Aquatic chemistry is becoming both a rewarding and substantial area of inquiry and is drawing many prominent scientists to its fold. Its literature has changed from a compilation of compositional tables to studies of the chemical reactions occurring within the aquatic environments. But more than this is the recognition that human society in part is determining the nature of aquatic systems. Since rivers deliver to the world ocean most of its dissolved and particulate components, the interactions of these two sets of waters determine the vitality of our coastal waters. This significant vol ume provides not only an introduction to the dynamics of aquatic chem istries but also identifies those materials that jeopardize the resources of both the marine and fluvial domains. Its very title provides its emphasis but clearly not its breadth in considering natural processes. The book will be of great value to those environmental scientists who are dedicated to keeping the resources of the hydrosphere renewable. As the size of the world population becomes larger in the near future and as the uses of materials and energy show parallel increases, the rivers and oceans must be considered as a resource to accept some of the wastes of society. The ability of these waters and the sediments below them to accommodate wastes must be assessed continually. The key questions relate to the capacities of aqueous systems to carry one or more pollutants."

Metal pollution in the aquatic environment

Copper compounds have been widely used in industrial processes and agriculture. As a result, elevated Cu concentrations can be found in certain areas of the biosphere. To better understand the toxicity of Cu to organisms it is necessary to understand the mechanism by which Cu influences biological and chemical processes in the environment. This review will examine Cu toxicity, microbial resistance mechanisms and factors influencing Cu speciation and toxicity in the environment

Copper toxicity and chemistry in the environment: a review

The environmental and microbiological factors that can influence heavy metal toxicity are discussed with a view to understanding the mechanisms of microbial metal tolerance. It is apparent that metal toxicity can be heavily influenced by environmental conditions. Binding of metals to organic materials, precipitation, complexation, and ionic interactions are all important phenomena that must be considered carefully in laboratory and field studies. It is also obvious that microbes possess a range of tolerance mechanisms, most featuring some kind of detoxification. Many of these detoxification mechanisms occur widely in the microbial world and are not only specific to microbes growing in metal-contaminated environments.

Microorganisms and Heavy Metal Toxicity

Culture experiments with the estuarine diatom Thalassiosira pseudonana (clone 3H) in highly chelated seawater media demonstrate that growth rate inhibition and copper content of cells are related to cupric ion activity, and not to total copper concentration. Cupric ion activity was altered independently of total copper concentration by varying the chelator concentration, and the pH. Cellular copper content (moles/ cell) of 3 to 4 day old cultures followed a hyperbolic relation with cupric ion activity: 4.8 X 10• Gou Cu/cell = acu + 10 0.2 where a ou is the cupric ion activity. Copper inhibited growth rate at activities above 3 X 10-u M and growth ceased at values above 5 X 10--0 M; however, the relation between growth rate inhibition and cupric ion activity was not a simple hyperbolic function. In experiments with the estuarine green alga Nannochloris atomus (clone GSB nanno), growth rate inhibition also was related to cupric ion activity with partial growth rate inhibition occuring in the activity range 4 X 10-u to 2 X 10--0 M. Calculated estimates of cupric ion activity in seawater indicate that natural activity levels can be inhibitory to these phytoplankton depending on pH and the degree of copper complexation by natural organic ligands.

The relationship between cupric ion activity and the toxicity of copper to phytoplankton [Thalassiosira pseudonana, Nannochloris atomus, Algae]

We present an overview of the oceanic chemistries of the bioactive trace metals, Mn, Fe, Co, Ni, Cu, and Zn; we combine field data with results from laboratory phytoplankton culture-trace metal studies and speculate on the potential influences of these trace metals on oceanic plankton production and species composition. Most field studies have focused on the effects of single metals. However, we propose that synergistic and antagonistic interactions between multiple trace metals could be very important in the oceans. Trace metal antagonisms that may prove particularly important are those between Cu and the potential biolimiting metals Fe, Mn, and Zn. These antagonistic interactions could have the greatest influence on biological productivity in areas of the open ocean isolated from terrestrial inputs, such as the remote high nutrient regions of the Pacific and Antarctic Oceans. The emerging picture of trace metal-biota interactions in these oceanic areas is one in which biology strongly influences distribution and chemical speciation of all these bioactive trace metals. It also seems likely that many of these bioactive trace metals and their speciation may influence levels of primary productivity, species composition, and trophic structure. Future investigations should give more complete consideration to the interactive effects of biologically important trace metals.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1991.36.8.1555

Interactive influences of bioactive trace metals on biological production in oceanic waters

Copper in ionic form is found to be very poisonous for photosynthesis and growth of unicellular algae at concentrations of Cu usually found in natural waters. This indicates that Cu is ordinarily not present in ionic form but is complexed by organic matter such as polypeptides. The affinity of Cu to diethyl-dithiocarbaminate is very much higher than to the organic matter which complexes Cu in nature. Thus, it is not possible to distinguish the two forms of Cu during analysis. Complexed Cu is not poisonous to algae. It has recently been shown that ocean water in the centres of upwelling becomes suitable for plankton growth only after the addition of a chelator. This suggests that a large part of the Cu found in the subsurface waters of the oceans is present in ionic form. Some manufactures of C14 ampoules have used ordinary distilled water which often has a content of about 250 μg Cu/l. Thus, it is very likely that some productivity measurements have been influenced. A likely example is mentioned.

Copper ions as poison in the sea and in freshwater

Influence of Deleterious Concentrations of Copper on the Growth of Chlorella pyrenoidosa

On the Maximum Quantity of Plankton Chlorophyll per Surface Unit of a Lake or the Sea

Employing a special batch technique which involves extremely low concentrations of the alga Selenastrum capricornutum, it is shown that a growth rate of ca. 75% of optimum growth occurs at a concentration of 0.02 μg-at N(NH4+) l-1. The low concentrations of this N-source in the oligotrophic parts of the oceans (ca. 0.06 μg-at l-1) thus give rise to a borderline deficiency. As the half-saturation constant (KS) for growth was recorded at 0.05 μg-at N(NO3-), this ion can hardly be of much importance at the low concentrations present in these parts of the oceans. It is wrong to assert that N is the primary limiting nutrient. Phosphate also is found at concentrations giving rise to a borderline deficiency.

E. Steemann Nielsen

Papers

Copper ions as poison in the sea and in freshwater

Influence of Deleterious Concentrations of Copper on the Growth of Chlorella pyrenoidosa

On the Maximum Quantity of Plankton Chlorophyll per Surface Unit of a Lake or the Sea

Growth of plankton algae as a function of N-concentration, measured by means of batch technique

How to Measure the Illumination Rate when Investigating the Rate of Photosynthesis of Unicellular Algae under Various Light Conditions