New paper on an optimized way of making very small light sensors

Measuring light in the tissue of a coral polyp

This paper descibes a new and optimized way of producing very small (down to 30 µm) scalar irradiance sensors developed by Lars F. Rickelt. These sensors consist of an isotropically light collecting sphere cast on the tip of a single optical fiber. The fiber is mounted in a needle and syringe which allows retraction of the fiber to protect the fiber. This also allows penetration of cohesive tissues as e.g. macroalgae, corals and human epidermis before insertion of the fiber probe. The story was published in the journal Photochemistry and Photobiology and can be accessed [here] or [here].

Poster presentation at PhD day conference at BIO, University of Copenhagen

I presented a poster entitled “Epiphytic microalgae on seagrass leaves impede photosynthesis and radial O2 loss from the roots” at the yearly PhD day at department of Biology, University of Copenhagen. You can access the poster [here].

Epiphyte story featured as ‘Post of the day’ on Frontiers official Facebook and Twitter pages

The newly published story “Epiphyte-cover on seagrass (Zostera marina L.) leaves impedes plant performance and radial O2 loss from the below-ground tissue” was selected as ‘Post of the day’ on the official Facebook and Twitter pages of the publishing group ‘Frontiers’. Please follow the links to the [Facebook] and the [Twitter] posts or access the article [here].

Brodersen KE*, Lichtenberg M*, Paz L-C, Kühl M. 2015. Epiphyte-cover on seagrass (Zostera marina L.) leaves impedes plant performance and radial O2 loss from the below-ground tissue. Frontiers in Marine Science 2

New paper about epiphytism soon to be published in Frontiers in Marine Science

A new manuscript was just accepted by Frontiers in Marine Science, a new interdisciplinary journal. In the study, which was performed during the 2014 ‘Microsensor in the Environmental Sciences’ course, we investigate how epiphytes affect the fitness of seagrass plants. Through detailed measurements of light climate and complete oxygen budgets, we describe how epiphytes significantly reduces the plants ability to perform photosynthesis. Through indirect routes, this affects the plants ability to protect itself from intrusion of plant toxins via the roots which are growing in highly reduced sediment, rich in hydrogen sulphide.

Access the article here

Left) Close-up of seagrass leaf covered in epiphytic algae and microbes. Right) Determining the degree of epiphyte cover of the measured plants.

Manuscript accepted for publication in New Phytologist

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Brown macroalgae are widespread throughout the world and are often dominant and important in temperate coastal zones, but only a few studies have explored the internal physical and chemical microenvironment determining the fitness and performance of the macrophyte. In this project we describe how the tissue of the macroalgae serrated wrack (Fucus serratus) experience a strong light driven stratification of photosynthesis and O₂ consumption over very small scales (less than 1 mm). The data for this study was collected using a range of sensitive electrochemical- and fibre-optic microsensors, including O₂  sensors, scalar irradiance microprobes and microfibers to collect fluorescence signals from photosystem 2 activity.

In the study we show how the functionally distinct tissue layers have different photosynthetic responses by, for the first time, applying internal measurements of photosystem 2 activity, corrected for light gradients.

The study was published in the journal New Phytologist (Impact factor: 7.7) and is available below.

Lichtenberg, M. and Kühl, M. (2015), Pronounced gradients of light, photosynthesis and O₂ consumption in the tissue of the brown alga Fucus serratus. New Phytologist. doi: 10.1111/nph.13396 [Abstract] [Pdf]