🌊🧪 Thus, unlike the aragonite preservation event which appears as a discrete layer within the sediment, the calcite preservation event would be largely homogenized throughout the upper eight or so centimeters of sediment. It would give every appearance that calcite accumulation had commenced

🌊🧪 As biologically active constituents pass through the ocean, they participate in its internal cycles. Warm surface waters receive their supply of dissolved constituents from two sources: river water and water from the deep ocean, which exchanges with surface water. If the concentration of a

🌊🧪 For an analogy to this situation, consider a group of space pioneers living on a large glacier covering the polar region of a distant planet. After realizing the futility of shoveling aside the ever accumulating snow, these colonialists reconcile themselves to lifting their bodies and

🌊🧪 After 1000 years of continuous habitation with a steady population of 10,000, their resident archeologist, out of shear boredom, digs a deep trench in an attempt to find relics of their arrival. Finally, when his trench has reached a depth of 300 meters, he succeeds. - Broecker and Peng

🌊🧪 The results of such a study (221) are consistent with the prediction made from the mean age of surface nodules and the mean accumulation rate of the sediment. The number of nodules in a sediment layer several meters thick is about the same as the number of nodules on the surface! -

🌊🧪 Roughly 90 percent of the carbon will remain in dissolved form. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 So-called authigenic minerals in sediments are formed by spontaneous crystallization within the sediment or water column. They make up only a small fraction of the total sediment. The most important of these is the iron-manganese oxide material in sediments formed through the reduction of

🌊🧪 In words, a typical P atom, upon release to solution from some sedimentary or metamorphic rock by erosion, is carried by rivers to the sea. It then goes through an average of 100 oceanic mixing cycles: 100 times surface-dwelling organisms fix it into a particle that sinks and is destroyed

🌊🧪 HORIZONTAL SEGREGATION OF CONSTITUENTS IN THE DEEP SEA - The simple two-box model of ocean chemistry has permitted us to describe in a quantitative manner the primary features of the marine chemistry for biologically utilized constituents. In the real world, the concentration of a given

🌊🧪 As in most chemical plants, the two critical features of the ocean are the manner in which the ingredients are mixed and the manner in which the ingredients react with one another. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 By the time the components of their debris are returned to the ionic form as a result of tissue oxidation or hard part solution, downward movement under the influence of gravity or migrating animals has occurred. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Many components of sea salt show little variation in concentration within the sea. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 All plants and animals produce organic tissue. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 For every atom of P in the deep ocean there are about 50 atoms of Si. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 The difference between the enrichment of these biologically active constituents in the deep Pacific and in the deep Atlantic depends on the deep water circulation pattern in the world ocean. About half the water being fed into the deep ocean is generated at the northern end of the Atlantic

🌊🧪 The chemical composition of the organic soft tissue formed by plants is thought to be relatively constant: for every atom of P in this tissue there are on the average about 15 atoms of N and on the average 105 atoms of C. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Plants live only in surface waters, from which they extract certain constituents needed to construct their tissues. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Animal tissue has roughly the same P/N/C ratio as plants. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 The amount of all the dissolved gases in surface ocean water is controlled by their concentrations in the overlying atmosphere and by temperature. The task of establishing these surface ocean concentrations is simplified by the fact that the atmosphere is almost perfectly mixed with regard

🌊🧪 Thus, at this point, the worms appear to have the upper hand. If each year worm nudges were to lift a nodule 3 microns, then in a million years it would be raised by the required 3 meters! Unfortunately, we have no worm nudge tracers. So the puzzle remains an annoyance to those who study

🌊🧪 Roughly 90 percent of the carbon will remain in dissolved form. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 This task would be extremely complex if the composition of sea salt were more varied. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 As the papers on each topic are listed in order of publication date and as they are annotated with a sentence or two stating their contribution, the reader can get some sense of development of the data base and thinking in a given area by looking through this reference list. Hence, the

🌊🧪 The movement of the ocean floor will often carry a segment of the crust across the equator (see Figure 2-28). Since opal deposition today is very rapid along the equator in the Pacific Ocean, we would expect to find a silica rich horizon in the sedimentary record of any crustal segment

🌊🧪 Let us imagine what would happen if a 6 cm thick layer of calcite were deposited during Holocene time on the top of glacial red clay. Through the action of the worms living within the sediment this calcite would be thoroughly mixed with the red clay deposited during late glacial time and

🌊🧪 The temporary entrapments in particulate matter experienced by these wandering ions will prove of particular interest to us. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Hard parts made of SiO2 are produced by diatoms (plants) and radiolarians (animals). - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Carbon is also used by organisms to construct their calcium carbonate hard parts. In CaCO3 there is one C atom for every Ca atom. In sea water there are 20 C atoms for every 100 Ca atoms. Thus, the generation of CaCO3 depletes carbon about five times more rapidly than it does calcium. -

🌊🧪 Before interpreting this record, it must be pointed out that other workers have not been so successful in finding trees that give smooth records. Stuiver of the University of Washington has studied solitary trees from sites along the west coast of the Americas and Francey of Australia has

🌊🧪 Having made note of the artifacts of his forefathers' arrival, he ponders the number of bodies he uncovered during his digging. He correctly calculates that, as his trench covers 0.1% of the area of the colony, 10 people should on an average be living within its bounds at any one time. The

🌊🧪 The biogenic component of sediment consists mainly of two substances that are produced as hard parts of organisms. These are calcite and opal, precipitated by plankton living in the waters of the surface ocean. As mentioned in Chapter 1, calcite is formed by coccoliths (plants) and by

🌊🧪 OPAL SOLUTION ON THE SEA FLOOR - The ocean is everywhere undersaturated with respect to the mineral phase opal. Thus, once formed, the hard parts of diatoms are immediately subject to solution. As can be seen from the sediment trap data in Table 1-3, there is no marked decrease in the

🌊🧪 His third day was analogous to the more usual situation in the deep sea, where far more non-opal than opal fragments fall. In this case, his retrieval rate decreased greatly due to the competition by non-oak leaves for his attention. Furthermore, the more oak leaves he did retrieve, the

🌊🧪 The volume of the warm reservoir (plus one half of the main thermocline) is only about one-tenth that of the cold reservoir (plus the other half of the thermocline). As water resides in the cold reservoir for 1000 years, it must reside in the warm reservoir for about 100 years. Since the

🌊🧪 An analogy will help to clarify this situation. A botanist receives a grant to study the process of 'leaf detachment.' He hires a research assistant and takes him off to a nearby experimental forest where he has marked off several study plots. The assistant is instructed to begin each day

🌊🧪 As shown in Figure 9-7 by comparing the results on all these cores it is possible to roughly determine how far the lysocline for aragonite dropped during the preservation event. As can be seen from this figure the drop was quite large (i.e., about 2 kilometers). - Broecker and Peng (1982),

🌊🧪 If the amount of nitrate in the sea were to drop below the amount required to maintain this ratio, then species which are capable of fixing molecular nitrogen would gain an advantage and would begin to produce nitrate faster than it was being destroyed within the sea. - Broecker and Peng

🌊🧪 Those for other of the elements dealt with here are listed in table 4-15. As can be seen, there is some similarity between the order of these constants and the removal times of elements from the sea. Manganese, however, is so far out of order that one wonder's how applicable these

🌊🧪 Together they add up to a total of six times more carbon than is now in the air! The greater part of this is coal. Thus the future CO2 levels in the air depend very much on the extent to which we utilize these coal reserves. However, it must be kept in mind that even if we were to burn

🌊🧪 When a batch of typical deep Pacific water returns to the surface, plants extract phosphate and nitrate until both of these constituents have been depleted. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Oceanic mixing is accomplished by a complex system of currents and a host of turbulent eddies. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 The differences in the vertical and horizontal distributions of these constituents are the result of differences in the depth to which the various particulate phases fall before being returned to solution. Some of these species are totally depleted in warm surface water; others are only

🌊🧪 Sodium, for example, is both abundant in the dissolved matter in rivers and sparingly reactive in the sea. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 Of this some is rejected in fecal pellets which fall toward the sea floor. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 A decade has passed since Chemical Oceanography, the predecessor to this book, was written. During this time our knowledge of the chemistry of the oceans has mushroomed. The Geochemical Ocean Sections program (GEOSECS) fleshed out our sketchy picture of the distributions of chemical,

🌊🧪 For studies in the open ocean, this relationship can be simplified. The calcium content of seawater is nearly constant; it varies with respect to the salt matrix only by about 0.5 percent and, as a result of salinity differences, by only another percent or two. Since the variations in

🌊🧪 So also do sediments nearly free of both of these phases. The abundance of these phases at any point on the sea floor reflects both their rate of production in the overlying water column and the extent to which they are subjected to solution on the sea floor. Since both the rate of

🌊🧪 Then another trip through the sea begins. - Broecker and Peng (1982), Tracers in the Sea

🌊🧪 The depth dependence of the calcite content of sediments from various regions of the ocean is shown in Figure 2-7. As can be seen, the boundary between sediments with well-preserved calcite and sediments free of calcite is not sharp. A zone of gradation in the extent of calcite dissolution

🌊🧪 As proposed by Emerson of the University of Washington and Bender of the University of Rhode Island there is another way in which the solution process for calcite differs from that for opal. If organic material raining to the sea floor is stirred into the sediment column before being eaten