sea grass bed in South and what were the pressures on the seagrass - - PowerPoint PPT Presentation

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sea grass bed in south
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sea grass bed in South and what were the pressures on the seagrass - - PowerPoint PPT Presentation

Jul 23, 2023 113 likes •441 views

How the Zostera noltii sea grass bed in South and what were the pressures on the seagrass habitat during Dublin Bay changed this period? over the summer of 2019 Carbon sequestration 35 times quicker than rainforest Sediment

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How the Zostera noltii sea grass bed in South Dublin Bay changed

  • ver the summer of

2019

and what were the pressures on the seagrass habitat during this period?

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Why is it important?

  • Carbon sequestration
  • 35 times quicker than rainforest
  • Sediment trapping
  • Prevents erosion
  • Nursery ground for other species
  • Shrimps, small fish
  • Food for Brent Geese
  • Nutritious, protein rich
  • Water quality indicator in the Water Framework

Directive

  • Indicative of water quality
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Feeding on the seagrass

Brent Geese

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Zostera noltii seagrass on Merrion strand

  • First official record: 1954
  • In 1983 approx. 1.4 ha
  • In 1993 approx. 1.75 ha starting 10-20 m

from the seawall protecting houses

  • In July 2019 approx. 1.8 ha starting 5 m

from the seawall

  • One of only two locations in the Dublin area
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Blackened brittle blades in the seagrass bed

Heat stress

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Unhealthy seagrass envrionment Healthy seagrass environment

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Green opportunistic seaweed

  • Grows in long strands attached to a razorfish shell or a cockle
  • The loose end of the strand floats freely in the high tide
  • Unattached seaweed and other loose debris get attached to the strand
  • When the strand gets too heavy it breaks free and floats off with the tide
  • When the tide recedes again the seaweed mould descends on the sediment
  • Anaerobic conditions occur
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Anaerobic sediment

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Direct Disturbance

People & Dogs Vehicles Litter

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Sewage overflow

Sanitary litter Can cause nutrient enrichment

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Theme 1: Strengthen the knowledge base of decision- makers for the conservation and management of biodiversity, and protect species and habitats of conservation value within Dublin City

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Act ctio ion 2: Continue to map the distribution, and assess the abundance and conservation status

Recommendations:

  • Yearly survey of the Zostera noltii bed
  • Intertidal mudflat temperature measurement during heatwaves and

development of anaerobic mud, and fate of mud snails (Hydrobia spp.)

  • Sediment samples taken for analysis
  • Measurement of nutrient levels in the freshwater stream
  • Monitoring of the growth of Salicornia europaea and the formation of a new

lagoon

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Actio ion 3: Develop site-specific best management guidelines for legally protected species within Dublin City, and communicate with landowners and users

Recommendations:

  • Design and put up new signage in locations closer to the seagrass bed
  • involve the Sandymount and Merrion Residents association and local residents,

as they are very knowledgeable and interested in protecting the Zostera noltii bed.

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Thank you !

Rita Hagan rhagan100@gmail.com 087-7512955