Per Halldal

1.1k total citations · 1 hit paper
27 papers, 842 citations indexed

About

Per Halldal is a scholar working on Renewable Energy, Sustainability and the Environment, Oceanography and Ecology, Evolution, Behavior and Systematics. According to data from OpenAlex, Per Halldal has authored 27 papers receiving a total of 842 indexed citations (citations by other indexed papers that have themselves been cited), including 12 papers in Renewable Energy, Sustainability and the Environment, 9 papers in Oceanography and 9 papers in Ecology, Evolution, Behavior and Systematics. Recurrent topics in Per Halldal's work include Algal biology and biofuel production (12 papers), Photosynthetic Processes and Mechanisms (8 papers) and Biocrusts and Microbial Ecology (5 papers). Per Halldal is often cited by papers focused on Algal biology and biofuel production (12 papers), Photosynthetic Processes and Mechanisms (8 papers) and Biocrusts and Microbial Ecology (5 papers). Per Halldal collaborates with scholars based in Norway, Sweden and United States. Per Halldal's co-authors include C. S. French, Gunnar Öquist, Trygve Braarud, Georges Deflandre, Stein Nilsen, Göran Samuelsson and Caj Eriksson and has published in prestigious journals such as Nature, PLANT PHYSIOLOGY and Physiologia Plantarum.

In The Last Decade

Per Halldal

27 papers receiving 757 citations

Hit Papers

Photobiology of microorganisms 1970 2026 1988 2007 1970 50 100 150 200 250
What are hit papers?

Hit papers significantly outperform the citation benchmark for their cohort. A paper qualifies if it has ≥500 total citations, achieves ≥1.5× the top-1% citation threshold for papers in the same subfield and year (this is the minimum needed to enter the top 1%, not the average within it), or reaches the top citation threshold in at least one of its specific research topics.

  1. Photobiology of microorganisms
    1970 288 citations Per Halldal profile →

Peers — A (Enhanced Table)

Peers by citation overlap · career bar shows stage (early→late) cites · hero ref

Name h Career Trend Papers Cites
Per Halldal Norway 13 334 282 260 199 185 27 842
L. R. Blinks United States 10 414 1.2× 242 0.9× 356 1.4× 114 0.6× 162 0.9× 16 1.0k
Larry W. Jones United States 8 214 0.6× 426 1.5× 313 1.2× 268 1.3× 84 0.5× 8 754
Jo‐Ruth Graham United States 13 203 0.6× 435 1.5× 403 1.6× 145 0.7× 76 0.4× 18 727
C. R. Hipkin United Kingdom 18 351 1.1× 242 0.9× 262 1.0× 260 1.3× 182 1.0× 45 963
Janet R. Stein Canada 17 249 0.7× 216 0.8× 223 0.9× 80 0.4× 147 0.8× 35 672
Robert W. Krauss United States 21 345 1.0× 269 1.0× 636 2.4× 200 1.0× 146 0.8× 47 1.4k
Wolfgang Wießner Germany 19 246 0.7× 663 2.4× 416 1.6× 185 0.9× 209 1.1× 61 922
M. Chihara Japan 12 594 1.8× 294 1.0× 199 0.8× 117 0.6× 306 1.7× 29 1.1k
Donat-P. H�der Germany 21 234 0.7× 414 1.5× 180 0.7× 216 1.1× 112 0.6× 31 962
Norma J. Lang United States 19 339 1.0× 451 1.6× 475 1.8× 115 0.6× 201 1.1× 34 1.1k

Countries citing papers authored by Per Halldal

Since Specialization
Citations

This map shows the geographic impact of Per Halldal's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Per Halldal with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Per Halldal more than expected).

Fields of papers citing papers by Per Halldal

Since Specialization
Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Per Halldal. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Per Halldal. The network helps show where Per Halldal may publish in the future.

Co-authorship network of co-authors of Per Halldal

This figure shows the co-authorship network connecting the top 25 collaborators of Per Halldal. A scholar is included among the top collaborators of Per Halldal based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Per Halldal. Per Halldal is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

20 of 20 papers shown
1.
2.
3.
4.
Samuelsson, Göran, Gunnar Öquist, & Per Halldal. (1978). The variable chlorophyll a fluorescence as a measure of photosynthetic capacity in algae. SIL Communications 1953-1996. 21(1). 207–215. 9 indexed citations
5.
Halldal, Per, et al.. (1977). COMPARATIVE ANALYSES OF ACTION SPECTRA OF GLYCOLATE EXCRETION (“PHOTORESPIRATION”) AND PHOTOSYNTHESIS IN THE BLUE‐GREEN ALGA AN ACYSTIS NIDULANS. Photochemistry and Photobiology. 26(5). 511–518. 13 indexed citations
6.
Halldal, Per, et al.. (1975). Quantacorrected Spectrometer for Recording Different Types of Photobiological, Photochemical, and Spectrophotometric Measurements. Physiologia Plantarum. 35(1). 5–10. 11 indexed citations
7.
Halldal, Per, et al.. (1974). Automatic Recordings of Action Spectra for Partial Reactions of Photosynthesis. Physiologia Plantarum. 31(1). 67–72. 8 indexed citations
8.
Halldal, Per. (1970). Photobiology of microorganisms. 288 indexed citations breakdown →
9.
10.
Halldal, Per. (1968). PHOTOSYNTHETIC CAPACITIES AND PHOTOSYNTHETIC ACTION SPECTRA OF ENDOZOIC ALGAE OF THE MASSIVE CORAL FAVIA. Biological Bulletin. 134(3). 411–424. 119 indexed citations
11.
Halldal, Per. (1967). ULTRAVIOLET ACTION SPECTRA IN ALGOLOGY.. Photochemistry and Photobiology. 6(7). 445–460. 39 indexed citations
12.
Halldal, Per. (1966). Light as a controlling factor. NASA Technical Reports Server (NASA). 1 indexed citations
13.
Eriksson, Caj & Per Halldal. (1965). Purification of Phycobilins from Red Algae and Their Fluorescence Excitation Spectra in Visible and Ultraviolet. Physiologia Plantarum. 18(1). 146–152. 3 indexed citations
14.
Halldal, Per. (1964). Ultraviolet Action Spectra of Photosynthesis and Photosynthetic Inhibition in a Green and a Red Alga. Physiologia Plantarum. 17(2). 414–421. 36 indexed citations
15.
Halldal, Per. (1961). Photoinactivations and Their Reversals in Growth and Motility of the Green Alga Platymonas (Volvocales). Physiologia Plantarum. 14(3). 558–576. 8 indexed citations
16.
Halldal, Per. (1960). Action Spectra of Induced Phototactic Response Changes in Platymonas. Physiologia Plantarum. 13(4). 726–735. 9 indexed citations
17.
Halldal, Per & C. S. French. (1958). Algal Growth in Crossed Gradients of Light Intensity and Temperature.. PLANT PHYSIOLOGY. 33(4). 249–252. 56 indexed citations
18.
Halldal, Per. (1958). Pigment Formation and Growth in Blue‐Green Algae in Crossed Gradients of Light Intensity and Temperature. Physiologia Plantarum. 11(2). 401–420. 55 indexed citations
19.
Halldal, Per, et al.. (1954). Observations on Coccoliths of Syracosphaera mediterranea Lohm., S. pulchra Lohm. and S. molischi Schill. in the Electron Microscope. ICES Journal of Marine Science. 19(3). 329–336. 12 indexed citations
20.
Halldal, Per, et al.. (1954). A method for transferring objects from a light microscope to marked areas on electron microscope grids.. PubMed. 9(5-6). 197–200. 3 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

Explore authors with similar magnitude of impact

Breakdown of academic impact, for papers by L. R. Blinks Breakdown of academic impact, for papers by Larry W. Jones Breakdown of academic impact, for papers by Jo‐Ruth Graham Breakdown of academic impact, for papers by C. R. Hipkin Breakdown of academic impact, for papers by Janet R. Stein Breakdown of academic impact, for papers by Robert W. Krauss Breakdown of academic impact, for papers by Wolfgang Wießner Breakdown of academic impact, for papers by M. Chihara Breakdown of academic impact, for papers by Donat-P. H�der Breakdown of academic impact, for papers by Norma J. Lang
Rankless by CCL
2026