Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

This dataset contains sediment grain size, mean sediment grain size and sorting values (sigma)

Related datasets:
Benthic macrofaunal abundance
Macrofauna species distribution
Phytoplankton cell count
Sediment fauna and plastic
Water chemistry

Samples collected in a perimeter of ~1 km offshore of the discharge channel (33°08'18.9"N 117°20'21.3"W).
Bottom samples collected at depth range 4m – 17m

Samples were collected in four trips:
Pre-discharge: Dec 2nd-4th 2014 and Sep 21st-24th 2015.
Post-discharge: May 9th-12th 2016 and Nov 8th-11th 2016

Transect lines were deployed going from the discharge channel (Outflow) and the Intake to 1000 m offshore. Sampling was done every 25 m until 200 m offshore, then at 400, 600, 800 and 1000 m (“stations”). The “Parallel” transect ran continuous parallel to the beach ~200 m offshore and samples stations were deployed every ~100 m. Station 1 is the southern-most sampling point (south of discharge channel). At each station surface (~1 m depth) and bottom water samples were taken and a sediment sample.

The benthic surveys were done continuously at the first 200 m offshore if water conditions allowed. At station 400, 600, 800 and 1000 and on the parallel stations, 10 1x1m quadrates were deployed.

Sediment analysis:

300-500 g of sediment was collected at certain stations. The sediment was kept at -20 degC. Upon analysis, the sediment was thawed and rinsed in 90% ethanol.

The ethanol was obtained and surveyed through a microscope to count the organisms present. The counted individuals were summed and normalized to the weight of the sample.

The sediment was dried and weighed and the grain size analyzed through sieving Sieving pots ranging from +0.5 Φ Phi to +4.75 Φ Phi (+0.5 being bigger particles and +4.75 being smaller) were used. A weighted amount of sediment (between 75-90 g) was stirred for 15 min. and the amount of sediment in each pot was weighted (Folk 1966).

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date
- renamed parameters to BCO-DMO standard
- sorted data by date
- transposed data to fit BCO-DMO formatted rows and columns

Version 1: 2015-08-03
Version 2: 2015-08-11 (added lat_site/lon_site for mapping purposes)
Version 3: 2016-09-21 (added 2015 data)
Version 4: 2017-09-22 (revised 2014 data and added 2016 data)

Description from NSF award abstract:
Desalination of seawater accounts for a worldwide water production of about 70 million cubic meters per day. Despite the many benefits the technology has to offer, there are concerns over potential negative impacts on the environment. A key issue that has not been thoroughly investigated is the impact of effluent discharge on coastal marine ecosystems. This project will provide quantitative scientific assessment of the potential impacts of effluent discharge on coastal ecosystems in California and assess how such data influences public perception and public policy. The team of social and natural scientists has experience related to coastal pollution, California coastal ecology, marine biogeochemistry, toxicology, environmental policy and economics, water policy and management, and utility-stakeholder communications. Established relations with desalination facilities in California will ensure an integrative framework for research on the human and environmental aspects related to the increasing abundance of desalination facilities along the California coast, and contribute to both securing freshwater resources and sustaining productive and healthy coastal communities and coastal environments.

The objectives of this project are to (1) determine how effluent discharges from facilities for seawater desalination by reverse osmosis affect key organisms of the California coastal ecosystem with implications for ecosystem structure and function, (2) describe the spatial extent of the effect for different discharge schemes, and (3) evaluate how results from this and similar environmental impact studies influence public perception and decision making regarding desalination plant construction and operation. The project will combine in situ field chemical and biological measurements, controlled laboratory experiments, and assessments of how people and organizations interpret and use this data for making environmentally sound and sustainable decisions. Field studies will be performed at three different desalination plants to identify and quantify the possible effects of stressors associated with effluent discharge on local biota. Observed effects will be validated through controlled laboratory bioassay experiments. The scientific results will be communicated to the general public and decision makers to assess how scientific data is used by different stakeholders.

This project is supported under NSF's Coastal SEES (Science, Engineering and Education for Sustainability) program.