{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/22015"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/22015","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"An analysis of factors controlling the distribution of zooplankton in the Knysna estuary, South Africa","abstract":"The Knysna estuary system, on the south coast of South Africa, was sampled for zooplankton over period of one year. All species were recorded and an attempt was made at relating the distribution of populations to physical factors within the estuary. Over 50 species were identified. Pseudodiaptomus hessei, Acartia(Paracartia) longipatella and A.(Acartiella) natalensis were the dominant copepods in the upper estuary. Paracalanus spp. were dominant near the mouth. Zooplankton distribution was found to be related to tidal exchange. The zooplankton displayed a seasonal cycle of abundance, with maximum numbers occuring during summer. P. hessei displayed no pronounced seasonal cycle in abundance. Its abundance was strongly related to freshwater inflow. Seasonal succession was evident between A. natalensis, the summer dominant, and A. longipatella, the winter dominant. The controlling factors for this cyclical dominance were not clear. Diel vertical migration behaviour was shown to various degrees by virtually all zooplankton populations. The stimulus for this behaviour could not be definitely identified.","abstract_html":"The Knysna estuary system, on the south coast of South Africa, was sampled for zooplankton over period of one year. All species were recorded and an attempt was made at relating the distribution of populations to physical factors within the estuary. Over 50 species were identified. Pseudodiaptomus hessei, Acartia(Paracartia) longipatella and A.(Acartiella) natalensis were the dominant copepods in the upper estuary. Paracalanus spp. were dominant near the mouth. Zooplankton distribution was found to be related to tidal exchange. The zooplankton displayed a seasonal cycle of abundance, with maximum numbers occuring during summer. P. hessei displayed no pronounced seasonal cycle in abundance. Its abundance was strongly related to freshwater inflow. Seasonal succession was evident between A. natalensis, the summer dominant, and A. longipatella, the winter dominant. The controlling factors for this cyclical dominance were not clear. Diel vertical migration behaviour was shown to various degrees by virtually all zooplankton populations. The stimulus for this behaviour could not be definitely identified.","abstract_has_math":false,"creators":["Veldhuis, Helen Anne"],"institution":"Department of Biological Sciences","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Griffiths, Charles L"],"committee_chairs":[],"committee_members":[],"year":1987,"date_issued":"1987","date_published":"1987","updated_at":"2026-07-22T22:23:42Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/22015","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Griffiths, Charles L"]},{"key":"dc:creator","label":"Author","values":["Veldhuis, Helen Anne"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-09-29T17:15:44Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-09-29T17:15:44Z"]},{"key":"dc:date.issued","label":"Date","values":["1987"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Biological Sciences"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MSc"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/22015"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The Knysna estuary system, on the south coast of South Africa, was sampled for zooplankton over period of one year. All species were recorded and an attempt was made at relating the distribution of populations to physical factors within the estuary. Over 50 species were identified. Pseudodiaptomus hessei, Acartia(Paracartia) longipatella and A.(Acartiella) natalensis were the dominant copepods in the upper estuary. Paracalanus spp. were dominant near the mouth. Zooplankton distribution was found to be related to tidal exchange. The zooplankton displayed a seasonal cycle of abundance, with maximum numbers occuring during summer. P. hessei displayed no pronounced seasonal cycle in abundance. Its abundance was strongly related to freshwater inflow. Seasonal succession was evident between A. natalensis, the summer dominant, and A. longipatella, the winter dominant. The controlling factors for this cyclical dominance were not clear. Diel vertical migration behaviour was shown to various degrees by virtually all zooplankton populations. The stimulus for this behaviour could not be definitely identified."]},{"key":"dc:title","label":"Title","values":["An analysis of factors controlling the distribution of zooplankton in the Knysna estuary, South Africa"]}]}],"canonical_facts":{"dc:contributor.advisor":["Griffiths, Charles L"],"dc:creator":["Veldhuis, Helen Anne"],"dc:date.accessioned":["2016-09-29T17:15:44Z"],"dc:date.available":["2016-09-29T17:15:44Z"],"dc:date.issued":["1987"],"dc:description.abstract":["The Knysna estuary system, on the south coast of South Africa, was sampled for zooplankton over period of one year. All species were recorded and an attempt was made at relating the distribution of populations to physical factors within the estuary. Over 50 species were identified. Pseudodiaptomus hessei, Acartia(Paracartia) longipatella and A.(Acartiella) natalensis were the dominant copepods in the upper estuary. Paracalanus spp. were dominant near the mouth. Zooplankton distribution was found to be related to tidal exchange. The zooplankton displayed a seasonal cycle of abundance, with maximum numbers occuring during summer. P. hessei displayed no pronounced seasonal cycle in abundance. Its abundance was strongly related to freshwater inflow. Seasonal succession was evident between A. natalensis, the summer dominant, and A. longipatella, the winter dominant. The controlling factors for this cyclical dominance were not clear. Diel vertical migration behaviour was shown to various degrees by virtually all zooplankton populations. The stimulus for this behaviour could not be definitely identified."],"dc:identifier.uri":["http://hdl.handle.net/11427/22015"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Biological Sciences"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["An analysis of factors controlling the distribution of zooplankton in the Knysna estuary, South Africa"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MSc"]},"updated_at":"2026-07-22T22:23:42Z"}