Presence of competitors influences photosynthesis, but not growth, of the hard coral Porites cylindrica at elevated seawater CO2

Changes in environmental conditions, such as those caused by elevated carbon dioxide (CO2), potentially alter the outcome of competitive interactions between species. This study aimed to understand how elevated CO2 could influence competitive interactions between hard and soft corals, by investigating growth and photosynthetic activity of Porites cylindrica (a hard coral) under elevated CO2 and in the presence of another hard coral and two soft coral competitors. Corals were collected from reefs around Orpheus and Pelorus Islands on the Great Barrier Reef, Australia. They were then exposed to elevated pCO2 for 4 weeks with two CO2 treatments: intermediate (pCO2 648) and high (pCO2 1003) compared with a control (unmanipulated seawater) treatment (pCO2 358). Porites cylindrica growth did not vary among pCO2 treatments, regardless of the presence and type of competitors, nor was the growth of another hard coral species, Acropora cerealis, affected by pCO2 treatment. Photosynthetic rates of P. cylindrica were sensitive to variations in pCO2, and varied between the side of the fragment facing the competitors vs. the side facing away from the competitor. However, variation in photosynthetic rates depended on pCO2 treatment, competitor identity, and whether the photosynthetic yields were measured as maximum or effective photosynthetic yield. This study suggests that elevated CO2 may impair photosynthetic activity, but not growth, of a hard coral under competition and confirms the hypothesis that soft corals are generally resistant to elevated CO2. Overall, our results indicate that shifts in the species composition in coral communities as a result of elevated CO2 could be more strongly related to the individual tolerance of different species rather than a result of competitive interactions between species.

Diversity and faunal composition of benthic foraminifera in Hole 44-390A on the Blake Nose Plateau

Benthic foraminiferal assemblages are a widespread tool to understand changes in organic matter flux and bottom-water oxygenation and their relation to paleoceanographic changes in the Upper Cretaceous oceans. In this study, assemblage data (diversity, total number, and number per species and gram) from Deep Sea Drilling Project (DSDP) Site 390 (Blake Nose, western North Atlantic) were processed for the lower Maastrichtian (Globotruncana falsostuarti - Gansserina gansseri Planktic Foraminiferal Zone). These data document significant changes in nutrient flux to the sea floor as well as bottom-water oxygenation during this time interval. Parallel to the observed changes in the benthic foraminiferal assemblages the number of inoceramid shells decreases, reflecting also a significant increase in bottom-water oxygenation. We speculate, that these data could reflect the onset of a shift from warmer low-latitude to cooler high-latitude deep-water sources. This speculation will predate the major reorganization of the oceanic circulation resulting in a circulation mode similar to today at the Early/Late Maastrichtian boundary by ~1 Ma and therefore improves our understanding of Late Cretaceous paleoceanography.

Abundance and biomass of zooplankton from 1986-1994 collected in front of Constanta city, Black Sea

The Est Constanta 1986-1994 dataset contains zooplankton data collected allong a 5 station transect in front of the city Constanta (44°10'N, 28°41.5'E - EC1; 44°10'N, 28°47'E - EC2; 44°10'N, 28°54'E - EC3; 44°10'N, 29°08'E - EC4; 44°10'N, 29°22'E - EC5). Zooplankton sampling was undertaken at 5 stations where samples were collected using a Juday closing net in the 0-10, 10-25, 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

Abundance and biomass of mesozooplankton from the Romanian littoral during DANUBS_2002 in spring and autumn 2002

The Danubs 2002 dataset contains zooplankton data collected in April, June,September and October 2002 in 11 station allong 5 transect in front of the Romanian littoral. Zooplankton sampling was undertaken at 11 stations where samples were collected using a Juday closing net in the 0-10, 10-25, and 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

Living benthic foraminifera of the western and southern Arabian Sea

Sediments from the western and southern part of the Arabian Sea were collected periodically in the spring intermonsoon between March and May 1997 and additionally at the end of the Northeast Monsoon in February 1998. Assemblages of Rose Bengal stained, living deep-sea benthic foraminifera, their densities, vertical distribution pattern, and diversity were analysed after the Northeast Monsoon and short-time changes were recorded. In the western Arabian Sea, foraminiferal numbers increased steadily between March and the beginning of May, especially in the smaller size classes (30-63 µm, 63-125 µm). At the same time, the deepening of the foraminiferal living horizon, variable diversity and rapid variations between dominant foraminiferal communities were observed. We interpret these observations as the time-dependent response of benthic foraminifera to enhanced organic carbon fluxes during and after the Northeast Monsoon. In the southern Arabian Sea, constant low foraminiferal abundances during time, no distinctive change in the vertical distribution, reduced diversity, and more stable foraminiferal communities were noticed, which indicates no or little influence of the Northeast Monsoon to benthic foraminifera in this region.

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.

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.

Benthic foraminifera in surface sediments of the Arabian Sea

Assemblages of living deep-sea benthic foraminifera, their densities, vertical distribution pattern, and diversity, were investigated in the intermonsoon period after the northeast monsoon in the Arabian Sea in spring 1997. Foraminiferal numbers show a distinct gradient from north to south, with a maximum of 623 foraminifera in 50 cm**3 at the northern site. High percentages of small foraminifera were found in the western and northern part of the Arabian Sea. Most stations show a typical vertical distribution with a maximum in the first centimeter and decreasing numbers with increasing sediment depths. But at the central station, high densities can be found even in deeper sediment layers. Diversity is very high at the northern and western sites, but reduced at the central and southern stations. Data and faunal assemblages were compared with studies carried out in 1995. A principal component analysis of intermonsoon assemblages shows that the living benthic foraminifera can be characterized by five principal component communities. Dominant communities influencing each site differ strongly between the two years. In spring 1997, stations in the north, west and central Arabian Sea were dominated by opportunistic species, indicating the influence of fresh sedimentation pulses or enhanced organic carbon fluxes after the northeast monsoon.

Mid-Pliocene diatom and palynological assemblages north-northeast of Cape Adare, Antarctica

Microfossil assemblages in Pliocene sediments from DSDP Site 274 (68°59.81'S, 173°2564'E) provide data on the age of the sediments and suggest the presence of Nothofagus (southern beach) in Antarctica during the Pliocene. A suite of 17 samples was collected in an interval from Samples 28-274-6R-1, 83-87 cm to 28-274-11R-4, 73-77 cm (48.33-100.29 mbsf). Biostratigraphic study of the abundant diatom assemblages combined with published radiolarian data indicates that the sample interval ranges in age from 5.0 to 2.2 Ma, with an apparent unconformity between about 3.8 and 3.2 Ma. Nothofagidites (the genus for fossil pollen referable to Nothofagus) occurs throughout the interval, as well as pollen and spores with known stratigraphic ranges that unequivocally indicate reworking from older rocks. Species of Nothofagidites recovered include N. asperus, N. brachyspinulosus, N. flemingii, N. senectus, and N. sp. cf. N. lachlaniae; the latter form is previously known from the Sirius Group in the Transantarctic Mountains. Abundant palynomorphs were recovered in only three of the samples from Site 274 (Samples 28-274-9R-2,15-19 cm; 28-274-9R-2,48-52 cm; and 28-274-9R-2,65-69 cm). Based on the diatom and radiolarian biostratigraphic data, the ages of these samples range from 3.00 to 3.01 Ma. The relative abundance of N. sp. cf. N. lachlaniae in the three samples is an order of magnitude higher than relative abundances for the other species of Nothofagidites in the same samples. The signiticantly higher relative abundance of N. sp. cf. N. luchlaniae suggests that this pollen was derived from trees of Nothofugus that were living in Antarctica during the mid Pliocene. Diatom assemblages from these three samples indicate that sediments in this interval were rapidly deposited as biogenic oozes in an open-ocean setting relatively free of sea ice, thus decreasing the possibility of reworking from a single source bed rich in N. sp. cf. N. lachlaniae. Clearly, more detailed work in additional well-dated cores from around Antarctica is needed before a clear picture of the Neogene history of Antarctic terrestrial vegetation emerges.

Abundance and biomass of zooplankton from 1981-1985 collected in front of Constanta city, Black Sea

The Est Constanta 1981-1985 dataset contains zooplankton data collected allong a 5 station transect in front of the city Constanta (44°10'N, 28°41.5'E - EC1; 44°10'N, 28°47'E - EC2; 44°10'N, 28°54'E - EC3; 44°10'N, 29°08'E - EC4; 44°10'N, 29°22'E - EC5). Zooplankton sampling was undertaken at 5 stations where samples were collected using a Juday closing net in the 0-10, 10-25, 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

Abundance and biomass of zooplankton from the Romanian littoral collected in April, May and June 1997

The SHELF 1997 dataset contains zooplankton data collected in April, May and June 1997 5 transect in front of the Romanian littoral . Zooplankton sampling was undertaken using a Juday closing net in the 0-10, 10-25, and 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.