Knowledge Base

The Knowledge Base provides access to information about the environmental effects of marine and wind energy, supporting OES-Environmental and WREN initiatives. Relevant documents and OES-Environmental metadata forms are compiled into a user-friendly table with advanced filtering. Filters may be selected on the right, or keywords entered in the Search Text box. Content may also be sorted alphabetically by clicking on column headers. More entries will load as you scroll down.


As an alternative to the Knowledge Base, check out the Map Viewer to access geotagged content in a spatial view.


Title Author*sort descending Date** Type of Content Technology Types Stressors Receptors
Pacific Continental Shelf Environmental Assessment (PaCSEA): Aerial Seabird and Marine Mammal Surveys off Northern California, Oregon, and Washington, 2011-2012 Adams, J., et al. March 2014 Report N/A N/A Birds, Marine Mammals, Cetaceans, Pinnipeds
Request for advice about the displacement of marine mammals around operational offshore windfarms Alcock, P. October 2012 Report Wind Energy (General), Offshore Wind Displacement, Noise Marine Mammals, Cetaceans
A Framework for Regulating Underwater Noise During Pile Driving Andersson, M., et al. August 2017 Report Wind Energy general, Offshore Wind Noise Fish, Marine Mammals
Impacts of Wind Energy Facilities on Wildlife and Wildlife Habitat Arnett, E., et al. September 2007 Report Wind Energy general Static Device Bats, Birds, Fish, Marine Mammals, Nearfield Habitat
Long-range Effects of Airgun Noise on Marine Mammals: Responses as a Function of Received Sound Level and Distance Bain, D., Williams, R. May 2006 Report N/A Noise Marine Mammals
Seismic Survey Mitigation Measures and Marine Mammal Observer Reports Barkaszi, M., et al. June 2012 Report N/A Noise Marine Mammals, Cetaceans
California Current Cetacean & Ecosystem Assessment Survey (CalCurCEAS): Final Report to Bureau of Ocean Energy Management Regarding Surveys of Windfloat and Wave Energy Areas Barlow, J., Henry, A., Ballance, L. April 2014 Report Marine Energy general, Wave, Wind Energy general, Offshore Wind N/A Ecosystem, Marine Mammals, Cetaceans
Standard Investigation of the Impacts of Offshore Wind Turbines on the Marine Environment (StUK3) Bellebaum, J., et al. February 2007 Report Wind Energy general, Offshore Wind Static Device Birds, Fish, Marine Mammals, Nearfield Habitat
Understanding the Potential for Marine Megafauna Entanglement Risk from Marine Renewable Energy Developments Benjamins, S., et al. January 2014 Report Marine Energy (General), Wind Energy (General), Offshore Wind Entrapment, Habitat Change Marine Mammals, Cetaceans
The Effects of Wind Power on Marine Life - A Synthesis Bergström, L., et al. October 2012 Report Wind Energy general, Offshore Wind N/A Fish, Marine Mammals
Measurement of Wind Turbine Construction Noise at Horns Rev II Betke, K. December 2008 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Monitoring and Research Shortlist Offshore Wind - Knowledge advancements and follow up Boon, A. January 2012 Report Wind Energy general, Offshore Wind Noise Birds, Seabirds, Fish, Marine Mammals
Prevention of the ecological effects of offshore windfarms in licensing and spatial planning - an overview Boon, A. July 2012 Report Wind Energy general, Offshore Wind Static Device Birds, Seabirds, Fish, Marine Mammals
Monitoring and Researching Ecological Effects of Dutch Offshore Wind Farms Boon, A., et al. May 2010 Report Wind Energy general, Offshore Wind N/A Bats, Birds, Fish, Marine Mammals, Socio-economics
A methodological update of the Framework for the Appropriate Assessment of the ecological effects of Offshore Windfarms at the Dutch Continental Shelf Boon, A., et al. July 2012 Report Wind Energy general, Offshore Wind Noise, Static Device Birds, Seabirds, Fish, Marine Mammals
A Protocol for Implementing the Interim Population Consequences of Disturbance (PCoD) approach: Quantifying and Assessing the Effects of UK Offshore Renewable Energy Developments on Marine Mammal Populations Booth, C., et al. November 2013 Report Marine Energy general, Wind Energy general N/A Marine Mammals
Argyll Array Windfarm Basking Shark Draft Chapter for Environmental Statement Booth, C., King, S., Lacey, C. January 2013 Report Wind Energy general, Offshore Wind Dynamic Device Marine Mammals
The Effects of Anthropogenic Sound on Marine Mammals Boyd, I., et al. June 2008 Report Marine Energy general, Wind Energy general, Offshore Wind Noise Marine Mammals, Cetaceans
Investigations into the effects of pile driving at the offshore wind farm Horns Rev II and the FINO III research platform Brandt, M., Diederichs, A., Nehls, G. July 2009 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Effects of Offshore Pile Driving on Harbour Porpoise Abundance in the German Bight: Assessment of Noise Effects Brandt, M., et al. June 2016 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Habitat Preferences of Harbour Seals in the Dutch Coastal Area: Analysis and Estimate of Effects of Offshore Wind Farms Brasseur, S., et al. January 2012 Report Wind Energy general, Offshore Wind Noise Marine Mammals, Pinnipeds
Marine Mammal Monitoring Plan: San Francisco Oakland Bay Bridge East Span Seismic Safety Project Caltrans February 2004 Report N/A Noise Marine Mammals, Pinnipeds
Compliance Monitoring Of Underwater Blasting For Rock Removal At Warrior Point, Columbia River Channel Improvement Project Carlson, T., et al. May 2011 Report N/A Noise Birds, Seabirds, Fish, Marine Mammals
A Characterization of Marine Mammals and Turtles in the Mid and North Atlantic Areas of the US Outer Continental Shelf Cetacean and Turtle Assessment Program June 1981 Report N/A N/A Marine Mammals, Cetaceans, Reptiles
Humpback Whale Encounter with Offshore Wind Mooring Lines and Inter-Array Cables Copping, A., Grear, M. October 2018 Report Wind Energy (General), Offshore Wind Entrapment Marine Mammals, Cetaceans
Danish Offshore Wind Key Environmental Issues - A Follow-up Danish Energy Agency, et al. February 2013 Report Wind Energy general, Offshore Wind N/A Birds, Seabirds, Fish, Marine Mammals
Offshore Wind Farms and the Environment: Danish Experiences from Horns Rev and Nysted Danish Energy Authority November 2006 Report Wind Energy general, Offshore Wind N/A Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Socio-economics
Potential Impacts of Ocean Energy Development on Marine Mammals in Oregon Davis, A. December 2012 Report Marine Energy general, Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans
Underwater Radiated Noise Due to the Piling for the Q7 Offshore Wind Park de Jong, C., Ainslie, M. June 2008 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Offshore Wind Farms in the Belgian Part of the North Sea: State of the Art After Two Years of Environmental Monitoring Degraer, S., Brabant, R. January 2009 Report Wind Energy general, Offshore Wind N/A Birds, Ecosystem, Fish, Invertebrates, Marine Mammals
Offshore Wind Farms in the Belgian Part of the North Sea: Early Environmental Impact Assessment and Spatio-Temporal Variability Degraer, S., Brabant, R., Rumes, B. January 2010 Report Wind Energy general, Offshore Wind N/A Birds, Seabirds, Fish, Invertebrates, Marine Mammals, Socio-economics, Environmental Impact Assessment
Methodologies for measuring and assessing potential changes in marine mammal behaviour, abundance or distribution arising from the construction, operation and decommissioning of offshore windfarms Diederichs, A., et al. June 2008 Report Wind Energy general, Offshore Wind N/A Marine Mammals
Investigations of the Bird Collision Risk and the Responses of Harbour Porpoises in the Offshore Wind Farms Horns Rev, North Sea, and Nysted, Baltic Sea, in Denmark - Part II: Harbour porpoises Diederichs,A., Hennig, V., Nehls, G. January 2008 Report Wind Energy general, Offshore Wind Noise, Static Device Marine Mammals
Movements of Seals from Rødsand Seal Sanctuary Monitored by Satellite Telemetry Dietz, R., et al. January 2003 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Pinnipeds
Marine Mammals - Investigations and preparation of environmental impact assessment for Kriegers Flak Offshore Wind Farm Dietz, R., et al. June 2015 Report Offshore Wind N/A Marine Mammals, Socio-economics, Environmental Impact Assessment
Burbo Bank Extension Offshore Wind Farm Volume 2: ES Biological Environment DONG Energy March 2013 Report Wind Energy general, Offshore Wind Dynamic Device Birds, Fish, Marine Mammals
Review Report 2005: The Danish Offshore Wind Farm Demonstration Project: Horns Rev and Nysted Offshore Wind Farms Environmental Impact Assessment and Monitoring DONG Energy, Vattenfall November 2006 Report Wind Energy general, Offshore Wind EMF, Noise, Static Device Benthic Invertebrates, Birds, Fish, Marine Mammals, Socio-economics, Environmental Impact Assessment
Environmental Impacts of Offshore Wind Power Production in the North Sea Draget, E. January 2014 Report Wind Energy general, Offshore Wind N/A Benthic Invertebrates, Birds, Fish, Marine Mammals
The Number and Distribution of Marine Mammals in the Fall of Warness, Orkney July 2005 - July 2006 Duck, C., et al. August 2006 Report N/A N/A Marine Mammals, Cetaceans, Pinnipeds
Effects from the Construction of Nysted Offshore Wind Farm on Seals in Rødsand Seal Sanctuary Based on Remote Video Monitoring Edrén, S., et al. June 2004 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Pinnipeds
Potential Impacts to Predator-Prey Relationships as a Result of the Proposed Cape Wind Project in Nantucket Sound ESS Group September 2006 Report Wind Energy general, Offshore Wind N/A Birds, Seabirds, Ecosystem, Fish, Marine Mammals
Final Underwater Noise Analysis of Cape Wind Energy Project ESS Group January 2006 Report Wind Energy general, Offshore Wind Noise Fish, Marine Mammals, Sea Turtles
Fall of Warness Wildlife Observations Methodology European Marine Energy Centre February 2013 Report N/A N/A Birds, Marine Mammals
Abundance and Behaviour of Cetaceans and Basking Sharks in the Pentland Firth and Orkney Waters Evans, P., Baines, M., Coppock, J. January 2011 Report N/A N/A Fish, Marine Mammals, Cetaceans
Galloper Wind Farm Project: Environmental Statement - Chapter 14: Marine Mammals Galloper Wind Farm October 2011 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans, Pinnipeds, Socio-economics, Environmental Impact Assessment
Gunfleet Sands Offshore Wind Farm Environmental Statement GE Wind Energy January 2002 Report Wind Energy general, Offshore Wind Static Device Benthic Invertebrates, Birds, Fish, Marine Mammals, Nearfield Habitat, Socio-economics, Environmental Impact Assessment
Shortlist Masterplan Wind Aerial Surveys of Harbour Porpoises on the Dutch Continental Shelf Geelhoed, S., et al. December 2011 Report Wind Energy general, Offshore Wind N/A Marine Mammals
Ocean Wind Power Ecological Baseline Studies Final Report - Volume 3: Marine Mammal and Sea Turtle Studies Geo-Marine July 2010 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans, Reptiles
COWRIE 1.5 The Potential Effects of Electromagnetic Fields Generated by Sub-Sea Power Cables Associated with Offshore Wind Farm Developments on Electrically and Magnetically Sensitive Marine Organisms - A Review Gill, A., et al. July 2005 Report Wind Energy general, Offshore Wind EMF Benthic Invertebrates, Fish, Marine Mammals
Real-Time Monitoring for Beluga Whales (Delphinapterus leucas) in the Eagle River, Alaska using a PAMBuoy Detection System Gillespie, D., et al. May 2013 Report N/A N/A Marine Mammals, Cetaceans
Assessment of the Potential for Acoustic Deterrents to Mitigate the Impact on Marine Mammals of Underwater Noise Arising from the Construction of Offshore Windfarms Gordon, J., et al. July 2007 Report Wind Energy general, Offshore Wind Noise Marine Mammals
MR8.1 Tests of Acoustic Signals for Aversive Sound Mitigation with Harbour Seals Gordon, J., et al. July 2015 Report N/A Noise Marine Mammals, Pinnipeds
Greater Gabbard Offshore Wind Farm Environmental Statement Greater Gabbard Offshore Winds January 2005 Report Wind Energy general, Offshore Wind Noise, Static Device Birds, Farfield Environment, Fish, Marine Mammals, Nearfield Habitat, Socio-economics, Environmental Impact Assessment
Framework for Assessing Ecological and Cumulative Effects of Offshore Wind Farms: Cumulative Effects of Impulsive Underwater Sound on Marine Mammals Heinis, F., de Jong, C. April 2015 Report Wind Energy general, Offshore Wind Noise Marine Mammals, Pinnipeds
The Effect of Simulated Seal Scarer Sounds on Harbour Porpoises Hermannsen, L., Mikkelsen, L., Tougaard, J. January 2017 Report Offshore Wind Noise Marine Mammals, Cetaceans, Pinnipeds
High Resolution Video Survey of Seabirds and Mammals in the Rhyl Flats Area Hexter, R. July 2009 Report Wind Energy general, Offshore Wind N/A Birds, Seabirds, Marine Mammals
Effects of Marine Windfarms on the Distribution of Fish, Shellfish and Marine Mammals in the Horns Rev Area Hoffmann, E., et al. May 2000 Report Wind Energy (General), Offshore Wind Attraction, Avoidance, EMF, Habitat Change, Noise Fish, Invertebrates, Marine Mammals, Pinnipeds
Humber Gateway Offshore Wind Farm: Offshore ES Description of the Biological Baseline Environment Humber Gateway Offshore Wind Farm January 2005 Report Wind Energy general, Offshore Wind Static Device Benthic Invertebrates, Birds, Ecosystem, Fish, Marine Mammals
Inch Cape Offshore Wind Farm Environmental Statement Inch Cape Offshore June 2011 Report Wind Energy general, Offshore Wind N/A Birds, Farfield Environment, Fish, Marine Mammals, Nearfield Habitat, Socio-economics
Report of the Working Group on Marine Mammal Ecology (WGMME) International Council for the Exploration of the Sea April 2010 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans
Pathways of Effects for Offshore Renewable Energy in Canada Isaacman, L., Daborn, G. December 2011 Report Marine Energy (General), Wind Energy (General), Offshore Wind Avoidance, Changes in Flow, Chemicals, Collision, Displacement, EMF, Habitat Change, Lighting, Noise Birds, Fish, Invertebrates, Marine Mammals, Nearfield Habitat, Physical Environment, Reptiles, Human Dimensions
Harbour Porpoises on Horns Reef Effects of the Horns Reef Wind Farm Jakob, T., et al. November 2006 Report Wind Energy general, Offshore Wind Noise, Static Device Marine Mammals
Marine Renewable Energy: A Global Review of the Extent of Marine Renewable Energy Developments, the Developing Technologies and Possible Conservation Implications for Cetaceans James, V. November 2013 Report Marine Energy general, Wind Energy general, Offshore Wind Chemicals, EMF, Noise, Static Device Marine Mammals, Cetaceans
Large Whale Ship Strike Database Jensen, A., Silber, G. January 2004 Report N/A Dynamic Device Marine Mammals, Cetaceans
Statutory Nature Conservation Agency Protocol for Minimising the Risk of Injury to Marine Mammals from Piling Noise Joint Nature Conservation Committee August 2010 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Updated Summary of Knowledge: Selected Areas of the Pacific Coast Kaplan, B., et al. July 2010 Report Marine Energy general, Wind Energy general, Offshore Wind N/A Benthic Invertebrates, Birds, Ecosystem, Fish, Marine Mammals, Sea Turtles, Socio-economics
Effect of exposure duration to pile driving sounds on temporary hearing threshold shift in harbor porpoises (Phocoena phocoena) Kastelein, R., et al. September 2015 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Hearing thresholds of two harbor seals (Phoca vitulina) for playbacks of multiple pile driving strike sounds Kastelein, R., et al. August 2013 Report Wind Energy general, Offshore Wind Noise Marine Mammals, Pinnipeds
Hearing thresholds of a harbor porpoise (Phocoena phocoena) for playbacks of multiple pile driving strike sounds Kastelein, R., et al. August 2013 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Hearing frequencies of a harbor porpoise (Phocoena phocoena) temporarily affected by played back offshore pile driving sounds Kastelein, R., et al. September 2014 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Hearing thresholds of a harbor porpoise (Phocoena phocoena) for narrow-band sweeps (0.125-150 kHz) Kastelein, R., et al. July 2015 Report Wind Energy general, Offshore Wind Noise Marine Mammals
Ecological Survey and Impact Assessment for the Proposed Cable Route Corridor and Substation, Walpole, Lincolnshire, & Norfolk Lapwings Consultants September 2006 Report Wind Energy general, Offshore Wind Static Device Bats, Birds, Ground-Nesting Birds, Passerines, Raptors, Shorebirds, Fish, Marine Mammals, Nearfield Habitat, Terrestrial Mammals
Did the Pile Driving during the Construction of the Offshore Wind Farm Egmond aan Zee, the Netherlands, Impact Porpoises? Leopold, M., Camphuysen, K. February 2008 Report Wind Energy general, Offshore Wind Noise Marine Mammals, Cetaceans
MR6.1 Review of Methodology and Main Results of the JCP Analysis of Cetacean Densities in the Context of Marine Renewable Development Lonergan, M., Hammond, P. July 2015 Report Marine Energy general, Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans
Assessment of Basic Audiometric Functions in Killer Whales (Orcinus orca) at Loro Parque, Tenerife, Spain Lucke, K., Finneran, J., Houser, D. March 2013 Report N/A Noise Marine Mammals, Cetaceans
MR7.1.2 The Density and Behaviour of Marine Mammals in Tidal Rapids Macaulay, J., et al. July 2015 Report N/A N/A Marine Mammals
MR7.1.1 Quantifying Porpoise Depth Distributions and Underwater Behaviour in Tidal Rapids Areas Macaulay, J., et al. July 2015 Report N/A N/A Marine Mammals
NERC Knowledge Exchange: An Autonomous Device to Track Porpoise Movements in Tidal Rapids Macaulay, J., et al. November 2015 Report Marine Energy general, Tidal N/A Marine Mammals
Statistical Modelling of Seabird and Cetacean Data: Guidance Document Mackenzie, M., et al. October 2013 Report N/A N/A Birds, Marine Mammals, Cetaceans
Dogger Bank Creyke Beck Environmental Statement - Chapter 14: Marine Mammals Mackey, B., Keenan, G. March 2014 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans, Pinnipeds, Socio-economics, Environmental Impact Assessment
Approaches to Marine Mammal Monitoring at Marine Renewable Energy Developments Macleod, K., et al. August 2010 Report Marine Energy general, Wind Energy general, Offshore Wind N/A Marine Mammals
Marine Mammals and Noise: A Sound Approach to Research and Management Marine Mammal Commission March 2007 Report N/A Noise Marine Mammals, Cetaceans
Review of Environmental Data Associated with Post-Consent Monitoring of Licence Conditions of Offshore Wind Farms Marine Management Organisation April 2014 Report Wind Energy general, Offshore Wind Noise Benthic Invertebrates, Birds, Ecosystem, Fish, Marine Mammals
Modelling of Noise Effects of Operational Offshore Wind Turbines Including Noise Transmission Through Various Foundation Types Marmo, B., et al. August 2013 Report Wind Energy general, Offshore Wind Noise Fish, Marine Mammals, Pinnipeds
Interactions Between Seals and Offshore Wind Farms McConnell, B., Lonergan, M., Dietz, R. January 2012 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Pinnipeds
Understanding the Effectiveness of Acoustic Deterrent Devices on Minke Whale (Balaenoptera acutorostrata), A Low Frequency Cetacean McGarry, T., et al. November 2017 Report N/A N/A Marine Mammals, Cetaceans
Ocean Noise: Turn it down - A report on ocean noise pollution McKenna, C., International Fund for Animal Welfare June 2008 Report Marine Energy general, Wind Energy general, Offshore Wind Noise Fish, Marine Mammals
Worldwide Synthesis and Analysis of Existing Information Regarding Environmental Effects of Alternative Energy Uses on the Outer Continental Shelf Michel, J., et al. July 2007 Report Marine Energy (General), Ocean Current, OTEC, Wave, Wind Energy (General), Offshore Wind Attraction, Avoidance, Collision, Displacement, Habitat Change Birds, Fish, Invertebrates, Marine Mammals, Physical Environment, Reptiles, Human Dimensions
Continuation Implementation Masterplan Wind at Sea Ministry of Economic Affairs (Rijksoverheid), Ministry of Infrastructure and the Environment (Rijkwaterstaat) September 2015 Report Wind Energy general, Offshore Wind Noise, Static Device Bats, Birds, Fish, Marine Mammals
Assessment of the Marine Renewables Industry in Relation to Marine Mammals: Synthesis of Work Undertaken by the ICES Working Group on Marine Mammal Ecology (WGMME) Murphy, S., et al. January 2012 Report Marine Energy general, Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans
Large-Scale Offshore Wind Power in the United States: Assessment of Opportunities and Barriers Musial, M., Ram, B. September 2010 Report Wind Energy general, Offshore Wind Static Device Birds, Fish, Marine Mammals, Socio-economics
Effects of Wind Farms on Harbour Porpoise Behavior and Population Dynamics Nabe-Nielsen, J., et al. September 2011 Report Wind Energy general, Offshore Wind N/A Marine Mammals, Cetaceans
Draft Recovery Plan for the North Pacific Right Whale (Eubalaena japonica) National Marine Fisheries Service January 2013 Report N/A N/A Marine Mammals, Cetaceans
Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing: Underwater Acoustic Thresholds for Onset of Permanent and Temporary Threshold Shifts National Marine Fisheries Service July 2016 Report N/A Noise Marine Mammals
Issuance of Incidental Harassment Authorizations to Deepwater Wind for the Take of Marine Mammals Incidental to Construction of the Block Island Wind Farm and Block Island Transmission System National Marine Fisheries Service August 2014 Report Wind Energy general, Offshore Wind N/A Marine Mammals
Draft Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammals: Acoustic Threshold Levels for Onset of Permanent and Temporary Threshold Shifts National Oceanic and Atmospheric Administration December 2013 Report N/A Noise Marine Mammals
Fish and Marine Mammal Audiograms: A summary of available information Nedwell, J., et al. September 2004 Report N/A Noise Fish, Marine Mammals
Assessment of Sub-Sea Acoustic Noise and Vibration from Offshore Wind Turbines and its Impact on Marine Wildlife; Initial Measurements of Underwater Noise during Construction of Offshore Windfarms, and Comparison with Background Noise Nedwell, J., Langworthy, J., Howell, D. May 2003 Report Wind Energy general, Offshore Wind Noise Fish, Marine Mammals
New York Department of State Offshore Atlantic Ocean Study New York Department of State July 2013 Report Offshore Wind N/A Birds, Fish, Invertebrates, Marine Mammals, Reptiles, Human Dimensions
NYSERDA Environmental Research Program Plan Research Area 4: Marine Wind and Wildlife New York State Energy Research and Development Authority (NYSERDA) September 2015 Report Wind Energy general, Offshore Wind N/A Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Sea Turtles

Pages

Find Tethys on InstagramFind Tethys on FacebookFind Tethys on Twitter
 
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.