Climate Change: A Challenge for the Black Sea Biodiversity,

Requires International Cooperation

Victorita Radulescu

Department of Hydraulics, Hydraulic machinery and Environmental Engineering,

University Politehnica of Bucharest, Splaiul Independentei 313, Bucharest, Romania

Keywords: Biosphere, Biodiversity, Climate change, Environmental factors, Environmental economics, Marine safety.

Abstract: The Black Sea is a direct link between the European Union and Asia, being a complex geopolitical region.

Mutual respect through good neighborly treaties and continued cooperation are needed to achieve regional

environmental goals. This paper reflects the importance of ongoing cooperation in resolving new issues that

have arisen in recent decades. Coastal erosion followed by the collapse of rocks as a result of small

earthquakes in deep water, water pollution due to maritime accidents or municipal and industrial wastewater

discharges, eutrophication, pelagic fishing and climate change with thermal, chemical and biological changes

in the composition of seawater , these are just a few issues that need to be addressed. At the beginning of the

paper, some experimental measurements are briefly presented to highlight the current situation regarding the

sources of pollution. The high concentration of hydrocarbons and ions is the cause of the appearance and

overdevelopment of invasive marine species. A special paragraph illustrates in parallel some endangered

species and some invasive species. New rules on fisheries regulation need to be implemented. A healthy Black

Sea environment is a priority for the whole of Europe.

1 INTRODUCTION

The Black Sea, with an area of about 440,400 km

, is

considered a deep sea with a maximum depth of 2,212

m. Located between Europe and Asia it is surrounded

by the Pontic Mountains, the Caucasus and Crimea to

the south, east and north, the Strandzha Mountains to

the southwest and Dobrogea plateau in the northwest.

Romania, Bulgaria, Turkey, Ukraine, Russia and

Georgia are the countries bordering the Black Sea,

(EU Commission, Black Sea, 2018). Some large

rivers, such as the Danube, the Southern Bug, the

Dnieper, the Rioni and the Dniester, which flow here,

are the main source of fresh water (Black Sea

Commission, 2021). The Black Sea through the

Bosphorus Strait is connected to the Marmara Sea and

through the Dardanelles Strait to the Aegean Sea, the

Crete Sea and the Mediterranean Sea. On the opposite

side through the Kerch Strait is connected to the Sea

of Azov (EU Climate ADAPT, 2017).

In the last two decades, the Black Sea has faced

some unexpected problems caused either by natural

causes or by human interference. An increase in the

https://orcid.org/0000-0002-8707-1914

number of small earthquakes recorded in deep waters,

on the border between Romania and Bulgaria, has led

to the appearance of freshwater currents that locally

affect the composition of seawater. Additionally,

there was local erosion, followed by sand

deplacement and landslides of 2-3 m high shores in

the area of Mangalia, 2 Mai, and Vama Veche, and

even 10 m near Eforie Nord (Black Sea Diagnostic

Report, 2010). As a result, the beaches have shrunk

and the number of tourists has decreased, even in

normal years, but especially now during the

pandemic, when it is necessary to maintain social

distance.

Thus, new ecological problems have arisen due to

unsustainable development and inadequate

freshwater quality management in the main rivers

Danube and Dnieper (Zaitsev 2006). Wastewater and

solid waste discharged as a result of urban and

industrial activities, inadequate land management and

agricultural practices play a major role in the Black

Sea environment (

Boltachev, Karpova, and Danilyuk,

2006)

. They have direct consequences on surface and

groundwater pollution, eutrophication and

Radulescu, V.

Climate Change: A Challenge for the Black Sea Biodiversity, Requires International Cooperation.

DOI: 10.5220/0011105200003355

In Proceedings of the 1st International Joint Conference on Energy and Environmental Engineering (CoEEE 2021), pages 39-45

ISBN: 978-989-758-599-9

accelerated biodiversity degradation in the area

(

Dobrovolov, Ivanova, and Apostolu, 2003). Discharges

into the seawater of residual substances from urban

wastewater treatment plants of petroleum substances

from ports and shipyards or from shipwrecks have

also affected the quality of seawater (

O'Higgins,

Farmer and Daskalov, 2014).

Over the last decade, growing areas have been

affected, often leading to numerous fish and dead

jellyfish appearing on the surface of the sea,

associated with massive amounts of destroyed marine

vegetation. For example, in Romania, the beaches

were impossible to use in 2005 and 2007, in the

coastal area between Mamaia and Mangalia, for more

than three weeks in each case, even in the middle of

the summer season.

Finally, it should be noted that the Black Sea

region has become an area of interest for entire

Europe, representing the eastern border for the EU

and NATO, and a transit area for oil and gas resources

from Russia and the Caspian Sea. Due to its strategic

importance, the area has recently been subjected to

political tensions, as was the case in Crimea. The

Black Sea area is bordered by two EU member states,

Romania and Bulgaria, one candidate state-Turkey

and other non-EU countries. Consequently, each

country must abide by good neighborly and

environmental treaties in order to maintain the

regional balance and social prosperity of the Black

Sea countries, but mainly to restore the specific

biological balance (Black Sea, Ecolex Protocol,

1994).

2 ENVIRONMENTAL

MEASUREMENTS, WATER

CHARACTERISTICS

The Black Sea has distinct natural conditions. Over

90% of the deep water is anoxic, marked by the

absence of oxygen. It is the largest body of water in

Europe with a meromictic basin, without movements

and water exchanges between the lower and upper

layers of the sea. It is a rare phenomenon, hard to find

in other parts of the world. There is thus a

considerable difference in temperature between these

two layers. The lower oxygen deprivation layer is

inactive. The interaction between oxygen-rich surface

water and the deep zone is practically limited. This

stratified structure affects the diversity of Black Sea

organisms. Due to these natural factors, the diversity

of Black Sea fauna species is about three times less

than that of the Mediterranean Sea, making it

vulnerable to environmental disturbances affecting its

ecosystem.

In recent decades, sea currents have partially

changed their direction, pollution has steadily

increased, sandbanks have shifted, and the coastal

area is constantly changing. Thus, a modification in

the local balance of the marine bio-system has

occurred, leading to a slow but continuous

degradation. Interference between water layers

mainly affects the upper layer in which life exists,

disrupting the aquatic bio-system.

The Black Sea ecosystem is currently the subject

of intense discussion. Changes in its ecosystem over

the last 50 years clearly indicate its vulnerability to

anthropogenic effects. Black Sea marine resources

have declined due to overfishing, unplanned coastal

development and heavy maritime traffic. Due to the

economic interests of the whole of Europe, the Black

Sea Commission has been set up to monitor this area

on an ongoing basis. Examples of monitoring and

reporting are shown in Figure 1-a, b, c.

Figure 1: Monitoring reports: a-air currents, b-temperature

evolution, c- accidental algae bloom development.

According to international good neighborly

relations, a commission with international experts

from Bulgaria, Romania and Turkey, called CP-BSP,

the Commission for the Protection of the Black Sea

against Pollution, was set up in 2000. Its purpose is to

CoEEE 2021 - International Joint Conference on Energy and Environmental Engineering

systematically measure and create a database needed

to monitor this bio-system. Measurements are stored

and reported monthly, including temperature,

humidity, precipitation, wind speed and direction,

Figure 2-a, b, c.

Figure 2: Recorded measurements: a- temperature and

humidity, b- precipitations, c- wind velocity and direction.

In order to understand the changes, sand samples

were collected from the coastal area from different

depths, dates and places, considered important from

an economic and social point of view. Each sample

was subjected to optical and physical-chemical

measurements and analysis as mentioned below for

November 15, 2017 in the Mangalia area. Table 1

indicates the depth of sample collection: P1= 21-25

cm, P2= 54-78 cm, and P3= 160-200 cm in

percentages

Table 1: Characteristics of the sand in Romania coast.

Probes San

Silt Cla

P1 38.79 54.7 6.51

P2 30.6 58.9 10.5

P3 48.3 47.1 4.6

The measurements also consisted of biological,

physical and chemical tests performed in different

parts of the Black Sea. Until 2012, there was a steady

increase in eutrophication, more pronounced after

2009, when the naval accident off the coast of Turkey

was recorded. Recently, as a result of the

implemented measures, some positive signs have

been observed, but some problems still persist. At the

international level, a report by the Black Sea countries

highlighted the main factors of water pollution, listed

in Table 2. The main disturbance of the last two

decades was due to massive oil spills, especially in

1997, 2007 and 2009. They produced some chemical

and biological changes.

Table 2: Factors of water pollution.

Types of pollution

Sources of

ollution

Stationary

land-based

outfalls

River run-

off

Coastal diffuse

sources

Atmospheric

fall-out

Ships and

marine

latforms

Contamination with chemicals

- Nutrients and organic

matte

+ + + + +

- Oil and petroleum

roducts

+ + + + +

- Persistent organic

ollutants

+ + + + +

- Trace elements + + + + +

Radioactive

contamination

+ +

Marine litter (solid

waste pollution)

+ + + ? +

Biological pollution

- Microbial

contamination

+ + + +

- Introduction of

invasive s

ecies

+ + + +

Climate Change: A Challenge for the Black Sea Biodiversity, Requires International Cooperation

- Insufficiently treated or untreated industrial

liquid waste and sewage from coastal cities and

settlements;

- Inputs from agriculture, industry, mining and

municipal sewerage from the entire drainage area of

the Black Sea;

- Contributions from agriculture, animal

husbandry and unmanaged tourism, mainly through

land leaks (coastal rainwater effluents and

groundwater);

- Inputs from various sources of air pollution

(smoke, volcanic fumes, dust and exhaust fumes)

regardless of their place in the world, deposited on the

Black Sea water;

- Disposal of solid waste and dredged materials;

wastewater discharge and untreated ballast, oil spills,

lost fishing nets, introduction of new organisms due

to biofuel.

In 2018, according to the reports of the European

Environment Agency, the following chemical

composition was registered: Oxygen 0.8 -17.6 mg/l,

average value 6.96 mg/l, dissolved oxygen 5.36 -

10.28 mg/l , average value 7.66 mg/l, nitrates 0.03 -

7.40 mg/l, average value 1.25 mg/l, total organic

carbon 0.05-3.15 mg/l with average value 0.23 mg/l.

The maximum values of nitrates detected were

reached in 1997 and 2009. In the coastal waters of

Romania, in the period 2014-2018, there was a slight

decrease in nitrogen concentrations, due to the

decrease in fertilizer use in the last decade and the

application of the EU Directive. on Nitrates in the

Danube Basin.

Figure 3-a shows the amount of oil spilled in the

Black Sea in the period 1996-2010 as a result of

accidents or improper handling on shipyards, reported

by the EEA-European Environment Agency. Since

2002, satellite and more recently drone surveillance

of oil fields has been established. Figure 3-b shows

the oil spill following the accident off the coast of

Turkey in 2009. Oil spills cause eutrophication of the

Black Sea over time.

Figure 3: The main oil spills.

One of the most important consequences of

increased nutrient intake followed by eutrophication

of water is the disruption of its oxygenation regime,

usually followed by hypoxia and later anoxia. The

development of the hypoxia phenomenon, the

discharges of water from rivers with different hydro-

chemical and biological conditions are all correlated

with each other. As a result, the area with low oxygen

content in the water recorded in the Black Sea in the

N-V, after 2009 gradually expanded. Large areas

were covered with aquatic vegetation due to

eutrophication. In the worst case, the hypoxia and

mass mortality of plants in the N-V area of the Black

Sea could cover over 30-40 thousand km

Areas with hypoxia and anoxia are characterized

by abnormal sea conditions: temperatures of 15

vertical gradients of density of 6 conventional units,

salinity 6% at 1 m. A characteristic of nutrient

distribution is the absence of zero values in the

surface water layer. However, at the beginning of

summer 2016, the surface pH level reached 9.25

being oversaturated with oxygen, 170%. In the lower

layer, the pH level of the water dropped rapidly.

Consequently, there is an intense development of this

destructive process. The biochemical value of the

oxygen requirement reaches 2-4 mg/l, and the rate of

oxidation of organic matter exceeds 3-5 times the

average allowed value.

3 ECOSYSTEM PROBLEMS,

ENDANGERED AND INVASIVE

SPECIES

As the Black Sea eutrophicated, the number of

saprophytic bacterial plankton increased sharply,

especially in the type of cocci and bacilli, due to the

high level of dissolved organic matter. It represents a

source of nutrition for saprophytic microorganisms.

From the satellite can be seen the areas affected by

the excessive growth of small plankton, such as

Dinoflagellates, Cocolitophores and Euglenoids,

representing about 148 species and subspecies.

CoEEE 2021 - International Joint Conference on Energy and Environmental Engineering

Unfavorable conditions, such as strong solar

radiation in the summer of 2001, led to a massive

increase in algae (

Funda, Bat, and Sahin, 2019). Their

intensive development has increased the bio-

sedimentation of decaying plants, further leading to a

decrease in dissolved oxygen, reducing the

transparency of seawater, thus preventing the

penetration of light. Moreover, a drastic change in

zooplankton communities has been caused by the

outbreak of Cotylorhiza tuberculata, Cassiopea

Andromeda and the largest jellyfish in the Black Sea,

Rhizostoma pulmo and Aurelia aurita. Jellyfish with

a diameter of 1-1.5 m, non-existent 10-15 years ago,

were captured. All of these venomous species are

shown in Figure 4.

Figure 4: Invasive species of jellyfish.

In the Black Sea, there are about 200 species of

fish, over 500 species of mollusks, and macrophyte

aquatic plants (red, brown, blue, and green algae).

Of these, only about two dozen fish have economic

value, accounting for about 98% of catches in the

period 1996-2019. These include bud, anchovy,

Danube mackerel, turbot, cod, shark, lipac, mullet,

mackerel and three species of sturgeon (Acipenser

gueldenstaedtii, Acipenser stellatus and Huso huso).

Some of them are shown in Figure 5.

Figure 5: Specific species of fish: sturgeon, Danube

mackerel, mullet, tuna, Huso huso sturgeon.

All these changes in the composition of the

water caused the fish to move away from the

shore, thus increasing the number and size of

jellyfish. From this case, in 2016 the Romanian

sea fishing achieved one of the smallest

quantities recorded in the last 20 years.

The number of Pontic mackerel fish is

steadily declining. The main threat is the same as

in the case of sturgeon, the overfishing. Figure 6

shows images of endangered species. Other

species are also affected by the changes of

salinity and water quality, as example seahorses

and crabs due to eutrophication, angel sharks,

sturgeons and belugas due to pollution by oil,

European eel and hammerhead sharks due to

changing salinity.

Figure 6: Species of endangered fish: seahorse, angel shark,

dog shark, hammerhead shark, sea cat.

Among the endangered species may be also

mentioned Squatina (angel shark), Acipenser

gueldenstaedtii (sturgeon), Acipenser nudiventris

(visa), Acipenser persicus (Persian sturgeon),

Acipenser stellatus (trout), Acipenser sturuso

(sturgeon) Anguillael (anguillael), and the little guide

from the Danube Delta. The situation of the Danube

mackerel is better compared to sturgeons, due to its

natural abilities of faster recovery.

Climate Change: A Challenge for the Black Sea Biodiversity, Requires International Cooperation

4 GOOD NEIGHBOURHOOD

AND FISHING POLICIES

Romania and Bulgaria, as EU Member States, have

accepted and complied with all requirements

regarding the CFF- Catch Fish Fund and the total

allowable catches of mackerel and turbot. Fisheries

management has very different aspects in the

countries of the Black Sea region, with a certain

tradition of applying CFF quotas and fishing vessels

in the states of the former Soviet Union.

Turkey uses a different regulatory mechanism

without specifying FFC for the Black Sea. With the

exception of bilateral agreements, for example,

between Georgia, Turkey and Ukraine on fishing for

anchovy in Georgian waters, there is no general

agreement on the regional management of Black Sea

fish stocks.

In Russia, the 2007 CFF law provides for the

establishment of quotas, defined as "a scientifically

justified annual catch of aquatic biological resources

of certain species in a fishing zone". The quota can

vary greatly from year to year and is proposed by

certain fishing institutes (rybvods). In Ukraine, the

fishing quota has changed over the last decade,

mainly in terms of quota allocation.

In 2002, a new fishing system was introduced for

species such as anchovies and sprat, modeled after an

Olympic system, to be fished as long as CFF is

reached. Only valuable and rare species are regulated

by individual quotas. In Georgia, there is currently no

national fisheries policy governing certain fishing

quotas.

On the other hand, the Black Sea is a transit route

for oil and gas transportation. The risks associated

with these activities, and accidental pollution, are

expected to increase. About 50,000 ships sail through

the Bosphorus each year, of which about 10,000 are

oil tankers. Several Black Sea ports in Russia and

Georgia are terminals for Caspian oil and gas

pipelines. Although it brings jobs and economic

development, the increase in oil transport, transit and

handling operations, if not systematically regulated

and monitored, could put additional pressure on the

region's ecosystem.

5 CONCLUSIONS

The Black Sea Commitment provides a regional

framework for cooperation to protect the area from

pollution. Following the accession of Romania and

Bulgaria to the EU, the Black Sea has become the

focus of various EU fisheries policies and integrated

coastal zone management.

Even if it is considered the ecological changes due

to environmental factors such as the low level of

oxygen content in the water, the water temperature

and its pollution, the main factor that continues to

affect the fish population is in fact overfishing. The

fish stock has deteriorated dramatically over the last

three decades. Local human communities, which are

heavily dependent on fishing, are clearly affected.

In contrast, the diversity of commercially caught

fish has declined during this period from about 26

species 20-30 years ago to six in the main, while the

volume of fish caught has steadily increased. This

represents a larger volume of specific fish species

existing in the Black Sea, but not a sustainable

development of the variation of the species caught.

This is almost entirely caused by the significant

amount of anchovy fishing carried out by 2 states,

accounting for almost 80% of the total catches of this

species in the Black Sea.

Illegal fishing in the Black Sea is growing rapidly,

with the development of remote sensing systems

affecting both marine biodiversity and economic

activities in the region.

In 2015, all riparian countries adopted an updated

BS-SAP Strategic Action Plan for the rehabilitation

and protection of the Black Sea. Based on a coherent

approach, the plan aims to address cross-border

environmental issues. It contains realistic objectives,

including legal and institutional reforms, as well as

suggestions for the investments needed to address key

environmental issues.

A number of projects developed by international

teams have restored some environmental issues. The

number of algae is declining, with Mnemiopsis leidyi,

biomass being less common. It was reduced after the

invasion of Beroye ovata, which feeds on this

destructive species of algae. The abundance of forage

zooplankton is increasing, followed by an increase in

small pelagic fish.

National efforts and international cooperation

within BS-SAP have shown the first signs of recovery

in the Black Sea ecosystem.

It is also recommended to adopt a unitary policy

on the quality of wastewater that can be discharged

into the Black Sea.

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Climate Change: A Challenge for the Black Sea Biodiversity, Requires International Cooperation