Nitrogen content in 10 plant samples of widely varying concentrations of N, P, and K was measured by a H2SO4—H2O2 ashing procedure and the AutoAnalyzer system and found comparable to nitrogen content obtained by conventional Kjeldahl analysis. Phosphorus content measured by the AutoAnalyzer system on the same H2SO4‐H2O2 ashing was similar to that obtained by dry‐ashing combined with the molybdo‐vanadate procedure. Potassium analyses on the solutions from the two ashing procedures by atomic absorption spectroscopy were comparable. Details are presented for simultaneous N and P analysis by the AutoAnalyzer and for K analysis by atomic absorption on plant material performed on a single H2SO4‐H2O2 digest at a rate of 160 samples per week by one technician.

Sedimentary materials from eroding bluffs, suspended solids in streams, and lake bottom sediments from Lakes Ontario and Erie were cultured with the alga Scenedesmus quadricauda (Turp.) de Brebisson in modified Rodhe's medium with the sediments as the sole source of P. P uptake by the algae was related to the amount of nonapatite inorganic phosphorus in the sediments. Apatite phosphorus was not used, and the bluff samples, in which over 90% of total P was in this form, did not support algal growth. The nonapatite inorganic P fraction was highly correlated with the amounts of inorganic phosphorus extracted by three standard techniques for estimating "available P" (extraction by NaOH and nitrilotriacetic acid solutions and by H-resin) and cell uptake equaled NaOH-extractable inorganic P in several instances. Uptake of P by the cells varied from 8 to 50% of total P and from 38 to 83% of nonapatite inorganic P when measured directly. Organic phosphorus in the sediments was not utilized by the algae. Percentage utilization of total P was in general highest when total P concentration in the sediments was itself high.

No abstract

Soybeans were stored at two temperatures, 20~ and 30~ and two relative humidities, 65% and 85%. The amount of protein extracted into soymilk decreased by about 14% of the initial extractability in all cases after eight months of storage. The decline in protein extractability could not be explained by decreases in pH, nor by loss of solubility of certain protein components. Tofu made from beans that were stored at 85% relative humidity became less uniform in microstructure toward the end of the storage period. The volume of whey produced increased with bean storage time.

On the basis of extensive sampling and echo sounding, three major lithological units are recognized in the main basin of Lake Huron: (1) glacial till and bedrock; (2) glaciolacustrine clay; and (3) postglacial mud. Sand is a lesser unit in the Huron surficial sediments. Owing to the wide range in bathymetric complexity, postglacial muds occur in basins of three distinct types:Type A. Regular basins in which mud forms a continuous cover.Type B. Irregular basins with undulating bottom topography. Glaciolacustrine clays outcrop in the crests and mud fill occurs in the hollows. Mud cover is greater than 50%.Type C. As for type B but with mud cover less than 50%.The sediment distribution pattern is essentially simple with a natural superposition of sediment units reflecting the glacial and postglacial history of the lake. A bedrock escarpment from Point Clark to Thunder Bay divides Lake Huron into two distinct morphological regions. To the south of the escarpment, the lake has a gentle topography. A second low amplitude escarpment, trending northeast from Ipperwash, divides the southern region of the lake into two large depositional basins. To the north of the major escarpment, the lake is much deeper and has a complex bottom topography. The northern region is separated into two large basins of discontinuous sediment deposition by a rise of glacial sediments trending north from Thunder Bay. The inshore region of Lake Huron and the two escarpments are composed of glacial till and bedrock. The till is overstepped in the deeper water by glaciolacustrine clays which are themselves overstepped by postglacial muds. Postglacial mud accumulation is continuous in the southern basins due to the gentle relief of the lake bottom. In the northern region of the lake, mud accumulation is discontinuous due to the undulating nature of the lake bottom. Mud fills the hollows leaving glaciolacustrine clay exposed at the top of the undulations in this region.The surficial sediments contain variable amounts of quartz, clay minerals, organic carbon, and carbonates. Quartz content is greatest in the coarser inshore sediments while clay minerals and organic carbon are greatest in the liner offshore sediments. Carbonate is low throughout the lake, except along the eastern edge. Blite is the dominant clay mineral with lesser amounts of chlorite and kaolinite.Amphipods, oligochaetes, and chironomids are the major benthic organisms in the Huron sediments. Amphipods are most numerous at a water depth of 70 m, oligochaetes at 140 m, and chironomids in the shallowest depths.The textural characteristics of the sediments, defined by moment measures, can be interpreted as resulting from variable mixing of a clay and a sand end member population.Both end member populations are leptokurtic and asymmetrically skewed due to the introduction of a silt size mode predominantly in the form of a carbonate. The sand end member population is positively skewed and occurs in the inshore zone comprising the coastal nearshore region and the shallow mid-lake regions. The clay end member is negatively skewed and occurs in the depositional basins. Between these two extremes there is a gradual prograding from sand to clay related to a progressive mixing of the two populations. This mixing is believed to be a direct function of declining energy with increasing water depth.Sediment composition reflects both the source materials and the textural properties. The sediments of the southern basin are derived predominantly from glacial tills whereas the composition of the sediments of the northern basin has been substantially modified by dilution with reworked glaciolacustrine clays.

No abstract

Total mercury has been analysed in the surface 3 cm of sediment taken from 287 sample stations on an 8 km grid on Lake Ontario during 1968. The mercury distribution shows well-defined trends which can be related to sediment type; the concentration of mercury increasing from the shallow nearshore coarse sediments outwards, into the central, deep-water basin sediments composed of fine silty clays and clays. The average concentration of mercury in the nearshore sediments is 355 ppb, in the basin sediments 997 ppb and the average for the whole lake is 651 ppb. Regions of high mercury concentration (in the order of 2000 ppb) occur along the southern margin of the main lake basin and in the western (Niagara) basin of the lake. The dispersion pathways of these two regions point to the Niagara River as the prime source of mercury input to Lake Ontario. Most of this mercury is believed to be of industrial origin. An additional area of high mercury concentration with values up to 20 000 ppb, occurs at the eastern end of Lake Ontario (Kingston Basin) in the region of the lake close to the outlet to the St. Lawrence River. These high values in organic-rich, fine sediments are likely related to processes of biological concentration. The concentrations of mercury observed in the recent sediments of Lake Ontario can be accounted for by an average minimum daily input of 125 lb (56.7 kg) of mercury of which an estimated 42 lb (19.0 kg) is of natural origin and the remaining 83 lb (37.6 kg) is from industrial sources. The vertical distribution of mercury in a selected sediment core suggests that industrial mercury input commenced about the turn of the century, rose rapidly to circa 1943 and, since then, has shown a slow but continued rise to the time of core retrieval in 1970.

The chemical and physical characteristics of six cores from Lake Erie are described. The concentrations of Si, Al, K, Na, and Mg, which represent the major mineral species in the sediment, were uniform in each core. Surface enrichments of Hg, Pb, Zn, Cd, Cu, Organic-C, N, and P were observed at each location, due mainly to the increasing anthropogenic loading of these elements to the sediments since 1850. Concentration profiles for Mn, Fe, and S were related to sediment Eh and are due to mobilization of these elements in the pore waters.Natural and anthropogenic inputs of nutrients and heavy metals were calculated. About 60% of the total loading of these elements is being deposited in the Eastern basin. It is calculated that 30 million metric tons of fine-grained sediment accumulates in the offshore basins of the lake, each year. The major source of the sediment input is erosion of the shoreline bluffs, with the north shore between Erieau and Long Point contributing 21 million metric tons annually. A sediment mass balance suggests that a large part of this bluff material is transported up to 150 km and is deposited in the Eastern basin.