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46 British Columbia (Canada) lakes

July 26, 2006   

Excerpts from:

Hall, R.I., and Smol, J.P. 1992. A weighted-averaging regression and calibration model for inferring total phosphorus concentrations from diatoms in British Columbia (Canada) lakes. Freshwater Biology. 27:417-434

Contents:

 Conclusions/Summary

 Kamloops Lake, an interesting application

 Study area and lake selection

 Data screening

 Diatom inference model

Conclusions/Summary

1. The relationship between surficial sediment diatom taxa (Bacillariophyceae) and measured limnological variables in 46 British Columbia lakes was explored using canonical correspondence analysis (CCA). Lake-water [TP] concentration, maximum lake depth, conductivity, and calcium concentration each accounted for independent and statistically significant directions of variation in the distribution of diatom taxa.

2. Weighted-averaging (WA) models were developed to infer lake-water TP from the relative abundances of 131 diatom taxa in the surficial sediments of 37 lakes. WA regression and calibration with classical deshrinking provided the best model for TP reconstructions.

3. The quantitative inference model has two major advantages over existing multiple linear-regression models:
   1. inferences were based on the responses of individual taxa to TP, and do not involve grouping the taxa into a small number of ecological categories; and
   2. the model assumes that diatoms respond to TP in a unimodal, rather than a linear, fashion.

4. The WA model can now be used to infer past lake-water TP, within the range 5-28 µg.l^-1, from diatoms preserved in the sediments of British Columbia lakes. The model can provide quantitative estimates of the onset, rate, and magnitude of lake eutrophication in response to natural processes and human disturbances.

Kamloops Lake, an interesting application of the model:

The model was applied to diatom assemblages preserved in a sediment core from Kamloops Lake, B.C. (a lake not included in the calibration set). The diatom inferred TP (8.7 µg.l^-1) from the surficial sediment sample closely agreed with the average TP (8.8 µg.l^-1) measured by the B.C. MOE. Although this preliminary result indicated the model may perform well, nonetheless it is a single sample with no statistical degrees of freedom and must be interpreted with caution.

Study area and lake selection

The topography, geology, climate, vegetation and soils of British Columbia are extremely heterogenous, and the lakes display a similarly broad range of physical, chemical, and biological characteristics. This study included 46 freshwater lakes (with well-preserved surficial sediment diatom assemblages) distributed predominantly in the southern half of the province. The lakes were specifically chosen to reflect a broad trophic gradient, and they spanned a wide range of TP (5-85 µg.l^-1). In order to minimize the influence of pH and pH-related variables on the distribution of diatom taxa, lakes were selected to include a relatively narrow pH range (7.5-8.5). The study area included four biogeoclimatic zones (Interior Douglas Fir, Coastal Douglas Fir, Interior Western Hemlock, and Cariboo Aspen-Lodgepole Pine). These zones are defined primarily in terms of temperature and precipitation, but also differ in vegetation and soil types.

Data screening:

The full 46 lake calibration set included a TP range of 5-85 µg.l^-1. The final CCA ordination was performed on 41 of these lakes and included a TP range of 5-28 µg.l^-1 because lakes with the highest TP were outliers. 5 lakes were identified as outliers and were removed from the ordination analyses. The other 4 lakes were removed from the final CCA analysis because they possessed extreme value(s) for the environmental variables (i.e., they had a value greater than 3 standard deviations from the mean). This resulted in 37 lakes for the final model.

Diatom inference model

Table: Total phosphorus optima and number of occurrences for the 131 diatom taxa included in the weighted-averaging model. Taxa with numbers followed by `BC' are taxa of unknown taxonomic position that were retained as distinct in this study. The taxa numbers in the first column are based on ascending TP optimum. In other words, No. 1 taxon has the lowest TP optimum (6.8 µgl^-1), whereas the No. 131 taxon has the highest TP optimum (23.3 µgl^-1)

No.	Diatom taxon	TP optimum (µgl-1)	Number of occurrences
47	Achnanthes biasolettiana Grun.	10.5	16
4	Achnanthes bioreti Germ.	7.3	3
73	Achnanthes clevei Grun.	11.7	17
23	Achnanthes conspicua A. Mayer	9.3	21
124	Achnanthes delicatula (Kütz.) Grun.	18.6	4
87	Achnanthes detha Hohn & Hellerman	12.2	14
97	Achnanthes exigua Grun.	12.7	24
96	Achnanthes exigua var. heterovalva Krasske	12.6	21
89	Achnanthes lanceolata (Bréb. ex Kütz.) Grun.	12.3	19
94	Achnanthes lanceolata var. dubia Grun.	12.6	18
110	Achnanthes lanceolata var. elliptica Cleve	14.3	15
2	Achnanthes levanderi Hust.	6.9	3
25	Achnanthes linearis (W. Smith) Grun.	9.3	14
14	Achnanthes microcephala (Kütz.) Cleve	8.8	9
20	Achnanthes minutissima Kütz.	9.0	27
49	Achnanthes pinnata Hust.	10.7	4
60	Achnanthes suchlandtii Hust.	11.2	7
59	Amphora libyca Ehrenb. ex Kütz.	11.2	23
12	Amphora parallelistriata Manguin	8.4	3
44	Amphora pediculus (Kütz.) Grun. ex A. Schmidt	10.4	32
31	Amphora thumensis (Mayer) Krieger	9.7	12
3	Anomoeoneis vitrea (Grun.) R. Ross	7.3	8
79	Asterionella formosa Hasall	11.8	25
74	Asterionella ralfsii W. Smith	11.7	4
120	Aulacoseira ambigua (Grun.) Simonsen	16.9	18
6	Aulacoseira distans (Ehrenb.) Simonsen	7.8	10
27	Aulacoseira distans var. nivalis (W. Smith) Kirchner	9.5	3
131	Aulacoseira granulata var. angustissima (O. Müll.) Simonsen	23.3	2
105	Aulacoseira italica ssp. subarctica (O. Müll.) Simonsen	13.2	13
53	Aulacoseira italica var. tenuissima (Grun.) Simonsen	11.0	11
15	Aulacoseira lirata (Ehrenb.) R. Ross	8.9	3
116	Aulacoseira lirata var. lacustris (Grun.) R. Ross	15.8	6
26	Aulacoseira perglabra var. floriniae Camburn	9.3	4
107	Aulacoseira undulata (Ehrenb.) Kütz.	13.7	4
1	Aulacoseira sp. 12 PIRLA	6.8	2
69	Cocconeis diminuta Pant.	11.6	21
100	Cocconeis placentula Ehrenb.	12.9	8
109	Cocconeis placentula var. euglypta (Ehrenb.) Grun.	14.0	8
85	Cocconeis placentula var. lineata (Ehrenb.) Van Heurck	12.1	10
122	Cyclostephanos sp. 1 BC	17.5	3
75	Cyclotella bodanica Grun.	11.7	26
42	Cyclotella bodanica var. affinis Grun.	10.2	16
61	Cyclotella cf. radiosa (Grun.) Lemm.	11.3	3
5	Cyclotella comensis Grun.	7.4	7
106	Cyclotella kuetzingiana Thwaites	13.6	11
8	Cyclotella kuetzingiana var. planetophora Fricke	7.9	2
10	Cyclotella kuetzingiana var. radiosa Fricke	8.3	5
16	Cyclotella meneghiniana Kütz.	9.0	2
35	Cyclotella michiganiana Skvortzow	10.1	19
111	Cyclotella ocellata Pant.	14.5	8
32	Cyclotella stelligera (Cleve & Grun.) Van Heurck	9.7	24
18	Cymbella cesatii (Rabenh.) Grun.	9.0	2
11	Cymbella delicatula Kütz.	8.3	7
24	Cymbella diluviana (Krasske) M.B. Florin	9.3	7
71	Cymbella microcephala Grun.	11.6	16
38	Cymbella minuta Hilse ex Rabenh.	10.2	14
98	Denticula elegans Kütz.	12.7	6
21	Diatoma hiemale var. mesodon (Ehrenb.) Grun.	9.2	5
54	Diatoma tenue var. elongatum Lyngb.	11.0	7
117	Epithemia argus (Ehrenb.) Kütz.	16.4	9
36	Fragilaria brevistriata Grun.	10.1	36
104	Fragilaria brevistriata var. capitata Hérib	13.2	6
91	Fragilaria brevistriata var. elliptica Hérib	12.3	15
40	Fragilaria brevistriata var. inflata (Pant.) Hust.	10.2	22
86	Fragilaria capucina var. mesolepta (Rabenh.) Rabenh.	12.2	9
119	Fragilaria construens (Ehrenb.) Grun.	16.6	28
88	Fragilaria construens var. binodis (Ehrenb.) Grun.	12.3	12
82	Fragilaria construens var. venter (Ehrenb.) Grun.	12.0	34
108	Fragilaria crotonensis Kitton	13.9	21
78	Fragilaria lapponica Grun.	11.8	28
113	Fragilaria pinnata Ehrenb.	15.0	36
65	Fragilaria pinnata var. intercedens (Grun.) Hust.	11.4	21
84	Fragilaria pinnata var. lancettula (Schum.) Hust.	12.1	28
63	Fragilaria vaucheriae (Kütz.) J.B. Petersen	11.4	8
7	Fragilaria virescens var. exigua Grun.	7.8	2
58	Fragilaria sp. 1 BC	11.2	16
46	Fragilaria sp. 2 PIRLA	10.4	14
29	Fragilaria sp. 3 PIRLA	9.5	3
33	Fragilaria sp. 4 PIRLA	9.9	7
57	Gomphonema angustatum (Kütz.) Rabenh.	11.1	6
13	Gomphonema angustum Agardh.	8.6	4
39	Gomphonema parvulum (Kütz.) Kütz.	10.2	4
129	Gomphonema subtile Ehrenb.	21.5	3
127	Gyrosigma acuminatum (Kütz.) Rabenh.	20.6	3
34	Mastogloia smithii Thwaites ex W. Smith	10.0	6
115	Navicula absoluta Hust.	15.2	11
99	Navicula cari Ehrenb.	12.8	13
51	Navicula cryptocephala Kütz.	10.8	12
48	Navicula explanata Hust.	10.5	2
41	Navicula laevissima Kütz.	10.2	12
52	Navicula minima Grun.	10.9	17
102	Navicula pseudoventralis Hust.	12.9	16
83	Navicula pupula Kütz.	12.1	17
43	Navicula radiosa Kütz.	10.3	9
121	Navicula scutelloides W. Smith ex Greg.	17.3	8
95	Navicula seminuloides Hust.	12.6	16
77	Navicula shadei Krasske	11.8	6
45	Navicula subminiscula Manguin	10.4	13
92	Navicula submuralis Hust.	12.5	15
22	Navicula utermoehlii Hust.	9.2	6
125	Navicula ventralis Krasske	18.7	4
80	Navicula vitabunda Hust.	11.8	19
9	Neidium ampliatum (Ehrenb.) Krammer	8.0	1
76	Nitzschia denticula Grun.	11.7	13
67	Nitzschia fonticola Grun.	11.5	21
130	Pinnularia braunii (Grun.) Cleve	21.6	2
126	Pinnularia nodosa (Ehrenb.) W. Smith	20.6	3
55	Rhopalodia gibba (Ehrenb.) O. Müll.	11.0	5
128	Stauroneis anceps Ehrenb.	21.0	6
30	Stauroneis phoenicenteron (Nitzsch) Ehrenb.	9.6	6
62	Stephanodiscus alpinus Hust.	11.3	13
68	Stephanodiscus cf. vestibulis Håkansson, Theriot, & Stoermer	11.6	2
118	Stephanodiscus cf. pseudoexcentricus Håkansson & Stoermer	16.5	3
93	Stephanodiscus hantzschii Grun.	12.5	13
101	Stephanodiscus hantzschii fo. tenuis (Hust.) Håkansson & Stoermer	12.9	5
56	Stephanodiscus medius Håkansson	11.0	10
90	Stephanodiscus minutulus (Kütz.) Cleve & Möller	12.3	24
112	Stephanodiscus niagare Ehrenb.	15.0	14
66	Stephanodiscus parvus Stoermer & Håkansson	11.4	12
103	Stephanodiscus sp. 1 BC	13.0	1
19	Stephanodiscus sp. No. 5 BC	9.0	2
72	Synedra cyclopum Brutscy	11.7	11
64	Synedra delicatissima Grun.	11.4	3
70	Synedra filiformis var. exilis Cleve-Euler	11.6	5
81	Synedra minuscula Grun.	12.0	1
37	Synedra parasitica (W. Smith) Hust.	10.1	15
17	Synedra radians Kütz.	9.0	2
50	Synedra ulna var. chaseana Thomas	10.8	4
28	Tabellaria fenestrata (Lyngb.) Kütz.	9.5	2
123	Tabellaria flocculosa str. III sensu Koppen	17.6	7
114	Tabellaria flocculosa str. IIIp sensu Koppen	15.1	7

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