- Email: [email protected]
The geomorphology of Canada: An introduction
2664
Book Reviews
tetrapods (E. H. Colbert); all provide good summaries of the paleontological record. Cooper and Shergold note the biogeographic affinities of the Cambrian faunas with Australia, and more particularly with China and Siberia, and also the links to North America. Thompson notes the ci~um-~ndwana distribution of Lower Jurassic ammonites and the progressively more restricted distribution of Late Mesozoic faunas, leading to the distinct endemism of the Weddellian Province in Early Tertiary time. He also touches on the apparent role of the South Polar regions as an evolutionary center during the Late Mesozoic and Early Tertiary and the radiation of various groups to form modern low-latitude faunas. Truswell provides an excellent discussion of the role early fossil plant discoveries had in the development of thinking about former climates and the recognition that modern climates must be atypical of earth history. This is followed by a review of the paleobotany, with particular emphasis on the Gondwana sequence and the Late Me~zoic-Cenozoic. The discussion ofplant growth at high latitudes is most appropriate, considering that some Permian plants almost certainly grew at latitudes more poleward than anything known today. The two chapters on vertebrate paleontology show how recently. Most of these discoveries have been made, and, as Colbert notes. new discoveries can be expected which will contribute to both biogeographic patterns and paleoenvironmental interpretations. The chapters Py J. C. Behrendt on hydrocarbons and by P. D. Rowley, P. R. Wilhams, and D. E. Pride on metallic and nonmetallic resources provide overviews pointing out both the sparsity of dataconsider the spacing of seismic tracks and the dimensions (56 X 5 km) of the Prudhoe Bay field in Alaska-and the lack of any known economic resource. As others have said, it would take a huge increase in the price of oil and the discovery of a giant or, more likely, a supergiant field for hydrocarbon exploitation to approach economic viability. Likewise, only high-value-low-volume metallic resources would appear to be exploitable. The Dufek Gabbro is perhaps the one known “target” in the eyes of the economic geologist. However. the Madrid Protocols, adopted by the Parties (nations) to the Antarctic Treaty in I99 1, have placed a minimum fifty-year ban on nonliving resource exploration and development. The final chapter by W. A. Cassidy on meteorites highlights one of the unique aspects of Antarctica to earth sciences. The relatively recent ( 1969) discovery of the meteorite “stranding” surfaces has provided the meteoriticists with an unusual opportunity to investigate falls that must, in some cases, be in as near a pristine a state as is achievable outside actually catching one in a sterilized container. New varieties of common meteorites have been found, and both lunar and Mars samples recovered. The collections also offer a way to assess past rates of falls and to investigate ~aciolo~~ phenomena. The book is well produced, halftones are excellent, and there is only a scattering of typographic errors. A geologic map ofthe continent as a whole would have been most useful. As the editor admits, some topics are missing; discussion of the McMurdo Volcanic Province, which includes Mount Erebus with its active phonolite lava lake, and
the tectonic evolution of Antarctica from breakup to the Present would have been most valuable. These aspects do not seriously diminish the quality and usefulness of the book. With multiauthored books, time delays are common, and, unfo~unately, not all authors used the opportunity given them to update their chapters. For most earth scientists, the price of the book is beyond reach; nevertheless, it ought to be in every library. In summary, I offer some observations. Antarctica holds information critical to understanding the course of the earth’s climate, leading up to the present interglacial. Glacially related deposits of the “Sirius” Group continue to fuel the fire of controversy with the collection in 1990-91 of large leaves of Nocho/&us from the Dominion Range, 300 miles from the South Pole. The implications of the Sirius Group, if dated correctly by P. N. Webb and D. H. Harwood as an Upper Pliocene deposit, to the history of climate change are profound. They suggest that Antarctica was never as cold before that time as it has been ever since: and, if that is correct, then there is the problem of why the inferred major deglaciation is not seen in the deep-sea oxygen-isotope records. On the subject of plants, the Permian vegetation at high latitudes, assuming the paleomagnetic record is well enough constrained, provides very powerful “ground truth” for climate model studies that seek to reproduce conditions with very different continental and oceanic distributions. The Transantarctic Mountains mark the edge of one ofthe world’s greatest intracontinental structural discontinuities. between the 40 km crust of East Antarctica and the 20 km thick crust of much of West Antarctica. The tectonic development of this discontinuity reflects rifting, canning with breakup of Gondwana and continuing intermittently until today, as indicated by the Victoria Land Basin and the McMurdo Volcanic Province. The tectonic evolution of the region has had a profound impact on developing oceans, ocean circulation patterns, and biogeographic patterns, in the latter case, epitomized by the fossil marsupial from Seymour Island. The recently proposed late Precamb~an reconstructions of the continents, developed independently by I. W. D. Dalziel, P. F. Hoffman, and E. M. Moores, provide a new way of looking at the tectonic evolution of Antarctica and some fauna1 relationships (the Cambrian trilobite links with North America), structural trends and age provinces (the Shackleton Range), and perhaps also the enigmatic Urtjell Group in western Queen Maud Land. In numerous ways, Antarctic earth science is coming into the mainstream. This volume provides an excellent summary of many aspects of Antarctic earth science. If the editor is proud of this book, he is justifiably so.
The Geomorphology of Canada: An Introduction by A. S. Trenhaile. Oxford University Press, 1990, viii + 240p.. US $35 (cloth: ISBN O19-540791-I).
who are interested in increasing the Canadian content in their lectures (good examples of spits, earthflows, stream capture, and the largest giacial horn in Canada). Although the sources of many of the examples are from international as well as Canadian journals, this text makes it much easier to use some of the superior examples of phenomena found in Canada. Additional strengths of the book include a lengthy reference list, glossary, useful index, and review of the SI system of measurement. Although there are more than 270 references in the eleven-page list. the author acknowledges that not all relevant papers are cited (e.g., neither G. Young’s work on the Huronian nor papers by A. Dreimanis on Port Talbot are referenced). Whether or not the student will find these omissions disconcerting is questionable; however, this is one area where the professor familiar with the current and classical literature can provide additional help for those students seeking it. Of the ten chapters, ranging in length from eleven to thirty pages, the longest is on glacial sediments and landforms (Chapter 6). This
THISISNOTA comprehensive book on the geomorphology of Canada, nor is it an introduction as the title page states. It is actually a geomorphology textbook for junior undergraduates. It has up-to-date, often succinct coverage of most topics found in g~mo~hology textbooks. Unde~tandably, with only 209 pages of chapter text, it does not present all topics in the depth that some students might seek. Still, this book meets one of its prime objectives, one that is especially relevant in Canada-it uses Canadian instead of USA or UK examples. Although most geomorphologists teaching in Canada are aware of Canadian examples and can incorporate them where appropriate, for students at this level it is very important to have a textbook that covers as many of such classroom examples as possible. The book will be useful to geomorphologists outside of Canada
Deportment of~eo~og~~~lSciences Byrd Polur Research Center Ohio State University 108 Scocc Hail 1090 Carmack Road Colcimbccs.OH 43210 USA
David H. Elliot
Book Reviews
2665
is entirely appropriate for a country that has been almost completely glaciated, has evidence for the first known ice age on Earth, has more fiords than any other country (apparently there are four times as many fiords in the Canadian Arctic as there are on the Pacific Coast of North America), was home to the largest ice sheet in the northern hemisphere, and is home to many glacial geologists and institutions studying Quatemary and glacial geology. When the length of chapters on glaciers and ice ages and the glaciation of Canada are added to Chapter 6, we find more than 30% of the text covers glaciation. Add the periglacial chapter (Chapter 7) and the coverage of glacial/periglacial topics is 41%. The other chapters, with percentage of space for each, include Physical Background ( II), Weathering (5), Mass Movement (9), Rivers ( I4), Coastal Processes and Landforms ( 13), and Karst (7). Physical Background is probably the least satisfactory of the chapters, providing a very sketchy review of physical geology that might be difficult for some students. Presumably, most will have had an introductory course in geology, for there are no diagrams and no glossary entries to help students with terms such as fore-arc basin
and structural components; some geographic features are mentioned in the text, but are not on any figures (Cobequid Mountains, Foxe Basin); the term Post-Precambrian is used where Phanerozoic would be preferred; and the Phanerozoic/Precambrian boundary is at 590 my whereas 570 my might be preferred in North America. But these are generally minor points in a very well-edited book. The diagrams are clear and useful, the print and layout make the book easy to read, and the wide outside margin on each page is useful for notes by students. I believe that students could benefit from additional information (e.g., differentiation of eskers and crevasse fillings, the Frank Slide, and what is meant by stream capacity) and more diagrams (e.g., more on patterned ground). Nevertheless, the book should find a niche in departments of geology, geography, and environmental science.
Oxygen Dynamics in the Chesapeake Bay: A Synthesis of Recent Research edited by D. E. Smith et al. Maryland Sea Grant, 1992, xvii + 234 p., US $24.95 (ISBN o-943676-50-9).
of the Bay. These results imply that nutrient loading must lx reduced to an unknown lower level before nutrient-limited conditions and improvements in water quality can occur. Robert Jonas examines the role of heterotrophic bacteria in water column oxygen dynamics. In Chapter 3 he notes that exceptionally high bacterial abundances are sustained throughout spring and summer in the Chesapeake, as compared with other estuaries. Observations of mid-water abundance maxima near the pycnocline indicate that bacteria may act as a significant barrier for downward diffusive reaeration of subpycnocline waters. Bacterial decomposition of particulate and dissolved organic matter appears to largely account for observed oxygen demand; however, sources of the labile organic matter remain poorly understood. Benthic-pelagic interactions are discussed by Michael Kemp and Walter R. Boynton in the final chapter. Both the coupling of sedimentary and water column processes over various time scales and the impacts of eutrophication and anoxia on benthic processes are considered. The authors conclude that planktonic respiration is more important than benthic processes during the spring period of decreasing bottom water oxygen; however, benthic respiration is more significant at the beginning and the end of anoxic periods. Slow benthic nutrient recycling appears to create a lag of months to several years between nutrient inputs and coupled water column productivity. Oxygen Dynamics in the Chesapeake Bay provides a comprehensive, well-integrated picture of what is known about the circulation and biogeochemical processes controlling O2 dynamics in that allimportant estuary. It has several features which should enhance its usefulness to the reader; among these is an overview summary which prefaces the four chapters with nineteen major scientific findings plus ten key implications of these findings for management decisions. Perhaps the most important feature is good connectivity between the chapters, which has resulted from substantial information sharing by ah five authors. The book should prove useful to researchers, teachers and managers interested in an integrated approach to understanding the variety of processes at work in estuarine environments.
THIS WELL-CONSTRUCTED volume examines
the processes controlling oxygen depletion in the Chesapeake Bay, the nation’s largest and most productive estuary. Also known as hypoxia, oxygen depletion is widely believed to be an important indicator of an estuary’s health. Recent changes in the extent and severity of hypoxia (as well as anoxia, complete dissolved oxygen removal) have spurred efforts to determine the relative contributions of natural processes and human activity to the system. Arranged in four chapters reflecting the recent works of researchers in four distinct areas, this book is in large part the result of a program of integrated research projects, funded since 1985 by the Maryland and Virginia Sea Grant programs in conjunction with the National Oceanic and Atmospheric Administration. Basically, the projects aim at detailing how water column processes and benthic-pelagic interactions regulate hypoxia, particularly in the mesohaline (5-20% salinity) region of the Bay. In the first chapter, William C. Boicourt reviews what is known about circulation processes in the Chesapeake Bay, summarizes hypoxia trends from 1950 to 1980, and discusses the relative importance of variations in freshwater input versus excess nutrient loading in controlling summertime hypoxia. He concludes that variations in the volume of spring river inflow to the bay control the buildup of a “buoyancy reservoir” which, in turn, controls the extent of water column stratification and thus, variations in oxygen supply to waters below the pycnocline. He further observes that the rate of vertical exchange controls the rate of reaeration of the bottom waters, but not oxygen depletion. In Chapter 2, Thomas C. Malone discusses the responses of phytoplankton and zooplankton communities to nutrient inputs, making a distinction between nutrient-limited and nutrient-saturated situations, the former resulting in higher productivity and the latter resulting in biomass-limited nutrient uptake. He concludes that the addition of new nutrient inputs to Chesapeake Bay has led to nutrient saturation resulting in the creation of greater phytoplankton biomass, rather than higher productivity. This biomass controls oxygen depletion rates which exceed the aerobic oxygen assimilation capacity
Early Organic Evolution: Implications for Mineral and Energy Resources edited by M. Schidlowski et al. Springer-Verlag, 1992, xvii + 556 p., US $298 (ISBN o-387-54460-7). Early Organic Evolution is the proceedings of the ninth Alfred Wegener Conference, the final meeting of IGCP Project 157 held in
Department of Geological Sciences The Ohio State University Columbus, OH 43210, USA
Marine Sciences Program University of North Carolina Chapel Hill, NC 27599
Carry D. McKenzie
Christopher S. Martens
Germany in 1988. Over the past 15 years, Project 157 has promoted the blending of organic geochemistry, economic geology, and evolutionary biology. This IGCP publication covers a diverse set of topics and truly reflects the interdisciplinary nature of the field of early organic evolution. Five sections divide the book into ( 1) Precambrian weathering and paleosols, (2) organic matter in Precambrian and
Book Reviews
tetrapods (E. H. Colbert); all provide good summaries of the paleontological record. Cooper and Shergold note the biogeographic affinities of the Cambrian faunas with Australia, and more particularly with China and Siberia, and also the links to North America. Thompson notes the ci~um-~ndwana distribution of Lower Jurassic ammonites and the progressively more restricted distribution of Late Mesozoic faunas, leading to the distinct endemism of the Weddellian Province in Early Tertiary time. He also touches on the apparent role of the South Polar regions as an evolutionary center during the Late Mesozoic and Early Tertiary and the radiation of various groups to form modern low-latitude faunas. Truswell provides an excellent discussion of the role early fossil plant discoveries had in the development of thinking about former climates and the recognition that modern climates must be atypical of earth history. This is followed by a review of the paleobotany, with particular emphasis on the Gondwana sequence and the Late Me~zoic-Cenozoic. The discussion ofplant growth at high latitudes is most appropriate, considering that some Permian plants almost certainly grew at latitudes more poleward than anything known today. The two chapters on vertebrate paleontology show how recently. Most of these discoveries have been made, and, as Colbert notes. new discoveries can be expected which will contribute to both biogeographic patterns and paleoenvironmental interpretations. The chapters Py J. C. Behrendt on hydrocarbons and by P. D. Rowley, P. R. Wilhams, and D. E. Pride on metallic and nonmetallic resources provide overviews pointing out both the sparsity of dataconsider the spacing of seismic tracks and the dimensions (56 X 5 km) of the Prudhoe Bay field in Alaska-and the lack of any known economic resource. As others have said, it would take a huge increase in the price of oil and the discovery of a giant or, more likely, a supergiant field for hydrocarbon exploitation to approach economic viability. Likewise, only high-value-low-volume metallic resources would appear to be exploitable. The Dufek Gabbro is perhaps the one known “target” in the eyes of the economic geologist. However. the Madrid Protocols, adopted by the Parties (nations) to the Antarctic Treaty in I99 1, have placed a minimum fifty-year ban on nonliving resource exploration and development. The final chapter by W. A. Cassidy on meteorites highlights one of the unique aspects of Antarctica to earth sciences. The relatively recent ( 1969) discovery of the meteorite “stranding” surfaces has provided the meteoriticists with an unusual opportunity to investigate falls that must, in some cases, be in as near a pristine a state as is achievable outside actually catching one in a sterilized container. New varieties of common meteorites have been found, and both lunar and Mars samples recovered. The collections also offer a way to assess past rates of falls and to investigate ~aciolo~~ phenomena. The book is well produced, halftones are excellent, and there is only a scattering of typographic errors. A geologic map ofthe continent as a whole would have been most useful. As the editor admits, some topics are missing; discussion of the McMurdo Volcanic Province, which includes Mount Erebus with its active phonolite lava lake, and
the tectonic evolution of Antarctica from breakup to the Present would have been most valuable. These aspects do not seriously diminish the quality and usefulness of the book. With multiauthored books, time delays are common, and, unfo~unately, not all authors used the opportunity given them to update their chapters. For most earth scientists, the price of the book is beyond reach; nevertheless, it ought to be in every library. In summary, I offer some observations. Antarctica holds information critical to understanding the course of the earth’s climate, leading up to the present interglacial. Glacially related deposits of the “Sirius” Group continue to fuel the fire of controversy with the collection in 1990-91 of large leaves of Nocho/&us from the Dominion Range, 300 miles from the South Pole. The implications of the Sirius Group, if dated correctly by P. N. Webb and D. H. Harwood as an Upper Pliocene deposit, to the history of climate change are profound. They suggest that Antarctica was never as cold before that time as it has been ever since: and, if that is correct, then there is the problem of why the inferred major deglaciation is not seen in the deep-sea oxygen-isotope records. On the subject of plants, the Permian vegetation at high latitudes, assuming the paleomagnetic record is well enough constrained, provides very powerful “ground truth” for climate model studies that seek to reproduce conditions with very different continental and oceanic distributions. The Transantarctic Mountains mark the edge of one ofthe world’s greatest intracontinental structural discontinuities. between the 40 km crust of East Antarctica and the 20 km thick crust of much of West Antarctica. The tectonic development of this discontinuity reflects rifting, canning with breakup of Gondwana and continuing intermittently until today, as indicated by the Victoria Land Basin and the McMurdo Volcanic Province. The tectonic evolution of the region has had a profound impact on developing oceans, ocean circulation patterns, and biogeographic patterns, in the latter case, epitomized by the fossil marsupial from Seymour Island. The recently proposed late Precamb~an reconstructions of the continents, developed independently by I. W. D. Dalziel, P. F. Hoffman, and E. M. Moores, provide a new way of looking at the tectonic evolution of Antarctica and some fauna1 relationships (the Cambrian trilobite links with North America), structural trends and age provinces (the Shackleton Range), and perhaps also the enigmatic Urtjell Group in western Queen Maud Land. In numerous ways, Antarctic earth science is coming into the mainstream. This volume provides an excellent summary of many aspects of Antarctic earth science. If the editor is proud of this book, he is justifiably so.
The Geomorphology of Canada: An Introduction by A. S. Trenhaile. Oxford University Press, 1990, viii + 240p.. US $35 (cloth: ISBN O19-540791-I).
who are interested in increasing the Canadian content in their lectures (good examples of spits, earthflows, stream capture, and the largest giacial horn in Canada). Although the sources of many of the examples are from international as well as Canadian journals, this text makes it much easier to use some of the superior examples of phenomena found in Canada. Additional strengths of the book include a lengthy reference list, glossary, useful index, and review of the SI system of measurement. Although there are more than 270 references in the eleven-page list. the author acknowledges that not all relevant papers are cited (e.g., neither G. Young’s work on the Huronian nor papers by A. Dreimanis on Port Talbot are referenced). Whether or not the student will find these omissions disconcerting is questionable; however, this is one area where the professor familiar with the current and classical literature can provide additional help for those students seeking it. Of the ten chapters, ranging in length from eleven to thirty pages, the longest is on glacial sediments and landforms (Chapter 6). This
THISISNOTA comprehensive book on the geomorphology of Canada, nor is it an introduction as the title page states. It is actually a geomorphology textbook for junior undergraduates. It has up-to-date, often succinct coverage of most topics found in g~mo~hology textbooks. Unde~tandably, with only 209 pages of chapter text, it does not present all topics in the depth that some students might seek. Still, this book meets one of its prime objectives, one that is especially relevant in Canada-it uses Canadian instead of USA or UK examples. Although most geomorphologists teaching in Canada are aware of Canadian examples and can incorporate them where appropriate, for students at this level it is very important to have a textbook that covers as many of such classroom examples as possible. The book will be useful to geomorphologists outside of Canada
Deportment of~eo~og~~~lSciences Byrd Polur Research Center Ohio State University 108 Scocc Hail 1090 Carmack Road Colcimbccs.OH 43210 USA
David H. Elliot
Book Reviews
2665
is entirely appropriate for a country that has been almost completely glaciated, has evidence for the first known ice age on Earth, has more fiords than any other country (apparently there are four times as many fiords in the Canadian Arctic as there are on the Pacific Coast of North America), was home to the largest ice sheet in the northern hemisphere, and is home to many glacial geologists and institutions studying Quatemary and glacial geology. When the length of chapters on glaciers and ice ages and the glaciation of Canada are added to Chapter 6, we find more than 30% of the text covers glaciation. Add the periglacial chapter (Chapter 7) and the coverage of glacial/periglacial topics is 41%. The other chapters, with percentage of space for each, include Physical Background ( II), Weathering (5), Mass Movement (9), Rivers ( I4), Coastal Processes and Landforms ( 13), and Karst (7). Physical Background is probably the least satisfactory of the chapters, providing a very sketchy review of physical geology that might be difficult for some students. Presumably, most will have had an introductory course in geology, for there are no diagrams and no glossary entries to help students with terms such as fore-arc basin
and structural components; some geographic features are mentioned in the text, but are not on any figures (Cobequid Mountains, Foxe Basin); the term Post-Precambrian is used where Phanerozoic would be preferred; and the Phanerozoic/Precambrian boundary is at 590 my whereas 570 my might be preferred in North America. But these are generally minor points in a very well-edited book. The diagrams are clear and useful, the print and layout make the book easy to read, and the wide outside margin on each page is useful for notes by students. I believe that students could benefit from additional information (e.g., differentiation of eskers and crevasse fillings, the Frank Slide, and what is meant by stream capacity) and more diagrams (e.g., more on patterned ground). Nevertheless, the book should find a niche in departments of geology, geography, and environmental science.
Oxygen Dynamics in the Chesapeake Bay: A Synthesis of Recent Research edited by D. E. Smith et al. Maryland Sea Grant, 1992, xvii + 234 p., US $24.95 (ISBN o-943676-50-9).
of the Bay. These results imply that nutrient loading must lx reduced to an unknown lower level before nutrient-limited conditions and improvements in water quality can occur. Robert Jonas examines the role of heterotrophic bacteria in water column oxygen dynamics. In Chapter 3 he notes that exceptionally high bacterial abundances are sustained throughout spring and summer in the Chesapeake, as compared with other estuaries. Observations of mid-water abundance maxima near the pycnocline indicate that bacteria may act as a significant barrier for downward diffusive reaeration of subpycnocline waters. Bacterial decomposition of particulate and dissolved organic matter appears to largely account for observed oxygen demand; however, sources of the labile organic matter remain poorly understood. Benthic-pelagic interactions are discussed by Michael Kemp and Walter R. Boynton in the final chapter. Both the coupling of sedimentary and water column processes over various time scales and the impacts of eutrophication and anoxia on benthic processes are considered. The authors conclude that planktonic respiration is more important than benthic processes during the spring period of decreasing bottom water oxygen; however, benthic respiration is more significant at the beginning and the end of anoxic periods. Slow benthic nutrient recycling appears to create a lag of months to several years between nutrient inputs and coupled water column productivity. Oxygen Dynamics in the Chesapeake Bay provides a comprehensive, well-integrated picture of what is known about the circulation and biogeochemical processes controlling O2 dynamics in that allimportant estuary. It has several features which should enhance its usefulness to the reader; among these is an overview summary which prefaces the four chapters with nineteen major scientific findings plus ten key implications of these findings for management decisions. Perhaps the most important feature is good connectivity between the chapters, which has resulted from substantial information sharing by ah five authors. The book should prove useful to researchers, teachers and managers interested in an integrated approach to understanding the variety of processes at work in estuarine environments.
THIS WELL-CONSTRUCTED volume examines
the processes controlling oxygen depletion in the Chesapeake Bay, the nation’s largest and most productive estuary. Also known as hypoxia, oxygen depletion is widely believed to be an important indicator of an estuary’s health. Recent changes in the extent and severity of hypoxia (as well as anoxia, complete dissolved oxygen removal) have spurred efforts to determine the relative contributions of natural processes and human activity to the system. Arranged in four chapters reflecting the recent works of researchers in four distinct areas, this book is in large part the result of a program of integrated research projects, funded since 1985 by the Maryland and Virginia Sea Grant programs in conjunction with the National Oceanic and Atmospheric Administration. Basically, the projects aim at detailing how water column processes and benthic-pelagic interactions regulate hypoxia, particularly in the mesohaline (5-20% salinity) region of the Bay. In the first chapter, William C. Boicourt reviews what is known about circulation processes in the Chesapeake Bay, summarizes hypoxia trends from 1950 to 1980, and discusses the relative importance of variations in freshwater input versus excess nutrient loading in controlling summertime hypoxia. He concludes that variations in the volume of spring river inflow to the bay control the buildup of a “buoyancy reservoir” which, in turn, controls the extent of water column stratification and thus, variations in oxygen supply to waters below the pycnocline. He further observes that the rate of vertical exchange controls the rate of reaeration of the bottom waters, but not oxygen depletion. In Chapter 2, Thomas C. Malone discusses the responses of phytoplankton and zooplankton communities to nutrient inputs, making a distinction between nutrient-limited and nutrient-saturated situations, the former resulting in higher productivity and the latter resulting in biomass-limited nutrient uptake. He concludes that the addition of new nutrient inputs to Chesapeake Bay has led to nutrient saturation resulting in the creation of greater phytoplankton biomass, rather than higher productivity. This biomass controls oxygen depletion rates which exceed the aerobic oxygen assimilation capacity
Early Organic Evolution: Implications for Mineral and Energy Resources edited by M. Schidlowski et al. Springer-Verlag, 1992, xvii + 556 p., US $298 (ISBN o-387-54460-7). Early Organic Evolution is the proceedings of the ninth Alfred Wegener Conference, the final meeting of IGCP Project 157 held in
Department of Geological Sciences The Ohio State University Columbus, OH 43210, USA
Marine Sciences Program University of North Carolina Chapel Hill, NC 27599
Carry D. McKenzie
Christopher S. Martens
Germany in 1988. Over the past 15 years, Project 157 has promoted the blending of organic geochemistry, economic geology, and evolutionary biology. This IGCP publication covers a diverse set of topics and truly reflects the interdisciplinary nature of the field of early organic evolution. Five sections divide the book into ( 1) Precambrian weathering and paleosols, (2) organic matter in Precambrian and