Large benthic foraminifera, sediment heavy metals, and coastal water environmental parameters in West Likupang, North Sulawesi, Indonesia

Description

Sample points (Table 1): Three sampling points were selected to represent distinct coastal environments: (1) a tourist area, (2) a mangrove area, and (3) a village area (Figure 1, Table 1). Species of large benthic foraminifera (Tables 2 and 3): This dataset documents the species and number of individuals (raw counts) of LBF collected from the coastal waters of West Likupang. A total of 147 species were identified, comprising 71 species (48%) represented by more than one specimen (Table 2) and 76 singleton species (52%) (Table 3), representing an aggregate of 326 specimens (250 listed in Table 2 and 76 listed in Table 3). Genus richness data (Tables 4 and 5): These tables present genus-level diversity of the large benthic foraminifera (LBF), documenting 83 genera (20 with more than one species represented, Table 4, and 63 with only one species represented, Table 5). Metal concentration in the sediments (Table 6): These data include the concentrations of seven metals (Cd, Cu, Pb, Sn, Zn, As, and Hg) measured in sediment samples collected from the three sampling points. Cadmium (Cd), Pb, and Hg were detected at all sampling points, with mean ± SD values of 0.04 ± 0.03 mg/kg dry weight, 1.50 ± 0.96 mg/kg dry weight, and 0.18 ± 0.01 mg/kg dry weight, respectively. Copper (Cu) and As were detected at two of the three points, with mean concentrations of 0.83 ± 0.29 mg/kg dry weight and 1.83 ± 1.26 mg/kg dry weight, respectively. Tin (Sn) was detected at only one sampling point (9.00 mg/kg dry weight), whereas Zn remained below the detection limit of 1.00 mg/kg at all sampling points. When concentrations were below the detection limit (nd values in Table 6) means and standard deviations were calculated by substituting the nd values with half the detection limit (MDL/2). This approach provides a conservative approximation of central tendency and is widely used in environmental data analysis. However, there are limitations associated with this approach, including potential overestimation or underestimation of true means, particularly in small datasets; therefore, these summary statistics should be interpreted with caution. Furthermore, the reported mean ± SD values only reflect variation among sampling points and do not account for statistical variability at each sampling locality or analytical errors. Environmental data (Table 7): This dataset includes measurements of key water quality parameters at the three sampling points. Water temperature ranged from 29.2 to 30.0°C, with a mean ± SD of 29.57 ± 0.41°C, which is typical for tropical coastal waters of Indonesia. Salinity was relatively stable at 34.5 ppt. Dissolved oxygen (DO) varied considerably from 7.95 to 11.45 mg/L, with a mean ± SD of 9.23 ± 1.89 mg/L. The pH ranged from 7.18 to 8.20 (mean ± SD: 7.76 ± 0.52), indicating typical slightly alkaline tropical marine conditions.

Steps to reproduce

In July 2024, single surface sediment samples (non-replicated) were collected via SCUBA from three coastal sites (tourist, mangrove, village) at 3–5 m depth. The design lacks within-site replication, precluding statistical comparisons. Each sample targeted the top 1–2 cm (50 g wet sediment) for benthic foraminifera, was homogenized, and split: one portion preserved in Rose Bengal/ethanol (for future live/dead differentiation, not analyzed here), the other for total (live+dead) assemblage analysis. For foraminifera analysis, samples were washed through 63 µm sieve, air-dried, and counted under microscope. Only 326 individuals were counted across all three sites (below typical 300/site target). The total assemblage was analyzed, providing species inventory but not distinguishing living from dead individuals; ecological indices reflect overall biodiversity, not solely current conditions. Taxonomic identification used morphology, WoRMS, World Foraminifera Database, and Indo-Pacific literature. Some taxa reported as “sp.” Heavy metal analysis (Cd, Cu, Pb, Sn, Zn, As, Hg) used EPA 3050B digestion and ICP-MS (Cd, Cu, Pb, Sn, Zn, As) and CVAFS (Hg). QC recoveries ranged 92–119% (acceptable 80–120%). MDLs: Cd 0.02 mg/kg; Cu, Sn, Zn, As 1.00 mg/kg. Blanks below MDLs.

Institutions

• Sam Ratulangi University

  North Sulawesi, Manado

Categories

Funders

• Sam Ratulangi University (UNSRAT) through its PNBP scheme in 2024 (Contract No. 401/UN12.27/LT/2024) and partially supported by the Philip Sandford Boone Chair in Paleontology at the University of California, Berkeley (CRM).

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