Constantine Alexander's blog

First mission for new ocean floor observatory

GEOMAR installs MoLab on a cold water coral reef in the Norwegian Sea

		The basic configuration of the new modular ocean floor observatory MoLab of GEOMAR (Germany). It consists of one Master Lander, three satellite landers, three eddy correlation modules and two mooring modules. For the maintenance of the modules ROV PHOCA (E) is being used. Graphic: MoLab-AG, GEOMAR

Up to now marine scientists investigating complex processes on the ocean floor have had limited choices. If they wanted to examine large areas on the ocean floor, they could do it only for short periods of time, because research vessels are expensive to use. If they wanted to examine long term processes, they could use autonomous observatories, but they would get measurements from only one point in the ocean. Scientists and technicians of the GEOMAR | Helmholtz Centre for Ocean Research Kiel (Germany) have now developed a modular multidisciplinary seafloor observatory, MoLab, which is able to measure biological, physical, chemical or geological parameters over a period of several months and a range of several square kilometres. On Saturday, 26th May, MoLab set off on board RV POSEIDON on its first scientific mission. "We will install MoLab on a cold water coral reef off the coast of northern Norway. We want to find out why the corals grow at this specific place and what the impact of climate change on the corals will be ", says Dr Olaf Pfannkuche, marine scientist at GEOMAR and chief scientist of the cruise.

MoLab consists of several different devices that can be combined according to the specific scientific question. Among the available modules are single autonomous deep sea observatories (so called "Lander") in different configurations and sizes as well as oceanographic moorings which all have the same basic sensor systems. The core of the MoLab System is a communication module integrated in one of the moorings. "This module communicates with all other modules in the measuring field using acoustic signals. Thus for the first time we will be getting a synchronized and coherent data record from several measurement devices at the ocean floor", explains Dr Pfannkuche. Because no cable connections have to be established in the deep and because the single modules are relatively compact, it is possible to set up or change the MoLab System during an experiment even with medium sized research vessels like RV POSEIDON. To maintain the system in the deep, the scientists will use the brand new ROV PHOCA.

Thus MoLab will enable scientists to investigate the interaction of multiple factors on the ocean floor and in the bottom water layer inexpensively, flexibly and long term. "No process in the ocean stands alone. The topography of the ocean floor influences currents, currents influence the distribution of nutrients and thus biology, organisms build up the ocean floor anew after their deaths. If we want to make progress in research about global change we have to consider all these multiple interactions", underlines Dr Pfannkuche.

The cold water coral reef chosen by the scientists for the first MoLab mission is located in Stjernsund in northern Norway in a water depth of 220 to 350 metres. It's one of the northernmost cold water coral reefs in Europe. For four months MoLab will measure the basic conditions for the growth of the corals and investigate the interactions within the reef's ecosystem. For this MoLab will measure currents, tides, water temperatures, salinity, nutrients, and the consumption of oxygen in and around the reef. Cameras will observe the reef continuously.

The data set thus obtained will later form the basis for numerical simulations. The aim is to better understand oceanographic-biological processes in general. "The new opportunities we have with an observatory like MoLab will improve our knowledge about extremely sensitive ecosystems like arctic cold water corals considerably", says Dr Pfannkuche.

Contact: Jan Steffen
jsteffen@geomar.de
49-431-600-2811
Helmholtz Centre for Ocean Research Kiel (GEOMAR)

 

Nature inspires new submarine design

The water boatman's unique propulsion system was studied by researchers from China

Tourist Submarine by Vorscon

Superhydrophobicity is one of most important interfacial properties between solids and liquids. SHI Yanlong and his group from the College of Chemistry and Chemical Engineering, Key laboratory of Hexi Corridor Resources Utilization of Gansu Universities, Hexi University investigated the superhydrophobicity of the water boatman's hind wings. The study showed that superhydrophobicity plays a crucial role in the water boatman's swimming, balance, and breathing in water, and in its escape ability from water area under unfavorable conditions. Their work, entitled "Investigation of superhydrophobicity on water boatman's hind wings", was published in the Chinese Science Bulletin 2012, Vol 57 (14).

Recently, studies of superhydrophobicity have attracted much interest because of its potential practical applications. In nature, lotus leaves, water-striders' legs, and some insects' wings exhibit perfect superhydrophobicity. Inspired by these superhydrophobic characteristics within living organisms, scientists have invented many ways to fabricate artificial superhydrophobic materials. Superhydrophobic surfaces are commonly constructed either by creating micro/nanostructures on hydrophobic substrates or by chemically modifying micro/nanostructured surfaces with materials of low surface free energy.

Research on superhydrophobicity has seldom focused on insects that live in water. In this report, the authors investigated the water-dwelling water boatman, which belongs to the Corixidae family of the order Hemiptera, suborder Heteroptera. The water boatman can swim freely and breathe in water. The study showed that the superhydrophobicity of the water boatman's hind wings plays a crucial role in its swimming, breathing, and balance, as well as its ability to escape from the water surface under unfavorable conditions.

The water boatman's metapodia are quant-like and keep swinging while it swims; counterforces between the metapodia and water push the water boatman forward or downward. When the metapodia stop swinging, its body begins to float upward because of the buoyancy induced by the perfect superhydrophobicity of the water boatman's hind wings.

Superhydrophobic surfaces are usually induced because of the synergistic effects of hierarchical micro/nanoscale binary structures and low surface free energy. Scanning-electron microscopy studies of the micro/nanoscale structure revealed that the surface of the water boatman's hind wings is composed of mastoids and nanorods with diameters of about 80nm and 50-100nm, with typical mastoid-to-mastoid and rod-to-rod distances of about 50-200nm and 300-1000nm, respectively. Moreover, the insect's wing surface contains low surface energy protein, lipid, and chitin materials, which are hydrophobic. The superhydrophobicity of the water boatman's hind wings is presumed to originate from the combination of such a hierarchical surface structure together with hydrophobic materials contained on the wing. Water contact angles on the wing surface were measured to be 159° and the glide angle was about 8°.

According to Cassie's theory, contact between water droplets and the water boatman's hind wings is a composite contact of solid-liquid-gas. On the rough hierarchical surface, air can be trapped within the micro/nanoscale structures on the wing surface, which makes it difficult for water to enter into the structures to fully wet the surface. The overall contact area between water droplets and air trapped within the micro/nanoscale structures can be roughly estimated to be about 9% (the corresponding contact area between water drops and solid wing surface is about 91%).

The superhydrophobicity of the water boatman's hind wings enables it to swim freely, breathe in water with the assistance of air trapped on its hind wings' surfaces, and escape easily from water area under unfavorable conditions without being affected by moisture.

This research may provide a new strategy for submarine design and the fabrication of a water boatman robot which could swim in water and walk on water surface. Water boatman robots with strong wave resistance and high walking stability on water could be outfitted with miniature biochemical sensors , the biomimetic boatman robots may be used to monitor chemicals at water area for environmental monitoring and cleaning applications, and can be teleoperated or controlled autonomously.

Reference: Wang Y S, Shi Y L, Feng X J, et al. Investigation of superhydrophobicity on water boatman's hind wings (in Chinese). Chin Sci Bull (ChinVer), 2012,57:1227-1230, doi: 10.1360/972011-2636.

Contact: Shi Yanlong
yanlongshi726@126.com
Science in China Press

Raising the profile of soil’s essential contribution to society

Soils play a vital role in the Earth's life-support system, yet their importance and value to society is not always recognised. A recent study suggests that incorporating soils into a National Capital and Ecosystem Services framework will raise the profile of soils and enable soils to be more easily integrated into policy decisions.

Soils are a vital natural resource, but generally are not perceived to be as fundamental to human wellbeing as air and water. Yet soils supply many essential ecosystems services, not only for example, food, feed, fibre and wood, but they also provide a diverse habitat and gene pool from which we obtain medicines, they regulate air quality by storing carbon, they recycle waste and filter water. More-over, they also offer cultural services in the form of archaeological preservation and recreation opportunities, from sports turf to supporting attractive landscapes.

The study, partly funded by the EU’s SoilTrEC project¹, describes soil’s ‘natural capital’ as its stocks of ‘mass, energy and organization’ including all physical, chemical and biological components, for example, mass includes, organic and inorganic material, soil air, soil water, and living organisms in the soil. The flow of soil ecosystem goods and services is supported by soils’ natural capital and depends on the quality of the soil. Human activities may alter the stocks of soils’ natural capital in relatively short timeframes, for example, by clearing forests for intensive agriculture or covering up soils (‘soil sealing’) in urban development.

There is generally a trade-off between the provision of soil ecosystem services and the maintenance of natural capital that supports the provision of goods and services, the study says. However, for sustainable development, it is important that ecosystem services are not obtained at the expense of the natural capital, for example, nutrients used by agriculture must be replaced, erosion avoided, and strip mining should be followed by regeneration to restore soil stocks.

To ensure that soils continue to function for the benefit of society, are adequately protected, and are incorporated into the policymaking processes, this study proposes that a broad framework should be developed to identify and value all elements of soils’ stocks and the ecosystem goods and services that flow from soils to support human wellbeing. The framework should link the concepts of soil natural capital, ecosystem goods and services and soil change that occurs over short timeframes.

The study makes four recommendations to the soil science community to ensure that soils’ important contributions to supporting life are valued within the framework:

1. Develop frameworks to identify the natural capital stocks and ecosystems goods and services provided by soils that support essential natural systems and sustain human life and biodiversity.
2. Establish indicators and ways to monitor changes in the natural capital of soils and soil ecosystem goods and services to provide an evidence-base for land managers and policymakers.
3. Create ways to value soils and to incorporate these values in decision making processes. This includes recognising the value of non-market services, such as flood control and carbon sequestration, in addition to valuing the decline of natural capital and soil stocks.
4. Participate in developing decision- support tools for policymaking.

The researchers urge soil scientists to be actively involved in developing the framework to ensure policy and other decision makers are fully aware of integrating soil in planning decisions.

1. SoilTrEC (Soil Transformation in European Catchments) is supported by the European Commission under the Seventh Framework Programme. 

Source: Robinson, D.A., Hockley, N., Dominati, E. et al. (2011) Natural Capital, Ecosystem Services, and Soil Change: Why Soil Science Must Embrace an Ecosystems Approach. Vadose Zone Journal. 11(1). DOI:10.2136/vzj2011.0051.

Contact: David.Robinson@ceh.ac.uk