Zooplankton abundance data during 2013 in the Bulgarian Black Sea

Data Records

The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 84 records.

2 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.

Versions

The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Kremena Stefanova and Elitsa Stefanova; Institute of Oceanology, Bulgarian Academy of Sciences (IO-BAS); (2025): Zooplankton abundance data during 2013 in the Bulgarian Black Sea.

Rights

Researchers should respect the following rights statement:

This work is licensed under a Creative Commons Attribution Non Commercial (CC-BY-NC 4.0) License.

GBIF Registration

This resource has not been registered with GBIF

Keywords

Sampling event; Sampling event

Contacts

Geographic Coverage

Bulgarian Black Sea area

Taxonomic Coverage

Mesozooplankton and macrozooplankton

Temporal Coverage

Project Data

The zooplankton data is a part of long-term monitoring programs under the Water Framework Directive (WFD).

The personnel involved in the project:

Sampling Methods

Zooplankton samples are collected by vertical plankton Juday net with closing mechanism (0.1 m2 mouth opening area, 150 μm mesh size), from 2 meters above the bottom or oxygen minimum zone to the surface at integral sampling layers or districted layers depending of water stratification and thermocline depth (Alexandrov et al., 2020).

Method step description:

1. The Juday net is hauled vertically with a speed not exceeding 1 m/s (UNESCO, 1968). After taking the net onboard, the content of cod-end is collected. Before zooplankton sample preservation, the gelatinous species (Aurelia aurita, Pleirobrachia pileus, Mnemiopsis leidyi, Beroe ovata) are removed, rinsed, measured and counted on board (Shiganova et al., 2021). The samples are preserved in final 4% formalin solution buffered to pH 8-8.2 with disodiumtetraborate (borax) (Na2B403·10 H20) (Alexandrov et al., 2020). Filtered water volume is calculated based on length of tow and area of mouth: V=S·d, where V [m3] is the volume of water filtered by the net, S [m2] is the mouth surface area, and d [m] is the distance of the tow. In order to save the filtration capacity, after each cruise the net must be washed with detergent in warm fresh water. After storage for at least 20 days in a cool and dark place, in the laboratory the samples are concentrated to 100-150 ml and settled before being divided into sub-samples. Dimov’s method (1959) is used for quantitative assessment (abundance) and qualitative (taxonomic structure) processing of sub-samples examined by using an Olympus SZ30 Stereoscopic Zoom Microscope. Large scale zooplankters (Calanus euxinus, Chaetognaths, Decapoda larvae, Pisces eggs and larvae, etc.) are counted in the whole sample. Species were identified according to Morduhay-Boltovskoy (1968, 1969, 1972) manuals. Taxonomic nomenclature is according to the on-line data-base of World Register of Marine Species (WoRMS) http://www.marinespecies.org/

Additional Metadata