Mean cover and frequencies of vascular plant species during three decades around Abisko Scientific Research Station

Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, sub-Arctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977-1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.

Epiphytic orchid diversity and community composition in managed and natural moist evergreen Afromontane forest in SW Ethiopia

In SW Ethiopia, the moist evergreen Afromontane forest has become extremely fragmented and most of the remnants are intensively managed for coffee cultivation (Coffea arabica), with considerable impacts on biodiversity and ecosystem functioning. Because epiphytic orchids are potential indicators for forest quality and a proxy for overall forest biodiversity, we assessed the effect of forest management and forest fragmentation on epiphytic orchid diversity. We selected managed forest sites from both large and small forest remnants and compared their epiphytic orchid diversity with the diversity of natural unfragmented forest. We surveyed 339 canopy trees using rope climbing techniques. Orchid richness decreased and community composition changed, from the natural unfragmented forest, over the large managed forest fragments to the small managed forest fragments. This indicates that both forest management and fragmentation contribute to the loss of epiphytic orchids. Both the removal of large canopy trees typical for coffee management, and the occurrence of edge effects accompanying forest fragmentation are likely responsible for species loss and community composition changes. Even though some endangered orchid species persist even in the smallest fragments, large managed forest fragments are better options for the conservation of epiphytic orchids than small managed forests. Our results ultimately show that even though shade coffee cultivation is considered as a close-to-nature practice and is promoted as biodiversity conservation friendly, it cannot compete with the epiphytic orchid conservation benefit generated by unmanaged moist evergreen Afromontane forests.

Pollen abundance in ODP Site 123-765 (Table 1)

Middle Miocene to Holocene pollen assemblages reveal a history of environmental change in northern Australia. Grass pollen appeared, but was rare, in the late Miocene and was consistently present throughout the Pliocene, but did not become abundant until the Pleistocene. Myrtaceae pollen, characteristic of late Cenozoic assemblages in eastern Australia, is poorly represented, and no unequivocal evidence of rain forest was found.

Granulometry, biogenic silica content, magnetic susceptibility and bulk densities of ODP Site 188-1165

The Prydz Bay area is a key region for studying and understanding the history of the eastern Antarctic Continental Ice Sheet (O'Brien, Cooper, Richter, et al., 2001, doi:10.2973/odp.proc.ir.188.2001). Ocean Drilling Program (ODP) Site 1165 is situated in a water depth of 3357 m on the continental rise offshore from Prydz Bay and lies in front of the outlet for the Lambert Glacier-Amery Ice Shelf system that today drains 22% of East Antarctica. The site was drilled into mixed pelagic and hemipelagic sediments from the southwestern side of the Wild Drift. The drift is an elongate sediment body formed by the interaction of sediment supplied from continental shelf and slope with westward-flowing bottom currents. The sedimentary sequence is characterized by alternations between a generally gray to dark gray facies and a green to greenish gray facies. The greenish facies are structureless diatom-bearing clays with common bioturbation and larger amounts (>15%-20%) of biogenic silica, dispersed clasts, and lonestones than the dark gray facies, which are mostly less bioturbated clay with some silt laminations (Shipboard Scientific Party, 2001, doi:10.2973/odp.proc.ir.188.103.2001). High-quality advanced piston corer and extended core barrel cores containing nearly complete sections of middle Miocene to early Pliocene age allow a detailed characterization of sedimentary cycles and can provide indications for ice advances of the Lambert Glacier system into Prydz Bay, for the extent of sea ice, and for changes in oceanic circulation. The purpose of this work is to provide a data set of coarse-fraction mass percentage (>63, >125, and >250 µm) and biogenic silica content measured on sediments of late Miocene to early Pliocene age drilled at Site 1165. Additionally, high-resolution records of magnetic susceptibility (MS) and gamma ray attenuation (GRA) bulk density are presented. These shipboard data sets were edited postcruise. Furthermore, I provide a high-resolution dry bulk density record that is derived from GRA bulk density and can be used for the calculation of mass accumulation rates. These sedimentological and physical parameters will be used in future work to understand the depositional pattern of alternating biogenic and terrigenous sediments that was observed at Site 1165 (Shipboard Scientific Party, 2001, doi:10.2973/odp.proc.ir.188.103.2001).

Paleointensity record of Site 320-U1336

We present a high-resolution magnetostratigraphy and relative paleointensity (RPI) record derived from the upper 85 meters of IODP Site U1336, an equatorial Pacific early to middle Miocene succession recovered during Expedition 320/321. The magnetostratigraphy is well resolved with reversals typically located to within a few centimeters resulting in a well-constrained age model. The lowest normal polarity interval, from 85 to 74.87 meters, is interpreted as the upper part of Chron C6n (18.614-19.599 Ma). Another 33 magnetozones occur from 74.87 to 0.85 m, which are interpret to represent the continuous sequence of chrons from Chron C5Er (18.431-18.614 Ma) up to the top of Chron C5An.1n (12.014 Ma). We identify three new possible subchrons within Chron C5Cn.1n, Chron 5Bn.1r, and C5ABn. Sedimentation rates vary from about 7 to 15 m/Myr with a mean of about 10 m/Myr. We observe rapid, apparent changes in the sedimentation rate at geomagnetic reversals between ~16 and 19 Ma that indicate a calibration error in geomagnetic polarity timescale (ATNTS2004). The remanence is carried mainly by non-interacting particles of fine-grained magnetite, which have FORC distributions characteristic of biogenic magnetite. Given the relative homogeneity of the remanence carriers throughout the 85-m-thick succession and the quality with which the remanence is recorded, we have constructed a relative paleointensity (RPI) record that provides new insights into middle Miocene geomagnetic field behavior. The RPI record indicates a gradual decline in field strength between 18.5 Ma and 14.5 Ma, and indicates no discernible link between RPI and either chron duration or polarity state.

Mineralogical composition, copper and d18O at DSDP Site 59-448

Alteration in a submarine remnant volcanic arc should leave an important record of (1) the mineralogy of sea water-volcanic arc rock interaction; (2) the chemistry of solid reaction products; (3) the isotopic characteristics of such reactions (Muehlenbachs and Clayton, 1972; Spooner, Beckinsale, et al , 1977; Spooner, Chapman, et al., 1977); (4) the metallogenesis within such a sequence (Mitchell and Bell, 1973); and (5) the geothermal gradient during the alteration. The volcaniclastic breccias, tuffs, and igneous units of Sites 448 (993 m) and 451 (930.5 m) on the Palau-Kyushu and West Mariana ridges, respectively, are particularly suited for such studies because the thick sequences have remained submarine throughout their history, seemingly unaffected by magmatic or hydrothermal events after cessation of volcanic activity. Also, shipboard observations indicated a change in alteration products with depth. At both sites the igneous units and volcaniclastic rocks were altered to brownish clays and zeolites near the top of the volcanic sequence; to bright blue green clays and zeolites at moderate depths; and to very dark, nearly opaque, forest green clays and zeolites at still greater depths. Native copper occurs both as disseminated pockets in the volcaniclastic breccias and vesicular basalts and as veins in the breccias; native copper is restricted to stratigraphic levels characterized by the absence of sulfides or oxides of copper and iron. Although some native copper is found in vesicles of basalts and may be orthomagmatic, most of it is clearly secondary. Near dikes and sills, higher sulfur fugacity conditions caused the precipitation of iron and copper sulfides with an absence of native copper (Garrels and Christ, 1965). The occurrence of native copper may be an initial stage of Cu metallogenesis that forms porphyry coppers in island arcs (Mitchell and Bell, 1973). This study will address primarily the possibility that hydrothermal sea water interaction with volcanic arc rocks has created the mineralogical and isotopic zonation in Leg 59 cores. Hydrothermal activity can be expected in a rapidly growing island arc and is probably the result of a high geothermal gradient prevalent during arc magmatic activity. The chemical character of the alteration is further discussed by Hajash (1981).

Foraminifer datums, opal content and opal accumulation rate of ODP Site 184-1143 sediments

Since the 1970s, Ocean Drilling Program (ODP) and Deep Sea Drilling Program (DSDP) studies have documented high accumulations of biogenic silica and carbonate in the late Miocene-early Pliocene Indian-Pacific Ocean. This high biogenic productivity event, or the "Biogenic Bloom Event," has been dated from 9.0 to 3.5 Ma (Leinen, 1979, doi:10.1130/0016-7606(1979)90<801:BSAITC>2.0.CO;2; Theyer et al., 1985, doi:10.2973/dsdp.proc.85.133.1985; Farrell et al., 1995, doi:10.2973/odp.proc.sr.138.143.1995; Dickens and Owen, 1996, doi:10.1016/0377-8398(95)00054-2, 1999, doi:10.1016/S0025-3227(99)00057-2; Dickens and Barron, 1997, doi:10.1016/S0377-8398(97)00003-0; Berger et al., 1993, doi:10.2973/odp.proc.sr.130.051.1993). It is unknown, however, whether the Biogenic Bloom Event existed in the South China Sea (SCS). High-quality Cenozoic sediment cores taken from the SCS during ODP Leg 184 provide an opportunity to investigate this question. The purpose of this study is to trace and illustrate the change in biogenic productivity in the southern SCS since the late Miocene and the Biogenic Bloom Event in terms of the content and accumulation rate of opal and carbonate at Site 1143.

High-resolution sedimentological and paleontological record of ODP Site 167-1019

Holocene and latest Pleistocene oceanographic conditions and the coastal climate of northern California have varied greatly, based upon high-resolution studies (ca. every 100 years) of diatoms, alkenones, pollen, CaCO3%, and total organic carbon at Ocean Drilling Program (ODP) Site 1019 (41.682°N, 124.930°W, 980 m water depth). Marine climate proxies (alkenone sea surface temperatures [SSTs] and CaCO3%) behaved remarkably like the Greenland Ice Sheet Project (GISP)-2 oxygen isotope record during the Bølling-Allerod, Younger Dryas (YD), and early part of the Holocene. During the YD, alkenone SSTs decreased by >3°C below mean Bølling-Allerod and Holocene SSTs. The early Holocene (ca. 11.6 to 8.2 ka) was a time of generally warm conditions and moderate CaCO3 content (generally >4%). The middle part of the Holocene (ca. 8.2 to 3.2 ka) was marked by alkenone SSTs that were consistently 1-2°C cooler than either the earlier or later parts of the Holocene, by greatly reduced numbers of the gyre-diatom Pseudoeunotia doliolus (<10%), and by a permanent drop in CaCO3% to <3%. Starting at ca. 5.2 ka, coastal redwood and alder began a steady rise, arguing for increasing effective moisture and the development of the north coast temperate rain forest. At ca. 3.2 ka, a permanent ca. 1°C increase in alkenone SST and a threefold increase in P. doliolus signaled a warming of fall and winter SSTs. Intensified (higher amplitude and more frequent) cycles of pine pollen alternating with increased alder and redwood pollen are evidence that rapid changes in effective moisture and seasonal temperature (enhanced El Niño-Southern Oscillation [ENSO] cycles) have characterized the Site 1019 record since about 3.5 ka.

Occurrence of mammalia relicts at site Nörre-Lyngby

Investigations at a Late Weichselian freshwater basin in northwestern Jutland, Denmark, yielded a fairly rich assemblage of vertebrate remains, mostly bones and teeth of small mammals. The remains are primarily allochthonous and the bones have been subjected to different taphonomic pathways and agents. AMS 14C-dates on terrestrial organic remains provided ages of Middle to Late Allerød time. Identifications revealed the first fossil record in Scandinavia of Rana arvalis, Sorex minutus, Ochotona cf. pusilla, Microtus gregalis, Microtus oeconomus, and Sicista cf. betulinu. Spermophilus cf. major and Desmana moschata, previously found only once and twice respectively, were retrieved, and Sorex araneus and Arvicola terrestris were recovered for the first time beyond the Atlantic chronozone. Ecologically, the Nørre Lyngby small mammal fauna can be characterized by its very high and almost equal proportions of boreal forest and steppe elements followed by a relatively high proportion of tundra elements. The fossil species share a modern area of sympatry north of the Caspian Sea from the river Volga in the west to the southern and western slopes of the Urals. If, however, the large Allerød mammals are added, the fauna is without modern analogues. The Nørre Lyngby fauna can be seen as a last expansion of the North European glacial fauna. Provided that an absolute chronology and a differentiated sea-level curve for the area can be established, the Nørre Lyngby fauna could become important for studies in mammalian dispersal and migration rates.

Rarefied allelic richness of the ground beetle Abax parallelepipedus in Germany

Although genetic diversity is one of the key components of biodiversity, its drivers are still not fully understood. While it is known that genetic diversity is affected both by environmental parameters as well as habitat history, these factors are not often tested together. Therefore, we analyzed 14 microsatellite loci in Abax parallelepipedus, a flightless, forest dwelling ground beetle, from 88 plots in two study regions in Germany. We modeled the effects of historical and environmental variables on allelic richness, and found for one of the regions, the Schorfheide-Chorin, a significant effect of the depth of the litter layer, which is a main component of habitat quality, and of the sampling effort, which serves as an inverse proxy for local population size. For the other region, the Schwäbische Alb, none of the potential drivers showed a significant effect on allelic richness. We conclude that the genetic diversity in our study species is being driven by current local population sizes via environmental variables and not by historical processes in the studied regions. This is also supported by lack of genetic differentiation between local populations sampled from ancient and from recent woodlands. We suggest that the potential effects of former fragmentation and recolonization processes have been mitigated by the large and stable local populations of Abax parallelepipedus in combination with the proximity of the ancient and recent woodlands in the studied landscapes.

Geochemistry of ODP Site 202-1233 and river sediments

Bulk sediment chemistry from three Chilean continental margin Ocean Drilling Program sites constrains regional continental erosion over the past 30,000 years. Sediments from thirteen rivers that drain the (mostly igneous) Andes and the (mostly metamorphic) Coast Range, along with existing rock chemistry datasets, define terrestrial provenance for the continental margin sediments. Andean river sediments have high Mg/Al relative to Coast-Range river sediments. Near 36°S, marine sediments have high-Mg/Al (i.e. more Andean) sources during the last glacial period, and lower-Mg/Al (less Andean) sources during the Holocene. Near 41°S a Ti-rich source, likely from coast-range igneous intrusions, is prevalent during Holocene time, whereas high-Mg/Al Andean sources are more prevalent during the last glacial period. We infer that there is a dominant ice-sheet control of sediment sources. At 36°S, Andean-sourced sediment decreased as Andean mountain glaciers retreated after ~17.6 ka, coincident with local oceanic warming and southward retreat of the Patagonian Forest and, by inference, westerly winds. At 41°S Andean sediment dominance peaks and then rapidly declines at ~19 ka, coincident with local oceanic warming and the earliest deglacial sea-level rise. We hypothesize that this decreased flux of Andean material in the south is related to rapid retreat of the marine-based portion of the Patagonian Ice Sheet in response to global sea-level rise, as the resulting flooding of the southern portion of the Central Valley created a sink for Andean sediments in this region. Reversal of the decreasing deglacial Mg/Al trend at 41°S from 14.5 to 13.0 ka is consistent with a brief re-advance of the Patagonian ice sheet coincident with the Antarctic Cold Reversal.

Benthic and fish community composition as well as water quality along the Thousand Islands north of the megacity Jakarta, Indonesia

Worldwide, coral reefs are challenged by multiple stressors due to growing urbanization, industrialization and coastal development. Coral reefs along the Thousand Islands off Jakarta, one of the largest megacities worldwide, have degraded dramatically over recent decades. The shift and decline in coral cover and composition has been extensively studied with a focus on large-scale gradients (i.e. regional drivers), however special focus on local drivers in shaping spatial community composition is still lacking. Here, the spatial impact of anthropogenic stressors on local and regional scales on coral reefs north of Jakarta was investigated. Results indicate that the direct impact of Jakarta is mainly restricted to inshore reefs, separating reefs in Jakarta Bay from reefs along the Thousand Islands further north. A spatial patchwork of differentially degraded reefs is present along the islands as a result of localized anthropogenic effects rather than regional gradients. Pollution is the main anthropogenic stressor, with over 80 % of variation in benthic community composition driven by sedimentation rate, NO2, PO4 and Chlorophyll a. Thus, the spatial structure of reefs is directly related to intense anthropogenic pressure from local as well as regional sources. Therefore, improved spatial management that accounts for both local and regional stressors is needed for effective marine conservation.

(Table 1) Magnetozone boundaries at DSDP Site 68-503

The paleomagnetic measurement procedure at Site 503 was similar to that described for Site 502 (See preceding chapter). Each core section was measured with the longcore spinner magnetometer at 10-cm intervals. In addition, one or more discrete samples were taken from each core section for measurement of the total magnetic vector and its stability against progressive AF demagnetization. There were noteworthy differences in conditions at Site 503, however, that affected the quality and interpretation of the magnetic data and require comment. The most serious problem we encountered was the presence of rust scale from the drill string. Although the dark flecks typically were concentrated near the top of every recovered sediment core, they also smeared down a meter or more between the core liner and sediment, even when the sediment showed no indication of drilling disturbance. Individual rust scales proved to be highly magnetic - presumably because they incorporate small pieces of unoxidized metal. The anomalously high remanent intensities, several orders of magnitude above the uncontaminated sediment values, and scattered remanent directions observed in long-core magnetic measurements on many cores from Site 503 could be attributed to the presence of rust scale.

Stress tests of ODP Site 131-808 sediments

Sediments undergoing accretion in trench-forearc systems are subjected to conditions of large lateral thrusting. This stress regime controls the mechanism of faulting as well as the yield and strength properties of the sediment. Understanding them is therefore crucial for the construction of quantitative models of sediment dynamics in convergent margin settings. For this purpose triaxial and oedometer tests were performed on six whole-round core samples recovered from Site 808 from depths between 173 and 705 mbsf. Samples from five depth intervals were subjected to a triaxial test program that was primarily designed to define yield and strength behavior. Test specimens were cut parallel and normal to the core axis. Additional five oedometer tests with similarly prepared specimens were performed on samples from four depth intervals to evaluate the directional state and degree of sediment compaction. Test results show that the degree of sediment compaction is higher than expected from overburden. This overcompaction increases with depth. A well-developed mechanical anisotropy is evident in all samples tested, regardless of their depth and lithology. Values of yield limit, stiffness, and shear strength are up to 40% higher in the horizontal direction compared to the vertical direction. In addition the test data demonstrate that the axis of the volumetric yield loci have rotated into extensional stress field. This verifies that the mechanical state of sediment in the accretionary wedge is controlled by in-situ stress conditions of extensional nature. The coefficients of lateral stress inferred suggest that the extensional stress regime becomes increasingly effective with depth.