“The Sound of the Seafloor” was shown at the “Beneath the Waves Film Festival” in Portland, Maine, at the 2016 Benthic Ecology Meeting.

 

Sediment reworking by the lugworm Arenicola marina. The lugworm was placed in a thin aquarium (dimensions 40×30×1.2cm) equipped with an oxygen-sensitive planar optode (pink foil on the backside of the aquarium) and a porewater pressure sensor deployed
through the front plate. The surface sediment on the left is being subducted due to ingestion by the lugworm at depth and defecation on the sediment surface on the right side. Video is shown at 10.000-fold speed (66 hours in 24 seconds).

 

Sediment reworking by the thalassinid crustacean Neotrypaea californiensis. The thalassinid was placed in a thin aquarium with dimensions 50×57×5 cm. As burrow establishment progresses, the thalassinid creates new openings at the sediment surface. Note the color change of the sediment surrounding the burrow due to the oxidation of iron mono-sulfides (black) and di-sulfides (pyrite, gray) with oxygen delivered to the burrow and the surrounding sediment by the hydraulic activities of the thalassinid. Video is shown at 10.000-fold speed (91 hours in 33 seconds).

 

Sediment reworking by the tellinid bivalve Macoma nasuta. Shown is a top-down view of an aquarium with dimensions 10×10×20 cm. The inhalant siphon protrudes the sediment surface to ingest oxygenated water and food particles. The exhalant siphon is
subsurface and its approximate location is several cm below the area of conspicuous particle movement on the left side. Brownish color of the sediment surface relates to high abundance of microphytobenthos. Video is shown at 10.000-fold speed (86 hours in 31 seconds).

 

Peristalsis by juvenile lugworms. The lugworms were placed outside the sediment. When within the sediment, each peristaltic wave transports water between the burrow wall and the lugworm body in the tail-to-head direction. Adult lugworms perform 6-10 peristaltic
waves per minute, each transporting approximately 0.2 mL of water. Video is shown in real-time and at 10-fold speed.

 

Burrow ventilation by the burrowing thalassinid crustacean Neotrypaea californiensis. Burrow ventilation is achieved by pleopod beating with the abdomen located in the narrow part of the burrow. Typical adult individuals perform 15-30 beats per minute, each transporting about 0.3 mL of water. Video is shown in real time and at 10-fold speed.

 

Irrigation by the tellinid bivalve Macoma nasuta. The exhalent siphon is located close to the transparent wall, while the inhalant siphon can be seen occasionally in the background. While feeding, water is pumped out through the exhalent siphon as can be seen from the movement of sediment particles. After 17 seconds the animal expels sediment through its inhalant siphon (pseudofeces expulsion). The last sequence is a defecation event causing sediment failure and creating a new sedimentary channel. Sediment spheres are fecal pellets that have accumulated over time. Video is shown in real time and 50-fold speed.

 

Oxygen dynamics associated with hydraulic activities of the thalassinid crustacean Neotrypaea californiensis. Shown are effects of burrowing and burrow ventilation in muddy and sandy sediments. In the low permeability muddy sediment oxygen penetration
is limited by diffusion and oxygen is only detected where the burrow is in direct contact with the oxygen-sensitive foil. In the permeable sandy sediment burrow ventilation results in advective transport of oxygen through the sediment surrounding the burrow and oxygen
penetrates several centimeters from the burrow into the surrounding sediment. Video is shown at 2500-fold speed (24 hours in 34 seconds).

 

Oxygen dynamics in permeable sediment inhabited by lugworms. Experiments were conducted in a flume tank (tank dimensions 140×26×24 cm, with a 50×24 oxygen sensitive foil). White line depicts the sediment surface, which is structured by defecation mounds and feeding funnels of the lugworms. Sixteen adult lugworms were allowed to establish burrows in the tank. Oxygen dynamics at depth are driven bioadvection induced two lugworms that ventilated and burrowed close to the oxygen sensitive foil. Increased current velocities above the sediment induced deeper oxygen penetration into the surficial sediment driven by passive bioirrigation, i.e., due to the interaction between the unidirectional flow of overlying water and animal-induced sediment topography. In concert passive and active bioirrigation result in very dynamic oxygen distributions within the permeable sediment. Video is shown at 100-fold speed (2.5 hours in 90 seconds).

 

Effects of hydraulic activities by a small community of benthic infauna on porewater transport in permeable sediments. The community comprised a razor clam, a nereid polychaete and eight maldanid polychaetes. Porewater flow patterns were visualized by
following the pathway of an inert tracer (fluorescein, green color) injected into the sediment at 9 locations. Porewater pressure dynamics were recorded simultaneously at 2 different locations (indicated by white and blue dots) through the side wall of the aquarium. Increased porewater pressure coincides with upward movement of the tracer. Video is shown at 1000-fold speed (6 hours in 22 seconds).

 

Compilation of oxygen dynamics in permeable sediments induced by biohydraulically active organisms. Video is shownat 1000-fold speed.

 

Oxygen dynamics associated with hydraulic activities of the thalassinid crustacean Neotrypaea californiensis. Shown is an overlay of time-lapse photographs and oxygen images taken from opposite sides of a thin aquarium. The hydraulic activities of the
thalassinid at different locations within the burrow cause distinct oxygen dynamics around the burrow as well as movements of the oxicanoxic boundary at the sides of the aquarium. The latter movements were possible due to a leaking sealing gasket and water surrounding
the sediment. Video is shown at 1000-fold speed (10 hours in 36 seconds).