WAMSI 2 - Kimberley Node - 2.2.4 - Benthic primary productivity: Production and herbivory of seagrasses, macroalgae and microalgae [dataset]

Author Identifiers

Gary Kendrick

ORCID: 0000-0002-0276-6064

Christin Sawstrom

Scopus ID: 15760817000

Collection Type


Upload Date


School or Research Centre

School of Science


Western Australian Marine Science Institution (WAMSI) project funded by Western Australian State Government and research partners.


This research addressed seagrass, macroalgal and microalgal abundance, biomass and productivity for the Sunday Island Group (in the Buccaneer Archipelago, Western Australia) and also assessed rates of herbivory on seagrass. The main aim was to understand the role of benthic primary producers in the macrotidal fringing reef and terraced lagoon environments which characterize the Sunday Island Group and are common throughout the Kimberley.

Our study was focused on the islands and coastline of the Bardi Jawi Indigenous Protected Area (IPA), encompassing Cygnet Bay, One Arm Point, Jalan (Tallon Island) and Iwany (Sunday Island). Five surveys were conducted between November 2013 to November 2015, with three surveys occurring just prior to the wet season (November 2013, October 2014 and October-November 2015) and two surveys just after the wet season (March 2014 and April 2015).

Notes: Researchers have worked with Bardi Jawi Marine Rangers at One Arm Point.

Geographic bounding :

North bound: -16.30000, West bound: 123.00000, East bound: 123.30000, South bound:-16.50000

Additional Information

Seagrass production, biomass and phenology

Four fieldtrips have been undertaken (November 2013, April 2014, Oct 2014 and April 2015).

Spatial variation in biomass and productivity were measured in the two dominate seagrass species (Thalassia hemprichii and Enhalus acoroides). Five sites (C, D, E, F, G) were chosen to measure Thalassia biomass and productivity while Enhalus biomass and productivity was measured at four sites (C, D, E, F; Figure 1). Additionally, the Bardi Jawi Rangers sampled two sites monthly: Tallon Island Site C (Jalarn), were Enhalus was primarly targeted; and Sunday Island Site E (Laanyi) where Thalassia was targeted.

Macroalgae production and biomass

Sargassum branches were measured at the same five sites selected for measurement of seagrass productivity in both November 2013 and April 2014. The longest Sargassum branch was measured in the field and labelled with flagging tape. Individuals were then collected between 2 and 4 days later. In the laboratory, each branch was measured, epiphytes were removed and dried weights obtained. Species identifications are pending.

Benthic microalgae

Six soft sediment sites (see thumbnail) located in Cygnet Bay (CBS, CBN), Ardyaloon Aboriginal Community at Jologo Beach (JGB) and Sunday Island (SIRW, SIF, SINool) were sampled along a transect a 6 points between the low tide and high tide marks for chlorophyll a (benthic micro-algal (BMA) biomass), pigments (BMA community composition), particulate organic carbon and nitrogen (POC/PON), sediment moisture content, sediment pore water nutrients, and sediment particle size. In addition the water column was sampled for chlorophyll a, pigments, POC/PON, total suspended material (TSM), nutrients, and salinity to quantify the potential cycling by tidal movements on BMA and phytoplanktonic communities and nutrients between the benthos and water column.

At 4 sites (CBS, CBN, JGB and SIRW) we successfully deployed benthic chambers, an automated lander system with paired light and dark chambers that autonomously measure, salinity, temperature and oxygen evolution/respiration by benthic micro algae over a defined period of time. The chambers also collect discreet water samples which are analysed for nutrients – Nitrate (NOx), Phosphate (PO4), Silicate (Si), and Ammonia (NH4). From the chamber samples and data we can determine the role microalgae play in nutrient fluxes between the sediment and overlying water and oxygen flux as a proxy for primary production.

Microbial cycling

- Sampling sites and analyses

Four reef flat sites on Sunday Island (C, D, E, F), with a transect at each site including benthic habitats from (I) mangrove, (II) seagrass and (III) bare sediment, were sampled for bacterial carbon production (BCP) and utilisation, and concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN). In addition surface water samples were obtained at the edge of the reef flat and bioassays were set up to provide estimates of the biodegradability of the DOC and TDN pool. Fluxes of DOC and TDN between benthic and pelagic habitats were analysed in water samples obtained from benthic chambers deployed for 2 ½ hrs in the middle of the day in Cygnet Bay. At each site, samples were taken for the molecular analysis of microbial community structure using ARISA. In particular the community structure and abundance of ammonia oxidising (nitrifying) bacteria and archaea were analysed, using microarray and quantitative-PCR, respectively. Corresponding ammonia oxidation (nitrification) rate measurements were also made. Finally, samples for the analysis of chlorophyll-a and photopigments were taken, and each site was analysed for sediment biogeochemistry and physical parameters (C and N isotopic composition; sediment grain size; water content; porewater nutrients).

Stable isotopes

Samples were collected and processed for analysis of stable isotopes for the following taxa: Thalassia, Enhalus, Cymodocea, Thalassodendron, Sargassum, Hormophysa and Turbinaria. The samples have been submitted to the Western Australian Biogeochemistry Centre for analysis.


At each of the sites surveyed, CTD (conductivity, temperature, depth) and PAR (photosynthetically active radiation) sensors were deployed for the duration of the over which seagrass growth was integrated. These data have been downloaded, and quality control and data analysis is ongoing.

Data URLs

Access record on the Australian Ocean Data Network here

Access related CSIRO Marlin record here

Research Activity Title

WAMSI - Kimberley Node - 2.2.4 - Benthic primary productivity: production and herbivory of seagrasses, macroalgae and microalgae

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Creative Commons License

Creative Commons Attribution-No Derivative Works 2.5 Australia License
This work is licensed under a Creative Commons Attribution-No Derivative Works 2.5 Australia License.