ZOOSCANNING THE CCZ: A BASELINE STUDY OF ZOOPLANKTON ASSEMBLAGES IN THE CLARION CLIPPERTON ZONE
Date
2024
Authors
Contributor
Advisor
Department
Instructor
Depositor
Speaker
Researcher
Consultant
Interviewer
Narrator
Transcriber
Annotator
Journal Title
Journal ISSN
Volume Title
Publisher
Volume
Number/Issue
Starting Page
Ending Page
Alternative Title
Abstract
Zooplankton, small animals that inhabit the water column, are the dominant secondary producers of the global ocean. They serve several important roles in food web dynamics and ecosystem function but may be at risk due to the emerging industry of deep-sea mining. This study examines deep-sea plankton within the Clarion Clipperton Zone (CCZ), a region of the eastern tropical Pacific (ETP) that is rich in polymetallic nodules, as part of a baseline survey of ecosystem function prior to mining impact. Samples were collected over the NORI-D exploration mining claim using a 1m² Multiple Opening and Closing Net and Environmental Sensing System (MOCNESS) on two cruises in 2021, and samples were analyzed using a Hydroptic ZooScan MIV system. Zooplankton abundance was highest in the well-oxygenated upper 100 m of the water column, with lower abundance within the midwater oxygen minimum zone (OMZ) as well as below the OMZ. The expected migratory behavior for zooplankton is to move from the mesopelagic into the upper ocean at night. Most of the samples analyzed from the fall (DG5C cruise) exhibited this trend in all size fractions, but the large size fraction from the spring (DG5B cruise) did not. Seasonal variability in zooplankton abundance was observed in all regions of the water column (Upper, OMZ, Below OMZ) at the preservation reference zone (PRZ) site, with more small (0.2-1.0 mm) and large (1.0-5.0 mm) animals in the spring compared to the fall. At the collector test area (CTA) site, significant seasonality was observed only within the core of the OMZ in the small and large size fractions, with higher zooplankton abundance in spring. These site-specific differences in the strength of seasonality may have been due to higher oxygen concentrations in the upper portion of the OMZ during spring (100-300 m). This study provides some of the first information on zooplankton seasonality across midwater in the Eastern Tropical Pacific: In providing baseline observations, this work also enables subsequent study of how zooplankton are impacted by commercial mining in this region. The information gathered with the study could be used to help set industry regulations to protect zooplankton communities from deep-sea mining impacts.
Keywords: Zooplankton, ZooScan, Deep-sea mining, eastern tropical Pacific (ETP), Clarion Clipperton Zone (CCZ), oxygen minimum zones (OMZ), seasonality
Description
ABSTRACT
Zooplankton, small animals that inhabit the water column, are the dominant secondary producers of the global ocean. They serve several important roles in food web dynamics and ecosystem function but may be at risk due to the emerging industry of deep-sea mining. This study examines deep-sea plankton within the Clarion Clipperton Zone (CCZ), a region of the eastern tropical Pacific (ETP) that is rich in polymetallic nodules, as part of a baseline survey of ecosystem function prior to mining impact. Samples were collected over the NORI-D exploration mining claim using a 1m² Multiple Opening and Closing Net and Environmental Sensing System (MOCNESS) on two cruises in 2021, and samples were analyzed using a Hydroptic ZooScan MIV system. Zooplankton abundance was highest in the well-oxygenated upper 100 m of the water column, with lower abundance within the midwater oxygen minimum zone (OMZ) as well as below the OMZ. The expected migratory behavior for zooplankton is to move from the mesopelagic into the upper ocean at night. Most of the samples analyzed from the fall (DG5C cruise) exhibited this trend in all size fractions, but the large size fraction from the spring (DG5B cruise) did not. Seasonal variability in zooplankton abundance was observed in all regions of the water column (Upper, OMZ, Below OMZ) at the preservation reference zone (PRZ) site, with more small (0.2-1.0 mm) and large (1.0-5.0 mm) animals in the spring compared to the fall. At the collector test area (CTA) site, significant seasonality was observed only within the core of the OMZ in the small and large size fractions, with higher zooplankton abundance in spring. These site-specific differences in the strength of seasonality may have been due to higher oxygen concentrations in the upper portion of the OMZ during spring (100-300 m). This study provides some of the first information on zooplankton seasonality across midwater in the Eastern Tropical Pacific: In providing baseline observations, this work also enables subsequent study of how zooplankton are impacted by commercial mining in this region. The information gathered with the study could be used to help set industry regulations to protect zooplankton communities from deep-sea mining impacts.
Keywords: Zooplankton, ZooScan, Deep-sea mining, eastern tropical Pacific (ETP), Clarion Clipperton Zone (CCZ), oxygen minimum zones (OMZ), seasonality
Keywords
Citation
Extent
Format
Geographic Location
Time Period
Related To
Related To (URI)
Table of Contents
Rights
http://rightsstatements.org/vocab/InC/1.0/
Yamada, Michael
Yamada, Michael
Rights Holder
Local Contexts
Collections
Email libraryada-l@lists.hawaii.edu if you need this content in ADA-compliant format.