PBWS_2.doc

Phytoplankton Microscopic Identification and Enumeration Services

I. GENERAL INFORMATION

A. Introduction The U.S. Geological Survey (USGS) California Water Science Center (CAWSC) is requesting bids for microscopic identification and enumeration (tally, density, and biovolume) of phytoplankton species in surface water samples collected from the Sacramento San Joaquin River Delta.

B. Background The CAWSC is conducting multiple studies in the Sacramento San Joaquin River Delta. Samples will be collected through October 2025. We expect to collect up to 200 samples for analyses during the project period. Once collected, samples are preserved with Lugol’s iodine solution (2-5%) and stored in a cool, dark environment until analysis.

C. Definitions/Applicable Documents

· Lund, J.W.G., Kipling, C., & Le Cren, E.D. (1958). The inverted microscope method of estimating algal numbers and the statistical basis of estimations by counting. Hydrobiologia, 11, 143–170. https://doi.org/10.1007/BF00007865

· McNabb, C.D. (1960). Enumeration of Freshwater Phytoplankton Concentrated on the Membrane Filter. Limnology and Oceanography, 5(1), 57–61. https://doi.org/10.4319/lo.1960.5.1.0057

· American Public Health Association. (2012). Standard Methods for the Examination of Water and Wastewater, 22nd Edition. APHA, Washington, DC. ISBN 978-087553-013-0.

· Hillebrand, H., Durselen, C.D., Kirschtel, D., Pollingher, U., & Zohary, T. (1999). Biovolume calculation for pelagic and benthic microalgae. Journal of Phycology, 35, 403–424. https://doi.org/10.1046/j.1529-8817.1999.3520403.x

II. WORK REQUIREMENTS

A. Performance Objectives

· Phytoplankton will be enumerated using a compound microscope at magnifications ranging 100-1000X.

· Cells will be concentrated on a filter using a method similar to McNabb 1960 and Standard Methods 2012.

· At least 400 phytoplankton units or phytoplankton in up to 50 random fields will be enumerated to the lowest possible taxonomic level.

· An entire strip of the filter will be counted at approximately 630X, and half the filter counted at 400X for any organisms missed during random fields.

· Biovolumes will be estimated using the geometric shape method described in Hillebrand et al. 1999.

· Biovolumes per cell will be estimated on measurements from at least 10 cells per taxon for each sample.

· Chains-of-custody for all laboratory operations and analyses for each sample will be fully documented.

· Samples can be received by the Contractor Monday through Friday, and on Saturdays with advanced notification.

· Phytoplankton identification and enumeration will be conducted by expert analysts who have experience with phytoplankton identification.

· Sample results must be provided to USGS electronically within 12 weeks of sample receipt.

· At least annually, a master list of the taxonomic classification of all algal taxa identified in this project will be provided. The list will include the higher groupings used (e.g., superphylum, phylum, class) and the genus and species identities. Any taxonomic names that have changed in the last year will also be identified, showing the old and new names.

· At least annually, contractor will provide photographic documentation of taxon (species or genus) identification when first encountered. A taxon will be photographed only once. If the same taxon is encountered in subsequent samples, it does not need to be photographed. This includes all algal taxa and all non-algal protists. Do not photograph zooplankton. Each photograph should have a scale bar with the length given in micrometers. There may be more than one organism in the photograph if they are all the same taxon. For each unidentified organism, provide photographic documentation. For each photograph, note the type of microscope and camera, and the magnification at which it was taken. Images must be in digital format.

B. Performance Standards

· 100% of deliverables shall be submitted within 12 weeks of sample receipt.

· Enumeration shall meet minimum sample counts and random field counting requirements.

· All required fields shall be completed in data submissions.

· Photographs shall meet the documentation standards specified.

· 5% of samples must undergo split replicate QA analysis.

C. Deliverables Final deliverables for all work/products shall be completed and delivered no later than June 30, 2025 Deliverables shall include an Excel, CSV, or text file containing the following for each sample:

· Unique sample ID provided by USGS

· Analyst

· Station

· Sample date

· Sample time

· Sample aliquot (mL)

· Fields

· Genus

· Division

· Tally of natural units

· Tally

· Density (cells/mL)

· Average length

· Average width

· Average depth

· Cymbelloid

· Average measurements used to calculate the biovolume of gomphonemoid shaped organisms

· Average cymbelloid measurement used to calculate the biovolume for cymbelloid shaped organisms

· Biovolume (BV) factor

· Total BV (um3/mL)

· Lab comments

D. Performance Monitoring

· Contractor’s work will be monitored through periodic deliverable reviews for accuracy and completeness.

· Results from split replicate QA checks will be used to verify enumeration accuracy and consistency.

III. SUPPORTING INFORMATION

A. Place of Performance Location of Contractor’s facility.

B. Period of Performance May 19, 2025 – June 30, 2025.

C. Government Furnished Property (GFP) None.

D. Special Considerations Recent and long-term experience in the taxonomic identification and enumeration of phytoplankton species in the Sacramento San Joaquin River Delta and San Francisco Bay (Bay-Delta) is required.