Algal BioSciences
Integrated Approach to Seaweed Resource Assessment
Tom Rossiter1,2, Thomas Furey2 , Gema Casal2 , Tim McCarthy3 , Dagmar B Stengel1
1Botany and Plant Science, School of Natural Sciences, Ryan Institute for Environmental, Marine and
Energy Research, National University of Ireland Galway, Galway, Ireland
2INFOMAR, Marine Institute, Rinville, Co Galway, Ireland
3NUI Maynooth, Ireland
Project Objectives
Development of an innovative, multidisciplinary and
integrated approach to intertidal and sub-tidal seaweed
resource assessment
1) Best practice resource assessment methodologies
2) Inform on sustainable development of Irish seaweed resources
3) Contribute to coastal zone management and spatial planning
Background
• Seaweeds play an important ecological role in Irish coastal systems
• Increased demand for seaweed products is leading to increased economic activity
• Need for a baseline assessment of commercially and ecologically important
species
Questions/Challenges
Data:
Approach:
Considerations:
Knowledge & data gap
Resolution & scale
Standardised approach
Repeatability & reliability
Technology application
Cost effective resource
assessment
Stakeholder interests
(Industry, Harvesters, Academia,
Licensing)
Ascophyllum nodosum
Kelp species
(Laminaria digitata pictured)
Acoustic Remote Sensing
Source: INFOMAR
Source: INFOMAR/Fabio Sacchetti
Multibeam
Echosounder
Singlebeam
Echosounder
Source: Mac Craith & Hardy (2015)
Optical Remote Sensing
Multispectral –
High spatial, low spectral resolution
Hyperspectral –
High spatial and spectral resolution
Both systems can be mounted on a range
of platforms
Limited by water conditions and depth
Source: Govender et al., (2007)
Hyperspectral mapping – Heligoland, Germany
Source: Oppelt et al. (2012)
Pilot Study
Survey plane…
…or bird
Study site:
Great Man’s Bay
&
Inner reaches of Kilkieran Bay
Aerial survey flight conducted:
• Flight plan designed to cover as much
of the coastline as possible
• Flight conducted by Air Survey and
National Centre for Geocomputation
(NUIM)
Source: Air Survey
Flight Details
Average flight height: 600m
Cameras/sensors used: Thermal, RGB
Hyperspectral - OCITM-U-1000
Ultra-Compact Hyperspectral
Imager
• 100 bands (8 rows per band)
• Spectral range 600-100nm
Multispectral – AIRINOV AgroSensor
• 4 channels selected for
agriculture
• Bands used – green, red, near
infrared and infrared
Flight RGB
ESRI World
Imagery
Initial Data Output
(Multispectral)
Study Sites
Ground-truth data
Fieldwork
8 fieldwork sites within wider study area:
• 5 completed
Transect and quadrat methodology:
• Transects randomly spaced
• 5 quadrats (1m²) per transect
• Q1, Q3, Q5 sampled for wet-weight biomass
Data also collected on:
• Percent cover
• Average frond length (cm)
• Stipe/Holdfast density (/m²)
TriOS RAMSES radiometer
Biomass
Limited research on using remote sensing to assess intertidal macroalgal biomass
• Much of the literature appears to focus on terrestrial vegetation
Scaling up in-situ biomass estimates to the spatial extent defined by remote
sensing:
• Invasive brown algae on Tahitian coral reefs - Andréfouët et al (2004)
• Remote sensing of seagrass - Armstrong (1993)
• Remote sensing of brown seaweed distribution and biomass - Guillaumont et al (1993)
Identifying relationship between biomass and spectral response:
• Remote sensing of seagrass distribution in Bourgneuf Bay - Barillé et al (2009)
Challenges
A. nodosum beds within Kilkieran Bay are not homogenous
Makes A. nodosum discrimination more difficult
Need of very high spatial resolution to visually identify species
Spectral discrimination between species of the same
group remains a challenge
What next?
Completion of fieldwork survey and analysis of data
• Identify morphometric/biomass relationships
• Understanding of the characteristics of seaweed assemblages in
Kilkieran Bay
Processing, classification and analysis of multispectral and hyperspectral
data with help from NUIM
• Training with multispectral on software such as ENVI
• Once trained begin work on the hyperspectral
Creation of distribution and biomass map of A. nodosum within
Kilkieran Bay
Acoustic survey of kelp distribution and biomass
Algal BioSciences
Thank you