these biotopes are inhabited by a large variety of organisms, well adapted to
respective living condition and are composed by different species with predominance of early ontogenetic stages of invertebrate and fish.
In the same habitats accumulate many substances that are harmful for living
organisms, especially for early ontogenetic stages – eggs and larvae (Zaitsev 2008,
2012a, b; Zaitsev and Polikarpov 1964, 2002; Patin 1977). As a result of this, here
are forming the main hotspots and critical ecological zones in seas and oceans.
Contourobionts are the first organisms in the marine environment, contacting
with life-threatening factors and reacting to them by population size reduction up to
their complete disappearance in some areas, and in other ways, and signaling of this
to those whom it concerns. They got a figurative name of “Environmental sentinels”
and recommended as priority species for environmental monitoring facilities
(Zaitsev 2012a, b, 2015; Alexandrov and Zaitsev 2016).
In our practice of the Black Sea ecological monitoring, this methodological
approach proved to be much more effective, than the traditional one. Facts,
confirming the contour structure of seas and oceans, on the one hand specify
previous author’s ideas on life distribution in the marine environment and in
continental waters (Zaitsev 1986). On the other hand, they point necessity of a
new approach to assessment of the aquatic ecosystems’ state. Traditionally such
assessment of seas and oceans is carried out on the basis of survey of the whole
water column, by mean of allocation of hydrographic profiles and sampling at all
depths of the water thickness and bottom, although this is the most stable and
inalterable marine environment.
Along with the water column (pelagial) and the bottom (benthal), the contour, or
marginal biotopes are forming a very specific category of habitats in the marine
environment. Up to this day, the best studied among them is the aerocontour,
inhabited by neustonic organisms (Zaitsev 1971, 2012a, b).
Environmental processes in contour biotopes are developing according to the
other scenario, then in the water column. Modification of the habitat conditions here
leads to sharp decrease (or increase) of diversity and numbers of populations of
organisms, which all their life or at least early ontogenesis stages occur mainly or
exclusively in contour biotopes. Many of such species living in contour biotopes are
especially sensitive indicators of the marine ecosystem state. They were figuratively called “Environmental sentinels” (Zaitsev 2015).
The idea of the Environmental sentinels appeared at the author during the study
of changes in the ecosystem of the Black Sea. This inland sea is an excellent pilot
area for researches of the reaction of marine environment to different kinds of
man-made impacts. It is in the Black Sea, earlier than in other seas of Europe, have
been observed and investigated strong effects of eutrophication, anoxic events,
profound changes in species diversity, disappearance of populations of some native
522
Y.P. Zaitsev
respective living condition and are composed by different species with predominance of early ontogenetic stages of invertebrate and fish.
In the same habitats accumulate many substances that are harmful for living
organisms, especially for early ontogenetic stages – eggs and larvae (Zaitsev 2008,
2012a, b; Zaitsev and Polikarpov 1964, 2002; Patin 1977). As a result of this, here
are forming the main hotspots and critical ecological zones in seas and oceans.
Contourobionts are the first organisms in the marine environment, contacting
with life-threatening factors and reacting to them by population size reduction up to
their complete disappearance in some areas, and in other ways, and signaling of this
to those whom it concerns. They got a figurative name of “Environmental sentinels”
and recommended as priority species for environmental monitoring facilities
(Zaitsev 2012a, b, 2015; Alexandrov and Zaitsev 2016).
In our practice of the Black Sea ecological monitoring, this methodological
approach proved to be much more effective, than the traditional one. Facts,
confirming the contour structure of seas and oceans, on the one hand specify
previous author’s ideas on life distribution in the marine environment and in
continental waters (Zaitsev 1986). On the other hand, they point necessity of a
new approach to assessment of the aquatic ecosystems’ state. Traditionally such
assessment of seas and oceans is carried out on the basis of survey of the whole
water column, by mean of allocation of hydrographic profiles and sampling at all
depths of the water thickness and bottom, although this is the most stable and
inalterable marine environment.
Along with the water column (pelagial) and the bottom (benthal), the contour, or
marginal biotopes are forming a very specific category of habitats in the marine
environment. Up to this day, the best studied among them is the aerocontour,
inhabited by neustonic organisms (Zaitsev 1971, 2012a, b).
Environmental processes in contour biotopes are developing according to the
other scenario, then in the water column. Modification of the habitat conditions here
leads to sharp decrease (or increase) of diversity and numbers of populations of
organisms, which all their life or at least early ontogenesis stages occur mainly or
exclusively in contour biotopes. Many of such species living in contour biotopes are
especially sensitive indicators of the marine ecosystem state. They were figuratively called “Environmental sentinels” (Zaitsev 2015).
The idea of the Environmental sentinels appeared at the author during the study
of changes in the ecosystem of the Black Sea. This inland sea is an excellent pilot
area for researches of the reaction of marine environment to different kinds of
man-made impacts. It is in the Black Sea, earlier than in other seas of Europe, have
been observed and investigated strong effects of eutrophication, anoxic events,
profound changes in species diversity, disappearance of populations of some native
522
Y.P. Zaitsev