Ensuring quality diatom taxonomic identifications and developing diatom-based metrics for diagnosing nutrient impairment in Kentucky

Lara PanayotoffKentucky Division of Water

Does it matter?

• Genus Level resolution?

• Isn’t internal consistency enough?• All this “splitting” is messing with my head! Why are

taxonomists doing this to me?• My historical dataset is worth what now?

• It’s doable, it’s getting easier• Regional and national comparability provides more

complete context for local information• It expands the usefulness of our data beyond our borders

Diatoms of the US: Kickin’ it old school

• despite 800+ taxa represented, quite incomplete

• line drawings often hard to interpret

• many taxa represented by just one drawing

Sprechen sie Deutsch?

Regional floras, monographs, and journal articles

National Programs – comparability, consistency?

• North American Diatom Ecological Database (NADED) - ANSP

• Image databases• Program-focused

taxonomy workshops• Slides deposited in

publically accessible herbarium

• Numerous publications of new taxa or treatment of problem groups

NAWQA

• formal editorial review

• high quality information

• dynamic• relative few

species at this time (207) but expanding quickly

New Web Resource for Diatom Identification

Spaulding, S.A., Lubinski, D.J. and Potapova, M. (2010). Diatoms of the United States. http://westerndiatoms.colorado.edu Accessed on 07 November, 2011.

Diatoms of the United States

Diatoms of the US: way informative species pages

• many images representing size range

• original species description and images

• comparison with similar taxa

• autecological information

• species occurrence maps from EMAP

• reviewed taxa list, identification notes, and slides• nomenclature changes (e.g., genus transfers)• newly clarified concepts• taxa likely to be present but not reported• possible misidentifications• compare with NADED list and taxonomic concepts

• some issues:• many cases of simple nomenclature differences• Achnanthidium deflexum• Gomphonema angustatum• “Achnanthes lanceolata” complex• Nitzschia, many groups• small Navicula• many unreported taxa

KDOW’s 2008 Diatom taxonomy update project

• original list 678 names - 319 taxon names added• 193 names “deactived” – historical data left

unchanged but these names no longer accepted for new analyses

• added new fields to taxa table:• reference description citation• reference figures citation• Authority• is_active• combine_to_name• NADED_ID

• 87 names added since – currently 841 active names• 73 do not have NADED IDs: 42 legit names, 31

“unknowns”

KDOW’s 2008 Diatom taxonomy update project

Diatom Digital Image Library

• Spot Insight 4MP digital camera

• SPOT software associates notes, measurements, scale bars with images – can burn to image or not

• standardized filenames hold the taxon code and the sample ID; stamped onto image

• over 1000 images representing hundreds of taxa, filed in genus folders

• hope to create database for easier searching and viewing; using Windows search for now

• database also will help track verification status and notes

Diatom Digital Image Library

2011 Diatom QA project

• FY09 106 supplemental grant funds (in part)• MOA with Academy of Natural Sciences, Diatom

Herbarium Curator Marina Potapova• Focus on 2008-10 nutrient studies in

Pennyroyal and Mountains regions

2011 Diatom QA project

• Objectives:• Verification of 300+ voucher images representing 150

taxa – all “common” or “frequent” taxa (>1% in any sample)

• Verification or guidance for 2 taxonomic problem areas

• “Achnanthidium deflexum complex”• “Gomphonema angustatum complex”

• Recommendations for several “unknowns” or uncertain identifications

Differences in splittingCocconeis placentula var. lineata vs. euglyptaNavicula minima vs. Sellaphora seminulum

Differences in nomenclatureAchanthes nollii is Achnanthidium latecephalumGomphonema pumilum is G. kobayasii

Downright wrongNavicula absoluta, really N. ruttneri var. capitataDiplonies boldtiana, really D. puellaNitzschia supralitorea, really N. liebetruthii

2011 Diatom QA project: Image Verification

Voucher image verifications: 305 of 368 confirmed ok

Voucher image verifications: 305 of 368 confirmed ok

2011 Diatom QA project: Image Verification

“Chamaepinnularia evanida” “Encyonema hebridicum”“Achnanthes pinnata”

Encyonema sp. 1 MONTANA HAMSHERNavicula sp. 5 ANS NEW JERSEY KCPundescribed Platessa

2011 Diatom QA project : Achnanthidium

A. deflexum

A. latecephalum(“A. nollii”)

A. rivulare

A. druartii( A. sp. 3 KDOW LAP)

A. gracillumum

A. sp. 1 KYDOW LAP

(Achnanthidium sp. 3 cf. alteragracillima

KYDOW LAP)

Spaulding, S.A., Lubinski, D.J. and Potapova, M. (2010). Diatoms of the United States. http://westerndiatoms.colorado.edu Accessed on 07 November, 2011.

2011 Diatom QA project : Achnanthidium

Achnanthidium sp. 1 KYDOW LAP.Photo by Marina Potapova

Scale bars = 1 micron

2011 Diatom QA project: Achnanthidium

undescribed Achnanthidium

“Gomphonema angustatum complex”

2011 Diatom QA project: Gomphonema

G. micropus

G. cymbelliclinumG. drutiligense G. innocens

G. sp. 8 cf. sarcophagus KYDOW LAP

2011 Diatom QA project: Unknowns

Navicula sp. 1 KYDOW LAP

Navicula sp. 2 KYDOW LAP

Nitzschia sp. 2 KYDOW LAP

Planothidium sp. 1 KYDOW LAP

Sellaphora sp. 1 KYDOW LAP

Sellaphora sp. 2 KYDOW LAP

10µm

6 unknowns judged to be “probably undescribed species”

2011 Diatom QA project: Unknowns

Navicula dibola HohnPhotos by Marina Potapova

holotype

Hohn, M.H. 1961. The Relationship Between Species Diversity and Population Density in Diatom Populations from Silver Springs, Florida. Trans. Amer. Micro. Soc. 80(2):140-165.

QC analyses on 19 slides: 1000 valve count, separate “strips”

Discrepancies- many of the same issues from voucher images, plus several more

• Achnanthidium eutrophilum / A. minutissimum• Cymbella turgidula / C. subturgidula / C. tropica• Encyonema silesiacum / E. neogracile• Remeria sinuata / uniseriata• Navicula absoluta / N. ruttneri var. capitata

Percent Similarity:

Initial: range from 49 – 89%After resolving identification discrepancies: 76-91%

2011 Diatom QA project: QC Analyses

s

ic ii baPS

1),min( where: ai = percentage of species i i count A

bi = percentage of species i in count B

2011 Diatom QA project outcomes

• verified images can be used as reference in the future

• improved confidence in comparability• many unknowns confirmed to still be unknown• problems to look out for• contributed to understanding of rarely reported

taxa, slides accessioned at ANSP accessible to researchers

• better idea of range of recount % similarity to expect

• QC recounts, voucher verifications, and special problems work gave different and complementary information

So where does that get us?

http://pubs.usgs.gov/ds/ds329/

• % Eutrophic diatom individuals or taxa

• Trophic Index• % Hi TP/TN and Low TP/TN

indicating individuals or taxa

• Oxygen Tolerance Index• Saprobity Index

Thanks! Questions?