Abstract. New radiolarian-based transfer functions to estimate sea surface temperature (SST) and seasonal range are presented. The transfer functions are based on the approach originated by Imbrie and Kipp [ 1971 ]. The transfer functions differ from previous studies in the following three important ways: (1) extensions to Q-mode factor analysis provide an objective method to cull species in the very diverse radiolarian population; (2) a log transform of the relative abundance data is used to normalize the species percent data; and, (3) rather than writing equations for specific seasons, which are not independent data sets, statistically independent equations are developed to predict mean annual sea surface temperatures as well as seasonal temperature range. One hundred and seventy surface sediment samples from the Pacific Ocean are used to generate the SST and season temperature range transfer functions. All samples were counted using a standardized radiolarian taxonomy. Forty one radiolarian species were used in the final regression equation. Q-mode factor analysis of this data set identified seven assemblages. These assemblages,

An 8.85 m core (No. 9) was taken from Lake Ohrid, Yugoslavia, in August 1973 at a depth of 210 m, approximately 6 km offshore of Gorica, Yugoslavia. The core was sampled at 10-cm intervals and analyzed for moisture, organic and CaCO 3 content, and diatoms. There is a slight but steady decrease of moisture with depth, probably due to sediment compaction. The organic content showed little variation throughout the core (~ = 2.73-+ 0.39% of total weight). The CaCO~ content from 885-110 cm depth also showed little change (~ = 2.32 ± 0.55% of total weight) but increased in the top meter of the core (100-0 cm, 2 = 11.03 ± 8.86% of total weight). Throughout the core there is an inverse relationship between organic and CaCO 3 content, particularly in the top meter. Extrapolation to the bottom of the core using linear regression based on ~4C-dating yields a date of ca. 30,000 years B.P. Results indicate that Lake Ohrid has remained an oligotrophic lake throughout the period represented by Core 9. Diatom analysis shows one persistent group of diatoms throughout the core. This group consists of Cyclotella fottii, C. hustedtii, and C. hustedtii vat.1 and is referred to as the Cyclotella complex. Between 885-650 cm (ca. 30,000-20,000 yr B.P.) there is a sharp increase in numbers and a slight increase in diversity of species. This may correspond with the beginning of the warmer, more humid middle Pleniglacial. Between 650-100 cm (ca. 20,000-10,000 yr B2.) the Cyclotella complex appears usually alone in small numbers. There are a few other scattered species in this section, mainly Opephora martyi and Fragilaria pinnata. This section of the core probably corresponds with the cold upper Pleniglacial of the Wiirm (Weichselian). Between 100-0 cm (ca. 10,000-0 yr B.P.) there is the largest increase in number and diversity of species, particularly above 60 cm. The Cyclotella complex, C. ocellata, Cyclotella sp.1, Stephanodiscus astraea var. intermedia fo.1 and Stephanodiscus sp.1 are dominant. This is the only section of the core in which Stephanodiscus species occur, and probably corresponds with the Holocene.

Pliocene sediments from hydraulic piston cores of Deep Sea Drilling Project sites 572 and 573 in the eastern equatorial Pacific provide material for a high‐resolution stratigraphic and paleoceanographic study during a period of time from 2.4 to 3.7 Ma. Radiolarian stratigraphy of these two sites reveals two major faunal events. The older event involves the gradual disappearance of five species and the appearance of three equatorial surface‐dwelling radiolarian species and occurs at the Gauss/Gilbert paleomagnetic reversal boundary which is coincident with the time of the closing of the Isthmus of Panama around 3.5 Ma [Berggren and Hollister, 1974; Keigwin, 1978, 1982a, b]. The younger event involves a disappearance and appearance of two mainly Subarctic species and occurs at 2.9 Ma, prior to the onset of northern hemisphere glaciation as dated in North Atlantic sections. Analysis of quantitative radiolarian data for extant species divides the Pliocene fauna into two assemblages which are composed of radiolarian species that are abundant in the surface sediments of central and eastern equatorial regions. From the time series variations of these fauna, the variability of these factors has remained constant over the time interval at the eastern site but underwent a stepwise decrease at the western site. Paleotemperature transfer function techniques provided quantitative comparisons between Pliocene and Pleistocene paleooceanographic variability. At the more western site, a shift in paleotemperature estimates occurred. Using the modern day observation that the slope of the thermocline is related to the magnitude of westward wind stress, this change corresponds to an increase in wind stress. This event has been dated at about 2.8 Ma and may represent an important oceanic and atmospheric precursor to the major onset of northern hemisphere glaciation at 2.4 Ma. From the modern relationship between seasonal differences in temperatures at each site the Pliocene gradient in seasonally has been compared with the Pleistocene (and modern) gradients. Relative to the Pleistocene, seasonal differences in temperature were the same for the more eastern site but lower at the western site. The Pliocene gradient in seasonally was thus located farther east toward the South American continent than during the Pleistocene. No influence of the final closure of the Isthmus of Panama is seen in the extant radiolarian data for sites 572 and 573 during the time interval from 2.4 Ma to 3.7 Ma.

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