TERRESTRIAL ECOLOGY
ARIZONA STATE UNIVERSITY
ABS 370 - ECOLOGY
SPRING 2024
A.
ENVIRONMENT LAND
Terrestrial ecology is one of the most complex and diverse ecological sciences. Land is
usually highly variable in both time and geography across three major environments. Of
particular interest in studying ecology in terrestrial environments is the emphasis on
population and community organization and autogenic developmental processes such as
ecological succession. In this chapter we will discuss the composition and geographic
variation of terrestrial communities, noting some special metabolic properties of interest in
terrestrial ecosystems. The differences between terrestrial and aquatic habitats are as follows:
1.
On land, moisture is the limiting factor; terrestrial organisms are always faced with
the problem of drought. Evaporation and transpiration are unique processes of energy
loss in terrestrial environments.
2.
Temperature variations and temperature extremes are more in air than water media.
3.
The rapid circulation of air at the Earth's surface will result in a constant content-mix
of O2 and CO2.
4.
Although soil is a solid buffer rather than air, a strong framework has developed in the
soil, namely plants and animals, which have recently taken on a special significance
for development.
5.
Land is unlike the ever-contacting ocean where land is the most important
geographical barrier to its free movement.
6.
As a natural substrate, although the most important is in water, the most specialized is
in the terrestrial environment. Soil is the largest source of various nutrients (nitrate,
phosphorus, etc.) that constitute a major development of the ecological subsystem.)
In summary, climate, which consists of temperature, humidity, light, etc., and substrate,
which consists of physiography, soil, etc., are two groups of factors that interact with
populations in determining land communities and ecosystems in nature.
B.
TERRESTRIAL AND REGIONAL BIOTA BIOGEOGRAPHY
What is interesting about the evolution that took place on land is the development of
taxonomic categories to higher levels of the plant and animal world. Thus, the complexity
and specialization of all organisms, namely seed plants, insects, and warm-blooded
vertebrates, which have hitherto dominated the land, has increased. The latter includes the
development of the human population, which over the years has had a profound effect on the
environment biosphere and especially in terrestrial ecosystems. This does not mean that
lower-level forms such as fungi, bacteria, protozoa, and so on are absent or unimportant;
microorganisms play equally important roles throughout the ecosystem. Although humans
and their associates (plants, domestic animals, rodents, fleas, and pathogenic bacteria)
provide a wide distribution across the face of the earth, each land area tends to have its own
specialization of flora and fauna.
Islands often differ greatly from their mainland counterparts. The interesting thing
about their biogeography is their special relationship to the land revolution. Alfred Russel
Wallace together with Darwin wrote one of the first questions of natural selection that almost
came true and was the first attempt at a regional system of biogeography. The floral world as
viewed on a plant map is very similar to the faunal regions on an animal map.
The difference is the recognition of the Cape region of Southern Africa as a separate
large region. This small area of the southern African Union still has an extraordinarily rich
flora of more than 1500 genera, of which 500 (30%) are endemics found nowhere else. Many
unique (interesting) species are widely cultivated in European gardens. Australia and South
America are also endemic to a large number of species. Organisms that occupy ecologically
similar communities found in regions with different biogeography are known as Ecological
equivalent, even though they are not closely related taxonomically. For example, the cacti
(family Cactaceae) that are prominent in the desert regions of the new world (especially the
neotropical regions) are very complete. But in the deserts of Africa, species of Euphorbiaceae
appear to be cacti that have developed thorn-like and succulent forms. Exceptional examples
similar to this are also found in the animal kingdom.
It is not always the terrestrial environment in such communities that produces
different species, as in almost every ecology, humans intentionally or unintentionally modify
the distribution of plants, often introducing the wrong species. Islands separated from the
mainland almost entirely provide species that are endemic to introduced varieties, for
example many song birds are partially housed in Hawaii.
C.
GENERAL STRUCTURE OF TERRESTRIAL COMMUNITIES
Terrestrial organisms are so varied that classifications based on life form and place of
life as in benthos- plankton-nekton are impractical.
A basic tropical classification for biotic studies can be used in terrestrial communities,
namely a general classification based on the main food of nicia, which consists of autotrophs
and heterotrophs.
1.
Autotroph
A prominent feature of terrestrial communities is the presence and dominance of a large
number of green plant roots that are not only. Although there are algae in the soil, they play a
lesser role than phytoplankton in aquatic environments. Land plants, however, depend on
microorganisms for their food, for example the mychoriza symbiosis.
Vegetation is a general term used for all plants found in a place with all their
characteristic properties, generally classified and called land communities.
Some terrestrial organisms can adapt to almost any situation. A series of terms
herbaceous and woody or tree, shrub, grass, and forb (including herbaceous open grasses, i.e.
leguminoceae), are commonly used and form the basis of distributional designations for the
recognition of major terrestrial communities. Other terms that adapt to the environment are
known as hydrophytes (adaptation to wet environments), mesophytes (moist environments),
zerophytes (dry environments), and halophytes (salt environments).
A commonly used classification is the classification of living forms recognized by
Raunkaier (1934), which is based on the elongation of organ buds, consisting of six main
categories, namely:
1.
Epiphyte. Aerial plants, their roots are not deep in the soil.
2.
Phanerophyte. Aerial plant, bud extension perpendicular to the stem. Five subgroups
fall under this category: trees, shrubs, succulent stems, herbs, vines.
3.
Chamaefit. Surface plant, extension of the buds on the surface of the soil.
4.
Hemi-cryptophyte. Shrubby plants, buds at or slightly below ground level.
5.
Cryptophytes or Geophytes. In-ground plants, the buds are in the soil in the form of
tubers or rhizomes.
6.
Therophytes. Annuals, where the complete life cycle from seed is in one vegetative
period, if the season is unfavorable will survive in seed form.
In most of the series shown, one aim is to increase adaptation to adverse temperature and
humidity conditions. The main species in tropical rainforests consist of Phanerophytes and
Epiphytes, whereas in northern forests, a high proportion consists of protected life forms. The
flora of the extreme desert and alpine regions are annuals. According to Chain (1950) in the
study of local conditions, care must be taken in assuming the proportion of species of
different categories as an indicator of climate, because edaphic factors and successional
stages have a great influence on the composition of life forms.
2.
Phagotrophic (Macro Consumer)
In conjunction with the large amounts of nicia provided by vegetation, terrestrial
communities have an array of animal consumers with extreme variation. The first consumers
are not only small organisms such as insects, but also include very large herbivores such as
hoofed mammals. The latter are unique to terrestrial communities and have little parallel with
aquatic communities (e.g. turtles eating large plants). Terrestrial grazers differ greatly in
structure and size from grazers in aquatic conutas, such as zooplankton. Because terrestrial
autotrophs produce a lot of low-utility food (cellulose, lignin, etc.), detritivores are very
prominent in terrestrial communities.
The type and abundance of insects and other arthropods is another important feature of
terrestrial communities. The study of insect ecology has attracted much attention. With the
discovery of DDT, the entomology laboratory moved into the chemistry laboratory. Attention
to biological control of insects was reinvigorated, so entomology departments worked closely
with ecologists and field studies became popular again.
3.
Saprothophic (Micro Consumer)
Organisms that mineralize organic matter and form functional values from it in the
terrestrial environment are not decomposer microorganisms include not only bacteria and
fungi, but also protozoa and other small animals. Decomposer microorganisms can be divided
into four taxonomies, namely :
1.
Fungi, including yeast and mold.
2.
Heterotrophic bacteria, including those that form and do not form spores.
3.
Actinomycetes, whip- or thread-shaped, bacteria that have certain morphological
characteristics like fungi.
4.
Soil protozoa, including amoeba, cilliata, and especially colorless flagellates.
These decomposers are found in terrestrial communities, but are mainly concentrated
in the topsoil (including litter). Decomposition of plant debris, of which a large proportion
occurs in respiration communities in many terrestrial ecosystems, involves a range of
microorganisms such as the following:
The first two groups use more easily decomposed organic substances such as simple
sugars, amino acids and proteins. Then cellulose bacteria work on stronger compounds and
Actinomycetes form humus, which is the final production of the second stage of
decomposition (the first stage is particle/detritus formation). The process is known as
humification. The third stage of decomposition is called humus mineralization, in cold areas
the process will be very slow and will be faster in hot areas or if the soil is exposed to air
during ploughing.
The role of soil protozoa is widely known, only a few important roles are recognized.
Protozoa (cilliata) are preyed upon by bacteria resulting in faster decomposition as they
stimulate the growth and metabolism of predators, where wood (lignin) is eaten by a
somewhat different set of organisms than those shown above. Fungi play a similarly
important role in the decomposition of lignin.
There are no good indicators of the number or biomass of microorganisms that can
influence their activity or speed of activity. The number of decomposer microbes ranges from
1012 - 1015 per m2 and the biomass is approximately 1-103 grams (dry matter)/m2 in
productive terrestrial ecosystems (in pastures and other areas, where the environment is the
limiting factor, it is even smaller).
Temperature and water are very important in stimulating decomposer activity,
because on land these factors are more variable than in aquatic habitats so it is easy to see
why decomposition on land often occurs sporadically. For example, many bacteria and fungi
require a microenvironment with a higher moisture content than is required by the roots of
higher plants, consequently in areas with long dry periods (or long cold periods), Annual
production in an ecosystem often greatly exceeds annual decomposition, in even climax
vegetation.
Periodic fires in such situations work as a decompose,r, transforming accumulations
of litter or dead wood. Complete fire control in ecosystems such as California's forests is
unlikely to attract human or ecosystem attention. Periodic fires will aid the work of microbial
decomposers in preventing large fires that can set back succession too far and destroy human
property.
The two major strata that comprise all complete ecosystems, autotrophic and
heterotrophic, are well characterized in terrestrial environments. Vegetation and soil are the
commonly recognized words for these two layers in terrestrial ecosystems. And each sub-
system is described as follows starting from soil.
D.
SOIL SUBSYSTEM
Soil structural communities and their metabolisms are often used to express the size
limits of classes of organisms and their metabolic relationships that will be used as examples
for determination and other study procedures. Three size groups are commonly recognized
(Fenton, 1974):
1.
Microbiota
Includes soil algae (green moss type and blue green, algae), bacteria, fungi, and
protozoa. Heterotrophic microbiota are generally the principle basis of the link between plant
residues and soil animals in the food chain. Mesobiota Includes nematodes, small oligochaeta
worms (nechy traeids), small and specialized invisible insect larvae called microarthropods,
and finally earth bugs (Acarina) and springtails (Collembola) are usually most abundant in
the soil. Organisms in the soil can be extracted by means of Berlese funnel or Tulgren funnel.
The Berlese funnel is selective in that the common nematodes are filtered out but the smaller
ones escape. Baerman funnel is a Berlese funnel in which the funnel is filled with warm
water and covered with soil and wire netting or ram. Some mesobiota such as primary
bacteria, especially ticks and insects are predators. Nematodes are most abundant in mineral
soils (clay/fine type) where their biomass may be similar to that of earthworms (Overgroad-
Nielsen, 1949), but their O2 consumption is 10 times more than that of earthworms. In
agricultural soils, nematodes are a serious parasitic species on plant roots and make root
penetration into the soil difficult. Crop rotation is often the best control method.
2.
Macrobiota
Including plant roots, large insects, earthworms (Lumbicidae) and other organisms that
can be easily caught by hand, vertebrates such as rats, ground squirrels, etc. can be classified
in this group. Usually plant roots will make up the biomass component which is the largest in
the soil, but if the metabolism per gram is relatively low, it is less able to support soil
respiration for decompoiser work.
Earthworms such as nematodes make minerals in the soil abundant, especially in
calcareous clay soils reaching densities of 300/m2. All macrobiota are important in soil
mixing and maintaining the consistency of the living sponge. The height of movement of
macroscopic invertebrates living on the litter-soil interface can be sampled by placing boards
on the soil surface that animals will trap or shelter under, such as Cryptozoa (See Cole,
1946).
The mechanical breakdown of crop straw into a form that is rapidly decomposed by
microbes is one of the most important jobs performed by soil animals.
The six life forms are depicted with new shoots. The bar chart above comparing tropical
and simple forests shows the percentage of plant species.
Three methods have been used to distinguish the total metabolism (including respiration)
of soil (see Macfadyen, 1970):
1.
Difference method
The principle of this method is the subtraction of energy consumed by above-ground
herbivores from the net production of Primary production in forest communities and old
fields is rarely more than 5-10% of seasonal net primary production (see E. P. Odum, 1963;
Bray, 1964), the remaining 90% or more being metabolized or stored in the soil litter
subsystem. Conversely, different calculations indicate that only 40-60% may be reached by
heavy pasture grazing soils.
2.
Litter-fall method
In steady-state systems, the differential amount and energy value of litter input into the
soil system is a measure of decomposition. Bray and Goldan (litter fall) in the world's forests
found, as shown in Figure 11.4, that litter fall increases with decreasing elevation. Estimates
of metabolism are based on the decay of specific debris only, not including root-life
respiration and associated micro-flora.
3.
Direct Measurement
On the evolution of CO2 from intact soil in nature, the average revenue on total soil
respiration measurements includes respiration in 3 groups of biota. This method is better than
the initial one, in which the complex ground surface depiction of air gives a large and also
high estimation, since CO2 stored or trapped in the soil chamber which includes a certain
amount of respiratory output during the measurement period.
Improvements to the method include the use of either plastic boxes or cylinders that
summarize the apparent CO2 use during measurement. Table 11.2 shows a good examination
of causes with the "difference" and litter fall approaches that assume root respiration in
various forms. Field measurements on CO2 evolution make a good classification exercise
since the use of a plastic box or cylinder containing some CO2-causing KOH and a simple
titration device.
Table 11.1. CO2 evolution from forest floor measurements:
Kcal/m2
Liters
CO2/m2
GMS CO2/m2
Daily rate of musimpanas
3,0
6,0
16,0
Cold daily rate
1,2
2,4
6,4
Average rate
116
1532
4060
Since many organisms are naturally internal to the root system, some differences are not
interpreted in isolation in practice. What is more important to note is that soil respiration is
large due to the coupling between microorganisms and roots, meso-, and microfauna are very
little supported. Bunt (1954), for example, reported that nematodes accounted for only 1% of
root respiration. Englemann (1968) found that the total seasonal energy flow in Arthropoda
soil is only about 2 kkl/m2 , less than 0.1% of soil liter respiration noted in table 11.1.
This does not mean that soil animals are not important. When they are selective for toxins,
decomposition and mineral re-cycling have their measurements reduced, consequently,
insecticide toxicity to this group is about the same magnitude (See Edwards, 1969).
In the control map on the forest floor and the treatment map with naphthaline at
concentrations that killed arthropods, but had no effect on bacteria and fungi.
The use of litter bags has become a popular method to study the decomposition, mineral
cycling, and biotic coposition of the manure component of the soil subsystem. Placing
manure samples in a good nil;on mesh or glass fiber bag, the rate of decomposition can be
determined by periodic weight and the minerals released when the manure is labeled. With a
tracking Patten and Withanp (1967) reported that terrestrial laboratory mycromos are
composed of the components: manure, soil, microflora, milliapods, and leocaeta.
E.
CAVES
Large caves determine a naturally constant ambient temperature (having an average
temperature over the occupied surface area), except near the mouth (usually called the
twilight zone). Caves are inhabited by aquatic and terrestrial hetetotrophs, which depend on
organic matter washed in or brought in by bats or other animals that forage for food outside,
but use the cave as their home. Because food is so scarce, population densities are low.
Caves are natural laboratories for studying evolution because the degree of variation of
hidden and isolated relationships in a series of occasions of change in a cave is very specific.
The food chain in caves depends on the flow of forest soil or soil subsystems into 3
primary sources of food for cave animals, namely :
1.
Changes in organic particles
2.
Dissolved organic matter, absorbed by clays.
3.
Bacteria
Cave bacteria appear to be representative of non-cave species. Photosynthetic bacteria may
exist, but it is not known how they obtain useful energy from the necessary materials. Cave
animals are completely different from terrestrial animals and have specialized adaptations.
ESTUARINE ECOLOGY:
Indonesia is one of the archipelagic countries in the world that has a large coastal and
marine area. It has around 17,508 large and small islands with a sea area of about 5.8 million
km2 with a coastline length of about 81,000 km (Dahuri, 2000) and 472 large and small rivers
(Ministry of Forestry, 1999). At the mouths of rivers, estuarine ecosystems are formed, which
are a mixture of freshwater and sea water, making this region unique with the formation of
brackish water with fluctuating salinity. The difference in salinity results in freshwater tongue
and mass movement in the estuary. The continuous flow of freshwater and seawater carries
minerals, organic matter and sediments from the upstream river to the sea and vice versa from
the sea to the estuary. These nutrients affect the productivity of estuarine water areas.
Therefore, the productivity of estuaries is higher than the productivity of high seas and
freshwater ecosystems.
Estuaries are distinctive ecosystems that generally consist of mangrove forests, peat,
brackish swamps and mudflats. This ecosystem has a very important function to support a
variety of life. Estuarine areas are It is an important habitat for a large number of fish and
shrimp to spawn and raise their young. Some fish larvae spawned in the open sea also
migrate to estuarine areas in their larval phase. These areas can be considered as transitional
water areas (ecotones) between freshwater and marine habitats that are strongly influenced by
tides and are characterized by their location and morphological slope. Estuarine areas are
highly susceptible to natural or artificial damage and alteration. Waste disposal, use of waters
as a means of transportation, and changes in the watershed system are some of the causes of
degradation in the quality of estuarine ecosystems.
Estuaries are one form of wetland ecosystem, where wetlands in Indonesia cover = 38
million ha (Wibowo et al., 1996). Wetland areas, including estuaries, are experiencing
serious damage due to human population growth and development, which among other things
results in the shrinking of mangrove forests, swamp forests and peat forests and the diversity
of flora and fauna species in them, water pollution due to the use of fertilizers and pest and
disease poisons as well as various industrial and mining activities. This includes the problem
of smothering, due to agricultural activities in the upper areas that do not pay attention to soil
and water conservation techniques. Based on this, there is a need for sustainable management
of the esruaria region.
A.
DEFINITION AND TYPES ESTUARIES
Estuaries are part of the aquatic environment which is a mixing area between sea
water and fresh water coming from rivers, other freshwater sources (freshwater channels and
freshwater puddles). The estuarine environment is a transition between land and sea that is
strongly influenced by tides, but is protected from the influence of ocean waves (Kasim,
2005). According to Bengen, 2002 and Pritchard, 1976 in Tiwow (2003), estuaries are semi-
enclosed waters that are freely connected to the sea, so that sea water with high salinity can
mix with fresh water.
The mixing of seawater and freshwater has a specific mixing pattern. Based on the
mixing pattern of seawater, In general, there are 3 estuarine models that are strongly
influenced by water circulation, topography, depth and tidal patterns because the thrust and
volume of water will be very different, especially those sourced from river water (Kasim,
2005). The following is the mixing pattern of sea water and fresh water (Kasim, 2005).
1.
A salt wedge estuary is characterized by the insistence of seawater on the subsurface
layer of water at the confluence of river water and seawater. The salinity of the water
of this estuary is very different between the upper layers of water with lower salinity
compared to the higher lower layers.
2.
Pattern of even mixing between sea water and river water (well mixed estuary). This
pattern is characterized by even mixing between seawater and freshwater so that no
vertical stratification is formed, but the stratification can be horizontally whose degree
of salinity will increase in the area near the sea.
3.
Seawater dominated pattern and evenly mixed or unevenly mixed pattern (Partially
mixed estuary). This pattern will be very unstable or very dependent on the insistence
of river water and sea water. In this pattern there is uneven mixing of seawater so that
almost no salinity stratification is formed either horizontally or vertically.
4.
In some estuarine areas that have unique topography, there is sometimes a more
unique pattern. This pattern tends to exist if the estuarine area has a topography of
with a prominent formation that forms a kind of indentation at the bottom of the estuary. This
protruding surface can stagnate the water layer at the bottom of the water resulting in vertical
salinity stratification. This pattern inhibits bottom turbulence so that the bottom salinity tends
to remain with higher salinity.
The mixing of seawater and freshwater makes estuaries a unique environment
compared to other environments. The uniqueness is (Tiwow, 2003):
1.
The place where water currents meet with opposing tidal currents causes a strong
influence on sedimentation, water mixing, and other physical features, and has a
great impact on its biota.
2.
The mixing of these two kinds of water results in special environmental physical
properties that are not the same as those of river water or seawater.
3.
The changes that occur due to tides require the community within to make
physiological adjustments to the surrounding environment.
4.
The level of salinity in estuarine areas depends on the tides, the amount of
freshwater flow and currents, and the topography of the estuarine area.
Based on estuarine geomorphology, regional geological history, and different climatic
conditions, there are several types of estuaries. These estuarine types are (Nybakken, 1988):
1.
Coastal plain estuary. They are formed by rising sea levels that inundate rivers on the
sloping coast (Tiwow, 2003). Examples of coastal plain estuaries include Chesapeake
Bay, Maryland and Charleston, South Carolina (ONR, no year).
2.
Tectonic estuaries. Formed as a result of tectonic activity (earthquakes or volcanic
eruptions) resulting in subsidence of the land surface which is then inundated by
seawater at high tide (Tiwow, 2003). An example is San Francisco Bay in California
(ONR, no year).
3.
Gobah or semi-enclosed bay. Formed by sandbars that lie parallel to the shoreline,
preventing direct and open interaction with ocean waters (Tiwow, 2003). Examples are
along the Texas coast and the Florida Gulf coast.
4.
Fjord is a narrow bay (inlet) between cliffs or steep land. Commonly found in Norway,
Alaska, New Zealand, etc. Previously, fjords were glacier rivers that formed in
mountainous areas on the coast. As temperatures warmed, these glacier rivers melted,
causing sea levels to rise and flood the valleys between the mountains.
According to Nybakken (1988), estuaries can also be grouped based on their salinity
conditions, namely positive estuaries and negative estuaries. Positive estuaries or salt wedge
estuaries form a continuum ranging from estuaries with little mixing and very prominent salt
wedges, inconspicuous or prominent, to homogeneous or perfect because they produce the
same salinity vertically from the surface to the bottom at each point. Negative estuaries are
formed from seawater that comes in, enters the surface, and is slightly diluted due to mixing
with small amounts of freshwater. Evaporation rates in these estuaries are high so that the
surface water becomes hypersaline.
B.
PHYSICAL CHARACTER OF ESTUARIES
The combination of several physical properties of the estuary has an important role in
the life of estuarine biota. Some important physical properties are as follows:
1)
Salinity
Salinity in estuaries is influenced by season, estuarine topography, tides and the amount
of freshwater. During high tides, seawater moves away from the estuarine headwaters and
shifts the isohaline upstream. During low tides, the isohaline shifts downstream. These
conditions cause areas where salinity changes with the tide and have maximum salinity
fluctuations (Nybakken, 1988).
Earth's rotation also affects the salinity of estuaries, which is called the Coriolis force.
In the northern hemisphere, the coriolis force deflects freshwater flowing outward to the right
when looking at the estuary towards the sea and saltwater flowing into the estuary is shifted
to the right when looking at the estuary from the sea. The deflection of water flow in the
southern hemisphere is the opposite of the northern hemisphere (Nybakken, 1988).
Salinity is also affected by seasonal changes in evaporation. In areas where freshwater
discharge is low for half of the year, salinity is high upstream. If the freshwater flow
increases, the salinity gradient is shifted downstream towards the mouth of the estuary
(Nybakken, 1988). In estuaries, interstitial water is known to originate from the water above
the estuarine substrate. Interstitial water, mud and sand are buffered against the water above
them. The upper intertidal area (upstream) has a higher salinity than the lower intertidal area
(downstream).
2)
Substrate
The predominant substart in estuaries is mud derived from sediment brought into the
estuary by seawater and freshwater. Rivers carry mud particles in suspension. Ions from
seawater cause the mud particles to agglomerate and form larger, heavier particles that settle
to form the characteristic mud bottom. Larger particles settle faster than small particles.
Strong currents keep particles in suspension longer than weak currents so that substrates
where currents are strong are coarse (sand or gravel) and where currents are weak have
substrates with small particles of fine mud. Particles deposited in estuaries are organic so that
the substrate becomes rich in organic matter (Nybakken, 1988).
3)
Temperature
Water temperature in estuaries varies more than the surrounding water temperature
because the estuarine water volume is smaller than the larger surface area. This causes
estuarine water to heat up faster and cool down faster. Freshwater temperatures influenced by
seasonal temperature changes also cause estuarine water temperatures to vary more. Estuarine
temperatures are lower in winter and higher in summer than the surrounding waters.
Estuarine water temperature also varies vertically. Positive estuaries show that surface waters
are dominated by freshwater, while deep waters are dominated by seawater (Nybakken,
1988).
4)
Wave and current action
The shallow waters of estuaries mean that large waves do not form. Currents in
estuaries are caused by tides and river flow. Currents are usually found in canals. If the
current changes position, new channels are quickly formed and old channels become closed
(Nybakken, 1988).
5)
Turbidity
The large amount of suspended particles in estuarine waters at certain times of the year
causes the water to become very turbid. Turbidity is highest during maximum river flow and
minimum turbidity near the mouth of the estuary (Nybakken, 1988).
6)
Oxygen
The solubility of oxygen in water decreases with increasing temperature and salinity, so
the amount of oxygen in water will vary. Oxygen is greatly reduced in the substrate. The fine
particle size of the sediment limits the exchange between the interstitial water and the
overlying water column, so oxygen is depleted very quickly (Nybakken, 1988).
C.
BIOLOGICAL ASPECTS OF BIOTA COMPOSITION AND BIOLOGICAL
PRODUCTIVITY
In estuaries there are three faunal components, namely marine, freshwater and brackish
fauna. The largest fauna component is dominated by marine fauna, namely stenoalin animals
that are limited in their ability to tolerate changes in salinity (generally > 30o /oo) and
eurihalin animals that have the ability to tolerate various decreases in salinity below 30o /oo.
The brackish water component consists of species of organisms that live in mid estuarine
areas at salinities between 5 - 30o /oo . These species are not found living in both marine and
freshwater. The freshwater component usually consists of animals that are unable to tolerate
salinities above 5o /oo and is restricted to the upper reaches of estuaries.
The number of organisms that inhabit estuaries is much smaller when compared to
organisms that live in fresh and marine waters. The small number of species is mainly due to
fluctuations in environmental conditions, so that only species that have physiological
specificities are able to survive in estuaries. Besides being poor in fauna species, estuaries are
also poor in flora. The turbidity of estuarine waters means that only sticky plants can grow to
dominate.
Physically and biologically, estuaries are productive ecosystems on par with tropical
rainforests and coral reefs, because :
1.
Estuaries act as nutrient traps that are quickly recycled.
These traps are both physical and biological. Estuarine ecosystems are self-
fertilizing through :
- Retention and rapid recycling of nutrients by bottom-dwelling animals such as various
shellfish and worms.
-
Production of detritus, which are particles of leaf litter from aquatic macrophytes such as
seagrasses that are then eaten by various detritus-eating fish and shrimp.
-
Utilization of nutrients buried deep in the bottom through microbial activity (microbial
organisms such as bacteria), through plant roots that go deep into the bottom of the
estuary, or through the activities of burrowing animals on the estuarine floor such as various
worms.
2.
The diverse composition of plants in estuaries both macro plants (macrophytes) and
micro plants (microphytes), so that the photosynthesis process can take place throughout
the year.
3.
Fluctuations in water levels, especially due to tidal action, allow for the transportation of
food and nutrients needed by various estuarine organisms.
D.
ESTUARINE HABITAT
The water column in estuaries is a habitat for plankton (phytoplankton and
zooplankton), neuston (plankton-level organisms that live in the surface layer of water) and
nekton (macro organisms capable of active movement). At the bottom of the estuary live
various types of organisms both micro and macro called benthos. Each group of organisms in
their habitats carries out their respective biological functions, for example phytoplankton as
producers carry out production activities through the photosynthesis process, bacteria break
down organic matter (dead organisms) into nutrients that can be utilized by producers in the
photosynthesis process. Within one group of organisms (e.g. plankton or benthos) or between
groups of organisms (e.g. between plankton and benthos there is a tropic relationship (eating-
eating) with each other, thus forming a food web relationship.
E.
ESTUARINE FOOD WEB
The basis of the estuarine food web is the conversion of solar energy into energy in
the form of food by marsh plants. When plants die, protozoa and other microorganisms
consume the dead plant material. Small invertebrates are food for detritus. Detritus is then
eaten by fish, birds, and other predators (Hinterland Who's Who, 1993).
The abundance of food sources in estuaries and the lack of predators make estuaries a
place for the young of various animals whose adult phase does not reside in estuaries.
Estuaries are also feeding grounds for adult animals such as fish and migratory birds
(Nybakken, 1988).
In estuarine ecosystems, there are 3 (three) types of food chains that are defined based
on the form of food or how the food is consumed: grazing, detritus and osmotic. Estuarine
fauna, such as shrimp, crabs, clams, fish, and various types of worms produce and interrelate
through a complex chain and food web.
Based on its adaptation organisms in the estuarine environment have 3 (three) types of
adaptation (Kennish, 1990). namely:
1.
Morphological adaptation: organisms living in mud have fine hairs (setae) to inhibit
blockage of the respiratory surface by mud particles.
2.
Physiological adaptation: concerned with maintaining body fluid ion balance in the face
of external salinity fluctuations.
3.
Behavioral adaptation: burrowing into mud by organisms, especially invertebrates.
F.
ECOLOGICAL ROLE OF ESTUARIES
In brief, the important ecological role of estuaries is :
-
It is a source of nutrients and organic matter for parts of the estuary far from the
shoreline and adjacent to it, through tidal circulation.
-
Provides habitat for a number of economically important fish species as refuge and
feeding ground.
-
Meet the needs of various species of fish and shrimp that live offshore, but migrate to
shallow waters and shelter to produce and/or as nursery grounds for their young.
-
As potential seafood production in estuaries that are more or less left in a natural state.
Commercially valuable mollusks (Rangia euneata) produce 2900 kg of meat per ha and
13,900 kg of shell per ha in certain waters in Texas. At 2 kcal per gram wet weight, this
yield translates to about 580 kcal per m, or comparable to fish yields from the most
intensively managed and fertilized artificial ponds, bearing in mind, of course, that
mussel rearing sites require energy inputs from adjacent waters.
-
Oyster farming with rafts, as practiced in Japan, can increase five to ten times the yield
obtained by wild populations. It can thus produce as much as 2,000 kcal of protein food
per m annually (Burukawa, 1968).
In general, estuaries are utilized by humans as follows;
1)
As a place of settlement
2)
As a place to catch and cultivate fish resources
3)
As a transportation route
4)
As a port and industrial area
5)
As a forest area
6)
As a tourism spot
7)
As a plantation place
SEA ECOLOGY:
A.
MARINE ENVIRONMENT
Marine ecology is an integral collection of various abiotic (physical - chemical) and
biotic components (living organisms) that are related to each other, and interact with each
other to form a functional unit. The components are functionally separated from each other in
marine ecology, which is divided into five ecosystems. If there is a change in one ecosystem
in marine ecology, it will cause changes in other ecosystems.
Sea water has salt content because the earth is filled with mineral salts found in rocks
and soil. Examples include sodium, potassium, calcium, etc. When river water flows into the
ocean, it carries salt. The ocean waves that hit the shore can also produce salt found in rocks.
Over time, sea water becomes salty because it contains a lot of salt.
In marine ecology there are five ecosystems that have their own characteristics, both
according to morphology and physiology. As a result of human actions, marine ecology has
been damaged, this needs to be considered for a living environment that is very beneficial for
all. At present, Indonesia's seas are in a dangerous phase. High waves and strong winds have
disrupted shipping and seaside life, especially for fishermen who depend on marine products
for their livelihood.
Marine ecology is the study of marine ecosystems. Marine ecosystems are divided into
oceans, beaches, estuaries, and coral reefs, and seagrass beds. Here is an explanation of
marine ecology. The ocean was historically formed 4.4 billion years ago, when it was highly
acidic with boiling water (around 100°C) due to the heat of the Earth at the time. The acidity
of the seawater occurred because the Earth's atmosphere was filled with carbon dioxide. The
acidity of the water is what caused the high rate of weathering that took place, which
produced salts that caused the seawater to become as salty as it is today. At that time, tsunami
waves were common due to frequent asteroids hitting the Earth. The ocean tides that occurred
at that time were also of the mammoth type because the Moon was so close to the Earth. In
the sea, there are several animal and plant ecosystems. Marine ecosystems can be divided into
ocean, beach, estuary, coral reef and seagrass ecosystems. Here is an explanation of marine
ecology.
B.
ECOSYSTEM OCEAN
Seawater (oceanic) habitats are characterized by high salinity with Cl ions- reaching
55% especially in tropical ocean areas, due to high temperatures and large evaporation. In the
tropics, the sea temperature is about 25°C. The temperature difference between the upper and
lower parts is high. The boundary between the hot water layer at the top and the cold water at
the bottom is called the thermocline.
In cold regions, the temperature of the sea water is evenly distributed so that the water
can mix, so the sea surface area remains fertile and there are many plankton and fish. The
movement of water from the coast to the center causes the upper water to drop to the bottom
and vice versa, allowing the formation of a food chain that takes place balk. Marine habitats
can be distinguished based on their depth and horizontal surface area. The characteristics of
the marine habitat, namely:
•
Temperature variation or temperature variation;
•
High salt content or salinity or saltiness;
•
Sunlight penetration is high;
•
Ecosystems are not affected by the surrounding natural climate and weather;
•
The flow or wear of the sea is constantly moving due to differences in climate,
temperature and the rotation of the earth;
•
Habitats in the ocean are interconnected or related to each other; and
•
The saltwater community consists of producers, consumers, zooplankton and
decomposers.
a.
According to depth, marine ecosystems are divided as follows.
•
The littoral is the area bordering the land.
•
Neretic is an area that can still be penetrated by sunlight until the bottom is ± 300
meters deep.
•
Batial is an area that ranges in depth from 200 to 2500 m.
•
Abyssal is an area farther and deeper than the coast (1,500-10,000 m).
b.
According to its surface area horizontally, successively from the edge of the sea to the center,
the sea can be divided as follows:
•
Epipelagic is the area between the surface and the water depth of about 200 m.
•
Mesopelagic is the area below the epipelagic with a depth of 200 to 1000m. Animals
such as sharks.
•
Batiopelagic is a continental slope area with a depth of 200-2,500m. Animals that live
in this area include octopuses.
•
Abyssalpelagic is an area up to 4,000m deep; there are no plants but animals still exist.
Sunlight is unable to penetrate this area.
•
The mid-pelagic is the deepest part of the ocean (the bottom).
Depth more than 6,000 m. In this section there are usually sea catfish and Taut fish that can
emit light. The producers here are bacteria that are symbiotic with certain corals.
In the sea, low-level animals and plants have a cell osmosis pressure that is almost the
same as the osmosis pressure of seawater. Higher animals adapt by drinking a lot of water,
excreting little urine, and expelling water by osmosis through the gills. Excess salt is actively
excreted through the gills. Plants that live in the sea, for example: Seagrass plants. While the
organisms that live in the sea, among others regional division with other regions is different.
Here's an overview:
•
Organisms found in the Pelagic zone of the sea: Chaetoceros; Biddulphia; Nitzchia;
Gymnodinium; Tallassiosira; ceratium; Coccolithophoorids; Favella; Globigerina;
Protocystis; Clione; Calanus; Pelagia; Tomopteris; Saggita; Euphausia; Balaenoptera;
Physeter; Apherusa; Cylocsalpa.
•
Fishes found in the deep sea: Argyropelecus; Bthypterois; Linophryne; (Lasiognatus;
Malacostus; Edriolynchus; Gigantactis; Macropharynx
•
Benthic animals found in the deep sea : Eremicaster; Ophiura; Odostomia; Diastylis;
Ischnomesus; Storthyngura; Neotanais.
•
Organisms found in the marine neritic zone. Ulva; Ectocarpus; Alaria; Sargassum
brown algae; Rhodimenia; Polyshiphonia; Podon; Phtisicia; Thia larva; Branacle
nauplius; Acartia; Phyllosoma larva of lobster; Plathynereis; Ostrea; Snail larva;
Brittle star larva; Gadus; Solea.
1.
Coastal Ecosystems
Coastal ecosystems are located adjacent to terrestrial, marine and tidal ecosystems.
Coastal ecosystems are influenced by the daily cycle of ocean tides. Organisms that live on
the beach have structural adaptations so that they can adhere tightly to the hard substrate. As
a border area between marine ecosystems and terrestrial ecosystems, waves and winds blow
the sand from the beach to form a dune towards land. After the sand dune, there is usually a
forest called a coastal forest.
Changes in shape or better known as beach morphology are
the result of a series of coastal processes. The most dominant coastal processes occur at
Indonesia is coastal erosion. Coastal processes include circulation currents and wave
dynamics and their interaction with sediments.
Currents that occur on the coast come from global ocean currents, wind currents, tidal
currents, or wave currents. Global currents, wind currents and tidal currents are called shelf
current or coastal current. Meanwhile, wave-induced currents can be divided into littoral
current and orbital current. Littoral currents occur when the direction of the waves forms an
angle with the coastline.
Wave orbital currents are currents caused by particle velocities that move back and
forth in the direction of the wave. The amount of orbital current depends on the height and
period of the wave. The length of the influence area of this orbital current is proportional to
the wavelength. Wave currents usually occur in the area between the breaking wave and the
shoreline (surf-zone). These two currents play a dominant role in the process of coastal
erosion.
The wave mechanism in the surf zone starts with a breaking wave at a depth of
approximately 1.25 times the wave height. This breaking wave forms a bore that creeps onto
the beach and rises to the swash zone, then returns to the sea. The swash zone is only
occasionally submerged by water, and on its way back to the sea, the current will carry
sediment material. This external energy acts continuously along the coast. In parts that are
relatively less resilient, they erode faster and sediment will be transported with the backwash.
There is a new balance that will affect the shape of the coastline.
The plants in the coastal forest are quite diverse. The plants are clustered to form
certain units according to their habitat. A unit of vegetation formed because of its habitat is
called a formation. Each formation is named after the most dominant plant species. In tidal
areas alone, forests can be found, namely mangrove forests. Mangrove forests are usually
very difficult for humans to reach because there are many roots and the bottom consists of
mud.
The uppermost areas of the beach are only submerged during high tides. This area is
inhabited by several species of algae, mollusks, and mussels that feed on crabs and
shorebirds. The middle area of the beach is submerged during high and low tides. This area is
inhabited by algae, porifera, sea anemones, mussels and clams, herbivorous and carnivorous
snails, crabs, sea urchins, starfish and small fish.
The deepest areas of the coast are submerged at high and low tide. This area is
inhabited by a variety of invertebrates and fish and seaweed. Based on its vegetation
composition, the coastal forest ecosystem can be divided into two, namely the Pres-Caprae
formation and the Baringtonia formation.
a.
Pres-Caprae Formation
It is so named because the most common plant growing on sandbanks is Ipomoea pes
caprae, which is resistant to waves and wind; it is creeping and thick-leaved. Other plants
include Spinifex littorius (wind grass), Vigna, Euphorbia atoto and Canaualia martina.
Further inland are Crinum asiaticum (daffodils), Pandanus tectorius (pandanus), and
Scaeuola Fruescens (babakoan).
b.
Baringtonia Formation
This area is dominated by baringtonia plants, including
Wedelia, Thespesia, Terminalia, Guettarda, and Erythrina.
If the soil in the tidal area is muddy, then this area is a mangrove forest that has a breath
root. Breath roots are an adaptation of plants in muddy areas that lack oxygen. In addition to
functioning to take in oxygen, these roots can also be used as a barrier from tidal waves.
Plants in mangrove forests include Nypa, Acathus, Rhizophora, and Cerbera.
If the tidal soil is not too wet, trees that often grow are: Heriticra, Lumnitzera,
Acgicras, and Cylocarpus.
For life, especially in the tropics, beaches can be utilized as :
1.
Salt pond area
2.
Tidal farming area
3.
Coconut and banana plantation areas
4.
Tourism object
5.
Development areas for folk craft industries characterized by coastal areas, etc.
2.
Coral Reef Ecosystem
The term coral reef is composed of two words, reef and coral, which when standing
alone will have a much different meaning when the two words are combined. The term coral
reef itself is very different from reef coral, because one indicates an ecosystem and the other
word refers to a benthic community or one that lives at the bottom of the substrate. The
following is a brief definition of reef, coral, reef coral, and coral reef.
Reef
Massive deposits of limestone, mainly calcium carbonate (CaCO3), produced mainly
by reef animals and other lime-secreting biota, such as calcareous algae and molluscs.
Biogenic limestone construction is the basic structure of a coastal ecosystem. In the world of
marine navigation, a reef is a sea ridge formed by coral or sand near the surface of the water.
Coral Coral, also called stony coral, is an animal of the order Scleractinia, which is capable of
secreting CaCO3. Single coral animals are generally called polyps.
a.
Coral reef.
The main builder of reef structure, usually referred to as hermatypic coral. Unlike rock,
which is an inanimate object.
Tropical seafloor ecosystems are built primarily by lime (CaCO3)-producing marine
biota, especially rock corals and calcareous algae, together with other bottom-dwelling biota
such as mollusks, crustaceans, echinoderms, polychaetes, porifera, and tunicates as well as
other biota that live freely in the surrounding waters, including plankton and nekton species.
b.
Types of coral reefs
Based on the shape and relationship of coral reef growth boundaries with land masses,
there are three classifications of coral reef types that are still widely used. The three types are:
- Fringing reefs
Fringing or successional reefs develop on the majority of the coastline of large islands.
Development can reach depths of up to 40 meters with growth upward and outward toward
the open sea. In the process of development, these reefs are circular in shape characterized by
the formation of tires or sections of dead coral deposits surrounding the island. On steep
shores, reef growth is clearly vertical. Examples: Bunaken (Sulawesi), P. Panaitan (Banten),
Nusa Dua (Bali).
-
Barrier reefs
These reefs are located at a relatively long distance from the island, about 0.52 km out to
sea, bordered by waters up to 75 meters deep. Sometimes they form lagoons (water columns)
or water gaps that are tens of kilometers wide. Generally, barrier reefs grow around very
large islands or continents and form discontinuous coral island clusters. Examples: Great
Barrier Reef (Australia), Spermonde (South Sulawesi), Banggai Islands (Central Sulawesi).
-
Ring reefs (atolls)
Ring reefs surround the boundaries of submerged volcanic islands so that there is no land
boundary. According to Darwin, ring reefs are an advanced process of barrier reefs, with an
average depth of 45 meters. Examples: Taka Bone Rate (Sulawesi), Maratua (South
Kalimantan), Dana Island (NTT), Mapia (Papua).
However, not all coral reefs in Indonesia can be classified into one of the three types
above. Thus, there is one more type of coral reef, namely:
- Flat reefs / patch reefs
Patch reefs, sometimes referred to as flat islands. These reefs grow from the bottom up
to the surface and, over geologic time, assist in the formation of flat islands. Generally, these
islands will develop horizontally or vertically at relatively shallow depths.
3.
Estuarine ecosystem
Estuaries are where rivers meet the sea. Estuaries are often lined by extensive intertidal
mudflats or salt marshes. The salinity of the water changes gradually from freshwater to
marine areas. It is also affected by the daily cycle of the tides. Nutrients from rivers enrich
the estuary.
The plant communities that live in estuaries include salt marsh grasses, algae and
phytoplankton. The animal community includes a variety of worms, clams, crabs and fish.
There are even some marine invertebrates and marine fish that use estuaries as mating
grounds or migrate to freshwater habitats. Estuaries are also feeding grounds for semi-aquatic
vertebrates, namely waterfowl. Estuarine is a semi-enclosed body of water located
downstream of a river and still in contact with the sea, allowing the mixing of sea water and
fresh water from rivers or drainage from river mouths, bays, tidal marshes. The shape of
estuaries varies and depends largely on the size of the river, the tidal range and the shape of
the shoreline. Most estuaries are dominated by muddy substrate derived from sediment
carried by both freshwater and seawater. Since the deposited particles are mostly organic, the
estuarine bottom substrate is usually rich in organic matter. This organic material is the main
food supply for estuarine organisms.
1.
Animals
-
Endemic species (living their entire lives in estuaries) such as a wide variety of
shellfish and crabs and a wide variety of fish.
-
Species that live in estuaries temporarily include larvae, some shrimp and fish species
that immigrate to the ocean as adults.
-
Fish species that use estuaries as immigration routes from sea to river and vice versa
such as eels and salmon.
2.
Plants
-
Seagrass Plants (sea grass)
-
Macro algae (sea weeds) that grow on the bottom of the water.
-
Micro algae that live as vegetable plankton or live attached to seagrass leaves.
In brief, the important ecological role of estuaries is :
•
Is a source of nutrients and organic matter for parts of the estuary far from the shoreline
as well as adjacent ones
By doing so, through tidal circulation.
•
Provides habitat for a number of economically important fish species as refuge and
feeding ground.
•
Meet the needs of various species of fish and shrimp that live offshore, but migrate to
shallow waters and shelter to produce and/or as nursery grounds for their young.
•
As a potential seafood production in estuaries that are more or less left in a natural
state. Commercially valuable mollusks (Rangia euneata) produce 2900 kg of meat per
ha and 13,900 kg of shell per ha in certain waters in Texas.
•
Oyster farming with rafts, as practiced in Japan, can increase five to ten times the
harvest obtained by wild populations. It can thus produce as much as 2,000 kcal of
protein food per m every year.
Based on circulation patterns and water stratification estuaries are divided into three
types:
•
Fully stratified estuaries or salt wedge estuaries. Defined by a clear boundary
between freshwater and saltwater. Estuaries of this type are found in areas where
freshwater inflow from large rivers is more dominant than saltwater intrusion from the
tide-influenced sea.
•
Partially stratified estuaries are the most common type. In these estuaries, freshwater
flow from rivers is balanced by seawater entering through tidal currents, mixing of
water can occur due to turbulence that occurs periodically by tidal action.
•
Perfectly mixed estuaries or vertically homogeneous estuaries. This type of estuary
is found in locations where tidal currents are dominant and strong, so the estuarine
water is perfectly mixed and there is no stratification.
In estuarine ecosystems, there are 3 (three) types of food chains that are defined based
on the form of food or how the food is consumed: grazing, detritus and osmotic. Estuarine
fauna, such as shrimp, crabs, clams, fish, and various types of worms produce and interrelate
through a complex chain and food web.
Utilization in the estuarine area includes fisheries, forestry, industry, transportation,
tourism, agriculture, gardening and settlements, is the third determining factor that needs to
be studied to make changes towards improving management for the realization of natural
resource conservation and development in the Estuarine area.
Planning and management of estuarine areas is approached by using biophysical and
socio-economic potential and spatial planning of the area, analyzing the three determining
components which include supply potential, demand potential and utilization to determine the
condition of natural resources and human needs in the context of sustainable development.
Framework approach
4.
Seagrass Plant Ecosystem
Seagrass beds spread almost all over the coastal waters. You will easily recognize this
plant. Seagrass beds are usually very similar and even resemble grasslands on land and live at
relatively shallow depths (1-10 meters) except for some species such as Halodule sp.,
Syringodium sp. and Thalassodendrum sp., which are also found at depths of up to 20 meters
with relatively low light penetration. In fact, Halophila species have been reported at a depth
of 90 meters by Taylor (1928) as written in Den Hartog (1970). However Generally, most
seagrass beds are spread at a depth of 1 - 10 meters. In some shallow waters, we can see
seagrass beds with a fairly high density that gives the impression of green on the bottom of
the water.
Seagrass plants are the only flowering and vascular plants that have fully adapted to
living immersed in seawater. Seagrass plants clearly have roots, stems, leaves, fruits and
seeds. Seagrasses belong to the class monocotyledoneae, subclass Alismatidae tribe
Hydroecharitaceae with examples of Syrinsodium isoetifolium this plant has several
properties that allow it to live in the marine environment, namely:
