Description: This data is part of the BMBF projects CUSCO (Coastal Upwelling Systems in a Changing Ocean) and BioTip subproject Humboldt Tipping. Data was collected during cruise number MSM80 with research vessel Maria S. Merian from 23.12.2018 - 30.01.2019 (from Panama to Valparaiso) in the Humboldt Upwelling system off the Eastern Tropical south Pacific. Samples were taken by CTD- rosette sampler from different depths and analysed onboard for dissolved inorganic nutrients and total dissolved nutrients. Triplicate nutrient samples were analysed for concentrations with an autosampler (XY-2 autosampler, SEAL Analytical) and a continuous flow analyzer (QUAAtro Autoanalyzer, SEAL Analytical) using standard colorimetric and flourometric methods by Kastriot Qelaj. Dissolved organic nutrients were calculated as the difference of the two for respective nitrogen and phosphorous nutrients. Phosphate was measured according to Murphy and Riley (1962). Ammonium was measured fluorometrically based on Holmes et al. (1999). An empty cell means that corresponding nutrient samples were not taken for the respective depth.

Description: Size fractionated primary productivity rate measurements through 14C radioisotope incorporation rates from a KOSMOS mesocosm experiment carried out in the frame work of the Ocean Artificial Upwelling project. The experiment was performed in the North-East Atlantic Ocean off the coast of Gran Canaria in autumn 2018 and lasted for 39 days. In this study we investigated the effect of different intensities of artificial upwelling combined with two upwelling modes (recurring additions versus one singular addition) on the phytoplankton community. Data shown includes production rates of dissolved organic carbon, particulate organic carbon in 3 size fractions (0.2-2 µm, 2-20 µm, 〉20 µm) and total organic carbon.

Description: Export data from the mesocosm experiment conducted in the Canary Islands in autumn 2019. Sinking matter was collected in 2-days intervals over the course of 33 days from the mesocosm sediment traps (4 m depth). Sediment samples were processed and subsampled for duplicate measurements of particulate organic carbon (POC), nitrogen (PON), phosphorus (POP) and biogenic silica (BSi). Elemental mass fluxes in µmol L-1 were calculated by normalizing to the mesocosm volume. They were then either normalized to the time between sample collection (48 h) to obtain daily mass fluxes (µmol L-1 d-1), or added up to obtain cumulative mass fluxes (µmol L-1). Another set of sediment subsamples was analyzed for particle sinking velocities, sizes and porosities (bidaily) and microbial remineralization rates (every 4 days).

Description: This data is part of the BMBF projects CUSCO (Coastal Upwelling Systems in a Changing Ocean) and BioTip subproject Humboldt Tipping. Here we report water column nitrogen fixation, carbon fixation rates and particulate organic matter composition from the upper 300 m. Data was collected during cruise number MSM80 with research vessel Maria S. Merian from 23.12.2018 - 30.01.2019 (from Panama to Valparaiso) in the Humboldt Upwelling system off the Eastern Tropical south Pacific. Samples were taken by CTD- rosette sampler from different depths, injected with 15N labelled N2 gas based on the modified dissolution method (Großkopf et al., 2012 and Mohr et al., 2010) and additionally 13C labeled sodium bicarbonate. Samples were incubated for 24 hours at light intensities that resemble the in situ light conditions. After incubation a volume of the sample (20 - 1500 ml) was filtered onto a pre-combusted Whatman GF/75 filter. Filters were frozen, transported to the institute on dry ice and measured on a mass spectrometer for Delta15N and 13C (Delta V Advantage Isotope Ratio MS, ThermoFisher) with the ConFlo IV interface (ThermoFisher). Nitrogen fixation rates were calculated based on Montoya et al (1996) while carbon fixation rates were calculated based on the equation by Slawyk et al. (1977). Limits of detection (LOD) and minimum quantifiable rates (MQR) for Nitrogen fixation rates were calculated according to the criteria described by White et al. (2020) and standard error propagation methods described in Gradoville et al. (2017) respectively. POP and Biogenic silica concentrations were measured spectrophotometrically following Hansen and Koroleff (1999).

Description: This data is part of the BMBF projects CUSCO (Coastal Upwelling Systems in a Changing Ocean) and BioTip subproject Humboldt Tipping. The file contains total dissolvable trace metal concentrations (Fe, Cd, Ni, Cu, Zn and Co) from various depths of sampled stations. Trace metal concentrations were determined via Inductively coupled plasma mass spectrometry (ICP-MS, Element XR, ThermoFisher Scientific) after pre-concentration as per Rapp et al. (2017).

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report carbon and nitrogen uptake rates by phytoplankton collected during a 35-day experiment where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). Samples were spiked with 13C labelled sodium bicarbonate and 15N labelled potassium nitrate. Samples were incubated for 24 hours at light intensities that resemble the light conditions in the mesocosms. After incubation a subsample (150-1000 ml) was filtered onto a 0.7 µm pre-combusted glass-fiber filters (GFF, Whatmann). The filters were acidified, then dried in the oven at 60 °C and later measured using an elemental analyzer (Flash IRMS, ThermoFisher) connected to a mass spectrometer (Delta V Advantage Isotope Ratio MS, ThermoFisher) with the ConFlo IV (ThermoFisher). Carbon and nitrogen uptake rates were calculated based on Slawyk et al. (1977, DOI:10.4319/lo.1977.22.5.0925) and Shiozaki et al. (2009, DOI:10.3354/meps07837) respectively.

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report the dissolved organic carbon and total dissolved nitrogen concentrations during a 35-day experiment, where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). Sub-samples (60 mL) were syringe filtered through two pre-combusted glass fiber filters (5 h, 450 °C). To reduce clogging, one 3.1 µm GMF filter was placed on top of a 0.7 µm GFF filter. The filtrate was acidified to pH 2 with 25% HCl before storing at -20°C until analysis. The DOC and TDN concentrations were measured using a TOC-VCPH analyser (Shimadzu). Instrument accuracy was evaluated by comparison against a deep Atlantic seawater reference (Consensus Reference Material project: D. Hansell, University of Miami, USA).

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report particulate organic matter concentrations collected during a 35-day experiment where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). Samples (150-1000 ml) were filtered onto a 0.7 µm pre-combusted glass-fiber filters (GFF, Whatman). The filters were acidified and then dried in the oven at 60 °C for 24 hours and total particulate carbon (TPC), particulate organic carbon (POC) and nitrogen (PON) content were measured using a CN analyzer (Euro EA3000, HEKAtech GmbH, Wegberg, Germany). POP filters were autoclaved for 30 min in 100 mL Schott Duran glass bottles using an oxidizing decomposition solution (Merck, catalogue no. 112936) to convert organic phosphate to orthophosphate. Phosphate concentrations were determined spectrophotometrically following Hansen and Koroleff (1999; doi:10.1002/9783527613984.ch10).

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report pigment concentrations and the phytoplankton community composition based on CHEMTAX analysis during a 35-day experiment, where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). To obtain pigment concentrations 0.15 – 1L of water sampled from the water column were filtered onto glass-fiber filters (precombusted at 450°C for 6h, GFF, 0.7 µm nominal pore size, Whatman) using a low vacuum of 200 mbar. Afterwards the filters were stored in cryovials at -80°C until analysis of photosynthetic pigments using reverse-phase high-performance liquid chromatography (HPLC) following (Barlow et al., 1997; doi:10.3354/meps161303) as described by (Paul et al., 2015; doi:10.5194/bg-19-5911-2022). The phytoplankton community composition was calculated with CHEMTAX, which classifies phytoplankton taxa based upon taxon-specific pigment ratios (Mackey et al., 1996; doi:10.3354/meps144265). The values for the Peruvian upwelling system determined by (DiTullio et al., 2005; doi:10.4319/LO.2005.50.6.1887) as described by (Meyer et al., 2017; doi:10.3389/fmars.2017.00001) were used as pigment ratios. As phytoplankton microscopy revealed high abundances of the raphydophite Fibrocapsa japonica, the initial pigment matrix was complemented by ratios for F. japonica from (Laza-Martinez et al., 2007; doi:10.1093/plankt/fbm069) from the Atlantic.

Description: Microzooplankton (microZP, protists) and mesozooplankton (mesoZP, metazoans) abundances and biomass as well as presence of domoic acid (DA, phycotoxin) during the mesocosm experiment in the Canary Islands in autumn 2019. Depth-integrated (0-2.5m) water samples were taken over the course of 33 days, in 2-day intervals for microZP and mesoZP and 4-day intervals for DA. MicroZP was assessed by Utermöhl light microscopy and its biomass estimated using biovolume to carbon conversion factors from the literature. MesoZP samples were split into three size fractions (55-200, 200-500 and 〉500 µm), preserved with 70% ethanol and assessed under a stereo microscope. For biomass, mesoZP were measured in an element analyser. MesoZP data is provided for copepods only (dominant group) and all metazoan zooplankton combined (mainly copepods and appendicularians). For DA, particulate matter was filtered (〉0.7µm) and analysed via liquid chromatography and tandem mass spectrometry. The upwelling treatment started on day 6. Methodological details in Goldenberg et al. (doi:10.3389/fmars.2022.1015188) and Goldenberg et al. (under review).