Major Faunal Changes Research Articles

Prospects for the future of pink salmon in three oceans: From the native Pacific to the novel Arctic and Atlantic

AbstractWhile populations of other migratory salmonids suffer in the Anthropocene, pink salmon (Oncorhynchus gorbuscaSalmonidae) are thriving, and their distribution is expanding both within their natural range and in the Atlantic and Arctic following introduction of the species to the White Sea in the 1950s. Pink salmon are now rapidly spreading in Europe and even across the ocean to North America. Large numbers of pink salmon breed in Norwegian rivers and small numbers of individuals have been captured throughout the North Atlantic since 2017. Although little is known about the biology and ecology of the pink salmon in its novel distribution, the impacts of the species' introduction are potentially highly significant for native species and watershed productivity. Contrasts between pink salmon in the native and extended ranges will be key to navigating management strategies for Atlantic nations where the pink salmon is entrenching itself among the fish fauna, posing potential threats to native fish communities. One key conclusion of this paper is that the species' heritable traits are rapidly selected and drive local adaptation and evolution. Within the Atlantic region, this may facilitate further establishment and spread. The invasion of pink salmon in the Atlantic basin is ultimately a massive ecological experiment and one of the first examples of a major faunal change in the North Atlantic Ocean that is already undergoing rapid changes due to other anthropogenic stressors. New research is urgently needed to understand the role and potential future impacts of pink salmon in Atlantic ecosystems.

The Cretaceous/Tertiary boundary event in Tibet

The Cretaceous/Tertiary boundary in the Gamba and Tingri regions of Tibet occurs between the Zongshan and Jidula Formations. Arenaceous facies similar to those of the Jidula Formation are widespread in Tibet and Pakistan; collectively, these represent the diachronous deposits of the Latest Cretaceous-Early Tertiary regression. Major faunal changes took place in Tibet during the Late Cretaceous. Ali of the Cretaceous ammonoids, planktonic and benthonic foraminifera, rudistid and inoceramid bivalves became extinct over the Campanian Maastrichtian interval in a stepwise pattern, with abrupt Late Campanian and Late Maastrichtian extinction events (Tabs. 3, 4). A large number of new taxa appeared during the Danian (Tabs. 3, 4). These faunal changes in the shallow-water marine facies of Tibet demonstrate that this region was not isolated from major global faunal changes taking place in the Cretaceous/Tertiary boundary mass extinction interval.

Latest Albian-earliest Turonian deep-water agglutinated foraminifera in the Bottaccione section (Gubbio, Italy) - Biostratigraphic and palaeoecologic implications.

Using semi-quantitative methods, the distribution of deep-water agglutinated foraminifera (DW AF) was analyzed within the Latest Albian-earliest Turonian pelagic limestones of the famous Bottaccione standard section. The characteristic bathyal communities include forms of purely agglutinated "flysch-lype" assemblages and elements which are typical of Upper Cretaceous abyssal environments of the North Atlantic. Well-established planktonic foraminiferal and calcareous nannofossil zonations allowed to directly gauge the stratigraphic ranges of DW AF, contributing to a better chronostratigraphic calibration of a deep-water agglutinated foraminiferal zonation. Differences in ranges of sorne biostratigraphic marker species were observed. The distribution of morphogroups enabled us to interpret levels of oxygenation and organic input. The effects of the Cenomanian-Turonian boundary event (here represented by the ichtyolithic-bituminous-radiolaritic Livello Bonarelli) on the DW AF were explored in detail. A major faunal change in agglutinated foraminiferal communities consisting of a marked decrease in faunal density and species richness was recognized in the middle of the Rotalipora cushmani Zone coinciding with a marked change in sedimentary regimes and related to extensive oxygen depletion on the sea bottom.

PALEONTOLOGY AND EVOLUTIONARY LINEAGES OF THE DIAGNOSTIC BENTHIC FORAMINIFERAL GENUS ORTHOKARSTENIA

This work is focused on the members of the Late Cretaceous-Early Paleogene (K-Pg) diagnostic benthic foraminiferal genus Orthokarstenia which is regionally important in paleontology and stratigraphic correlations. The large number of tests available and the rapid morphologic changes, offer an opportunity to study evolutionary changes in these foraminiferal taxa over a time span of about 25 m. y. (75-50 Ma). Six species of the genus Orthokarstenia are presented: O. applinae, O. eleganta, O. esnehensis, O. higazyi, O. nakkadyi and O. oveyi, which were recorded in eight localities in the Southern Tethys: Nigeria, Tunisia, Egypt (central and north Africa), Jordan, Saudi Arabia, UAE, Iran and Pakistan (southwest Asia). Evolutionary changes of them are indicated by such criteria, such as changes in the test-size, chambers arrangement, type of sutures, periphery or surface ornamentation. These changes help to define the major faunal change of the Campanian/Maastrichtian (C/M) boundary, K/Pg boundary, and can used in biostratigraphic subdivisions and correlations based on benthic foraminifera, beside planktic foraminiferal zonation.

Recent environmental change in the Kosterhavet National Park marine protected area as reflected by hydrography and sediment proxy data

The Koster Trench is the deepest part of the Kosterfjord (Skagerrak, North Sea), which stretches southward along the west coast of Sweden. Since 2009 Kosterfjord has been included in the Marine Protected Area Kosterhavet National Park. To effectively manage national parks, long-term time series of ecological data are needed and those can be derived from local sediment archives. In this study we present multiproxy geochemical (bulk TOC, C/N and heavy metals) and micropaleontological (dinoflagellate cysts, selected palynomorphs and benthic foraminifera) data from a sediment core taken in the southern part of the Koster Trench. Radiometric dating by 210Pb and 137Cs shows that the core archived the environmental changes that took place between 1988 and 2012. The TOC, heavy metals and foraminiferal indices indicate mainly high to good Ecological Quality Status, with moderate ecological quality for arsenic concentrations. Dinoflagellate cysts suggest a major change occurring in the upper water column around 2002. The cysts of Pentapharsodinium dalei peak around 1992 and show overall slightly higher relative abundances between 1988 and 2002. Increased abundance of Biecheleria baltica cysts, heterotrophic species, oligotrichids, pollen and spores characterise the upper core part deposited from 2002 to 2012. Also, there is a clear increase of Alexandrium cysts in the top of the core (~2008–2012). Benthic foraminifera show a major faunal change reflected in a significant increase of agglutinated species (mainly Textularia earlandi) from 2007 towards present day, while the lower part of the core (1988–2007) is dominated by calcareous species. Overall, the changes demonstrated by the dataset suggest an increased freshwater input or a higher river/land runoff, as supported by climatic and hydrographical data showing increased precipitation over the study area, decreasing salinity, and an increasing trend in particulate organic carbon in the surface waters. These changes, in combination with trawling activities, which have been moved to the deepest part of the trench since 2009, seem to favour dinoflagellate and benthic foraminiferal species with mixotrophic and omnivorous feeding strategies. Similar to the dinocysts, calculated foram-AMBI and NQIforam indices show a shift around 2002 suggesting that environmental changes occurring in the study area are likely linked to darkening of coastal waters.

Punctuationlism and Gradualistic Evolutionary Trends of Eight Phylogenetic Lineages of Maastrichtian to Eocene and Recent Benthic Foraminifera from the Tethys

Minor differences in the morphology of the test, wall structure, arrangement of chambers and apertures, size are recognized as being of decisive specific or subspecific value. Twenty four phylogenetic lineages were produced by puncuated equilibrium and gradualistic evolutionary trends which observed within 50 benthic foraminiferal species and subspecies belonging to 18 genera throughout the Maastrichtian to Priabonian forms in Tethys as well as one recent species by the present authors and others. In this study, new eight lineages are presented: Clavulina parisiensis d'Orbigny ˃ C. pseudoparisensis Anan, Laevidentalina granti (Plummer) ˃ L. salimi Anan, Lenticulina carinata (Plummer) ˃ L. turbinata (Plummer) ˃ L. chitanii (Yabe and Asano), Percultazonaria ameeri Anan ˃ P. allami Anan, Percultazonaria alii Anan ˃ P. longiscata (Nakkady), Percultazonaria wadiarabensis (Futyan) ˃ P. tuberculata (Plummer), Palmula woodi undulata Nakkady ˃ P. w. woodi Nakkady, Gavelinella b. brotzeni Said and Kenawy ˃ G. brotzeni paleocenica Said and Kenawy. These lineages help, not only to define the major faunal changes at the Cretaceous/Tertiary (K/T) and the Paleocene/Eocene (P/E) boundaries, but also to emphasis the stratigraphic importance of them in different localities in the Tethys.

Pattern and Processes of the Mammalian Turnover of the Arikareean in the Northern Rocky Mountains

ABSTRACT The later part of the Oligocene (Arikareean North American Land Mammal Age) was a time of major faunal change in North America. It is during this time period that archaic mammalian faunas dominated by extinct families started giving way to more modern faunas, including families still extant today. Studies of this faunal transition have so far focused on the Great Plains and the Columbia Plateau. I present here the first quantitative analysis for the northern Rocky Mountains, combining four new radioisotopic dates and almost 1,000 specimens from a series of vertebrate microfossil assemblages through the Cabbage Patch beds of Montana. I demonstrate that the rise of modern mammalian communities was already under way in the Rocky Mountains 30 million years ago, at the base of the beds. However, the major faunal turnover event took place ca. 28 million years ago, at the transition from the lower to the middle units of the Cabbage Patch beds, and led to the disappearance of many archaic mammal taxa that dominated the start of the Arikareean. This event was synchronous across the Great Plains, the Rocky Mountains, and the Columbia Plateau and was driven by the diversification of descendants of immigrants from Eurasia that had reached North America through Beringia. Holdovers from archaic mammalian faunas persist into the upper unit of the beds later than in the Great Plains, but not the Columbia Plateau. Future biogeographic analyses will be necessary to assess the role of topography and environmental change in the rise of modern mammalian communities.

Response of macrobenthic communities to the Toarcian Oceanic Anoxic Event in northeastern Panthalassa (Ya Ha Tinda, Alberta, Canada)

In the Early Jurassic, the late Pliensbachian through early Toarcian interval exhibits significant environmental perturbations and biotic extinctions. This study documents the macrobenthic community during this interval in a region that has previously received comparatively little study: northeastern Panthalassa. The relicts of benthic communities from the Ya Ha Tinda Lagerstätte (Fernie Formation) in Alberta, Canada are primarily composed of bivalves and brachiopods, and exhibit taxonomic and ecological similarities with coeval black shale faunas from Europe.At Ya Ha Tinda, the initiation of the carbon isotope excursion that occurred during the Toarcian Oceanic Anoxic Event (T-OAE) is coincident with major faunal change. The pre-T-OAE community is composed of large epifaunal suspension-feeders (bivalves and brachiopods), lobsters, crinoids, and burrowing organisms represented as trace fossils. The onset of the isotope excursion coincided with a wholesale turnover of bivalve and brachiopod genera as well as with a significant diminution in body size of the community members as a whole. The intra-T-OAE community largely consisted of opportunistic, low-oxygen-tolerant benthic taxa that colonized the seafloor periodically along with some facultatively pseudoplanktonic taxa. Unlike the contemporary deposits in Europe, there is no sign of recovery at Ya Ha Tinda in the middle Toarcian Planulata Ammonite Zone; abundance, richness, and functional diversity of benthic taxa remained extremely low and the size of community members remained small. The primary stress on this system is interpreted to have been oxygen limitation. The minimal ecological effect on the benthic community at the Pliensbachian-Toarcian stage boundary and delayed recovery from the T-OAE of the benthos are in marked contrast to the pelagic record from northeastern Panthalassa. This suggests a decoupling of the benthic and pelagic communities in this region during the Early Jurassic.

Diversity and faunal changes in the latest Cretaceous dinosaur communities of southwestern Europe

Characterization of macroecological patterns for latest Cretaceous dinosaur communities is essential to understand how those faunas were changing during the run-up to the Cretaceous-Paleogene extinction event, and thus the cause of the extinction. Outside of the well-studied latest Cretaceous dinosaurs of North America, southwestern Europe (France, Spain and Portugal) preserves one of the richest end-Cretaceous dinosaur fossil records, as it has produced hundreds of dinosaur fossil localities. We compiled a comprehensive database of all dinosaur fossil occurrences from the uppermost Cretaceous of the Ibero-Armorican region and analyze it statistically, providing the first numerical study of the ecological and taxonomic diversities of these communities. Our study corroborates previous work that has identified a major faunal change in the latest Cretaceous terrestrial vertebrate assemblages, and places this event around the C31r-C31n reversal, in the early late Maastrichtian (c. 69 Ma). Significant differences in ecological diversity metrics (dominance, Shannon and Simpson) characterize the pre- and post-turnover assemblages. The turnover event, therefore, did not only lead to a taxonomic replacement but also important reorganizations in the structure of dinosaur communities. Herbivorous dinosaurs suffered the most dramatic alterations across the turnover, in terms of relative dominances, by shifting their contributions within the communities (hadrosauroids replacing titanosaurids as the dominant taxon in the medium-to large-bodied herbivore niche) or even disappearing (rhabdodontids and nodosaurids). The carnivores apparently maintained similar relative abundances before and after the turnover, and the relative proportions between carnivorous and herbivorous taxa remained static through time. Further improvement of the present database might allow for the identification of new ecological patterns, and higher-resolution comparison with the North American records.

Sediment core fossils in ancient Lake Ohrid: testing for faunal change since the Last Interglacial

Abstract. Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harbouring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic subdivision comprising the basal succession of core Co1200 between 181.5–263 cm, appeared solid, greyish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated and the agreement between sediment and palaeontological proxies was tested. The study also aims at investigating major faunal changes since the Last Interglacial and searching for signs of extinction events. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m water depth) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid.

Holocene ostracod palaeobiogeography of the Seto Inland Sea, Japan: impact of opening of the strait

Abstract. In this study, published Holocene ostracod data for Osaka, Hiroshima, and Iyo-nada Bays within the Seto Inland Sea (SIS), Japan, are re-examined. Five major faunal changes are recognized at different stratigraphic horizons (Horizons 1–5) in the Holocene sedimentary record. Horizons 1 and 5 (faunal changes) were most likely triggered by the respective openings of the Bisan-seto (and resulting formation of the SIS) and Akashi Straits. Three other major faunal changes, at Horizons 2–4, may also be linked to the opening of straits and resulting formation of bays, although the exact nature of these events is less certain. This re-examination indicates that the opening of straits extensively affected the benthic inner-bay community during the Holocene transgression in the SIS. Further high-resolution studies are needed for confirmation of faunal changes triggered by opening of straits.

Persistent depositional sequences and bioevents in the Eifelian (early Middle Devonian) of eastern Laurentia: North American evidence of the Kačák Events?

Abstract The late Eifelian–earliest Givetian interval (Middle Devonian) represents a time of significant faunal turnover in the eastern Laurentia and globally. A synthesis of biostratigraphic, K-bentonite and sequence stratigraphic data indicates that physical and biotic events in the Appalachian foreland basin sections in New York are coeval with the predominantly carbonate platform sections of southern Ontario and Ohio. The upper Eifelian ( australis to ensensis conodont zones) Marcellus Subgroup in New York comprises two large-scale (3rd-order) composite depositional sequences dominated by black shale, which are here assigned to the Union Springs and Oatka Creek Formations. The succession includes portions of three distinctive benthic faunas or ecological–evolutionary sub-units (EESUs): ‘Onondaga’, ‘Stony Hollow’ and ‘Hamilton’. In the northern Appalachian Basin in New York, the boundaries of these bioevents show evidence of abrupt, widespread extinctions, immigration and ecological restructuring. In the Niagara Peninsula of Ontario and from central to northern Ohio, the same sequence stratigraphic pattern and bioevents are recognized in coeval, carbonate-dominated facies. The correlations underscore a relatively simple pattern of two major sequences and four subsequences that can be recognized throughout much of eastern Laurentia. Moreover, the biotic changes appear to be synchronous across the foreland basin and adjacent cratonic platform. However, the degree of change differs substantially, being less pronounced in carbonatedominated mid-continent sections. Finally, we make the case that the two major faunal changes align with regional sequence stratigraphic patterns as well as with the global Kačák bioevents.

Palaeontologic and biogeochemical characterization of the Cyrtograptus lundgreni event in the black shales of eastern Mid‐Sardinia, Italy

A succession of biotic and geochemical changes that occurred during the Cyrtograptus lundgreni Event (Late Wenlock) have been recorded from the ‘pelagic’ black-shales in the Goni section, eastern mid-Sardinia, Italy. The studied interval encompasses the Cyrtograptus rigidus to Pristiograptus dubius-Gothograptus nassa zones. The fossil association includes graptolites, chitinozoans and microplankton i.e. probable linings of agglutinated foraminifera and radiolaria capsular membranes. Analysis of the chitinozoan distribution revealed a succession of several chitinozoan associations with low species diversity and dominated by opportunistic species. Three chitinozoan faunal turnovers and three extinction events have been recorded. Two of them coincide with graptolite extinctions whereas one probably is of local significance. Disappearance of the chitinozoan and microplankton associations occurred during four consecutive graptolite zones. Geochemical data (trace elements analysis) showed significantly higher (up to c. 100%) values for Co and Cd in the sedimentary organic matter (SOM) than in the whole rock samples. Possible relationships between peaks of metal enrichment, the major faunal changes among chitinozoans, extinction events among chitinozoans and graptolites and, to a certain extent, oceanic events may be inferred. The first extinction datum is older that those occurring in Gotland, Sweden and Thüringen, Germany and is so far considered to be of local significance. The second extinction datum of Sardinia can be matched with Datum 1 of Gotland and Thüringen. A close correlation between the third extinction datum of Sardinia and Datum 2 of Thüringen and Gotland reinforces the importance of these events at global scale.

Radiolarian faunal turnover and paleoceanographic change around Eocene/Oligocene boundary in the central equatorial Pacific, ODP Leg 199, Holes 1218A, 1219A, and 1220A

Continuous Eocene through Oligocene sedimentary sedimentary sections were obtained at Holes 1218A, 1219A, and 1220A drilled during Leg 199 of the Ocean Drilling Program in the central equatorial Pacific. Quantitative analysis of radiolarian assemblages between the upper Eocene through lower Oligocene sedimentary successions revealed that major faunal changes of radiolarians occurred in the late Eocene (35.5–35.7 Ma; Subchron C16n1), around the Eocene/Oligocene boundary (33.7–33.8 Ma; upper Subchron C13r) and in the early Oligocene (30.9–31.3 Ma; uppermost Subchron C12r). The faunal change in the late Eocene is characterized by a stepwise decrease of tropical Eocene species and an increase in cosmopolitan, probably cool-water-tolerant, radiolarians; however, without a significant change in species diversity and radiolarian accumulation rates. The stratigraphic level of this late Eocene turnover came after the late Eocene impact event, and may have been more related to global cooling and associated oceanographic changes than to asteroid impact. The turnover around the Eocene/Oligocene boundary, corresponding to the Oi-1 event, is the most critical during the Eocene–Oligocene transition. Many biotic events such as a sudden drop of species diversity, an increase in the cosmopolitan radiolarian group, a large number of species turnovers, and a drop in radiolarian accumulation rates occurred at or just above this level. Together these indicators suggest a major restructuring of radiolarian assemblages from the high diversity Eocene fauna to a low diversity Oligocene one. The third turnover event within early Oligocene is represented by a replacement of dominant species with a sudden decrease in radiolarian accumulation rates. However, this Oligocene turnover is not consistent with other major δ 18O isotope events, such as Oi-1b and Oi-2.

Radioisotopic and biostratigraphic age relations in the Coast Range Ophiolite, northern California: Implications for the tectonic evolution of the Western Cordillera

The Coast Range ophiolite (CRO) in northern California includes two distinct remnants. The Elder Creek ophiolite is a classic suprasubduction zone ophiolite with three sequential plutonic suites (layered gabbro, wehrlite-pyroxenite, quartz diorite), a mafi c to felsic dike complex, and mafi c-felsic volcanic rocks; the entire suite is cut by late mid-oceanic-ridge basalt (MORB) dikes and overlain by ophiolitic breccia. The Stonyford volcanic complex (SFVC) comprises three volcanic series with intercalated chert horizons that form a submarine volcano enclosed in sheared serpentinite. Structurally below this seamount are melange blocks of CRO similar to Elder Creek. U/Pb zircon ages from plagiogranite and quartz diorites at Elder Creek range in age from 165 Ma to 172 Ma. U/Pb zircon ages obtained from CRO melange blocks below the SFVC are similar (166‐172 Ma). 40 Ar- 39 Ar ages of alkali basalt glass in the upper SFVC are all younger at ≈164 Ma. Radiolarians extracted from chert lenses intercalated with basalt in the SFVC indicate that the sedimentary strata range in age from Bathonian (Unitary Association Zone 6‐6 of Baumgartner et al., 1995a) near the base of the complex to late Callovian to early Kimmeridgian (Unitary Association Zones 8‐10) in the upper part. The SFVC sedimentary record preserves evidence of a major faunal change wherein relatively small-sized, polytaxic radiolarian faunas were replaced by very robust, oligotaxic, nassellarian-dominated faunas that included Praeparvicingula spp. We suggest that CRO formation began after the early Middle Jurassic (172‐180 Ma) collision of an exotic or fringing arc with North America and initiation of a new or reconfi gured east-dipping subduction zone. The data show that the CRO formed prior to the Late Jurassic Nevadan orogeny, probably by rapid forearc extension above a nascent subduction zone. We infer that CRO spreading ended with the collision of an oceanic spreading center ca. 164 Ma, coincident with the oldest high-grade blocks in the structurally underlying Franciscan assemblage. We further suggest that the “classic” Nevadan orogeny represents a response to spreading center collision, with shallow subduction of young lithosphere causing the initial compressional deformation and with a subsequent change in North American plate motion to rapid northward drift (J2 cusp) causing sinistral transpression and transtension in the Sierra foothills. These data are not consistent with models for Late Jurassic arc collision in the Sierra foothills or a back-arc origin for the CRO.

Climate variations, an overlooked factor influencing the recent marine environment. An example from Gullmar Fjord, Sweden, illustrated by benthic foraminifera and hydrographic data

Like most sill fjords, Gullmar Fjord on the Swedish west coast, is subject to periods of stagnation. Deep water is usually renewed annually, but since the late 1970s several low-oxygen events have been documented in the deepest part of the fjord. These events occurred during a time when the North Atlantic Oscillation (NAO) was in a highly positive phase. We investigated how the benthic environment, in the deepest part of the fjord, has varied during the 20th century, using benthic foraminifera and an extensive history of instrumental hydrographic data. The foraminifera have undergone one major faunal change and two minor modifications during this time. The major faunal change occurred in the late 1970s to early 1980s, when the common Skagerrak-Kattegat fauna was replaced by one dominated by the opportunistic, low-oxygen-tolerant species,Stainforthia fusiformis. This major faunal change appears to be related to the severe low-oxygen event in 1979–1980. In the latter part of the 1990s the fauna changed again; the concentration ofS. fusiformis was still high, but other low-oxygen-tolerant species also became important. This minor faunal modification occurred in connection with the 2-yr stagnation period between 1996 and 1998 when a low-oxygenevent evolved, the most severe recorded in Gullmar Fjord. Between 1930 and 1980, there was little faunal variation, and a stable fjord environment is indicated. During this time, negative NAO indexes dominated and climate was more continental, with an increase in winds from the northeast and east. In connection with a climate transition indicated by the NAO index switching from positive to negative, a minor faunal change occurred in the late 1920s to early 1930s: the concentration of the Skagerrak-Kattegat fauna increased markedly in the fjord. The fauna characterizing the positive NAO phase between 1900 and the late 1920s is very different from the present positive NAO fauna. The foraminiferal record laid down between approximately 1914 and 2001 indicates that between 1930 and 1980 Gullmar Fjord was a stable fjord environment. During the last 20 yr, it experienced conditions that were more fluctuating and changing. For the most part, changes in the foraminiferal fauna are caused by changes in the deep-water renewal, their extent and frequency, which in turn are caused by climatic oscillations.

Lothagam: The Dawn of Humanity in Eastern Africa

Lothagam: The Dawn of Humanity in Eastern Africa. Meave G. Leakey and John M. Harris (eds). 2003. Columbia University Press, New York, 688 p., cloth, ISBN 0-231-11870-8. The fossil site known as Lothagam lies west of the southern end of Lake Turkana (formerly Lake Rudolf) in northern Kenya. The Turkana Basin is famous for its paleontological, paleoanthropological, and archeological records from both east and west of this large lake in the eastern part of the rift system. The Plio-Pleistocene outcrops have been the focus of important research in early hominid taxonomy and evolution, subsistence behavior of early hominids, the tempo and mode of evolution in lacustrine gastropods, vertebrate taphonomy, and mammalian faunal turnover, as well as basic systematic paleontology of terrestrial and aquatic vertebrates. Lothagam is a more restricted area (∼60 km2 of outcrop) and its strata are older—late Miocene to early Pliocene, overlain unconformably by Quaternary sands, gravels, and coquinas. Only a handful of African sites document this time period that includes the Messinian salinity crisis and major floral and faunal changes in many parts of the world. Thus, this monograph is a welcome publication for those who work on the later Neogene, and for paleoanthropologists interested in the ecological context of basal hominids. Paleontological work began at Lothagam in 1967 under Bryan Patterson and continued sporadically until 1989, when Meave Leakey and John Harris co-led interdisciplinary research teams in five field seasons to document the geology, geochronology, paleontology, paleoanthropology, and isotope geochemistry of the sediments and faunas. This monograph covers primarily the results of these field seasons from 1989 to 1993, although there are frequent references to results from the earlier field work. The early field seasons retrieved over 500 specimens, including many vertebrate fossils. The fauna documented in the monograph is based on about 1,500 described …

Benthic foraminifera and the late Quaternary (last 150 ka) paleoceanographic and sedimentary history of the Bounty Trough, east of New Zealand

The Bounty Trough, east of New Zealand, lies along the southeastern edge of the present-day Subtropical Front (STF), and is a major conduit via the Bounty Channel, for terrigenous sediment supply from the uplifted Southern Alps to the abyssal Bounty Fan. Census data on 65 benthic foraminiferal faunas (>63 μm) from upper bathyal (ODP 1119), lower bathyal (DSDP 594) and abyssal (ODP 1122) sequences, test and refine existing models for the paleoceanographic and sedimentary history of the trough through the last 150 ka (marine isotope stages, MIS 6-1). Cluster analysis allows recognition of six species groups, whose distribution patterns coincide with bathymetry, the climate cycles and displaced turbidite beds. Detrended canonical correspondence analysis and comparisons with modern faunal patterns suggest that the groups are most strongly influenced by food supply (organic carbon flux), and to a lesser extent by bottom water oxygen and factors relating to sediment type. Major faunal changes at upper bathyal depths (1119) probably resulted from cycles of counter-intuitive seaward-landward migrations of the Southland Front (SF) (north–south sector of the STF). Benthic foraminiferal changes suggest that lower nutrient, cool Subantarctic Surface Water (SAW) was overhead in warm intervals, and higher nutrient-bearing, warm neritic Subtropical Surface Water (STW) was overhead in cold intervals. At lower bathyal depths (594), foraminiferal changes indicate increased glacial productivity and lowered bottom oxygen, attributed to increased upwelling and inflow of cold, nutrient-rich, Antarctic Intermediate Water (AAIW) and shallowing of the oxygen-minimum zone (upper Circum Polar Deep Water, CPDW). The observed cyclical benthic foraminiferal changes are not a result of associations migrating up and down the slope, as glacial faunas (dominated by Globocassidulina canalisuturata and Eilohedra levicula at upper and lower bathyal depths, respectively) are markedly different from those currently living in the Bounty Trough. On the abyssal Bounty Fan (1122), faunal changes correlate most strongly with grain size, and are attributed to varying amounts of mixing of displaced and in-situ faunas. Most of the displaced foraminifera in turbiditic sand beds are sourced from mid-outer shelf depths at the head of the Bounty Channel. Turbidity currents were more prevalent during, but not restricted to, glacial intervals.

An integrated approach to taphonomy and faunal change in the Shungura formation (Ethiopia) and its implication for hominid evolution.

Environmental and faunal changes through time have been recorded for many African Plio-Pleistocene sites. Fossil evidence suggests that there is a continuous, if not uniform, transformation of the fauna and flora from the Pliocene through the end of Pleistocene. However, discerning major biotic turnovers and linking them to global and regional climatic changes have been complicated by many factors, notably taphonomy and discontinuity of the fossil evidence, notwithstanding the considerable work of some researchers (e.g., Vrba, E.S., 1988. Late Pliocene climatic events and hominid evolution, in: Grine, F. (Ed.), Evolutionary History of the "Robust" Australopithecines. De Gruyter, New York, pp. 405-426, Vrba, E.S., 1995. The fossil record of African (Mammalia, Bovidae) in relation to human evolution and paleoclimate, in: Vrba, E.S., Denton, G.H., Partridge, T.C., Burkle, L.H. (Eds.), Paleoclimate and Evolution, with Emphasis on Human Origins. Yale University Press, New Haven, pp. 385-424). A sample of over 22,000 fossils collected by the French Omo Expedition, from the Shungura Formation of Ethiopia, was analyzed using an integrated approach to investigate taphonomic and faunal change patterns. The following results are obtained: (1) Univariate and multivariate studies support continuous faunal change from Member A through Member G of the Shungura sequence; (2) Correspondence analysis (CA) on extant bovids in African game parks shows that bovid tribes and genera are generally characterized by habitat specificity; (3) Taphonomic studies demonstrate that the relative abundance of different skeletal elements varies according to depositional environment; (4) CA on 73 localities of the Shungura Formation and 19 mammalian taxa points to a major faunal change around the base of Member G dated to ca. 2.3 Ma. This transformation is characterized by a change to open and edaphic grassland as a dominant type of environment; (5) This major faunal change correlates in time with the appearance of A. boisei. It is tentatively suggested that this major biome change is associated with an anagenetic speciation from A. aethiopicus to A. boisei.

Depth-related distribution and abundance of seastars (Echinodermata: Asteroidea) in the Porcupine Seabight and Porcupine Abyssal Plain, N.E. Atlantic

The depth-related distribution of seastar (Echinodermata: Asteroidea) species between 150 and 4950 m in the Porcupine Seabight and Porcupine Abyssal Plain is described. 47 species of asteroid were identified from ∼14,000 individuals collected. The bathymetric range of each species is recorded. What are considered quantitative data, from an acoustically monitored epibenthic sledge and supplementary data from otter trawls, are used to display the relative abundance of individuals within their bathymetric range. Asteroid species are found to have very narrow centres of distribution in which they are abundant, despite much wider total adult depth ranges. Centres of distribution may be skewed. This might result from competition for resources or be related to the occurrence of favourable habitats at particular depths. The bathymetric distributions of the juveniles of some species extend outside the adult depth ranges. There is a distinct pattern of zonation with two major regions of faunal change and six distinct zones. An upper slope zone ranges from 150 to ∼700 m depth, an upper bathyal zone between 700 and 1100 m, a mid-bathyal zone from 1100 to1700 m and a lower bathyal zone between 1700 and 2500 m. Below 2500 m the lower continental slope and continental rise have a characteristic asteroid fauna. The abyssal zone starts at about 2800 m. Regions of major faunal change are identified at the boundaries of both upper and mid-bathyal zones and at the transition of bathyal to abyssal fauna. Diversity is greatest at ∼1800 m, decreasing with depth to ∼2600 m before increasing again to high levels at ∼4700 m.