Seawater carbonate chemistry, nutrients, particulate carbon and growth rate of Emiliania huxleyi (AC472), Calcidiscus leptoporus (AC370) and Syracosphaera pulchra (AC418) during experiments, 2011

The response of Emiliania huxleyi (Lohmann) W. W. Hay et H. Mohler, Calcidiscus leptoporus (G. Murray et V. H. Blackman) J. Schiller, andSyracosphaera pulchra Lohmann to elevated partial pressure of carbon dioxide (pCO2) was investigated in batch cultures. We reported on the response of both haploid and diploid life stages of these three species. Growth rate, cell size, particulate inorganic carbon (PIC), and particulate organic carbon (POC) of both life stages were measured at two different pCO2 (400 and 760 parts per million [ppm]), and their organic and inorganic carbon production were calculated. The two life stages within the same species generally exhibited a similar response to elevated pCO2, the response of the haploid stage being often more pronounced than that of the diploid stage. The growth rate was consistently higher at elevated pCO2, but the response of other processes varied among species. Calcification rate of C. leptoporusand of S. pulchra did not change at elevated pCO2, whereas it increased in E. huxleyi. POC production and cell size of both life stages of S. pulchra and of the haploid stage of E. huxleyi markedly decreased at elevated pCO2. It remained unaltered in the diploid stage of E. huxleyi and C. leptoporus and increased in the haploid stage of the latter. The PIC:POC ratio increased in E. huxleyi and was constant in C. leptoporus and S. pulchra. Elevated pCO2 has a significant effect on these three coccolithophore species, the haploid stage being more sensitive. This effect must be taken into account when predicting the fate of coccolithophores in the future ocean.

Planktological-chemical observation during the International Indian Ocean Expedition (IIOE) with RV "Meteor" in 1964/65

The present volume contains the planktological data collected during the expedition of the "Meteor" to the Indian Ocean in 1964/65. It was the main objective of the expedition to study the up- and downwelling conditioned along the western and eastern coasts of the Arabian Sea by the northeastern monsoon. It is from these areas that the greater part of the data here presented was obtained. A few values from the Red Sea have been added. As the title "Planktological-Chemical Data" implies, it was chiefly with the help of chemical methods that the planktological investigations, with the exception of the particle size analysis and phytoplankton counting conducted optically, were carried out. These investigations were above all devoted to a quantitative survey of particulate matter and plankton, the latter being sampled by water-bottle and net. The zooplankton hauls were taken with the Indian Ocean Standard Net according to the international guidelines laid down for the expedition. As a rule, double catches were made at every station, one sample being intended for laboratory analysis at the Indian Ocean Biological Centre in Ernakulam, South India, and the other for the Institut für Meereskunde in Kiel. In addition to determining the standing stock, the production rate of phytoplankton was measured by the 14C method. These experiments were mainly conducted during the latter half of the expedition. The planktological studies primarily covered the euphotic zone, extending into the underlying water layers up to a depth of 600 m. The investigations were above all directed towards ascertaining the quantity of organic substance, formed by primary production, in its relation to environmental conditions and determining whether or not organic substance is actively transported from the surface into the deeper layers by the periodically migration organisms of the deep scattering layers. Depending on the station time available, a few samples could now and then be taken from deeper layers. The present volume of planktological-chemical data addresses itself to all those concerned processing the extensive material collected during the International Indian Ocean Expedition. As a readily accessible work of reference, it hopes to serve as an aid in the evaluation and interpretation of the expedition results. The complementary ecological data such as temperature, salinity, and oxygen content as well as the figures obtained on abundance and distribution in depth of the nutrients essential for primary production may be found in the volume of physical-chemical data published in Series A of the "Meteor"-Forschungsergebnisse No. 2, 1966 (Dietrich et al., 1966).

Properties of seawater and particulate matter (fluorescence) from a WETLabs Eco-FL sensor mounted on the continuous surface water sampling system during the Tara Oceans expedition 2009-2013

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. The present data set provides continuous measurements made with a WETLabs Eco-FL sensor mounted on the flowthrough system between June 4th, 2011 and March 30th, 2012. Data was recorded approximately every 10s. Two issues affected the data: 1. Periods when the water 0.2µm filtered water were used as blanks and 2. Periods where fluorescence was affected by non-photochemical quenching (NPQ, chlorophyll fluorescence is reduced when cells are exposed to light, e.g. Falkowski and Raven, 1997). Median data and their standard deviation were binned to 5min bins with period of light/dark indicated by an added variable (so that NPQ affected data could be neglected if the user so chooses). Data was first calibrated using HPLC data collected on the Tara (there were 36 data within 30min of each other). Fewer were available when there was no evident NPQ and the resulting scale factor was 0.0106 mg Chl m-3/count. To increase the calibration match-ups we used the AC-S data which provided a robust estimate of Chlorophyll (e.g. Boss et al., 2013). Scale factor computed over a much larger range of values than HPLC was 0.0088 mg Chl m-3/count (compared to 0.0079 mg Chl m-3/count based on manufacturer). In the archived data the fluorometer data is merged with the TSG, raw data is provided as well as manufacturer calibration constants, blank computed from filtered measurements and chlorophyll calibrated using the AC-S. For a full description of the processing of the Eco-FL please see Taillandier, 2015.

Seawater carbonate chemistry, nutrients, chlorophyll and diatom Proboscia alata during experiments, 2012

The combined effects of different light and aqueous CO2 conditions were assessed for the Southern Ocean diatom Proboscia alata(Brightwell) Sundström in laboratory experiments. Selected culture conditions (light and CO2(aq)) were representative for the natural ranges in the modern Southern Ocean. Light conditions were 40 (low) and 240 (high) µmol photons/m**2/s. The three CO2(aq) conditions ranged from 8 to 34 µmol/kg CO2(aq) (equivalent to a pCO2 from 137 to 598 µatm, respectively). Clear morphological changes were induced by these different CO2(aq) conditions. Cells in low [CO2(aq)] formed spirals, while many cells in high [CO2(aq)] disintegrated. Cell size and volume were significantly affected by the different CO2(aq) concentrations. Increasing CO2(aq) concentrations led to an increase in particulate organic carbon concentrations per cell in the high light cultures, with exactly the opposite happening in the low light cultures. However, other parameters measured were not influenced by the range of CO2(aq) treatments. This included growth rates, chlorophyll aconcentration and photosynthetic yield (FV/FM). Different light treatments had a large effect on nutrient uptake. High light conditions caused an increased nutrient uptake rate compared to cells grown in low light conditions. Light and CO2 conditions co-determined in various ways the response of P. alata to changing environmental conditions. Overall P. alata appeared to be well adapted to the natural variability in light availability and CO2(aq) concentration of the modern Southern Ocean. Nevertheless, our results showed that P. alata is susceptible to future changes in inorganic carbon concentrations in the Southern Ocean.

Size exclusion chromatogram of the Tannermoor 2009 sample after saltout experiments

Samples from a pristine raised peat bog runoff in Austria, the Tannermoor creek, were analysed for their iron linked to natural organic matter (NOM) content. Dissolved organic carbon < 0.45 µm (DOC) was 41 to 64 mg/L, iron 4.4 to 5.5 mg/L. Samples were analysed applying asymmetric field flow fractionation (AsFlFFF) coupled to UV-Vis absorption, fluorescence and inductively coupled plasma mass spectrometry (ICP-MS). The samples showed an iron peak associated with the NOM peak, one sample exhibiting a second peak of iron independent from the NOM peak. As highland peat bogs with similar climatic conditions and vegetation to the Tanner Moor are found throughout the world, including areas adjacent to the sea, we examined the behaviour of NOM and iron in samples brought to euhaline (35 per mil) conditions with artificial sea salt. The enhanced ionic strength reduced NOM by 53% and iron by 82%. Size exclusion chromatography (SEC) of the samples at sea-like salinity revealed two major fractions of NOM associated with different iron concentrations. The larger one, eluting sharply after the upper exclusion limits of 4000-5000 g/mol, seems to be most important for iron chelating. The results outline the global importance of sub-mountainous and mountainous raised peat bogs as a source of iron chelators to the marine environment at sites where such peat bogs release their run-offs into the sea.

Benthic anammox and dentrification rates measured in a slurry incubation experiments at four different stations in the Arabian Sea off Pakistan during the METEOR cruise M74/2 in 2007

Vertical distributions of benthic denitrification and anammox rates within the sediment were estimated from slurry incubation experiments. Rates were used to calculate the contribution of anammox and denitrification to the total N-loss. Briefly, MUC sediment cores were sliced in 2 cm intervals and the sediment was diluted and incubated with degassed bottom water in a gas tight bag. After pre-incubating the bags for 2 h, 15N-labeled substrates were injected into the bags and the slurries were thoroughly mixed. Incubations were performed in the dark at in situ temperatures. The N2 isotope ratio (28N2, 29N2, and 30N2) was determined by gas chromatography-isotopic ratio mass spectrometry (VG Optima, Micromass) and calculated according to Kuypers et al. (2005) and Holtappels et al. (2011), respectively.Furthermore, total organic carbon and nitrogen concentrations were measured of core sediment layers corresponding to those used for rate measurements. Concentrations of organic carbon and nitrogen were determined by combustion/gas chromatography (Carlo Erba NA-1500 CNS analyzer) of dried sediment samples after acidification. The same sediment layer were also used to extract nucleic acids. The concentrations of the DNA in the samples were measured spectrophotometrically with a NanoDrop instrument (Thermo Fisher Scientific Inc.). The biomarker functional gene nirS, encoding the cd1-containing nitrite reductase, for both denitrifiers and marine anammox bacteria were quantified with real-time PCR, using the primers cd3aF/R3cd (5'-GTSAACGTSAAGGARACSGG-3' (Michotey et al., 2000)/5'-GASTTCGGRTGSGTCTTGA-3'; Throback et al., 2004) and Scnir372F/Scnir845R (5'-TGTAGCCAGCATTGTAGCGT-3'/5'-TCAAGCCAGACCCATTTGCT-3'; Lam et al., 2009).