This presentation provides an insight about how living organisms play an essential role in bio-geochemical cycles through coastal systems.These organisms are themselves vulnerable to rapid changes which take place in the coastal zone due to anthropogenic activities, but changes in the structure of populations of organisms will in turn affect the geochemistry of the habitat, to a point where such cycles might become dysfunctional. The consequences can be at global level leading to an unbalance influxes of energy and minerals at the interface between land and sea.

1. BISMA GULZAR
Ph.D Scholar
SKUAST-Kashmir
HUMAN IMPACTS - MODIFICATION OF COASTAL HABITATS
AND MAJOR ALTERATIONS OF BIOGEOCHEMICAL CYCLES;
CONTAMINANTS ;BENTHIC ORGANISMS AS POLLUTION
INDICATORS AND BIOMONITORS

2. INTRODUCTION
 Benthos are the organisms
that live in the benthic zone,
and are different from those
elsewhere in the water
column.
 Many organisms adapted
to deep-water pressure
cannot survive in the upper
parts of the water column.
The pressure difference can
be very significant
(approximately one
atmosphere for each 10
meters of water depth).

3. CONTD…
• The benthic zone is the
ecological region at the
lowest level of a body of
water such as an ocean or
a lake, including the
sediment surface and some
sub-surface layers.
• Organisms living in this
zone are called benthos,
e.g. the benthic
invertebrate community,
including crustaceans and
polychaetes

4. CONTD…
• As light does not penetrate very deep into ocean-
water, the energy source for the benthic ecosystem is
often organic matter from higher up in the water
column that drifts down to the depths.
• This dead and decaying matter sustains the benthic
food chain; most organisms in the benthic zone are
scavengers or detritivores. Some microorganisms use
chemosynthesis to produce biomass.

5. CLIMATE IMPACT
• Present day climate change is already impacting
deep sea environments, as evidenced by
increased deep sea temperature (Purkey and
Johnson, 2010), deoxygenation, lowered pH of
intermediate deep waters (Byrne et al., 2010),
Despite emerging evidence that climate driven
changes in deepsea environmental conditions
may perturb the functioning of oceanfloor
ecosystems (Smith et al., 2007, 2008; Dunlop et
al., 2016; Yasuhara et al., 2016).

7. CONTD…
 The increased availability of nutrients derived from
autochthonous or allochthonous sources, combined with
the high availability of light and substrates within the
littoral, results in an intense periphyton primary
production in the littoral benthic zone. Hence, periphyton
production can exceed pelagic primary production in large
oligotrophic lakes and can contribute up to 95% of whole-
lake primary production (Vadeboncoeur et al., 2001).
 Furthermore, the increased nutrient availability and higher
habitat heterogeneity lead to higher rates of secondary
production than in the pelagic or profundal zones

8. CONTD…
 The increased availability of nutrients derived from
autochthonous or allochthonous sources, combined with
the high availability of light and substrates within the
littoral, results in an intense periphyton primary
production in the littoral benthic zone. Hence, periphyton
production can exceed pelagic primary production in large
oligotrophic lakes and can contribute up to 95% of whole-
lake primary production (Vadeboncoeur et al., 2001).
 Furthermore, the increased nutrient availability and higher
habitat heterogeneity lead to higher rates of secondary
production than in the pelagic or profundal zones

12. BIOGEOCHEMICAL CYCLING
Biogeochemical cycles incorporate both the
pelagic and benthic habitats and thus
integrate processes and interactions in both
environments.

13. • There is strong cycling of nutrients and dependency
between pelagic and benthic environments
• The benthic biogeochemical processes are essentially
driven by pelagic processes, fuelled by the deposition
of pelagic material (e.g., organic matter, calcium
carbonate). In response, sediments transform the
deposited material (such as through degradation and
dissolution) back into nutrients available for uptake in
the water column.

14. IMPACTS TO BIOGEOCHEMICAL CYCLES
• Biogeochemical coupling between benthic and pelagic
habitats seems to be significantly altered with
eutrophication. After phytoplankton bloom events, a
net transport downwards of nutrients and organic
matter will occur from the pelagic zone to the benthic
zone as phytoplankton sediment out of the water
column and decompose.
• Eutrophication will favor cyanobacterial dominance in
both marine and freshwater systems (Paerl and
Huisman 2008), and many cyanobacteria transfer
sequestered P and fixed N from the sediments to the
water column (Barbiero and Welch 1992; Istvánovics
et al. 1993, 2002; Carey et al. 2008),

15. • Invasive species can impact biogeochemical
cycles in addition to altering trophic
interactions and/or organism movement.
• For example, through their foraging
behaviors, common carp release nutrients
from sediments, increasing nutrients available
for phytoplankton growth (Matsuzaki et al.
2007)

16. BENTHOS AS BIOINDICATORS
• Bioindicators are living organisms such as
plants, planktons, animals, and microbes,
which are utilized to screen the health of the
natural ecosystem in the environment. They
are used for assessing environmental health
and biogeographic changes taking place in
the environment.

17. CONTD…
Benthic invertebrate
communities are often
used as indicators of
aquatic ecosystem health
because many species are
sensitive to pollution and
sudden changes in their
environment.
The orders Ephemoptera
(mayflies), Plectoptera
(stoneflies), and
Trichoptera (caddisflies)
are pollution sensitive
taxa.

18. Are useful indicators of the health or condition of wetlands and other
water bodies.
Respond to many kinds of pollution, including chemical pollution and
physical disturbance to the landscape around the site, wetland
structure, and hydrology.
Great candidates for biological monitoring…
BIOMONITORS
Heptageniidae sp.
(Mayfly larva)
Hydropsyche sp.
(Caddisfly larva)
Perlodidae sp.
(Stonefly larva)
(bottom-dwelling) (animals w/o backbones visible to naked eye)

20. Aquatic macroinvertebrates live in water for at
least part of their life cycle.

21. THANK YOU ALL