4.2.1 Distribution of Indicator Groups of Marine 

 Heterotrophic Microorganisms 



ALLA V. TSYBAN, GENNADIY V. PANOV, and SVETLANA P. BARINOVA 



Natural Environment and Climate Monitoring Laboratory and Academy of Sciences, Moscow. USSR 



Introduction 



Over the last few decades, the attention over ocean pollution 

 has become one of the most urgent problems in applied 

 oceanography and is drawing great attention by world scientific 

 communities (Goldberg, 1970; Bemhard & Zattera, 1975; 

 Izrael & Tsyban, 1981, 1985a, 1989; Pravdic, 1981; Gesamp, 

 1982; Kullenberg, 1984). Today's anthropogenic impact on 

 the World Ocean creates a tense ecological situation. Pollutants 

 are becoming not only a continuously active ecological factor 

 (Izrael & Tsyban, 1985), but also an evolution factor by 

 affecting sea organisms (Izrael & Tsyban, 1989). Pollutants 

 getting into the sea environment, including xenobiotics, cause 

 rapid change in sea organisms and, due to directional selection, 

 result in active growth of certain hydrobionts and disappearance 

 of others that are not able to tolerate the action of foreign 

 substances. Organisms, which have adapted to new chemical 

 compounds that pollute the sea environment and then take a 

 dominant position in the biocenosis structure, are named after 

 the chemical substance. There are grounds to suggest that the 

 development of these hydrobionts is a function biological 

 response to the chemical pollutants of the world's oceans 

 (Izrael & Tsyban, 1981, 1985a, 1989). Biological significance 

 of indicator types is determined by their special designation. 

 Some fill a critical gap in biocenoses, others help to restore the 

 natural backgrounds while still others determine the immunity 

 of the sea ecosystem (Izrael & Tsyban, 1989). The latter 

 include sea microorganisms. 



Microorganisms have high rates of reproduction and 

 extensive range of constitutive and inductive enzymatic activity. 

 The latter characteristic stipulates their ability to transform and 

 utilize practically all naturally occurring organic compounds. 

 For this reason, these organisms are distinguished for their 

 unique ability to rapidly adapt to changing environmental 

 conditions. For example, an accidental oil spill in the world's 

 oceans would result in rapid and abrupt increase of hydrocarbon 

 oxidizing bacteria by 3-5 orders of magnitude (Gunkel, 1968; 

 Atlas el ai, 1976; Le Petet et ai. \911: Oppenheimer et ai. 

 1977; Atlas, 1981). 



The possibility of using microorganisms that are capable 

 of oxidizing oil as indices of the degree of hydrocarbon 

 oxidation under natural conditions and indicators of oil pollution 

 was shown in the 1950's (Izjurova, 1950; Voroshilova & 

 Dianova, 1950. 1952). According to Voroshilova and Dianova 

 (1950, 1952), the number of oil-oxidizing bacteria in clean 

 pools did not exceed 1 00 cells/ml, and in 50% of the cases, less 

 than 10 cells/ml. Another parameter used as an index of the 

 degree of water pollution with oil products is the ratio of the 



numbers of oil-oxidizing to heterotrophic bacteria (Voroshilova 

 & Dianova, 1950; Gavrishova, 1969; Mironov, 1970). Atlas 

 (1981) used the ratio between oil oxidizing microorganisms 

 and total bacterial number as an index of oil pollution. 



The concept of using microbes as indicative of organic 

 pollutants in the World Ocean has been most actively developed 

 during the last 20 years. Itwas shown (Tsyban ef a/., 1985)that, 

 depending on the phenomena under consideration, microbial 

 cenoses may act not only as indicators of physicochemical and 

 biological processes but also as a powerful biotic factor, 

 facilitating pollutants' elimination from the sea environment. 



At present, physiological and biochemical potential of 

 microbial populations is at the stage of active developments. 

 However, these important fields of marine microbiology have 

 not investigated the distribution in different parts of the World 

 Ocean or with depth of heterotrophic bacteria using or 

 transforming various organic substances. Bacteria using high- 

 molecular toxic compounds (e.g., benzo(a)pyrene [BaP] and 

 polychlorinated biphenyls [PCB's]), are an important 

 characteristic of the world ecosystems state under the conditions 

 of increasing anthropogenic influence. 



Materials & Methods 



Investigations of indicator microflora in the Bering Sea 

 began in 1981 (Izrael et al., 1987) and continued during the 

 period of the Second Joint US-USSR Expedition on board the 

 research vessel (WW ) Akademik Korolev in 1984 (Izrael etai, 

 1988; 1989; 1990). These investigations were continued in 

 1 988 during the Third Joint US-USSR Bering & Chukchi Seas 

 Expedition on the Akademik Korolev. It should be noted that 

 in 1 988 observations were carried out not only in the same areas 

 of the Bering Sea as in 1981 and 1984 but also covered some 

 new areas: the Gulf of Anadyr, the Chirikov basin, the Bering 

 Strait, and the southern part of the Chukchi Sea. All together, 

 82 stations were studied in the Bering Sea and 3 1 stations in the 

 Chukchi Sea. 



Water samples from the near-surface microlayer 0-2 cm 

 thick were taken with sterile water microsamplers, with sterile 

 bottles, or with plastic Niskin Water samplers, presterilized 

 with 96% ethanol. These samples were immediately analyzed 

 to reveal indicator bacteria, including the following forms: 

 saprophytic bacteria (SB), hexadecane oxidizers (HDB), 

 benzo( a)pyrene transformers ( BaPB ), and polychlorobiphenyl 

 transformers ( PCB B ). The detennination of bacterial indicator 

 groups is viewed as a study of physiological activity of 

 indigenous sea microflora prior to their isolation from the 

 habitat. 



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