Quiet Pools Research Articles

Evoked potential and behavioral hearing thresholds in nine bottlenose dolphins (Tursiops truncatus)

Auditory evoked potentials are popular for assessing hearing in marine mammals because they do not require the same access to and training of animals as behavioral methods; however, within-subject comparisons of behavioral and electrophysiological thresholds are still necessary to benchmark evoked potential results against the more universally accepted behavioral data. In this study, auditory thresholds were measured in nine dolphins using both behavioral and electrophysiological methods. Subjects included eight males and one female, ages 21-43 yrs. Some had a full-range of hearing and others exhibited high-frequency hearing loss. Tests were conducted in-air, in San Diego Bay, and/or in quiet pools. Hearing test stimuli included frequency-modulated, amplitude-modulated, or pure tones projected in the direct field or via a "jawphone" contact transducer. Comparisons reveal good agreement between the evoked potential and behavioral methods, particularly when the testing environments, stimulus delivery methods, and stimulus waveforms are similar. The results show that evoked potential thresholds obtained in a variety of conditions provide reasonable approximations to underwater sensitivity, especially with respect to the shape of the audiogram and the upper limit of hearing.

Archeological optics: the very first known mirrors and lenses

The primary objective of the paper is to review histories of early known mirrors and lenses. Squinting/pinholes/slit apertures provided initial visual enhancements; quiet pools of water served as early mirrors. Manufactured mirrors appeared during the Stone Age 8000 years ago in Çatal Höyük in Anatolia within modern Turkey. The next generation mirrors were Mesopotamian and Egyptian. Oldest lenses, extraordinary in quality and complexity with built-in illusion, were in use in Egypt 4575 years ago. Simpler lens forms appeared between 3932(?)–3500 years ago, probably in the Levant/Eastern Mediterranean basin. The main outcomes are: (1) civilized societies had mirrors by about 4000 years ago, including China, India (e.g. Lothal) and New World societies. (2) Siberia and China had different mirror designs than Western areas. (3) Only crystalline materials were used in New World mirrors. (4) The author located an Egyptian lens in Boston having original lens design, this extended this lens' utilization by ca. 800 years to 3070–2656 years ago. These histories are fascinating!

Growth and recovery of temporary threshold shifts in a dolphin exposed to midfrequency tones with durations up to 128 s

Auditory thresholds at 4.5 kHz were measured in a bottlenose dolphin (Tursiops truncatus) before and after exposure to midfrequency tones at 3 kHz. Experiments were conducted in relatively quiet pools with low ambient noise levels at frequencies above 1 kHz. Behavioral hearing tests allowed for thresholds to be routinely measured within 4 min postexposure, and tracked recovery for at least 30 min postexposure. Exposure durations ranged from 4 to 128 s at sound pressure levels ranging from 149 to 200 dB re: 1 μPa. Sound exposure levels ranged from 155 to 217 dB re: 1 μPa2/s. Temporary threshold shifts at 4 min postexposure (TTS4) of up to 23 dB were observed. All thresholds recovered to baseline and pre-exposure levels, most within 30 min of exposure. [Work supported by the U.S. ONR.]

Looking back at The Quiet Pools

Looking back at The Quiet Pools

Aspects of the Life History of the Stippled Darter Etheostoma punctulatum

Aspects of the life history of the stippled darter Etheostoma punctulatum were studied in the Spring River in SW Missouri. Females attained a maximum standard length of 85 mm and males 83 mm. Both sexes lived slightly more than 4 years. Sparvning began in early February and continued through late May. Males were mature at 1 year of age while only those yearling females at least 49 mm long produced mature ova. Females contained an average of 447 ova2-0.55 mm in diam in two distinct size modes and a group of smaller developing ova. The presence of these distinct size groups of ova throughout the spawning period indicates that two or more clutches of eggs were produced by each mature female. The fertilized eggs were 1.6 mm in diam and hatched in 11 days at 16 C. The diet was made up primarily of crustaceans and aquatic insect larvae. INTRODUCTION The stippled darter Etheostoma punctulatum is a robust darter and the largest in the subgenus Ozarka, reaching 88 mm SL (Kuehne and Barbour, 1983). This darter is distributed throughout the Ozarks where it is most often found in small creeks and spring branches having clear water with permanent flow and silt-free bottoms. Pflieger (1975) indicates it may be found in quiet pools and backwaters where it hides around large rocks or in beds of organic debris. Although not uncommon within its known range of distribution, there are very few populations large enough to permit taking the numbers necessary for life history analysis. Fishes restricted to small headwater streams are frequently subjected to wide fluctuations in environmental conditions. This study was begun with samples being taken in two streams but was terminated in Weaubleau Creek in Hickory Co., Missouri, when dry weather reduced the stream to a few isolated pools and destroyed the darter population. The danger faced by darter populations in headwater locations is also increased by human activity. The second stream location is immediately downstream from a troutrearing facility through which nearly all water in the stream passes. Cleaning of the trout pools in February 1983 produced silt which covered the gravel bottom of the sampling area to a depth of 0.5 m in many places. This site is also 2-km upstream from a well-publicized source of dioxin contamination in the watershed and fishes in the area are known to be concentrating this substance. Activities affecting this stream section may eliminate the desirable habitat which sustains populations of Etheostoma cragini, E. microperca and E. punctulatum among others. Important contributions on life history and ecology of other members of the subgenus Ozarka have been made, but a basic study of the stippled darter has been lacking. Life history features of the threatened paleback darter Etheostoma pallididorsum were determined from preserved museum specimens by Hambrick and Robison (1979). Taber et al. (1986) discussed several aspects of the life history of E. cragini; Boschung (1979) commented on the life history and distribution of E. boschungi, and Etnier (1970) made significant contributions to the known distribution of E. trisella. More recently Ryon (1986) studied the life history and ecology of E. trisella. Information gained by studying the stippled darter is important to the information base which could be used in conservation of this and other less abundant species of its subgenus.

Feeding Structures of Two Atyid Shrimps, with Comments on Caridean Phylogeny

ABSTRACT Atyainnocous and Potimirim glabra (Atyidae) occur in permanent and temporary freshwater streams in the Atlantic and Pacific drainages of Panama. Their mouthparts, mandibles, and foreguts are compared to test the hypothesis that these structures are related to diet. Atya innocous occurs in moderate to fast-flowing streams, feeding on minute particles collected from the water column or bottom. Potimirim glabra inhabits quiet pools, scraping periphyton from leaf surfaces and decaying organic detritus. The feeding appendages of both species arc modified for handling fine particles of food. The mandibles have a strong incisor process but are not used for crushing large food items. The primitive nature of the mandible and foregut suggests the placement of the family Atyidae at the base of the caridean evolutionary tree. The use of the foregut in the construction of phylogenies within the Decapoda is discussed.

Life History of the Brindled Madtom Noturus miurus in Mill Creek, Illinois (Pisces: Ictaluridae)

The life history of Noturus miurus was studied from collections made at Mill Creek, Pulaski Co., Illinois, between 27 August 1978 and 27 October 1979. A total of 318 specimens ranging in age from 1-36 months were collected and six nests with guardian males were found. Noturus miurus is syntopic with N. nocturnus in Mill Creek; N. miurus usually occupied mud-bottomed, debris-ridden pools and N. nocturnus generally inhabited rocky or brushy riffles. Males were sexually mature at 2 years, and during the breeding season their heads, lips and genital papillae were swollen. Females had mature ova from May to July; some females reached sexual maturity by 1 year. The number of mature oocytes produced by a female ranged from 42-90 (x = 66.2). The nesting season spanned at least 19-28 June 1979 when water temperatures ranged from 24-27 C. Six nests, each containing a single clutch of eggs and each guarded by a single male, were found in 355-ml beer cans and under flat rocks in quiet pools. Clutch size ranged from 56-81 (x = 66.2); eggs were spherical and yellow or amber in color and ranged in size from 3.4-3.8 mm (x = 3.5). Clutches of eggs incubated in the laboratory at 25 C hatched in 189 to 215 hr with a hatching success of 86%o. Individual Noturus miurus grew at a decreasing rate in standard length and at a constant rate in body weight for at least 3 years. One-half of the 1st year's mean growth in length was reached in ca. 8 weeks; about 10 months was required to attain one-half of the 1st year's mean weight. The largest fish collected at Mill Creek was 79 mm. Aquatic dipteran larvae and pupae, ephemeropteran naiads, trichopteran larvae and adult isopods were the predominant food items in the 107 stomachs examined. Diversity of diet tended to increase with increasing size. Noturus miurus was frequently parasitized by nematodes and less frequently by flukes and parasitic copepods. INTRODUCTION The 25 described species of Noturus are mostly nocturnal and cryptic in habits. Of the 25 species, only 12 have had any aspect of their ecology and life history described, and much of the information is anecdotal and limited to observations conducted over a brief period. Only one species, Noturus exilis, has been the subject of a thorough published life history study (Mayden and Burr, 1981). A review of ecological information on Noturus is presented by Taylor (1969) and updated in Mayden and Burr (1981). To expand our knowledge of the natural history of Noturus we have, for the last three years, been conducting life history studies of N. miurus, N. exilis and N. nocturnus. The purpose of this paper is to present information on the reproductive biology, age, growth, diet and demography of the brindled madtom Noturus miurus in southern Illinois. The external morphology, distribution and taxonomy of Noturus miurus were investigated by Taylor (1969), who also included original observations on nesting habits and development of individuals from Huron River, Michigan. Menzel and Raney (1973) reported egg counts of specimens from Cayuga Lake, New York. Noturus miurus is wide-ranging, occurring in portions of the Great Lakes and lower half of the Mississippi River basin, the entire Ohio River basin and the Pearl River and Lake Pontchartrain drainages on the central Gulf Coast.

Studies on the functional morphology and ecology of the atyid prawns of Dominica.

Six species of atyid prawns, representing five genera, occur in streams on the West Indian island of Dominica (figures 1-6). The ecology and habits of each are described and the relation of features of gross morphology to ways of life noted. Xiphocaris elongata, the most primitive living atyid, is a lightly built prawn whose adult habits are related to life in quiet pools in streams. An agile species and an excellent swimmer, it picks up individual small food particles with specialized chelipeds (figures 18 and 19) that differ from those of all other atyids and manipulates them with mouthparts (figure 77) which, while highly complex, are more primitive than those described for any other member of the family. Atya innocous and A. scabra, representing perhaps the most specialized atyid genus, are very similar in gross morphology and are robustly built ambulatory species. A. innocous is common in a variety of situations: A. scabra is rare and has been found only in fast-flowing water. Both have chelipeds whose three distal segments are extremely specialized (figure 36) and whose propus and dactylus are armed with an exceedingly complex array of long, slender bristles. These can be used either as brushes for collecting finely particulate detritus (figures 58-60) or as filtering fans (figures 68 and 69) which, held passively in flowing water, extract suspended particles. The Atyidae is unique among the Malacostraca in having representatives that filter passively by means of the chelipeds. The bristles (figure 40) are extended (figure 49), not by muscles, of which there are none in the distal parts of the propus and none anywhere in the dactylus, but by hydraulic forces. The return of the bristles to rest is by means of a cuticular spring. Some of the bristles of A. innocous are armed distally with minute denticles (figures 41 and 42) that facilitate scraping and sweeping: no such are present in A. scabra. The difference is related to the relative importance of scraping in the two species: A. innocous scrapes frequently, A. scabra seldom. Finely particulate food is transferred and manipulated by the extremely complex oral machinery (figure 78). One of the most elaborate parts of this is a teaselling device in which components of the maxillae and first maxillipeds participate (figures 80 and 81). The feeding mechanism is described. Morphologically and functionally Micratya poeyi can be regarded as a miniature version of Atya. It can both sweep and filter. Potimirim glabra is rare in Dominica and its habits but little known. Morphologically it is similar to, but more primitive than, Micratya. Its cheliped bristles are clearly specialized for sweeping and show few signs of being used for passive filtration. Jonga serrei occupies a separate and well-defined niche in the quieter parts of streams. For this it shows many morphological specializations and lacks such attributes as stout claws and robust walking legs that are the hallmark of its relatives living in fast-flowing waters.

The Systematic Status and Life History of Hyla verrucigera Werner

are junior synonyms of Osteocephalus verrucigerus, a species known from the Amazonian slopes of the Andes from southern Colombia, Ecuador, and central Peru. Males have tuberculate skin dorsally, whereas females are smooth. The skull of 0. verrucigerus is completely roofed, smooth, and lacks a dermal sphenethmoid. The heavily pigmented tadpoles have two upper and five lower tooth rows and develop in quiet pools in streams.

The Biology of the Stream

Many biology instructors overlook the possibilities of a stream, especially a creek or brook, as a teaching aid. They suppose that running water represents a highly specialized environment, that the biology of the stream is too complicated for elementary study, and that the bulk of freshwater life is in the ponds and lakes instead of the streams. In coimiparison with other inland habitats, running water is actually rather broadly generalized, for even the most turbulent mountain torrent has some quiet pools and backwater areas. Adjustments of plants and animals to physical environmiental conditions are often nore obvious in running water than in still water or on land. If there is a streaimi near enough to be readily available for field observation it should not be neglected. The suggestions in this paper come from actual experiences of teachers and pupils fromn kindergarten to university, involving both plains and mountain streams. Any interested teacher can enlarge upon and modify them to fit any particular type of running water habi-' tats available in his own community. A small stream may be an important source of biological material for general observation, laboratory study, aquariuLm stocking or preservation for future use. Attached to stones and sticks in swift currents may be found various green algae and water moss. Water cress abounds in spring-fed brooks. Spirogyra and other filamentous algae, Euglena and similar microorganisms live in quiet pools back of large rocks, fallen logs and other obstructions. Arrowweed or arrow-head, reeds, spatterdock and cattails are to be found in side pools and cutoffs. Pondweeds sometimes occur in slow streams. Duckweed and other floating plants may be found in quiet pools and backwaters. Protozoa of many kinids occur in still pools and ainong attached algae in currents. Rotifers are frequently associated with them. Sponges are found on submerged sticks in clear cool streams. Hydras are common on vegetation growing in clear water in slow streams or pools in sunny places. In suitable locations they may be founLd the year around. Bryozoa are found on stones and logs in clear water, either in pools or in currents. They are not prominent in appearance anld are often overlooked. Planaria and similar flatworms are found attached leech-like to the bottoms of stones in moderate to swift currents. Their color often blends so well with that of the stones that they are easily overlooked. There are two common types of roundworms in streams. The almost microscopic nematodes are very generally distributed in slow muddy-bottom streams; the larger hairworms ( horsehair snakes) are found in clear water in pools or slow currents, generally in or above bottom vegetation. Annelids are also represented by two common types, bristleworms and leeches. The former are abuncdant in muddy bottomus and decaying vegetation; the latter are found in pools, on sticks and rocks in slow streams, and attached to turtles and frogs. Clams are generally buried in mud or sanid in the shallower parts of slow

Ice in the northern streams of the United States

Much has been observed and written about the open‐summer phase of river‐behavior, little about the winter phase. This paper will attempt to describe objectively some of the less well‐known phenomena of the winter phase of a river's annual cycle.The freeze‐up—With the coming of cold weather, the water gradually is cooled, its temperature being intermediate between the cold air on the surface and the warm rock of the river‐bed that still retains the heat of the summer. Within the mass of the water, temperatures tend to be uniform, the water being continually stirred by turbulent currents. This uniformity is further aided by the sinking of the cold, dense surface‐layers and the welling up of the warm, lighter bottom‐layer. Occasionally temperature‐stratification occurs in deep, quiet pools. The water cools degree by degree until the entire mass is close to the freezing‐point. Finally, the surface‐film of water is cooled below the freezing‐point and suddenly changed into needle‐like crystals of ice that are slightly lighter than water.