FTIR-ATR Spectra of Pelagic Sargassum Specimens under Different Flash-Freeze Timing and Cryogenic Storage Conditions

About the data set origin

The dataset comprises ATR-FTIR spectral CSV files of pelagic Sargassum specimens, including S. fluitans III (labeled "flu3" in the sample ID), S. natans I (labeled "nat1"), and S. natans VII (labeled "nat8"). The specimens were collected from three sites on the south Mexican Caribbean coast: Mahahual (labeled "Ma"), Xcalak (labeled "Xk"), and Xahuayxol (labeled "Xa"). The experimental design includes a treatment condition based on the timing of flash-freezing: the fresh group (labeled d00) and the lab group (labeled d01). The fresh group was flash-frozen on the shore and stored under cryogenic conditions, while the lab samples were flash-frozen upon arrival at the laboratory facilities. The sample IDs are listed in Table 1.

About the Equipment and Data Acquisition

All ATR-FTIR analyses were conducted using a Nicolet iS5 from Thermo Scientific (USA), equipped with an iD7 accessory and a ZnSe crystal plate. The Thermo Scientific OMNIC software was used for the analysis. Background noise was removed from all spectra. The spectral acquisition range spanned from 500 to 4000 cm⁻¹, with 32 scans per sample and a spectral resolution of 4 cm⁻¹, resulting in a data spacing of 0.482 cm⁻¹. Each sample was analyzed in triplicate.

Table 1. Sample ID and size for the flash-freeze comparison dataset

Site

Morphotype

Flash-freeze treatment

Samples collected

Samples read in triplicate

Mahahual (Ma)
S. fluitans III (flu3)
Fresh (d00)
2
6

Lab (d01)
2
6

S. natans I (nat1)
Fresh (d00)
2
6

Lab (d01)
2
6

S. natans VIII (nat8)
Fresh (d00)
2
6

Lab (d01)
2
6

Xahuayxol (Xa)
S. fluitans III (flu3)
Fresh (d00)
1
3

Lab (d01)
2
6

S. natans I (nat1)
Fresh (d00)
1
3

Lab (d01)
2
6

S. natans VIII (nat8)
Fresh (d00)
1
3

Lab (d01)
2
6

Xcalak (Xk)
S. fluitans III (flu3)
Fresh (d00)
1
3

Lab (d01)
2
6

S. natans I (nat1)
Fresh (d00)
1
3

Lab (d01)
2
6

S. natans VIII (nat8)
Fresh (d00)
1
3

Lab (d01)
2
6

Total 
30
90