A Centuries long History of Participatory Science in Optical Oceanography: from observation to interpretation of natural water colouring (original) (raw)
Related papers
Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide
PLoS ONE, 2013
Marine primary productivity is an important agent in the global cycling of carbon dioxide, a major 'greenhouse gas', and variations in the concentration of the ocean's phytoplankton biomass can therefore explain trends in the global carbon budget. Since the launch of satellite-mounted sensors globe-wide monitoring of chlorophyll, a phytoplankton biomass proxy, became feasible. Just as satellites, the Forel-Ule (FU) scale record (a hardly explored database of ocean colour) has covered all seas and oceans -but already since 1889. We provide evidence that changes of ocean surface chlorophyll can be reconstructed with confidence from this record. The EcoLight radiative transfer numerical model indicates that the FU index is closely related to chlorophyll concentrations in open ocean regions. The most complete FU record is that of the North Atlantic in terms of coverage over space and in time; this dataset has been used to test the validity of colour changes that can be translated to chlorophyll. The FU and FU-derived chlorophyll data were analysed for monotonously increasing or decreasing trends with the non-parametric Mann-Kendall test, a method to establish the presence of a consistent trend. Our analysis has not revealed a globe-wide trend of increase or decrease in chlorophyll concentration during the past century; ocean regions have apparently responded differentially to changes in meteorological, hydrological and biological conditions at the surface, including potential long-term trends related to global warming. Since 1889, chlorophyll concentrations have decreased in the Indian Ocean and in the Pacific; increased in the Atlantic Ocean, the Mediterranean, the Chinese Sea, and in the seas west and north-west of Japan. This suggests that explanations of chlorophyll changes over long periods should focus on hydrographical and biological characteristics typical of single ocean regions, not on those of 'the' ocean. Citation: Wernand MR, van der Woerd HJ, Gieskes WWC (2013) Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide. PLoS ONE 8(6): e63766.
1994
Beginning with the upcoming launch of the Sea, viewing Wide Field-of-view Sensor (SeaWiFS), there should be almost continuous measurements of ocean color for nearly 20 years if all of the presently planned national and international missions are implemented. This data set will present a unique opportunity to understand the coupling of physical and biological processes in the world ocean. The presence of multiple ocean color sensors will allow the eventual development of an ocean color observing system that is both cost effective and scientifically based. This report discusses the issues involved and makes recommendations intended to ensure the maximum scientific return from this unique set of planned ocean color missions. An Executive Summary is included with this document which briefly discusses the primary issues and suggested actions to be considered. 1. INTRODUCTION The development of a 20-year time series of ocean color measurements from satellites starting with the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), presents many scientific opportunities to study long-term variability of biological processes in the upper ocean. These studies will range from the response of the upper ocean ecosystem to global climate change to the management of coastal zone resources. There axe several challenges that must be overcome before these studies can be done. These include: crosscalibration and validation of the different sensors which will be launched by the National Aeronautics and Space Administration (NASA), the National Space Development Agency (NASDA) of Japan, and the European Space Agency (ESA); initiation of a program to ensure comprehensive, coordinated observation and modeling plans; and consistency of data processing and data access. The presence of multiple ocean color sensors will allow the eventual development of an ocean color observing system that is both cost-effective and scientifically based. This report discusses these subjects and makes recommendations to ensure the maximum scientific return from this unique set of planned ocean color missions. The Executive Summary (Section 2), encapsulates the primary points made in this document. The remaining content is an in-depth discussion of these subjects and concerns.
Remote Sensing, 2016
Marine processes are observed with sensors from both the ground and space over large spatio-temporal scales. Citizen-based contributions can fill observational gaps and increase environmental stewardship amongst the public. For this purpose, tools and methods for citizen science need to (1) complement existing datasets; and (2) be affordable, while appealing to different user and developer groups. In this article, tools and methods developed in the 7th Framework Programme of European Union (EU FP 7) funded project Citclops (citizens' observatories for coast and ocean optical monitoring) are reviewed. Tools range from a stand-alone smartphone app to devices with Arduino and 3-D printing, and hence are attractive to a diversity of users; from the general public to more specified maker-and open labware movements. Standardization to common water quality parameters and methods allows long-term storage in regular marine data repositories, such as SeaDataNet and EMODnet, thereby providing open data access. Due to the given intercomparability to existing remote sensing datasets, these tools are ready to complement the marine datapool. In the future, such combined satellite and citizen observations may set measurements by the engaged public in a larger context and hence increase their individual meaning. In a wider sense, a synoptic use can support research, management authorities, and societies at large.
From silk to satellite: half a century of ocean colour anomalies in the Northeast Atlantic
Global Change Biology, 2014
Changes in phytoplankton dynamics influence marine biogeochemical cycles, climate processes, and food webs, with substantial social and economic consequences. Large-scale estimation of phytoplankton biomass was possible via ocean colour measurements from two remote sensing satellitesthe Coastal Zone Colour Scanner (CZCS, 1979(CZCS, -1986 and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, 1998(SeaWiFS, -2010. Due to the large gap between the two satellite eras and differences in sensor characteristics, comparison of the absolute values retrieved from the two instruments remains challenging. Using a unique in situ ocean colour dataset that spans more than half a century, the two satellite-derived chlorophyll-a (Chl-a) eras are linked to assess concurrent changes in phytoplankton variability and bloom timing over the Northeast Atlantic Ocean and North Sea. Results from this unique re-analysis reflect a clear increasing pattern of Chl-a, a merging of the two seasonal phytoplankton blooms producing a longer growing season and higher seasonal biomass, since the mid-1980s. The broader climate plays a key role in Chl-a variability as the ocean colour anomalies parallel the oscillations of the Northern Hemisphere Temperature (NHT) since 1948.
Scientific Reports, 2021
Marine phytoplankton accounts for approximately 50% of all photosynthesis on Earth, underpins the marine food chain and plays a central role in the Earth's biogeochemical cycles and climate. In situ measurements of ocean transparency can be used to estimate phytoplankton biomass. The scale and challenging conditions of the ocean make it a difficult environment for in situ studies, however. Here, we show that citizen scientists (seafarers) using a simple white Secchi Disk can collect ocean transparency data to complement formal scientific efforts using similar equipment. Citizen scientist data can therefore help understand current climate-driven changes in phytoplankton biomass at a global scale. The ocean is a difficult environment to access for in situ study due to its scale, remoteness and challenging conditions. Although ocean science research is vital for our sustainable future 1 , scientific research lags current, climate-driven ocean changes 2. The ocean's phytoplankton account for approximately 50% of all photosynthesis on Earth 3,4 and temporal and spatial changes in the phytoplankton can influence marine productivity 5 , weather 6 and climate 7,8. Monitoring the phytoplankton is therefore essential as an early indicator of regional and global ecosystem change 9-12. Around 44% of the human population lives within 150 km of the coast 13 and a number go to sea for work and recreation. The seafaring public often visits the same locations, whether as sailors on short day trips, commercial fishermen accessing fishing grounds, or offshore yachtsmen/women whose passages follow common routes dictated by the season, prevailing winds and currents 14. Therefore, the seafaring public provides an opportunity to collect oceanographic data over varying spatial and temporal scales to contribute to scientific efforts and many now participate in marine citizen science 15,16. The global Secchi Disk study (http:// www. secch idisk. org) 17 engages seafarers to use a Secchi Disk 18 to collect in situ data on ocean transparency that can be used to estimate phytoplankton biomass 19. The Secchi Disk study uses a simple, 30 cm diameter white Secchi Disk that is weighted and attached to a tape-measure, and lowered vertically into the water from a boat's side. The depth (m) below the surface when the Secchi Disk disappears from sight is the Secchi depth (Z SD), which measures ocean transparency. When the bathymetry is > 25 m depth and the distance > 1 km from shore, the primary influence upon ocean transparency is phytoplankton pigments and their breakdown products and therefore, Z SD estimates phytoplankton biomass in the water column; re-suspended sediments and dissolved organic matter from rivers further reduce transparency and introduce optical errors in shallower water and closer inshore 12. Marine scientists have used Secchi Disks to measure ocean transparency since 1865 20 and archives of Z SD represent one of the longest-running, spatially extensive global marine datasets 21. Recently, the Secchi Disk has fallen from widespread use among marine scientists 22 due to spectrophotometric determination of chlorophyll
Earth System Monitoring, 2012
measured above the water consisting of photons that have penetrated the water column and been backscattered out through the air-sea interface. It does not include photons reflected off the sea surface, also called sun glint. Definition of the Subject, Relevance, Motivation The oceans cover over 70% of the earth's surface and the life inhabiting the oceans play an important role in shaping the earth's climate. Phytoplankton , the microscopic organisms in the surface ocean, are responsible for half of the photosynthesis on the planet. These organisms at the base of the food web take up light and carbon dioxide and fix carbon into biological structures releasing oxygen. Estimating the amount of microscopic phytoplankton and their associated over the vast expanses of the ocean is extremely challenging from ships. However, as primary productivity phytoplankton take up light for photosynthesis, they change the color of the surface ocean from blue to green. Such shifts in ocean color can be measured from sensors placed high above the sea on satellites or aircraft and is called "ocean color remote sensing ." In open ocean waters, the ocean color is predominantly driven by the phytoplankton concentration and ocean color remote sensing has been used to estimate the amount of chlorophyll , the primary light-absorbing a pigment in all phytoplankton. For the last few decades, satellite data have been used to estimate large-scale patterns of chlorophyll and to model primary productivity across the global ocean from daily to interannual timescales. Such global estimates of chlorophyll and primary productivity have been integrated into climate models and illustrate the important feedbacks between ocean life and global climate processes. In coastal and estuarine systems, ocean color is significantly influenced by other light-absorbing and light-scattering components besides phytoplankton. New approaches have been developed to evaluate the ocean color in relationship to colored dissolved organic matter, suspended sediments, and even to characterize the bathymetry and composition of the seafloor in optically shallow waters. Ocean color measurements are increasingly being used for environmental monitoring of , critical coastal habitats harmful algal blooms (e.g., seagrasses, kelps), processes, oil spills, and a variety of hazards in the coastal zone. eutrophication
A History of Oceanography from Space 1.1 A STORY OF TWO COMMUNITIES
The history of oceanography from space is a story of the coming together of two communities—satellite remote sensing and traditional oceanography. For over a century oceanographers have gone to sea in ships, learning how to sample beneath the surface and making detailed observations of the vertical distribution of properties. Gifford Ewing noted that oceanographers had been forced to consider " the class of problems that derive from the vertical distribution of properties at stations widely separated in space and time " (Ewing 1965). With the introduction of satellite remote sensing in the 1970s, traditional oceanogra-phers were provided a new tool to collect synoptic observations of conditions at or near the surface of the global ocean. Since that time, progress has been dramatic. Satellites are revolutionizing oceanography. Yet much remains to be done. Traditional subsurface observations and satellite-derived observations of the sea surface—collected as an integrated set of observations and combined with state-of-the-art models—have proven their ability to yield highly accurate estimates of the three-dimensional, time-varying distribution of properties for the global ocean. Neither satellite nor in situ observing systems can do this on their own. And if such observations can be collected over the long term, they can provide ocean-ographers with an observational capability conceptually similar to that which meteorolo-gists use on a daily basis to forecast atmospheric weather. Our ability to understand and forecast oceanic variability—how the oceans and atmosphere interact—critically depends on an ability to observe the three-dimensional global oceans on a long-term basis.
Shedding Light on the Sea: André Morel's Legacy to Optical Oceanography
Annual Review of Marine Science, 2014
André Morel (1933–2012) was a prominent pioneer of modern optical oceanography, enabling significant advances in this field. Through his forward thinking and research over more than 40 years, he made key contributions that this field needed to grow and to reach its current status. This article first summarizes his career and then successively covers different aspects of optical oceanography where he made significant contributions, from fundamental work on optical properties of water and particles to global oceanographic applications using satellite ocean color observations. At the end, we share our views on André's legacy to our research field and scientific community.