Data compilation on the biological response to ocean acidification: environmental and experimental context of data sets and related literature

The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.

(Table 1) Helium and Thorium 230 excess concentrations in sediment cores B18 and B25

At four sites in the central equatorial Pacific Ocean the flux of extraterrestrial 3He, determined using the excess 230Th profiling method, is 8 * 10**-13 cm**3 STP/cm**2/ka. This supply rate is constant to within 30%. At these same sites, however, the burial rate of 3He, determined using chronostratigraphic accumulation rates, varies by more than a factor of 3. The lowest burial rates, which occur north of the equator at 1°N, 139°W are lower than the global average rate of supply of extraterrestrial 3He by 20% and indicate that sediment winnowing may have occurred. The highest burial rates, which are recorded at the equator and at 2°S, are higher than the rate of supply of extraterrestrial 3He by 100%, and these provide evidence for sediment focusing. By analyzing several proxies measured in core PC72 sediments spanning the past 450 kyr we demonstrate that periods of maximum burial rates of 230Th, 3He, 10Be, Ti, and barite, with a maximum peak-to-trough amplitude of a factor of 6, take place systematically during glacial time. However, the ratio of any one proxy to another is constant to within 30% over the entire length of the records. Given that each proxy represents a different source (234U decay in seawater, interplanetary dust, upper atmosphere, continental dust, or upper ocean), our preferred interpretation for the covariation is that the climate-related changes in burial rates are driven by changes in sediment focusing.

Grain size analysis of sediment coring site CRP-2 from the Ross Sea, Antarctica

The purpose of this note is to present results of grain size analyses from 118 samples of the CRP-2/2A core using sieve and Sedigraph techniques. The samples were selected to represent the range of facies encountered, and tend to become more widely spaced with depth. Fifteen came from the upper 27 m of Quaternary and Pliocene sediments, 62 from the early Miocene-late Oligocene strata (27 to 307 mbsf), and 41 from the early Oligocene strata beneath (307 to 624 mbsf). The results are intended to provide reference data for lithological descriptions in the core logs (Cape Roberts Science Team, 1999), and to help with facies interpretation. The analytical technique used for determining size frequency of the sand fraction in our samples (sieving) is simple, physical and widely practised for over a century. Thus it provides a useful reference point for analyses produced by other faster and more sophisticated techniques, such as the Malvern laser particle size analysis system (Woolfe et al., 2000), and estimates derived from measurements taken with down-hole logging tools (Bücker, pers. com., 1999).

Nd, Pb, and Be isotopes of ferromanaganese crusts of the Atlantic Ocean

The isotopic composition of Nd in present-day deep waters of the central and northeastern Atlantic Ocean is thought to fingerprint mixing of North Atlantic Deep Water with Antarctic Bottom Water. The central Atlantic Romanche and Vema Fracture Zones are considered the most important pathways for deep water exchange between the western and eastern Atlantic basins today. We present new Nd isotope records of the deepwater evolution in the fracture zones obtained from ferromanganese crusts, which are inconsistent with simple water mass mixing alone prior to 3 Ma and require additional inputs from other sources. The new Pb isotope time series from the fracture zones are inexplicable by simple mixing of North Atlantic Deep Water and Antarctic Bottom Water for the entire past 33 Myr. The distinct and relatively invariable Nd and Pb isotope records of deep waters in the fracture zones appear instead to have been controlled to a large extent by contributions from Saharan dust and the Orinoco/Amazon Rivers. Thus the previously observed similarity of Nd and Pb isotope time series from the western and eastern North Atlantic basins is better explainable by direct supply of Labrador Seawater to the eastern basin via a northern pathway rather than by advection of North Atlantic Deep Water via the Romanche and Vema Fracture Zones.

Nd, Pb, and Be isotopes of ferromanaganese crusts of the South Pacific

The application of radiogenic isotopes to the study of Cenozoic circulation patterns in the South Pacific Ocean has been hampered by the fact that records from only equatorial Pacific deep water have been available. We present new Pb and Nd isotope time series for two ferromanganese crusts that grew from equatorial Pacific bottom water (D137-01, 'Nova', 7219 m water depth) and southwest Pacific deep water (63KD, 'Tasman', 1700 m water depth). The crusts were dated using 10Be/9Be ratios combined with constant Co-flux dating and yield time series for the past 38 and 23 Myr, respectively. The surface Nd and Pb isotope distributions are consistent with the present-day circulation pattern, and therefore the new records are considered suitable to reconstruct Eocene through Miocene paleoceanography for the South Pacific. The isotope time series of crusts Nova and Tasman suggest that equatorial Pacific deep water and waters from the Southern Ocean supplied the dissolved trace metals to both sites over the past 38 Myr. Changes in the isotopic composition of crust Nova are interpreted to reflect development of the Antarctic Circumpolar Current and changes in Pacific deep water circulation caused by the build up of the East Antarctic Ice Sheet. The Nd isotopic composition of the shallower water site in the southwest Pacific appears to have been more sensitive to circulation changes resulting from closure of the Indonesian seaway.