Manitoulin Island area, Ontario: Discussion

1990 ◽  
Vol 27 (1) ◽  
pp. 158-158
Author(s):  
James A. Robertson
Keyword(s):  
Late Ordovician ◽  
Rocky Shores ◽  
Island Area ◽  
Rocky Bottoms

Middle to Late Ordovician rocky bottoms and rocky shores from the Manitoulin Island area, Ontario

1989 ◽  
Vol 26 (4) ◽  
pp. 642-653 ◽  
Author(s):  
Markes E. Johnson ◽  
Rong Jia-yu
Keyword(s):  
North America ◽  
Rocky Shore ◽  
Late Ordovician ◽  
Depositional Environments ◽  
Lake Huron ◽  
Rocky Shores ◽  
Rare Association ◽  
Brachiopod Fauna ◽  
Rocky Bottoms ◽  
Topographic Relief

The Precambrian Lorrain Quartzite is exposed on Manitoulin, Great Cloche, and Birch islands in Lake Huron off the mainland of Ontario. Metamorphism created a massive unit, which later formed a resistant angular unconformity overlain by a succession of strata deposited from Middle to Late Ordovician times. At the start of Ordovician sedimentation, topographic relief was at least 125 m when the quartzite hills formed an archipelago of small, rocky islands. The Ordovician–Precambrian unconformity provides insight on a changing series of depositional environments over rocky bottoms and rocky shores. Four Ordovician units are well represented. The Swift Current Formation includes some red beds, while the younger Cloche Island and Cobourg formations are carbonates. The Collingwood Formation is a black shale. The first three include eroded quartzite clasts typical of a rocky-shore setting. The unconformity marked by the Collingwood Formation indicates a rapid transgression with little time for the accumulation of eroded quartzite clasts. A rich trilobite and orthid brachiopod fauna was recovered from the Collingwood Formation immediately above the Lorrain Quartzite and it represents a rare association that lived in a rocky-bottom setting. This fauna includes the first-reported occurrence of the genus Triarthrus from Manitoulin Island. The Collingwood transgression is equated with a major rise in sea level widely recognized elsewhere in North America and Scandinavia.

scholarly journals Drastic effects of Climate Change on Mediterranean marine forests

2018 ◽  
Author(s):  
Jana Verdura ◽  
Alba Vergés ◽  
Jorge Santamaría ◽  
Sònia de Caralt ◽  
Enric Ballesteros ◽  
...  
Keyword(s):  
Climate Change ◽  
Natural Populations ◽  
Biodiversity Loss ◽  
Habitat Destruction ◽  
Rocky Shores ◽  
Fellowship Program ◽  
Summer Period ◽  
Marine Habitat ◽  
Radiation Conditions ◽  
Rocky Bottoms

Macroalgal forests have gone missing from most temperate rocky shores during the last decades, triggering an important biodiversity loss. Cystoseira species are some of the main marine habitat-forming species on shallow water Mediterranean rocky bottoms and follow the same tendency, mainly related to habitat destruction and pollution. However, here we suggest that anormal positive thermal events may contribute to this widespread Cystoseira decline. Monitoring thorough natural populations showed a drastic decline on a natural and relict C. crinita population in terms of density and structure coinciding with anormal high temperatures experienced during a summer period. Additionally, we experimentally test in the laboratory the cause-effect of those temperatures and UV radiation conditions experienced in the field on C. crinita populations. Although, C. crinita is able to resist high temperature picks, usually reached in Mediterranean summers, exceptional and maintained periods as those experienced during extreme events (28ºC) lead to the death of all individuals, compromising the viability and conservation of these forest-forming populations. We show how climate change may seriously compromise algal populations and synergically act with historical drivers of macroalgal decline (pollution, habitat destruction and herbivorism). Financial support from EU2020 (R+I) under grant agreement No 689518 (MERCES), MINECO (CGL2016-76341-R) and from University of Girona under congress assistance fellowship program for PhD and master students.

scholarly journals Drastic effects of climate change on Mediterranean marine forests

2018 ◽  
Author(s):  
Jana Verdura ◽  
Alba Vergés ◽  
Jorge Santamaría ◽  
Sònia de Caralt ◽  
Enric Ballesteros ◽  
...  
Keyword(s):  
Climate Change ◽  
High Temperature ◽  
Shallow Water ◽  
High Temperatures ◽  
Size Structure ◽  
Habitat Destruction ◽  
Rocky Shores ◽  
Relict Population ◽  
Summer Temperatures ◽  
Rocky Bottoms

Macroalgal forests have gone missing in several temperate rocky shores during the last decades, triggering important changes in the seascape. Cystoseira species are some of the main habitat-forming species on shallow water Mediterranean rocky bottoms and follow the same tendency, which has been mainly related to habitat destruction and pollution. Here we suggest that abnormal positive thermal events may have contributed to this widespread Cystoseira decline. Densities and size structure distribution of C. crinita showed a drastic decline on a relict population coinciding with abnormal high summer temperatures. Additionally, we experimentally tested in the laboratory the cause-effect of high temperatures and UV radiation on C. crinita populations. Although, C. crinita was able to resist punctual high temperature peaks, exceptional and maintained periods of high temperatures (28ºC) lead to the death of all individuals, compromising the viability of these populations. Thus, climate change may seriously compromise C. crinita stands and act synergically with historical drivers of macroalgal decline such as pollution, habitat destruction and increased herbivorism.

scholarly journals Drastic effects of climate change on Mediterranean marine forests

2018 ◽  
Author(s):  
Jana Verdura ◽  
Alba Vergés ◽  
Jorge Santamaría ◽  
Sònia de Caralt ◽  
Enric Ballesteros ◽  
...  
Keyword(s):  
Climate Change ◽  
High Temperature ◽  
Shallow Water ◽  
High Temperatures ◽  
Size Structure ◽  
Habitat Destruction ◽  
Rocky Shores ◽  
Relict Population ◽  
Summer Temperatures ◽  
Rocky Bottoms

Macroalgal forests have gone missing in several temperate rocky shores during the last decades, triggering important changes in the seascape. Cystoseira species are some of the main habitat-forming species on shallow water Mediterranean rocky bottoms and follow the same tendency, which has been mainly related to habitat destruction and pollution. Here we suggest that abnormal positive thermal events may have contributed to this widespread Cystoseira decline. Densities and size structure distribution of C. crinita showed a drastic decline on a relict population coinciding with abnormal high summer temperatures. Additionally, we experimentally tested in the laboratory the cause-effect of high temperatures and UV radiation on C. crinita populations. Although, C. crinita was able to resist punctual high temperature peaks, exceptional and maintained periods of high temperatures (28ºC) lead to the death of all individuals, compromising the viability of these populations. Thus, climate change may seriously compromise C. crinita stands and act synergically with historical drivers of macroalgal decline such as pollution, habitat destruction and increased herbivorism.

Author response for "Middle to Late Ordovician carbon isotope chemostratigraphy of the Lower Yangtze Platform: Implications for global correlation"

2020 ◽  
Author(s):  
Fangyi Gong ◽  
Michael M. Joachimski ◽  
Guanzhou Yan ◽  
Lixia Li ◽  
Xin Wei ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Late Ordovician ◽  
Author Response ◽  
Yangtze Platform ◽  
Global Correlation ◽  
Lower Yangtze
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