Environmental Pollution 257 (2020) 113612
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Foraminifera as bioindicators of water quality: The FoRAM Index revisited* n b, Pamela Hallock c Martina Prazeres a, *, Michael Martínez-Colo a
Marine Biodiversity Group, Naturalis Biodiversity Center, Leiden, Netherlands School of the Environment, Florida A&M University, Tallahassee, FL, USA c College of Marine Science, University of South Florida, St. Petersburg, FL, USA b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 31 July 2019 Received in revised form 10 November 2019 Accepted 10 November 2019 Available online 11 November 2019
Coral reefs worldwide are degrading at alarming rates due to local and global stressors. There are ongoing needs for bioindicator systems that can be used to assess reef health status, the potential for recovery following destructive events such as tropical storms, and for the success of coral transplants. Benthic foraminiferal shells are ubiquitous components of carbonate sediment in reef environments that can be sampled at minimal cost and environmental impact. Here we review the development and application of the FoRAM Index (FI), which provides a bioindicator metric for water quality that supports reef accretion. We outline the strengths and limitations of the FI, and propose how it can be applied more effectively across different geographical regions. © 2019 Elsevier Ltd. All rights reserved.
Keywords: Benthic foraminifera Coral reefs Monitoring Environmental assessment
1. Introduction Across the globe, coral populations and reef accretion have declined as the environmental conditions upon which they depend have been degraded by anthropogenic activities. As a result, reef management agencies are faced with the challenge of managing resources to increase the resilience of local reefs to the broaderscale environmental changes. Because long-term trends in physical and chemical parameters of reef environments can be subtle and masked by diurnal, seasonal and interannual variability, the necessity for bioindicators that integrate environmental conditions was widely recognised by the mid-1990s (e.g. Crosby et al., 1995; Jackson et al., 2000). Evidence for both subtle changes and dramatic losses in coral reef communities emerged in the 1970s. Around the Caribbean, growing human populations were clearing uplands for agriculture and coastlines for urban and tourist development (e.g. Rogers, 1990; Ogden, 1996). With increased fishing pressure on reef fish, the sea urchin (Diadema antillarum) populations exploded, increasing reef bioerosion (e.g. Hay, 1984; Sammarco, 1982), while minimising macroalgal growth; followed by the disease outbreak
* This paper has been recommended for acceptance by Dr. Sarah Harmon. * Corresponding author. E-mail address: martina.prazeres@naturalis.nl (M. Prazeres).
https://doi.org/10.1016/j.envpol.2019.113612 0269-7491/© 2019 Elsevier Ltd. All rights reserved.
and massive dieoff of the urchins in 1983, that has allowed unchecked macroalgal proliferation (Lessios, 2016). On the clearest offshore reefs, white-band disease was destroying stands of Acropora spp. (Antonius, 1977; Bruckner, 2016). In the Pacific, Crown-of-Thorns starfish (Acanthaster planci) outbreaks were being documented (e.g. Sapp, 1999, and references therein). In Kaneohe Bay, Oahu, Hawai’i, in the 1960s and 1970s, coral reefs were being taken over by macroalgae such as Dictyospheria. Concern for the reefs prompted a ground-breaking study of the influence of nutrient pollution on the reef communities (e.g. Laws and Redalje, 1979, 1982; Smith et al., 1981). These studies found, while monitoring sewage discharge into the bay, dissolved inorganic nitrogen was rapidly taken up by phytoplankton, and that chlorophyll a, and particulate nitrogen were much more sensitive and widely applicable indices of nutrient enrichment than inorganic nutrient concentrations. Moreover, because the time frame for influence on benthic biomass and community structure is much longer than for responses within the water column, Laws and Redalje (1982) concluded that the benthos must be considered when assessing the impact of sewage pollution. At about the same time, changes in assemblages of benthic foraminiferal shells in sediments were recognised as indicative of nutrient pollution in tropical coastal waters (e.g. Hirshfield et al., 1968; Seiglie, 1968, 1971). Benthic foraminifera are protists, many of which build calcium carbonate shells, and are a crucial