README file for the dataset in

Frainer, A & Tiegs, S. (2022) A stream-to-sea experiment reveals inhibitory effects of freshwater residency on organic-matter decomposition in the sea. Limnology and Oceanography Letters, DOI: 10.1002/lol2.10261

Table 1. Description of the fields needed to describe the creation of your dataset.
Title of dataset	Stream-to-Sea cotton strip data from Kaldfjord	
URL of dataset	https://github.com/andre-frainer/Stream-to-Sea.git	
Abstract	We assessed organic-matter decomposition in marine and freshwater sites and simulated the downstream transport of organic matter from freshwaters to the global ocean by translocating experimental materials to marine sites approximately half-way through the freshwater incubation period. We observed significantly faster decomposition of organic matter in the sea relative to the stream and a negative priming effect due to stream incubation, evidenced by slower decomposition rates of organic matter transplanted to the sea half-way through the experiment. 	
Keywords	Cotton strips; organic matter decomposition; stream-to-sea	
Lead author for the dataset 	André Frainer	
Title and position of lead author	Principal investigator	
Organization and address of lead author	Faculty of Biosciences, Fisheries and Economy, UiT The Arctic University of Norway, Tromsø, Norway
Norwegian Institute for Nature Research (NINA), Framsenteret, Tromsø, Norway	
Email address of lead author	andre.frainer@nina.no	
Additional authors or contributors to the dataset 	Scott Tiegs	
Organization associated with the data	Same as main author	
Funding	none	
License	CCBY	
Geographic location – verbal description	Kaldfjord, near Tromsø, northern Norway, at the mouth of Urdalelva and the nearby shore of Kaldfjord.	
Geographic coverage bounding coordinates	69°44' N 18°37' E	
Time frame - Begin date	08.10.2017	
Time frame - End date	18.11.2017	
General study design	See Frainer & Tiegs 2021 for detailed information about the study design,	
Methods description	We deployed cotton strips (8 x 2.5 cm) made from a single bolt of ‘Artist’s fabric’ (Fredrix-brand heavy-weight unprimed 12-oz. cotton, Style #548, Fredrix, Lawrenceville, GA, USA	
Laboratory, field, or other analytical methods	See Frainer & Tiegs 2021 for detailed information about field and lab work.
	
Taxonomic species or groups	Cotton strips are analyzed for the loss of tensile strength (the resistance of the material to tearing under strain), a process that reflects the microbial catabolism of cellulose.	

Table 2. Data dictionary: description of the variables (i.e., columns) in EACH dataset. 
Dataset filename: isotopes cotton strips Kaldfjord.csv
Dataset description: explain what is in this dataset
Column name	Description	Units	Code explanation	Data format	Missing data code	
Ecosystem	Same as ‘treatment’, in three levels: ‘stream’, ‘sea’, and ‘stream-to-sea’	Stream, sea, stream-to-sea		factor		
Time	Inubation time in days	Days		Numeric		
D15N	Delta 15 Nitrogen isotope values	Isotope ratio		Numeric		
N.µg	Amount of total nitrogen in the sample	µg		Numeric		
amountN.mg	Amount of biomass used for analyses	mg		Numeric		
D13C	Delta 15 Carbon isotope values	Isotope ratio		Numeric		
C.µg	Amount of total carbon in the sample	µg		Numeric		
amountC.mg	Amount of biomass used for analyses	mg		Numeric		
N.perc	Percentage of N given total biomass in the sample (N.µg/amount.mg)*1000	Percentage		Numeric		
C.perc	Percentage of C given total biomass in the sample (C.µg/amount.mg)*1000	percentage		Numeric		

Dataset filename: Stream-to-Sea cotton strip data.csv
Dataset description: Dataset containing results from cotton strip tensile strength measurements, including data on water temperature and time during incubation, and the rates of decomposition.
Column name	Description	Units	Code explanation	Data format	Missing data code	
replicate	Each group of samples had one identifier					
treatment	Three levels to differentiate between ‘control’, ‘fresh’, or ‘marine’			Factor		
Treatment	Two levels to differentiate between ‘Fresh’ and ‘Marine’			Factor		
Time	Time of incubation in days	Number of days		Numeric		
temperature	Sum of the daily average temperature, in degree Celsius	Sum of daily average temperature		Numeric		
tensileStrength	Resistance of the material to tearing under strain			Numeric		
kday	Decomposition rates by time	k	k =  ln(St/S0)/t, where k is the tensile decomposition rate, St is the tensile strength at t, S0 is the initial tensile strength (control), and t is time in days	Numeric		
ktemp	Decomposition rates by the sum of daily average temperature	k	k =  ln(St/S0)/t, where k is the tensile decomposition rate, St is the tensile strength at t, S0 is the initial tensile strength (control), and t is the sum of daily average water temperature	Numeric		

Table 3. Data provenance
The dataset is original.