ABS'IRAcr Submarine canyons in the Mediterranean and Black Seas stand out as globally differe... more ABS'IRAcr Submarine canyons in the Mediterranean and Black Seas stand out as globally different based on studies of global canyon geomorphology; they are more closely spaced, more dendritic (more limbs per unit area), shorter, have the smallest mean area, are among the most steep and have a smaller depth range than canyons that occur in other regions of the world. Here we present the results of a multivariate analysis of submarine canyon geomorphology to explore in more detail the apparently unique attributes of Mediterranean canyons. We fmd that Mediterranean canyons can be divided into six Classes, dominated by "Class 4" that is characterized by small area, close canyon spacing and a relatively high percentage of shelf incising canyons. On a global basis, Class 4 canyons are found to occur mainly (68%) on active continental margins. Examples of other regions in the world containing large numbers of Class 4 canyons are described.
To protect the diversity of marine life in Australia’s Exclusive Economic Zone (EEZ), the federal... more To protect the diversity of marine life in Australia’s Exclusive Economic Zone (EEZ), the federal parliament has passed the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. The Act is being implemented through the design of a national representative system of marine protected areas (MPAs) that will place under protection a representative portion of Australia’s EEZ by 2012. There have already been 13 MPAs nominated for the southeast region in 2006.Limited biological data in Australia’s EEZ has resulted in biophysical information compiled by Geoscience Australia being used as a proxy for seabed biodiversity in support of marine conservation planning. Information we use to characterise the seabed includes bathymetry, geomorphology, acoustic properties, sediment properties, and slope and sediment mobilisation due to waves and tides. To better characterise habitats on the Australian continental shelf, Geoscience Australia is creating seascape maps (similar to geolo...
The aim of this study is to assess the global occurrence of large submarine canyons to provide co... more The aim of this study is to assess the global occurrence of large submarine canyons to provide context and
guidance for discussions regarding canyon occurrence, distribution, geological and oceanographic significance
and conservation. Based on an analysis of the ETOPO1 data set, this study has compiled the first inventory of
5849 separate large submarine canyons in the world ocean. Active continental margins contain 15% more
canyons (2586, equal to 44.2% of all canyons) than passive margins (2244, equal to 38.4%) and the canyons are
steeper, shorter, more dendritic and more closely spaced on active than on passive continental margins. This
study confirms observations of earlier workers that a relationship exists between canyon slope and canyon
spacing (increased canyon slope correlates with closer canyon spacing). The greatest canyon spacing occurs in
the Arctic and the Antarctic whereas canyons are more closely spaced in the Mediterranean than in other
areas.
River-associated, shelf-incising canyons are more numerous on active continental margins (n=119) than on
passive margins (n=34). They are most common on the western margins of South and North America where
they comprise 11.7% and 8.6% of canyons respectively, but are absent from the margins of Australia and
Antarctica. Geographic areas having relatively high rates of sediment export to continental margins, from
either glacial or fluvial sources operating over geologic timescales, have greater numbers of shelf-incising
canyons than geographic areas having relatively low rates of sediment export to continental margins. This
observation is consistent with the origins of some canyons being related to erosive turbidity flows derived
from fluvial and shelf sediment sources.
Other workers have shown that benthic ecosystems in shelf-incising canyons contain greater diversity and
biomass than non-incising canyons, and that ecosystems located above 1500 m water depth are more
vulnerable to destructive fishing practices (bottom trawling) and ocean acidification caused by anthropogenic
climate change. The present study provides the means to assess the relative significance of canyons located in
different geographic regions. On this basis, the importance of conservation for submarine canyon ecosystems
is greater for Australia, islands and northeast Asia than for other regions.
A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels fo... more A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels for global coastal segments at 1 km or shorter resolution. These characteristics are summarized for six US Marine Biodiversity Observation Network (MBON) sites and one MBON Pole to Pole of the Americas site in Argentina. The global coastlines CMECS classifications were produced from a partitioning of a 30 m Landsat-derived shoreline vector that was segmented into 4 million 1 km or shorter segments. Each segment was attributed with values from 10 variables that represent the ecological settings in which the coastline occurs, including properties of the adjacent water, adjacent land, and coastline itself. The 4 million segments were classified into 81,000 coastal segment units (CSUs) as unique combinations of variable classes. We summarize the process to develop the CSUs and derive summary descriptions for the seven MBON case study sites. We discuss the intended application of the new CSU da...
90 km across the continental shelf. This is the deepest shelf valley yet found in the Great Barri... more 90 km across the continental shelf. This is the deepest shelf valley yet found in the Great Barrier Reef and is well below the maximum depth of fluvial incision that could have occurred under a 120 m, eustatic sea level low-stand, as what occurred on incision model may explain the observation of other workers, that sediment is exported from the Great Barrier Reef shelf to the Marine Geology 220 (2005) 181–204 www.elsevier.com/locate/margeothis margin during the last ice age. These valleys appear to have formed by a combination of reef growth and tidal current scour, probably in relation to a sea level at around 30–50 m below its present position. Tidally incised depressions in the valley floor exhibit closed bathymetric contours at both ends. Valley floor sediments are mainly calcareous muddy, gravelly sand on the middle shelf, giving way to well-sorted, gravely sand containing a large relict fraction on the outer shelf. The valley extends between broad platform reefs and framework ...
Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic conti... more Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic continental shelves. The Mac.Robertson shelf is relatively narrow with rugged, inner-shelf topography and shallow outer-shelf banks swept by the west-flowing Antarctic Coastal Current. U-shaped valleys cut across the shelf. It has thin sedimentary cover, deposited and eroded by cycles of glacial advance and retreat through the Neogene and Quaternary. Modern sedimentation is diatom-rich siliceous, muddy ooze in shelf deeps, while, on the banks, phytodetritus, calcareous bioclasts and terrigenous material are mixed by iceberg ploughing. Prydz Bay is a large embayment fed by the Amery Ice Shelf. It has a broad inner-shelf deep area and outer bank, with depths ranging from 2400 m beneath the ice shelf to 100 m on the outer banks. A clockwise gyre flows through the bay. Fine mud and siliceous ooze drape the seafloor; however, banks are scoured by icebergs to depths as great as 500 m. The Mac.Rober...
Measurements of water turbidity, currents, seafloor sediment samples and geophysical data documen... more Measurements of water turbidity, currents, seafloor sediment samples and geophysical data document the sedimentary processes and the Late Quaternary sedimentary history of a continental shelf valley system on the East Antarctic continental margin. The valley is up to 1200 m in depth and strikes across the shelf; it is interpreted as having formed by glacial erosion processes. On the outer-shelf
Megaripple, sandwave and sand ribbon distributions are mapped from 3088 km of detailed side-scan ... more Megaripple, sandwave and sand ribbon distributions are mapped from 3088 km of detailed side-scan sonar data, collected in a macrotidal estuary. Sandwave orientations indicate localised bedload divergences which form part of a larger transport system. The previously ...
ABS'IRAcr Submarine canyons in the Mediterranean and Black Seas stand out as globally differe... more ABS'IRAcr Submarine canyons in the Mediterranean and Black Seas stand out as globally different based on studies of global canyon geomorphology; they are more closely spaced, more dendritic (more limbs per unit area), shorter, have the smallest mean area, are among the most steep and have a smaller depth range than canyons that occur in other regions of the world. Here we present the results of a multivariate analysis of submarine canyon geomorphology to explore in more detail the apparently unique attributes of Mediterranean canyons. We fmd that Mediterranean canyons can be divided into six Classes, dominated by "Class 4" that is characterized by small area, close canyon spacing and a relatively high percentage of shelf incising canyons. On a global basis, Class 4 canyons are found to occur mainly (68%) on active continental margins. Examples of other regions in the world containing large numbers of Class 4 canyons are described.
To protect the diversity of marine life in Australia’s Exclusive Economic Zone (EEZ), the federal... more To protect the diversity of marine life in Australia’s Exclusive Economic Zone (EEZ), the federal parliament has passed the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. The Act is being implemented through the design of a national representative system of marine protected areas (MPAs) that will place under protection a representative portion of Australia’s EEZ by 2012. There have already been 13 MPAs nominated for the southeast region in 2006.Limited biological data in Australia’s EEZ has resulted in biophysical information compiled by Geoscience Australia being used as a proxy for seabed biodiversity in support of marine conservation planning. Information we use to characterise the seabed includes bathymetry, geomorphology, acoustic properties, sediment properties, and slope and sediment mobilisation due to waves and tides. To better characterise habitats on the Australian continental shelf, Geoscience Australia is creating seascape maps (similar to geolo...
The aim of this study is to assess the global occurrence of large submarine canyons to provide co... more The aim of this study is to assess the global occurrence of large submarine canyons to provide context and
guidance for discussions regarding canyon occurrence, distribution, geological and oceanographic significance
and conservation. Based on an analysis of the ETOPO1 data set, this study has compiled the first inventory of
5849 separate large submarine canyons in the world ocean. Active continental margins contain 15% more
canyons (2586, equal to 44.2% of all canyons) than passive margins (2244, equal to 38.4%) and the canyons are
steeper, shorter, more dendritic and more closely spaced on active than on passive continental margins. This
study confirms observations of earlier workers that a relationship exists between canyon slope and canyon
spacing (increased canyon slope correlates with closer canyon spacing). The greatest canyon spacing occurs in
the Arctic and the Antarctic whereas canyons are more closely spaced in the Mediterranean than in other
areas.
River-associated, shelf-incising canyons are more numerous on active continental margins (n=119) than on
passive margins (n=34). They are most common on the western margins of South and North America where
they comprise 11.7% and 8.6% of canyons respectively, but are absent from the margins of Australia and
Antarctica. Geographic areas having relatively high rates of sediment export to continental margins, from
either glacial or fluvial sources operating over geologic timescales, have greater numbers of shelf-incising
canyons than geographic areas having relatively low rates of sediment export to continental margins. This
observation is consistent with the origins of some canyons being related to erosive turbidity flows derived
from fluvial and shelf sediment sources.
Other workers have shown that benthic ecosystems in shelf-incising canyons contain greater diversity and
biomass than non-incising canyons, and that ecosystems located above 1500 m water depth are more
vulnerable to destructive fishing practices (bottom trawling) and ocean acidification caused by anthropogenic
climate change. The present study provides the means to assess the relative significance of canyons located in
different geographic regions. On this basis, the importance of conservation for submarine canyon ecosystems
is greater for Australia, islands and northeast Asia than for other regions.
A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels fo... more A new data layer provides Coastal and Marine Ecological Classification Standard (CMECS) labels for global coastal segments at 1 km or shorter resolution. These characteristics are summarized for six US Marine Biodiversity Observation Network (MBON) sites and one MBON Pole to Pole of the Americas site in Argentina. The global coastlines CMECS classifications were produced from a partitioning of a 30 m Landsat-derived shoreline vector that was segmented into 4 million 1 km or shorter segments. Each segment was attributed with values from 10 variables that represent the ecological settings in which the coastline occurs, including properties of the adjacent water, adjacent land, and coastline itself. The 4 million segments were classified into 81,000 coastal segment units (CSUs) as unique combinations of variable classes. We summarize the process to develop the CSUs and derive summary descriptions for the seven MBON case study sites. We discuss the intended application of the new CSU da...
90 km across the continental shelf. This is the deepest shelf valley yet found in the Great Barri... more 90 km across the continental shelf. This is the deepest shelf valley yet found in the Great Barrier Reef and is well below the maximum depth of fluvial incision that could have occurred under a 120 m, eustatic sea level low-stand, as what occurred on incision model may explain the observation of other workers, that sediment is exported from the Great Barrier Reef shelf to the Marine Geology 220 (2005) 181–204 www.elsevier.com/locate/margeothis margin during the last ice age. These valleys appear to have formed by a combination of reef growth and tidal current scour, probably in relation to a sea level at around 30–50 m below its present position. Tidally incised depressions in the valley floor exhibit closed bathymetric contours at both ends. Valley floor sediments are mainly calcareous muddy, gravelly sand on the middle shelf, giving way to well-sorted, gravely sand containing a large relict fraction on the outer shelf. The valley extends between broad platform reefs and framework ...
Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic conti... more Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic continental shelves. The Mac.Robertson shelf is relatively narrow with rugged, inner-shelf topography and shallow outer-shelf banks swept by the west-flowing Antarctic Coastal Current. U-shaped valleys cut across the shelf. It has thin sedimentary cover, deposited and eroded by cycles of glacial advance and retreat through the Neogene and Quaternary. Modern sedimentation is diatom-rich siliceous, muddy ooze in shelf deeps, while, on the banks, phytodetritus, calcareous bioclasts and terrigenous material are mixed by iceberg ploughing. Prydz Bay is a large embayment fed by the Amery Ice Shelf. It has a broad inner-shelf deep area and outer bank, with depths ranging from 2400 m beneath the ice shelf to 100 m on the outer banks. A clockwise gyre flows through the bay. Fine mud and siliceous ooze drape the seafloor; however, banks are scoured by icebergs to depths as great as 500 m. The Mac.Rober...
Measurements of water turbidity, currents, seafloor sediment samples and geophysical data documen... more Measurements of water turbidity, currents, seafloor sediment samples and geophysical data document the sedimentary processes and the Late Quaternary sedimentary history of a continental shelf valley system on the East Antarctic continental margin. The valley is up to 1200 m in depth and strikes across the shelf; it is interpreted as having formed by glacial erosion processes. On the outer-shelf
Megaripple, sandwave and sand ribbon distributions are mapped from 3088 km of detailed side-scan ... more Megaripple, sandwave and sand ribbon distributions are mapped from 3088 km of detailed side-scan sonar data, collected in a macrotidal estuary. Sandwave orientations indicate localised bedload divergences which form part of a larger transport system. The previously ...
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Papers by Peter Harris
guidance for discussions regarding canyon occurrence, distribution, geological and oceanographic significance
and conservation. Based on an analysis of the ETOPO1 data set, this study has compiled the first inventory of
5849 separate large submarine canyons in the world ocean. Active continental margins contain 15% more
canyons (2586, equal to 44.2% of all canyons) than passive margins (2244, equal to 38.4%) and the canyons are
steeper, shorter, more dendritic and more closely spaced on active than on passive continental margins. This
study confirms observations of earlier workers that a relationship exists between canyon slope and canyon
spacing (increased canyon slope correlates with closer canyon spacing). The greatest canyon spacing occurs in
the Arctic and the Antarctic whereas canyons are more closely spaced in the Mediterranean than in other
areas.
River-associated, shelf-incising canyons are more numerous on active continental margins (n=119) than on
passive margins (n=34). They are most common on the western margins of South and North America where
they comprise 11.7% and 8.6% of canyons respectively, but are absent from the margins of Australia and
Antarctica. Geographic areas having relatively high rates of sediment export to continental margins, from
either glacial or fluvial sources operating over geologic timescales, have greater numbers of shelf-incising
canyons than geographic areas having relatively low rates of sediment export to continental margins. This
observation is consistent with the origins of some canyons being related to erosive turbidity flows derived
from fluvial and shelf sediment sources.
Other workers have shown that benthic ecosystems in shelf-incising canyons contain greater diversity and
biomass than non-incising canyons, and that ecosystems located above 1500 m water depth are more
vulnerable to destructive fishing practices (bottom trawling) and ocean acidification caused by anthropogenic
climate change. The present study provides the means to assess the relative significance of canyons located in
different geographic regions. On this basis, the importance of conservation for submarine canyon ecosystems
is greater for Australia, islands and northeast Asia than for other regions.
guidance for discussions regarding canyon occurrence, distribution, geological and oceanographic significance
and conservation. Based on an analysis of the ETOPO1 data set, this study has compiled the first inventory of
5849 separate large submarine canyons in the world ocean. Active continental margins contain 15% more
canyons (2586, equal to 44.2% of all canyons) than passive margins (2244, equal to 38.4%) and the canyons are
steeper, shorter, more dendritic and more closely spaced on active than on passive continental margins. This
study confirms observations of earlier workers that a relationship exists between canyon slope and canyon
spacing (increased canyon slope correlates with closer canyon spacing). The greatest canyon spacing occurs in
the Arctic and the Antarctic whereas canyons are more closely spaced in the Mediterranean than in other
areas.
River-associated, shelf-incising canyons are more numerous on active continental margins (n=119) than on
passive margins (n=34). They are most common on the western margins of South and North America where
they comprise 11.7% and 8.6% of canyons respectively, but are absent from the margins of Australia and
Antarctica. Geographic areas having relatively high rates of sediment export to continental margins, from
either glacial or fluvial sources operating over geologic timescales, have greater numbers of shelf-incising
canyons than geographic areas having relatively low rates of sediment export to continental margins. This
observation is consistent with the origins of some canyons being related to erosive turbidity flows derived
from fluvial and shelf sediment sources.
Other workers have shown that benthic ecosystems in shelf-incising canyons contain greater diversity and
biomass than non-incising canyons, and that ecosystems located above 1500 m water depth are more
vulnerable to destructive fishing practices (bottom trawling) and ocean acidification caused by anthropogenic
climate change. The present study provides the means to assess the relative significance of canyons located in
different geographic regions. On this basis, the importance of conservation for submarine canyon ecosystems
is greater for Australia, islands and northeast Asia than for other regions.