1. Introduction.- 2. Taxonomy and Species Features.- 2.1 Introduction.- 2.2 Species List.- 2.2.1 Spinose Planktonic Foraminifera.- 2.2.2 Non-spinose Planktonic Foraminifera.- 3. Collecting and Culture Methods.- 3.1 Introduction.- 3.2 Collection for Ecological Studies.- 3.3 Fixation and Storing of Samples.- 3.4 Laboratory Preparations.- 3.5 Collection for Physiological and Ecological Studies.- 3.5.1 Net Collection.- 3.5.2 SCUBA Collection.- 3.6 Isolation and Preparation for Maintenance Culture.- 3.7 Maintenance Cultures.- 3.8 Monitoring Vitality and Growth of the Cultures.- 3.9 Feeding Techniques.- 3.9.1 Algal Prey.- 3.9.2 Animal Prey.- 3.10 Cataloguing and Storing Shells.- 3.11 Summary.- 4. Cellular Ultrastructure.- 4.1 Introduction.- 4.2 Fixation of Planktonic Foraminifera for Fine Structure Analysis.- 4.3 Cytoplasmic Streaming.- 4.4 Peripheral Cytoplasm and Rhizopodial Morphology.- 4.4.1 Cytoskeletal Structures.- 4.4.2 Filaments.- 4.5 Fine Structure of Cytoplasmic Organelles.- 4.5.1 Nucleus.- 4.5.2 Mitochondria.- 4.5.3 Peroxisomes.- 4.5.4 Endoplasmic Reticulum, Golgi Complex, and Vacuolar System.- 4.5.5 Fibrillar Bodies.- 4.5.6 Lipids and Various Cytoplasmic Inclusions.- 4.6 Comparative Fine Structure Data of Benthic and Planktonic Species.- 4.7 Comparative Fine Structure of Planktonic Foraminifera and Radiolaria.- 4.8 Summary.- 5. Host and Symbiont Relationships.- 5.1 Introduction.- 5.2 Symbiosis, Commensalism and Parasitism.- 5.3 Symbiont Morphology and Structural Association with Host.- 5.3.1 Dinoflagellate Symbiont Fine Structure.- 5.3.2 Chrysophycophyte Symbiont Fine Structure.- 5.4 Symbiont and Host Physiological Interactions.- 5.5 Origin of Symbionts.- 5.6 Major Features of Algal Symbionts.- 5.7 Summary.- 6. Trophic Activity and Nutrition.- 6.1 Introduction.- 6.2 Natural Prey.- 6.3 Laboratory Studies of Trophic Activity.- 6.3.1 Prey Acceptance and Rate of Digestion.- 6.3.2 Cannibalism.- 6.3.3 Fine Structure Studies of Prey Capture and Digestion.- 6.3.4 Trophic Activity and Longevity.- 6.3.5 Laboratory Studies of Omnivorous Feeding.- 6.4 Prey Abundance and Foraminiferal Distribution.- 6.5 Predators on Planktonic Foraminifera.- 6.6 Comparative Data with Benthic Foraminifera and Radiolaria.- 6.7 Summary.- 7. Reproduction.- 7.1 Introduction.- 7.2 Gametogenesis.- 7.2.1 Light Microscopic Data.- 7.2.2 Fine Structure Data.- 7.3 Morphological Changes during Gametogenesis.- 7.4 Reproductive Cycles.- 7.5 Comparisons with Benthic Foraminifera and Radiolaria.- 7.6 Summary.- 8. Shell Ontogeny.- 8.1 Introduction.- 8.2 Ontogenetic Concept for Spinose Species.- 8.2.1 Five Stage Concept.- 8.2.2 Ontogeny of Globigerinoides sacculifer.- 8.3 Variations in Developmental Morphology of Spinose Species.- 8.4 Variations in Developmental Morphology of Non-spinose Species.- 8.5 Quantitative Ontogeny.- 8.6 Coiling Directions.- 8.7 Taxonomic Applications.- 8.8 Summary.- 9. Shell Architecture.- 9.1 Introduction.- 9.2 Chamber Deposition and Pore Formation.- 9.2.1 Chamber Formation in Non-spinose Species.- 9.2.2 Pore Formation and Wall Thickening.- 9.2.3 Keel Development.- 9.2.4 Pustule Formation.- 9.3 Chamber Formation in Spinose Species.- 9.3.1 Spine Types.- 9.4 Wall Thickening and Gametogenic Calcification.- 9.5 Physiological Mechanism and Rates of Calcification.- 9.6 Organic Composition of the Calcitic Wall.- 9.7 Resorption and Repair Processes.- 9.8 Abnormal Shell Growth.- 9.9 Summary.- 10. Ecology.- 10.1 Introduction.- 10.2 Statistical Treatment and the Transfer Function.- 10.3 Stable Isotopes.- 10.4 Distributional Pattern of Planktonic Foraminifera.- 10.4.1 Horizontal Distribution.- 10.4.2 Seasonal Distribution.- 10.4.3 Vertical Distribution.- 10.4.4 Patchiness and Daily Vertical Migration.- 10.4.5 General Sea Surface Temperature in the Past.- 10.5 Population Dynamics.- 10.5.1 Reproductive Strategies.- 10.5.1.1 Lunar Periodicity.- 10.5.1.2 Annual Periodicity.- 10.5.2 Water Mass Boundary Effects.- 10.6 Experimental Studies.- 10.7 Summary.- 11. Sedimentation - Settlement of Shells.- 11.1 Introduction.- 11.2 Shells Released by Reproduction and Juvenile Mortality.- 11.3 Aggregates - Sedimentation.- 11.4 Predation.- 11.5 Residence Time and Sinking Velocity.- 11.6 Seasonal Fluctuations in the Settlement.- 11.7 Dissolution in the Deep Water.- 11.8 Summary.- 12. Concluding Remarks.- 12.1 Effects Influencing the Isotopic Signal.- 12.1.1 Temperature Effect.- 12.1.2 GlacialEffect.- 12.1.3 Water Mass Effect.- 12.1.4 VitalEffect.- 12.1.5 Selective Production.- 12.1.6 Differential Dissolution.- 12.2 Carbon Isotopes.- 12.3 Summative Perspective.- 13. References.- 14. Glossary.- 15. Index.

Modern Planktonic Foraminifera

[1] Paired Mg/Ca and δ18O measurements on planktonic foraminiferal species (G. ruber white, G. ruber pink, G. sacculifer, G. conglobatus, G. aequilateralis, O. universa, N. dutertrei, P. obliquiloculata, G. inflata, G. truncatulinoides, G. hirsuta, and G. crassaformis) from a 6-year sediment trap time series in the Sargasso Sea were used to define the sensitivity of foraminiferal Mg/Ca to calcification temperature. Habitat depths and calcification temperatures were estimated from comparison of δ18O of foraminifera with equilibrium calcite, based on historical temperature and salinity data. When considered together, Mg/Ca (mmol/mol) of all species, except two, show a significant (r = 0.93) relationship with temperature (T °C) of the form Mg/Ca = 0.38 (±0.02) exp 0.090 (±0.003)T, equivalent to a 9.0 ± 0.3% change in Mg/Ca for a 1°C change in temperature. Small differences exist in calibrations between species and between different size fractions of the same species. O. universa and G. aequilateralis have higher Mg/Ca than other species, and in general, data can be best described with the same temperature sensitivity for all species and pre-exponential constants in the sequence O. universa > G. aequilateralis ≈ G. bulloides > G. ruber ≈ G. sacculifer ≈ other species. This approach gives an accuracy of ±1.2°C in the estimation of calcification temperature. The ∼9% sensitivity to temperature is similar to published studies from culture and core top calibrations, but differences exist from some literature values of pre-exponential constants. Different cleaning methodologies and artefacts of core top dissolution are probably implicated, and perhaps environmental factors yet understood. Planktonic foraminiferal Mg/Ca temperature estimates can be used for reconstructing surface temperatures and mixed and thermocline temperatures (using G. ruber pink, G. ruber white, G. sacculifer, N. dutertrei, P. obliquiloculata, etc.). The existence of a single Mg thermometry equation is valuable for extinct species, although use of species-specific equations will, where statistically significant, provide more accurate evaluation of Mg/Ca paleotemperature.

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Calibration of Mg/Ca thermometry in planktonic foraminifera from a sediment trap time series

[1] Mid-Cretaceous (Barremian-Turonian) plankton preserved in deep-sea marl, organic-rich shale, and pelagic carbonate hold an important record of how the marine biosphere responded to short- and long-term changes in the ocean-climate system. Oceanic anoxic events (OAEs) were short-lived episodes of organic carbon burial that are distinguished by their widespread distribution as discrete beds of black shale and/or pronounced carbon isotopic excursions. OAE1a in the early Aptian (∼120.5 Ma) and OAE2 at the Cenomanian/Turonian boundary (∼93.5 Ma) were global in their distribution and associated with heightened marine productivity. OAE1b spans the Aptian/Albian boundary (∼113–109 Ma) and represents a protracted interval of dysoxia with multiple discrete black shales across parts of Tethys (including Mexico), while OAE1d developed across eastern and western Tethys and in other locales during the latest Albian (∼99.5 Ma). Mineralized plankton experienced accelerated rates of speciation and extinction at or near the major Cretaceous OAEs, and strontium isotopic evidence suggests a possible link to times of rapid oceanic plateau formation and/or increased rates of ridge crest volcanism. Elevated levels of trace metals in OAE1a and OAE2 strata suggest that marine productivity may have been facilitated by increased availability of dissolved iron. The association of plankton turnover and carbon isotopic excursions with each of the major OAEs, despite the variable geographic distribution of black shale accumulation, points to widespread changes in the ocean-climate system. Ocean crust production and hydrothermal activity increased in the late Aptian. Faster spreading rates [and/or increased ridge length] drove a long-term (Albian–early Turonian) rise in sea level and CO2-induced global warming. Changes in ocean circulation, water column stratification, and nutrient partitioning lead to a reorganization of plankton community structure and widespread carbonate (chalk) deposition during the Late Cretaceous. We conclude that there were important linkages between submarine volcanism, plankton evolution, and the cycling of carbon through the marine biosphere.

Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid-Cretaceous

The equator to high southern latitude sea surface and vertical temperature gradients are reconstructed from oxygen isotope values of planktonic and benthic foraminifers for the following five time intervals: late Paleocene, early Eocene, early middle Eocene, late Eocene, and early Oligocene. Paleotemperatures are calculated using standard oxygen isotope/temperature equations with adjustments to account for (1) variations in sea water δ18O related to changes in global ice volume over time and (2) latitudinal gradients in surface water δ18O. These reconstructions indicate that sea-surface temperatures (SST) of the Southern Oceans in the early Eocene were as high as 15°C, whereas temperatures during the late Paleocene and early middle Eocene reached maximum levels of 10°–12°C. By the late Eocene and early Oligocene high latitude SST had declined to 6 and 4°C, respectively. For most of the early Paleogene, low latitude sub-tropical temperatures remained constant and well within the range of Holocene temperatures (24°ndash;25°C) but by the late Eocene and early Oligocene declined to values in the range of 18° to 22°C. The late Paleogene apparent decline in tropical temperatures, however, might be artificial because of dissolution of near-surface foraminifera tests which biased sediment assemblages toward deeper-dwelling foraminifera. Moreover, according to recent plate reconstructions, it appears that the majority of sites upon which the late Eocene and early Oligocene tropical temperatures were previously established were located either in or near regions likely to have been influenced by upwelling. Global deepwater temperature on average paralleled southern ocean SST for most of the Paleogene. We speculate based on the overall timing and character of marine sea surface temperature variation during the Paleogene that some combination of both higher levels of greenhouse gases and increased heat transport was responsible for the exceptional high-latitude warmth of the early Eocene.

Evolution of Early Cenozoic marine temperatures

A detailed δ 18 O and δ 13 C stratigraphy has been generated from analysis of well-preserved Albian–early Maastrichtian foraminifera from Deep Sea Drilling Project (DSDP) Sites 511 and 327 (Falkland Plateau; ≈58° S–62° S paleolatitude) in the southern South Atlantic, and Cenomanian and Coniacian–Santonian foraminifera from DSDP Site 258 (Naturaliste Plateau; ≈58° S paleolatitude) in the southern Indian Ocean. These results, when combined with previously published Maastrichtian stable isotope data from Ocean Drilling Program (ODP) Site 690 (Weddell Sea, ≈65° S paleolatitude), provide new insight into the climatic and oceanographic history of the southern high latitudes during middle–Late Cretaceous time. The planktonic foraminifer δ 18 O curves reveal a gradual warming of surface waters from the Albian through the Cenomanian followed by extremely warm surface waters from the Turonian through the early Campanian. Long-term cooling of surface waters began in the late early Campanian and continued through the end of the Maastrichtian. The benthic foraminifer δ 18 O record generally parallels changes in the oxygen isotopic curves defined by shallow-dwelling planktonic foraminifera. The vertical oxygen and carbon isotopic gradients were relatively low during the Albian–Cenomanian, high from the Turonian–early Campanian, and then low during the late Campanian and Maastrichtian. Foraminiferal oxygen isotopic data from published sources and this study are averaged for each site, corrected for latitudinal changes in salinity based on modern-day surface-water values, and plotted versus paleolatitude for the late Albian, Coniacian–Santonian, and late Maastrichtian. Differences between lowand high-latitude surface-water paleotemperatures are estimated at ≈14 ° C during the late Albian and late Maastrichtian, but the Coniacian–Santonian reconstruction reveals only a 0–4 ° C latitudinal temperature gradient. Uncertainty regarding Cretaceous salinity gradients and possible diagenetic alteration of δ 18 O values introduce error into our estimates of paleolatitudinal thermal gradients; however, apparent low equator-to-pole temperature differences could indicate much higher poleward heat transport than at present.

Middle–Late Cretaceous climate of the southern high latitudes: Stable isotopic evidence for minimal equator-to-pole thermal gradients

Seasonal changes in species composition, numbers, mass, size, and isotopic composition of planktonic foraminifera settling into the deep sargasso sea☆

Few studies have been reported on the predatory habits of planktonic foraminifera or on their position in marine food webs. Planktonic foraminifera are large marine Sarcodina possessing a calcium carbonate shell (usually < 1 mm diam.) surrounded by a dense halo of rhizopodia that in some species may increase the cell diameter to 20 mm. Food organisms are snared by the sticky rhizopodia which entangle the prey and draw it into a dense layer of cytoplasm near the shell where digestion occurs (Anderson & Be, 1976). Clearly species survival, their abundance, and their distribution in a region are deter-mined by the availability of food organisms, so that species that prey on a wide variety of organisms have greater survival advantage than those with a more restricted range of prey. Hence, many of the traditionally studied topics in foraminiferal research such as species abundance, survival time, geographical distribution and contribution to calcium carbonate sediments may be significantly determined by foraminiferal trophic activity. A clearer understanding of foraminiferal predation may help to explain ancient and modern assemblages of species and thus contribute to a more systematic interpretation of foraminiferal ecology.

M. Spindler

Papers

Seasonal changes in species composition, numbers, mass, size, and isotopic composition of planktonic foraminifera settling into the deep sargasso sea☆

Trophic activity of planktonic foraminifera

Formation and possible function of annulate lamellae in a planktic foraminifer