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A buffet the size of the ocean!

Join researchers Alison Dominy, Sean Lu, and Ellen Winant as they compare animal abundance and heterotrophic processes in the benthos and water column. Dive into zooplankton feeding experiments and the Salp Invasion phenomenon. Discover insights on organic carbon, remineralization, and the dynamic filtration system in water column-benthic interaction.

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A buffet the size of the ocean!

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  1. A buffet the size of the ocean! The heterotroph group: Alison Dominy, Sean Lu, Ellen Winant

  2. GOALS • A. Compare animal abundance within the benthos and water column. • B. Investigate heterotrophic processes that influence rates of exchange of matter and energy between the water column and the benthos.

  3. Zooplankton Feeding Experiment • Unusually high rates of ingestion and volume swept clear (VSC).

  4. starved Ingestion rate Volume Swept Clear unstarved Phytoplankton Concentration Phytoplankton Concentration Dataand the Studies Top graph redrawn from Frost, 1972. Bottom graph redrawn from Redrawn from Paffenhofer and Lewis, 1990

  5. THE Salp Invasion! Oh Noes! Is the beginning stage of an upwelling an optimal environment for Salp (Thaliacea) growth? -Colder temperatures. -Slight increase in nutrient concentration. -Little competition with copepods for food. Salps asexually reproducing -Leads to increased Organic Carbon……

  6. Comparison of Animal Density within Cores to Zooplankton within the Water Column “As a life’s work, I would remember everything-everything, against loss. I would go through life like a plankton net.” – Annie Dillard -Well, if Annie was to go through life with our plankton net, she would miss a wealth of information. Sampling with our 500 micromesh excluded many of the smaller plankton-an order of magnitude to be precise.

  7. Benthos Animal Density Mean number of benthic organisms at R2 = 833 individuals / m2. Based on literature values, zooplankton abundance in the water column is at least an order of magnitude greater.

  8. Core Analysis • Cores were taken for fine sediment, chlorophyll, and ammonium analysis • Samples taken every 1 cm for fine sediment and chlorophyll analysis.

  9. Sediment Fines We might expect lower organic material because of greater mineralization rates Possible higher levels of inorganic fines because less mixing

  10. Ammonia Concentration within the Pore Water Late Summer- at 27 meters in SAB R. Jahnke et al. 2005. June 2008- at 27meters in SAB

  11. Remineralization Estimates • -Remineralization is highest in the upper cm’s of the sediment. • -Amount of carbon found in the sediment was less than Jahnke’s findings.

  12. An overview of water column and benthos rates CO2 NH4 CO2 NH4 ? Primary Productivity Zooplankton grazing e.g. Eucalanus pileatus only 16 ugC/ind./d 679 mgC/m2/d WATER COLUMN BENTHIC SEDIMENTS >700 mgC/m2/d 78.6 mgC/m2/d Organic matter CO2 NH4 CO2 NH4 Primary Productivity Remineralization Decompostion

  13. The Water Column andBenthicInteraction An Open and Dynamic Filtration System Organic carbon input from the water column (from organisms such as (eucalanus pileatus)+ tidal and current-bottom interactions  remineralization within the sediment by heterotrophic bacteria  inorganic carbon and nitrogen advected back out due to tidal current-bottom interactions/ripples.

  14. Conclusions • Unusually high feeding for Eucalanus suggesting low food concentration and high abundance of salp support the upwelling hypothesis. • Low rates remineralization relative to primary production suggest that the system is not in steady state. Remineralization rate may increase later as production subsides.

  15. “GOODBYE”

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