237
12.2.5 Aggregation of Microplastics with Marine
Biogenic Particles
Angela Stippkugel
1*
, Jan Michels
1,2
1
GEOMAR Helmholtz Centre for Ocean Research Kiel,
Düsternbrooker Weg 20, 24105 Kiel, Germany
2
present Address: Department of Functional Morphology
and Biomechanics, Institute of Zoology, Christian-AlbrechtsUniversität zu Kiel, Am Botanischen Garten 1–9, D-24118
Kiel, Germany
*corresponding author: astippkugel@geomar.de
Keywords: Coagulation, Marine plastic pollution, Marine
biogenic particles, Microplastics
Although plastic pollution of the oceans has resulted in a
dramatic accumulation of microplastics (i.e., plastic particles
smaller than five millimeters) in the marine environment,
knowledge of the impact of microplastics on biological processes in marine ecosystems is still very scarce. Today,
microplastics are present everywhere in the oceans, including even very remote habitats such as deep-sea sediments
and sea ice. However, the concentration of microplastics in
the surface ocean is considerably lower than expected given
the ongoing replenishment of microplastics and the tendency
of many plastic types to float. It has been hypothesized that
microplastics leave the upper ocean by aggregation and subsequent sedimentation. In the present study, we tested this
hypothesis by investigating the interactions of microplastics
with marine biogenic particles collected in the Bay of Kiel.
Our laboratory experiments performed with roller tanks
revealed a large potential of microplastics to rapidly coagulate with biogenic particles. In control experiments with
microplastics and either filtered seawater or artificial seawater, only single microplastics spontaneously attached to each
other. Together with the biogenic particles, the microplastics
formed relatively large aggregates within a few days. In the
presence of microplastics, the particle aggregation was faster
and more pronounced compared with that observed between
biogenic particles only. The results of our study suggest that
microplastics become involved in the natural particle aggregation processes taking place in the marine water column.
We assume that the aggregation of microplastics with marine
biogenic particles facilitates the export of microplastics from
the surface ocean and plays a significant role in the redistribution of microplastics in the oceans.
12.2.6 Quantitative Investigation of Microplastic
Interaction with Blue Mussel Adults and Larvae
Sinja Rist
1*
, Ida Mathilde Steensgaard
1
, Olgac Guven
2
, Lene
Friis Møller
2
, Torkel Gissel Nielsen
2
, Lene Hartmann
Jensen
2
, Anders Baun
1
, Nanna B. Hartmann
1
1
Department of Environmental Engineering, Technical
University of Denmark, Bygningstorvet, Building 115, Kgs.
Lyngby, Denmark
2
National Institute for Aquatic Resources, Technical
University of Denmark, Kemitorvet, Building 202, Kgs.
Lyngby, Denmark
*corresponding author: siri@env.dtu.dk
Keywords: Microplastics, Mytilus edulis, Uptake,
Quantification
An increasing number of studies are showing that marine
invertebrates ingest microplastics (< 5 mm). One of the species studied in this context is the blue mussel (Mytilus edulis). As a filter feeder it is considered especially susceptible
to microplastics uptake and it is a key species of benthic ecosystems. Although it is known that blue mussels ingest
microplastics in a wide range of sizes, and the particles have
been found to impair their physiology, the dynamics of
ingestion and egestion of microplastics are only poorly
understood and rarely quantified. Furthermore, all studies
have so far been carried out with adult mussels and it is
unclear how blue mussel larvae are affected. The aim of this
research was therefore to investigate the fate of microplastics
during an exposure of blue mussels and to quantify particle
ingestion and egestion in adult mussels as well as mussel
larvae. In the first stage methodologies for particle quantification in the whole animals were developed. These included
enzymatic digestion protocols and fluorescence measurements. Subsequently, mussels were exposed to different
exposure scenarios (varying microplastic sizes, concentrations, food availability and exposure time) and the fate of the
particles was examined in the animals, in their feces and in
the water. The extent to which the animals egest the taken up
particles was examined by transferring them to clean water
after exposure. This study found that not only adult blue
mussels but also the larvae ingest a wide range of particle
sizes. Furthermore, we investigated a wide range of particle
sizes and how the ingested quantities relate to particle size,
concentration, time and food availability. This work contributes to enhancing our knowledge on the mechanisms of
microplastics – blue mussel interaction, which is decisive for
understanding and evaluating the potential hazard of microplastics to this species.
12.2.7 Does Heat Stress Amplify the Negative
Effects of Microplastics on Two Bivalve Species?
Vanessa Herhoffer
1*
, Mone Ota
2
, Masahiro Nakoka
2
, Mark
Lenz
3
1
Department of Economics, Faculty of Business,
Economics and Social Sciences, Kiel University, Wilhelm–
Seelig-Platz 1, 24118 Kiel, Germany
2
Akkeshi Marine Station, Hokkaido University, Aikappu
1, Akkeshi, Hokkaido 088-1113, Japan
3
GEOMAR Helmholtz Centre for Ocean Research Kiel,
Düsternbrooker Weg 20, 24105 Kiel, Germany
*corresponding author: vanessa.herhoffer@web.de
Appendices
12.2.5 Aggregation of Microplastics with Marine
Biogenic Particles
Angela Stippkugel
1*
, Jan Michels
1,2
1
GEOMAR Helmholtz Centre for Ocean Research Kiel,
Düsternbrooker Weg 20, 24105 Kiel, Germany
2
present Address: Department of Functional Morphology
and Biomechanics, Institute of Zoology, Christian-AlbrechtsUniversität zu Kiel, Am Botanischen Garten 1–9, D-24118
Kiel, Germany
*corresponding author: astippkugel@geomar.de
Keywords: Coagulation, Marine plastic pollution, Marine
biogenic particles, Microplastics
Although plastic pollution of the oceans has resulted in a
dramatic accumulation of microplastics (i.e., plastic particles
smaller than five millimeters) in the marine environment,
knowledge of the impact of microplastics on biological processes in marine ecosystems is still very scarce. Today,
microplastics are present everywhere in the oceans, including even very remote habitats such as deep-sea sediments
and sea ice. However, the concentration of microplastics in
the surface ocean is considerably lower than expected given
the ongoing replenishment of microplastics and the tendency
of many plastic types to float. It has been hypothesized that
microplastics leave the upper ocean by aggregation and subsequent sedimentation. In the present study, we tested this
hypothesis by investigating the interactions of microplastics
with marine biogenic particles collected in the Bay of Kiel.
Our laboratory experiments performed with roller tanks
revealed a large potential of microplastics to rapidly coagulate with biogenic particles. In control experiments with
microplastics and either filtered seawater or artificial seawater, only single microplastics spontaneously attached to each
other. Together with the biogenic particles, the microplastics
formed relatively large aggregates within a few days. In the
presence of microplastics, the particle aggregation was faster
and more pronounced compared with that observed between
biogenic particles only. The results of our study suggest that
microplastics become involved in the natural particle aggregation processes taking place in the marine water column.
We assume that the aggregation of microplastics with marine
biogenic particles facilitates the export of microplastics from
the surface ocean and plays a significant role in the redistribution of microplastics in the oceans.
12.2.6 Quantitative Investigation of Microplastic
Interaction with Blue Mussel Adults and Larvae
Sinja Rist
1*
, Ida Mathilde Steensgaard
1
, Olgac Guven
2
, Lene
Friis Møller
2
, Torkel Gissel Nielsen
2
, Lene Hartmann
Jensen
2
, Anders Baun
1
, Nanna B. Hartmann
1
1
Department of Environmental Engineering, Technical
University of Denmark, Bygningstorvet, Building 115, Kgs.
Lyngby, Denmark
2
National Institute for Aquatic Resources, Technical
University of Denmark, Kemitorvet, Building 202, Kgs.
Lyngby, Denmark
*corresponding author: siri@env.dtu.dk
Keywords: Microplastics, Mytilus edulis, Uptake,
Quantification
An increasing number of studies are showing that marine
invertebrates ingest microplastics (< 5 mm). One of the species studied in this context is the blue mussel (Mytilus edulis). As a filter feeder it is considered especially susceptible
to microplastics uptake and it is a key species of benthic ecosystems. Although it is known that blue mussels ingest
microplastics in a wide range of sizes, and the particles have
been found to impair their physiology, the dynamics of
ingestion and egestion of microplastics are only poorly
understood and rarely quantified. Furthermore, all studies
have so far been carried out with adult mussels and it is
unclear how blue mussel larvae are affected. The aim of this
research was therefore to investigate the fate of microplastics
during an exposure of blue mussels and to quantify particle
ingestion and egestion in adult mussels as well as mussel
larvae. In the first stage methodologies for particle quantification in the whole animals were developed. These included
enzymatic digestion protocols and fluorescence measurements. Subsequently, mussels were exposed to different
exposure scenarios (varying microplastic sizes, concentrations, food availability and exposure time) and the fate of the
particles was examined in the animals, in their feces and in
the water. The extent to which the animals egest the taken up
particles was examined by transferring them to clean water
after exposure. This study found that not only adult blue
mussels but also the larvae ingest a wide range of particle
sizes. Furthermore, we investigated a wide range of particle
sizes and how the ingested quantities relate to particle size,
concentration, time and food availability. This work contributes to enhancing our knowledge on the mechanisms of
microplastics – blue mussel interaction, which is decisive for
understanding and evaluating the potential hazard of microplastics to this species.
12.2.7 Does Heat Stress Amplify the Negative
Effects of Microplastics on Two Bivalve Species?
Vanessa Herhoffer
1*
, Mone Ota
2
, Masahiro Nakoka
2
, Mark
Lenz
3
1
Department of Economics, Faculty of Business,
Economics and Social Sciences, Kiel University, Wilhelm–
Seelig-Platz 1, 24118 Kiel, Germany
2
Akkeshi Marine Station, Hokkaido University, Aikappu
1, Akkeshi, Hokkaido 088-1113, Japan
3
GEOMAR Helmholtz Centre for Ocean Research Kiel,
Düsternbrooker Weg 20, 24105 Kiel, Germany
*corresponding author: vanessa.herhoffer@web.de
Appendices