1. Algal metric approaches for assessing trophic condition and organic enrichment in U.S. streams and rivers Stephen D. Porter Norman E. Spahr David K. Mueller Mark D. Munn Neil M. Dubrovsky NWQMC Meeting May 10, 2006 San Jose, CA

2. EPA National Water Quality Inventory (305b Report to Congress)  Causes of water-quality impairment Siltation Siltation Nutrients Nutrients Oxygen-depleting substances Oxygen-depleting substances  Sources of water-quality impairment Nonpoint-source runoff from urban & agricultural land Nonpoint-source runoff from urban & agricultural land EPA Nutrient Criteria – Streams and Rivers (U.S. EPA, 2000)  Primary Variables Nutrients (TN & TP) Nutrients (TN & TP) Algal Biomass (chlorophyll a) Algal Biomass (chlorophyll a) Water Clarity (turbidity, transparency, total suspended solids) Water Clarity (turbidity, transparency, total suspended solids)  Secondary Response Variables Stream Metabolism—DO, pH Stream Metabolism—DO, pH Biological Attributes (autecology, nature of response, grazers, IBIs) Biological Attributes (autecology, nature of response, grazers, IBIs) Why are algae important for assessing water quality?

3. Objectives and Scope 1. 1.Which algal metrics are most useful for assessing nutrient and organic enrichment in streams and rivers? 2. 2.How well do these metrics correlate with nutrient concentrations Nationally? Regionally? 3. 3.Do the algal metrics discriminate among land-use categories? 4. 4.How do algal metric scores respond along nutrient and land-use gradients? 5. 5.Does algal biovolume (biomass, chlorophyll) vary significantly with nutrient concentrations, land-use conditions, or among major water- resource regions? Do algal metrics and nutrient concentrations provide complementary information about the effects of land-use practices on water quality? How do trophic boundaries derived from USGS biovolume data compare with proposed nutrient criteria? How do trophic boundaries derived from USGS biovolume data compare with proposed nutrient criteria?

4. Nutrients Nitrogen: N-fixing algae, N-heterotrophs Nitrogen: N-fixing algae, N-heterotrophs N & P: eutrophic diatoms and soft (non-diatom) algae N & P: eutrophic diatoms and soft (non-diatom) algae Organic Enrichment Pollution Tolerance (saprobien system; nutrients+carbon) Pollution Tolerance (saprobien system; nutrients+carbon) Dissolved oxygen requirements; tolerance to low DO Dissolved oxygen requirements; tolerance to low DO Major Ions Salinity (specific conductance); alkalinity (hardness); certain metals Salinity (specific conductance); alkalinity (hardness); certain metals Phy sical Properties (pH, temperature, velocity, light, etc.) Indicators of algal biomass Chlorophyll a, Ash-free Dry Mass, Biovolume Chlorophyll a, Ash-free Dry Mass, Biovolume Indicators of water quality and trophic condition Qualitative – published literature accounts (~ 100 y history) Qualitative – published literature accounts (~ 100 y history) Algal Metrics... aggregation of species with similar autecological properties Autecology… physiological requirements or tolerance range of species

5. Periphyton collection methods

6. -0.50.00.51.0 PCA (1) -0.5 0.0 0.5 1.0 NF_YS SL_HB ON_NH TR_E PC_MT OT_AH -0.50.00.51.0 PCA (1) -0.5 0.0 0.5 1.0 PCA (2) NF_YS ES_SF SL_FR TR_O SP_OL ON_AL SP_PS OT_VL OT_AH PT_LB TR_M PT_TB PT_VT PC_MT TR_E SL_FB PC_LT ON_AH OT_MD EUTROPHIC SP_AM ON_NH SP_BM PC_SN OT_FH SL_HB PT_LA OT_LW SP_AP Which algal metrics are most useful for assessment? PC_MT Tolerant Diatoms—Indicator of nutrient & organic enrichment ON_NH Nitrogen Heterotrophs—Indicator of organic nitrogen enrichment TR_E Eutrophic Diatoms—Indicator of nutrient enrichment SL_HB Halobiontic Diatoms—Indicator of dissolved constituents NF_YS Nitrogen Fixers—Indicator of low nitrogen or N:P ratios OT_AH High DO Indicators—Indicator of high dissolved oxygen concentrations

7. Geographic regions based on aggregations of Water-Resource Regions

8. How well do “tolerant” algal metrics correlate with nutrients? Total Nitrogen Total Phosphorus

9. 912 923 TN TP 180 182 121 120 248 249 60 70 81 80 79 103 40 Nitrogen Fixers Nat Region -0.5 -0.3 -0.1 0.1 0.3 0.5 12345678 Nat Region -0.5 -0.3 -0.1 0.1 0.3 0.5 12345678 180 182 912 923 121 120 248 249 60 70 81 80 103 40 79 TN TP High DO Indicators Nat Region -0.5 -0.3 -0.1 0.1 0.3 0.5 12345678 Nat Region -0.5 -0.3 -0.1 0.1 0.3 0.5 12345678 Nitrogen Fixers NitrateOrthophosphate How well do “sensitive” algal metrics correlate with nutrients? Total Nitrogen Total Phosphorus Spearman Correlation Coefficient

10. What do algal metrics tell us about land use? Undev Partial Ag Urban Mixed Large Land Cover 0 20 40 60 80 100 ON_NH (relative abundance) cba aaa Undev Partial Ag Urban Mixed Large Land Cover 0 20 40 60 80 100 TR_E (relative abundance) c a abababab a a b Undev Partial Ag Urban Mixed Large Land Cover 0 20 40 60 80 100 SL_HB (relative abundance) d c abababab bcbcbcbcaa Undev Partial Ag Urban Mixed Large Land Cover 0 20 40 60 80 100 PC_MT (relative abundance) d c abababab a abababab bcbcbcbc Nitrogen Heterotrophs Tolerant Diatoms Halobiontic Diatoms Eutrophic Diatoms

11. What do nutrient concentrations tell us about land use? Undev Partial Ag Urban Mixed Large Land Cover 0 5 10 15 20 Total Nitrogen (mg/L) cb aa a a Undev Partial Ag Urban Mixed Large Land Cover 0 5 10 15 Nitrite + Nitrate Nitrogen (mg/L) c b a aab Undev Partial Ag Urban Mixed Large Land Cover 0 1 2 3 Total Phosphorus (mg/L) dc abababab abababab a bcbcbcbc Undev Partial Ag Urban Mixed Large Land Cover 0.0 0.5 1.0 1.5 2.0 Orthophosphate (mg/L) d c abababab ababababa bcbcbcbc Total Nitrogen Total Phosphorus Nitrite + Nitrate Orthophosphate

12. Algae = Nutrients Nutrients better than Algae Neither Algae nor Nutrients How well do algal metrics & nutrients discriminate between undeveloped and developed stream basins?

13. 03691215 Total Nitrogen (mg/L) 0 20 40 60 80 100 Percentage of eutrophic diatoms 012345 Orthophosphate (mg/L) 0 20 40 60 80 100 Percentage of eutrophic diatoms 03691215 Nitrite + Nitrate Nitrogen (mg/L) 0 20 40 60 80 100 Percentage of eutrophic diatoms 012345 Total Phosphorus (mg/L) 0 20 40 60 80 100 Percentage of eutrophic diatoms How do algal-metric scores respond along nutrient gradients? RMSE = 18.7 (94%) n = 912 RMSE = 19.1 (97%) n = 973 RMSE = 19.0 (96%) n = 922 RMSE = 19.2 (98%) n = 973 Percentage of eutrophic diatoms

14. 020406080100 Percentage of urban land (ag < 25%) 0 20 40 60 80 100 Percentage of eutrophic diatoms 020406080100 Percentage agricultural land (urban < 5%) 0 20 40 60 80 100 Percentage of eutrophic diatoms RMSE = 16.7 (100%) n = 634 RMSE = 18.7 (118%) n = 505 How do algal-metric scores respond along land-use gradients?

15. Algal biovolume relations with geographic region, water quality, and land use Median National: ( positive relation) Nitrate (  = 0.179, p<0.001) (negative relation) Suspended Sediment (  = -0.168, p=0.001) (negative relation) Suspended Sediment (  = -0.168, p=0.001) Regions 4, 7, & 8: (positive relation) TN, Nitrate, TP (  > 0.3) Region 5: (negative relation) Suspended Sediment, TP (  < -0.4)

16. 12345678 Region 0.0001 0.001 0.01 0.1 1 10 100 1000 Biovolume (cm 3 /m 2 ) Ag Large Mixed Partial Undev Urban Land Use EutrophicMesotrophicOligotrophic Estimating trophic boundary conditions Oligotrophic-Mesotrophic 1.352120 Mesotrophic-Eutrophic 156670 Biovolume (cm 3 /m 2 ) est. CHLa (mg/m 2 ) Dodds et al. (1998) benthic CHLa (mg/m 2 )

17. < 1.35 1.35 – 5.67 5.68 – 15 > 15.01 Distribution of algal biovolume, cm 3 /m 2

18. Distribution of eutrophic diatoms Eutrophic Diatoms, percent

19. Distribution of nitrogen-fixing algae Nitrogen Fixers, percent

20. Summary & Conclusions 1. What do algal metrics tell us about water quality? 2. What does algal biovolume tell us about water quality? Strong correlation with nutrient concentrations Discrimination between developed & undeveloped basins Responses along nutrient and land-use gradients Weak correlation with nutrient and sediment concentrations No significant differences among land-use or regional categories Algal biomass may be controlled more by antecedent hydrologic disturbance, shading, or biological interactions (e.g. grazers) than land-use practices or nutrient concentrations. Local scale response. Distribution of algal tolerance indicators corresponds with major agricultural and urban areas.

21. 3. How can algal indicators of stream condition be applied to nutrient and biological criteria? Summary & Conclusions Autecological metrics reflect responses to eutrophication processes Biovolume (standing crop)—hydrology relations (days of accrual) Indicators of organic enrichment Algal data available from NAWQA Data Warehouse Taxonomic consistency: ANSP http://diatom.acnatsci.org/nawqa/ http://diatom.acnatsci.org/nawqa/ Autecology: NAWQA Algal Attributes table Data Analysis: Algal Data Analysis System (ADAS—T.F. Cuffney) PhycoAide (ANSP) PhycoAide (ANSP)

22. Stephen D. Porter USGS—Water Resources NAWQA National Synthesis Box 25046, MS406, DFC Denver, CO 80225 sdporter@usgs.gov303-445-4647 Literature Cited Dodds, W.K., Jones, J.R., and Welch, E.B., 1998, Suggested classification of stream trophic state: Distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Resources, v. 32, no. 5, p. 1455-1462. U.S. Environmental Protection Agency, 2000, Nutrient criteria technical guidance manual. Rivers and Streams. Washington, D.C.: U.S. Environmental Protection Agency, Office of Water, EPA-822-B-00-002, 240 p.