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We provide records of relative sea level since A.D. 1500 from two salt marshes in North Carolina to complement existing tide-gauge records and to determine when recent rates of accelerated sea-level rise commenced. Reconstructions were developed using foraminiferabased transfer functions and composite chronologies, which were validated against regional twentieth century tide-gauge records. The measured rate of relative sea-level rise in North Carolina during the twentieth century was 3.0-3.3 mm/a, consisting of a background rate of ~1 mm/a, plus an abrupt increase of 2.2 mm/a, which began between A.D. 1879 and 1915. This acceleration is broadly synchronous with other studies from the Atlantic coast. The magnitude of the acceleration at both sites is larger than at sites farther north along the U.S. and Canadian Atlantic coast and may be indicative of a latitudinal trend. doi: 10.1130/G30352A.1

The authors discuss patterns of species diversity in deep-sea benthic foraminifera. Data from five locations in the Atlantic Ocean were used in the analysis.

Supposed Upper Proterozoic strata in the southwest Taoudeni Basin, Guinea and Senegal, and from the Mauritanide fold belt, Mauritania, have yielded mostly poorly preserved small skeletal fossils of metazoan and protistan origin. Problematic, but possible echinoderm material and spicules of the heteractinid sponge Eiffelia dominate the Taoudeni Basin assemblage. The age of the material is not certain but the paleontologic data suggest an Early Cambrian age for the stratigraphically lowest faunas, and a Middle Cambrian age is possible for the stratigraphically highest collections.

The tropics are often evoked as a center for species origination. Foraminifera are one of the few groups of organisms with a fossil record sufficient to establish the geographic origin of species. The modern foraminiferal biota on the Atlantic continental margin of North America contains 259 species with a fossil record. The worldwide geographic origin of these species was documented using museum collections. Only 14% of these species originated in the subpolar regions, whereas nearly equal proportions originated in the temperate regions (46%) and tropical regions (40%). Moreover, the majority (76%) of species originating in the temperate regions now also occur in the modern tropical biota. These foraminiferal data suggest that, in contrast to the center of origin hypothesis, the biota of temperate and tropical latitudes act in concert with a substantial species interchange between them.

The foraminifera, shelled protozoans usually less than 1 mm in diameter, exhibit a wide variety of morphology (Figure 1). Benthic foraminifera are distributed in all marine environments from marshes and [...]

Tropical diversity has generally exceeded temperate diversity in the present and at points in the past, but whether measured differences have remained relatively constant through time has been unknown. Here we examine tropical vs. temperate diversities from the Neogene to Recent using the within-habitat diversity measure Fisher's alpha of Cenozoic benthic foraminifera from the temperate Central Atlantic Coastal Plain and the tropical Central American Isthmus. During the Neogene, the mean value of alpha at temperate latitudes increased 1.4 times or 40%, whereas in the tropics it increased 2.1 times or 106%. Thus, while both areas exhibit an increase of diversity with time, past differences in the rate of increase have generated a more pronounced gradient today (164%) than existed in the Miocene (80%). These data disagree with the suggestion that the world reached an equilibrium number of species during the Paleozoic and demonstrate the need to consider both temperate and tropical components in global diversity assessments.

Foraminiferal communities in the Cenozoic shelf deposits of the North American Atlantic Coastal Plain exhibit little unity during almost 55 million years of successive transgressions and regressions. Transgression communities are composed of a dynamic mixture of immigrants and newly evolved species. During regressions, species within these communities either became extinct or emigrated. Some emigrants returned during subsequent transgressions, but many did not. The neritic species of the Atlantic and Gulf continental margins constitute a species pool. Immigrants and emigrants transferred into and out of the species pool, while extinctions and originations repeatedly altered its species composition. While the results indicate a lack of local community unity, at the same time they demonstrate the necessity of a species pool to sustain species diversity., Some ecological communities have been regarded as a kind of superorganism or unit wherein the component species are closely associated by numerous biotic interactions. Others have been considered as a [...]

Agglutinated forminifera have been recovered from siltstones in the Walidiala Valley, Taoudeni Basin, West Africa. Associated faunas suggest an Early Cambrian age for these strata. These now earliest known unequivocal formainifera help constrain hypotheses concerning the origin of skeletalization at the beginning of the Phanerozotic., DISCUSSIONS CONCERNING THE APpearance of skeletonization near the base of the Cambrian [about 550 Ma (million year ago)] [1] are often restricted to metazoans and take little account of the [...]

Geographic Origin of Benthic Foraminiferal Species THE CENTERS OF ORIGIN OF SPECIES have been discussed in the literature of biogeography and evolution for over a century. The classic scenario maintains [...]

Analysis of species durations is useful for understanding the interplay of ecological and evolutionary forces (1). Among marine organisms the benthic foraminifera are widely distributed, and they have a well [...]