Realm: Marine
Climate: Temperate/Tropical
Biome: Multiple ecoregions
Central latitude: 12.696601
Central longitude: -29.903677
Duration: 11 years, from 1992 to 2002

37524 records

576 distinct species

Across the time series Flagellate sp4 is the most frequently occurring species

Methods

1. Sampling methods:Microplankton abundanceData analysed were collected from 1992 to 2002 at 788 sites. See Fig. 1 and Table 1 for a detailed site description. Seawater samples were collected from different depths (most of them in surface waters) from CTD Niskin bottles. For later microplankton cell counts. it is very important to handle seawater with care. as some organisms are very sensitive to turbulence (Gifford and Caron 2000). Water samples were taken from the Niskin bottle and immediately preserved with 1–5 % acid-Lugol's iodine solution (Throndsen 1978). Samples were labelled and stored in cold. dark conditions during transportation to the laboratory.NutrientsWe only have in situ nutrients data for AMT cruises. Samples were taken from the underway pumping system between stations. from vertical profiles at each station. or both. However. we only included samples obtained during the daily CTD casts coincident with the microplankton sampling. Water samples from the CTD/Rosette system (SeaBird) were sub-sampled into clean Nalgene bottles. Sample analysis was completed within 3 h of sampling. so no samples were stored.Other variablesFor Chlorophyll. between 200 and 300 mL of sea water from each depth in the water column were sequentially filtered through 0.2 µm. 2 µm and 20 µm polycarbonate filters. Chl a was extracted from filters in 90% acetone at 20°C for 12 to 24 hours. Samples were measured on a Turner 10-AU fluorometer calibrated with pure Chl a.Temperature and PAR were obtained either from CTD data or underway records from the ship. For those stations where it was impossible to obtain data. these were retrieved from satellite data.2. AnalysisMicroplankton abundanceMicroplankton identification and cell counts was carried out by Derek S. Harbour at the Plymouth Marine Laboratory using inverted microscopy following the Utermöhl technique (Utermöhl 1958). The ''Water quality - Guidance standard for routine microscopic surveys of phytoplankton using Utermöhl technique'' (BS EN 15204:2006) was followed:Microplankton samples. preserved in Lugol's iodine and formalin. were settled in sedimentation chambers while acclimatized to room temperature. to ensure a random distribution of cells. After this. sample bottles were rotated to help re-suspension and separation. Sub-samples with volumes between 10 and 256 mL were later transferred to plankton settling chambers. A variable area of the chamber bottom was counted under the microscope. The size of that area varies with species and abundance and under some circunstances different species were counted in different settled volumes to obtain consistency and reproducibility in the counts. At least 100 cells of each of the more abundant species were counted. Settlement duration varied between 4h cm-1 for Lugol's iodine and 16 h cm-1 for formaldehyde samples.Once the settling process finished. cells were identified. where possible. to species/genus level and assigned to different functional groups: Flagellates. Heterotrophic flagellates. Diatoms. Coccolithophores. Dinoflagellates. Heterotrophic dinoflagellates. and Ciliates. It should be noted that heterotrophic refers to organisms that do not contain pigments.Abundance data for each species at each station was calculated in cells per mL. Dimensions of individual species were measured in µm units using digital measurements and calibrated against an ocular micrometer. Using the corresponding geometric shapes. these measurements were converted to volume using the (Kovala and Larrance 1966) methodology. Once this was done. cell volumes were converted to carbon (pg cell-1) using the formulae of Menden-Deuer and Lessard (2000).Since all the plankton counts were obtained by light inverted microscopy they do not include pico-cyanobacteria. like Prochlorococcus and Synechococcus. The database adequately samples the microplankton size range and part of the nanoplankton abundance. small eukaryotes are also too small to be identified to the species level by light-microscopy. The Utermöhl technique is restricted to cells larger than 10 µm (within the nanoplankton size range). Smaller cells do not settle quantitatively even after Lugol's iodine addition and cells are too small to classify to the species level.NutrientsTo analyse nutrients. a Technicon AAII (four-five channel depending on the cruise) segmented-flow auto-analyser was used. Protocols used were different for each nutrient: phosphate and silicate were analysed as described by Kirkwood (1989). Nitrate and nitrite was analysed using a modified version of Grasshoff's method (Grasshoff 1976). as described by Brewer and Riley (1965). These were measured as nirate plus nitrite. since the nitrate was determined as nitrite using a copper-cadmium reduction column to reduce it to nitrite. We later calculated nitrate as the difference between the nitrite measure and the nitrite plus nitrate measure. Ammonium was measured only in cruise AMT6. The chemical methodology used was the described by (Mantoura and Woodward 1983). All results are presented as µmol L-1 of the elements nitrogen. phosphorus and silica. Data set of marine microplankton species abundances at 788 stations. collected on different oceanographic cruises between 1992 and 2002. This database consists of abundances (cells/mL) for each species at each station and depth Unit of abundance = IndCountDec, Unit of biomass = NA

Citation(s)

Sal, S., López-Urrutia, Á., Irigoien, X., Harbour, D. S. & Harris, R. P. (2013) Marine microplankton diversity database. Ecology, 94, 1658. http://dx.doi.org/10.1890/13-0236.1.