Filter-feeding Invertebrates Research Articles

Oxygen uptake and haemolymph oxygen tension in the stalked barnacleCalantica spinosa

Abstract Oxygen uptake (VO2) and haemolymph oxygen tension (PO2) were determined for the intertidal, stalked barnacle Calantica spinosa (Quoy & Gaimard) during submersion and aerial exposure at 15°C. VO2 did not change significantly with emersion, but peduncular sinus haemolymph PO2 increased significantly after 1–2 h in air. The maintenance of aerobic metabolism during aerial exposure described for C. spinosa contrasts with the depressed VO2 generally reported for intertidal filter-feeding invertebrates on emersion. The increased haemolymph PO2 reported for stalked barnacles in air (characteristic of terrestrial, air-breathing decapod crustaceans) is in contrast to the respiratory pattern displayed by other aquatic invertebrates during aerial exposure. The respiratory physiology of C. spinosa in aquatic and aerial environments is discussed with particular reference to its feeding behaviour.

Anatomical distribution of sterols in some filter feeding invertebrates

The sterol composition of separate organs of the filter-feeding invertebrates Anodonta cygnea, Mytilus galloprovincialis and Ascidia sp. is described. The distribution of the individual free sterols and sterol esters is compared in eight different organs of A. cygnea and in five organs of M. galloprovincialis and Ascidia sp. Hypotheses about the metabolism and the physiological functions of sterols in these organisms are suggested.

A Nutritional Role for Amino Acid Transport in Filter-Feeding Marine Invertebrates

SYNOPSIS. Filter-feeding invertebrates are exposed to a small but continuous source of potential foodstuffs in the form of dissolved free amino acids (DFAA). Studies with two genera of bivalve molluscs, Mytilus and Modiolus , indicate the existence of carrier-mediated transport processes for DFAA, and that these processes are capable of a net accumulation of substrate from external solution. The kinetics of DFAA transport in bivalve gill, the primary organ for uptake, reveal these processes to be well-adapted for the efficient utilization of substrate at the extremely low concentrations (approximately 1 μM) characteristic of the water column: Michaelis constants for uptake are in the micromolar range, resulting in transport rates that are a significant fraction of the maximum capacity of the system. Comparison of potential rates of DFAA accumulation to rates of oxidative metabolism suggest that DFAA can serve as an important nutritional supplement to these animals. Future work should emphasize new analytical procedures, including the use of high performance liquid chromatography, to identify levels of DFAA in specific environments and rates of net DFAA uptake into organisms from these habitats.

Stratigraphy and Sedimentary Environments of Lower Cretaceous Rocks, Southern Western Interior

Upper Albian rocks crop out on the southern edge of the Western Interior province in Kansas, Oklahoma, northeastern New Mexico, and southeastern Colorado. Four formations are recognized in the several regions: Cheyenne Sandstone and Kiowa Formation in Kansas and western Oklahoma, Tucumcari Formation in New Mexico, and Purgatoire Formation consisting of the Lytle Sandstone Member and the overlying Glencairn Shale Member in southeastern Colorado and parts of adjacent states. Recognition of four ammonite-bivalve zones indicates that the basal Kiowa and much of the Cheyenne are time equivalents of the uppermost Fredericksburg rocks in Texas. Most of the Kiowa is equivalent to Washita units through the Denton Formation in North Texas. The Tucumcari and Glencairn correlate with upper parts of the Kiowa in southern Kansas. Part of the Lytle is equivalent to lower parts of the Kiowa and part may be older than the basal Kiowa. These rocks record the transgression and regression of the Early Cretaceous sea from the Gulf Coast region of the United States. The sequence consists of coastal-plain, sea-margin, and open-sea deposits. Cross-bedded, conglomeratic sandstones of the Cheyenne and Lytle were deposited by fluviatile processes on a coastal plain; laminated and thin-bedded sandstone and mudstone of the Kiowa, Purgatoire, and Tucumcari that commonly bear marine infaunal and epifaunal mollusks originated in the sublittoral margin of the seaway; and the dark-gray shale of these three formations, locally bearing a fauna of burrowing detritus- and filter-feeding invertebrates, originated as mud in the open seaway.

Chain Formation by Phaeodactylum

Phaeodactylum tricornutum (Bohlin) is a small marine diatom, with relatively unexacting growth requirements. Since the isolation of the original culture1 several others have been started, and subcultures have been sent to many countries. The rate of growth in relation to nutrition and environmental conditions has been widely studied in unialgal and bacteria-free culture, as well as in mass culture. The species is also extensively cultured as food for rearing marine larval forms and filter-feeding invertebrates. Considerable speculation has centred on its taxonomic position2.

Some quantitative aspects of feeding in sabellid and serpulid fan worms

The rate of filtering has been examined in a series of sabellids and serpulids of widely different size, using suspensions of colloidal graphite and algal cultures. The filtering rates have been expressed as individual rates, as the volume strained per unit fresh weight, and per unit weight of the crown. It may be concluded that the smaller fan worms filter at a relatively higher rate than the larger. This is achieved partly by the relatively larger crown. Free swimming algae escape through the crown; only inert particles down to 1–2 μA are retained, implying that fan worms depend on suspended detritus alone. The filtering rates are briefly compared with those of Chaetopterus and some other filter-feeding invertebrates.

QUANTITATIVE ASPECTS OF FILTER FEEDING IN INVERTEBRATES

QUANTITATIVE ASPECTS OF FILTER FEEDING IN INVERTEBRATES

WATER FILTRATION BY THE BAY SCALLOP, PECTEN IRRADIANS, AS OBSERVED WITH THE USE OF RADIOACTIVE PLANKTON

1. The water filtration by the bay scallop, Pecten irradians, was studied by following the clearing of suspensions of plankton cells that had been made radioactive. The use of radioactivity measurement techniques for such studies of the rate of water propulsion of filter-feeding invertebrates by the indirect method allows detection of slight changes in cell numbers in dilute suspensions and is advantageous for investigation of the feeding activities of lamellibranch molluscs.2. The scallops were observed to filter the water passed through their gills very efficiently with apparently complete retention of Chlamydomonas and Nitzschia cells after adjustment to the immersion in the suspensions. The rapid rate of decrease of suspended plankton was not continued, however, for there was evidence of a decrease in the efficiency of the gills and increasing return to the suspension of phytoplankton cells previously removed.3. The bay scallop has a relatively high rate of water propulsion, probably cortrelated with ...

Contributions to our knowledge of the smaller marine algae

Our lack of knowledge of nanoplankton organisms is due largely, no doubt, to the necessity for examining them alive and the comparative difficulty of observing them, and also to their being, apparently, of no more than indirect importance in the ecology of fishes, except when their occasional presence in great abundance has been accompanied by unfavourable hydrographical changes. An adequate survey of life in the sea is bound to take them into account. Since they are frequently abundant, at least in inshore waters, and propagate rapidly, they probably form an important constituent of the food of adult filter-feeding invertebrates. They are likely to be of still greater importance as the essential food of many planktonic larvae, particularly in the early stages. Oyster larvae(Ostrea edulisL.) can ingest nothing larger than about 10 μ and appear to rely for food on minute flagellates (Cole, 1936,1939; Bruce, Knight & Parke, 1940). The food of other marine larvae has not been closely investigated.

A New Method of Ciliary Feeding in the Brachiopod Neothyris lenticularis

THE Pygocaulian Brachiopod Neothyris lenticularis possesses sets of ciliated filaments similar to those in other invertebrate filter feeders. Studies on this form, however, have shown that the method of feeding is very different from that in other ciliary feeders—Lamellibranchs1, certain sedentary Gastropods2, Cryptocephalous Polychaetes3, Tunicates and Amphioxus4, Entoproct and Ectoproct Polyzoa5,6 and Crania7. There are two fundamental points of difference, namely, the function of the filaments and the direction of beat of the cilia on the filaments.