The Diatom Flora of Bethany Bog

RUTH PATRICK Academy of Xatural Sciences o f Philadelphia, Philaddphia, Pa.

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SUMMARY. The results of these studies indicate that the first diatom flora developed a t the 13- meter level. The flora a t 12 meters increased. At the 11- and 9-meter levels the lake became increas- ingly eutrophic. Both plankton and benthic forms were present. At the 8- and 7-meter levels the lake was in a transitional stage from lake lo bog conditions. From 6 meters to the surface bog conditions were present

ETHANY BOG is located northwest of New Haven, Connecticut, in the Western Highland a t

an elevation of 600 feet. Deevey(1) published a paper concerning the pollen profile of this bog. He stated that the original lake had been reduced by a floating mat to a pool about three yards in diameter. His boring was made near the center, and the fine section, which was 13.9 meters long, indicated that the mat was no longer floating a t this point but anchored on sediments.

Recently Vallentyne (4) has studied the pigments which could be extracted from the sediments in the bog: the loss on ignition of organic matter: and the nitrogen, determined by the Kjeldahl method. which was present a t various levels. He has shown that there are significant changes in the amounts of pigments and nitrogen present a t certain levels. The purpose of this paper is to determine whether an analysis of the diatom flora a t the various levels could elucidate the causes of these changes.

METHODS AKD PROCEDURES By means of a Heller borer a core 14.5 meters in

length was taken from the sediments in Bethany Bog. From this core samples were selected a t one-meter intervals and prepared for the identification of diatoms. In order to determine the diatoms the material was first treated with nitric acid and potassium dichromate. It was then washed with distilled water until all traces of acid were removed and the solution was clear. The residue was then diluted to a constant factor, shaken, and a comparable amount was placed on each cover glass. After drying, the cover glasses were mounted i n Hyrax.

The slides on which these determinations were made are in the collection of the Academy of Natural Sci- ences of Philadelphia. The number in parentheses following the level depth is the number of the slide.

RESULTS OF ANALYSES OF SEDIMENTS The results of these studies are given below. With

the lists of species found at each level are ecological comments concerning the flora.

Surface Sample 0-iMcter Depth (A-4301-a) Eunotia andina Freng., E. exigua (Breb.) Rabh.,

E. lapponica Grun.: A, Cleve. Navicula termitina Ehr., N . festiva Krasske. Pinnularia interrupta f . minor Boye Petersen, P.

ruttneri Hust., P. viridis (Nitzsch) Ehr., P. viridis var. sudetica (Hike) Hust.: Pascher.

The specimens of diatoms were abundant. This is a typical temperate zone sphagnum bog flora. Chryso- phyceae spores were fairly common. No sponge spicules were observed.

Sample from Two-Meter Depth (A-4302-a) Eunotia bidentula W. Sm., E. pectinalis (Dillw.)

Rabh., E . robusta Ralfs: Pritchard, E. vcneris (Kiitz.) De Toni.

,Veidiunz iridis var. amphiyoniphus (Ehr.) Mayer. Pinnularia gibba Ehr., P. viridis (Nitzsch) Ehr. Tabellaria fenestrata (Lyngb.) Kutz. (fragments). The commonest species of diatoms were Eunotia

robusta and Neidium iridis var. amphigomphus. Many fragments of Tabellaria fenestrata and other diatoms were present. Sponge spicules were of frequent occur- rence. Chrysophyceae spores were very frequent. This is the flora of a water rich in humic substances.

Sample from the Three-Metcr Depth (A-4303-a) Cyinbella scotica W. Sm. Eunotia pectinalis var. minor (Kiitz.) Rabh., E.

pectinalis var. ventralis (Ehr.) Hust., E. robusta Ralfs: Pritchard, E. veneris (Kiitz.) De Toni.

Fragilaria pinnata Ehr., F . undata W. Sm. 2Ll elosira ambigua (Grun.) hIiill. (rare) Navicarla pupula Kiitz. (rare) Neidium iridis var. arnphigoniphzis (Ehr.) hIayer. Pinnularia gibba Ehr., P. viridis (Nitzsch) Ehr. Tabellaria fenestrata (Lyngb.) Kiitz. Vanheurckia rhoinboides var. rrassinervia (Breb.)

V. H. Many fragments of diatoms were seen. Chryso-

phyceae spores were fairly common. Sponge spicules were rare. This is a flora of dystrophic water or water rich in humic substances.

Sample from Four-Meter Depth (A-4304-a) Eunotia formica Ehr., E. inonodon var. major (W.

Sm.) Hust: Pascher, E . pectinalis var. minor (Kutz.) Rabh., E . pectinalis var. ventralis (Ehr.) Hust., E.

34

THE L)IATOM FLORA OF BETHANY BOG 35

robusta Ralfs: Pritchard, E . tenella (Grun.) Hust.: Pascher. E. zleneris (Kutz.) De Toni.

Savirula pupula K;htz. Pinnularia gibbu Ehr., P. latevittata var. domingen-

sis Cl., P. nzajor (Kiitz.) W. Sm., P . mcsogongyla Ehr.. P. viridis (Butzsch) Ehr.

Stauronois phocniccnteron (Nitzsch) Ehr. I'anlzeurckia rhonzboides var. crassinervia (Breb.)

1'. H. A rich diatom flora characteristic of water rich in

humic substances or swamp conditions was present. The most common species were Eunotia pectinalis and varieties, Pinnularia viridis, P . major, and P. latevit- tata var. doiningciisis. Chrysophyceae spores were common.

S d m p l c froriz Five-Mdcr Dcpth (A-4305-a) Ezrnotio monodon var. iiiajor (1%'. Sm.) Hust.:

Pascher, E. pectinalis (Dillw.) Rabh., E. pectinalis var. undulata (Ralfs) Rabh., E. pectinalis var. ven- tralis (Ehr.) Hust., E. robusta Ralfs: Pritchard, E. veneris (Kiitz.) De Toni.

Pinnularia gibba Ehr., P. legumen Ehr., P . major (Kiitz.) W. Sm.

Stouroneis phoeniccnteron (Xitzsch) Ehr. A bog flora typical of water rich in huniic substances

was present. It was dominated by Eunotia pectinalis and varieties, Pinnularia major, P. gibba, and P. zhidis. KO specimens of Cvclotella or ibfelosira were found. Chrysophyceae spores were common. Sponge spicules were fairly frequent.

Sponge spicules were fairly frequent.

Gomphonema parvuluin Kutz. Melosira ambigua (Grun.) PVIull. [See ( 2 ) , p. 195.1 Navicula americana Ehr. Scidiunz iridis var. amphigomphus (Ehr.) Mayer. Pinnularia braunii (Grun.) Cl., P . niridis (Nitzsch)

Tabrllaria fenestrata (Lyngb.) Kutz. T'anheurckia rhomboides var. crassinervia (Breb.)

V. H. This represents a transitional flora between a bog

and a somewhat mesotrophic lake. Common were Cy-lotella compta and C. stelligera. Also of very fre- quent occurrence were Melosira ambigua var. tcnuis, Eunotia major, E . monodon, and .Vas.irula amoicana. Chrysophyceae spores were common. Sponge spicu!es were of frequent occurrence.

Ehr.

Sample from Eight-Meter Depth (A-4308-a) .Imphora ovalis Kutz. Cyclotda compta (Ehr.) Kutz., C. stelligera C1. and

Cymbclla naviculiformis Auersw., C. scotica W. Sm. Eunotia monodon Ehr., E . monodon var. major (W.

Sm.) Hust.: Pascher, E. pectinalis (Dillw.) Rabh., E . robusta Ralfs: Pritchard, E. veneris (Kutz.) De Toni.

Grun.

Gonzphonema pnrvulirm Kiitz. Mclosira anzbigua (Grun.) Mull. ,Vavicula pupula Kutz. Pinnularia braunii (Grun. ) Cl., P. viridis (Nitzsch)

Ehr. Stauroncis phoeniccnteron (Nitzsch) Ehr. Tabellaria fenestrata (Lyngb.) Kutz., T . flocculosa Sample jroin Six-Meter. Dcpth (A-4306-a)

(Roth) Kutz. This is a transitional flora between a bog and a

mesosaprobic lake. The diatoms were abtulldant. es- pecially species of the genera Cyclotella and Mclosira. Common sl)ecies were Eunotia ,llonodon, E. 771ajor, E . pcctinalis, and Pinnularia viridis. Chrysophyceae spores were common. Sponge spicules were very fre- quent.

Cymbclla scotira tir. Sm. Eunotia bidentula lv. Sm., E. formica Ehr., E.

nloflodorz Ehr., E. monodon var. major (W.Sn1.) Hust.: Pascher. E . pfctinalis (Dillw.) Rabh., E . pectinalis var. ~ ~ ~ ? d u l a t u (Ralfs) Rabh , E. robusfa Ralfs: Pritch- ard, E. zlencris (Kutz.) De Toni.

.Yavic ula ainericana Ehr. Pinnularia gibba Ehr., P. major var. pulchclla Boyer. Stazironrvs phocnkentron (Nitzsch.) Ehr. A rich diatom flora which is characteristic of bog

water rich in humic substances was present. The most common diatoms were Ezinotia fornzica, E . inorlodon var. major, E . bidentzrla, E. pectinalis, and Pinnularia gibba. hlany Chrysophyceae spores were common. Coreoneis placcntuln Ehr. Sponge spicules were very frequent.

Sample from Nine-Meter Depth (A-4309-a) .4chnanthes PxiPa Grun.: cl. and Grun.,

A mpkora ovalis Iiiitz.

Cyclotella compta var. radiosa Grun.: V. H., C.

Cymbella naviculiformis Auersw., C. scotica W. Sni., Cyclotella compta (Ehr.) Kutz., C. stelligera C1. and

Diploneis snzithii (Brkb. ex. W. Sin.) C1. Cymbella scotica U'. Sm. C . turgida Greg. Eunotia arcus var. bidens Grun.: V. H., E arcus var. Eunotia formica Ehr., E. monodon Ehr., E. monodon uncinata (Ehr.) Grun.: V. H., E. diodon Ehr.,

var. major (W. Sm.) Hust.: Pascher, E. vcneris E . monodon var. major (W. Sm.) Hust.: Pascher, E. (Kutz.) de Toni. monodon Ehr., E. pectinalis (Dillw.) Rabh., E. pec-

tissima var. W'ptocephala Grun.: V. H.

stelligera C1. and Grun.

C. turgida Greg., C. ventricosa Ag. Sample froin Seven-Meter Depth (A-4307-a)

Grun.

36 THE DIATOM FLORA OF BETHANY BOG

tinalis var. ventralis (Ehr.) Hust., E. robzista Ralfs: Pritchard, E. veneris (Kiitz.) De Toni.

Eucocconeis perella (Kiitz.) C1. Fragilaria construens (Ehr.) Grun., F . construens

var. binodis (Ehr.) Grun., F . construens var. venter (Ehr.) Grun.: V. H., F . pinnata Ehr.

Gomphonema acurnninaturn var. coronatunz (Ehr.) Rabh., G. gracile Ehr., G. parvu lum Kiitz.

Ilfelosira ambigua Mull. A'avicula dicephala Ehr., S. laterostriata Hust., N .

oblonga (Kutz.) S. pupula Kiitz., N. radiosa Kiitz., N . subtilissima C1.

Pinnularia gibba Ehr., P . nodosa (Ehr.) M'. Sm., P. viridis (Nitzsch) Ehr.

Stauroneis phoenicenteron (Nitzsch) . Synedra parasitic-a (b'. Sm.) Hust. Tabellaria jenestrata (Lyngb.) Kiitz. A very diverse flora characteristic of a soft water,

somewhat mesotrolphic lake with some humic sub- stances. but definitely not of bog-like conditions was present. Species of Eunotia were common, but the flora was dominated by Cyclotella rompta var. radiosa, Tobellaria fcncstrnta, Fragilaria ronstruens, and Melo- sira czinbipa. Chrysophyceae spores were very com- mon. Sponge spicules were very frequent.

Slrmplc from Tcn-Mcter D c p t h (A-43 10-a) '4mphoro ovalis Kiitz., C . compta (Ehr.) Kiitz.,

C . compta var. radiosa Grun.: V. H., C. stclliycra C1. and Grun.

Cynibella aspera (Ehr.) Heribaud, C. cistula (Hempr.) Kirchn., C. nzicrocephala Grun.: V. H., C. naviculijormis Auserw., C. scotica W. Sm.. C. turgida Greg., C. ventricosa '4g.

Diploneis marginrJtriata Hust., D. smithii (BrCb.: W. Sm.) C1.

Eicnotia monodon var. major (LV. Sm.) Hust.: Pascher. E . pectinalis var. minor (Kiitz.) Rabh., E. robzista Ralfs: Pritchard, E. vcneris (Kutz.) De Toni.

Fragilaria pinnatu Ehr., F . virescens Ralfs. Goniphoncina acuniinatuin var. coronaturn (Ehr.)

Melosira n i n bigua JI iill. iVitzschia amphibia Grun. Pinnularia gibba Ehr. Stauroneis phoenicenteron (Nitzsch) Ehr. Tabellaria jcncstrata (Lyngb.) Kutz. A very rich and diverse flora was dominated by

Cyclotclla compta and Tabellaria jenestrata. The species of diatoms indicate a rich plankton as well as a well-diversified benthic flora. The lake was meso- trophic. Chrysophyceae spores were very common. Sponge spicules were very frequent.

Sainple from Eleven-Meter D e p t h (A-43 1 1-a) Cyclotella coinpta var. radiosa Grun.: V. H., C. stel-

Rabh., G. constrictunz var. capi tatum (Ehr.) V. H.

ligera C1. and Grun. Cymbella scotica W . Sm., C. turgida Greg. Eunotia zleneria (Kiitz.) De Toni. Fragilaria pinnata Ehr., F . vaucheriae Kiitz. Gomphonema acuminatum var. coronaturn (Ehr.)

Rabh., G. angustata Kiitz.: Rabh., G. parvulum Kiitz. Melosira ambigua Miill., M . ambigua Miill. (See

Patrick, 1940, p. 195.) Nazlicula atomus (Kutz.) Grun.. S. pupula Kiitz. Nitzschia amphibia Grun. Tabellaria pocculosa (Roth) Kiitz. The flora was not as diverse in species as those a t

9 and 10 meters. It was rich as to specimens and dominated by Cyclotella compta. Melosira ambigua, M . anibigua var. tenuis, and Fragilaria pinnata were also common. Sponge spicules were very frequent. Chrysophyceae spores were common.

Sample f r o m Twe lve -Meter D e p t h (A-43 12-a) Cyrlotella compta (Ehr.) Kiitz. Cymbella ventricosa Ag. Diploneis marginistriata Hust., D. ovalis (Hilse) C1. Eunotia veneris (Kiitz.) De Toni. Fragilaria bicapitata A. Mayer, F . brcvistriata

Grun.: V. H.. F . construens var. venter (Ehr.) Grun.: V. H.

Gomphonema parvulum Kiitz. ATaz&xda atomzis (Kutz.) Grun., S. exigua var.

Navicula subtilissima C1. Tabellaria jenestrata (Lyngb.) Kiitz. This flora was very similar to that at 11 meters but

not as diversified. I t was much richer as to specimens than the flora at 13 meters. The dominant species were Tabelluria fenestrata, Cyclotella c-onzpta, and Fragil- aria construens and varieties. Chrysophyceae spores were abundant. A few sponge spicules were present.

capitata Patr., A;. pseudocutiformis Hust.: Pascher.

Sainple froin Thirteen-Meter D c p t h (A-43 13-a) Achnanthes oestrupii (CI.) Hust.: Pascher. Amphora ovalis Kiitz. Cyclotella cotnpta (Ehr.) Kutz. Cynibella ventricosa Ag. Fragilaria construens (Ehr.) Grun., F . construens

var. binodis (Ehr.) Grun., F . construens var. subsalinn Hust., F . pinnata Ehr., F . virescens Ralfs.

Navieula pupula Kiitz. Pinnularia gibba Ehr., P. interrupta W. Sm., P .

Stauroneis anceps Ehr., S. phoenicenteron (Nitzsch)

Syncdra parasitica (W. Sm.) Hust.: Pascher. This is a diatom flora characteristic of a soft water,

oligotrophic to somewhat mesotrophic lake. As one would expect, the flora was not too well developed. No diatom flora was found at 14 or 14.5 meters. Roth

inesolepta (Ehr.) W. Sm., P. viridis (Nitzsch) Ehr.

Ehr., S. smithi i Grun.

THE DIATOM FLORA OF BETHANY BOG 37

Chrysophyceae spores and sponge spicules were of in- frequent occurrence.

DISCUSSION O F RESULTS

The results of these studies indicate that there was no diatom flora below 13 meters. The first diatom flora was at 13 meters. In general aspects it was very similar to the diatom flora found a t the beginning of diatom succession in Linsley Pond(3). The flora was limited both as to number of individuals and of species.

At 1 2 meters the diversity of species and the number of individuals had increased considerably. It was, as at 13 meters, very similar to the early flora in Linsley Pond. The lake becomes increasingly eu- trophic from 11 to 9 meters. The floras a t 10 and 9 meters were very rich as to individuals and species. Both plankton and benthic forms were common. At 9 meters the genus Ezinotia was for the first time repre- sented by many species and individuals. The com- monness of this genus indicates the trend of develop- ment. At the 8 and 7 meter levels the lake was in a transitional state. This is indicated by the continuing occurrence of species of Cyclotella and Mdosira with a decided increase in species characteristic of bogs and waters rich in humates, such as certain species of Eirnofitr, Pinnularia, and Savicula. At these levels the development of this body of water digressed greatly from Linsley Pond, the former becoming a bog and the latter a eutrophic lake.

From six meters to the surface bog-like conditions were evident. The flora was dominated by species of Eunotiu and Pinnularia, which are characteristic of water rich in humates.

The occurrences of Chrysophyceae spores were com- mon or very frequent from 12 meters to the surface. At 1 2 meters they were more abundant than a t any other level. At 13 meters they were relatively infre- quent in occurrence.

The first occurrence of sponge spicules in any num- bers was a t 11 meters where they were very frequent. Their frequency remained approximately the same to 6 meters. It is at this level that the lake assumed very definite bog-like characteristics. The spicules gradual- ly decreased till a t the 0-meter level none were ob- served.

Vallentyne(4), as a result of his studies, divides the lake into five phases.

1. Clay sediments, low in organic and pigment contents. Characteristic of the 15-13 meter level. 2. Increase in organic and pigment concentra- tions. Characteristic of the 13-12 meter levels. 3. A pigment minimum zone with reduced organic content. Characteristic of the 11-10 meter !evels.

4. Pigment maximum zone, very high in carotene and glucose. Characteristic of 9.5-8 meter levels. 5 . Dystrophic zone, relatively high in rhodovio- lascin; reduced amount of myxoxanthin; and low content of other pigments. The total chlorophyll was high in this zone. The increase in pigments at the 5-4 meter level may indicate a separate phase in this zone. These phases of development of Bethany Bog are

well supported by the diatom studies. In the first phase a diatom flora was only found a t the 13-meter level. The kinds of species and numbers of speci- mens would indicate that the productivity of the lake was relatively low.

The high organic content of the 12-meter level may well be due to higher plants, as the diatom flora would not be indicative of this high content. Such plants would also contain a considerable amount of pigment.

During phases three and four a rich mesosaprobic diatom flora existed in the lake. At this time the lake supported a well-developed plankton flora. The diminishing of light penetration due to this plankton fora may have produced conditions unfavorable for the growth of higher plants. This would cause a reduction in organic content. The high amount of carotene in phase four may be due to the excellent diatom Aora during this period.

The diatom flora would indicate that during the 8-7 meter levels the lake was in a transitional period. This according to VaIlentyne(4) is substantiated by the appearance of the dry mud. The dry mud was gray-black in appearance below eight meters and black in appearance above eight meters. Vallentyne states that beginning a t eight meters there was a gradual rise in ignitible matter from 58.6 per cent to 75.7 per cent a t two meters, and 94.5 per cent a t the surface. This rise in ignitible material may well be due to the fact that with the appearance of bog conditions there was a great increase in growth of higher plants and mosses. This is substantiated by the fact that at the surface Bethany Bog is a sphagnum bog with 94.5 per cent ignitible material.

Phase 5 , the dystrophic zone, is very well substanti- ated by the diatom flora. The kinds of species are typical of bogs and waters high in humates which are found in the lakes and streams of the Pocono Plateau and in the southern New Jersey streams and bogs.

REFERENCES 1. Deevey, E. S., Jr., (1943). Additional pollen analyses

from southern New England. '4m. 1. Sci., 241, 717-752. 2 . Patrick, Ruth, (1940). Diatoms of northeastern Brazil.

Par t I. Proc. Acad. Nut. Sri. Phila., 92, 191-226. 3. __ , (1943). The diatoms of Linsley Pond, Connecti-

cut. Proc. Acud. Nut . Sci. Phila., 95, 53-110. 4. Vallentyne, J . R. W., (1953). Organic pigments in lake

sediments. Doctoral dissertation, Yale University. [Prelimin- ary note in press in Science.]