QUALITY ASSURANCE/QUALITY CONTROL Maryland Department of Natural Resources followed specific procedures to ensure that the Mainstem component of the Chesapeake Bay Water Quality Monitoring Program design was properly implemented and managed with sufficient accuracy, precision and detection limits. Accuracy (closeness to the true value) of collected data was controlled and assured by proper use, calibration and maintenance of both field and laboratory equipment for the measurement of physical and chemical parameters. The procedures to control and assure the accuracy of field measurements involved the calibration of field instruments, the verification of calibrations, and equipment maintenance. Most of the details of how data acquired with YSI sondes were quality assured and quality controlled are described in the process description elements in the Lineage portion of this metadata record.
Daily quality control checks, which included the running of blanks and standards, were used to control and assure laboratory accuracy. Accuracy of Chesapeake Biological Laboratory, Nutrient Analytical Services Laboratory (CBL NASL) results was also assessed through DNR's participation in the Chesapeake Bay Coordinated Split Sample Program (CSSP) a split sampling program in which five laboratories involved in Chesapeake Bay monitoring analyze the coordinated split samples. CSSP was established in June 1989 to establish a measure of comparability between sampling and analytical operations for water quality monitoring throughout the Chesapeake Bay and its tributaries. DNR followed the protocols in the Chesapeake Bay Coordinated Split Sample Program Implementation Guidelines (EPA 1991) and its revisions. Split samples were collected quarterly. Results were analyzed by appropriate statistical methods to determine if results differed significantly among labs. If a difference occurred, discussions began regarding techniques and potential methods changes to resolve discrepancies.
ADDITIONAL COMMENTS
January 2020: Scoping is a term used to describe situations when strong currents and or winds make it difficult to maintain the water quality data sonde at a depth long enough for readings to stabilize. Meter scoping was noted at stations CB2.2, CB3.1, CB4.4, and CB5.1. Phytoplankton samples collected at stations CB4.4, CB5.1, CB5.1W, CB5.2, LE2.3, CB5.3, CB4.3C, CB4.1C, CB3.3C, CB4.2C, CB2.1, CB2.2, CB3.1, and CB3.2. Sampling was conducted in the fog at stations CB3.1 and CB3.2.
February 2020: Meter scoping was noted at station CB5.3. Phytoplankton samples collected at stations CB5.2, LE2.3, CB3.3C, CB4.3C, and CB3.1. Sampling was conducted in the fog at stations CB3.3C, CB4.1C, CB4.2C, and CB4.3C. Station CB5.1W was sampled after an earlier rainstorm. There was no pycnocline at station CB2.2 and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. Conductivity readings at 0.5 m depth was very unstable at station CB3.2. Surface and above pycnocline water samples collected at station CB3.2 were taken from the same bottle.
May 2020: The May mainstem survey was conducted May 26-June 2. Phytoplankton samples were collected at stations CB3.3C, CB1.1, CB3.3E, CB3.3W, CB3.2, CB4.3E, CB4.3C, CB4.3W, CB4.2W, CB4.2E, CB4.2C, CB4.1E, CB4.1C, CB4.4, CB5.3, CB5.1, CB5.2, and LE2.3. Sampling was conducted in the fog at stations CB3.2, CB4.3E, and CB4.3C. Conductivity readings at 10 m depth were unstable at station CB5.2. The sonde/bottle sampling array touched bottom at 8 m at station CB2.1. Surface and above pycnocline water samples collected at station CB4.2C were taken from the same bottle. The sonde/bottle sampling array touched bottom at 8 m at station CB4.2E. The 5 m water quality sonde readings at station CB3.1 were double-checked. Stations CB4.4 and CB5.1 surface and 1 m sonde measurements were made at the same depth due to rough seas.
June 2020: The first June mainstem survey was conducted June 8-12. Phytoplankton samples were collected at stations CB3.3C, CB1.1, CB3.3E, CB3.3W, CB4.3E, CB4.3C, CB4.3W, CB4.2W, CB4.2E, CB4.2C, CB4.1E, CB4.1C, CB4.1W, CB4.4, CB5.3, CB5.1, CB5.2, and LE2.3. The 11 m water quality sonde readings at station CB5.2 were double checked. There was no pycnocline at station CB2.2 and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. The 3 m and 4 m temperature readings at station CB3.3W were double checked. An odor of H2S was observed in bottom and below pycnocline water samples collected at stations CB3.3C and CB4.1E. An odor of H2S was also observed in below pycnocline samples collected at stations CB4.1C and CB4.2C
The second June survey was conducted June 24-26. Phytoplankton samples were collected at stations CB4.4, CB4.1E, CB4.3C, CB4.3E, CB3.3E, CB4.1C, CB4.1W, CB4.3W, CB3.3C, CB3.1, CB3.2, and CB3.3W. Samples to analyze for vibrio were collected at stations CB5.2, CB5.3, CB4.3C, and CB2.2. An odor of H2S was observed in bottom and below pycnocline water samples collected at station CB4.1C. There was no pycnocline at station CB2.2 and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth. Bottom and below pycnocline water samples collected at stations CB3.1 and CB3.2 were taken from the same bottle.
July 2020: The first July mainstem survey was conducted July 6-8. Phytoplankton samples were collected at stations CB5.2, CB4.3C, CB3.3C, CB2.2, and CB1.1. Samples to analyze for Vibrio were collected at stations CB5.2, CB4.3C, CB3.3C, CB2.2, and CB1.1. Conductivity readings at 9 m depth were unstable at station CB5.2. Station CB5.1 surface and 1 m sonde measurements were made at the same depth. The sonde/bottle sampling array touched bottom at 11 m at station CB3.2. The 4 m and 5 m dissolved oxygen readings at station CB3.2 were double checked. There was no pycnocline at station CB2.2 and above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of station total water column depth.
The second July mainstem survey was conducted July 20-22. Water column measurements only (no pigment or nutrient samples) were collected during the second July mainstem survey, except at station CB3.3E where a phytoplankton sample was collected. It was noted that thunderstorms had occurred the evening prior to surveys at stations CB4.1W, CB3.2, CB3.1, and CB2.2.
August 2020: The first August mainstem cruise was conducted August 3-11. Phytoplankton samples collected at stations CB5.2, CB4.3C, CB4.3W, CB4.2W, CB3.3C, CB3.3W, CB2.2, and CB1.1. Stations CB5.2, CB5.1, CB4.4, CB4.1C, CB3.3C, CB4.3E, CB4.3C, CB4.2C, and CB4.1E samples from the bottom and below pycnocline waters had hydrogen sulfide odors. An early morning thunderstorm was noted at station CB5.1. Surface samples were taken at stations CB1.1, CB2.2, CB3.3C, CB4.3C, and CB5.2 for Oxford Cooperative laboratory to test for Vibrio. Water temperature was double checked at the 3m sampling depth at station CB4.2E, and the DO reading at 1m depth at station CB5.1W was also double checked. Station CB4.4 surface (0.5 m) and 1.0 m water column results were acquired at a single depth due to rough seas. The pH 10 post calibration result of the sonde was outside of the acceptable limit. An odor of H2S was observed in bottom and below pycnocline samples collected at stations CB5.2, CB5.1, CB4.4, CB4.3E, CB4.3C, CB4.2C, CB4.1E, CB4.1C, and CB3.3C.
The second August mainstem survey was conducted August 25-26, and hazy conditions were reported during this cruise. Phytoplankton samples collected at stations CB3.3E, CB3.3C, and CB4.3C. A pycnocline was not evident at stations CB4.1E, CB3.1, or CB2.2, therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. The above pycnocline sample for station CB4.1C was taken at 14m, and should have been taken at 12m. Bottom and below pycnocline samples were collected from a single bottle at station CB3.2.
September 2020: Due to technical issues, a YSI EXO was used as well as a YSI 6600 on the September sampling survey. The majority of the readings were taken with a YSI EXO, and compared with YSI 6600 readings, when available. The water quality meter was scoping towards the bottom at station CB5.3. Phytoplankton samples were collected at station CB5.2, CB4.3C, CB3.3E, CB3.3C, CB2.2, and CB1.1. Pycnoclines were not evident at stations: LE2.3, CB5.1, CB5.2, and CB4.1E. At stations LE2.3, CB5.1, and CB4.1E the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. The dissolved oxygen readings at 21m at station CB4.3E were double-checked. Bottom and below pycnocline samples were collected from a single bottle at station CB4.2C.
October 2020: A pycnocline was not evident at stations CB3.2 and CB3.3C, therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. No pycnocline was detected at CB3.2. At stations LE2.3, CB5.1, and CB5.2, the surface and 1m sonde readings were taken at the same depth. The bottom could not be reached at CB5.1. Notes state that, while sampling station CB3.3W, the water was very cloudy and stirred up and that a cargo ship had just passed. Phytoplankton samples were collected at stations CB5.1, CB5.2, CB4.3C, CB3.3C, CB3.2, CB1.1, and CB2.2.
November 2020: Due to technical issues, a YSI EXO was used on the November sampling survey. Pycnoclines were not evident at stations: CB4.4, CB5.1, CB5.2, LE2.3, CB5.3, CB4.3C, CB3.3C, CB4.1C, CB4.2C, CB3.2, CB1.1, CB2.1, CB3.1, and CB2.2. Therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. No pycnocline was calculated at station CB3.3C. Surface readings changed between the beginning and end of the hydrocasts at stations CB5.3. The post calibration check of the EXO pH meter read 0.2 units higher than the standard at stations CB1.1, CB2.1, CB2.2, CB3.1, and CB3.2. Phytoplankton samples were collected at stations CB5.1, CB5.2, CB4.3C, CB3.3C, CB3.2, CB1.1, and CB2.2.
December 2020: Due to technical issues, a YSI EXO was used on the December sampling survey. Pycnoclines were not evident at stations: CB4.4, CB4.3C, CB5.1, CB5.2, and LE2.3. Therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. No pycnocline was detected at stations CB4.2C, CB3.3C, or CB4.1C. At station CB3.3C the surface and 1m sonde readings were taken at the same depth. Wind gusted to 36kt while station CB4.1C was sampled. Surface conductivity readings changed between the beginning and end of the hydrocasts at stations CB3.1 and CB3.2. The pH sensor was slow to respond during sampling at station CB1.1, values were recorded once the readings were stable. Dense fog was reported in the morning at station CB5.1W.