Bio-optical observations of the Baltic Sea and coastal areas, 2008-2012

This a dataset of optical-biogeochemical measurement results was collected during 2008-2012 as part of spring and summer cruises with R/V Aranda as well as from flow-through water samples taken with the Ferrybox system on M/S Finnmaid. The majority of observations were made in the Gulf of Finland, Baltic Proper, Archipelago Sea, and Gulf of Bothnia in the Baltic Sea. A number of riverine and inshore observations are also included. The data collection is owned by the Finnish Environment Institute SYKE and made available under a CC-BY-NC licence. 

Detail on methods and protocols are provided in the following papers 

Simis, Stefan GH; Ylöstalo, Pasi; Kallio, Kari Y; Spilling, Kristian; Kutser, Tiitt. 2017. Contrasting seasonality in optical-biogeochemical properties of the Baltic Sea. PLoS One 12(4), e0173357. https://doi.org/10.1371/journal.pone.0173357

Ylöstalo, Pasi; Seppälä, Jukka; Kaitala, Seppo; Maunula, Petri; Simis, Stefan. 2016. Loadings of dissolved organic matter and nutrients from the Neva River into the Gulf of Finland–Biogeochemical composition and spatial distribution within the salinity gradient. Marine Chemistry 186, 58-71. https://doi.org/10.1016/j.marchem.2016.07.004

A large number of individuals took part in these bio-optical research cruises over the years. The authors of this dataset are particularly grateful to the contributions by international visitors, students and volunteers taking part in one or more cruises, as well as crew and support staff operating the research vessel and ship-of-opportunity. 

Variables included in the dataset include: 

Column name
unit/format
Description

Secchi
m
Secchi disk depth

AirTemp(38)
°C, 01H
Air temperature from ship weather channel 38, 1-h average

SeaTemp(42)
°C, 01H
Sea temperature from ship weather channel 42, 1-h average

WindSpeed(92)
m/s, 10M
Wind speed from ship weather channel 92, 10-min average

WindDir(96)
°, 10M
Wind direction from ship weather channel 96, 10-min average

Salinity(104)
PSU, 01H
Salinity from ship weather channel 104, 1-h average

Rel.humid(54)
%, 01H
Relative humidity from ship weather channel 54, 1-h average

Chla
mg/m3
Chlorophyll-a concentration (cold ethanol extraction and calibrated fluorescence)

TSM_avg
mg/L
Total Suspended Matter Dry Weight, Average

OSM_avg
mg/L
Dry weight of Organic fraction of TSM, Average

ISM_avg
mg/L
Dry weight of Inorganic fraction of TSM, Average

DOC_avg
µM
Dissolved Organic Carbon concentration, Average

TDN_avg
µM
Total Dissolved Nitrogen concentration, Average

NH4
µM
Ammonium concentration

NO32
µM
Nitrate-Nitrate concentration

NO2
µM
Nitrite concentration

PO4
µM
Phosphate concentration

SiO4
µM
Silicate concentration

TN
µM
Total nitrogen concentration

TP
µM
Total phosphorous concentration

pH
pH
pH value

Temp_CTD
°C
Water temperature measured by Seabird CTD on sampling rosette

Salinity_CTD
SSU
Salinity measured by Seabird CTD on sampling rosette

POC
µM
Particulate Organic Carbon concentration, Average

PON
µM
Particulate Organic Nitrogen concentration, Average

POP
µM
Particulate Organic Phosphorus concentration, Average (30.973762 g/Mol)

Turbidity
PSU
Turbidity

aCDOM
m^-1
spectral absorption coefficient of coloured dissolved organic matter

CloudCover
0-1
Fraction (0-1) of cloud cover assesed from photos taken in the field.

Kd
m^-1
spectral Vertical diffuse downwelling irradiance coefficient

a_nap
m^-1
spectral absorption coefficient by non-pigmented fraction of suspended matter

a_tsm
m^-1
spectral absorption coefficient by suspened matter

R0
-
spectral Subsurface Irradiance Reflectance

pigments
mg/m3
Chlorophyll and other pigments extracted and quantified using a combination of calibrated fluorometry and HPLC