Biology community and bottom sediments in the West Bay of the Furugelm Island, Sea of Japan

An experiment was carried out on the soft bottom in the sublitoral zone of the Furugelm Island (Peter the Great Bay, Sea of Japan) to study formation of benthic communities. Boxes with defauned sediments were placed on depths of 4, 6 and 13 m and exposed during 60 days in the summer period. Half of them were covered with a net with mesh size 2 cm to prevent effect of large predators. It was found that spatial pattern of invertebrates' sinking in the bay conforms to distribution of benthic communities. Larvae of benthic invertebrates sinks in general in places inhabited by their adult species. The main factors responsible for recolonzation are: sediment type and local hydrodynamic conditions. Heart-shaped sea urchin Echinocardium cordatum is numerically dominated in the bay on depth 3-4.5 m, but its larvae sinks in the deeper area. Community structure is supported by mature specimen migration to places inhabited by species. Predators affect largely on the species.

Benthic foraminifers from the Japan Sea

Five holes were drilled at two sites in the Sea of Japan during Ocean Drilling Program (ODP) Leg 128. Site 798 is located on Oki Ridge at a depth of about 900 m. Sediment age at Site 798 ranges from Pliocene to Holocene. Site 799 is located in the Kita-Yamato Trough at depth of 2000 m and below the present calcite compensation depth (CCD); the sediment ranges from Miocene to Holocene in age. Samples from all holes contain benthic foraminifers. Faunal evidence of downslope displacement is frequent in Holes 799A and 799B. The vertical frequency distribution of some dominant species shows that significant faunal changes occur in Holes 798A-C on Oki Ridge. Based on the faunal change and the thickness of sediments, it appears that the Oki Ridge was uplifted more than 1,000 m during last 4 m.y. Benthic foraminifers also demonstrate that the water depth of Site 799 rapidly changed from upper bathyal to lower bathyal during middle Miocene time. The appearance of benthic foraminifer species common to anaerobic environments suggests that the dysaerobic to anaerobic bottom conditions existed during the evolution of the Sea of Japan. Faunal distributions also suggest that the 'Tertiary-type' species recognized in the Neogene strata of the Japan Sea coastal regions disappeared sequentially from the Sea of Japan during Pliocene to late Pleistocene.

Neogene Radiolarians from the Kerguelen Plateau

Abundant, generally well-preserved radiolarians from Sites 737, 744, 745, 746, 747, 748, and 751 were used in stratigraphic analysis of Neogene, and particularly middle Miocene to Holocene, Kerguelen Plateau sediments. The composite Kerguelen section is more complete than the Weddell Sea sections recovered by Leg 113, and the radiolarians are better preserved. Leg 113 radiolarian zonations of Weddell Sea sites were applicable with only slight modification, and three new zones - Siphonosphaera vesuvius, Acrosphaeral labrata, and Amphymenium challengerae - are proposed for the latest Miocene. Geologic age estimates are given for all radiolarian zones used. Major hiatuses affecting most sites were seen within the middle Miocene, in the latest Miocene, and latest Pliocene. Five new species are described: Acrosphaera? labrata, Acrosphaera? mercurius, Siphonosphaera vesuvius, Actinomma? magnifenestra, and Helotholus? haysi.

Calcareous nannofossils in sediments of the Japan Sea

Preliminary results of the biostratigraphic analysis of calcareous nannofossils recovered from Ocean Drilling Program Leg 128, Sites 798 and 799, provide clues to the Quaternary oceanography of the Japan Sea. The distribution of calcareous nannofossils from the Quaternary sediments at Site 798 (903 m water depth) may record the position of an Oceanographic frontal boundary between warm water derived from a branch of the Kuroshio Current as it entered the Japan Sea through the Tsushima Straits to the south, and colder water introduced into the western portion of the Japan Sea derived from the winter chilling of northern Japan Sea surface waters. This Oceanographic front probably oscillated north-south over Site 798 in response to glacial/interglacial cycles, or perhaps to some other climatic event or combination of events unique to the Japan Sea. During the last 1.5 m.y., six major intervals are recognized when the Oceanographic front may have been north of Site 798 separated by five major intervals when the frontal boundary may have been south of the site. These migrations were centered around approximately 0.125, 0.29, 0.56, 0.62, 0.85, 0.91, 0.98, 1.0, 1.11, and 1.5 Ma, which correspond to the boundaries separating nannofossil-rich sediments from barren or nearly barren, low-carbonate intervals. Nannofossil-rich intervals may represent times when the frontal boundary was north of Site 798, and the site was above the CCD. Barren or nearly barren intervals represent times when the frontal boundary may have been south of Site 798 and the CCD was probably higher. The distribution of calcareous nannofossils at Site 799 (2073 m water depth) appears to be controlled more by the depth of the CCD than by any climatic effects. The FOD (first occurrence datum) of Emiliania huxleyi, the LOD (last occurrence datum) of Psuedoemiliania lacunosa, Helicosphaera sellii, Calcidiscus macintyrei (10 ?m), and the FOD and LOD of Reticulofenestra asanoi are recognized from Site 798 cores. The LOD of P. lacunosa is observed in sediments from Site 799. Only in the sediments younger than 1.5 Ma are the nannofossils from Sites 798 and 799 preserved well enough and sufficiently numerous for age dating and paleoceanographic conjecture. In-situ dissolution in older sediments at both sites precludes any dating or paleoenvironmental interpretations.

Pollen profiles from 8 sediment cores from the Degersee, Southern Germany

The discovery of a neolithic pile field in the shallow water near the eastern shore of the Degersee confirmed earlier palynological and sedimentological studies stating that early man was active in the region since more than 6000 years. The already available off-site data were freshly assessed, completed by additional data from old and new cores and the interpretations revised. A common time scale for the off-site data and the on-site data was obtained by AMS dating of terrestrial macro remains of the neolithic section of off-site core De_I+De_H. The ages can thus be parallelled with AMS ages of construction timber on-site. Pollen analyses from all cores provide a further time scale. The continuously and densely sampled pollen profile of the profundal zone embracing the entire Late glacial and Holocene serves as a reference. From the Boreal onwards the relative ages are transformed by AMS ages and varve counts into calibrated and absolute. A transect cored close to the neolithic pile field across the lake marl-platform demonstrates its geological architecture in the shallow water since the Lateglacial. Studies of the microfabric of thin sections of drilled cores and of box cores from the excavations demonstrate that neolithic settlements now at 2-3,5 m water depth had been erected on lake marl freshly fallen dry, thus indicating earlier lake levels dropped by 1.5-2 m. The neolithic section of the highly resolved off-site profile in the lake=s profundal zone has laminated and calcareous zones alternating with massive ones. Assemblages of diatoms and concentrations of trace elements changing simultaneously characterise the calcareous sections as deposits of low lake levels that lasted between some 40 and more than 300 years. The ages of discovered lake shore dwellings fall into calcareous segments with low lake levels. From the end of the Upper Atlantic period (F VII) appear Secondary Forest Cycles in the beech forest, a man-made sequence of repeated vegetational development with an identical pattern: With a decrease of beech pollen appear pollen of grasses, herbs and cultural indicators. These are suppressed by the light demanding hazel and birch, those again by ash, and finally by the shade demanding beech forming a new pollen peak. Seven main Forest Cycles are identified In the upper Neolithic period each comprising some 250, 450 or 800 years. They are subdivided into subcycles that can be broken down by very dense sampling in even shorter cycles of decadal length. Farming settlers have caused minor patchy clearances of the beech-mixed-forest with the use of fire. The phases of clearance coincide with peaks of charcoal and low stands of the lake levels. The Secondary Forest Cycles and the continuous occurrence of charcoal prove a continued occupation of the region. Together with the repeated restoration of the beech climax forest they point to pulsating occupation probably associated with dynamic demography. The synchronism of the many palynological, sedimentological and archaeological data point to an external forcing as the climate that affects comprehensively all these proxies. The fluctuations of the activity of the sun as manifested in the residual d14C go largely along with the proxies. The initial clearances at the begin of the forest cycles are linked to low lake levels and negative values of d14C that point to dry and warm phases of a more continental climate type. The subcycles exist independent from climatic changes, indicating that early man acted largely independent from external forces.

Cenozoic radiolaria in the western North Atlantic

Eight Cenozoic radiolarian zones were recognized in samples from two holes at Site 603, drilled on the lower continental rise off North America during Leg 93 of the Deep Sea Drilling Project. Paleocene to early Eocene radiolarian zones (Bekoma bidartensis, Buryella clinata, and Phormocyrtis striata striata zones) and early to late Miocene radiolarian zones (Calocycletta costata, Dorcadospyris alata, Diartus petterssoni, and Didymocyrtis antepenultima zones) were recognized in sediments from Holes 603 and 603B. In addition, a new Paleocene Bekoma campechensis radiolarian Zone is defined by the interval between the first morphotypic appearance of B. campechensis and the B. campechensis-B. bidartensis evolutionary transition. This zone is immediately below the B. bidartensis Zone of Foreman (1973), and has previously been discussed as a Paleocene "unnamed zone" by other investigators. A hiatus between Neogene and Paleogene sequences was also recognized in the radiolarian faunas.

Pollen records and age determination of site Bokanjacko Blato

In summary, one may conclude that human influence in the Bokanjac area started in the Eneolithic or Earlier Bronze Age - the third to second millennia Cal. BC. Traces of agriculture are weak or missing in the pollen diagram but grazing is indicated. Chestnut and walnut were introduced by humans to the area in classical times. These findings are in general agreement with the results of earlier studies at coastal sites north-west and south-east of Bokanjacko Blato.

Benthic and planktonic foraminifera in the Japan Sea

Biostratigraphy and paleoenvironmental history of deep and surficial waters of the Japan Sea are addressed using sequences recovered from the floor of the backarc basin. The study is divided into two parts: (1) foraminifer biostratigraphy and paleoenvironmental assessment of sedimentary sequences recovered from above igneous basement at the four sites and (2) detailed planktonic foraminifer paleoenvironmental analysis of Quaternary and Pliocene sequences from Sites 794 and 797 in the Yamato Basin. A total of 253 samples were examined for the foraminifer biostratigraphy and 325 samples for the detailed paleoenvironmental study of Quaternary and Pliocene sequences. Low abundance and sporadic occurrence of foraminifers limited interpretation of results. Foraminifer-bearing intervals were correlated where possible to diatom and calcareous nannofossil zonations, and the sequences were successfully assigned to the foraminifer zonation of Matsunaga. Unfortunately, extensive barren intervals and sporadic occurrences of planktonic foraminifers prevented zonation of Quaternary and Pliocene intervals, although some interesting conclusions about paleoenvironment were possible and are listed below. A sequence of Neogene (sensu lato) paleoenvironmental events were identified: (1) deepening of the Yamato basins to middle bathyal depths by the early to middle Miocene, an event contemporaneous with the age of some deep basins known from uplifted sections adjacent to the Japan Basin; (2) cooling of the Japan Sea in the early middle Miocene; (3) oxygenation of deep waters in the late Miocene; (4) further cooling of surficial water masses between the Olduvai Subchron and the Brunhes/Matuyama Boundary; and (5) extermination of lower middle bathyal faunas and replacement by upper middle bathyal faunas near the base of the Quaternary.

Diatom events and Neogene nannofossils of ODP Hole 201-1225A

Shipboard investigation of magnetostratigraphy and shore-based investigation of diatoms and calcareous nannofossils were used to identify datum events in sedimentary successions collected at Ocean Drilling Program (ODP) Leg 201 Site 1225. The goal was to extend the magnetic record previously studied at the same site, ODP Leg 138 Site 851, and provide a comprehensive age model for Site 1225. Two high-magnetic intensity zones at 0-70 and 200-255 meters below seafloor (mbsf) were correlated with lithologic Subunits IA and IC in Hole 1225A. Subunit IA (0-70 mbsf) contains the magnetic reversal record until the Cochiti Subchronozone (3.8 Ma) and has a sedimentation rate of 1.7 cm/k.y. This agrees with previous work done at Site 851. Subunit IC (200-255 mbsf) was not sampled at Site 851. Diatom and nannofossil biostratigraphy constrained this subunit, and we found it to contain the magnetic reversal record between Subchrons C4n.2r and C5n.2n (8.6-9.7 Ma), yielding a sedimentation rate of 2.7 cm/k.y. Biostratigraphy was used to establish the sedimentation rates within Subunits IB and ID (70-200 mbsf and 255-300 mbsf, respectively). These subunits had higher sedimentation rates (~3.4 cm/k.y.) and coincide with the late Miocene-early Pliocene biogenic bloom event (4.5-7 Ma) and the Miocene global cooling trend (10-15 Ma). High biogenic productivity associated with these subunits resulted in the pyritization of the magnetic signal. In lithologic Subunit ID, basement flow is another factor that may be altering the magnetic signal; however, the good correlation between the biostratigraphy and magnetostratigraphy indicates that the magnetic record was locked-in near the seafloor and suggests the age model is robust.

Pollen record from Kleiner Mochowsee, Germany

A Holocene pollen diagram from Kleiner Mochowsee (northern Niederlausitz, East Germany) shows pine as an important constituent of the woodland south of the Schwielochsee. Oak woodland was widespread since the Atlantic. Betula lost its importance at the end of the Preboreal. Fagus is represented continuously in the pollen record since the Atlantic, Carpinus since the Subboreal. However, the two latter tree species remain without great importance throughout the whole pollen record. The poor sandy soils are furthermore reflected by the low values of Corylus during the Boreal, comparable to other records from Berlin and its surrounding area. The 'classical' elm decline could be shown for the Niederlausitz, radiocarbon dates assume a contemporaneous age for this event with other records from northern Germany. Only small-scaled human impact is indicated in prehistoric times, during the migration period it seems to have ceased completely. Later, in the Medieval, deforestation and tillage can be shown. Secale was cultivated since the early Medieval; an accompanying weed flora appeared at the same time. Cultivation of Fagopyrum and Linum usitatissimum could be shown for the late Medieval times.

Pollen analysis from Fiekers Busch, Rinteln, Germany

Fiekers Busch is a wet alder wood close to Rinteln (southwest of Hannover/West Germany) existing there since about 6 000 or - at the most - 7 500 radiocarbon years. The sandy layers below the peaty sequence date from about 9 000 BP. The pollen diagram shows the basic trends of the postglacial vegetational development. Low pollen frequency and poor pollen preservation do , however, strongly restrict the possibilities to explain the peculiarities of the pollendiagram, especially the high pine and linden values.