238
Keywords: Microplastics, Global warming, Filter feeders,
Interactive effects, Respiration rate
Small plastics particles (< 5 mm), so called microplastics, are now ubiquitous in the marine environment and can
mistakenly be taken up by organisms like benthic filter feeders – what can affect them negatively. Furthermore, in the
past 50 years, the average surface temperature of the world’s
ocean has increased and will continue to rise in the future.
The two stressors therefore currently act in concert in many
coastal ecosystems worldwide. In an experimental approach,
we addressed the question whether elevated temperatures
can amplify the negative effects of microplastics on marine
benthic filter feeders. We investigated this in the blue mussel
Mytilus trossulus (N = 120) and in the Pacific oyster
Crassostrea gigas (N = 120) by performing a laboratory
experiment in which the test animals were subjected to four
different microplastics concentrations (0, 2, 20 and
200 mg/L) and three elevated temperature levels (17, 20 and
23 °C), simultaneously. The animals were collected near
Akkeshi in Japan, where 17 °C is the ambient summer sea
surface temperature. After 82 days of exposure, respiration
rates of both test organisms were found to decline with
increasing microplastics concentrations and increasing
water temperatures. However, elevated water temperatures
did not amplify the negative effects of microplastics on the
performance of the bivalve species we tested. We discuss
these results in the context of the increasing awareness of
microplastics as a further component of marine global
change.
12.2.8 Impact of Synthetic and Natural
Microparticles in the Shrimp Palaemon varians
Mara Weidung
1*
, Reinhard Saborowski
1
, Lars Gutow
1
1
Alfred Wegener Institute, Am Handelshafen 12, 27570
Bremerhaven, Germany
*corresponding author: mara.weidung@awi.de
Keywords: Microplastics, Titanium dioxide, Oxidative
stress
Microplastics (< 5 mm) have become ubiquitous in
waters. The smaller they are the easier they can be taken up
by aquatic organisms. Once ingested they can cause various
harmful effects. This study investigates the effects of size of
artificial and natural particles on the induction of cellular
stress in the common ditch shrimp (Palaemon varians). The
study includes feeding experiments with different sizes of
fluorescent microplastic particles, nanosized titanium dioxide particles and silica powder of diatoms as a reference for
natural particles. The uptake and distribution of particles in
the digestive organs was observed by fluorescence microscopy. As marker for oxidative stress we measured the activities of the antioxidant enzymes catalase and superoxide
dismutase in extracts of the midgut glands of animals which
were fed with particles from 2 to 48 h. The larger particles
(2 μm and 10 μm) remained in the stomach and in the lumen
of the gut. The smaller particles (0.1 μm) were translocated
into the surrounding tissues and entered the cells of the midgut gland. Crustaceans have a stomach with fine-meshed filter structures which prevent the uptake of particles > 1 μm
into the digestive gland. Superoxide dismutase (SOD) activity was rapidly induced when the animals were exposed to
0.1 μm plastic particles. The activity increased within 2 h
after microplastic ingestion and remained high after 48 h.
Slight difference appeared between natural and synthetic
particles. The diatom powder also induced SOD activity
which, however, continuously decreased with time. It can be
assumed that any particles < 1 μm enter the cells of the midgut gland and induce oxidative stress. Histological analysis
of cryosections and scanning electron microscopy will help
to clear up how far the different particles penetrate the cells
of the digestive organs.
12.2.9 Differential Effects of Microplastics
on Growth and Survival of Corals
Jessica Reichert
1*
, Angelina Arnold
1
, Patrick Schubert
1
,
Thomas Wilke
1
1
Department of Animal Ecology & Systematics, Justus
Liebig University Giessen, Heinrich-Buff-Ring 26-32 (IFZ),
D-35392 Giessen, Germany
*corresponding author: Jessica.Reichert@allzool.bio.
uni-giessen.de
Keywords: 3D scanning, Growth rates, Microplastic,
Scleractinian corals, Survival
Microplastics (i.e., plastic fragments <5 mm) gained
recent attention in public and science as they are considered to be a major threat to marine ecosystems. As these
plastic particles are mainly of terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened.
Previously it has been shown that scleractinian corals ingest
microplastic particles. However, little is known about other
responses and the subsequent effects on health and survival
of the coral holobiont under realistic long-term conditions.
Thus, the influence of low microplastic concentrations
(polyethylene, size 35–650 μm, concentration 200 particles
L
−1
) on scleractinian corals (Acropora, Pocillopora, and
Porites spp.) was examined in a 9-month fully controlled
lab experiment. In particular, we studied growth and survival rates of the corals by utilizing 3D scanning and 3D
model analyses. Our preliminary results indicate that different species responded differently to microplastic exposure. Both increases and decreases in growth and survival
rates might be associated with the exposure to microplastics. This is an important baseline study of scleractinian
corals from three genera showing the diverse impacts of
microplastic exposure, calling for further investigations of
the effects of microplastics on the integrity of the coral
holobiont.
Appendices
Keywords: Microplastics, Global warming, Filter feeders,
Interactive effects, Respiration rate
Small plastics particles (< 5 mm), so called microplastics, are now ubiquitous in the marine environment and can
mistakenly be taken up by organisms like benthic filter feeders – what can affect them negatively. Furthermore, in the
past 50 years, the average surface temperature of the world’s
ocean has increased and will continue to rise in the future.
The two stressors therefore currently act in concert in many
coastal ecosystems worldwide. In an experimental approach,
we addressed the question whether elevated temperatures
can amplify the negative effects of microplastics on marine
benthic filter feeders. We investigated this in the blue mussel
Mytilus trossulus (N = 120) and in the Pacific oyster
Crassostrea gigas (N = 120) by performing a laboratory
experiment in which the test animals were subjected to four
different microplastics concentrations (0, 2, 20 and
200 mg/L) and three elevated temperature levels (17, 20 and
23 °C), simultaneously. The animals were collected near
Akkeshi in Japan, where 17 °C is the ambient summer sea
surface temperature. After 82 days of exposure, respiration
rates of both test organisms were found to decline with
increasing microplastics concentrations and increasing
water temperatures. However, elevated water temperatures
did not amplify the negative effects of microplastics on the
performance of the bivalve species we tested. We discuss
these results in the context of the increasing awareness of
microplastics as a further component of marine global
change.
12.2.8 Impact of Synthetic and Natural
Microparticles in the Shrimp Palaemon varians
Mara Weidung
1*
, Reinhard Saborowski
1
, Lars Gutow
1
1
Alfred Wegener Institute, Am Handelshafen 12, 27570
Bremerhaven, Germany
*corresponding author: mara.weidung@awi.de
Keywords: Microplastics, Titanium dioxide, Oxidative
stress
Microplastics (< 5 mm) have become ubiquitous in
waters. The smaller they are the easier they can be taken up
by aquatic organisms. Once ingested they can cause various
harmful effects. This study investigates the effects of size of
artificial and natural particles on the induction of cellular
stress in the common ditch shrimp (Palaemon varians). The
study includes feeding experiments with different sizes of
fluorescent microplastic particles, nanosized titanium dioxide particles and silica powder of diatoms as a reference for
natural particles. The uptake and distribution of particles in
the digestive organs was observed by fluorescence microscopy. As marker for oxidative stress we measured the activities of the antioxidant enzymes catalase and superoxide
dismutase in extracts of the midgut glands of animals which
were fed with particles from 2 to 48 h. The larger particles
(2 μm and 10 μm) remained in the stomach and in the lumen
of the gut. The smaller particles (0.1 μm) were translocated
into the surrounding tissues and entered the cells of the midgut gland. Crustaceans have a stomach with fine-meshed filter structures which prevent the uptake of particles > 1 μm
into the digestive gland. Superoxide dismutase (SOD) activity was rapidly induced when the animals were exposed to
0.1 μm plastic particles. The activity increased within 2 h
after microplastic ingestion and remained high after 48 h.
Slight difference appeared between natural and synthetic
particles. The diatom powder also induced SOD activity
which, however, continuously decreased with time. It can be
assumed that any particles < 1 μm enter the cells of the midgut gland and induce oxidative stress. Histological analysis
of cryosections and scanning electron microscopy will help
to clear up how far the different particles penetrate the cells
of the digestive organs.
12.2.9 Differential Effects of Microplastics
on Growth and Survival of Corals
Jessica Reichert
1*
, Angelina Arnold
1
, Patrick Schubert
1
,
Thomas Wilke
1
1
Department of Animal Ecology & Systematics, Justus
Liebig University Giessen, Heinrich-Buff-Ring 26-32 (IFZ),
D-35392 Giessen, Germany
*corresponding author: Jessica.Reichert@allzool.bio.
uni-giessen.de
Keywords: 3D scanning, Growth rates, Microplastic,
Scleractinian corals, Survival
Microplastics (i.e., plastic fragments <5 mm) gained
recent attention in public and science as they are considered to be a major threat to marine ecosystems. As these
plastic particles are mainly of terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened.
Previously it has been shown that scleractinian corals ingest
microplastic particles. However, little is known about other
responses and the subsequent effects on health and survival
of the coral holobiont under realistic long-term conditions.
Thus, the influence of low microplastic concentrations
(polyethylene, size 35–650 μm, concentration 200 particles
L
−1
) on scleractinian corals (Acropora, Pocillopora, and
Porites spp.) was examined in a 9-month fully controlled
lab experiment. In particular, we studied growth and survival rates of the corals by utilizing 3D scanning and 3D
model analyses. Our preliminary results indicate that different species responded differently to microplastic exposure. Both increases and decreases in growth and survival
rates might be associated with the exposure to microplastics. This is an important baseline study of scleractinian
corals from three genera showing the diverse impacts of
microplastic exposure, calling for further investigations of
the effects of microplastics on the integrity of the coral
holobiont.
Appendices