Study Progress in Riverine Phytoplankton and its Use as Bio-Indicator - a Review

Review Article

Austin J Hydrol. 2014;1(1): 9.

Study Progress in Riverine Phytoplankton and its Use as Bio-Indicator - a Review

Naicheng Wu*, Britta Schmalz and Nicola Fohrer

Department of Hydrology and Water Resources Management, Kiel University, Germany

*Corresponding author: Naicheng Wu, Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, Kiel University, Kiel 24118, Germany

Received: June 01, 2014; Accepted: July 21, 2014; Published: July 26, 2014

Abstract

The value of algae as bio-indicators has already been recognized in the mid of 19th century, however, little attention has been paid to the application of phytoplankton in ecological evaluation of rivers. In this review, we found that studies of phytoplankton showed a long-term increasing trend from 1961 to 2014. However, most of these studies were carried out in oceans, coastal areas, gulfs, lakes and reservoirs, while very few of them (14%) focused on riverine phytoplankton. As well as modeling studies, the utilizations of riverine phytoplankton as bio-indicator are still poorly investigated and the available few studies were those mainly published after the year of 2000. Therefore, we describe 28 algal indices of riverine phytoplankton potentially used for bio-assessment, which belong to community index, growth form, diversity index and biotic index. We also elucidate the calculation and classification methods of 5 common indices proposed in 1950s (Shannon's diversity index, saprobity index) and nowadays (trophic diatom index, Q index and phytoplankton index). Finally, four future directions and applications of riverine phytoplankton research were discussed and proposed: 1) standardization of sampling methods, 2) relations with environmental factors, 3) bio-indication and 4) modeling and predicting dynamics of riverine phytoplankton.

Keywords: Algal metrics; Bio-assessment; Environmental variables; Modeling; Riverine phytoplankton

Introduction

Phytoplankton (mainly planktonic algae), together with benthic algae and macrophytes, constitute the autochthonous primary producers in aquatic ecosystems and form part of the basis of the food web in terms of energy and material input [1]. Due to their short life cycle, planktonic algae respond quickly to environmental changes and are thus a valuable indicator of water quality [2-5] with the aim of effective water resources management and water pollution control. The value of algae as bio-monitor and bio-indicator for human disturbances (e.g. point and diffuse pressures, etc.) has already been recognized in the mid 19th century: the first concept which has been developed was the system of saprobity, which was mainly designed for organic pollution of streams and rivers [6,7]. Moreover, unlike fish and macroinvertebrates, algal communities are usually present before disturbance and generally persist in some form after disturbances. Therefore, application of algal indicators to assess rivers is increasing [8-11]. Recently, diatoms were used as a tracer of water source and hydrological connectivity in the mountainous Attert catchment [12]. The preliminary result of [13] showed that diatoms can help to detect the onset/cessation of surface runoff. Suggested for a meso-scale catchment [14,15] suggested that diatoms could reflect the geographic origin of stream water at the catchment outlet. However, compared to the numerous investigations in lentic water bodies (e.g. oceans, gulfs, lakes and reservoirs) little attention has been paid to the application of the phytoplankton in ecological evaluation of rivers [8].

In this study, by reviewing international scientific literatures, we described the long-term trends of phytoplankton research from past to 2014, with emphasis on riverine phytoplankton. We then summarized the algal indices widely used now for riverine bio-assessment. Based on our reviewed literatures, we finally proposed four possible future directions and applications of riverine phytoplankton research.

Methods and Summary of Literature Reviewed

We searched original papers about phytoplankton by means of Science Direct: https://www.sciencedirect.com/ and Springer link: https://www.springerlink.com/ to inspect the long-term publication trends from 1961 (very few publications before 1960) to 2014 (access on 15th May, 2014). Publications with an article title of "phytoplankton" or "potamoplankton" were searched. The results showed that most of these studies were widely carried out in oceans, coastal areas, gulfs, lakes and reservoirs, and demonstrated an increasing publication trend by the two databases (Figure 1).