Polysaccharide Hydrolase activities in Danish coastal seawater and sediments under varying hydrostatic pressures on samples collected in September 2023
Project
| Contributors | Affiliation | Role |
|---|---|---|
| Arnosti, Carol | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Principal Investigator |
| Lloyd, Chad | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Scientist |
| Ghobrial, Sherif | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Data Manager |
| Mickle, Audrey | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Abstract
Polysaccharide used for incubation:
- ara = arabinogalactan
- chn = chondroitin sulfate
- fuc = fucoidan
- lam = laminarin
- man = mannan
- pul = pullulan
- xyl = xylan
- Imported "20250116_FlaRates_HELS_All_FINAL.csv" into the BCO-DMO system
- Replaced ammended with amended in all fields and parameter names
- Replaced all time values at submitter's request from 3:50 to 9:50 local time
- Converted "date" to YYYY-MM-DD format
- Added additional ISO_DateTime_UTC field using local time and date
- Renamed "time" to "time_local_CEST" to indicate timezone
- Exported file as "963382_v1_polysaccharide_hydrolase.csv"
| File |
|---|
963382_v1_polysaccharide_hydrolase.csv (Comma Separated Values (.csv), 27.43 KB) MD5:71b1ed92b110a824e201f138a3ebc4be Primary data file for dataset ID 963382, version 1 |
| Parameter | Description | Units |
| latitude | Latitude of sampling site, Positve is North. | decimal degrees |
| longitude | Longitude of sampling site, Positive is East. | decimal degrees |
| ISO_DateTime_UTC | Datetime of collection in ISO format, UTC. | unitless |
| date | Date of sample collection. | unitless |
| time_local_CEST | Time of sample collection in Central European Summer Time (CEST). | unitless |
| depth_actual | Depth where sample was collected. Depth of water column was 26 m. | m |
| sample_type | The type of sample, whether it was incubated using water from the bulk water column, sediments, amended with Thallasiosira weissflogii for 0 days (LV_day0), amended with Thallasiosira weissflogii for 7 days (LV_day7), or dissolved enzymes (<0.2 µm) after 7 days amended with Thallasiosira weissflogii. | unitless |
| in_situ_T | Temperature of the samples in-situ. | degrees Celsius |
| in_situ_S | CTD salinity measurements of the samples in-situ. | psu |
| incubation_T | Temperature the samples were incubated at for enzyme activity measurements. | degrees Celsius |
| unamended_amended | Whether the sample was amended with Thalassiosira weisflogii or not. | unitless |
| pressure | What pressure the incubation was pressurized to. | MPa |
| substrate | Polysaccharide used for incubation: ara = arabinogalactan, chn = chondroitin sulfate, fuc = fucoidan, lam = laminarin, man = mannan, pul = pullulan, xyl = xylan | unitless |
| timepoint_number | The timepoint number sampled for each incubation. | unitless |
| timepoint_days | The amount of time that has elapsed at each timepoint. | days |
| rate_x_kc | The kill-corrected hydrolysis rate for the kill-control (i.e., ratekc - ratekc). | nmol L-1 hr-1 |
| rate_1_kc | The kill-corrected hydrolysis rate for the first replicate (i.e., raterep1 - ratekc). | nmol L-1 hr-1 |
| rate_2_kc | The kill-corrected hydrolysis rate for the second replicate (i.e., raterep2 - ratekc). | nmol L-1 hr-1 |
| rate_3_kc | The kill-corrected hydrolysis rate for the third replicate (i.e., raterep3 - ratekc). | nmol L-1 hr-1 |
| rate_mean_kc | The average kill-corrected hydrolysis rate for all replicates. | nmol L-1 hr-1 |
| rate_sd_kc | The standard deviation of the kill-corrected hydrolysis rates for all replicates. | nmol L-1 hr-1 |
| Dataset-specific Instrument Name | CTD |
| Generic Instrument Name | CTD - profiler |
| Dataset-specific Description | Water was collected using a Niskin bottle and salinity values are from the CTD. |
| Generic Instrument Description | The Conductivity, Temperature, Depth (CTD) unit is an integrated instrument package designed to measure the conductivity, temperature, and pressure (depth) of the water column. The instrument is lowered via cable through the water column. It permits scientists to observe the physical properties in real-time via a conducting cable, which is typically connected to a CTD to a deck unit and computer on a ship. The CTD is often configured with additional optional sensors including fluorometers, transmissometers and/or radiometers. It is often combined with a Rosette of water sampling bottles (e.g. Niskin, GO-FLO) for collecting discrete water samples during the cast.
This term applies to profiling CTDs. For fixed CTDs, see https://www.bco-dmo.org/instrument/869934. |
| Dataset-specific Instrument Name | Hitachi fluorescence detectors (L-7485, L-2485, Chromaster - 5440) |
| Generic Instrument Name | Fluorometer |
| Dataset-specific Description | Hydrolysis of the substrates was measured as an increase in fluorescence as the fluorophore was hydrolyzed from the substrate over time [as in Hoppe, 1983; Obayashi and Suzuki, 2005]. |
| Generic Instrument Description | A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. The instrument is designed to measure the amount of stimulated electromagnetic radiation produced by pulses of electromagnetic radiation emitted into a water sample or in situ. |
| Dataset-specific Instrument Name | High-Performance Liquid Chromatograph |
| Generic Instrument Name | Gel Permeation Chromatograph |
| Dataset-specific Description | The hydrolysis of high molecular weight substrate to lower molecular weight hydrolysis products was measured using gel permeation chromatography with fluorescence detection, after the method of Arnosti [1996, 2003]. In short, the subsample was injected onto a series of columns consisting of a 21 cm column of G50 and a 19 cm column of G75 Sephadex gel. The fluorescence of the column effluent was measured at excitation and emission wavelengths of 490 and 530 nm, respectively.
Subsamples were run on a gel permeation chromatography instrument to separate out size classes of fluorescently-labeled polysaccharides. Hydrolysis is calculated as a change in the size distribution of polysaccharide with time. |
| Generic Instrument Description | Instruments that separate components in aqueous or organic solution based on molecular size generally for molecular weight determination. Gel permeation chromatography (GPC) is a type of size exclusion chromatography (SEC), that separates analytes on the basis of size. |
| Dataset-specific Instrument Name | Niskin bottle |
| Generic Instrument Name | Niskin bottle |
| Dataset-specific Description | Water was collected using a Niskin bottle and salinity values are from the CTD. |
| Generic Instrument Description | A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc. |
Collaborative Research: Pressure effects on microbially-catalyzed organic matter degradation in the deep ocean (Pressure effects on microbes)
NSF Award Abstract:
Microbes are important players in the carbon cycle in the ocean. These organisms consume organic carbon and produce carbon dioxide in marine systems. Because the average depth of the ocean is 4000 m, microbes must work at high pressures typical of the deep ocean (>1000 m). Although high pressure is known to affect marine microbes, their carbon cycling activities have mostly been measured at surface ocean pressures. As a result, it remains unknown how closely these measurements reflect the activities of deep-sea microbes at high pressures. As a result of collaborations with scientists in Denmark and Germany, this project will be able to use special equipment to investigate the effects of high pressures on marine microbes and their carbon cycling activities. This work is necessary to quantify rates of carbon cycling and identify the microbes involved, especially in deep waters. The project will provide training for diverse undergraduate and graduate students, and a postdoc who will conduct novel research in the U.S., Denmark, and Germany, both at sea and in the lab. The scientists will also teach middle school students about the role of microbes in the carbon cycle and pressure effects on life in the ocean. The project will provide internships for high school students, focusing on first-generation students who would like to go to college. This work may aid in future efforts to identify enzymes that function well under high pressure.
Heterotrophic microbes (e.g., bacteria and archaea) are found throughout the ocean. Their biogeochemical functions help determine the rates and locations at which carbon and nutrients are regenerated, as well as the extent to which organic matter is preserved. Although research has shown that pressure profoundly affects the activities of marine microbes, most investigations of microbial communities of the deep sea are conducted at atmospheric pressure, due to the limited availability of specialized equipment. In collaboration with the Danish Center for Hadal Research at the University of Southern Denmark, this study will identify the effects of pressure on microbial communities and their extracellular enzymes of pressures characteristic of bathy- and abyssopelagic depths. At sea and in the lab, the scientific team will compare the effects of depressurization on the activities of enzymes produced by microbial communities of the deep ocean, as well as the effects of high pressure on surface-water derived enzymes and communities. Fieldwork will take place in Danish coastal waters, well as in the open North Atlantic and Pacific Oceans. Using pressurization systems and in situ incubations, this study will measure hydrolysis rates of peptides and polysaccharides, two of the major classes of marine organic matter. Project activities will also focus on developing the means to measure enzyme activities in situ in the deep ocean. In collaboration with colleagues from the Max Planck Institute for Marine Microbiology in Germany, this proect will additionally investigate whether pressure affects the selfish uptake of polysaccharides. These studies will provide new insight into understudied but key factors that help determine the fate of organic matter in the deep ocean.
This project is funded by the Biological and Chemical Oceanography Programs.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) |
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